Jacksonville, FL

Jacksonville covers more land area than any other city in the contiguous US, and its flood score—86, at the 94th national percentile—reflects that geography more than most buyers expect. The St. Johns River does not behave like a coastal surge pathway. In 2017, Hurricane Irma produced flooding well inland across neighborhoods that market themselves without any coastal framing. That event remains the city's clearest proof that river exposure and surge exposure are different problems requiring different diligence. Our read: the San Marco and Mandarin submarkets illustrate this divide directly. San Marco's river-adjacent parcels see sharp differences block to block—elevation, drainage connection, and prior flood claims can diverge by the lot. Mandarin's creek and tributary system surprises buyers who focused only on direct waterfront status. Southside's rapid development is shifting runoff patterns in ways that older flood maps do not yet fully capture. Insurance premiums range from $2,400 to $6,200 annually, with riverfront lots underwriting differently from inland subdivisions—sometimes dramatically so. Newer roofs can materially improve pricing outcomes. The 2023 record heat season extended the city's risk discussion beyond storm season: cooling costs and humidity added sustained operating pressure for older housing without modern HVAC systems. Jacksonville's hurricane score sits at the 92nd national percentile—high, but below the extreme banding of South Florida—which can give buyers false confidence about the overall picture. The real exposure here is layered: river flooding, creek overflow, repetitive-loss history, and progressive heat loading form the actual diligence checklist.

— Open Data Collective