July is one of the warmer months of the year in Dumbarton, with average highs near 17.1°C and lows around 10.2°C (mean 13.7°C). It is about average for rainfall, averaging 109 mm of rainfall and 85% relative humidity across the period.
July is one of the warmer months of the year in Dumbarton. Across 45 years of records, the warmest Julys in Dumbarton were 2006 and 2021 — when the month averaged 15.8°C — while the coldest was 1993 at 11.7°C. Typical July days reach 17.1°C with nights near 10.2°C. The long-term July temperature trend is broadly flat.
July is about average for rainfall in Dumbarton, averaging 109 mm of rainfall. The wettest July on record was 1985 with 190 mm, while the driest was 1983 at 33 mm.
Relative humidity in Dumbarton during July averages 85%. The most humid July was 2016 at 88%, and the least humid was 1984 at 81%.
July receives about 4.5 kWh/m²/day of solar energy in Dumbarton. The sunniest July was 1989 at 5.5 kWh/m²/day, and the cloudiest was 1985 at 3.8.
Average wind speed in Dumbarton during July is 3 m/s. The windiest Julys were 1993 and 2010 at 3.8 m/s, while the calmest was 2021 at 1.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 13.5°C | 13.5°C | 13.7°C | 13.7°C | 14.0°C | +0.5°C |
| Avg High | 17.1°C | 16.9°C | 17.1°C | 17.1°C | 17.5°C | +0.4°C |
| Avg Low | 9.9°C | 10.0°C | 10.3°C | 10.3°C | 10.5°C | +0.6°C |
| Avg Rain | 93 mm | 109 mm | 105 mm | 130 mm | 107 mm | +14 mm |
July temperatures in Dumbarton have risen by about 0.6°C between 1981–1985 and 2021–2025.
July has ranged from a record low of 4.6°C (1993) to a record high of 25.7°C (2025).
Rainfall in July is about average for rainfall, averaging 109 mm, with a wettest year of 190 mm.
One of the best times to visit Dumbarton
July is one of the best times to visit Dumbarton. Expect days averaging 17.1°C and nights around 10.2°C (mean 13.7°C) — warmer than Dumbarton's yearly average — with higher rainfall (109 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 | 18.6°C | 14.9°C | 11.2°C | 25.7°C | 6.7°C | 86 mm | 86% | 2.9 m/s | 4.4 |
| 2024 | 16.6°C | 13.2°C | 9.8°C | 19.8°C | 6.5°C | 104 mm | 85% | 2.9 m/s | 4.5 |
| 2023 | 16.8°C | 13.6°C | 10.4°C | 22.9°C | 6.8°C | 159 mm | 85% | 3.5 m/s | 4.4 |
| 2022 | 18.0°C | 14.3°C | 10.7°C | 24.7°C | 7.9°C | 82 mm | 85% | 3.2 m/s | 4.6 |
| 2021 | 19.6°C | 15.8°C | 12.0°C | 24.0°C | 9.8°C | 69 mm | 85% | 1.9 m/s | 5.2 |
| 2020 | 15.4°C | 12.2°C | 9.1°C | 23.3°C | 6.5°C | 143 mm | 86% | 3.4 m/s | 4.1 |
| 2019 | 18.3°C | 15.0°C | 11.6°C | 25.4°C | 7.1°C | 135 mm | 86% | 3 m/s | 4.2 |
| 2018 | 19.0°C | 15.2°C | 11.3°C | 22.3°C | 9.2°C | 106 mm | 82% | 2.5 m/s | 5.1 |
| 2017 | 16.0°C | 12.9°C | 9.7°C | 21.9°C | 7.0°C | 133 mm | 86% | 3.4 m/s | 4.5 |
| 2016 | 16.1°C | 12.9°C | 9.6°C | 24.1°C | 6.7°C | 138 mm | 88% | 3.3 m/s | 4.1 |
| 2015 | 15.6°C | 12.1°C | 8.6°C | 24.7°C | 5.2°C | 167 mm | 86% | 3.3 m/s | 4.3 |
| 2014 | 18.2°C | 14.5°C | 10.8°C | 23.8°C | 8.2°C | 101 mm | 84% | 2.7 m/s | 5 |
| 2013 | 19.0°C | 15.2°C | 11.4°C | 23.3°C | 7.8°C | 88 mm | 86% | 2.7 m/s | 5.3 |
| 2012 | 15.4°C | 12.4°C | 9.4°C | 20.5°C | 6.9°C | 142 mm | 87% | 2.7 m/s | 4.1 |
| 2011 | 17.0°C | 13.3°C | 9.6°C | 20.1°C | 5.8°C | 110 mm | 83% | 2.1 m/s | 5.2 |
| 2010 | 16.5°C | 13.5°C | 10.5°C | 18.9°C | 8.2°C | 179 mm | 87% | 3.8 m/s | 4 |
| 2009 | 17.1°C | 13.8°C | 10.5°C | 24.8°C | 6.9°C | 149 mm | 85% | 3.1 m/s | 4.8 |
| 2008 | 17.4°C | 14.1°C | 10.7°C | 22.7°C | 6.0°C | 124 mm | 86% | 3.5 m/s | 4.2 |
| 2007 | 15.9°C | 12.7°C | 9.6°C | 18.0°C | 6.4°C | 123 mm | 87% | 3 m/s | 4.7 |
