July is one of the warmer months of the year in Thunder Bay, with average highs near 23.3°C and lows around 12°C (mean 17.7°C). It is a relatively wet time of year, averaging 76 mm of rainfall and 75% relative humidity across the period.
July is one of the warmer months of the year in Thunder Bay. Across 45 years of records, the warmest July in Thunder Bay was 2012 — when the month averaged 20.7°C — while the coldest were 1992 and 2009 at 14.3°C. Typical July days reach 23.3°C with nights near 12°C. The long-term trend is warming, about 0.4°C per decade.
July is a relatively wet time of year in Thunder Bay, averaging 76 mm of rainfall. The wettest July on record was 1982 with 175 mm, while the driest was 2021 at 17 mm.
Relative humidity in Thunder Bay during July averages 75%. The most humid July was 1982 at 82%, and the least humid was 2021 at 61%.
July receives about 5.7 kWh/m²/day of solar energy in Thunder Bay. The sunniest July was 2005 at 6.7 kWh/m²/day, and the cloudiest was 1992 at 4.6.
Average wind speed in Thunder Bay during July is 0.5 m/s. The windiest Julys were 2022, 2024 and 2025, among others at 0.5 m/s, while the calmest were 2017, 2019 and 2023, among others at 0.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 17.6°C | 16.7°C | 17.3°C | 18.2°C | 18.8°C | +1.2°C |
| Avg High | 23.2°C | 22.2°C | 23.0°C | 23.8°C | 24.6°C | +1.4°C |
| Avg Low | 12.0°C | 11.1°C | 11.6°C | 12.6°C | 13.1°C | +1.1°C |
| Avg Rain | 78 mm | 85 mm | 70 mm | 78 mm | 67 mm | -11 mm |
July temperatures in Thunder Bay have risen by about 1.5°C between 1981–1985 and 2021–2025.
July has ranged from a record low of 4°C (1983) to a record high of 35°C (2021).
Rainfall in July is a relatively wet time of year, averaging 76 mm, with a wettest year of 175 mm.
One of the best times to visit Thunder Bay
July is one of the best times to visit Thunder Bay. Expect days averaging 23.3°C and nights around 12°C (mean 17.7°C) — warmer than Thunder Bay's yearly average — with moderate rainfall (76 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 23.6°C | 18.1°C | 12.6°C | 28.4°C | 9.4°C | 134 mm | 76% | 0.5 m/s | 5.5 |
| 2024 | 24.7°C | 19.3°C | 13.9°C | 30.3°C | 9.5°C | 48 mm | 76% | 0.5 m/s | 5.8 |
| 2023 | 23.3°C | 17.6°C | 11.8°C | 32.6°C | 8.3°C | 43 mm | 73% | 0.4 m/s | 5.7 |
| 2022 | 23.2°C | 17.4°C | 11.7°C | 30.2°C | 8.0°C | 85 mm | 76% | 0.5 m/s | 5.7 |
| 2021 | 26.9°C | 20.4°C | 13.9°C | 35.0°C | 9.2°C | 17 mm | 61% | 0.5 m/s | 6 |
| 2020 | 25.9°C | 20.2°C | 14.5°C | 32.3°C | 10.2°C | 71 mm | 74% | 0.5 m/s | 6 |
| 2019 | 25.0°C | 18.8°C | 12.5°C | 28.4°C | 8.2°C | 61 mm | 71% | 0.4 m/s | 6.3 |
| 2018 | 24.9°C | 19.2°C | 13.5°C | 30.6°C | 10.5°C | 87 mm | 74% | 0.5 m/s | 5.8 |
| 2017 | 22.9°C | 17.2°C | 11.6°C | 29.5°C | 7.6°C | 74 mm | 78% | 0.4 m/s | 5.9 |
| 2016 | 23.7°C | 18.4°C | 13.1°C | 29.8°C | 8.4°C | 68 mm | 76% | 0.5 m/s | 6.2 |
| 2015 | 23.4°C | 17.8°C | 12.2°C | 31.3°C | 7.7°C | 48 mm | 77% | 0.5 m/s | 5.7 |
| 2014 | 21.1°C | 15.9°C | 10.7°C | 30.4°C | 7.6°C | 109 mm | 80% | 0.5 m/s | 5.5 |
| 2013 | 21.8°C | 16.3°C | 10.9°C | 29.1°C | 6.0°C | 109 mm | 80% | 0.5 m/s | 5.1 |
| 2012 🔥 | 26.5°C | 20.7°C | 14.9°C | 29.9°C | 11.2°C | 61 mm | 72% | 0.5 m/s | 6.3 |
| 2011 | 23.5°C | 18.0°C | 12.6°C | 31.5°C | 7.8°C | 111 mm | 79% | 0.4 m/s | 5.8 |
| 2010 | 25.4°C | 19.9°C | 14.4°C | 29.4°C | 8.7°C | 47 mm | 72% | 0.5 m/s | 5.9 |
| 2009 | 19.2°C | 14.3°C | 9.3°C | 22.9°C | 6.1°C | 70 mm | 80% | 0.5 m/s | 5.6 |
| 2008 | 21.5°C | 16.2°C | 10.9°C | 26.6°C | 7.0°C | 77 mm | 81% | 0.5 m/s | 5.9 |
| 2007 | 25.1°C | 19.0°C | 13.0°C | 33.4°C | 7.2°C | 58 mm | 70% | 0.4 m/s | 5.9 |
