May is one of the warmer months of the year in Casa Grande, with average highs near 34.9°C and lows around 17°C (mean 26°C). It is one of the drier months, averaging 5 mm of rainfall and 22% relative humidity across the period.
May is one of the warmer months of the year in Casa Grande. Across 45 years of records, the warmest May in Casa Grande was 1997 — when the month averaged 29.1°C — while the coldest was 1995 at 22.5°C. Typical May days reach 34.9°C with nights near 17°C. The long-term trend is warming, about 0.2°C per decade.
May is one of the drier months in Casa Grande, averaging 5 mm of rainfall. The wettest May on record was 1992 with 33 mm, while the driest were 2021, 2022 and 2024, among others at 0 mm.
Relative humidity in Casa Grande during May averages 22%. The most humid May was 1992 at 42%, and the least humid was 2002 at 15%.
May receives about 8.1 kWh/m²/day of solar energy in Casa Grande. The sunniest Mays were 2012, 2021 and 2022, among others at 8.6 kWh/m²/day, and the cloudiest was 1992 at 7.
Average wind speed in Casa Grande during May is 2.3 m/s. The windiest May was 1990 at 2.7 m/s, while the calmest were 1992, 1994 and 2009 at 1.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 25.8°C | 25.1°C | 26.9°C | 25.4°C | 26.8°C | +1°C |
| Avg High | 34.9°C | 34.0°C | 36.0°C | 34.1°C | 36.0°C | +1.1°C |
| Avg Low | 16.7°C | 16.3°C | 17.9°C | 16.6°C | 17.6°C | +0.9°C |
| Avg Rain | 6 mm | 7 mm | 5 mm | 4 mm | 2 mm | -4 mm |
May temperatures in Casa Grande have risen by about 0.7°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 6°C (1988) to a record high of 44.8°C (2020).
Rainfall in May is one of the drier months, averaging 5 mm, with a wettest year of 33 mm.
One of the best times to visit Casa Grande
May is one of the best times to visit Casa Grande. Expect days averaging 34.9°C and nights around 17°C (mean 26°C) — warmer than Casa Grande's yearly average — with low rainfall (5 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 | 35.1°C | 26.4°C | 17.6°C | 41.5°C | 11.3°C | 4 mm | 20% | 2.2 m/s | 7.9 |
| 2024 | 35.2°C | 26.2°C | 17.1°C | 41.1°C | 10.4°C | 0 mm | 21% | 2.1 m/s | 8.4 |
| 2023 | 34.9°C | 26.2°C | 17.4°C | 39.3°C | 11.1°C | 5 mm | 25% | 2.2 m/s | 8.2 |
| 2022 | 36.8°C | 27.1°C | 17.4°C | 41.5°C | 12.7°C | 0 mm | 15% | 2.5 m/s | 8.6 |
| 2021 | 36.1°C | 26.7°C | 17.4°C | 39.5°C | 13.0°C | 0 mm | 15% | 2.3 m/s | 8.6 |
| 2020 | 37.6°C | 28.3°C | 18.9°C | 44.8°C | 12.9°C | 1 mm | 20% | 2.2 m/s | 8.3 |
| 2019 | 30.7°C | 22.9°C | 15.2°C | 37.9°C | 11.0°C | 5 mm | 30% | 2.2 m/s | 7.8 |
| 2018 | 36.2°C | 27.0°C | 17.9°C | 41.6°C | 11.5°C | 1 mm | 18% | 2.3 m/s | 8.4 |
| 2017 | 34.9°C | 26.2°C | 17.4°C | 42.4°C | 11.7°C | 3 mm | 20% | 2.4 m/s | 8.1 |
| 2016 | 33.7°C | 25.1°C | 16.5°C | 40.2°C | 12.9°C | 4 mm | 24% | 2.2 m/s | 8.3 |
| 2015 | 31.8°C | 24.0°C | 16.3°C | 41.0°C | 11.0°C | 27 mm | 31% | 2.1 m/s | 7.8 |
| 2014 | 35.3°C | 26.4°C | 17.5°C | 42.0°C | 10.4°C | 0 mm | 17% | 2.5 m/s | 8.2 |
| 2013 | 35.8°C | 26.7°C | 17.6°C | 39.4°C | 14.2°C | 0 mm | 19% | 2.5 m/s | 8.3 |
| 2012 | 36.9°C | 27.5°C | 18.0°C | 43.0°C | 14.5°C | 2 mm | 15% | 2.4 m/s | 8.6 |
| 2011 | 33.1°C | 23.9°C | 14.7°C | 39.3°C | 8.9°C | 1 mm | 19% | 2.6 m/s | 8.5 |
| 2010 | 33.0°C | 23.8°C | 14.6°C | 38.7°C | 8.7°C | 0 mm | 22% | 2.3 m/s | 8.6 |
| 2009 | 37.1°C | 28.5°C | 20.0°C | 41.4°C | 17.1°C | 9 mm | 22% | 1.9 m/s | 7.6 |
