Will skies be clear over southern Ontario Wednesday night?
Partly clear skies are expected over most regions, due to lots of mid-level clouds caused by mid-level moisture which is forecast to move over southern Ontario by about mid-evening (illustrated below for Wednesday night in the 500 hPa level moisture chart). The clearest skies may occur during early evening, after moisture at the 700 hPa level moves eastward from southern Ontario (illustrated below for early evening) and before the moisture at the 500 hPa level moves over southern Ontario.

Will skies be clear over southern Ontario Tuesday night?
Mostly clear skies are likely over southwestern regions during the evening, followed by increasing high cloudiness before morning, while mostly cloudy skies are likely over regions generally between Lake Ontario and Lake Huron, due to lots of mid-level moisture which is forecast to be over these regions during the evening (illustrated below for mid-evening), followed by increasing high cloudiness.

Will skies be clear over southern Ontario Monday night?
Clear skies are expected, except for some low clouds that may appear after midnight over some regions, due to some low-level moisture which is forecast to move over southern Ontario (illustrated below for early morning) and except for some thin high clouds that may appear occasionally overnight.

Will skies be clear over southern Ontario Sunday night?
Mostly clear skies are likely, except for some low clouds especially during early evening over some regions, due to some low-level moisture which is forecast to diminish and move eastward from southern Ontario during the night (illustrated below for early evening). Later, near or after midnight, some jetstream-level cloudiness is likely to move over some regions.

Will skies be clear over southern Ontario Thursday night?

Mostly cloudy skies are expected, except that skies may become partly clear over some regions during the evening for several hours with lots of scattered cloud before becoming completely cloudy.

Will skies be clear over southern Ontario Wednesday night?

Cloudy skies are likely, except for partly clear skies for several hours following sunset near the GTHA and western Lake Ontario, due to mid-level moisture moving eastward from southern Ontario during the afternoon (illustrated below [700 hPa moisture chart] for early evening) and before high-level moisture over southwestern Ontario moves eastward over the western Lake Ontario area later in the evening (illustrated below [250 hPa moisture chart] for mid-evening).

Note: no more updates until Monday February 19.
Clear skies!

Will skies be clear over southern Ontario Thursday night?
Mostly clear skies are likely over some regions during the evening, but the regions between southern Lake Huron and Lake Ontario are likely to be under partly or mostly cloudy skies, due to extensive cloudiness caused by a region of low-level moisture (illustrated below for early evening). Then after or by about midnight, increasing high-level cloudiness is expected ahead of Friday's low pressure trough.

Will skies be clear over southern Ontario Wednesday night?

Clearing skies are expected during early evening as mid-level moisture moves eastward from southern Ontario (illustrated below for mid-evening) and then some low-level clouds are likely to appear occasionally over some regions, especially over regions south and east of Lake Huron and Georgian Bay.

Will skies be clear over southern Ontario Sunday night?

Clearing skies are expected over southwestern regions during the evening and after midnight near the GTHA, after mid-level moisture moves eastward (illustrated below for early Monday).

Will skies be clear over southern Ontario Friday night?
Skies may appear mostly clear during early evening, except for some low-level clouds south and east of Lake Huron and Georgian Bay, but some mid-level cloudiness is likely to be over most regions due to increasing amounts of mid-level moisture (illustrated below for early evening). The mid-level cloudiness may not be visible during early evening, especially before moonrise (a few hours after sunset) but is likely to gradually increase during the night as the mid-level moisture increases in the atmosphere, and then cloudy skies are likely before morning.