September · United Kingdom
Best time to visit Cornwall in September Weather, crowds & prices
Weather in Cornwall in September
Average temperature 16°C, 109 mm of rain, about 7 days with 6+ hours of sunshine and 84% humidity — based on the five most recent complete years of ERA5 data (2021–2025).
September score
3.3/10
Ranked #6 of 12 months
- Avg temp
- 16°C
- Rainfall
- 109 mm
- Humidity
- 84%
- Days with 6h+ sun
- 7
- Crowd Density
- Moderate Crowds
- Average Expenses
- $$ · Moderate Cost ($$)
September in Cornwall scores 3.3/10 for beach and coastal travel - an above-average month (#6 of 12). Expect around 16°C, 109 mm of rain, and roughly 7 days with 6+ hours of sunshine this month.
Cornwall's granite cliffs, surf beaches and fishing harbours fill England's south-west tip.
September in Cornwall — off-season conditions
September averages 16°C (61°F), the range most people find easiest for walking a city all day without either overheating or losing daylight to weather.
At 109 mm this is a genuinely wet month: about 7 days with 6+ hours of sunshine in total, and outdoor plans need an indoor fallback.
It scores 3.3/10 here, 6th of 12 months, against 6.4/10 in the destination's best month.
Pack layers you can shed by midday plus one warm layer for the evening, a proper rain shell rather than an umbrella.
Figure on mid-season pricing, with crowds are moderate.
Flexible dates? August scores 3.1 points higher here — enough to change the trip.
Frequently asked
- What is the weather like in Cornwall in September?
- In September, Cornwall averages 16°C, 109 mm of rain, and about 7 days with 6+ hours of sunshine. Its climate-comfort score is 3.3/10.
- Is September a good time to visit Cornwall?
- September earns a 3.3/10 climate-comfort score. Use the year-round chart to weigh the weather against your budget and crowd preferences.
- How much does it rain in Cornwall in September?
- Expect about 109 mm of rain in September. Average humidity is 84% and there are about 7 days with 6+ hours of sunshine.
Curated in Cornwall
Tickets & experiences
Things to do in Cornwall
Cornwall, United Kingdom. Live activities and tours from GetYourGuide, matched to this destination.