Caribbean Heat Stress & WBGT

Caribbean Heat Stress: Why WBGT Matters Region-Wide

Across the Caribbean, heat stress is intensifying, and because so much of the region's life happens outdoors in full sun, WBGT is the metric that fits. It measures humidity and radiant sun, not just temperature, which is exactly what a hot, humid, ocean-bright region needs. ClimaSafe starts this work in the U.S. Virgin Islands.

Last updated July 9, 2026 · Live data refreshes every 15 min

The Caribbean's climate is defined by heat, humidity, and sun in near-constant supply. That is also the precise recipe for heat stress on the human body, and research indicates the region is trending hotter, with more frequent and intense hot, humid spells. For workers, athletes, students, residents, and the visitors the region's economy depends on, understanding heat as more than a temperature reading is becoming essential.

Why the region needs more than a thermometer

In much of the Caribbean, the real question is never "how warm is the air?", it is "is it safe to be working, training, or hiking in the sun right now?" TheWet Bulb Globe Temperature answers that question by combining humidity, wind, and radiant sun with temperature. The familiar heat index, which assumes shade and ignores wind, systematically under-warns for the outdoor, full-sun life the region actually lives.

Starting in the U.S. Virgin Islands

ClimaSafe brings a live, physically-grounded WBGT map and local guidance toSt. Thomas,St. John, andSt. Croix, the same three islands, three very different heat characters. The physics behind it (theLiljegren model) is universal, and the approach is built to extend. The USVI is where it begins, not where it has to end.

The through-line. Whether you're on a St. Croix job site, a St. John trail, or another island entirely, the safe-outdoor-activity question is the same, and WBGT is the number built to answer it.

Sources & further reading

Vanos, J., et al. (2023). A physiological approach for assessing human survivability and liveability to heat in a changing climate. Nature Communications. doi:10.1038/s41467-023-43121-5
Kong, Q., & Huber, M. (2022). Explicit Calculations of WBGT. Earth's Future. doi:10.1029/2021EF002334
U.S. NWS. WBGT. weather.gov/ict/WBGT

Frequently asked questions

Is heat stress getting worse in the Caribbean?

Peer-reviewed research points to rising heat stress across the tropics, with more frequent and intense hot, humid conditions. For a small, ocean-surrounded region where much of life happens outdoors, that makes a heat metric like WBGT, which captures humidity and sun, not just temperature, increasingly important.

Why is WBGT especially relevant in the Caribbean?

The Caribbean is hot, humid, and sunny, and much of its work, sport, and tourism happens outdoors in full sun. Those are exactly the conditions where the shade-only heat index under-warns and WBGT gives a truer picture of heat stress on the body.

Does ClimaSafe cover the whole Caribbean?

ClimaSafe currently focuses on the U.S. Virgin Islands, where it provides a live, island-by-island WBGT map and local guidance. The same physics applies region-wide, and the approach is designed to extend to other Caribbean locations over time.