Will skies be clear over southern Ontario Saturday night?
Cloudy skies are expected during the evening followed by gradually clearing skies after midnight. Lots of low-level moisture will remain over most regions during early morning (illustrated below for early Sunday) and so periods of low clouds are likely to cause occasional cloudy skies and occasional partly clear skies between midnight and morning.

Will skies be clear over southern Ontario Monday night?
Skies are expected to be cloudy during the early evening, becoming partly cloudy about mid-evening, partly or mostly clear after midnight for about 2-3 hours, and then cloudy again before sunrise.
The overnight clearing is expected because mid-level moisture is forecast to move southward from southern Ontario after midnight (illustrated below for the hour after midnight) and then widespread low-level moisture is forecast to move over southern Ontario before dawn and cause low-level clouds over most or all regions.

Will skies be clear over southern Ontario Sunday night?
Mostly cloudy skies are expected to continue over most regions of southern Ontario except for regions approximately near and northwest of the GTA, where skies are partly clear during the afternoon and will most likely remain mostly or partly clear during the evening. Increasing patches of high jetstream-level cloud are likely to appear over these regions until thicker lower-level cloud moves overhead later in the night ahead of Monday's storm system.

Will skies be clear over southern Ontario Thursday night?
Mostly clear skies are expected, except for some low clouds that may persist over some regions during early evening, caused by a region of low-level moisture which is forecast to move eastward from southern Ontario during the evening (illustrated below for early evening) and except for increasing high clouds that may appear over southwestern regions before morning.

Will skies be clear over southern Ontario Tuesday night?
partly or mostly clear skies are expected over many regions, except for some high-level clouds expected during the evening, due to jetstream-level moisture (illustrated below for early evening), and low clouds expected to form east of Lake Huron and near the north lakeshores of Lakes Erie and Ontario, due to low-level moisture (illustrated below for early evening).

Will skies be clear over southern Ontario Monday night?
Partly or mostly clear skies are likely over most regions, except for occasional low clouds overnight and except for some scattered mid-level clouds during the early evening, caused by some regions of low and mid-level moisture forecast to move eastward across southern Ontario (illustrated below for evening).

Will skies be clear over southern Ontario Sunday night?
Mostly clear skies are expected over most regions, except for some scattered low clouds especially over regions south and east of Lake Huron and Georgian Bay.

Will skies be clear over southern Ontario Thursday night?
Partly or mostly clear skies are likely to appear over most regions, except for low-level cloudy periods especially over regions south and east of Lake Huron and Georgian Bay.

Will skies be clear over southern Ontario Wednesday night?
Mostly cloudy skies are likely, due to lots of moisture in the atmosphere, but occasional clear skies may develop over most regions from time to time.

Will skies be clear over southern Ontario Tuesday night?
Partly clear skies are expected, due to lots of low-level moisture (illustrated below for early evening) causing some periods of low-level cloudiness, mixed with periods of mostly clear sky.

Will skies be clear over southern Ontario Monday night?
Partly clear skies are expected over most regions, mixed with occasional periods of mostly cloudy skies due to lots of low-level moisture that is forecast to be over southern Ontario overnight (illustrated below for late evening).

Will skies be clear over southern Ontario Saturday night?
Partly, or mostly clear skies are expected over many regions during the evening, except for more cloudiness south and east of Lake Huron and Georgian Bay. Later, more cloudiness is expected due to increasing mid-level moisture which is forecast to move northeastward over southern Ontario overnight (illustrated below for late evening).

Will skies be clear over southern Ontario Friday night?
Mostly cloudy skies are likely over most regions, especially over the regions south and east of Lake Huron and Georgian Bay, due to lots of moisture in the lower and mid-levels of the atmosphere and cold air flowing across the warm lakes, but clear skies are likely to develop occasionally, especially over southwestern regions.

Will skies be clear over southern Ontario Monday night?

Partly clear skies are likely during the evening, except for lots of low-level cloudiness near and north of GTA due to low-level moisture south and east of Lake Huron and Georgian Bay (illustrated below for early evening) and then skies are likely to become cloudy after midnight (or by late evening in southwestern regions) due to cloudiness ahead of Tuesday’s low pressure trough.

