May is one of the warmer months of the year in Lethbridge, with average highs near 17.1°C and lows around 4.3°C (mean 10.7°C). It is a relatively wet time of year, averaging 63 mm of rainfall and 61% relative humidity across the period.
May is one of the warmer months of the year in Lethbridge. Across 45 years of records, the warmest May in Lethbridge was 2023 — when the month averaged 15.3°C — while the coldest was 1996 at 7.2°C. Typical May days reach 17.1°C with nights near 4.3°C. The long-term trend is warming, about 0.2°C per decade.
May is a relatively wet time of year in Lethbridge, averaging 63 mm of rainfall. The wettest May on record was 1981 with 149 mm, while the driest was 2001 at 16 mm.
Relative humidity in Lethbridge during May averages 61%. The most humid May was 1996 at 71%, and the least humid was 2001 at 48%.
May receives about 5.8 kWh/m²/day of solar energy in Lethbridge. The sunniest May was 2001 at 6.7 kWh/m²/day, and the cloudiest was 2010 at 5.
Average wind speed in Lethbridge during May is 2.6 m/s. The windiest May was 2001 at 3.5 m/s, while the calmest were 2014, 2015 and 2023, among others at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 10.8°C | 10.6°C | 10.5°C | 10.5°C | 11.5°C | +0.7°C |
| Avg High | 17.3°C | 17.1°C | 16.9°C | 16.8°C | 18.0°C | +0.7°C |
| Avg Low | 4.3°C | 4.1°C | 4.1°C | 4.2°C | 4.9°C | +0.6°C |
| Avg Rain | 63 mm | 73 mm | 55 mm | 69 mm | 50 mm | -13 mm |
May temperatures in Lethbridge have risen by about 1.7°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -5.3°C (2005) to a record high of 32.6°C (1986).
Rainfall in May is a relatively wet time of year, averaging 63 mm, with a wettest year of 149 mm.
A good time to visit Lethbridge
May is a good time to visit Lethbridge, with days averaging 17.1°C and nights around 4.3°C (mean 10.7°C, warmer than Lethbridge's yearly average) and moderate rainfall. July and August are marginally more temperate, but May still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 20.8°C | 13.6°C | 6.3°C | 31.9°C | 0.5°C | 42 mm | 56% | 2.5 m/s | 6.5 |
| 2024 | 16.1°C | 10.0°C | 4.0°C | 26.6°C | -2.7°C | 92 mm | 64% | 2.9 m/s | 5.4 |
| 2023 🔥 | 22.5°C | 15.3°C | 8.2°C | 29.8°C | 3.0°C | 35 mm | 57% | 2.1 m/s | 6.1 |
| 2022 | 15.9°C | 9.8°C | 3.7°C | 21.2°C | -1.8°C | 26 mm | 57% | 3.1 m/s | 5.7 |
| 2021 | 15.9°C | 9.8°C | 3.7°C | 26.7°C | -2.6°C | 35 mm | 59% | 2.5 m/s | 5.5 |
| 2020 | 16.6°C | 10.2°C | 3.7°C | 26.8°C | -3.6°C | 72 mm | 62% | 2.7 m/s | 5.6 |
| 2019 | 16.2°C | 10.1°C | 3.9°C | 27.1°C | -3.4°C | 101 mm | 64% | 2.2 m/s | 5.1 |
| 2018 | 20.9°C | 14.2°C | 7.6°C | 27.9°C | 1.2°C | 47 mm | 61% | 2.4 m/s | 6 |
| 2017 | 18.7°C | 12.2°C | 5.7°C | 27.5°C | -0.1°C | 55 mm | 61% | 2.6 m/s | 6.4 |
| 2016 | 17.6°C | 10.9°C | 4.3°C | 27.1°C | -1.6°C | 75 mm | 61% | 2.4 m/s | 5.7 |
| 2015 | 16.4°C | 9.9°C | 3.4°C | 25.4°C | -1.9°C | 45 mm | 61% | 2.1 m/s | 5.7 |
| 2014 | 16.0°C | 9.8°C | 3.5°C | 26.0°C | -3.5°C | 55 mm | 66% | 2.1 m/s | 5.7 |
| 2013 | 17.9°C | 11.6°C | 5.2°C | 26.6°C | -4.1°C | 67 mm | 60% | 2.6 m/s | 5.9 |
| 2012 | 16.1°C | 9.9°C | 3.8°C | 28.1°C | -2.5°C | 49 mm | 59% | 2.9 m/s | 5.9 |
| 2011 | 14.8°C | 8.5°C | 2.3°C | 20.2°C | -1.2°C | 89 mm | 66% | 2.8 m/s | 5.5 |
| 2010 | 13.4°C | 7.8°C | 2.2°C | 27.1°C | -4.0°C | 104 mm | 63% | 2.6 m/s | 5 |
| 2009 | 17.3°C | 10.5°C | 3.7°C | 29.0°C | -3.2°C | 36 mm | 58% | 2.8 m/s | 6.5 |
| 2008 | 17.2°C | 11.1°C | 4.9°C | 30.0°C | -2.4°C | 95 mm | 63% | 2.6 m/s | 5.2 |
