The best time to visit Ontario
Month-by-month climate averages for Ontario, CA, so you can pick your dates on data rather than guesswork.
The most comfortable time to visit Ontario is usually January, March, April and May, when daytime highs sit in the pleasant 60-78°F range and the heaviest February rain is behind you.
Ontario is warmest in August (highs near 93°F) and coldest in December (lows around 42°F), with roughly 22 inches of precipitation across the year and February the wettest month. The sweet spot for most visitors is January, March, April and May.
These are long-run averages. For the actual days you are travelling, check the live Ontario forecast - and note how much the models agree, because that tells you how much to trust it.
Ontario weather by month
what to expect in Ontario through the year, 1991-2020 averagesHere is Ontario's typical weather in each month: the average daytime high and overnight low in °F, how each month feels, and the wettest month marked. Use it to plan any trip to Ontario by season.