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.