May is one of the warmer months of the year in Markham, with average highs near 18°C and lows around 6.5°C (mean 12.3°C). It is about average for rainfall, averaging 61 mm of rainfall and 73% relative humidity across the period.
May is one of the warmer months of the year in Markham. Across 45 years of records, the warmest May in Markham was 1998 — when the month averaged 15.9°C — while the coldest was 1997 at 8°C. Typical May days reach 18°C with nights near 6.5°C. The long-term trend is warming, about 0.2°C per decade.
May is about average for rainfall in Markham, averaging 61 mm of rainfall. The wettest May on record was 2002 with 119 mm, while the driest was 2005 at 18 mm.
Relative humidity in Markham during May averages 73%. The most humid May was 2011 at 85%, and the least humid were 1987 and 1988 at 62%.
May receives about 5.5 kWh/m²/day of solar energy in Markham. The sunniest May was 2023 at 6.3 kWh/m²/day, and the cloudiest was 1984 at 4.4.
Average wind speed in Markham during May is 2.9 m/s. The windiest May was 1997 at 3.6 m/s, while the calmest was 2007 at 2.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 12.3°C | 12.1°C | 11.2°C | 12.9°C | 12.8°C | +0.5°C |
| Avg High | 18.1°C | 18.1°C | 16.8°C | 18.6°C | 18.6°C | +0.5°C |
| Avg Low | 6.5°C | 6.1°C | 5.7°C | 7.2°C | 7.0°C | +0.5°C |
| Avg Rain | 53 mm | 59 mm | 83 mm | 59 mm | 41 mm | -12 mm |
May temperatures in Markham have risen by about 2.1°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -3.2°C (2020) to a record high of 31.9°C (2012).
Rainfall in May is about average for rainfall, averaging 61 mm, with a wettest year of 119 mm.
A good time to visit Markham
May is a good time to visit Markham, with days averaging 18°C and nights around 6.5°C (mean 12.3°C, warmer than Markham'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 | 17.2°C | 12.0°C | 6.8°C | 25.5°C | 1.5°C | 68 mm | 75% | 3.3 m/s | 5 |
| 2024 | 20.7°C | 15.0°C | 9.4°C | 27.9°C | 4.8°C | 44 mm | 74% | 2.6 m/s | 5.7 |
| 2023 | 18.9°C | 12.5°C | 6.1°C | 30.7°C | 0.6°C | 29 mm | 66% | 2.4 m/s | 6.3 |
| 2022 | 19.6°C | 13.6°C | 7.6°C | 29.6°C | 1.1°C | 43 mm | 73% | 2.7 m/s | 5.7 |
| 2021 | 18.7°C | 12.6°C | 6.5°C | 29.3°C | -1.4°C | 22 mm | 64% | 2.8 m/s | 5.7 |
| 2020 | 16.2°C | 10.9°C | 5.6°C | 29.3°C | -3.2°C | 40 mm | 72% | 3.1 m/s | 5.4 |
| 2019 | 15.5°C | 10.1°C | 4.8°C | 22.5°C | 0.5°C | 69 mm | 82% | 2.9 m/s | 4.6 |
| 2018 | 21.2°C | 14.4°C | 7.7°C | 28.9°C | 0.5°C | 48 mm | 75% | 2.7 m/s | 6.1 |
| 2017 | 15.3°C | 10.8°C | 6.4°C | 25.4°C | 0.1°C | 119 mm | 82% | 3.1 m/s | 5 |
| 2016 | 18.5°C | 12.6°C | 6.8°C | 29.1°C | -0.5°C | 37 mm | 74% | 2.5 m/s | 6 |
| 2015 | 20.9°C | 14.5°C | 8.0°C | 27.0°C | -0.6°C | 37 mm | 69% | 2.9 m/s | 5.8 |
| 2014 | 17.6°C | 12.1°C | 6.5°C | 25.3°C | 0.8°C | 49 mm | 78% | 2.7 m/s | 5.4 |
| 2013 | 19.1°C | 13.3°C | 7.5°C | 28.0°C | 1.1°C | 61 mm | 73% | 2.9 m/s | 6.1 |
| 2012 | 21.2°C | 15.0°C | 8.8°C | 31.9°C | 3.1°C | 35 mm | 69% | 2.5 m/s | 6 |
| 2011 | 16.8°C | 12.0°C | 7.2°C | 27.2°C | 1.5°C | 84 mm | 85% | 2.8 m/s | 4.5 |
| 2010 | 20.2°C | 14.3°C | 8.5°C | 30.5°C | -0.8°C | 56 mm | 71% | 2.9 m/s | 5.7 |
| 2009 | 17.0°C | 11.0°C | 5.0°C | 23.8°C | -0.7°C | 62 mm | 75% | 3.1 m/s | 6.1 |
| 2008 | 15.2°C | 10.0°C | 4.7°C | 22.4°C | -0.2°C | 76 mm | 77% | 3.2 m/s | 5.3 |
