Portmarnock Weather in September

September in Portmarnock brings moderate temperatures, with highs of 17°C (63°F) and nights dropping to 12°C (54°F). Rainfall is on the higher side this month, averaging around 78 mm (3.1 in), so keep a rain jacket handy.

Rainfall in Portmarnock in September

The climate data from previous years indicates about 15 days of rain, averaging 78 mm (3.1 in) for the month. The rainfall pattern this month is fairly balanced. Showers tend to be moderate rather than extreme.

Temperature in Portmarnock in September

If you're visiting Portmarnock in September, expect highs of 17°C (63°F) and overnight lows around 12°C (54°F). During September, you'll experience the summer season. 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 Portmarnock in September

The month experiences a moderate amount of sunlight, with 128 hours of sunshine. This provides a nice balance between sunshine and clouds.

Wind Speed in Portmarnock 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

With water at 15°C (59°F), it's on the cooler side. Keen swimmers won't be put off, but those who prefer warm water may find it less enjoyable.

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