The ideal time to river raft the Wenatchee River is between May and July.
May is peak, snow-melt runoff, so the water will be cold, the air temperature in the 70s and the water level can be moderate to high.
June is nice because the ambient temperature has risen considerably, while the river levels usually are still good enough to provide some exciting white water.
July is typically low and slow, but the weather is reaching the high 90s, so rafting continues to be fun, but more memorable due to water-fighting and voluntary swims.
Orion River Rafting provides daily, unhurried river trips out of Leavenworth, Washington. Established 1978. http://orionexp.com
"Spring mountain snowmelt creates excellent rafting conditions in the Wenatchee River."
- Leavenworth, Washington - A Great Place to Visit (view on Google Sidewiki)