Will skies be clear over southern Ontario Friday night?
Mostly cloudy skies are expected during the early evening until low-level moisture (illustrated below for early evening) moves south of Ontario and then clearing skies are expected later in the evening and overnight.

Will skies be clear over southern Ontario Thursday night?
Mostly cloudy skies are expected, due to extensive low-level moisture and cloudiness, but some clear periods are likely occasionally over some regions.

Will skies be clear over southern Ontario Tuesday night?

Mostly clear skies are expected over southwestern regions south of Lake Huron, and partly or mostly cloudy skies are likely over most regions southeast of Lake Huron and Georgian Bay, caused by lots of low-level moisture from the lakes that will likely be causing cloudy periods over many regions (illustrated below for Tuesday evening).

Will skies be clear over southern Ontario Friday night?
Mostly clear skies are likely during the evening, followed by increasing cloudiness by or after midnight as upper-level moisture moves eastward over southern Ontario beginning before midnight over southwestern regions (illustrated below for mid-evening).

Will skies be clear over southern Ontario Thursday night?
Mostly clear skies are likely, except for lots of cloudiness over regions south and east of Lake Huron and Georgian Bay caused by lots of low and mid-level moisture (illustrated below for mid-evening) especially before midnight, and then mostly clear skies are likely before morning.

Will skies be clear over southern Ontario Tuesday night?
Partly clear skies are expected, with varying amounts of cloudiness caused by lots of low-level moisture, especially over regions east of Lake Huron and Georgian Bay (illustrated below for mid-evening).

Will skies be clear over southern Ontario Saturday night?
Mostly cloudy skies are expected, except for occasional clearing breaks later in the evening and during early morning as low and mid-level cloudiness gradually moves eastward from southern Ontario overnight.