April in Lāhījān averages a daily high of 17°C with nights around 12.4°C. Expect roughly 8.5 wet days totalling 55.9mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Lāhījān is May–June.
Based on ANZALI, IR (56.1km), 1995–2024. 21 years of April data.