Cornwall Weather in September

September in Cornwall averages 20°C (68°F) during the day and 12°C (54°F) at night. Quite a bit of rainfall is typical this month, with around 102 mm (4 in) on average. An umbrella is a good idea.

Rainfall in Cornwall in September

Records from the past 30 years suggest around 12 days of rain, with 102 mm (4 in) average for the month. The rain this month tends to fall in heavier spells rather than light drizzle. When it rains, showers can be significant.

Temperature in Cornwall in September

If you're visiting Cornwall in September, expect highs of 20°C (68°F) and overnight lows around 12°C (54°F). September is typically considered a summer month. A light jacket or extra layer can be useful, especially outside the warmest hours of the day. With lows of 12°C (54°F), nights are cool. If you're out after dark, an extra layer will keep you comfortable. The cooler air at night is also great for getting a good rest.

Sunshine in Cornwall in September

The city usually sees around 183 hours of sunlight, indicating a moderately sunny period.

If you prefer dry days with pleasant temperatures, June, July and August typically offer the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.