August in Bethlehem averages a daily high of 28.7°C with nights around 16.9°C. Expect roughly 10.4 wet days totalling 118.7mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Bethlehem is May–June.
Based on ALLENTOWN LEHIGH VALLEY INTERNATIONAL AIRPORT, PA US (7km), 1995–2024. 30 years of August data.