Aquatic invertebrates experience variable temperature conditions throughout their life history, especially during the vulnerable life stage transition from aquatic to terrestrial habitats. Due to climate change, summer water and air temperatures have been rising, whereas spring water temperatures remain consistent from year-to-year due to the moderating influence of snow melt. Giant salmonflies (Pteronarcys californica) depend on spring water temperature cues to time their large, synchronous emergence in early summer, but it is unknown how variable temperatures after this springtime cue affect life-history traits. Using a laboratory experiment, we tested how changes in temperature in the weeks before and after emergence affect emergence timing, emergence success, and adult lifespans. We found that with each degree of warming during the weeks preceding emergence, the timing of emergence was 3.3 days earlier. However, emergence success was unaffected by higher water temperature within our test temperature range (13-23°C). On land, adult lifespans were shortened by increased air temperatures, especially when water temperatures during the juvenile stage had also been increased. The predicted lifespan was almost five times longer at the coldest air and water temperature combination than at the warmest (28 vs 6 days). However, even the shortest lifespan observed is not likely to prevent successful reproduction, since salmonflies can mate and oviposit within days of emergence. Our results indicate that although thermal changes in the weeks before and after emergence are not likely to limit salmonfly reproduction, shifting water and air temperatures could have consequences for riparian consumers by changing the timing and duration of the nutrients provided by these large-bodied aquatic insects.