May is one of the warmer months of the year in Katy, with average highs near 30.1°C and lows around 19.3°C (mean 24.7°C). It is a relatively wet time of year, averaging 134 mm of rainfall and 77% relative humidity across the period.
May is one of the warmer months of the year in Katy. Across 45 years of records, the warmest May in Katy was 2022 — when the month averaged 27.9°C — while the coldest was 1993 at 21.9°C. Typical May days reach 30.1°C with nights near 19.3°C. The long-term trend is warming, about 0.5°C per decade.
May is a relatively wet time of year in Katy, averaging 134 mm of rainfall. The wettest May on record was 2015 with 327 mm, while the driest was 1998 at 2 mm.
Relative humidity in Katy during May averages 77%. The most humid May was 2015 at 87%, and the least humid was 2011 at 60%.
May receives about 5.9 kWh/m²/day of solar energy in Katy. The sunniest May was 2022 at 6.8 kWh/m²/day, and the cloudiest was 2024 at 4.8.
Average wind speed in Katy during May is 2 m/s. The windiest May was 2011 at 2.9 m/s, while the calmest was 2023 at 1.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 23.9°C | 24.4°C | 24.9°C | 25.1°C | 25.7°C | +1.8°C |
| Avg High | 29.3°C | 29.5°C | 30.4°C | 30.8°C | 31.0°C | +1.7°C |
| Avg Low | 18.5°C | 19.2°C | 19.5°C | 19.5°C | 20.4°C | +1.9°C |
| Avg Rain | 147 mm | 129 mm | 101 mm | 143 mm | 160 mm | +13 mm |
May temperatures in Katy have risen by about 2.2°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 6.3°C (2013) to a record high of 40.6°C (1998).
Rainfall in May is a relatively wet time of year, averaging 134 mm, with a wettest year of 327 mm.
One of the best times to visit Katy
May is one of the best times to visit Katy. Expect days averaging 30.1°C and nights around 19.3°C (mean 24.7°C) — warmer than Katy's yearly average — with higher rainfall (134 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 | 32.0°C | 26.3°C | 20.5°C | 37.3°C | 13.1°C | 139 mm | 74% | 2.1 m/s | 5.9 |
| 2024 | 30.5°C | 26.2°C | 22.0°C | 36.5°C | 18.5°C | 258 mm | 85% | 1.9 m/s | 4.8 |
| 2023 | 29.4°C | 24.6°C | 19.8°C | 32.4°C | 12.7°C | 146 mm | 81% | 1.4 m/s | 5.5 |
| 2022 🔥 | 34.3°C | 27.9°C | 21.4°C | 38.4°C | 15.5°C | 73 mm | 69% | 2.3 m/s | 6.8 |
| 2021 | 28.5°C | 24.1°C | 19.7°C | 32.4°C | 14.1°C | 220 mm | 83% | 2.1 m/s | 5.1 |
| 2020 | 31.0°C | 24.9°C | 18.9°C | 35.3°C | 12.0°C | 123 mm | 73% | 1.9 m/s | 6.3 |
| 2019 | 29.9°C | 25.3°C | 20.6°C | 34.5°C | 14.0°C | 170 mm | 81% | 2.2 m/s | 5.4 |
| 2018 | 34.0°C | 27.2°C | 20.5°C | 37.5°C | 15.1°C | 56 mm | 68% | 1.8 m/s | 6.6 |
| 2017 | 30.8°C | 24.5°C | 18.2°C | 33.9°C | 10.8°C | 105 mm | 71% | 2.2 m/s | 6.3 |
| 2016 | 28.1°C | 23.7°C | 19.3°C | 31.7°C | 11.9°C | 273 mm | 84% | 1.8 m/s | 5.3 |
| 2015 🌧️ | 27.9°C | 24.3°C | 20.7°C | 30.6°C | 12.2°C | 327 mm | 87% | 1.9 m/s | 4.9 |
| 2014 | 29.6°C | 23.7°C | 17.7°C | 33.3°C | 10.2°C | 230 mm | 72% | 2.3 m/s | 6 |
| 2013 | 30.0°C | 24.0°C | 18.0°C | 36.0°C | 6.3°C | 80 mm | 71% | 2.3 m/s | 6.1 |
| 2012 | 31.0°C | 25.3°C | 19.7°C | 36.3°C | 15.3°C | 83 mm | 75% | 1.8 m/s | 6.4 |
| 2011 | 33.5°C | 26.7°C | 19.9°C | 38.6°C | 9.3°C | 26 mm | 60% | 2.9 m/s | 6.5 |
| 2010 | 32.7°C | 26.6°C | 20.5°C | 37.3°C | 13.4°C | 80 mm | 70% | 2 m/s | 6.4 |
| 2009 | 30.0°C | 24.6°C | 19.2°C | 34.0°C | 11.5°C | 40 mm | 77% | 1.8 m/s | 6.1 |
| 2008 | 31.3°C | 25.4°C | 19.5°C | 36.5°C | 12.6°C | 83 mm | 71% | 2.3 m/s | 5.8 |
