CanadaAverage weather for Thunder Bay in September
It's pleasantly warm in September in Thunder Bay with an average temperature of 19°C. Temperatures this month range from a low of 14°C to a high of 23°C. At night, you can expect temperatures between 5°C and 11°C.
Start of September
The month of September starts in Thunder Bay with mild temps, averaging around 21°C during the day and nights around 10°C. A few showers might pop up early in the month, but overall, it’ll stay mostly sunny and dry.
Mid September
By mid-September, daytime temps drop to around 20°C, with nights around 10°C. There’s a chance of some showers during this time, but plenty of dry and sunny days too.
End of September
By the end of September, the average daytime temperature in Thunder Bay is around 18°C, while nighttime temps are about 8°C. A shower might pop up, but overall, the weather will be dry and sunny.
In September, there is an average of 81 mm of precipitation, spread over 10 days. The wind speed is around 4 Bft, mostly coming from the South.
Thunder Bay in September |
New York | ||
|---|---|---|---|
 Average temperature |
19°C | 27°C | |
 Max. temperature |
23°C | 31°C | |
| Min. temperature |
14°C | -5°C | |
 Total precipitation |
81 mm | 57 mm | |
| Rainy days |
10 days | 9 days | |
August
UV index
The UV index is a maximum of 5 this month. That's a moderate value on the intensity scale of 1 to 11. Unprotected skin can burn in about 30 minutes.
Is September a good time to visit Thunder Bay?
Looking for great weather? September is a good time to be in Thunder Bay. The temperatures are nice, and there’s not too much rain.
Temperature records
With 32°C in 2023, Thunder Bay reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 6°C in 2018. The extreme nighttime temperatures ranged from a lowest recorded value of -3°C to a highest value of 19°C.
Check out the climate of Thunder Bay for all months and discover the best travel time
Curious about the weather in other parts of Canada? Check out the climate and weather for spots like Vancouver, Toronto, Niagara Falls, or explore other destinations in Canada.
Daily Temperature in September in Thunder Bay
This chart shows the average daily high and low temperatures in September for Thunder Bay, in degrees Celsius. The red line represents the highs, and the blue line shows the lows. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, provide the average temperatures for this month.
Daily Precipitation in September in Thunder Bay
The chart below shows the average daily precipitation in September for Thunder Bay, measured in millimeters over the past few years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are listed at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that it rained more often. But remember, it’s just an average, and every day can be different. Based on historical weather data for September, you can expect about 10 days of precipitation in Thunder Bay.
Daily UV index in September in Thunder Bay
This chart shows the average daily UV index in September in Thunder Bay, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in September in Thunder Bay over the years
This chart shows the average temperature in September in Thunder Bay, measured in degrees Celsius, over the past few years.
Total precipitation in September in Thunder Bay over the years
This chart shows the average precipitation in September in Thunder Bay, measured in millimeters over the past years. Precipitation is always measured as water, whether it’s snow or hail.
Daily weather in September for Thunder Bay
Click on any day in September to get detailed info about the usual weather on that day in Thunder Bay. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in Thunder Bay
Have you been to Thunder Bay in September?
Share your weather experience in September in Thunder Bay.
Average weather in Thunder Bay by month
Click on a month below to see detailed weather info for Thunder Bay. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
Or check out the climate of Thunder Bay for all months at once
