Best time to visit Thunder Bay
The best time to visit Thunder Bay is June–August, judged on twenty years of weather records and the events worth going for.
Thunder Bay, Ontario, Canada
°C
mm
- Average daily high and low
- Precipitation
- Good month
- Best month
- Made good or best by an event
| Month | Average daily high | Average daily low | Precipitation | Verdict |
|---|---|---|---|---|
| January | -8.5 °C / 17 °F | -16.7 °C / 2 °F | 28 mm / 1.1 in | neither best nor good |
| February | -7.6 °C / 18 °F | -17.3 °C / 1 °F | 26 mm / 1 in | neither best nor good |
| March | 0 °C / 32 °F | -9.6 °C / 15 °F | 35 mm / 1.4 in | neither best nor good |
| April | 6.1 °C / 43 °F | -2.8 °C / 27 °F | 65 mm / 2.6 in | neither best nor good |
| May | 13.2 °C / 56 °F | 4 °C / 39 °F | 65 mm / 2.6 in | good month |
| June | 18.7 °C / 66 °F | 9.9 °C / 50 °F | 73 mm / 2.9 in | best month |
| July | 22.8 °C / 73 °F | 14.1 °C / 57 °F | 77 mm / 3 in | best month |
| August | 21.8 °C / 71 °F | 13.4 °C / 56 °F | 63 mm / 2.5 in | best month |
| September | 17.3 °C / 63 °F | 9.2 °C / 49 °F | 76 mm / 3 in | good month |
| October | 9.7 °C / 49 °F | 3.3 °C / 38 °F | 61 mm / 2.4 in | neither best nor good |
| November | 1.9 °C / 35 °F | -4 °C / 25 °F | 47 mm / 1.8 in | neither best nor good |
| December | -5.5 °C / 22 °F | -12.8 °C / 9 °F | 46 mm / 1.8 in | neither best nor good |
Good and best months depend on more than temperature, rain and events. How they are chosen
Each activity on this page has its own good and best months, rated on twenty years of daily weather records. Which measures count, and how much, depends on the activity: humidity for exploring outdoors, wind for the beach, hiking and skiing, snow for skiing alone. Between them, the activities are rated on:
- Daytime highs
- Night-time lows
- How warm it feels
- Humidity
- How much of the day is sunny
- Hours of daylight
- Monthly rainfall
- How many days it rains
- Days of heavy rain
- Wind
- Snowfall and days with snow
- Major events, such as festivals
The chart shows the good and best months for exploring outdoors.
The event icon marks a month that an event lifts to good or best, such as a festival or a natural spectacle. Choose “Weather only” in the toolbar to rate the months on weather alone.
Best months by activity
Exploring outdoors
Mild days and nights, mostly dry and bright. The default for 'when should I go'.
- JJanuary: neither
- FFebruary: neither
- MMarch: neither
- AApril: neither
- MMay: good
- JJune: best
- JJuly: best
- AAugust: best
- SSeptember: good
- OOctober: neither
- NNovember: neither
- DDecember: neither
- Best
- June–August
- Good
- May, September
Why these months
May · good
In its favour: share of daylight that is sunny 72%, precipitation 65 mm / 2.6 in, days with heavy rain 1.9 days, average daily high 13.2 °C / 56 °F, wet days 10.1 days, relative humidity 70%, average daily low 4 °C / 39 °F.
Against: feels like (high) 11.1 °C / 52 °F.
June · best
In its favour: feels like (high) 18.3 °C / 65 °F, average daily high 18.7 °C / 66 °F, share of daylight that is sunny 77%, precipitation 73 mm / 2.9 in, days with heavy rain 2.1 days, average daily low 9.9 °C / 50 °F, wet days 10.7 days, relative humidity 76%.
July · best
In its favour: feels like (high) 23.4 °C / 74 °F, average daily high 22.8 °C / 73 °F, share of daylight that is sunny 82%, precipitation 77 mm / 3 in, days with heavy rain 2.6 days, average daily low 14.1 °C / 57 °F, wet days 10.8 days, relative humidity 77%.
August · best
In its favour: feels like (high) 21.9 °C / 71 °F, average daily high 21.8 °C / 71 °F, share of daylight that is sunny 81%, precipitation 63 mm / 2.5 in, days with heavy rain 1.8 days, wet days 9.2 days, average daily low 13.4 °C / 56 °F.
Against: relative humidity 78%.
September · good
In its favour: feels like (high) 16.1 °C / 61 °F, share of daylight that is sunny 74%, average daily high 17.3 °C / 63 °F, precipitation 76 mm / 3 in, days with heavy rain 2.3 days, wet days 9.8 days, average daily low 9.2 °C / 49 °F.
Against: relative humidity 81%.
Hiking and trekking
Cool enough to climb in, dry enough to enjoy, long enough days.