| 2006 | 26.4°C | 20.4°C | 14.4°C | 32.4°C | 8.6°C | 77 mm | 67% | 0.5 m/s | 6.3 |
| 2005 | 24.7°C | 18.5°C | 12.4°C | 30.6°C | 8.3°C | 50 mm | 72% | 0.5 m/s | 6.7 |
| 2004 | 22.0°C | 16.2°C | 10.4°C | 27.7°C | 7.1°C | 79 mm | 77% | 0.4 m/s | 5.5 |
| 2003 | 22.4°C | 16.7°C | 11.0°C | 28.5°C | 7.1°C | 116 mm | 77% | 0.4 m/s | 5.8 |
| 2002 | 25.7°C | 19.2°C | 12.8°C | 32.4°C | 8.0°C | 43 mm | 73% | 0.4 m/s | 6.2 |
| 2001 | 20.8°C | 15.6°C | 10.4°C | 27.9°C | 5.2°C | 85 mm | 80% | 0.4 m/s | 5.5 |
| 2000 | 22.2°C | 16.7°C | 11.2°C | 29.3°C | 6.3°C | 44 mm | 75% | 0.5 m/s | 5.8 |
| 1999 | 23.4°C | 18.1°C | 12.8°C | 31.1°C | 8.5°C | 126 mm | 79% | 0.4 m/s | 6 |
| 1998 | 25.1°C | 19.0°C | 13.0°C | 31.6°C | 9.5°C | 54 mm | 66% | 0.5 m/s | 6.4 |
| 1997 | 21.9°C | 16.3°C | 10.6°C | 27.6°C | 4.2°C | 89 mm | 76% | 0.4 m/s | 6.2 |
| 1996 | 19.8°C | 14.9°C | 9.9°C | 27.9°C | 6.3°C | 125 mm | 79% | 0.5 m/s | 5.1 |
| 1995 | 23.9°C | 17.8°C | 11.7°C | 30.7°C | 5.5°C | 78 mm | 70% | 0.5 m/s | 5.3 |
| 1994 | 22.2°C | 16.4°C | 10.6°C | 28.2°C | 5.6°C | 48 mm | 74% | 0.4 m/s | 5.2 |
| 1993 | 21.5°C | 16.1°C | 10.8°C | 27.0°C | 7.7°C | 111 mm | 77% | 0.4 m/s | 4.8 |
| 1992 ❄️ | 19.6°C | 14.3°C | 9.0°C | 24.9°C | 5.9°C | 72 mm | 77% | 0.5 m/s | 4.6 |
| 1991 | 22.0°C | 17.0°C | 12.0°C | 30.9°C | 7.1°C | 86 mm | 74% | 0.5 m/s | 5.9 |
| 1990 | 22.9°C | 16.8°C | 10.7°C | 29.1°C | 6.8°C | 65 mm | 73% | 0.4 m/s | 5.8 |
| 1989 | 25.1°C | 18.7°C | 12.2°C | 29.3°C | 7.5°C | 22 mm | 71% | 0.4 m/s | 6.1 |
| 1988 | 26.0°C | 19.5°C | 13.0°C | 33.0°C | 8.9°C | 49 mm | 63% | 0.4 m/s | 5.9 |
| 1987 | 23.2°C | 17.9°C | 12.5°C | 31.2°C | 6.7°C | 107 mm | 77% | 0.5 m/s | 5 |
| 1986 | 21.8°C | 16.8°C | 11.8°C | 30.2°C | 8.2°C | 72 mm | 79% | 0.4 m/s | 5.4 |
| 1985 | 21.0°C | 15.6°C | 10.2°C | 24.4°C | 6.1°C | 97 mm | 78% | 0.4 m/s | 5.6 |
| 1984 | 22.2°C | 16.9°C | 11.6°C | 26.3°C | 7.1°C | 92 mm | 77% | 0.5 m/s | 5.4 |
| 1983 | 24.7°C | 19.0°C | 13.4°C | 32.0°C | 4.0°C | 56 mm | 78% | 0.4 m/s | — |
| 1982 🌧️ | 21.7°C | 16.7°C | 11.7°C | 26.1°C | 8.4°C | 175 mm | 82% | 0.4 m/s | — |
| 1981 | 23.1°C | 17.3°C | 11.5°C | 30.1°C | 5.1°C | 31 mm | 75% | 0.4 m/s | — |
Actual recorded July data for each year, 1981–2025 — sourced from NASA POWER.
The average high in July is around 23.3°C with lows near 12°C (mean 17.7°C), based on 45 years of NASA POWER data.
July averages 76 mm of rainfall in Thunder Bay, a relatively wet time of year. The wettest on record was 175 mm in 1982.
The hottest July reached 35°C in 2021. The coldest dipped to 4°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average July temperatures have risen by about 1.5°C. Daytime highs moved from 22.5°C to 24.3°C and overnight lows from 11.7°C to 12.8°C over the same span.
July is one of the warmer months of the year in Thunder Bay and a relatively wet time of year, so plan for around 23.3°C daytime highs and 12°C at night.
Not quite — July is the 11th coolest month in Thunder Bay, averaging 17.7°C.
For July in Thunder Bay, pack light layers you can adjust through the day, with typical highs of 23.3°C and lows of 12°C. Bring an umbrella or light rain jacket too.
Relative humidity in July averages 75% — moderately humid.
Average wind speed in July is 0.5 m/s. The windiest July on record averaged 0.5 m/s (1984).
The wettest July on record was 1982 with 175 mm. On average, July sees 76 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Thunder Bay behaves each July, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for July specifically, along with year-by-year records and how the month has changed over the decades.
