May is one of the cooler months of the year in Horsham, with average highs near 17.8°C and lows around 7°C (mean 12.4°C). It is about average for rainfall, averaging 41 mm of rainfall and 75% relative humidity across the period.
May is one of the cooler months of the year in Horsham. Across 45 years of records, the warmest May in Horsham was 1988 — when the month averaged 14°C — while the coldest was 2006 at 10.7°C. Typical May days reach 17.8°C with nights near 7°C. The long-term May temperature trend is broadly flat.
May is about average for rainfall in Horsham, averaging 41 mm of rainfall. The wettest May on record was 1988 with 105 mm, while the driest was 1991 at 4 mm.
Relative humidity in Horsham during May averages 75%. The most humid May was 1983 at 81%, and the least humid was 2005 at 66%.
May receives about 2.7 kWh/m²/day of solar energy in Horsham. The sunniest May was 2025 at 3.2 kWh/m²/day, and the cloudiest was 1988 at 2.3.
Average wind speed in Horsham during May is 2.7 m/s. The windiest Mays were 1994 and 2016 at 3.6 m/s, while the calmest was 2024 at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 12.5°C | 12.3°C | 12.5°C | 12.5°C | 12.1°C | -0.4°C |
| Avg High | 17.8°C | 17.7°C | 18.0°C | 17.8°C | 17.7°C | -0.1°C |
| Avg Low | 7.1°C | 6.8°C | 7.0°C | 7.2°C | 6.5°C | -0.6°C |
| Avg Rain | 59 mm | 35 mm | 33 mm | 45 mm | 33 mm | -25 mm |
May temperatures in Horsham have stayed relatively stable across the record.
May has ranged from a record low of 0.1°C (2021) to a record high of 27.5°C (2002).
Rainfall in May is about average for rainfall, averaging 41 mm, with a wettest year of 105 mm.
A good time to visit Horsham
May is a good time to visit Horsham, with days averaging 17.8°C and nights around 7°C (mean 12.4°C, cooler than Horsham's yearly average) and moderate rainfall. February and January 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 | 19.5°C | 13.2°C | 6.8°C | 25.2°C | 2.1°C | 11 mm | 66% | 2.6 m/s | 3.2 |
| 2024 | 18.9°C | 12.8°C | 6.7°C | 21.6°C | 2.9°C | 23 mm | 73% | 2.1 m/s | 3 |
| 2023 | 16.7°C | 11.5°C | 6.2°C | 22.0°C | 2.9°C | 40 mm | 78% | 2.7 m/s | 2.6 |
| 2022 | 17.1°C | 12.1°C | 7.1°C | 21.6°C | 4.1°C | 35 mm | 80% | 2.7 m/s | 2.5 |
| 2021 | 17.6°C | 12.0°C | 6.4°C | 25.6°C | 0.1°C | 48 mm | 74% | 2.9 m/s | 2.7 |
| 2020 | 16.2°C | 10.9°C | 5.6°C | 21.9°C | 1.9°C | 41 mm | 78% | 3.1 m/s | 2.7 |
| 2019 | 18.1°C | 12.6°C | 7.2°C | 24.3°C | 3.5°C | 76 mm | 75% | 3.2 m/s | 2.7 |
| 2018 | 17.7°C | 12.5°C | 7.4°C | 23.8°C | 3.2°C | 61 mm | 75% | 3.2 m/s | 2.5 |
| 2017 | 17.3°C | 11.9°C | 6.5°C | 21.5°C | 2.0°C | 54 mm | 76% | 2.5 m/s | 2.7 |
| 2016 | 18.4°C | 13.5°C | 8.5°C | 26.6°C | 2.1°C | 50 mm | 73% | 3.6 m/s | 2.5 |
| 2015 | 17.5°C | 12.2°C | 7.0°C | 23.5°C | 2.9°C | 39 mm | 76% | 3.5 m/s | 2.8 |
| 2014 | 18.9°C | 13.7°C | 8.6°C | 24.1°C | 3.0°C | 41 mm | 78% | 2.7 m/s | 2.4 |
| 2013 | 18.0°C | 12.6°C | 7.2°C | 25.9°C | 3.6°C | 38 mm | 73% | 2.8 m/s | 2.6 |
| 2012 | 17.9°C | 12.2°C | 6.5°C | 24.4°C | 2.7°C | 30 mm | 74% | 2.8 m/s | 2.8 |
| 2011 | 16.0°C | 10.9°C | 5.8°C | 23.0°C | 2.3°C | 30 mm | 78% | 2.5 m/s | 2.6 |
| 2010 | 17.8°C | 12.6°C | 7.4°C | 23.4°C | 1.8°C | 32 mm | 77% | 2.4 m/s | 2.7 |
| 2009 | 18.1°C | 12.8°C | 7.4°C | 21.0°C | 5.3°C | 38 mm | 80% | 2.6 m/s | 2.7 |
| 2008 | 17.8°C | 12.2°C | 6.5°C | 21.9°C | 2.3°C | 40 mm | 76% | 2.2 m/s | 2.6 |
