The best times to visit Thunder Bay for ideal weather are

June 11th to September 9th

based on average temperature and humidity from NOAA (the National Oceanic and Atmospheric Administration). Read below for more weather and travel details.



Other Thunder Bay Travel Info

Weather in Thunder Bay


Average temperatures in Thunder Bay vary an incredible amount. Considering humidity, temperatures feel cold for most of the year with a fair chance of precipitation about half of the year. The area is less temperate than some — in the 30th percentile for pleasant weather — compared to tourist destinations worldwide. Weeks with ideal weather are listed above. If you’re looking for the very warmest time to visit Thunder Bay, the hottest months are July, August, and then June. See average monthly temperatures below. The warmest time of year is generally early August where highs are regularly around 79.6°F (26.4°C) with temperatures rarely dropping below 52.9°F (11.6°C) at night.

Thunder Bay Temperatures (Fahrenheit)


Thunder Bay Temperatures (Celsius)


“Feels-Like” Temperatures

The way we experience weather isn’t all about temperature. Higher temperatures affect us much more at higher humidity, and colder temperatures feel piercing with high winds. Our perceived temperatures factor in humidity and wind chill to better represent how hot or cold the day feels to a person.

Thunder Bay Perceived Temperature (F)


Thunder Bay Perceived Temperature (C)



Average Thunder Bay Temperatures by Month

Daily highs (averaged for the month) usually give the best indication of the weather. A significantly lower mean and low generally just means it gets colder at night.

Show Fahrenheit

Month Avg. High (°F) Avg. Mean (°F) Avg. Low (°F)
Jan 19.8 8.6 -1.4
Feb 22 9.8 -1.7
Mar 37.1 24.3 12.9
Apr 49.9 36.9 24.9
May 63.3 49 36.2
Jun 72.6 58.4 45.6
Jul 78.5 64.8 52.1
Aug 77.8 63.8 50.3
Sep 69.3 55.1 43
Oct 54.1 43.2 33.1
Nov 39.7 29.9 21.5
Dec 24 14.5 5.7

Show Celsius

Month Avg. High (°C) Avg. Mean (°C) Avg. Low (°C)
Jan -6.8 -13 -18.6
Feb -5.6 -12.3 -18.7
Mar 2.8 -4.3 -10.6
Apr 9.9 2.7 -3.9
May 17.4 9.4 2.3
Jun 22.6 14.7 7.6
Jul 25.8 18.2 11.2
Aug 25.4 17.7 10.2
Sep 20.7 12.8 6.1
Oct 12.3 6.2 0.6
Nov 4.3 -1.2 -5.8
Dec -4.4 -9.7 -14.6



Precipitation (Rain or Snow)

If dry weather is what you’re after, the months with the lowest chance of significant precipitation in Thunder Bay are February, January, and then December. Note that we define “significant precipitation” as .1 inches or more in this section. The lowest chance of rain or snow occurs around late February and early March. For example, on the week of February 26th there are no days of precipitation on average. By contrast, it’s most likely to rain or snow in early June with an average of 2 days of significant precipitation the week of June 4th.

When can you find snow in Thunder Bay? Weather stations report very large amounts of snow likely to be deepest around February, especially close to late February and early March. The best time to ski (if at all) in Thunder Bay is often around around February 12th when fresh powder is deepest. Please note that a value of 0 for snow in the graph below may either mean there was no snow, or that snow is unreported.

Chance of Precipitation

The graph below shows the % chance of rainy and snowy days in Thunder Bay.

Days with precipitation

Snow on the Ground

The graph below shows the average snow on the ground in Thunder Bay (in).

Snow depth

Average Rain and Snow by Month

Show Inches

Month Daily Chance of Rain Average Snow Depth (in) Total Precipitation (in)
Jan 9% 8.1 1.1
Feb 7% 11.3 0.7
Mar 14% 10.1 1.9
Apr 17% 3.5 2.1
May 22% 0.7 3.3
Jun 26% 2 4.1
Jul 21% 5.8 2.9
Aug 18% 2 3.2
Sep 18% 1.8 2.7
Oct 14% 0.9 2
Nov 13% 2 1.6
Dec 13% 4.8 1.3

Show Centimeters

Month Daily Chance of Rain Average Snow Depth (cm) Total Precipitation (cm)
Jan 9 20.6 2.8
Feb 7 28.7 1.8
Mar 14 25.7 4.8
Apr 17 8.9 5.3
May 22 1.8 8.4
Jun 26 5.1 10.4
Jul 21 14.7 7.4
Aug 18 5.1 8.1
Sep 18 4.6 6.9
Oct 14 2.3 5.1
Nov 13 5.1 4.1
Dec 13 12.2 3.3


Humidity and Wind

Thunder Bay has some very humid months, with other comfortably humid months. The least humid month is April (53.3% relative humidity), and the most humid month is September (70%).

