August in Nampa averages a daily high of 32.8°C with nights around 16.4°C. Rain is rare — about 2.3 wet days and 6.7mm across the month. Generally workable, with some weather to plan around.
Across the year, the best time to visit Nampa is June.
Based on BOISE AIR TERMINAL, ID US (26.2km), 1995–2024. 30 years of August data.