- JJanuary: neither
- FFebruary: neither
- MMarch: neither
- AApril: neither
- MMay: best
- JJune: best
- JJuly: best
- AAugust: best
- SSeptember: best
- OOctober: best
- NNovember: neither
- DDecember: neither
- Best
- May–October
Why these months
May · best
In its favour: average daily high 13.2 °C / 56 °F, precipitation 65 mm / 2.6 in, days with heavy rain 1.9 days, feels like (high) 11.1 °C / 52 °F, average daily low 4 °C / 39 °F, share of daylight that is sunny 72%, daylight per day 15.2 h, wet days 10.1 days, wind (daily max) 17 km/h / 10 mph.
June · best
In its favour: average daily high 18.7 °C / 66 °F, precipitation 73 mm / 2.9 in, days with heavy rain 2.1 days, feels like (high) 18.3 °C / 65 °F, average daily low 9.9 °C / 50 °F, share of daylight that is sunny 77%, daylight per day 16 h, wet days 10.7 days, wind (daily max) 16 km/h / 10 mph.
July · best
In its favour: average daily high 22.8 °C / 73 °F, precipitation 77 mm / 3 in, share of daylight that is sunny 82%, daylight per day 15.6 h, average daily low 14.1 °C / 57 °F, days with heavy rain 2.6 days, wet days 10.8 days, feels like (high) 23.4 °C / 74 °F, wind (daily max) 16 km/h / 10 mph.
August · best
In its favour: average daily high 21.8 °C / 71 °F, precipitation 63 mm / 2.5 in, days with heavy rain 1.8 days, wet days 9.2 days, feels like (high) 21.9 °C / 71 °F, average daily low 13.4 °C / 56 °F, share of daylight that is sunny 81%, daylight per day 14.3 h, wind (daily max) 17 km/h / 10 mph.
September · best
In its favour: average daily high 17.3 °C / 63 °F, precipitation 76 mm / 3 in, days with heavy rain 2.3 days, feels like (high) 16.1 °C / 61 °F, average daily low 9.2 °C / 49 °F, share of daylight that is sunny 74%, daylight per day 12.6 h, wet days 9.8 days, wind (daily max) 18 km/h / 11 mph.
October · best
In its favour: precipitation 61 mm / 2.4 in, average daily high 9.7 °C / 49 °F, days with heavy rain 1.5 days, wet days 9.4 days, share of daylight that is sunny 62%, average daily low 3.3 °C / 38 °F, daylight per day 10.8 h, wind (daily max) 20 km/h / 12 mph, feels like (high) 6.5 °C / 44 °F.
An activity is listed only where it applies: skiing at ski destinations, beach and swimming at beach destinations. The nearest ski area is Mont Ste. Marie, 1045 km away.
Weather averages
Monthly averages over twenty years, 2006–2025. Highs, lows and precipitation are in the chart at the top.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels like (high) | -13.5 °C | -12.7 °C | -4.4 °C | 2.4 °C | 11.1 °C | 18.3 °C | 23.4 °C | 21.9 °C | 16.1 °C | 6.5 °C | -2.4 °C | -10.4 °C |
| Days with heavy rain | 0.3 days | 0.6 days | 0.9 days | 2.4 days | 1.9 days | 2.1 days | 2.6 days | 1.8 days | 2.3 days | 1.5 days | 1.4 days | 1.2 days |
| Time rain usually falls | 7 am | 3 am | 10 am | 7 pm | 1 am | 12 pm | 8 pm | 9 am | 2 am | 11 am | 3 am | 3 pm |
| Sunshine per day | 5.5 h | 7.6 h | 8.9 h | 9.9 h | 11.1 h | 12.3 h | 12.8 h | 11.5 h | 9.2 h | 6.7 h | 5 h | 4.6 h |
| Relative humidity | 77% | 72% | 70% | 69% | 70% | 76% | 77% | 78% | 81% | 80% | 80% | 80% |
Air quality
Averaged over a shorter period (2022–2025) than the twenty-year averages above, and not counted towards good or best months.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Air pollution (PM2.5) 2022–2025 | 2.2 µg/m³ | 4.4 µg/m³ | 5.2 µg/m³ | 7.2 µg/m³ | 7.5 µg/m³ | 12.2 µg/m³ | 12.1 µg/m³ | 8.7 µg/m³ | 5.6 µg/m³ | 3.6 µg/m³ | 2.7 µg/m³ | 2.3 µg/m³ |
| Air pollution (PM2.5, daily peak) 2022–2025 | 4.2 µg/m³ | 7.6 µg/m³ | 8.7 µg/m³ | 11.2 µg/m³ | 13.4 µg/m³ | 18.8 µg/m³ | 19.2 µg/m³ | 13.9 µg/m³ | 9.1 µg/m³ | 6.5 µg/m³ | 5.5 µg/m³ | 4.4 µg/m³ |
- Good 15 µg/m³ or less
- Fair 15 to 25 µg/m³
- Moderate 25 to 37.5 µg/m³
- Poor 37.5 to 50 µg/m³
- Very poor 50 to 75 µg/m³
- Extremely poor over 75 µg/m³
Each figure is compared with the World Health Organization's guideline for a day's air, 15 µg/m³ or less, and with its interim targets above that. The words are ours: the WHO does not name its steps. The figures are modelled monthly averages, so single days can be well above them. The daily peak is the average of each day's highest hour, shaded on the same scale.