May is one of the warmer months of the year in Pasadena, with average highs near 28.2°C and lows around 21.6°C (mean 24.9°C). It is a relatively wet time of year, averaging 138 mm of rainfall and 79% relative humidity across the period.
May is one of the warmer months of the year in Pasadena. Across 45 years of records, the warmest May in Pasadena was 2022 — when the month averaged 27.4°C — while the coldest was 1993 at 22.7°C. Typical May days reach 28.2°C with nights near 21.6°C. The long-term trend is warming, about 0.3°C per decade.
May is a relatively wet time of year in Pasadena, averaging 138 mm of rainfall. The wettest May on record was 2021 with 354 mm, while the driest was 1998 at 2 mm.
Relative humidity in Pasadena during May averages 79%. The most humid May was 1991 at 88%, and the least humid was 2011 at 69%.
May receives about 5.9 kWh/m²/day of solar energy in Pasadena. The sunniest May was 2022 at 6.8 kWh/m²/day, and the cloudiest was 2024 at 4.8.
Average wind speed in Pasadena during May is 3.6 m/s. The windiest May was 2011 at 4.7 m/s, while the calmest was 2023 at 2.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 24.3°C | 24.6°C | 25.1°C | 25.1°C | 25.7°C | +1.4°C |
| Avg High | 27.7°C | 27.7°C | 28.4°C | 28.5°C | 28.9°C | +1.2°C |
| Avg Low | 20.9°C | 21.4°C | 21.7°C | 21.7°C | 22.6°C | +1.7°C |
| Avg Rain | 130 mm | 132 mm | 100 mm | 149 mm | 202 mm | +72 mm |
May temperatures in Pasadena have risen by about 1.8°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 9.5°C (2013) to a record high of 35.4°C (1998).
Rainfall in May is a relatively wet time of year, averaging 138 mm, with a wettest year of 354 mm.
One of the best times to visit Pasadena
May is one of the best times to visit Pasadena. Expect days averaging 28.2°C and nights around 21.6°C (mean 24.9°C) — warmer than Pasadena's yearly average — with higher rainfall (138 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 29.2°C | 25.8°C | 22.5°C | 32.3°C | 16.4°C | 186 mm | 80% | 3.6 m/s | 5.9 |
| 2024 | 28.7°C | 26.2°C | 23.8°C | 32.8°C | 21.0°C | 269 mm | 87% | 3.5 m/s | 4.8 |
| 2023 | 28.2°C | 25.2°C | 22.1°C | 30.4°C | 17.4°C | 162 mm | 81% | 2.6 m/s | 5.5 |
| 2022 🔥 | 31.2°C | 27.4°C | 23.5°C | 34.0°C | 20.6°C | 75 mm | 75% | 3.9 m/s | 6.8 |
| 2021 🌧️ | 27.4°C | 24.7°C | 22.0°C | 30.2°C | 17.2°C | 354 mm | 83% | 3.9 m/s | 5.1 |
| 2020 | 28.4°C | 24.9°C | 21.4°C | 31.4°C | 16.5°C | 165 mm | 79% | 3.5 m/s | 6.3 |
| 2019 | 28.0°C | 25.4°C | 22.8°C | 31.6°C | 17.3°C | 247 mm | 83% | 4.1 m/s | 5.4 |
| 2018 | 30.8°C | 26.8°C | 22.8°C | 34.0°C | 18.3°C | 54 mm | 73% | 3.2 m/s | 6.6 |
| 2017 | 28.2°C | 24.4°C | 20.7°C | 30.5°C | 14.0°C | 172 mm | 75% | 3.8 m/s | 6.3 |
| 2016 | 27.2°C | 24.4°C | 21.6°C | 29.2°C | 14.8°C | 263 mm | 84% | 3.3 m/s | 5.3 |
| 2015 | 27.2°C | 25.0°C | 22.7°C | 29.0°C | 15.3°C | 284 mm | 86% | 3.6 m/s | 4.9 |
| 2014 | 27.6°C | 23.8°C | 20.1°C | 30.1°C | 13.2°C | 170 mm | 74% | 4 m/s | 6 |
| 2013 | 27.2°C | 23.6°C | 20.0°C | 31.7°C | 9.5°C | 80 mm | 77% | 4 m/s | 6.1 |
| 2012 | 28.9°C | 25.4°C | 22.0°C | 32.5°C | 18.0°C | 116 mm | 77% | 3.1 m/s | 6.4 |
| 2011 | 29.8°C | 25.7°C | 21.5°C | 35.2°C | 13.3°C | 16 mm | 69% | 4.7 m/s | 6.5 |
| 2010 | 29.8°C | 26.1°C | 22.4°C | 34.2°C | 16.5°C | 87 mm | 76% | 3.4 m/s | 6.4 |
| 2009 | 28.5°C | 25.1°C | 21.6°C | 31.5°C | 15.5°C | 34 mm | 78% | 3.3 m/s | 6.1 |
| 2008 | 29.0°C | 25.4°C | 21.7°C | 32.2°C | 15.8°C | 61 mm | 76% | 3.9 m/s | 5.8 |
