UC Irvine

Heat waves in California are occurring with increasing frequency, duration, and intensity, largely due to climate change. Furthermore, the burden of extreme heat disproportionately affects various communities both geographically and socioeconomically. As a result, understanding how heat is discussed on social media is critical for informing the design of public health interventions. This study involved a spatiotemporal analysis of heat-related tweets (N = 24,598) posted across California between April and October from 2016 to 2022. Poisson regression models were used to examine county-level counts of heat tweets, with population size included as an offset term in the model while logistic regression models estimated the probability that a heat tweet reflected coping or life impact (LI) themes. A different set of logistic regression models were fit to examine the effect of socio-demographic and housing variables on the likelihood of heat tweets expressing positive and negative sentiment, and on the likelihood of expressing coping or LIs. Explanatory variables were derived mostly from the American Community Survey and the Healthy Places Index. Sensitive housing (percentage of households living in an RV, van, or boat) and income predicted posting of heat tweets about coping, whereas income and percentage of active commuters predicted posting of heat tweets about LIs. Percentage of active commuters, tree canopy, and sensitive housing predicted negative heat tweets. Counties with greater proportion of Hispanic population in California also appeared vulnerable, showing a modest tendency toward greater LI and fewer coping-related heat tweets. These findings suggest that public health interventions should prioritize outreach to individuals living in sensitive housing, with an emphasis on indoor heat mitigation strategies. Overall, results demonstrate the value of social media heat discourse as a complementary tool for identifying vulnerable communities and informing targeted extreme heat awareness campaigns.