Will skies be clear over southern Ontario Monday night? 

Partly clearing skies are likely over most regions, and mostly cloudy skies are more likely over regions near and east of the GTA, where there will be more of the low and mid-level moisture associated with the past weekend’s low pressure trough which is gradually moving eastward from Ontario (illustrated below for early evening). Over regions where skies become clear, the extensive low-level moisture will quickly form fog in many or most regions, and optical surfaces exposed to a clear sky during the evening will quickly become dew-covered.