| 2007 | 17.6°C | 11.2°C | 4.8°C | 25.6°C | 0.7°C | 79 mm | 62% | 2.6 m/s | 5.8 |
| 2006 | 18.5°C | 12.1°C | 5.6°C | 29.2°C | -3.0°C | 41 mm | 61% | 2.6 m/s | 6.4 |
| 2005 | 17.4°C | 10.7°C | 4.1°C | 22.8°C | -5.3°C | 35 mm | 59% | 2.6 m/s | 6.5 |
| 2004 | 14.7°C | 9.0°C | 3.4°C | 22.4°C | -3.1°C | 88 mm | 65% | 2.8 m/s | 5.2 |
| 2003 | 15.8°C | 9.7°C | 3.7°C | 28.4°C | -2.5°C | 50 mm | 64% | 2.6 m/s | 5.5 |
| 2002 | 14.1°C | 7.9°C | 1.6°C | 24.6°C | -5.0°C | 86 mm | 64% | 2.7 m/s | 5.5 |
| 2001 | 19.5°C | 12.4°C | 5.3°C | 30.5°C | -0.7°C | 16 mm | 48% | 3.5 m/s | 6.7 |
| 2000 | 16.9°C | 10.5°C | 4.2°C | 22.3°C | -1.8°C | 24 mm | 55% | 3 m/s | 6.2 |
| 1999 | 16.0°C | 9.8°C | 3.7°C | 28.4°C | -4.3°C | 46 mm | 56% | 3 m/s | 5.8 |
| 1998 | 19.9°C | 13.1°C | 6.2°C | 26.2°C | 2.5°C | 69 mm | 55% | 2.6 m/s | 6.5 |
| 1997 | 16.9°C | 10.3°C | 3.7°C | 26.2°C | -1.7°C | 105 mm | 65% | 2.6 m/s | 5.6 |
| 1996 ❄️ | 12.7°C | 7.2°C | 1.7°C | 19.9°C | -4.9°C | 92 mm | 71% | 2.3 m/s | 5.3 |
| 1995 | 16.0°C | 9.4°C | 2.8°C | 27.4°C | -3.6°C | 107 mm | 64% | 2.1 m/s | 5.6 |
| 1994 | 18.1°C | 11.7°C | 5.2°C | 26.0°C | 1.5°C | 64 mm | 62% | 2.5 m/s | 5.8 |
| 1993 | 19.8°C | 12.6°C | 5.4°C | 28.4°C | -0.4°C | 61 mm | 61% | 2.5 m/s | 6.1 |
| 1992 | 19.5°C | 12.1°C | 4.7°C | 28.8°C | -3.6°C | 39 mm | 53% | 2.8 m/s | 6.4 |
| 1991 | 16.4°C | 10.2°C | 3.9°C | 23.6°C | -5.0°C | 67 mm | 63% | 2.6 m/s | 5.5 |
| 1990 | 15.8°C | 9.5°C | 3.2°C | 25.2°C | -2.9°C | 81 mm | 65% | 2.5 m/s | 5.5 |
| 1989 | 16.6°C | 10.0°C | 3.4°C | 24.0°C | -1.2°C | 65 mm | 58% | 3 m/s | 5.8 |
| 1988 | 19.9°C | 12.9°C | 5.9°C | 29.9°C | -1.3°C | 35 mm | 52% | 3 m/s | 5.8 |
| 1987 | 19.5°C | 12.6°C | 5.8°C | 27.7°C | -2.1°C | 34 mm | 56% | 3.1 m/s | 6 |
| 1986 | 18.0°C | 11.5°C | 5.1°C | 32.6°C | -4.4°C | 69 mm | 63% | 2.6 m/s | 5.9 |
| 1985 | 19.1°C | 12.3°C | 5.5°C | 26.2°C | -0.6°C | 56 mm | 58% | 2.4 m/s | 6.3 |
| 1984 | 14.9°C | 8.9°C | 2.8°C | 26.9°C | -1.2°C | 62 mm | 62% | 3.2 m/s | 6.1 |
| 1983 | 16.7°C | 10.2°C | 3.7°C | 27.2°C | -4.3°C | 42 mm | 63% | 2.6 m/s | — |
| 1982 | 15.1°C | 8.5°C | 1.9°C | 24.6°C | -4.5°C | 58 mm | 64% | 2.6 m/s | — |
| 1981 🌧️ | 15.8°C | 10.1°C | 4.4°C | 22.3°C | -1.4°C | 149 mm | 70% | 2.4 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 17.1°C with lows near 4.3°C (mean 10.7°C), based on 45 years of NASA POWER data.
May averages 63 mm of rainfall in Lethbridge, a relatively wet time of year. The wettest on record was 149 mm in 1981.
The hottest May reached 32.6°C in 1986. The coldest dipped to -5.3°C in 2005.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.7°C. Daytime highs moved from 16.3°C to 18.2°C and overnight lows from 3.7°C to 5.2°C over the same span.
May is one of the warmer months of the year in Lethbridge and a relatively wet time of year, so plan for around 17.1°C daytime highs and 4.3°C at night.
Not quite — May is the 8th coolest month in Lethbridge, averaging 10.7°C.
For May in Lethbridge, pack warm layers and a jacket for chilly mornings, with typical highs of 17.1°C and lows of 4.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 61% — moderately humid.
Average wind speed in May is 2.6 m/s. The windiest May on record averaged 3.5 m/s (2001).
The wettest May on record was 1981 with 149 mm. On average, May sees 63 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 Lethbridge behaves each May, 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 May specifically, along with year-by-year records and how the month has changed over the decades.
