Dumbarton Weather & Climate: Best Time to Visit

In Dumbarton, temperatures differ significantly between summer and winter months. On average, daytime temperatures range from a pleasant 19°C (66°F) in July to a chilly 8°C (46°F) in December.

Nighttime temperatures range from 11°C (52°F) in July to 2°C (36°F) in December.

Check out our detailed temperature page for more information.

Temperature ranges by month

Dumbarton experiences significant rain/snowfall throughout the year, averaging 1520 mm (60 in) of precipitation annually. The amount of precipitation varies moderately throughout the year. The wettest month, January, sees around 158 mm (6.2 in) of rainfall, perfect for those who enjoy a bit of rain now and then. The driest month, May, still receives a respectable 96 mm (3.8 in) of rainfall. For more details, please visit our Dumbarton Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

In Dumbarton, summer days are longer and more sunny, with daily sunshine hours peaking at 6.3 hours in May. As the darker season arrives, the brightness of the sun becomes less. January sees a soft sun for only 1.2 hours per average day.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

Daily percentage of sunshine

The relative humidity is high throughout the year in Dumbarton.

The city experiences its highest humidity in January, reaching 87%. In May, the humidity drops to its lowest level at 68%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year