Lots of mid-and high-level cloudiness moving eastward over the Great Lakes region during Wednesday will be causing partly or mostly cloudy skies overnight, although some regions may occasionally have less cloud and may appear from urban areas to be partly or mostly clear, with the brighter stars and planets visible.

Will skies be clear over southern Ontario Tuesday night?

Skies ought to be clear, except for increasing jetstream-level moisture overnight (illustrated below) that will be moving eastward across southern Ontario overnight, and that may or may not appear as cirrus clouds.

Will skies be clear over southern Ontario Thursday night?
Mostly cloudy skies are expected with increasing high cloudiness overnight, but some breaks in high-level moisture (illustrated below) might allow brighter stars to be visible and give the impression of partly clear skies from time to time during the evening.

Will skies be clear over southern Ontario Wednesday night?

It looks like most of the mid-level moisture will be east of southern Ontario (illustrated below) by the end of twilight, and skies will be clearing following the passage of this afternoon’s cold front. Some high-level moisture may persist and might be visible as high cloudiness over some regions.

Will skies be clear over southern Ontario Tuesday night?

Skies will most likely be clear by twilight, as a weak high pressure ridge moves eastward across southern Ontario overnight, and skies are clearing as expected during Tuesday afternoon with some afternoon convection cloudiness likely to diminish around sunset and jetstream-level cloudiness moving eastward following the cold front.

Some haze may appear in the sky (or may remain invisible) resulting from a thick plume of smoke aloft from forest fires in Saskatchewan that is moving eastward across the central Great Lakes region during Tuesday afternoon and is expected to move eastward overnight toward southern Ontario.

Will skies be clear over southern Ontario Saturday night?

Mostly clear skies are likely except for jetstream-level moisture (illustrated below for late evening) that may appear as high, thin cloudiness from time to time over most locations, and that may become thicker and more widespread by early Sunday morning.

Will skies be clear over southern Ontario Friday night?

It looks like skies will become clear during late evening as moisture (illustrated below) along a low pressure trough moves southeastward from southern Ontario during the evening. So, skies may become clear near or after midnight.