Interdecadal Increase in Spring‐To‐Summer Persistence of Central American Precipitation Anomalies

Abstract Central American agriculture and ecosystems are acutely sensitive to rainfall that spans the spring‐summer growing window, yet most studies still evaluate each season in isolation. Here we demonstrate that, since the 2000s, Central American precipitation anomalies in spring have become more likely to persist into summer‐a shift that single‐season analyses overlook. This lengthened persistence arises from a regime change in which multi‐month “persistent events” now dominate over the previously common “transitional events.” Persistent events are anchored by coupling between warm tropical Atlantic (TA) and cold tropical Central‐Eastern Pacific (TCEP) sea surface temperature (SST) anomalies that sustains cyclonic circulation, whereas transitional events rely on rapid TCEP SST reversals that disrupt rainfall anomalies. Strengthened Atlantic influences on Pacific climate since 2000 have prolonged Pacific SST persistence, boosting persistent‐event frequency and extending springtime rainfall anomalies into summer. This cross‐seasonal persistence heightens risks to water, food and biodiversity in Central America.