August is one of the cooler months of the year in Somerville, with average highs near 13.5°C and lows around 6.7°C (mean 10.1°C). It is about average for rainfall, averaging 70 mm of rainfall and 82% relative humidity across the period.
August is one of the cooler months of the year in Somerville. Across 45 years of records, the warmest August in Somerville was 2024 — when the month averaged 12.2°C — while the coldest were 1989 and 1992 at 8.8°C. Typical August days reach 13.5°C with nights near 6.7°C. The long-term trend is warming, about 0.2°C per decade.
August is about average for rainfall in Somerville, averaging 70 mm of rainfall. The wettest August on record was 1981 with 119 mm, while the driest was 1982 at 27 mm.
Relative humidity in Somerville during August averages 82%. The most humid August was 1989 at 87%, and the least humid was 2018 at 75%.
August receives about 2.8 kWh/m²/day of solar energy in Somerville. The sunniest Augusts were 1998, 2014 and 2025, among others at 3.1 kWh/m²/day, and the cloudiest was 2013 at 2.5.
Average wind speed in Somerville during August is 3.6 m/s. The windiest August was 1991 at 5 m/s, while the calmest was 2014 at 2.5 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.8°C | 9.8°C | 10.3°C | 10.0°C | 10.9°C | +1.1°C |
| Avg High | 13.1°C | 13.1°C | 13.8°C | 13.3°C | 14.4°C | +1.3°C |
| Avg Low | 6.4°C | 6.4°C | 6.8°C | 6.8°C | 7.4°C | +1°C |
| Avg Rain | 76 mm | 76 mm | 69 mm | 69 mm | 58 mm | -18 mm |
August temperatures in Somerville have risen by about 1.2°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 1°C (2003) to a record high of 21.3°C (1982).
Rainfall in August is about average for rainfall, averaging 70 mm, with a wettest year of 119 mm.
A quieter season to visit Somerville
If your dates are flexible, the more temperate months of February and January tend to be the most comfortable for visiting Somerville. That said, August — with days averaging 13.5°C and nights around 6.7°C (mean 10.1°C) and moderate rainfall (70 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 14.5°C | 10.7°C | 6.9°C | 19.0°C | 3.9°C | 52 mm | 80% | 3 m/s | 3.1 |
| 2024 🔥 | 16.0°C | 12.2°C | 8.4°C | 20.1°C | 4.0°C | 30 mm | 78% | 3.5 m/s | 3 |
| 2023 | 14.9°C | 11.3°C | 7.7°C | 19.8°C | 3.3°C | 34 mm | 81% | 3 m/s | 2.8 |
| 2022 | 13.8°C | 10.7°C | 7.7°C | 17.3°C | 3.7°C | 116 mm | 84% | 3.5 m/s | 2.6 |
| 2021 | 14.0°C | 10.6°C | 7.2°C | 18.1°C | 4.5°C | 41 mm | 83% | 3.6 m/s | 3 |
| 2020 | 12.9°C | 9.7°C | 6.6°C | 16.7°C | 3.7°C | 73 mm | 85% | 3.8 m/s | 2.9 |
| 2019 | 13.0°C | 9.7°C | 6.4°C | 16.4°C | 4.0°C | 75 mm | 81% | 3.8 m/s | 2.7 |
| 2018 | 13.3°C | 9.9°C | 6.4°C | 16.5°C | 3.8°C | 57 mm | 75% | 4.2 m/s | 2.9 |
| 2017 | 13.2°C | 10.0°C | 6.8°C | 18.5°C | 4.4°C | 73 mm | 80% | 3.8 m/s | 2.8 |
| 2016 | 13.8°C | 10.3°C | 6.9°C | 17.7°C | 4.4°C | 75 mm | 82% | 3.4 m/s | 2.9 |
| 2015 | 12.5°C | 9.5°C | 6.4°C | 16.5°C | 3.9°C | 53 mm | 81% | 3.3 m/s | 2.7 |
| 2014 | 13.8°C | 10.3°C | 6.7°C | 18.3°C | 2.5°C | 38 mm | 83% | 2.5 m/s | 3.1 |
| 2013 | 13.6°C | 10.6°C | 7.6°C | 18.9°C | 3.7°C | 98 mm | 84% | 4.6 m/s | 2.5 |
| 2012 | 12.7°C | 9.7°C | 6.6°C | 16.0°C | 3.9°C | 78 mm | 84% | 4.2 m/s | 2.8 |
| 2011 | 14.9°C | 11.1°C | 7.4°C | 18.6°C | 4.8°C | 36 mm | 83% | 2.6 m/s | 2.8 |
| 2010 | 12.2°C | 9.3°C | 6.5°C | 15.1°C | 4.2°C | 113 mm | 85% | 4 m/s | 2.7 |
| 2009 | 14.7°C | 11.0°C | 7.3°C | 17.7°C | 3.6°C | 63 mm | 78% | 4.7 m/s | 2.7 |
| 2008 | 12.3°C | 9.2°C | 6.1°C | 16.2°C | 4.0°C | 82 mm | 84% | 3.4 m/s | 2.7 |
