UV Index North America
Real-time UV index for cities across North America. From sunny Florida to the Canadian Rockies — see where UV levels are highest today.
North America UV summary
Top countries
| Country | Now | Max today | WHO UV |
|---|---|---|---|
| United States | 9 | 10 | 2,736 |
| Mexico | 5 | 10 | 4,974 |
| Aruba | 1 | 10 | - |
| Dominican Republic | 0 | 10 | 4,880 |
| Barbados | 0 | 10 | 5,787 |
| Belize | 2 | 9 | 4,639 |
| Cuba | 1 | 9 | 4,401 |
| Jamaica | 1 | 9 | 4,942 |
| Puerto Rico | 0 | 9 | - |
| Costa Rica | 1 | 8 | 4,884 |
Top cities
| City | Now | Max today | Clear sky |
|---|---|---|---|
| Wailea-Makena | 9 | 10 | 10 |
| Kīhei | 9 | 10 | 10 |
| Makakilo | 8 | 10 | 10 |
| Honolulu | 8 | 10 | 10 |
| Mexico City | 5 | 10 | 11 |
| Cabo San Lucas | 5 | 10 | 10 |
| Puerto Vallarta | 4 | 10 | 10 |
| Oranjestad | 1 | 10 | 11 |
| Punta Cana | 0 | 10 | 10 |
| Bridgetown | 0 | 10 | 11 |
UV radiation overview
North America extends to within roughly 10° of latitude of both the equator and the North Pole, producing one of the planet's widest single-continent UV gradients. Caribbean nations near 7°N receive year-round tropical UV, while northern Canada and central Greenland — where vast snow and ice cover persists — sit above 70°N with weak winter insolation but strongly reflective summer surfaces. The official UV index, used to communicate this risk, is a linear scale: a reading of 12 carries twice the sunburning intensity of a reading of 6.
Two amplifiers stand out across the continent. Mexico and the southwestern United States contain extensive high-altitude plateaus where thinner atmosphere lets more UV reach the ground. Snow- and ice-covered regions of Canada, Alaska, and Greenland reflect a large fraction of incoming UV back into the atmosphere — the UV index forecast model explicitly accounts for this surface reflectivity factor. Combined with stratospheric ozone variability, summertime UV index values now routinely reach the double digits across mountain and tropical zones.
Canada was the first country in the world to issue official next-day UV index forecasts when Environment Canada launched the service on 27 May 1992; the World Health Organization and World Meteorological Organization standardized the global UV index in 1994.
