Vitamin D in Massachusetts in January: sun, UV and what to expect
Too cold Too cold here in January: afternoon highs average only 3.9°C, which is too chilly for sunbathing in light clothing. Try another month or a warmer destination.
0.5 hsun window (UV 2.5+)
2.0peak UV Index
–to a full dose
4°Cafternoon high
12/30rainy days
17/30sunny days
Open Massachusetts for January on the map Find stays in Massachusetts
How long in the sun in January?
- Even at midday the UV Index stays below 2.5 for most of January, so sunbathing makes little or no vitamin D. Oily fish, fortified food or a supplement matter more. Ask your doctor.
- Water, sand and light surfaces reflect UV, so at the beach you get a little more sun than the number suggests, for the good and the bad.
| Skin type | Full dose, age 30 | Full dose, age 65 | Time to burn |
|---|---|---|---|
| Type I | – | – | – |
| Type II | – | – | – |
| Type III | – | – | – |
| Type IV | – | – | – |
| Type V | – | – | – |
| Type VI | – | – | – |
Minutes at midday for about 1,000 IU of vitamin D with a quarter of the body bare, at Martha's Vineyard, the median coastal place. Time to burn is the time to reach one minimal erythemal dose and does not depend on age. A rough planning guide, not medical advice.
Places in Massachusetts in January
| Place | Rating | Sun window | Full dose | Afternoon high | Rainy days |
|---|---|---|---|---|---|
| Cape Cod | Too cold | 0.6 h | – | 5°C | 15/30 |
| Provincetown | Too cold | 0.4 h | – | 3°C | 11/30 |
| Nantucket | Too cold | 0.8 h | – | 4°C | 11/30 |
| Martha's Vineyard | Too cold | 0.5 h | – | 4°C | 12/30 |
| Boston | Too cold | 0.4 h | – | 3°C | 10/30 |
| Plymouth | Too cold | 0.3 h | – | 3°C | 10/30 |
Other months in Massachusetts
- Jan Too cold
- Feb Too cold
- Mar Too cold
- Apr Too cold
- May Too cold
- Jun Excellent
- Jul Excellent
- Aug Excellent
- Sep Too cold
- Oct Too cold
- Nov Too cold
- Dec Too cold
Best months: June to August. Full Massachusetts guide