This article examines the influence of climate variability and accelerated forest thinning on runoff in ponderosa pine forests in the Salt and Verde River watersheds in central Arizona. The effects of thinning treatments were examined over 15-, 25-, and 35-year periods. Over the course of treatments, cumulative runoff on thinned forests was about 20% greater than un-thinned forests, regardless of whether forest thinning occurred in a dry or wet period. Runoff gains were temporary and modest when compared to total annual flows in Salt-Verde (≤3%). Nonetheless, additional runoff from thinning could help offset projected declines in snowpack due to warming, augment river flows on a seasonal basis, improve conditions for water dependent natural resources, as well as provide incidental benefits to downstream users.