Mild
Average highs are around 25°C, so days are mild rather than hot.
September verdict
Ottawa, Illinois, United States in September
Weather score62Good
Good for holiday weather
Average highs are around 25°C, so days are mild rather than hot. Sunshine averages 7.5h per day, enough for a balanced month. Rainfall averages 92mm, so some wet days are possible.
September weather
Monthly averages
Temp
25°C
Rain
92mm
Sun
7.5h
Weather score
62
Good
Seasonal climate calendar
TemperatureTemp
RainRain
SunSun
Weather scoreWeather score
Trip feel
Showers
Rainfall averages 92mm, so some wet days are possible.
Some sun
Sunshine averages 7.5h per day, enough for a balanced month.
Map
Weather map
Compare Ottawa, Illinois, United States with nearby places by weather score, rain, sun, temperature, and swim conditions.
Temperature
September25°C average high
September sits in the warmer part of the year, so midday sightseeing can feel heavier than in cooler months.
Warmest monthsMay to September
This stretch sets the upper range for average daytime heat.
Rain
September92mm average rain
September is one of Ottawa's wettest months, so rain is likely to be a major planning factor.
Driest monthsJanuary to February, October, and December
This is the drier part of the year, when outdoor plans usually need less weather flexibility.
Sun
September7.5 hours average sun
September sits close to Ottawa's yearly sunshine average, so it is a middle-of-the-pack month for bright days.
Brightest monthsMay to August
This stretch has the strongest sunshine in the monthly averages.
Weather score
September62 weather score
September sits close to Ottawa's yearly weather-score average, giving a typical overall read on the month.
Best weather monthsJune to August
These months have the strongest weather score in the monthly averages.
