As of 10:55 AM EDT on March 18, 2026, all 2 cities in Nantucket County, MA in our database have a UV Index reading of Low. The city with the highest UV Index reading right now is Siasconset, MA with a reading of 2.1.
Over the next 24 hours, the highest UV Index reading in Nantucket County, MA is expected to be 3.2 in Siasconset between 1:00 PM - 2:00 PM EDT today.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |