Stoneflies are among the few aquatic insects with representatives that complete their life cycles during winter, emerging from streams as active, reproductive adults. In Minnesota, Allocapnia spp. Claasen, 1928, are among the most common winter-emerging insects. We examined longevity of adult Allocapnia at varying low temperatures and across sex and species. Adult Allocapnia (n = 212) were collected from two spring-fed streams in Minnesota, USA, during winter 2024 and separated into four treatment groups: -6°C, 0°C, +6°C, or +12°C. Specimens were examined daily until death to assess longevity from collection. We found that Allocapnia have prolonged adult lifespans at 0°C as compared to warmer temperatures. At 0°C, A. granulata females and males, respectively, exhibited mean longevities of 42.7 and 21.9 days; comparatively, mean longevity for both sexes at 12°C was approximately 13 days. Similarly, A. pygmaea exhibited mean longevities of 28.0 and 18.8 days for females and males at 0°C, with mean longevities declining to approximately 6-7 days at 12°C. Results suggest an even longer adult lifespan at -6°C. Our work provides insights into how temperature increases due to climate change may impact survival of these winter active species, and subsequently, organisms that feed upon them.