Florida's summer has arrived — and with it, the most dangerous period of the year for dengue fever transmission in the Sunshine State. Miami-Dade County health officials have maintained an active mosquito-borne illness alert through June 2026, directing residents to intensify personal protection measures as the combination of heat, humidity, and standing water creates optimal breeding conditions for Aedes aegypti mosquitoes, the primary vector of dengue virus. The alert comes as CDC surveillance data confirm a 359 percent rise in U.S. dengue activity compared to historical averages, with thousands of cases reported nationally and increasing evidence that Florida's locally acquired transmission risk is higher in 2026 than in most prior years.
The timing carries particular weight this year. While travel-associated dengue cases account for the majority of Florida's annual burden — 431 travel-associated dengue cases were reported statewide in 2025 according to the Florida Department of Health Arbovirus Surveillance Report — the state's history of local transmission during summer months is well established. In 2023, Florida reported 154 locally acquired dengue cases, the vast majority concentrated in Miami-Dade County. In 2024, the CDC reported 91 locally acquired cases statewide in Florida as part of a record-breaking national year of dengue activity. The 2026 peak season is only beginning.
