March in Costa Mesa averages a daily high of 17.6°C with nights around 11.7°C. Expect roughly 4.8 wet days totalling 30.4mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Costa Mesa is May–November.
Based on NEWPORT BEACH HARBOR, CA US (5.3km), 1995–2024. 26 years of March data.