| 2006 🔥 | 19.7°C | 15.8°C | 11.9°C | 25.0°C | 7.9°C | 83 mm | 85% | 2.7 m/s | 4.9 |
| 2005 | 17.2°C | 13.9°C | 10.7°C | 25.0°C | 7.9°C | 51 mm | 85% | 2.9 m/s | 4.5 |
| 2004 | 16.0°C | 12.7°C | 9.4°C | 19.8°C | 6.1°C | 88 mm | 85% | 2.8 m/s | 4.6 |
| 2003 | 17.8°C | 14.6°C | 11.3°C | 23.2°C | 8.5°C | 116 mm | 87% | 3.2 m/s | 4.4 |
| 2002 | 15.9°C | 12.7°C | 9.6°C | 20.7°C | 6.5°C | 138 mm | 87% | 2.6 m/s | 3.9 |
| 2001 | 16.8°C | 13.4°C | 10.1°C | 21.5°C | 6.6°C | 119 mm | 86% | 2.9 m/s | 4.2 |
| 2000 | 17.1°C | 13.2°C | 9.3°C | 21.8°C | 5.7°C | 56 mm | 84% | 2.3 m/s | 4.9 |
| 1999 | 17.8°C | 14.2°C | 10.6°C | 23.6°C | 7.4°C | 111 mm | 86% | 3 m/s | 4.7 |
| 1998 | 15.2°C | 12.3°C | 9.4°C | 18.1°C | 7.1°C | 157 mm | 87% | 3.5 m/s | 4.5 |
| 1997 | 17.6°C | 14.1°C | 10.6°C | 22.4°C | 6.4°C | 109 mm | 85% | 2.8 m/s | 4.8 |
| 1996 | 16.5°C | 13.1°C | 9.6°C | 21.1°C | 6.2°C | 111 mm | 83% | 3 m/s | 4.8 |
| 1995 | 18.4°C | 14.4°C | 10.3°C | 24.6°C | 6.1°C | 89 mm | 84% | 3.3 m/s | 4.7 |
| 1994 | 17.5°C | 13.8°C | 10.1°C | 22.7°C | 7.0°C | 91 mm | 84% | 2.7 m/s | 4.6 |
| 1993 ❄️ | 14.7°C | 11.7°C | 8.7°C | 18.3°C | 4.6°C | 112 mm | 87% | 3.8 m/s | 4.4 |
| 1992 | 16.1°C | 12.7°C | 9.3°C | 20.0°C | 4.7°C | 105 mm | 85% | 3.5 m/s | 4.4 |
| 1991 | 18.2°C | 14.8°C | 11.5°C | 23.3°C | 8.7°C | 116 mm | 87% | 3.4 m/s | 4.3 |
| 1990 | 17.1°C | 13.4°C | 9.6°C | 21.5°C | 6.0°C | 89 mm | 83% | 3.5 m/s | 4.8 |
| 1989 | 19.2°C | 15.1°C | 11.0°C | 24.2°C | 6.1°C | 48 mm | 82% | 2.9 m/s | 5.5 |
| 1988 | 15.0°C | 12.1°C | 9.3°C | 17.8°C | 7.0°C | 185 mm | 86% | 3.7 m/s | 4.1 |
| 1987 | 16.9°C | 13.3°C | 9.7°C | 21.3°C | 6.1°C | 97 mm | 86% | 3.2 m/s | 4.3 |
| 1986 | 15.6°C | 12.3°C | 9.0°C | 21.0°C | 5.6°C | 79 mm | 85% | 3.5 m/s | 4 |
| 1985 🌧️ | 15.8°C | 12.6°C | 9.5°C | 22.1°C | 7.2°C | 190 mm | 87% | 3.5 m/s | 3.8 |
| 1984 | 18.5°C | 14.2°C | 9.9°C | 22.4°C | 4.9°C | 43 mm | 81% | 2.6 m/s | 5.1 |
| 1983 | 19.4°C | 15.3°C | 11.3°C | 25.5°C | 7.5°C | 33 mm | 83% | 2.6 m/s | — |
| 1982 | 18.3°C | 14.4°C | 10.4°C | 23.0°C | 7.1°C | 49 mm | 82% | 2.5 m/s | — |
| 1981 | 15.5°C | 12.3°C | 9.0°C | 19.4°C | 6.7°C | 112 mm | 86% | 3.3 m/s | — |
Actual recorded July data for each year, 1981–2025 — sourced from NASA POWER.
The average high in July is around 17.1°C with lows near 10.2°C (mean 13.7°C), based on 45 years of NASA POWER data.
July averages 109 mm of rainfall in Dumbarton, about average for rainfall. The wettest on record was 190 mm in 1985.
The hottest July reached 25.7°C in 2025. The coldest dipped to 4.6°C in 1993.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average July temperatures have risen by about 0.6°C. Daytime highs moved from 17.5°C to 17.9°C and overnight lows from 10°C to 10.8°C over the same span.
July is one of the warmer months of the year in Dumbarton and about average for rainfall, so plan for around 17.1°C daytime highs and 10.2°C at night.
Not quite — July is the 12th coolest month in Dumbarton, averaging 13.7°C.
For July in Dumbarton, pack light layers you can adjust through the day, with typical highs of 17.1°C and lows of 10.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in July averages 85% — quite humid.
Average wind speed in July is 3 m/s. The windiest July on record averaged 3.8 m/s (1993).
The wettest July on record was 1985 with 190 mm. On average, July sees 109 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 Dumbarton behaves each July, 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 July specifically, along with year-by-year records and how the month has changed over the decades.