Will skies be clear over southern Ontario Saturday night?
Some clear periods are likely to appear over most regions from time to time, but mostly cloudy skies are more likely to be the situation during most of the night (except for the clear breaks) due to extensive low-level moisture over southern Ontario.

Will skies be clear over southern Ontario Tuesday night?
Partly clear skies are likely to appear over many, or most, regions during the evening except for lots of high-level clouds that may or may not be visible as cirrus clouds, and except for low-level humidity that will likely cause fog in many areas. Increasing mid-level cloudiness is expected to move eastward over southern Ontario later in the evening over southwestern regions and probably after midnight near western Lake Ontario.  

Will skies be clear over southern Ontario Saturday night?
Mostly cloudy skies are expected, except for occasional partly clear skies that may be visible over most regions, but lots of low-level cloudiness, and some jetstream-level clouds, will be over most of southern Ontario during most of the night.

Will skies be clear over southern Ontario Tuesday night?
Skies will most likely become clear over most regions at some time during the evening, except for lake-effect cloudiness over many regions south and east of the Great Lakes during the early evening, and except for some high-level cloudiness that may appear over most regions caused by jetstream-level moisture which is forecast to be over southern Ontario (illustrated below for early evening).

Will skies be clear over southern Ontario Monday night?
Mostly clear skies are expected over southwestern regions west of Lake Huron, and mostly cloudy skies are expected elsewhere, due to lake-effect cloudiness south and east of Lake Huron and Georgian Bay.

Will skies be clear Friday night over southern Ontario?
Skies may appear to be partly or mostly clear during the evening, before widespread cloudiness spreads over southern Ontario by early morning, but lots of high cloudiness will be over most regions (illustrated below for late evening).

Will skies be clear over southern Ontario Thursday night?
Some high cloudiness will most likely be visible over most regions, due to jetstream-level moisture over southern Ontario (illustrated below for early evening) but skies may appear mostly clear in some regions before the moon rises and illuminates the high clouds.

Will skies be clear over southern Ontario Wednesday night?
Clear skies are expected following some low-level clouds over some regions during the early evening, caused by low-level moisture (illustrated below for early evening) which is forecast to move eastward from southern Ontario during the evening.

Will skies be clear over southern Ontario Tuesday evening?
Mostly cloudy skies are expected, although some moonlight may appear during early evening and give the impression of partly clear skies.

Will skies be clear over southern Ontario Monday night?

Lots of jetstream-level moisture (illustrated below for early evening) is expected to cause mostly cloudy skies due to high clouds, although bright super moonlight may give the appearance of clear skies from locations where urban light makes the widespread high cloudiness hard to see.

Will skies be clear over southern Ontario Sunday night?
Clear skies are expected.

Note, no more blog updates will be posted until Nov. 14.

Will skies be clear over southern Ontario Saturday night?
Lots of high, thin cloudiness along the jetstream (illustrated below for late evening) will probably cause skies to be partly cloudy, although bright stars and moonlight may give the impression of clear, starry skies. Also some mid-level clouds may move over some regions, caused by a region of mid-level moisture which is forecast to move over southern Ontario (illustrated below for late evening).

Will skies be clear Friday night over southern Ontario?

Mostly clear skies are expected, except for some scattered low clouds that may appear, caused by low-level moisture flowing southward from Lake Huron and Georgian Bay (illustrated below for early evening) until early morning, when increasing low-level as well as jetstream-level moisture is likely to cause some cloudiness to develop. High, thin jetstream-level clouds may also appear from time to time since the jetstream is and will be over southern Ontario (illustrated below for late evening).

Will skies be clear over southern Ontario Thursday night?
Mostly cloudy skies are likely during the evening over most regions, followed by clearing skies after midnight, due to a region of uplift over southern Ontario during the evening and lots of low-level moisture flowing southeastward over southern Ontario (illustrated below for early evening) that will be available to form low-level clouds over many or most regions.

 Will skies be clear over southern Ontario Monday night?

Skies are expected to be mostly cloudy, except for partly clear skies during the evening before more widespread moisture and cloudiness moves across southern Ontario later in the evening.

