May is one of the warmer months of the year in Round Rock, with average highs near 30.7°C and lows around 18.5°C (mean 24.6°C). It is a relatively wet time of year, averaging 118 mm of rainfall and 71% relative humidity across the period.
May is one of the warmer months of the year in Round Rock. Across 45 years of records, the warmest May in Round Rock was 2022 — when the month averaged 28.3°C — while the coldest was 1992 at 21.2°C. Typical May days reach 30.7°C with nights near 18.5°C. The long-term trend is warming, about 0.3°C per decade.
May is a relatively wet time of year in Round Rock, averaging 118 mm of rainfall. The wettest May on record was 2015 with 318 mm, while the driest was 1998 at 16 mm.
Relative humidity in Round Rock during May averages 71%. The most humid May was 2015 at 85%, and the least humid was 1984 at 54%.
May receives about 5.8 kWh/m²/day of solar energy in Round Rock. The sunniest May was 2022 at 6.7 kWh/m²/day, and the cloudiest was 2015 at 4.6.
Average wind speed in Round Rock during May is 3 m/s. The windiest May was 1996 at 4.3 m/s, while the calmest was 2023 at 1.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 24.1°C | 24.4°C | 25.0°C | 24.5°C | 25.6°C | +1.5°C |
| Avg High | 30.3°C | 30.4°C | 31.1°C | 30.5°C | 31.5°C | +1.2°C |
| Avg Low | 17.7°C | 18.3°C | 18.8°C | 18.5°C | 19.6°C | +1.9°C |
| Avg Rain | 126 mm | 120 mm | 84 mm | 133 mm | 134 mm | +8 mm |
May temperatures in Round Rock have risen by about 1.8°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 6.3°C (2013) to a record high of 41.7°C (1984).
Rainfall in May is a relatively wet time of year, averaging 118 mm, with a wettest year of 318 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.2°C per decade while lows rose 0.4°C per decade, narrowing the gap between day and night.
One of the best times to visit Round Rock
May is one of the best times to visit Round Rock. Expect days averaging 30.7°C and nights around 18.5°C (mean 24.6°C) — warmer than Round Rock's yearly average — with higher rainfall (118 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 | 32.8°C | 26.3°C | 19.7°C | 39.3°C | 13.5°C | 143 mm | 68% | 2.9 m/s | 6.2 |
| 2024 | 32.6°C | 27.0°C | 21.4°C | 38.5°C | 17.1°C | 157 mm | 77% | 2.7 m/s | 4.9 |
| 2023 | 29.4°C | 24.1°C | 18.8°C | 33.9°C | 12.2°C | 111 mm | 77% | 1.9 m/s | 5.5 |
| 2022 🔥 | 35.6°C | 28.3°C | 21.1°C | 39.4°C | 13.8°C | 57 mm | 61% | 3.6 m/s | 6.7 |
| 2021 | 28.5°C | 23.5°C | 18.6°C | 33.6°C | 12.4°C | 191 mm | 81% | 3 m/s | 4.9 |
| 2020 | 30.2°C | 24.1°C | 18.0°C | 35.9°C | 11.8°C | 142 mm | 71% | 2.9 m/s | 6.5 |
| 2019 | 28.8°C | 24.0°C | 19.1°C | 33.5°C | 11.5°C | 158 mm | 81% | 3.1 m/s | 5.2 |
| 2018 | 33.5°C | 26.7°C | 19.9°C | 39.2°C | 14.2°C | 90 mm | 66% | 2.7 m/s | 6.5 |
| 2017 | 31.1°C | 24.2°C | 17.3°C | 35.4°C | 10.6°C | 74 mm | 66% | 3.2 m/s | 5.7 |
| 2016 | 27.8°C | 22.9°C | 18.0°C | 31.2°C | 10.3°C | 202 mm | 81% | 2.7 m/s | 5.1 |
| 2015 🌧️ | 27.7°C | 23.6°C | 19.5°C | 30.2°C | 11.7°C | 318 mm | 85% | 3 m/s | 4.6 |
| 2014 | 30.2°C | 23.7°C | 17.2°C | 35.1°C | 8.4°C | 176 mm | 66% | 3.4 m/s | 6.1 |
| 2013 | 30.1°C | 23.8°C | 17.4°C | 36.0°C | 6.3°C | 102 mm | 67% | 3.5 m/s | 5.8 |
| 2012 | 31.5°C | 25.4°C | 19.3°C | 36.8°C | 13.7°C | 105 mm | 71% | 2.8 m/s | 6.3 |
| 2011 | 32.8°C | 25.6°C | 18.3°C | 39.6°C | 7.1°C | 56 mm | 60% | 3.9 m/s | 6.3 |
| 2010 | 31.3°C | 25.3°C | 19.4°C | 36.1°C | 12.0°C | 49 mm | 69% | 2.9 m/s | 5.9 |
| 2009 | 31.0°C | 24.8°C | 18.7°C | 35.8°C | 10.5°C | 51 mm | 69% | 2.6 m/s | 6.1 |