| 2007 | 27.5°C | 23.2°C | 19.0°C | 30.5°C | 13.1°C | 164 mm | 84% | 1.7 m/s | 5.6 |
| 2006 | 31.9°C | 25.6°C | 19.4°C | 35.9°C | 12.9°C | 102 mm | 70% | 2 m/s | 6.1 |
| 2005 | 29.9°C | 23.9°C | 18.0°C | 37.6°C | 8.7°C | 94 mm | 74% | 1.5 m/s | 6.3 |
| 2004 | 28.3°C | 23.6°C | 18.8°C | 35.2°C | 9.8°C | 179 mm | 83% | 2.1 m/s | 5.8 |
| 2003 | 32.6°C | 26.7°C | 20.8°C | 38.1°C | 15.8°C | 9 mm | 73% | 2 m/s | 5.9 |
| 2002 | 32.2°C | 25.9°C | 19.6°C | 35.9°C | 10.7°C | 59 mm | 68% | 2.4 m/s | 6.2 |
| 2001 | 30.1°C | 24.7°C | 19.3°C | 34.5°C | 13.1°C | 95 mm | 77% | 1.9 m/s | 6.2 |
| 2000 | 30.4°C | 25.7°C | 21.0°C | 34.4°C | 14.8°C | 185 mm | 80% | 2.1 m/s | 6 |
| 1999 | 31.0°C | 25.3°C | 19.6°C | 35.1°C | 12.7°C | 139 mm | 75% | 1.8 m/s | 6 |
| 1998 | 35.1°C | 27.6°C | 20.1°C | 40.6°C | 14.6°C | 2 mm | 66% | 2.1 m/s | 6.5 |
| 1997 | 27.5°C | 22.7°C | 17.9°C | 31.6°C | 11.1°C | 157 mm | 85% | 1.6 m/s | 5.6 |
| 1996 | 33.7°C | 27.5°C | 21.4°C | 38.5°C | 12.0°C | 24 mm | 69% | 2.7 m/s | 6.4 |
| 1995 | 29.3°C | 24.3°C | 19.3°C | 32.2°C | 11.4°C | 184 mm | 82% | 2.1 m/s | 5.8 |
| 1994 | 28.4°C | 23.6°C | 18.8°C | 32.6°C | 11.8°C | 160 mm | 82% | 1.5 m/s | 5.7 |
| 1993 ❄️ | 26.8°C | 21.9°C | 17.0°C | 30.7°C | 9.7°C | 193 mm | 84% | 2 m/s | 5.6 |
| 1992 | 26.4°C | 22.0°C | 17.6°C | 29.9°C | 7.8°C | 172 mm | 84% | 1.5 m/s | 5.3 |
| 1991 | 28.3°C | 24.4°C | 20.4°C | 33.0°C | 11.0°C | 155 mm | 87% | 1.8 m/s | 5.1 |
| 1990 | 28.7°C | 24.4°C | 20.1°C | 32.4°C | 12.7°C | 107 mm | 83% | 2.2 m/s | 5.5 |
| 1989 | 30.9°C | 25.6°C | 20.3°C | 34.0°C | 14.7°C | 217 mm | 78% | 2.2 m/s | 5.9 |
| 1988 | 31.1°C | 23.9°C | 16.8°C | 34.2°C | 11.1°C | 27 mm | 66% | 1.9 m/s | 6.2 |
| 1987 | 28.4°C | 24.1°C | 19.8°C | 31.9°C | 16.6°C | 162 mm | 82% | 1.5 m/s | 5.1 |
| 1986 | 28.7°C | 23.5°C | 18.3°C | 32.2°C | 11.9°C | 162 mm | 79% | 2 m/s | 5.5 |
| 1985 | 29.8°C | 24.2°C | 18.5°C | 37.5°C | 12.3°C | 57 mm | 75% | 1.7 m/s | 6.1 |
| 1984 | 30.4°C | 24.4°C | 18.4°C | 36.6°C | 9.9°C | 127 mm | 71% | 2.2 m/s | 5.8 |
| 1983 | 28.3°C | 23.0°C | 17.7°C | 31.4°C | 11.1°C | 213 mm | 79% | 2 m/s | — |
| 1982 | 27.9°C | 23.3°C | 18.7°C | 32.1°C | 9.7°C | 171 mm | 83% | 1.9 m/s | — |
| 1981 | 28.6°C | 23.2°C | 17.7°C | 33.8°C | 8.3°C | 182 mm | 77% | 2 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 30.1°C with lows near 19.3°C (mean 24.7°C), based on 45 years of NASA POWER data.
May averages 134 mm of rainfall in Katy, a relatively wet time of year. The wettest on record was 327 mm in 2015.
The hottest May reached 40.6°C in 1998. The coldest dipped to 6.3°C in 2013.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 2.2°C. Daytime highs moved from 29°C to 30.9°C and overnight lows from 18.2°C to 20.7°C over the same span.
May is one of the warmer months of the year in Katy and a relatively wet time of year, so plan for around 30.1°C daytime highs and 19.3°C at night.
Not quite — May is the 8th coolest month in Katy, averaging 24.7°C.
For May in Katy, pack light, breathable clothing and sun protection, with typical highs of 30.1°C and lows of 19.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 77% — quite humid.
Average wind speed in May is 2 m/s. The windiest May on record averaged 2.9 m/s (2011).
The wettest May on record was 2015 with 327 mm. On average, May sees 134 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 Katy 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.