| 2007 | 19.0°C | 13.9°C | 8.9°C | 24.0°C | 4.3°C | 80 mm | 76% | 3.4 m/s | 2.6 |
| 2006 ❄️ | 16.2°C | 10.7°C | 5.2°C | 20.2°C | 1.9°C | 25 mm | 79% | 2.5 m/s | 2.6 |
| 2005 | 19.2°C | 13.1°C | 7.0°C | 26.0°C | 2.6°C | 8 mm | 66% | 2.4 m/s | 3 |
| 2004 | 17.3°C | 11.5°C | 5.7°C | 21.9°C | 2.7°C | 22 mm | 75% | 2.9 m/s | 2.8 |
| 2003 | 18.7°C | 13.1°C | 7.4°C | 24.1°C | 2.6°C | 39 mm | 72% | 2.4 m/s | 2.7 |
| 2002 | 18.8°C | 13.2°C | 7.6°C | 27.5°C | 4.7°C | 31 mm | 69% | 2.5 m/s | 2.8 |
| 2001 | 17.8°C | 12.5°C | 7.2°C | 25.9°C | 4.5°C | 13 mm | 74% | 2.2 m/s | 2.7 |
| 2000 | 16.9°C | 11.8°C | 6.7°C | 21.8°C | 3.0°C | 35 mm | 77% | 3.1 m/s | 2.7 |
| 1999 | 18.7°C | 12.9°C | 7.2°C | 24.9°C | 1.4°C | 56 mm | 69% | 3 m/s | 2.7 |
| 1998 | 17.6°C | 12.1°C | 6.6°C | 23.3°C | 3.0°C | 17 mm | 78% | 2.5 m/s | 2.7 |
| 1997 | 17.2°C | 12.1°C | 7.0°C | 24.6°C | 2.0°C | 56 mm | 77% | 2.4 m/s | 2.5 |
| 1996 | 18.2°C | 12.4°C | 6.6°C | 24.6°C | 3.1°C | 14 mm | 76% | 2.3 m/s | 2.6 |
| 1995 | 16.4°C | 11.6°C | 6.7°C | 22.9°C | 3.6°C | 47 mm | 80% | 2.7 m/s | 2.6 |
| 1994 | 17.7°C | 12.4°C | 7.0°C | 24.3°C | 2.6°C | 31 mm | 69% | 3.6 m/s | 2.7 |
| 1993 | 18.3°C | 12.7°C | 7.1°C | 26.3°C | 2.8°C | 28 mm | 72% | 2.4 m/s | 2.7 |
| 1992 | 16.2°C | 11.3°C | 6.4°C | 24.6°C | 2.3°C | 85 mm | 80% | 2.3 m/s | 2.5 |
| 1991 | 18.3°C | 12.4°C | 6.6°C | 21.5°C | 2.9°C | 4 mm | 74% | 2.3 m/s | 2.8 |
| 1990 | 18.3°C | 12.7°C | 7.1°C | 26.4°C | 1.9°C | 11 mm | 71% | 2.9 m/s | 2.8 |
| 1989 | 17.9°C | 13.0°C | 8.1°C | 22.6°C | 2.9°C | 74 mm | 80% | 2.9 m/s | 2.5 |
| 1988 🔥 🌧️ | 19.0°C | 14.0°C | 9.0°C | 26.8°C | 4.3°C | 105 mm | 79% | 2.5 m/s | 2.3 |
| 1987 | 16.7°C | 11.8°C | 7.0°C | 23.0°C | 3.2°C | 83 mm | 79% | 3.3 m/s | 2.5 |
| 1986 | 17.5°C | 12.3°C | 7.0°C | 22.6°C | 4.2°C | 62 mm | 79% | 2.6 m/s | 2.6 |
| 1985 | 18.3°C | 12.8°C | 7.3°C | 27.3°C | 1.7°C | 31 mm | 70% | 2.9 m/s | 2.8 |
| 1984 | 18.3°C | 12.2°C | 6.2°C | 24.5°C | 3.4°C | 21 mm | 72% | 2.4 m/s | 2.8 |
| 1983 | 17.4°C | 12.3°C | 7.2°C | 21.4°C | 2.5°C | 66 mm | 81% | 3 m/s | — |
| 1982 | 17.2°C | 11.6°C | 6.0°C | 22.8°C | 1.8°C | 24 mm | 71% | 2.9 m/s | — |
| 1981 | 17.8°C | 12.2°C | 6.5°C | 26.5°C | 2.3°C | 62 mm | 71% | 3 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 17.8°C with lows near 7°C (mean 12.4°C), based on 45 years of NASA POWER data.
May averages 41 mm of rainfall in Horsham, about average for rainfall. The wettest on record was 105 mm in 1988.
The hottest May reached 27.5°C in 2002. The coldest dipped to 0.1°C in 2021.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 0.1°C. Daytime highs moved from 17.8°C to 18°C and overnight lows from 6.6°C to 6.6°C over the same span.
May is one of the cooler months of the year in Horsham and about average for rainfall, so plan for around 17.8°C daytime highs and 7°C at night.
Not quite — May is the 5th coolest month in Horsham, averaging 12.4°C.
For May in Horsham, pack warm layers and a jacket for chilly mornings, with typical highs of 17.8°C and lows of 7°C.
Relative humidity in May averages 75% — quite humid.
Average wind speed in May is 2.7 m/s. The windiest May on record averaged 3.6 m/s (1994).
The wettest May on record was 1988 with 105 mm. On average, May sees 41 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 Horsham 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.
