Climate averages 1991–2020

Mississauga weather
in September.

A mild, moderately wet month: the 4th warmest and the 7th driest of the year.

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

Average high 21.3°C Daytime mean, September
Average low 13.5°C Night-time mean, September
Rainfall 75 mm 9 days with ≥1 mm
Daylight 13 h Sunrise to sunset, per day
Every month in Mississauga · average highYear overview

September is a mild month in Mississauga: daytime highs average 21.3°C and nights cool to about 13.5°C. By daytime temperature it is the 4th warmest of the 12 months.

Expect about 75 mm of rain on roughly 9 days, which makes September a moderately wet month (the 7th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 33 min on an average September day.

The nearest other city in this atlas is Etobicoke (10 km away). In September its highs average 21.2°C, about as warm as Mississauga, with 69 mm of rain.

Among the 86 cities listed in Canada, Mississauga ranks joint 11th of 86 for the warmest September highs and joint 26th of 86 for the driest September (rainfall, lowest first). The mean September high of those 86 cities is 19.8°C; Mississauga is 1.5°C warmer than that mean.

From September to October, average highs fall by 7.1°C to 14.2°C, and monthly rainfall rises from 75 mm to 83 mm.

The annual picture

September 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. -15-10-5051015202530 JanFebMarAprMayJunJulAugSepOctNovDec

Monthly precipitation

Average total · mm
Average monthly precipitation totalsEach bar is a mean monthly total over 1991–2020. Full numbers are in the table. JanFebMarAprMayJunJulAugSepOctNovDec 1000

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

Every month, side by side

Mississauga climate table

1991–2020
Monthly climate averages for Mississauga, 1991–2020
MonthAverage highHigh / lowAverage lowPrecipitation mm/monthWet days ≥1 mm/dayDaylight hours/dayDay­light h/day
January -1.2°C-8.4°C-8.4°C7010.99.39 h
February -0.6°C-9.0°C-9.0°C568.710.510 h
March 4.3°C-4.5°C-4.5°C659.611.912 h
April 10.9°C1.7°C1.7°C8911.313.413 h
May 17.7°C8.1°C8.1°C8110.914.715 h
June 23.1°C14.2°C14.2°C8211.315.415 h
July 26.0°C17.4°C17.4°C7410.115.115 h
August 25.1°C17.0°C17.0°C669.414.014 h
September, selected 21.3°C13.5°C13.5°C759.112.613 h
October 14.2°C7.3°C7.3°C8311.111.111 h
November 7.3°C1.2°C1.2°C7710.29.710 h
December 1.8°C-4.0°C-4.0°C7010.69.09 h

Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet 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

September in nearby cities

Distance from Mississauga

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 Mississauga) is explained once on the Mississauga year overview and on the Sources, method and limits page.

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