Weather in Guernsey for September 2025
Until now, September 2025 in Guernsey is slightly cooler than the historical average by -0.9 °C.
The forecast for the next days in Guernsey predicts temperatures to be around 17 °C, close to the historical average.
In general, the average temperature in Guernsey at the beginning of September is 18.6 °C. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 16.4 °C by the end of September.
Guernsey in September brings notable rainfall, with an average of 17 rainy days and a total precipitation of 79 mm.
Temperatures
Rain 🌧️
Guernsey Weather September
Temperatures trend during September in Guernsey
September weather in Guernsey day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Light rain shower | 17° /16° | 7.6 mm | 4 | |
| 2 Sept. |  Partly cloudy | 18° /15° | 3.9 mm | 4 | |
| 3 Sept. |  Sunny | 19° /16° | 1.6 mm | 4 | |
| 4 Sept. | Sunny | 18° /16° | 1.5 mm | 5 | |
| 5 Sept. | Sunny | 19° /16° | 0.6 mm | 5 | |
| 6 Sept. | Patchy rain possible | 20° /16° | 0.6 mm | 5 | |
| 7 Sept. | Light rain shower | 19° /16° | 5.4 mm | 4 | |
| 8 Sept. | Partly cloudy | 19° /16° | 3.4 mm | 5 | |
| 9 Sept. | Patchy rain possible | 19° /16° | 2.1 mm | 4 | |
| 10 Sept. | Light rain shower | 18° /16° | 2.5 mm | 4 | |
| 11 Sept. | Partly cloudy | 17° /15° | 2.1 mm | 4 | |
| 12 Sept. |  Cloudy | 16° /14° | 2.7 mm | 4 | |
| 13 Sept. |  Overcast | 16° /14° | 1.4 mm | 4 | |
| 14 Sept. | Partly cloudy | 17° /14° | 0.5 mm | 5 | |
| 15 Sept. | Sunny | 18° /15° | 0.4 mm | 5 | |
| 16 Sept. | Patchy rain possible | 18° /16° | 0.7 mm | 4 | |
| 17 Sept. | Light rain shower | 18° /15° | 2.1 mm | 4 | |
| 18 Sept. | Patchy rain possible | 18° /17° | 0.4 mm | 1 | |
| 19 Sept. | Sunny | 19° /17° | 0 mm | 1.1 | |
| 20 Sept. | Partly cloudy | 18° /15° | 0.1 mm | 0.7 | |
| 21 Sept. |  Moderate rain | 16° /14° | 16.3 mm | 0.9 | |
| 22 Sept. |  Heavy rain | 16° /13° | 23.8 mm | 0.8 | |
| 23 Sept. | Cloudy | 15° /14° | 0 mm | 3 | |
| 24 Sept. | Patchy rain possible | 16° /15° | 0.1 mm | 4 | |
| 25 Sept. | Patchy rain possible | 16° /15° | 0.4 mm | 4 | |
| 26 Sept. | Sunny | 16° /14° | 0 mm | 5 | |
| 27 Sept. | Sunny | 17° /13° | 0 mm | 5 | |
| 28 Sept. | Patchy rain possible | 17° /15° | 0.5 mm | 4 | |
| 29 Sept. | Partly cloudy | 16° /15° | 0 mm | 5 | |
| 30 Sept. | Partly cloudy | 17° /16° | 0 mm | 5 | |
| Next | |||||
Guide for Guernsey in September
In Guernsey, September typically experiences mild and pleasant weather, making it an ideal time to visit this beautiful island. At the beginning of the month, the weather in Guernsey is generally warm with average temperatures around 18° during the day and 12° at night.
The island enjoys a moderate amount of sunshine, and the sea temperature remains relatively comfortable for swimming and water activities.
As the month progresses, the weather in Guernsey gradually transitions into autumn. By the end of September, temperatures may slightly decrease to around 16° during the day and 11° at night.
While the days remain relatively mild, the evenings become cooler, creating a refreshing atmosphere for outdoor strolls and al fresco dining.
Guernsey in September also experiences occasional rainfall, so it's advisable for visitors to pack a light waterproof jacket or umbrella. However, these showers are typically short-lived and do not significantly impact outdoor activities.
Overall, September offers a delightful blend of warm temperatures, comfortable sea conditions, and picturesque landscapes, making it an excellent time to explore the charming island of Guernsey.
Guernsey in September - FAQ
September rainfall patterns in Guernsey
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