May is one of the warmer months of the year in Summerside, with average highs near 12.2°C and lows around 4.5°C (mean 8.4°C). It is about average for rainfall, averaging 81 mm of rainfall and 84% relative humidity across the period.
May is one of the warmer months of the year in Summerside. Across 45 years of records, the warmest Mays in Summerside were 1989 and 1998 — when the month averaged 10.8°C — while the coldest was 1990 at 6.4°C. Typical May days reach 12.2°C with nights near 4.5°C. The long-term May temperature trend is broadly flat.
May is about average for rainfall in Summerside, averaging 81 mm of rainfall. The wettest May on record was 1990 with 181 mm, while the driest was 1992 at 22 mm.
Relative humidity in Summerside during May averages 84%. The most humid May was 2011 at 90%, and the least humid was 1987 at 78%.
May receives about 5.2 kWh/m²/day of solar energy in Summerside. The sunniest May was 1999 at 6.3 kWh/m²/day, and the cloudiest was 1984 at 4.
Average wind speed in Summerside during May is 3.5 m/s. The windiest Mays were 2020 and 2023 at 4.2 m/s, while the calmest was 2006 at 2.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 8.6°C | 7.9°C | 8.0°C | 8.6°C | 8.6°C | 0°C |
| Avg High | 12.5°C | 12.0°C | 11.7°C | 12.3°C | 12.5°C | 0°C |
| Avg Low | 4.7°C | 3.9°C | 4.3°C | 4.9°C | 4.8°C | +0.1°C |
| Avg Rain | 91 mm | 74 mm | 87 mm | 78 mm | 76 mm | -15 mm |
May temperatures in Summerside have risen by about 0.4°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -2.7°C (1987) to a record high of 23.3°C (2023).
Rainfall in May is about average for rainfall, averaging 81 mm, with a wettest year of 181 mm.
A good time to visit Summerside
May is a good time to visit Summerside, with days averaging 12.2°C and nights around 4.5°C (mean 8.4°C, warmer than Summerside's yearly average) and higher rainfall. August and July 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 | 12.4°C | 8.7°C | 5.0°C | 22.2°C | 1.0°C | 99 mm | 85% | 3.8 m/s | 5 |
| 2024 | 12.9°C | 9.3°C | 5.7°C | 20.7°C | 0.6°C | 59 mm | 87% | 3.1 m/s | 5.5 |
| 2023 | 11.9°C | 8.1°C | 4.2°C | 23.3°C | 1.0°C | 62 mm | 81% | 4.2 m/s | 5.6 |
| 2022 | 13.3°C | 9.3°C | 5.3°C | 21.1°C | -0.6°C | 58 mm | 81% | 3.3 m/s | 6 |
| 2021 | 12.2°C | 8.3°C | 4.5°C | 20.0°C | 1.0°C | 91 mm | 81% | 3.9 m/s | 5.5 |
| 2020 | 12.0°C | 8.1°C | 4.2°C | 21.2°C | 0.2°C | 87 mm | 81% | 4.2 m/s | 5.5 |
| 2019 | 9.7°C | 6.5°C | 3.2°C | 16.3°C | -0.4°C | 89 mm | 85% | 3.6 m/s | 5 |
| 2018 | 12.7°C | 8.2°C | 3.7°C | 22.2°C | 0.1°C | 85 mm | 80% | 3.6 m/s | 6 |
| 2017 | 12.2°C | 8.5°C | 4.9°C | 21.9°C | 0.7°C | 142 mm | 87% | 3.9 m/s | 5 |
| 2016 | 12.8°C | 9.0°C | 5.2°C | 21.6°C | 0.4°C | 70 mm | 85% | 3.4 m/s | 4.9 |
| 2015 | 13.4°C | 9.3°C | 5.1°C | 21.9°C | -1.0°C | 59 mm | 83% | 3.5 m/s | 5.5 |
| 2014 | 10.8°C | 7.3°C | 3.8°C | 18.1°C | -0.4°C | 59 mm | 86% | 3.2 m/s | 5.1 |
| 2013 | 13.5°C | 9.6°C | 5.7°C | 21.2°C | 0.7°C | 69 mm | 85% | 3.7 m/s | 5 |
| 2012 | 14.3°C | 10.5°C | 6.7°C | 20.9°C | 0.6°C | 61 mm | 83% | 3.1 m/s | 5.3 |
| 2011 | 11.3°C | 8.3°C | 5.2°C | 19.7°C | 0.9°C | 99 mm | 90% | 4 m/s | 4.2 |
| 2010 | 12.6°C | 9.0°C | 5.5°C | 21.3°C | 1.8°C | 46 mm | 83% | 3.9 m/s | 5.5 |
| 2009 | 13.1°C | 9.2°C | 5.4°C | 19.3°C | 1.7°C | 79 mm | 83% | 3.4 m/s | 5.2 |
| 2008 | 11.5°C | 8.1°C | 4.7°C | 18.4°C | 0.8°C | 103 mm | 86% | 3.6 m/s | 4.8 |
