June is one of the warmer months of the year in Alton, with average highs near 19.7°C and lows around 10.4°C (mean 15.1°C). It is one of the drier months, averaging 54 mm of rainfall and 78% relative humidity across the period.
June is one of the warmer months of the year in Alton. Across 45 years of records, the warmest June in Alton was 2025 — when the month averaged 17.6°C — while the coldest was 1991 at 12.6°C. Typical June days reach 19.7°C with nights near 10.4°C. The long-term trend is warming, about 0.5°C per decade.
June is one of the drier months in Alton, averaging 54 mm of rainfall. The wettest June on record was 2012 with 145 mm, while the driest was 2018 at 7 mm.
Relative humidity in Alton during June averages 78%. The most humid June was 1998 at 85%, and the least humid was 1989 at 71%.
June receives about 5.3 kWh/m²/day of solar energy in Alton. The sunniest Junes were 2006 and 2018 at 6.1 kWh/m²/day, and the cloudiest was 2012 at 4.2.
Average wind speed in Alton during June is 3.1 m/s. The windiest June was 2012 at 4.2 m/s, while the calmest were 2006 and 2014 at 2.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.4°C | 14.4°C | 15.3°C | 15.2°C | 16.2°C | +1.8°C |
| Avg High | 19.0°C | 19.0°C | 19.8°C | 19.8°C | 21.2°C | +2.2°C |
| Avg Low | 9.9°C | 9.8°C | 10.7°C | 10.6°C | 11.3°C | +1.4°C |
| Avg Rain | 51 mm | 61 mm | 48 mm | 61 mm | 44 mm | -7 mm |
June temperatures in Alton have risen by about 2°C between 1981–1985 and 2021–2025.
June has ranged from a record low of 2.2°C (1991) to a record high of 30.1°C (2017).
Rainfall in June is one of the drier months, averaging 54 mm, with a wettest year of 145 mm.
One of the best times to visit Alton
June is one of the best times to visit Alton. Expect days averaging 19.7°C and nights around 10.4°C (mean 15.1°C) — warmer than Alton's yearly average — with moderate rainfall (54 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 🔥 | 22.6°C | 17.6°C | 12.6°C | 29.8°C | 8.2°C | 41 mm | 75% | 3.4 m/s | 5.9 |
| 2024 | 19.8°C | 14.8°C | 9.9°C | 27.1°C | 6.4°C | 15 mm | 77% | 2.9 m/s | 5.8 |
| 2023 | 22.7°C | 17.3°C | 12.0°C | 26.3°C | 7.5°C | 35 mm | 77% | 3.1 m/s | 6 |
| 2022 | 21.6°C | 16.2°C | 10.9°C | 27.9°C | 6.8°C | 40 mm | 72% | 3.3 m/s | 5.8 |
| 2021 | 20.4°C | 15.8°C | 11.2°C | 25.4°C | 7.4°C | 77 mm | 82% | 2.5 m/s | 5.1 |
| 2020 | 20.1°C | 15.5°C | 10.9°C | 30.1°C | 6.4°C | 57 mm | 75% | 3.5 m/s | 5.2 |
| 2019 | 19.0°C | 14.7°C | 10.5°C | 26.7°C | 7.4°C | 101 mm | 81% | 3.4 m/s | 4.8 |
| 2018 | 22.2°C | 16.8°C | 11.3°C | 27.5°C | 7.8°C | 7 mm | 75% | 2.8 m/s | 6.1 |
| 2017 | 21.9°C | 17.0°C | 12.0°C | 30.1°C | 7.9°C | 53 mm | 75% | 3.5 m/s | 5.5 |
| 2016 | 19.2°C | 15.2°C | 11.2°C | 23.2°C | 8.5°C | 97 mm | 85% | 3 m/s | 4.4 |
| 2015 | 19.8°C | 14.8°C | 9.7°C | 26.6°C | 5.7°C | 31 mm | 75% | 3.6 m/s | 5.7 |
| 2014 | 20.0°C | 15.4°C | 10.8°C | 23.3°C | 7.8°C | 36 mm | 78% | 2.4 m/s | 5.7 |
| 2013 | 18.5°C | 14.0°C | 9.5°C | 24.4°C | 5.8°C | 35 mm | 80% | 3.7 m/s | 5.2 |
| 2012 🌧️ | 17.5°C | 14.0°C | 10.6°C | 22.7°C | 7.3°C | 145 mm | 83% | 4.2 m/s | 4.2 |
| 2011 | 19.2°C | 14.6°C | 10.1°C | 25.7°C | 6.3°C | 71 mm | 77% | 3.7 m/s | 5.2 |
| 2010 | 21.1°C | 15.8°C | 10.5°C | 26.7°C | 5.5°C | 36 mm | 74% | 2.7 m/s | 5.9 |
| 2009 | 20.5°C | 15.6°C | 10.8°C | 26.6°C | 7.0°C | 39 mm | 73% | 2.6 m/s | 5.5 |
| 2008 | 19.0°C | 14.7°C | 10.4°C | 24.5°C | 7.7°C | 41 mm | 79% | 3.2 m/s | 5.5 |
| 2007 | 19.3°C | 15.4°C | 11.5°C | 23.0°C | 6.9°C | 105 mm | 83% | 3.1 m/s | 4.8 |
