Live UV forecast for 3,407 cities
United States stretches from 19.7299° to 64.8378° latitude (Northern hemisphere), so UV conditions differ a lot from region to region. The clear-sky UV index reaches ≈ 9.3 in Hilo (peak in May), while in Fairbanks the yearly maximum is only ≈ 5.7.
| Zone | Cities | J | F | M | A | M | J | J | A | S | O | N | D | Peak |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tropical | 47 | 6.4 | 7.2 | 8.2 | 9 | 9.2 | 9.2 | 9.2 | 9.1 | 8.7 | 7.9 | 7 | 6.3 | 9.2 |
| Subtropical | 1013 | 4.4 | 5.3 | 6.6 | 7.7 | 8.2 | 8.4 | 8.3 | 7.9 | 7.3 | 6.2 | 5.1 | 4.3 | 8.4 |
| Temperate | 2342 | 3.1 | 4.1 | 5.6 | 6.9 | 7.6 | 8 | 7.8 | 7.3 | 6.3 | 5 | 3.8 | 3 | 8 |
| High-latitude | 5 | 0.5 | 1.3 | 2.7 | 4.3 | 5.4 | 6 | 5.8 | 4.9 | 3.6 | 2.2 | 1.1 | 0.4 | 6 |
Calculated clear-sky noon peaks at the average latitude of each zone. Real values vary with clouds, altitude and ozone.
Using New York City as a reference: the UV index reaches 6+ in April, May, June, July, August and September. In the sunniest zones (see table) SPF 30–50+ is needed almost year-round; in the mildest — only in late spring and summer.
The calculated clear-sky maximum is ≈ 9.3 — in Hilo around May. Values above this occur only near the equator and in high mountains.
Hilo (peak ≈ 9.3), followed by 'Ewa Beach and 'Ewa Beach-Iroquois Point. The mildest sun is in Fairbanks (max ≈ 5.7).
In New York City and similar latitudes the UV reaches 6+ in April, May, June, July, August and September: use SPF 30–50+ on sunny days. Protection is advised from UV 3.
No — the local maximum is ≈ 9.3. UV 11+ occurs only near the equator, in deserts and high mountains.