More rain falls on Dumbarton than on 93% of UK towns: 1,305 mm (51 in) a year
The depth of winter brings overnight lows near 1.8°C (35°F). Wet weather is most frequent in January and least in April. By July afternoons alone, it runs cooler than 87% of UK towns. Homes need heating from October to April, the months averaging under 10°C.
Met Office 1991–2020 averages for the town itself.
A year in Dumbarton at a glance
Each month’s typical high and low, in °C.
What a year in Dumbarton feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 1,305 mm of rain a year
January is the wettest month and April the driest. About 41 days a year bring 10 mm (0.4 in) or more. 8th wettest of 8 West Dunbartonshire towns of 2,500+.
Rain by month
Millimetres
Sunshine by month
Hours of bright sunshine at Paisley
40 air frosts and 3 days of 25°C a year
On about 40 nights a year the air drops below freezing, and on about under 1 days it stays below freezing all day. About 3 days a year reach 25°C (77°F).
Day counts are 1991–2020 averages from the Met Office’s 2 km grid. The Met Office calls a day of 25°C or more a summer day and a night below 0°C an air frost; ground frosts, on grass, come more often.
The Met Office station at Paisley
Paisley is 8.7 miles south-east of Dumbarton, 32 m (105 ft) above sea level. It is the nearest of the 37 long-running stations the Met Office publishes in full.
| Month | High | Low | Rain | Air frosts | Sun (hours) |
|---|---|---|---|---|---|
| January | 7.1°C | 1.9°C | 147 mm | 8.5 | 39 |
| February | 7.8°C | 2.1°C | 111 mm | 7.3 | 69 |
| March | 9.9°C | 3.2°C | 100 mm | 4.3 | 103 |
| April | 12.9°C | 5.1°C | 72 mm | 0.9 | 133 |
| May | 16.1°C | 7.4°C | 63 mm | 0.1 | 184 |
| June | 18.3°C | 10.2°C | 67 mm | 0.0 | 161 |
| July | 19.7°C | 12.1°C | 76 mm | 0.0 | 149 |
| August | 19.5°C | 11.9°C | 90 mm | 0.0 | 151 |
| September | 16.7°C | 9.9°C | 99 mm | 0.0 | 116 |
| October | 12.9°C | 6.8°C | 134 mm | 0.9 | 89 |
| November | 9.6°C | 4.3°C | 133 mm | 3.6 | 54 |
| December | 6.8°C | 1.5°C | 136 mm | 9.7 | 36 |
| Year | 13.1°C | 6.4°C | 1,229 mm | 35 | 1,282 |
Met Office historic station data, Paisley, 1991–2020 months averaged (a month needs 20 of the 30 years; estimated values counted, missing months left out). Sunshine: Campbell-Stokes recorder.
How Dumbarton compares
Against the 2,537 towns and cities of 2,500 or more across the UK, each with its own Met Office averages, and its place among West Dunbartonshire towns that size.
Nearby towns’ climate
The nearest towns of 1,000+ within 12 miles: a hill, a valley or the sea can make a real difference over a few miles.
| Town | July high | January low | Rain a year |
|---|---|---|---|
| Dumbarton | 19.3°C | 1.8°C | 1,305 mm |
| Bonhill 2.3 mi | 19.4°C about the same | 1.5°C about the same | 1,506 mm |
| Alexandria 3.2 mi | 19.2°C about the same | 2.0°C about the same | 1,497 mm |
| Bishopton 3.7 mi | 19.2°C about the same | 1.4°C about the same | 1,360 mm |
| Balloch and Haldane 3.8 mi | 19.4°C about the same | 2.1°C about the same | 1,482 mm |
| Bowling and Old Kilpatrick 4.4 mi | 18.2°C 1.1°C cooler | 1.7°C about the same | 1,431 mm |
| Port Glasgow 4.4 mi | 18.8°C about the same | 1.7°C about the same | 1,701 mm |
Dumbarton weather by month
Average daily high and low, mean temperature and rain, 1991–2020, for the town itself (the Met Office’s HadUK-Grid).
