Block Island weather by month & the best time to visit
United States · seaside town · humid subtropical climate
The best time to visit Block Island is July — its sunniest month (Sunshine Score 75/100), with August and September close behind. Block Island averages about 2,278 hours of sunshine a year. Daytime highs around 23°C / 73°F and roughly 91 mm of rain in July.
When is the best time to visit Block Island?
For sunshine, the best time to visit Block Island is July, then August and September. The dullest month is January (0/100, 98 mm of rain). The full month-by-month picture is in the table below.
How sunny is Block Island?
Block Island gets a moderate 2,278 hours of sunshine a year. 75 Sunshine Score points separate July (75) from January (0), so the month you pick matters. It ranks #291 of 580 destinations in United States for annual sunshine, below the national median of 2,279 hours. The year's 1,255 mm of rain spreads fairly evenly across the months, with no pronounced dry season.
Sunshine Score by month
| Month | Score | Day high | Night low | Rain | UV | Sea |
|---|---|---|---|---|---|---|
| January | 0 | 4° / 39°F | 0° / 32°F | 98 mm | 1 | 7° / 45°F |
| February | 0 | 4° / 39°F | -1° / 30°F | 95 mm | 2 | 5° / 41°F |
| March | 0 | 6° / 43°F | 2° / 36°F | 117 mm | 3 | 6° / 43°F |
| April | 6 | 9° / 48°F | 6° / 43°F | 110 mm | 5 | 8° / 46°F |
| May | 38 | 14° / 57°F | 10° / 50°F | 90 mm | 6 | 13° / 55°F |
| June | 67 | 19° / 66°F | 16° / 61°F | 101 mm | 7 | 18° / 64°F |
| July | 75 | 23° / 73°F | 20° / 68°F | 91 mm | 7 | 21° / 70°F |
| August | 75 | 24° / 75°F | 21° / 70°F | 91 mm | 6 | 22° / 72°F |
| September | 74 | 21° / 70°F | 18° / 64°F | 99 mm | 5 | 20° / 68°F |
| October | 52 | 17° / 63°F | 13° / 55°F | 127 mm | 3 | 17° / 63°F |
| November | 24 | 12° / 54°F | 8° / 46°F | 104 mm | 2 | 15° / 59°F |
| December | 0 | 7° / 45°F | 3° / 37°F | 132 mm | 1 | 9° / 48°F |
Sea temperature in Block Island by month
The sea off Block Island is warmest in August at around 22°C / 72°F, and coolest in February at 5°C / 41°F. The water sits at a comfortable 21°C or warmer roughly 2 months a year. Month-by-month sea-surface temperatures are in the Sea column of the table above.
Nearest destinations
Block Island: questions and answers
What kind of destination is Block Island?
Block Island is a seaside town in United States with a humid subtropical climate — the sea reaches 22°C at its warmest and is swimmable (21°C+) about 2 months a year.
How many hours of sunshine does Block Island get a year?
Block Island gets about 2,278 hours of sunshine a year, at its best around July.
When is the best time to visit Block Island?
The sunniest time to visit Block Island is July, when the Sunshine Score peaks at 75/100 (with August and September close behind). Expect daytime highs around 23°C / 73°F.
What is the least sunny month in Block Island?
January is the least sunny month in Block Island, scoring 0/100 with about 98 mm of rain.
What is the sea temperature in Block Island?
The sea in Block Island ranges from about 5°C (February) to 22°C (August). Month-by-month sea temperatures are on this page.
How strong is the sun in Block Island?
The typical midday UV index in Block Island peaks around 7 (high) in June, easing to about 1 (low) in January. Month-by-month midday UV values are in the UV column of the table on this page.
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