Will skies be clear over southern Ontario Monday night?

Skies will most likely become partly or mostly clear during the evening over most regions as cloudiness with this afternoon's cold front moves eastward from southern Ontario, except for southwestern regions (where cloudiness may remain), and some cloudiness south and east of Lake Huron and Georgian Bay due to low-level moisture (illustrated below for Monday evening). After midnight, increasing moisture ahead of Tuesday's low pressure trough (illustrated below for early Tuesday) will cause increasing cloudiness over all regions.

Will skies be clear over southern Ontario Friday night?

Partly or mostly clear skies are likely, except for occasional mid and high-level cloudiness over most regions caused by some areas of moisture that are forecast to move across southern Ontario (illustrated below), and some low-level clouds that may be more prevalent near lakeshores.

Will skies be clear Thursday night over southern Ontario?

Clearing skies are likely around or after sunset as cloudiness moves eastward from southern Ontario and a high pressure ridge gradually begins to spread eastward over the Great Lakes region. Some low-level moisture is likely to cause some low-level cloudiness over some regions, primarily south and east of Lake Huron and Georgian Bay.

Will skies be clear over southern Ontario Tuesday night?
Skies are likely to remain partly clear during the early evening, until moisture spreads northward (illustrated below) and causes increasing cloudiness over most regions by late evening. Southern regions, just north of Lakes Ontario and Erie, will probably become mostly cloudy by (or soon after) sunset and northern regions of southern Ontario may remain mostly clear until about mid-evening.

Will skies be clear over southern Ontario Monday night?

Mostly clear skies are likely, except for some high clouds that are more likely after midnight over northern regions of southern Ontario, caused by a region of mid-level moisture (illustrated below) associated with a weak upper-level weather disturbance that is forecast to move eastward across the Great Lakes region overnight.

Will skies be clear over southern Ontario Sunday night?
Skies will most likely become mostly clear before sunset, after the cloudiness that's over southern Ontario Sunday afternoon moves eastward and a high pressure ridge spreads eastward over Ontario during Sunday and Sunday night.
Then, skies are likely to become partly or mostly cloudy during mid-evening as mid-level moisture (illustrated below) and lift ahead of an upper-level trough spread southward over southern Ontario during the evening.
So, in summary, skies will most likely be mostly clear during the early evening and then become mostly cloudy.

Saturday: no updates will be posted for Saturday night.
Have a great weekend!

Will skies be clear over southern Ontario Friday night?
Cloudy skies are likely overnight, until skies become mostlyclear several hours before sunrise.
During the early morning, mid-level moisture is forecast to move eastward from southern Ontario (illustrated below for 4 am EST) and allow clearing skies to develop, except for some scattered low-level clouds that will likely form from low-level moisture that may be present.

Will skies be clear over southern Ontario Thursday night?
Skies will be mostly clear during the evening over eastern regions, near the GTHA, except for high jetstream-level cirrus that may be visible by sunset. Further west, in southwestern regions, the cirrus will most likely be covering the sky by sunset. The jetstream-level moisture (illustrated below) is forecast to increase during the evening, but mid-level moisture is forecast to move eastward during the evening and to cause mid-level cloudiness over southwestern regions early in the evening and over eastern regions of southern Ontario by late evening.

Will skies be clear over southern Ontario Wednesday night?

Clear skies are expected over all regions as a strong high pressure ridge builds eastward over southern Ontario later Wednesday and overnight. Some low-level moisture may cause some scattered low clouds to be visible during the evening until the moisture has moved east of southern Ontario by late evening.

Will skies be clear over southern Ontario Sunday night?

It looks like skies will be mostly clear during the evening, except for some low-level clouds over southern Ontario during the afternoon that might persist during and after sunset before dissipating, and except for some high cloudiness that will cause mostly cloudy skies in southwestern regions by sunset and will be gradually increasing overnight over the rest of southern Ontario.
Over regions east of southwestern Ontario, the high cloudiness may cause visible high clouds at some times and other times not be visible, until increasing mid to high-level moisture spreads eastward over southern Ontario (illustrated below for the hour after midnight) and causes mostly cloudy skies by morning over most regions.

Will skies be clear over southern Ontario Saturday night?

Clear skies are expected over most regions, resulting from dry air and subsidence ahead of a strong high pressure ridge, except for partly cloudy conditions south and southeast of Lake Huron and Georgian Bay, where lake-effect cloudiness is likely to form.

Will skies be clear over southern Ontario Friday night?

Skies are likely to start clearing before midnight, as moisture moves southward (illustrated below) following passage of a strong cold front. Skies will most likely be mostly clear after midnight, except for lake-effect cloud over many regions south of Georgian Bay and Lake Huron (illustrated below).

Will skies be clear over southern Ontario Saturday night?
Partly clear skies is the best description for skies that will most likely have some cloudiness at low and mid levels. The illustration below shows some moisture forecast at mid levels during the evening, but it should be considered as an example of the situation at most levels, any time of the night, since some moisture will be present to cause some clouds in the sky over any particular region.
So, in summary, partly clear skies are likely with some cloudiness.

Will skies be clear over southern Ontario Thursday night?

Mostly cloudy skies seem likely, except for less cloudiness in regions near and north of GTA, and eastward over eastern Ontario. A region of moisture at lower and mid-levels (illustrated below) is forecast to move eastward over southern Ontario Thursday night ahead of a weak mid-level trough and this moisture is likely to appear as cloudiness. Regions near and east of GTA will likely have less cloudiness during the evening, until the moisture and cloudiness moves eastward over eastern parts of southern Ontario later in the evening.
In summary: partly clear skies near and east of GTA during early evening, mostly cloudy elsewhere over most of southern Ontario.

Will skies be clear over southern Ontario Wednesday night?

It looks like skies will most likely be clear over southern parts of southern Ontario during the first several hours after sunset, and then become mostly cloudy by about mid-evening. Elsewhere, skies are likely to be cloudy by evening. 

Clear skies following Wednesday afternoon’s cold front will be followed by increasing low and mid-level moisture which is forecast to move eastward across southern Ontario during early evening (illustrated below at EST 19:00) and the moisture is likely to cause skies to become mostly cloudy over most or all regions by about mid-evening.

Will skies be clear over southern Ontario Monday night?

Some clear skies are likely over some regions during the early evening, due to the dry air causing the partly clear skies Monday afternoon, until more extensive cloudiness spreads over most regions by late evening. Some mid and high-level clouds will most likely be visible during the early evening, due to moisture at mid and upper levels over many regions (illustrated below for the 500 and 700 hPa levels) as well as some patches of uplift (not illustrated) contributing to form clouds from the moisture. Low-level moisture is likely to be more widespread later in the evening (illustrated below for late evening at the 925 hPa level) and this is the main factor that is likely to cause more widespread low-level clouds later in the evening over most regions of southern Ontario.