Typical weather for late August: Average High is 86 degrees with the morning low at 53 (in town). Sunrise is at 7:06 am. Assuming it is a partly cloudy to clear day, temperatures should be good.
- At 7:00 am the temperature should be in the mid 40s with the humidity around 70% at the marathon start (6000 feet in elevation).
- At 9:00 am the temperature should be in the mid 50s with the humidity around 50%.
- At 11:00 am the temperature should be near 70 with the humidity around 40%.
If it is raining the temperature should be in the mid 50s. It is possible to see days over 100 degrees, but they are infrequent.
Idaho is a dry climate. If there are no clouds, the nights cool off quickly with the low temperatures occuring just before sunrise. Once the sun rises, the temperatures start rising quickly with high temperatures occuring around 3 pm.
Wind: On a normal day this time of year, there is a slight tailwind from the Gap (mile 19) until just before the finish line. Its hard to notice when you are running but you will notice the headwind when you turn into it for the last half mile.