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.
Thunder Bay Travel Guide
Other Thunder Bay Travel Info
Weather in Thunder Bay
Temperature
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)
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Thunder Bay Temperatures (Celsius)
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“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)
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Thunder Bay Perceived Temperature (C)
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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.
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Snow on the Ground
The graph below shows the average snow on the ground in Thunder Bay (in).
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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.
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Wind
The graph below shows wind speed (max and average) in knots.
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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?
#N/A
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
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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 Travel› Canada › Thunder Bay, ON, Canada