| 2007 | 19.0°C | 12.7°C | 6.4°C | 29.0°C | 0.5°C | 56 mm | 71% | 2.2 m/s | 6.2 |
| 2006 | 18.4°C | 13.1°C | 7.8°C | 30.6°C | 0.4°C | 61 mm | 75% | 2.8 m/s | 5.5 |
| 2005 | 16.4°C | 10.7°C | 5.0°C | 24.5°C | -1.2°C | 18 mm | 71% | 2.4 m/s | 5.9 |
| 2004 | 16.5°C | 11.1°C | 5.7°C | 24.3°C | -3.0°C | 108 mm | 84% | 2.9 m/s | 4.9 |
| 2003 | 15.1°C | 10.2°C | 5.4°C | 20.7°C | 0.6°C | 111 mm | 81% | 3 m/s | 4.8 |
| 2002 🌧️ | 13.9°C | 8.7°C | 3.4°C | 23.1°C | -1.4°C | 119 mm | 79% | 3.4 m/s | 5.1 |
| 2001 | 18.4°C | 12.7°C | 7.0°C | 25.1°C | 0.8°C | 102 mm | 75% | 2.9 m/s | 5.6 |
| 2000 | 17.7°C | 12.2°C | 6.8°C | 25.8°C | 1.4°C | 115 mm | 79% | 3 m/s | 4.9 |
| 1999 | 20.4°C | 14.0°C | 7.5°C | 30.5°C | 2.6°C | 52 mm | 66% | 2.8 m/s | 6.1 |
| 1998 🔥 | 22.0°C | 15.9°C | 9.7°C | 29.5°C | 4.5°C | 41 mm | 69% | 2.8 m/s | 5.8 |
| 1997 ❄️ | 13.2°C | 8.0°C | 2.7°C | 20.6°C | -1.9°C | 59 mm | 76% | 3.6 m/s | 4.9 |
| 1996 | 15.8°C | 10.0°C | 4.3°C | 25.4°C | -2.2°C | 70 mm | 72% | 2.7 m/s | 5.6 |
| 1995 | 18.5°C | 12.3°C | 6.0°C | 27.5°C | -0.8°C | 37 mm | 65% | 3.1 m/s | 5.4 |
| 1994 | 16.8°C | 10.8°C | 4.7°C | 28.9°C | -0.8°C | 92 mm | 71% | 3.1 m/s | 5.3 |
| 1993 | 18.2°C | 12.0°C | 5.8°C | 28.1°C | 1.6°C | 56 mm | 68% | 3.1 m/s | 5.1 |
| 1992 | 18.3°C | 12.0°C | 5.7°C | 27.9°C | 0.9°C | 46 mm | 67% | 2.4 m/s | 6.1 |
| 1991 | 21.1°C | 15.2°C | 9.2°C | 27.9°C | -0.6°C | 66 mm | 74% | 2.8 m/s | 5.5 |
| 1990 | 16.7°C | 11.0°C | 5.3°C | 24.1°C | -0.5°C | 74 mm | 68% | 3.2 m/s | 5 |
| 1989 | 18.4°C | 12.7°C | 6.9°C | 27.1°C | 0.4°C | 45 mm | 68% | 3.1 m/s | 4.9 |
| 1988 | 21.0°C | 14.4°C | 7.8°C | 30.8°C | 0.7°C | 32 mm | 62% | 2.9 m/s | 5.8 |
| 1987 | 21.2°C | 14.6°C | 8.1°C | 31.1°C | -0.6°C | 22 mm | 62% | 3.1 m/s | 5.9 |
| 1986 | 19.8°C | 14.0°C | 8.2°C | 28.7°C | -3.1°C | 43 mm | 72% | 3.1 m/s | 5.4 |
| 1985 | 18.0°C | 12.3°C | 6.6°C | 23.6°C | 0.1°C | 58 mm | 76% | 3 m/s | 5.7 |
| 1984 | 14.0°C | 8.9°C | 3.7°C | 22.8°C | -2.4°C | 60 mm | 79% | 3.3 m/s | 4.4 |
| 1983 | 14.0°C | 8.7°C | 3.4°C | 19.5°C | -2.3°C | 92 mm | 81% | 3.2 m/s | — |
| 1982 | 19.6°C | 13.8°C | 8.0°C | 25.4°C | 3.0°C | 47 mm | 76% | 2.4 m/s | — |
| 1981 | 17.3°C | 11.5°C | 5.6°C | 25.8°C | -1.0°C | 77 mm | 71% | 2.7 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 18°C with lows near 6.5°C (mean 12.3°C), based on 45 years of NASA POWER data.
May averages 61 mm of rainfall in Markham, about average for rainfall. The wettest on record was 119 mm in 2002.
The hottest May reached 31.9°C in 2012. The coldest dipped to -3.2°C in 2020.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 2.1°C. Daytime highs moved from 16.6°C to 19°C and overnight lows from 5.5°C to 7.3°C over the same span.
May is one of the warmer months of the year in Markham and about average for rainfall, so plan for around 18°C daytime highs and 6.5°C at night.
Not quite — May is the 8th coolest month in Markham, averaging 12.3°C.
For May in Markham, pack warm layers and a jacket for chilly mornings, with typical highs of 18°C and lows of 6.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 73% — moderately humid.
Average wind speed in May is 2.9 m/s. The windiest May on record averaged 3.6 m/s (1997).
The wettest May on record was 2002 with 119 mm. On average, May sees 61 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 Markham 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.