| 2007 | 26.6°C | 24.0°C | 21.3°C | 29.7°C | 17.6°C | 152 mm | 82% | 3.2 m/s | 5.6 |
| 2006 | 29.3°C | 25.5°C | 21.7°C | 32.1°C | 15.9°C | 114 mm | 74% | 3.6 m/s | 6.1 |
| 2005 | 28.2°C | 24.3°C | 20.5°C | 34.0°C | 12.6°C | 102 mm | 76% | 3 m/s | 6.3 |
| 2004 | 27.2°C | 24.2°C | 21.1°C | 31.7°C | 12.9°C | 172 mm | 83% | 3.9 m/s | 5.8 |
| 2003 | 29.9°C | 26.3°C | 22.6°C | 33.2°C | 19.2°C | 3 mm | 78% | 3.5 m/s | 5.9 |
| 2002 | 28.9°C | 25.4°C | 21.8°C | 31.2°C | 13.7°C | 83 mm | 74% | 4.2 m/s | 6.2 |
| 2001 | 28.2°C | 24.9°C | 21.7°C | 30.6°C | 16.5°C | 88 mm | 79% | 3.6 m/s | 6.2 |
| 2000 | 28.6°C | 25.7°C | 22.9°C | 32.1°C | 18.7°C | 191 mm | 82% | 3.8 m/s | 6 |
| 1999 | 29.0°C | 25.5°C | 21.9°C | 31.9°C | 16.2°C | 124 mm | 77% | 3.4 m/s | 6 |
| 1998 | 30.9°C | 26.4°C | 21.9°C | 35.4°C | 17.8°C | 2 mm | 75% | 3.4 m/s | 6.5 |
| 1997 | 26.3°C | 23.3°C | 20.3°C | 29.6°C | 14.2°C | 144 mm | 85% | 3 m/s | 5.6 |
| 1996 | 29.7°C | 26.1°C | 22.6°C | 34.0°C | 14.9°C | 20 mm | 78% | 4.4 m/s | 6.4 |
| 1995 | 28.1°C | 24.9°C | 21.7°C | 30.6°C | 14.5°C | 191 mm | 83% | 3.8 m/s | 5.8 |
| 1994 | 27.5°C | 24.4°C | 21.4°C | 30.9°C | 14.7°C | 160 mm | 80% | 2.9 m/s | 5.7 |
| 1993 ❄️ | 25.8°C | 22.7°C | 19.5°C | 29.2°C | 13.0°C | 168 mm | 83% | 3.5 m/s | 5.6 |
| 1992 | 25.7°C | 22.9°C | 20.1°C | 29.0°C | 11.9°C | 176 mm | 82% | 2.9 m/s | 5.3 |
| 1991 | 27.1°C | 24.7°C | 22.4°C | 30.6°C | 14.6°C | 212 mm | 88% | 3.6 m/s | 5.1 |
| 1990 | 27.1°C | 24.6°C | 22.1°C | 29.9°C | 15.6°C | 124 mm | 85% | 4 m/s | 5.5 |
| 1989 | 28.8°C | 25.5°C | 22.1°C | 31.6°C | 16.9°C | 187 mm | 82% | 3.8 m/s | 5.9 |
| 1988 | 28.2°C | 23.9°C | 19.5°C | 32.3°C | 15.1°C | 21 mm | 71% | 3.4 m/s | 6.2 |
| 1987 | 27.1°C | 24.4°C | 21.7°C | 29.4°C | 18.8°C | 160 mm | 84% | 2.7 m/s | 5.1 |
| 1986 | 27.5°C | 24.2°C | 20.8°C | 30.8°C | 15.0°C | 146 mm | 80% | 3.6 m/s | 5.5 |
| 1985 | 28.2°C | 24.7°C | 21.2°C | 32.7°C | 16.5°C | 67 mm | 76% | 3.1 m/s | 6.1 |
| 1984 | 28.0°C | 24.3°C | 20.7°C | 33.1°C | 13.8°C | 130 mm | 75% | 4 m/s | 5.8 |
| 1983 | 26.9°C | 23.6°C | 20.2°C | 29.9°C | 14.6°C | 142 mm | 80% | 3.7 m/s | — |
| 1982 | 26.8°C | 24.1°C | 21.3°C | 31.0°C | 14.4°C | 166 mm | 82% | 3.5 m/s | — |
| 1981 | 27.6°C | 24.0°C | 20.4°C | 31.5°C | 12.4°C | 155 mm | 77% | 3.7 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 28.2°C with lows near 21.6°C (mean 24.9°C), based on 45 years of NASA POWER data.
May averages 138 mm of rainfall in Pasadena, a relatively wet time of year. The wettest on record was 354 mm in 2021.
The hottest May reached 35.4°C in 1998. The coldest dipped to 9.5°C in 2013.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.8°C. Daytime highs moved from 27.5°C to 28.9°C and overnight lows from 20.8°C to 22.8°C over the same span.
May is one of the warmer months of the year in Pasadena and a relatively wet time of year, so plan for around 28.2°C daytime highs and 21.6°C at night.
Not quite — May is the 8th coolest month in Pasadena, averaging 24.9°C.
For May in Pasadena, pack light layers you can adjust through the day, with typical highs of 28.2°C and lows of 21.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 79% — quite humid.
Average wind speed in May is 3.6 m/s. The windiest May on record averaged 4.7 m/s (2011).
The wettest May on record was 2021 with 354 mm. On average, May sees 138 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 Pasadena 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.
