Climate refugia are areas that remain relatively stable amid climate variability and change, making them increasingly prioritized worldwide for safeguarding biodiversity and ecosystem services. Wet and cool microenvironments often serve as climate refugia in semi-arid regions. However, springs—locations where groundwater reaches the Earth’s surface – remain underexplored in climate refugia science. This study investigated the potential of spring ecosystems as climate refugia in a semi-arid mountainous region of central Idaho, U.S.A. Using high-resolution PlanetScope imagery (2017–2024), we derived seasonal phenophases from a Normalized Difference Vegetation Index (NDVI) time series to assess ecological stability at 40 springs and surrounding non-spring areas. Springs were considered climate refugia if they had lower phenological variability and sensitivity to interannual climate variability relative to non-springs. We found that springs exhibited significantly lower interannual variability in end of growing season (EOS) timing (24 days less than non-springs). Higher annual climate water balance, reflecting greater precipitation relative to potential evapotranspiration, corresponded with later EOS timing for both springs (p < 0.001) and non-springs (p < 0.001), but springs were less sensitive to annual CWB variability as shown by the lower effect size (β = 0.49 vs. β = 0.83). Springs phenology showed weak (p > 0.05) associations with topographic factors, underscoring their independence from topographically driven refugia. Our findings highlight springs as climate refugia, due to their buffering of water limitations that stabilize late season phenology. Under climate change, water deficits will become more severe and accelerate the depletion of summer soil moisture in arid and semi-arid regions of the globe, making climate refugia like springs increasingly important. Future research should examine groundwater recharge processes to monitor the inputs to spring refugial stability across a range of climate conditions and geographies.