September in Irun averages a daily high of 24.3°C with nights around 15.5°C. Expect roughly 11.9 wet days totalling 146.5mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Irun is May–October.
Based on SAN SEBASTIAN FUENTERRABIA, SP (2.4km), 1995–2024. 24 years of September data.