The image below shows mid-level moisture forecast over southern Ontario during early evening.

Will skies be clear over southern Ontario Sunday night?
Mostly or partly cloudy skies are expected during the evening, due to low-level moisture causing low clouds over regions south of Lake Huron and Georgian Bay (illustrated below for early evening), followed by clearing skies overnight.

Will skies be clear over southern Ontario Thursday night?
Cloudy skies are expected during the evening, followed by clearing skies overnight as Thursday's low pressure region moves eastward and drier air flows over southern Ontario (illustrated below for low-level moisture during early morning).

Will skies be clear over southern Ontario Tuesday night?

Mostly clear skies are expected except for lake-effect cloudiness over regions south and east of Lake Huron and Georgian Bay, and except for some high clouds that may become visible over southwestern regions before morning, caused by jetstream-level moisture which is forecast to move eastward over the southern Great Lakes region overnight (illustrated below for early morning).

Will skies be clear over southern Ontario Monday night?

Mostly cloudy skies are likely over regions south and east of Lake Huron and Georgian Bay due to extensive  low-level moisture (illustrated below for late evening), and partly or mostly clear skies are likely elsewhere over southern Ontario where lake-effect cloud and winds don’t coincide to cause low-level cloudiness.

Will skies be clear over southern Ontario Saturday night?
Most regions are likely to be under clear skies during the evening, except for regions south and east of Lake Huron and Georgian Bay, where low-level cloudiness is expected (illustrated below for early evening) due to cool air, warm lakes, and the lake-effect cloud process.
More cloudiness is expected to move eastward over southern Ontario and to cause partly cloudy skies during early morning ahead of a low pressure trough.

Will skies be clear over southern Ontario Wednesday night?
Mostly cloudy skies are expected by sunset, except for some locations where there may be enough breaks in the clouds to give the appearance of partly clear skies, and then more widespread cloudiness is expected by late evening as moisture spreads northward ahead of Thursday's low pressure trough.

Will skies be clear over southern Ontario Tuesday night?
Clearing skies are expected during the evening as cloudiness moves eastward from southern Ontario following this afternoon and evening's cold front. Skies will probably be clear by late evening over most regions and then clear overnight, except for occasional patches of low cloud that may appear, caused by diminishing regions of low-level moisture.

Will skies be clear over southern Ontario Monday night?
Gradually clearing skies are expected during the evening as mid-level moisture moves eastward from southern Ontario (illustrated below for early morning, after midnight) following the warm front which is over southern Ontario Monday. Skies are likely to become mostly clear during the early evening in southwestern regions and later in the evening in eastern regions. After the mid-level clouds diminish, high clouds are likely to be present over most regions.

Will skies be clear over southern Ontario Saturday night?
Cloudy skies are expected, except for mostly cloudy skies during the evening with lots of high cloudiness over most regions by sunset, followed by increasing clouds overnight.

Will skies be clear over southern Ontario Friday night?
Mostly clear skies are expected, except for occasional high clouds caused by some regions of jetstream-moisture forecast to move over southern Ontario overnight (illustrated below for early evening).

Will skies be clear over southern Ontario Thursday night?
Mostly clear skies are expected, except for some early-evening low-level clouds that may persist after sunset, and except for low-level cloudiness that may develop during early morning, especially downwind of Lake Huron and Georgian Bay.

Will skies be clear over southern Ontario Wednesday night?
Cloudy skies are expected, except that increasing cloudiness during the evening (due to increasing mid-level moisture, illustrated below for early evening) will probably have enough breaks in the clouds to allow bright moonlight to appear and give the impression of partly clear skies over some locations from time to time.

Will skies be clear over southern Ontario Tuesday night?
Cloudy skies are expected this evening due to lots of high-level moisture moving eastward over southern Ontario (illustrated below for late evening), followed by gradually clearing skies (with gradually less high-level cloud) before morning. The high cloudiness during the evening may occasionally be thin enough to allow bright moonlight to give an impression of clear sky, but generally widespread cloudiness is probably a better description.

