There is a widespread belief that weather affects mood. However, few studies have investigated this link, and even less is known about individual differences in people's responses to the weather. In the current study, we sought to identify weather reactivity types by linking self-reported daily mood across 30 days with objective weather data. We identified four distinct types among 497 adolescents and replicated these types among their mothers. The types were labeled Summer Lovers (better mood with warmer and sunnier weather), Unaffected (weak associations between weather and mood), Summer Haters (worse mood with warmer and sunnier weather), and Rain Haters (particularly bad mood on rainy days). In addition, intergenerational concordance effects were found for two of these types, suggesting that weather reactivity may run in the family. Overall, the large individual differences in how people's moods were affected by weather reconciles the discrepancy between the generally held beliefs that weather has a substantive effect on mood and findings from previous research indicating that effects of weather on mood are limited or absent. © 2011 American Psychological Association.