Wind in Thunder Bay is usually calm. The windiest month is May, followed by April and February. May’s average wind speed of around 7.2 knots (8.3 MPH or 13.4 KPH) is considered “a gentle breeze.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in mid May where average top sustained speeds reach 14.5 knots, which is considered a moderate breeze.

Relative Humidity (%)

The graph below shows the average % humidity by month in Thunder Bay.

Avg. Relative Humidity


The graph below shows wind speed (max and average) in knots.

Max Sustained Wind
Average Daily Wind

Average Wind Speeds

Show Wind Speeds

All wind speeds are in knots. 1 knot = 1.15 MPH or 1.85 KPH.

Month Avg. Wind Avg. Wind Feel Sustained High Wind High Wind Feel
Jan 6.5 Light breeze 11.6 Significant breeze
Feb 6.7 Light breeze 12 Significant breeze
Mar 6.6 Light breeze 12.4 Significant breeze
Apr 7.2 Gentle breeze 13.7 Significant breeze
May 7.2 Gentle breeze 13.6 Significant breeze
Jun 6.1 Light breeze 12.3 Significant breeze
Jul 5.8 Light breeze 11.6 Significant breeze
Aug 5.7 Light breeze 11.3 Significant breeze
Sep 5.6 Light breeze 11.3 Significant breeze
Oct 6.4 Light breeze 12 Significant breeze
Nov 6.2 Light breeze 11.6 Significant breeze
Dec 6.2 Light breeze 11 Significant breeze

Show Relative Humidity by Month

Month Avg. Relative Humidity
Jan 62.1%
Feb 56.3%
Mar 57.4%
Apr 53.3%
May 54.8%
Jun 63.6%
Jul 65.4%
Aug 66%
Sep 70%
Oct 69.4%
Nov 69.7%
Dec 69.2%


Is it Safe to Travel to Thunder Bay?



The Busiest and Least Crowded Months

The busiest month for tourism in Thunder Bay, ON, Canada is April, followed by June and May. Prices for hotels and flights will be most expensive during these months, though you can save if you purchase well in advance. Tourists are unlikely to visit Thunder Bay in November. Those willing to visit at these times will likely find it the least expensive month.

Estimated Tourism by Month


Most Popular Months to Visit

Tourists Seeking Accommodations

Tourism graph is based on Google searches for services used by tourists relative to the rest of the year. Tourism data for this area is extrapolated based on nearby areas. Displayed data is calculated relative to the peak, so a score of 54.2 in November means 54.2% of the tourists vs. April.



Overall Thunder Bay Travel Experience by Season

Spring (March through May)

Humidity and temperatures combine to make this season feel moderately cold. Highs range from 69.1°F (20.6°C) and 25.4°F (-3.7°C) with far warmer temperatures in the later months. Rain is somewhat common with 4 to 7 days of significant precipitation per month. Spring is the busiest for tourism, which makes it a good time for those looking for things to do.

Summer (June through August)

The middle-year months have comfortably cool weather with high temperatures that are comfortable. These months see the most precipitation with 5 to 8 days of precipitation per month. June – August is the second busiest season for tourism in Thunder Bay, so lodging and other accommodations may cost slightly more.

Fall (September through November)

Fall daily highs range from 73.1°F (22.8°C) and 29.3°F (-1.5°C), which will feel chilly given the humidity and wind. It rains or snows a significant amount: 4 to 5 days per month. Tourism is the slowest during these months due to the weather, so hotels may be affordably priced.

Winter (December through February)

Weather is far too cold this time of year in Thunder Bay to be enjoyable for warm weather travelers. The average high during this season is between 25.7°F (-3.5°C) and 16.8°F (-8.4°C). On average, it rains or snows a smalll amount: 2 to 4 times per month. These times of year are fairly slow with tourists.


Best Times to TravelCanada › Thunder Bay, ON, Canada