Will skies be clear over southern Ontario Monday night?
Mostly clear skies are likely, except for increasing high clouds that may appear in the sky, caused by a large region of jetstream-level moisture which is forecast to move eastward over southern Ontario beginning at about sunset (illustrated below for early evening), and except for increasing cloud cover over southwestern Ontario before morning.

Will skies be clear over southern Ontario Sunday night?
Clear skies are expected. Some low-level clouds may be present at sunset (remaining from the afternoon cloudiness) but would dissipate quickly after sunset.

Will skies be clear over southern Ontario Saturday night?

Clear skies are expected over southwestern regions well south of Lake Huron, and partly cloudy skies are expected elsewhere due to lots of low-level moisture (illustrated below for late evening) that will be available to form low clouds, especially in regions south and east of Lake Huron and Georgian Bay.

Will skies be clear over southern Ontario Friday night?

Skies will most likely be mostly clear during the first couple of hours following sunset, especially in eastern regions of southern Ontario, while southwestern regions are more likely to be under increasing mid-level clouds by sunset, due to mid-level moisture moving northeastward over southern Ontario (illustrated below for early evening) during the evening ahead of Saturday morning’s cold front.

Note: no updates will be possible Wednesday and Thursday.

Will skies be clear over southern Ontario Tuesday night?
Mostly clear skies are likely, except for scattered low clouds that are likely to appear over most regions, remaining from the moisture that has been over southern Ontario during the past several days. Also, fog is likely to form over some regions during the early morning because the dewpoint (and moisture content) of the low-level air is not likely to decrease much today and overnight. Another consequence of the humidity (besides fog patches) will be dew formation on optical surfaces exposed to the clear night sky.

Will skies be clear over southern Ontario Monday night? 

Partly clearing skies are likely over most regions, and mostly cloudy skies are more likely over regions near and east of the GTA, where there will be more of the low and mid-level moisture associated with the past weekend’s low pressure trough which is gradually moving eastward from Ontario (illustrated below for early evening). Over regions where skies become clear, the extensive low-level moisture will quickly form fog in many or most regions, and optical surfaces exposed to a clear sky during the evening will quickly become dew-covered.

Will skies be clear over southern Ontario Tuesday night?
Mostly cloudy skies are likely, except for partly or mostly clear skies over southern parts, near Lakes Ontario and Erie, during the first several hours after sunset, before more substantial mid-level moisture moves over southern Ontario (illustrated below for early evening) and causes partly to mostly cloudy skies over most regions. Over northern regions of southern Ontario (closer to Lake Huron and Georgian Bay), skies are more likely to be mostly cloudy.

Will skies be clear over southern Ontario Monday night?
Clear skies are expected, except for cloudiness during early evening over regions near GTA until moisture and cloudiness moves eastward from southern Ontario by mid-evening. Some high clouds may also be visible due to the jetstream moving eastward across southern Ontario overnight.

Will skies be clear over southern Ontario Wednesday night?
Lots of mid and high-level moisture (illustrated below for early evening) will be present to cause some visible cloud, especially during the evening, and then less cloud after approximately midnight may cause the sky to appear mostly clear.

Will skies be clear over southern Ontario Tuesday night?
Clear or mostly clear skies are expected during most of the night, except for some high clouds that may appear over some regions, caused by a region of mid-level moisture forecast to move over southern Ontario overnight (illustrated below for late evening), and then some high clouds are likely to appear before sunrise.

Will skies be clear over southern Ontario Monday night?
Skies are expected to be mostly clear during the evening (except for high cloud that may be visible) and then partly cloudy skies are expected by about midnight as mid-level moisture moves over southern Ontario (illustrated below for late evening) ahead of a weak cold front.

Will skies be clear over southern Ontario Saturday night?
Clearing skies are expected as mid-level moisture moves eastward from southern Ontario during the evening (illustrated below for late evening) and then low-level clouds, including fog, are likely to form after midnight over some regions.

Will skies be clear over southern Ontario Friday night?
Cloudy skies are expected, except for partly clear skies during the evening over most regions before widespread cloud moves over southern Ontario by or shortly after midnight. Lots of high clouds will likely be visible during the evening, due to lots of jetstream-level moisture which is forecast to move over southern Ontario by evening (illustrated below for early evening).

