Climate averages 1991–2020

Ontario weather
in June.

A hot, very dry month: the 4th warmest and the 3rd driest of the year. Meets the pleasant-weather rule

Long-term climate patterns, not a forecast for a particular trip.

Average high 28.4°C Daytime mean, June
Average low 15.3°C Night-time mean, June
Rainfall 2.4 mm fewer than one day with ≥1 mm
Daylight 14 h Sunrise to sunset, per day
Every month in Ontario · average highYear overview

June is a hot month in Ontario: daytime highs average 28.4°C and nights cool to about 15.3°C. By daytime temperature it is the 4th warmest of the 12 months.

Expect about 2.4 mm of rain on fewer than one day, which makes June a very dry month (the 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 23 min on an average June day.

The nearest other city in this atlas is Chino (7 km away). In June its highs average 27.5°C, 0.9°C cooler than Ontario, with 2.4 mm of rain.

Among the 498 cities listed in the United States, Ontario ranks joint 227th of 498 for the warmest June highs and joint 56th of 498 for the driest June (rainfall, lowest first). The mean June high of those 498 cities is 27.9°C; Ontario is 0.5°C warmer than that mean.

From June to July, average highs rise by 3.4°C to 31.8°C, and monthly rainfall falls from 2.4 mm to 1.7 mm.

The annual picture

June in context

30-year average
Average highAverage low°C
Average daily high and low temperatures by month The same values are available in the monthly table below. Lines show mean daily maxima and minima, not a forecast interval. 05101520253035 JanFebMarAprMayJunJulAugSepOctNovDec

Monthly rainfall

Average total · mm
Average monthly rainfall totalsEach bar is a mean monthly total over 1991–2020. Full numbers are in the table. JanFebMarAprMayJunJulAugSepOctNovDec 1500

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Ontario climate table

1991–2020
Monthly climate averages for Ontario, 1991–2020
MonthAverage highHigh / lowAverage lowRainfall mm/monthRain days ≥1 mm/dayDaylight hours/dayDay­light h/day
January 17.5°C6.4°C6.4°C935.910.210 h
February 17.8°C6.7°C6.7°C1026.610.911 h
March 19.7°C8.2°C8.2°C626.212.012 h
April 22.1°C9.8°C9.8°C253.713.013 h
May 24.6°C12.4°C12.4°C112.213.914 h
June, selected 28.4°C15.3°C15.3°C2.40.314.414 h
July 31.8°C18.6°C18.6°C1.70.514.214 h
August 32.8°C19.3°C19.3°C0.90.213.413 h
September 31.1°C17.7°C17.7°C4.30.912.412 h
October 26.5°C13.8°C13.8°C192.611.411 h
November 21.6°C9.5°C9.5°C252.810.410 h
December 17.2°C6.1°C6.1°C625.39.910 h

Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

June in nearby cities

Distance from Ontario

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Ontario) is explained once on the Ontario year overview and on the Sources, method and limits page.

Pomona, Chino and Chino Hills lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.