| 2007 | 14.4°C | 10.8°C | 7.2°C | 20.3°C | 3.6°C | 45 mm | 82% | 3.6 m/s | 2.9 |
| 2006 | 14.5°C | 10.7°C | 6.8°C | 19.4°C | 4.4°C | 32 mm | 78% | 2.8 m/s | 3 |
| 2005 | 14.3°C | 10.8°C | 7.4°C | 18.5°C | 4.3°C | 90 mm | 78% | 4.4 m/s | 2.8 |
| 2004 | 13.8°C | 10.3°C | 6.8°C | 18.8°C | 3.2°C | 84 mm | 82% | 3.4 m/s | 2.8 |
| 2003 | 12.7°C | 9.4°C | 6.1°C | 15.3°C | 1.0°C | 90 mm | 81% | 4.1 m/s | 2.8 |
| 2002 | 14.1°C | 10.5°C | 6.9°C | 17.1°C | 3.8°C | 43 mm | 78% | 3.2 m/s | 2.8 |
| 2001 | 13.8°C | 10.5°C | 7.1°C | 17.1°C | 4.1°C | 99 mm | 80% | 4.3 m/s | 2.6 |
| 2000 | 13.7°C | 10.2°C | 6.6°C | 17.6°C | 4.3°C | 60 mm | 84% | 2.8 m/s | 2.9 |
| 1999 | 14.1°C | 10.9°C | 7.7°C | 19.8°C | 4.6°C | 91 mm | 85% | 3.2 m/s | 2.6 |
| 1998 | 14.0°C | 10.4°C | 6.8°C | 18.2°C | 3.9°C | 29 mm | 85% | 2.6 m/s | 3.1 |
| 1997 | 13.1°C | 9.7°C | 6.2°C | 16.9°C | 2.0°C | 67 mm | 80% | 3.7 m/s | 2.7 |
| 1996 | 12.6°C | 9.5°C | 6.5°C | 15.3°C | 4.2°C | 81 mm | 86% | 4 m/s | 2.6 |
| 1995 | 13.7°C | 10.0°C | 6.2°C | 18.4°C | 3.1°C | 57 mm | 84% | 3.7 m/s | 3.1 |
| 1994 | 12.7°C | 9.3°C | 5.8°C | 19.3°C | 3.7°C | 44 mm | 80% | 3.5 m/s | 2.9 |
| 1993 | 14.6°C | 10.7°C | 6.8°C | 18.2°C | 3.4°C | 94 mm | 82% | 3.8 m/s | 2.9 |
| 1992 | 12.1°C | 8.8°C | 5.4°C | 15.5°C | 2.7°C | 95 mm | 84% | 4 m/s | 2.7 |
| 1991 | 12.4°C | 9.2°C | 6.0°C | 15.6°C | 3.7°C | 107 mm | 84% | 5 m/s | 2.7 |
| 1990 | 11.9°C | 9.2°C | 6.6°C | 15.4°C | 3.9°C | 93 mm | 85% | 4.1 m/s | 2.8 |
| 1989 ❄️ | 11.9°C | 8.8°C | 5.8°C | 15.1°C | 3.2°C | 93 mm | 87% | 3.3 m/s | 2.8 |
| 1988 | 13.7°C | 10.4°C | 7.0°C | 18.2°C | 4.1°C | 66 mm | 84% | 3.6 m/s | 2.9 |
| 1987 | 13.1°C | 9.8°C | 6.5°C | 16.1°C | 4.1°C | 49 mm | 85% | 2.9 m/s | 2.9 |
| 1986 | 12.9°C | 9.3°C | 5.7°C | 16.2°C | 2.5°C | 56 mm | 86% | 3.1 m/s | 3.1 |
| 1985 | 12.6°C | 9.3°C | 6.0°C | 15.8°C | 2.2°C | 97 mm | 85% | 3.5 m/s | 2.9 |
| 1984 | 12.9°C | 9.9°C | 6.9°C | 15.4°C | 4.1°C | 96 mm | 85% | 4.2 m/s | 2.8 |
| 1983 | 13.4°C | 10.1°C | 6.9°C | 16.7°C | 2.7°C | 77 mm | 85% | 3.2 m/s | — |
| 1982 | 15.5°C | 10.9°C | 6.4°C | 21.3°C | 2.9°C | 27 mm | 78% | 2.6 m/s | — |
| 1981 🌧️ | 12.3°C | 9.3°C | 6.2°C | 14.7°C | 3.7°C | 119 mm | 86% | 4.2 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 13.5°C with lows near 6.7°C (mean 10.1°C), based on 45 years of NASA POWER data.
August averages 70 mm of rainfall in Somerville, about average for rainfall. The wettest on record was 119 mm in 1981.
The hottest August reached 21.3°C in 1982. The coldest dipped to 1°C in 2003.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 1.2°C. Daytime highs moved from 13.3°C to 14.6°C and overnight lows from 6.5°C to 7.6°C over the same span.
August is one of the cooler months of the year in Somerville and about average for rainfall, so plan for around 13.5°C daytime highs and 6.7°C at night.
Not quite — August is the 2nd coolest month in Somerville, averaging 10.1°C.
For August in Somerville, pack warm layers and a jacket for chilly mornings, with typical highs of 13.5°C and lows of 6.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 82% — quite humid.
Average wind speed in August is 3.6 m/s. The windiest August on record averaged 5 m/s (1991).
The wettest August on record was 1981 with 119 mm. On average, August sees 70 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 Somerville behaves each August, 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 August specifically, along with year-by-year records and how the month has changed over the decades.