Will skies be clear over southern Ontario Thursday night?
Skies are likely to be clear or mostly clear, except for some high clouds that may appear in the bright moonlight occasionally over some regions, caused by regions of jetstream-level moisture which are forecast to move over southern Ontario overnight (illustrated below for late evening).

Will skies be clear over southern Ontario Wednesday night?
Clear skies are expected, as a large high pressure ridge spreads over Ontario during Wednesday and overnight.

Will skies be clear Tuesday night over southern Ontario?
Cloudy skies are expected due to lots of mid and high-level moisture moving over southern Ontario, except that skies may appear partly cloudy during the evening in locations where breaks in the high cloudiness allow the moon and brighter stars to be visible and give the impression of partly clear skies.

Will skies be clear over southern Ontario Monday night?

Mostly clear skies are expected, except for some high cirrus cloud that may be visible in the bright moonlight during the evening due to jetstream-level moisture which is forecast to move over southern Ontario overnight (illustrated below for late evening).

Will skies be clear over southern Ontario Sunday night?
Clear skies are expected, after some possible periods of low-level cloudiness that may persist for several hours after sunset over some regions.

Will skies be clear over southern Ontario Saturday night?
After midnight, clearing skies are likely as moisture moves eastward from southern Ontario (illustrated below for early Sunday morning). Some regions southeast of Lake Huron and Georgian Bay may remain cloudy, and some high cirrus cloud may be visible due to the jetstream moving over southern Ontario after midnight.

Will skies be clear over southern Ontario Thursday night?

Clearing skies are expected during the evening as mid and high-level moisture moves eastward during the evening (illustrated below for late evening). Skies may be mostly cloudy at sunset (especially in regions close to Lakes Erie and Ontario) and then clear by midnight.

Will skies be clear Wednesday night over southern Ontario?
Mostly cloudy skies are likely, except that lots of breaks in the low and mid-level moisture may allow skies to occasionally be clear enough over some or most regions for the moon and bright stars to be visible, even through the high cloud and low-level humidity.

Will skies be clear over southern Ontario Tuesday night?

Lots of moisture will be available to cause clouds at all levels, and high humidity will cause skies to appear hazy, but mid-evening skies will probably appear starry (except for widespread high-level clouds) due to a region of less mid-level moisture  which is forecast to move over most regions of southern Ontario overnight (illustrated below for late evening).

More clear skies Monday night!
(Except for some thin cirrus overnight, followed by increasing high cloudiness before morning.)

Continuing clear skies (other than very thin cirrus) - no need for an update!

Will skies be clear over southern Ontario Friday night?

Clear skies are expected.

Will skies be clear over southern Ontario Thursday night?
Mostly clear skies are expected, except for some low-level clouds during early evening that are likely to diminish overnight as low-level moisture (illustrated below for early evening) moves southward from southern Ontario during the evening.

Will skies be clear over southern Ontario Wednesday night?

Clear skies are expected over most regions, except for some low-level clouds near western Lake Ontario during the evening until a region of low-level moisture moves southward from southern Ontario overnight (illustrated below for late evening). Some thin jetstream-level clouds might also be visible from time to time (due to the jetstream extending west-to-east across southern Ontario), and some low-level clouds are likely to develop south of Lake Huron before morning.

Will skies be clear over southern Ontario Tuesday night?
Cloudy skies are expected, except that partly cloudy skies are possible during the evening over some regions where breaks in the increasing mid-level cloudiness allow the brighter stars and planets to appear and give the impression of partly clear skies, particularly in urban areas where the increasing high-level thin clouds may not be apparent.

Will skies be clear over southern Ontario Monday night?

Mostly clear skies are expected, with several exceptions:

-some low-level clouds may be over the GTA and western end of Lake Ontario during early evening due to a region of low-level moisture (illustrated below for mid-evening)

-some jetstream-level cloud may be visible over southwestern Ontario during the evening due to the jetstream winds moving eastward over southern Ontario overnight (jetstream-level moisture illustrated below for early evening)

-some mid-level clouds may develop over some regions after midnight due to mid-level moisture which is forecast to move eastward over southern Ontario before morning, ahead of Tuesday’s low pressure trough over the Great Lakes region