| 2006 | 21.6°C | 16.3°C | 11.0°C | 27.0°C | 5.6°C | 29 mm | 74% | 2.4 m/s | 6.1 |
| 2005 | 21.3°C | 16.3°C | 11.3°C | 28.1°C | 5.5°C | 40 mm | 76% | 3 m/s | 5.3 |
| 2004 | 19.9°C | 15.5°C | 11.0°C | 25.7°C | 6.8°C | 41 mm | 78% | 3.3 m/s | 5.5 |
| 2003 | 20.4°C | 15.7°C | 11.0°C | 24.6°C | 7.5°C | 80 mm | 80% | 2.9 m/s | 5.3 |
| 2002 | 18.2°C | 14.1°C | 10.0°C | 22.4°C | 7.5°C | 50 mm | 82% | 3.2 m/s | 4.9 |
| 2001 | 18.9°C | 14.3°C | 9.7°C | 26.2°C | 5.1°C | 26 mm | 78% | 2.8 m/s | 5.3 |
| 2000 | 18.9°C | 14.8°C | 10.6°C | 23.6°C | 6.3°C | 34 mm | 83% | 3 m/s | 4.5 |
| 1999 | 18.7°C | 14.2°C | 9.7°C | 23.5°C | 6.3°C | 72 mm | 79% | 2.9 m/s | 5.5 |
| 1998 | 17.7°C | 14.1°C | 10.5°C | 23.0°C | 6.7°C | 104 mm | 85% | 3.9 m/s | 4.5 |
| 1997 | 18.5°C | 14.5°C | 10.5°C | 22.9°C | 7.8°C | 110 mm | 79% | 3.7 m/s | 4.4 |
| 1996 | 19.5°C | 14.4°C | 9.3°C | 25.4°C | 5.8°C | 18 mm | 78% | 2.6 m/s | 6 |
| 1995 | 19.6°C | 14.3°C | 9.0°C | 29.9°C | 5.6°C | 22 mm | 76% | 3.2 m/s | 5.2 |
| 1994 | 19.2°C | 14.3°C | 9.5°C | 23.9°C | 6.2°C | 27 mm | 80% | 3.4 m/s | 5.9 |
| 1993 | 20.1°C | 15.4°C | 10.8°C | 24.9°C | 7.8°C | 61 mm | 81% | 2.5 m/s | 5.5 |
| 1992 | 21.9°C | 16.3°C | 10.7°C | 26.8°C | 6.8°C | 46 mm | 71% | 2.5 m/s | 5.3 |
| 1991 ❄️ | 16.5°C | 12.6°C | 8.6°C | 20.7°C | 2.2°C | 98 mm | 81% | 3.9 m/s | 4.5 |
| 1990 | 18.5°C | 14.1°C | 9.7°C | 23.5°C | 7.5°C | 51 mm | 76% | 3.5 m/s | 4.5 |
| 1989 | 20.7°C | 15.4°C | 10.1°C | 29.0°C | 4.9°C | 38 mm | 71% | 2.8 m/s | 5.4 |
| 1988 | 19.5°C | 14.9°C | 10.2°C | 24.0°C | 5.7°C | 23 mm | 79% | 2.9 m/s | 5.3 |
| 1987 | 17.4°C | 13.2°C | 9.0°C | 25.0°C | 5.8°C | 61 mm | 82% | 3.1 m/s | 4.6 |
| 1986 | 19.8°C | 14.8°C | 9.9°C | 28.1°C | 4.7°C | 28 mm | 79% | 3.4 m/s | 5.3 |
| 1985 | 17.4°C | 13.2°C | 9.0°C | 23.4°C | 3.9°C | 75 mm | 80% | 3.4 m/s | 4.8 |
| 1984 | 20.2°C | 15.1°C | 10.1°C | 25.0°C | 6.2°C | 35 mm | 76% | 2.6 m/s | 5.5 |
| 1983 | 18.6°C | 14.2°C | 9.8°C | 22.9°C | 6.1°C | 60 mm | 82% | 3.1 m/s | — |
| 1982 | 19.7°C | 15.6°C | 11.5°C | 24.6°C | 6.6°C | 88 mm | 81% | 3.1 m/s | — |
| 1981 | 17.3°C | 13.3°C | 9.3°C | 23.0°C | 6.8°C | 53 mm | 82% | 3.6 m/s | — |
Actual recorded June data for each year, 1981–2025 — sourced from NASA POWER.
The average high in June is around 19.7°C with lows near 10.4°C (mean 15.1°C), based on 45 years of NASA POWER data.
June averages 54 mm of rainfall in Alton, one of the drier months. The wettest on record was 145 mm in 2012.
The hottest June reached 30.1°C in 2017. The coldest dipped to 2.2°C in 1991.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average June temperatures have risen by about 2°C. Daytime highs moved from 18.6°C to 21.4°C and overnight lows from 9.9°C to 11.3°C over the same span.
June is one of the warmer months of the year in Alton and one of the drier months, so plan for around 19.7°C daytime highs and 10.4°C at night.
Not quite — June is the 9th coolest month in Alton, averaging 15.1°C.
For June in Alton, pack light layers you can adjust through the day, with typical highs of 19.7°C and lows of 10.4°C. Bring an umbrella or light rain jacket too.
Relative humidity in June averages 78% — quite humid.
Average wind speed in June is 3.1 m/s. The windiest June on record averaged 4.2 m/s (2012).
The wettest June on record was 2012 with 145 mm. On average, June sees 54 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 Alton behaves each June, 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 June specifically, along with year-by-year records and how the month has changed over the decades.
