Cardiff
September
Weather in Cardiff for September 2025
Your guide to Cardiff weather in September - trends and predictions
In general, the average temperature in Cardiff at the beginning of September is 20.4 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 15.7 °C by the end of September.
Expect significant rainfall in Cardiff during September, with an average of 16 rainy days.
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14
Dry days
16
Rainy days
0
Snow days
19°/13°
Temperatures
23 km/h
Avg max wind
81 %
Avg humidity
Cardiff in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  20° | 2  20° | 3 20° | 4  20° | 5 20° | 6 21° | 7 22° |
| 8 21° | 9 21° | 10 19° | 11 17° | 12  15° | 13  16° | 14  16° |
| 15 19° | 16 18° | 17 18° | 18  19° | 19 20° | 20 19° | 21 18° |
| 22 17° | 23 16° | 24 17° | 25 16° | 26 16° | 27 15° | 28 15° |
| 29 15° | 30 16° |
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Temperatures trend during September in Cardiff
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. | Light rain shower | 20° /13° | 2.5 mm | 5 | |
| 2 Sept. | Partly cloudy | 20° /12° | 0.3 mm | 5 | |
| 3 Sept. | Partly cloudy | 20° /13° | 1 mm | 5 | |
| 4 Sept. | Sunny | 20° /13° | 0.1 mm | 5 | |
| 5 Sept. | Sunny | 20° /13° | 10.8 mm | 5 | |
| 6 Sept. | Partly cloudy | 21° /15° | 4.4 mm | 5 | |
| 7 Sept. | Sunny | 22° /15° | 0.2 mm | 5 | |
| 8 Sept. | Partly cloudy | 21° /15° | 10.5 mm | 5 | |
| 9 Sept. | Sunny | 21° /13° | 0.7 mm | 6 | |
| 10 Sept. | Partly cloudy | 19° /12° | 0.9 mm | 5 | |
| 11 Sept. | Patchy rain possible | 17° /11° | 0.2 mm | 4 | |
| 12 Sept. | Mist | 15° /9° | 0.5 mm | 4 | |
| 13 Sept. | Cloudy | 16° /8° | 0 mm | 4 | |
| 14 Sept. | Overcast | 16° /10° | 0 mm | 5 | |
| 15 Sept. | Sunny | 19° /10° | 0 mm | 5 | |
| 16 Sept. | Light rain shower | 18° /11° | 0.7 mm | 5 | |
| 17 Sept. | Light rain shower | 18° /11° | 5.8 mm | 5 | |
| 18 Sept. | Light drizzle | 19° /12° | 0.8 mm | 5 | |
| 19 Sept. | Light rain shower | 20° /13° | 2.9 mm | 5 | |
| 20 Sept. | Light rain shower | 19° /12° | 10.2 mm | 5 | |
| 21 Sept. | Light rain shower | 18° /10° | 6.3 mm | 5 | |
| 22 Sept. | Light rain shower | 17° /10° | 4.5 mm | 4 | |
| 23 Sept. | Patchy rain possible | 16° /10° | 1.1 mm | 4 | |
| 24 Sept. | Light rain shower | 17° /12° | 5.4 mm | 4 | |
| 25 Sept. | Patchy rain possible | 16° /11° | 4.2 mm | 4 | |
| 26 Sept. | Light rain shower | 16° /11° | 6 mm | 4 | |
| 27 Sept. | Light rain shower | 15° /9° | 5.7 mm | 4 | |
| 28 Sept. | Light rain | 15° /9° | 2.8 mm | 4 | |
| 29 Sept. | Partly cloudy | 15° /9° | 8.4 mm | 4 | |
| 30 Sept. | Patchy rain possible | 16° /10° | 4.5 mm | 4 | |
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Important Notice
Our weather forecast for Cardiff in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Cardiff forecast closer to your planned date for the most up-to-date weather information.
Cardiff in September - FAQ
What are the expected maximum and minimum temperatures in Cardiff during September?
Enjoy moderate daytime temperatures of up to 19° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Cardiff during September?
Moderate rainfall is anticipated in Cardiff during September, with a total of 72.7 mm spread over approximately 16 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Cardiff during September?
The average wind speed in Cardiff during September is 23 km/h, suggesting breezy to windy conditions, depending on your activities.
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