Spring: Spring is a glorious time of year in Idaho! Wildflowers are in full bloom, and day-time temperatures are typically warm and in the 70s. However, the weather is quite variable and can range from cold and rainy with highs in the low 50s, to hot and dry with highs in the 90s. Obviously, the later in the spring the better your chances are for good weather. You should be prepared for both cold, rainy days and hot, sunny days. Bring layers.
Summer: Summer is typically hot and dry with day-time highs averaging in the 90s and lows in the 60s at night. Temperatures can reach 110 F or more during the hottest days of the summer. Fortunately, we are usually near refreshingly cool water to escape the heat. Sunscreen, a hat, and protective clothing are necessities.
Fall: September is spectacular here with warm days and cool nights and mostly nice weather. Rain is a possibility though, so be prepared with cool and wet weather gear. During the fall/winter fishing season, expect temperatures in the 30s to 50s during the day with rain and wind being distinct possibilities.
Please note: Weather at higher elevations above the river (which is where you'll be if you're hiking, biking, or horseback riding) can be significantly cooler even in the middle of the summer. Please bring appropriate attire if you plan to recreate at higher elevations.