| 2007 | 11.1°C | 7.5°C | 4.0°C | 20.6°C | 0.2°C | 90 mm | 83% | 3.4 m/s | 4.9 |
| 2006 | 13.8°C | 9.7°C | 5.5°C | 19.3°C | 1.4°C | 61 mm | 84% | 2.8 m/s | 5.5 |
| 2005 | 9.6°C | 6.7°C | 3.8°C | 17.9°C | -0.3°C | 125 mm | 87% | 3.9 m/s | 4.6 |
| 2004 | 12.2°C | 8.0°C | 3.8°C | 18.5°C | -0.5°C | 46 mm | 81% | 3.7 m/s | 4.8 |
| 2003 | 10.6°C | 7.0°C | 3.5°C | 20.6°C | -0.6°C | 78 mm | 86% | 3 m/s | 4.6 |
| 2002 | 12.1°C | 8.1°C | 4.1°C | 19.4°C | -1.7°C | 76 mm | 80% | 3.9 m/s | 5.9 |
| 2001 | 12.7°C | 8.7°C | 4.7°C | 21.5°C | -0.5°C | 86 mm | 85% | 3.1 m/s | 5.5 |
| 2000 | 10.8°C | 7.1°C | 3.5°C | 17.4°C | 0.0°C | 124 mm | 82% | 3.5 m/s | 4.8 |
| 1999 | 15.4°C | 10.5°C | 5.6°C | 21.8°C | -0.1°C | 28 mm | 80% | 3.3 m/s | 6.3 |
| 1998 | 15.0°C | 10.8°C | 6.5°C | 20.8°C | 1.5°C | 57 mm | 82% | 3.1 m/s | 5.5 |
| 1997 | 10.7°C | 7.1°C | 3.5°C | 16.4°C | 0.1°C | 52 mm | 83% | 3.9 m/s | 4.9 |
| 1996 | 11.1°C | 7.3°C | 3.5°C | 17.5°C | -0.7°C | 91 mm | 81% | 3.4 m/s | 4.8 |
| 1995 | 10.8°C | 6.9°C | 3.0°C | 16.4°C | -0.4°C | 58 mm | 83% | 3 m/s | 5.4 |
| 1994 | 10.4°C | 6.9°C | 3.4°C | 18.1°C | 0.6°C | 106 mm | 85% | 3.8 m/s | 4.8 |
| 1993 | 11.5°C | 7.5°C | 3.5°C | 18.1°C | -1.9°C | 60 mm | 84% | 3.4 m/s | 5.3 |
| 1992 | 12.2°C | 7.4°C | 2.7°C | 21.5°C | -1.7°C | 22 mm | 80% | 3.2 m/s | 5.2 |
| 1991 | 12.6°C | 8.3°C | 4.0°C | 18.5°C | -1.4°C | 82 mm | 81% | 3.6 m/s | 5.1 |
| 1990 ❄️ 🌧️ | 9.8°C | 6.4°C | 3.0°C | 19.5°C | 0.7°C | 181 mm | 85% | 4 m/s | 4.3 |
| 1989 🔥 | 15.0°C | 10.8°C | 6.7°C | 20.4°C | 2.5°C | 100 mm | 88% | 3 m/s | 4.6 |
| 1988 | 12.5°C | 8.6°C | 4.6°C | 18.2°C | 0.0°C | 84 mm | 87% | 3.6 m/s | 4.8 |
| 1987 | 12.8°C | 8.2°C | 3.7°C | 17.3°C | -2.7°C | 44 mm | 78% | 3.5 m/s | 5.7 |
| 1986 | 12.3°C | 8.3°C | 4.2°C | 19.3°C | -1.7°C | 62 mm | 83% | 3.5 m/s | 6.2 |
| 1985 | 11.3°C | 7.3°C | 3.4°C | 18.0°C | -0.9°C | 120 mm | 83% | 3.4 m/s | 5.4 |
| 1984 | 11.8°C | 8.3°C | 4.9°C | 18.3°C | 0.7°C | 112 mm | 88% | 3.6 m/s | 4 |
| 1983 | 11.7°C | 8.3°C | 4.8°C | 18.0°C | 0.7°C | 140 mm | 88% | 3.5 m/s | — |
| 1982 | 11.3°C | 7.4°C | 3.6°C | 20.6°C | 0.0°C | 64 mm | 84% | 3.5 m/s | — |
| 1981 | 14.0°C | 10.0°C | 6.1°C | 18.9°C | 0.2°C | 95 mm | 86% | 3.8 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 12.2°C with lows near 4.5°C (mean 8.4°C), based on 45 years of NASA POWER data.
May averages 81 mm of rainfall in Summerside, about average for rainfall. The wettest on record was 181 mm in 1990.
The hottest May reached 23.3°C in 2023. The coldest dipped to -2.7°C in 1987.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 0.4°C. Daytime highs moved from 12°C to 12.5°C and overnight lows from 4.6°C to 4.9°C over the same span.
May is one of the warmer months of the year in Summerside and about average for rainfall, so plan for around 12.2°C daytime highs and 4.5°C at night.
Not quite — May is the 7th coolest month in Summerside, averaging 8.4°C.
For May in Summerside, pack warm layers and a jacket for chilly mornings, with typical highs of 12.2°C and lows of 4.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 84% — quite humid.
Average wind speed in May is 3.5 m/s. The windiest May on record averaged 4.2 m/s (2020).
The wettest May on record was 1990 with 181 mm. On average, May sees 81 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 Summerside 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.
