Cardiff Weather in September

September in Cardiff brings pleasant temperatures, with highs of 18°C (64°F) and nights dropping to 12°C (54°F). Rainfall is on the higher side this month, averaging around 90 mm (3.5 in), so keep a rain jacket handy.

Rainfall in Cardiff in September

Rain is expected on roughly 16 days, totalling around 90 mm (3.5 in) for the month. Expect a fairly normal spread of rainfall this month, with no particular pattern of very heavy or very persistent showers.

Temperature in Cardiff in September

If you're visiting Cardiff in September, expect highs of 18°C (64°F) and overnight lows around 12°C (54°F). September is typically considered a summer month. Even when the weather is stable, mornings and evenings can still feel distinctly cool. At 12°C (54°F) overnight, it can feel quite a bit cooler after dark. Worth packing something warmer for evenings, but the cooler temperatures are ideal for sleeping.

Sunshine in Cardiff in September

The city usually sees around 149 hours of sunlight, indicating a moderately sunny period.

Wind Speed in Cardiff in September

Wind speeds average 4 m/s (8 knots) during September. At this speed, expect moderate winds that can raise dust and move small branches. Since this is an average, some days have gentle light winds while others experience stronger breezes that are quite noticeable.

Average water temperature in September

The water temperature is 15°C (59°F), chilly, but perfectly fine for a swim if you're not too sensitive to cold water. A short wetsuit can make longer sessions more comfortable.

Our weather planner can help you find worldwide destinations with pleasant weather during this period. July and August typically offer the best weather for Cardiff.