March in Allentown averages a daily high of 10.4°C with nights around -1°C. Expect roughly 10.4 wet days totalling 88.4mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Allentown is May–June.
Based on ALLENTOWN LEHIGH VALLEY INTERNATIONAL AIRPORT, PA US (5.8km), 1995–2024. 30 years of March data.