Will skies be clear over southern Ontario Thursday night?
It looks like skies will become mostly or completely clear over most regions after sunset with dry air aloft and subsidence aloft ahead of a ridge building over the Great Lakes region. Afternoon cloudiness over some regions will be dissipating by or shortly after sunset.

Will skies be clear Wednesday night over southern Ontario?
It looks like skies will become mostly clear during the evening. Afternoon cloudiness will begin to dissipate by sunset and skies ought to be mostly clear by an hour or so after sunset. Some mid-level cloudiness might be seen over some regions, caused by an area of mid-level moisture (pictured below) that is forecast to be over southern Ontario during the evening.

Will skies be clear Tuesday night over southern Ontario?

It looks like partly or mostly clear skies are likely during the evening, with some mid-level moisture available to cause some mid-level cloudiness over some regions, especially closer to Lake Huron.

Will skies be clear over southern Ontario Sunday night?
It looks like clear skies are expected, except for some low-level cloudiness over some regions that may persist into the evening from Sunday afternoon low cloud formation.

Will skies be clear over southern Ontario Friday night?

It looks like clear skies during Friday will persist into night, but some high jetstream-level cirrus will be over southern Ontario and will probably appear as visible high cloud in the bright moonlight, especially east of Toronto during the evening.

Will skies be clear over southern Ontario Thursday night?

High pressure ridge, clear skies!

(Bonus, dry air and winds from northeast-expect minimum dew formation.)

Will skies be clear Thursday night over southern Ontario?
Mostly clear skies are expected! (Some low cloud will be persisting after sunset but diminish during the evening.)