Climate averages 1991–2020
Thunder Bay weather
in July.
A warm, moderately wet month: one of the warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
July is a warm month in Thunder Bay: daytime highs average 22.3°C and nights cool to about 15.3°C. By daytime temperature it is one of the warmest months of the year.
Expect about 76 mm of rain on roughly 11 days, which makes July a moderately wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 15 h 40 min on an average July day.
The nearest other city in this atlas is Duluth (278 km away). In July its highs average 23.9°C, 1.6°C warmer than Thunder Bay, with 98 mm of rain.
Among the 86 cities listed in Canada, Thunder Bay ranks 72nd of 86 for the warmest July highs and 32nd of 86 for the driest July (rainfall, lowest first). The mean July high of those 86 cities is 24.4°C; Thunder Bay is 2.0°C cooler than that mean.
From July to August, average highs fall by 0.1°C to 22.3°C, and monthly rainfall falls from 76 mm to 67 mm.
The annual picture
July in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Thunder Bay climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -9.6°C-16.6°C | -16.6°C | 29 | 6.5 | 8.89 h |
| February | -8.0°C-15.0°C | -15.0°C | 22 | 4.9 | 10.210 h |
| March | -1.7°C-8.7°C | -8.7°C | 31 | 6.8 | 11.912 h |
| April | 5.1°C-2.2°C | -2.2°C | 54 | 8.3 | 13.614 h |
| May | 12.5°C4.2°C | 4.2°C | 66 | 10.1 | 15.215 h |
| June | 18.3°C10.7°C | 10.7°C | 65 | 10.5 | 16.016 h |
| July, selected | 22.3°C15.3°C | 15.3°C | 76 | 10.6 | 15.716 h |
| August | 22.3°C15.6°C | 15.6°C | 67 | 9.1 | 14.314 h |
| September | 17.8°C11.7°C | 11.7°C | 84 | 10.5 | 12.613 h |
| October | 9.9°C4.8°C | 4.8°C | 72 | 10.4 | 10.911 h |
| November | 2.3°C-2.8°C | -2.8°C | 49 | 7.8 | 9.39 h |
| December | -4.8°C-11.3°C | -11.3°C | 38 | 7.4 | 8.48 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
July in nearby cities
- Duluth in JulyUnited States · 278 kmHigh 23.9°C · Low 17.8°C · 98 mm rain
- Sault Ste. Marie in JulyCanada · 424 kmHigh 23.3°C · Low 15.4°C · 101 mm rain
- Green Bay in JulyUnited States · 440 kmHigh 26.7°C · Low 17.8°C · 88 mm rain
- Appleton in JulyUnited States · 463 kmHigh 26.4°C · Low 17.7°C · 86 mm rain
- Brooklyn Park in JulyUnited States · 481 kmHigh 27.2°C · Low 18.5°C · 90 mm rain
- Saint Paul in JulyUnited States · 482 kmHigh 27.3°C · Low 18.6°C · 89 mm rain
- Minneapolis in JulyUnited States · 487 kmHigh 27.4°C · Low 18.6°C · 90 mm rain
- Plymouth, United States in JulyUnited States · 493 kmHigh 27.1°C · Low 18.5°C · 90 mm rain
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 limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Thunder Bay) is explained once on the Thunder Bay year overview and on the Sources, method and limits page.