| 2008 | 32.5°C | 23.9°C | 15.4°C | 42.3°C | 9.9°C | 27 mm | 25% | 2.4 m/s | 8.1 |
| 2007 | 35.9°C | 27.0°C | 18.2°C | 41.2°C | 10.4°C | 3 mm | 20% | 2 m/s | 8.3 |
| 2006 | 36.5°C | 27.4°C | 18.4°C | 40.7°C | 14.5°C | 0 mm | 16% | 2.1 m/s | 8.3 |
| 2005 | 34.9°C | 26.2°C | 17.6°C | 44.3°C | 12.0°C | 7 mm | 28% | 2 m/s | 8.1 |
| 2004 | 36.4°C | 26.9°C | 17.5°C | 40.0°C | 11.9°C | 1 mm | 17% | 2.4 m/s | 8.4 |
| 2003 | 35.7°C | 26.7°C | 17.8°C | 43.2°C | 10.8°C | 1 mm | 19% | 2.1 m/s | 8 |
| 2002 | 35.4°C | 25.9°C | 16.4°C | 43.2°C | 10.3°C | 0 mm | 15% | 2.2 m/s | 8.5 |
| 2001 | 37.9°C | 28.5°C | 19.2°C | 43.3°C | 11.0°C | 3 mm | 20% | 2.1 m/s | 8.2 |
| 2000 | 37.9°C | 28.3°C | 18.6°C | 44.6°C | 11.4°C | 1 mm | 16% | 2.3 m/s | 8.2 |
| 1999 | 34.2°C | 25.0°C | 15.8°C | 41.1°C | 8.2°C | 0 mm | 20% | 2.4 m/s | 8.4 |
| 1998 | 31.5°C | 22.8°C | 14.0°C | 37.7°C | 9.8°C | 1 mm | 35% | 2.3 m/s | 8.4 |
| 1997 🔥 | 37.9°C | 29.1°C | 20.2°C | 43.3°C | 13.7°C | 4 mm | 19% | 2.1 m/s | 8.1 |
| 1996 | 36.9°C | 27.3°C | 17.8°C | 43.9°C | 14.2°C | 0 mm | 16% | 2.5 m/s | 8.6 |
| 1995 ❄️ | 30.9°C | 22.5°C | 14.2°C | 38.0°C | 8.9°C | 2 mm | 31% | 2.3 m/s | 8 |
| 1994 | 33.5°C | 24.8°C | 16.1°C | 39.6°C | 11.6°C | 16 mm | 26% | 1.9 m/s | 7.3 |
| 1993 | 34.5°C | 25.7°C | 16.9°C | 39.3°C | 10.5°C | 7 mm | 34% | 2.2 m/s | 8.2 |
| 1992 🌧️ | 33.8°C | 25.9°C | 18.0°C | 38.4°C | 13.4°C | 33 mm | 42% | 1.9 m/s | 7 |
| 1991 | 32.8°C | 23.5°C | 14.1°C | 39.8°C | 8.2°C | 1 mm | 24% | 2.6 m/s | 7.6 |
| 1990 | 33.6°C | 24.7°C | 15.8°C | 39.8°C | 11.3°C | 4 mm | 21% | 2.7 m/s | 7.8 |
| 1989 | 35.8°C | 26.6°C | 17.4°C | 43.4°C | 11.4°C | 2 mm | 19% | 2.5 m/s | 8 |
| 1988 | 34.1°C | 25.0°C | 15.9°C | 41.3°C | 6.0°C | 0 mm | 23% | 2.4 m/s | 7.3 |
| 1987 | 33.4°C | 25.3°C | 17.2°C | 37.0°C | 10.6°C | 7 mm | 28% | 2.2 m/s | 7.5 |
| 1986 | 35.7°C | 26.3°C | 16.9°C | 41.8°C | 9.7°C | 3 mm | 18% | 2.3 m/s | 8.1 |
| 1985 | 35.5°C | 26.6°C | 17.7°C | 40.1°C | 11.7°C | 0 mm | 22% | 2.4 m/s | 7.8 |
| 1984 | 38.6°C | 28.9°C | 19.2°C | 44.6°C | 11.4°C | 9 mm | 20% | 2.2 m/s | 7.6 |
| 1983 | 33.7°C | 24.2°C | 14.7°C | 43.3°C | 8.1°C | 1 mm | 30% | 2.3 m/s | — |
| 1982 | 33.7°C | 24.6°C | 15.5°C | 39.3°C | 9.9°C | 19 mm | 26% | 2.3 m/s | — |
| 1981 | 33.7°C | 24.9°C | 16.1°C | 37.6°C | 11.5°C | 9 mm | 23% | 2.3 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 34.9°C with lows near 17°C (mean 26°C), based on 45 years of NASA POWER data.
May averages 5 mm of rainfall in Casa Grande, one of the drier months. The wettest on record was 33 mm in 1992.
The hottest May reached 44.8°C in 2020. The coldest dipped to 6°C in 1988.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 0.7°C. Daytime highs moved from 35°C to 35.6°C and overnight lows from 16.6°C to 17.4°C over the same span.
May is one of the warmer months of the year in Casa Grande and one of the drier months, so plan for around 34.9°C daytime highs and 17°C at night.
Not quite — May is the 8th coolest month in Casa Grande, averaging 26°C.
For May in Casa Grande, pack light, breathable clothing and sun protection, with typical highs of 34.9°C and lows of 17°C.
Relative humidity in May averages 22% — relatively dry.
Average wind speed in May is 2.3 m/s. The windiest May on record averaged 2.7 m/s (1990).
The wettest May on record was 1992 with 33 mm. On average, May sees 5 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 Casa Grande 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.