| 2008 | 31.9°C | 25.3°C | 18.8°C | 37.7°C | 11.4°C | 82 mm | 66% | 3.2 m/s | 6.2 |
| 2007 | 27.3°C | 22.9°C | 18.4°C | 31.1°C | 12.6°C | 182 mm | 81% | 2.5 m/s | 5.2 |
| 2006 | 31.2°C | 24.9°C | 18.6°C | 36.0°C | 12.0°C | 92 mm | 68% | 3 m/s | 6.5 |
| 2005 | 29.3°C | 23.4°C | 17.5°C | 37.2°C | 7.5°C | 106 mm | 72% | 2.5 m/s | 5.8 |
| 2004 | 30.5°C | 24.5°C | 18.5°C | 40.3°C | 8.6°C | 49 mm | 73% | 3.5 m/s | 5.6 |
| 2003 | 33.9°C | 27.1°C | 20.2°C | 39.0°C | 15.6°C | 32 mm | 65% | 3.1 m/s | 5.5 |
| 2002 | 33.5°C | 26.3°C | 19.1°C | 39.2°C | 10.9°C | 47 mm | 59% | 3.8 m/s | 6.2 |
| 2001 | 30.1°C | 24.3°C | 18.5°C | 35.4°C | 11.2°C | 104 mm | 74% | 3 m/s | 6.3 |
| 2000 | 32.0°C | 26.0°C | 20.0°C | 38.4°C | 12.5°C | 91 mm | 72% | 3.4 m/s | 6 |
| 1999 | 31.1°C | 24.9°C | 18.6°C | 36.0°C | 12.1°C | 126 mm | 70% | 2.7 m/s | 5.8 |
| 1998 | 36.2°C | 27.8°C | 19.5°C | 41.1°C | 13.5°C | 16 mm | 56% | 3.2 m/s | 6.5 |
| 1997 | 27.5°C | 22.2°C | 16.8°C | 32.0°C | 10.0°C | 126 mm | 80% | 2.5 m/s | 5.5 |
| 1996 | 34.9°C | 28.0°C | 21.0°C | 39.6°C | 10.4°C | 56 mm | 62% | 4.3 m/s | 5.9 |
| 1995 | 31.1°C | 24.8°C | 18.5°C | 37.1°C | 10.4°C | 185 mm | 71% | 3.1 m/s | 5.4 |
| 1994 | 29.3°C | 23.7°C | 18.1°C | 34.4°C | 9.3°C | 139 mm | 77% | 2.2 m/s | 5.5 |
| 1993 | 27.7°C | 22.0°C | 16.2°C | 31.8°C | 8.8°C | 120 mm | 77% | 3 m/s | 5.9 |
| 1992 ❄️ | 25.9°C | 21.2°C | 16.4°C | 31.8°C | 7.5°C | 216 mm | 84% | 2.5 m/s | 5.5 |
| 1991 | 29.1°C | 24.2°C | 19.3°C | 34.7°C | 8.7°C | 116 mm | 81% | 2.7 m/s | 5.1 |
| 1990 | 30.9°C | 24.8°C | 18.7°C | 36.4°C | 11.6°C | 99 mm | 72% | 3.5 m/s | 5.9 |
| 1989 | 31.7°C | 25.4°C | 19.1°C | 37.1°C | 14.5°C | 150 mm | 71% | 3.3 m/s | 5.8 |
| 1988 | 31.3°C | 23.8°C | 16.2°C | 36.9°C | 11.2°C | 94 mm | 62% | 2.8 m/s | 6.1 |
| 1987 | 29.0°C | 24.1°C | 19.1°C | 33.9°C | 15.1°C | 183 mm | 78% | 2.4 m/s | 5 |
| 1986 | 28.5°C | 23.1°C | 17.7°C | 32.3°C | 11.7°C | 156 mm | 76% | 2.9 m/s | 4.7 |
| 1985 | 30.4°C | 24.1°C | 17.7°C | 39.3°C | 13.0°C | 70 mm | 70% | 2.7 m/s | 6.3 |
| 1984 | 33.7°C | 26.0°C | 18.3°C | 41.7°C | 11.5°C | 43 mm | 54% | 3.6 m/s | 6 |
| 1983 | 29.5°C | 23.0°C | 16.4°C | 36.9°C | 10.2°C | 164 mm | 72% | 3 m/s | — |
| 1982 | 28.9°C | 23.3°C | 17.7°C | 34.6°C | 9.3°C | 149 mm | 77% | 3 m/s | — |
| 1981 | 30.1°C | 23.8°C | 17.4°C | 36.3°C | 10.0°C | 126 mm | 69% | 3.2 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 30.7°C with lows near 18.5°C (mean 24.6°C), based on 45 years of NASA POWER data.
May averages 118 mm of rainfall in Round Rock, a relatively wet time of year. The wettest on record was 318 mm in 2015.
The hottest May reached 41.7°C in 1984. 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 1.8°C. Daytime highs moved from 30.5°C to 31.8°C and overnight lows from 17.5°C to 19.9°C over the same span.
May is one of the warmer months of the year in Round Rock and a relatively wet time of year, so plan for around 30.7°C daytime highs and 18.5°C at night.
Not quite — May is the 8th coolest month in Round Rock, averaging 24.6°C.
For May in Round Rock, pack light, breathable clothing and sun protection, with typical highs of 30.7°C and lows of 18.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 71% — moderately humid.
Average wind speed in May is 3 m/s. The windiest May on record averaged 4.3 m/s (1996).
The wettest May on record was 2015 with 318 mm. On average, May sees 118 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 Round Rock 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.
