April in Harlingen averages a daily high of 29.7°C with nights around 18.6°C. Expect roughly 4.9 wet days totalling 39.8mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Harlingen is November–March.
Based on HARLINGEN, TX US (2.7km), 1995–2024. 27 years of April data.