Game News: The Sims 4 Seasons: Everything You Need To Know About Weather
Temperatures range from freezing to a heatwave and, your Sims will also encounter sun, rain, snow, and clouds in different combinations.
If you want to know what the weather will be, for instance, if you are planning an outdoor wedding, and want some sunshine, the calendar is your friend
The weather in Willow Creek is quite variable but follows, a fairly traditional Northern Hemisphere pattern
Source