Will skies be clear over southern Ontario Sunday night?
Mostly cloudy skies are expected over most regions, due to widespread high cloud that is over southern Ontario during Sunday afternoon, but some regions near the northern edge of the cloud shield may occasionally have thin high cloud that will allow the brighter stars and planets to be visible and cause the appearance of partly or mostly clear skies.

Will skies be clear over southern Ontario Friday night?
Partly or mostly clear skies are likely, except for lots of high cloud due to high-level moisture which is forecast to be over southern Ontario (illustrated below for late evening).

Will skies be clear over southern Ontario Thursday night?
Clear skies are expected, except for some high cloud that may appear after midnight over most regions, due to jetstream-level moisture which is forecast to move over southern Ontario early Friday (illustrated below for early Friday).

Will skies be clear over southern Ontario Tuesday night?
Partly clear skies are expected due to lots of low-level clouds over most regions caused by moisture which is forecast to be over southern Ontario (illustrated below for late evening) during most of the night.

Will skies be clear over southern Ontario Monday night?
Mostly cloudy skies are expected over most regions, due to lots of mid-level moisture during the evening (illustrated below for late evening) until a weak cold front moves southward across southern Ontario and then less cloudiness is likely by early morning.

Will skies be clear over southern Ontario Saturday night?
Mostly clear skies are expected, except for some scattered low clouds that may appear due to some low-level moisture which is forecast to be over southern Ontario (illustrated below for late evening).

Will skies be clear over southern Ontario Friday night?
Partly cloudy skies are expected due to lots of low cloudiness caused by low-level moisture (illustrated below for early Saturday) but breaks in the cloud may cause skies to occasionally become partly or mostly clear over most regions.