Thunder Bay Weather in May
Average highs run from 12°C on May 1 to 18°C on May 31, and lows from 0°C to 6°C. Normal precipitation for the month is 68 mm over about 12 wet days.
May day by day
The normal high and low for each date, in °C.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
May at a glance
- Average high
- 15°C
- Average low
- 3°C
- Precipitation
- 68 mm
- Reanalysis high
- 28°CMay 10, 2007
- Reanalysis low
- -5°CMay 8, 2020
- Daylight
- 14 h 33 min to 15 h 48 min
- Cloud cover
- 72%
- Humidity
- 71%
- Dew point
- 3°C
- Wind
- 9.4 km/h
Every day of the month
A wet day has at least 1 mm of precipitation in the reanalysis.
| Date | Normal high | Normal low | Reanalysis high | Reanalysis low | Chance wet |
|---|---|---|---|---|---|
| May 1 | 12°C | 0°C | 22°C 1999 | -3°C 2002 | 34% |
| May 2 | 12°C | 0°C | 22°C 2012 | -4°C 1996 | 35% |
| May 3 | 12°C | 1°C | 21°C 2015 | -4°C 1996 | 36% |
| May 4 | 12°C | 1°C | 20°C 1993 | -5°C 2020 | 36% |
| May 5 | 13°C | 1°C | 22°C 1993 | -4°C 1992 | 37% |
| May 6 | 13°C | 1°C | 27°C 2016 | -2°C 1996 | 39% |
| May 7 | 13°C | 2°C | 24°C 1992 | -5°C 2020 | 40% |
| May 8 | 13°C | 2°C | 27°C 2007 | -5°C 2020 | 40% |
| May 9 | 13°C | 2°C | 26°C 2007 | -4°C 2010 | 39% |
| May 10 | 14°C | 2°C | 28°C 2007 | -4°C 2020 | 39% |
| May 11 | 14°C | 2°C | 25°C 1991 | -5°C 2020 | 40% |
| May 12 | 14°C | 2°C | 22°C 1991 | -4°C 2020 | 40% |
| May 13 | 14°C | 2°C | 22°C 2003 | -3°C 2013 | 40% |
| May 14 | 14°C | 3°C | 24°C 1991 | -3°C 2016 | 40% |
| May 15 | 14°C | 3°C | 28°C 1991 | -3°C 2004 | 42% |
| May 16 | 15°C | 3°C | 23°C 2010 | -2°C 2002 | 42% |
| May 17 | 15°C | 3°C | 23°C 2010 | -3°C 2002 | 43% |
| May 18 | 15°C | 3°C | 24°C 2010 | -3°C 2002 | 43% |
| May 19 | 15°C | 4°C | 26°C 2010 | -3°C 2002 | 44% |
| May 20 | 16°C | 4°C | 27°C 1994 | -2°C 2002 | 43% |
| May 21 | 16°C | 4°C | 25°C 1992 | -2°C 2002 | 42% |
| May 22 | 16°C | 4°C | 26°C 2018 | -1°C 1997 | 42% |
| May 23 | 17°C | 5°C | 24°C 2018 | -1°C 1992 | 43% |
| May 24 | 17°C | 5°C | 26°C 2015 | -1°C 2002 | 43% |
| May 25 | 17°C | 5°C | 27°C 2014 | 0°C 2013 | 44% |
| May 26 | 17°C | 5°C | 25°C 2014 | -2°C 2011 | 44% |
| May 27 | 17°C | 5°C | 25°C 2020 | 1°C 2008 | 44% |
| May 28 | 17°C | 6°C | 26°C 2018 | 0°C 2004 | 45% |
| May 29 | 18°C | 6°C | 28°C 1999 | 0°C 1996 | 44% |
| May 30 | 18°C | 6°C | 27°C 1995 | 1°C 1998 | 44% |
| May 31 | 18°C | 6°C | 28°C 1995 | 0°C 2015 | 44% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (EDT).
- May 1
- sunrise 6:38 AM, sunset 9:11 PM
- May 31
- sunrise 6:01 AM, sunset 9:49 PM
Other months
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-25. Sun and moon: computed with the NOAA solar equations and Meeus.