| Month | High | Low | Mean | Rain |
|---|---|---|---|---|
| January | 6.7°C 44°F | 1.8°C 35°F | 4.3°C | 162 mm 6.4 in |
| February | 7.4°C 45°F | 1.9°C 35°F | 4.7°C | 126 mm 5.0 in |
| March | 9.2°C 49°F | 2.9°C 37°F | 6.0°C | 101 mm 4.0 in |
| April | 12.2°C 54°F | 4.5°C 40°F | 8.3°C | 68 mm 2.7 in |
| May | 15.4°C 60°F | 6.9°C 44°F | 11.0°C | 72 mm 2.9 in |
| June | 17.8°C 64°F | 9.7°C 49°F | 13.6°C | 77 mm 3.0 in |
| July | 19.3°C 67°F | 11.5°C 53°F | 15.2°C | 80 mm 3.1 in |
| August | 18.8°C 66°F | 11.4°C 52°F | 15.0°C | 99 mm 3.9 in |
| September | 16.3°C 61°F | 9.6°C 49°F | 12.9°C | 100 mm 3.9 in |
| October | 12.7°C 55°F | 6.7°C 44°F | 9.7°C | 143 mm 5.6 in |
| November | 9.2°C 49°F | 4.0°C 39°F | 6.6°C | 133 mm 5.2 in |
| December | 7.0°C 45°F | 1.8°C 35°F | 4.4°C | 144 mm 5.7 in |
| Year | 12.7°C | 6.0°C | 9.3°C | 1,305 mm |
Where Dumbarton’s numbers come from
Averages over 30 years, not a forecast.
- Mean temperature, rain and day counts: HadUK-Grid 1991–2020 averages for the 1 Met Office 2 km grid square whose centre lies inside Dumbarton’s locality.
- Highs and lows: the Met Office publishes average daily maxima and minima on its 12 km grid; each is moved by the difference between the town’s 2 km mean temperature and the 12 km square’s, which carries the town’s own height and setting over.
- Weather station and sunshine: Met Office historic station data for Paisley, 8.7 miles away, months of 1991–2020 averaged.
- Comparisons: every town and city of 2,500 or more across the UK, all four nations, read the same way.
Met Office HadUK-Grid · Met Office Climate Data Portal · Historic station data. Open Government Licence v3.0.
Questions about Dumbarton’s climate
How warm does Dumbarton get in summer?
July is the warmest month, with average highs of 19.3°C (67°F). About 3 days a year reach 25°C (77°F), fewer than 84% of UK towns.
How cold does Dumbarton get in winter?
December nights average 1.8°C (35°F). The air drops below freezing on about 40 nights a year, and about under 1 days a year stay below freezing all day.
How much rain does Dumbarton get?
About 1,305 mm (51 in) a year, more than 93% of UK towns. January is the wettest month (162 mm) and April the driest (68 mm).
How sunny is it?
The nearest Met Office station with a sunshine record, Paisley (8.7 miles away), averages 1,282 hours of bright sunshine a year. Sunshine isn’t on the town grid, so this is the station’s figure.
Where do these figures come from?
The Met Office’s HadUK-Grid 1991–2020 averages, which turn thousands of weather stations into a map of the UK in 2 km squares; the page reads the squares inside Dumbarton. They are 30-year averages, not a forecast.
Contains Met Office data © Crown copyright 2026, Open Government Licence v3.0. HadUK-Grid 1991–2020 averages via the Met Office Climate Data Portal; station averages from Met Office historic station data. Today’s forecast for Dumbarton →
Contains public sector information licensed under the Open Government Licence v3.0. Contains HM Land Registry data © Crown copyright and database right 2026. Contains OS data © Crown copyright and database right 2026 (ONS boundaries). Northern Ireland: Source: NISRA; contains Land & Property Services data and Ordnance Survey of Northern Ireland information, © Crown copyright, licensed under the Open Government Licence v3.0. Scotland: contains National Records of Scotland data, Registers of Scotland data and SEPA data, © Crown copyright / © SEPA 2025, licensed under the Open Government Licence v3.0.