UV Index
UV Index
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Today's UV index in Boston, United States 
will be up to 5.6, indicating a moderate level of sun exposure for the average person. Check the annual sun radiation in the city and our tips for today to make sure you're safe in the sun.
With a UV index reaching up to 5.6 in Boston, stay shaded during midday when the sun is strongest; wear protective clothing, a wide-brimmed hat, UV-blocking sunglasses; apply SPF 30+ sunscreen every 2 hours, even on cloudy days; and be cautious of heightened UV on bright surfaces.
The UV index in Boston can reach high levels during the summer, with a peak in July. However, the city experiences lower UV index levels in the fall and winter months. On average, Boston has about 205 sunny days per year.
Boston has four distinct seasons: a mild spring, a hot and humid summer, a crisp and colorful fall, and a cold and snowy winter. The city's coastal location helps to moderate temperatures year-round, but can also lead to rainy and foggy conditions.
Compared to its region and neighboring countries, Boston has a milder climate. The city is situated further south than cities such as Montreal and Toronto, and experiences less extreme temperatures than inland areas of the United States and Canada. The Atlantic Ocean also helps to moderate Boston's climate, keeping it milder than inland cities in the same latitude.
The chart below displays the average Shortwave Radiation Sum (MJ/m²) for each month of the last year in Boston. It's designed to provide you with a better understanding of the yearly weather and sun exposure.