Islip weather by month & the best time to visit
United States · seaside town · humid subtropical climate
The best time to visit Islip is July — its sunniest month (Sunshine Score 75/100), with September and August close behind. Islip averages about 2,252 hours of sunshine a year. Daytime highs around 27°C / 81°F and roughly 95 mm of rain in July.
When is the best time to visit Islip?
For sunshine, the best time to visit Islip is July, then September and August. The dullest month is January (0/100, 81 mm of rain). The full month-by-month picture is in the table below.
How sunny is Islip?
Islip gets a moderate 2,252 hours of sunshine a year. 75 Sunshine Score points separate July (75) from January (0), so the month you pick matters. It ranks #302 of 580 destinations in United States for annual sunshine, below the national median of 2,279 hours. The year's 1,206 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 | 3° / 37°F | -3° / 27°F | 81 mm | 1 | 5° / 41°F |
| February | 0 | 3° / 37°F | -3° / 27°F | 85 mm | 2 | 4° / 39°F |
| March | 0 | 6° / 43°F | 0° / 32°F | 105 mm | 3 | 6° / 43°F |
| April | 24 | 12° / 54°F | 5° / 41°F | 106 mm | 5 | 9° / 48°F |
| May | 56 | 17° / 63°F | 11° / 52°F | 94 mm | 6 | 14° / 57°F |
| June | 72 | 23° / 73°F | 16° / 61°F | 110 mm | 7 | 19° / 66°F |
| July | 75 | 27° / 81°F | 20° / 68°F | 95 mm | 7 | 23° / 73°F |
| August | 73 | 27° / 81°F | 20° / 68°F | 103 mm | 7 | 23° / 73°F |
| September | 74 | 24° / 75°F | 17° / 63°F | 99 mm | 5 | 23° / 73°F |
| October | 52 | 17° / 63°F | 11° / 52°F | 120 mm | 3 | 18° / 64°F |
| November | 25 | 12° / 54°F | 6° / 43°F | 90 mm | 2 | 14° / 57°F |
| December | 0 | 6° / 43°F | 1° / 34°F | 118 mm | 1 | 8° / 46°F |
Sea temperature in Islip by month
The sea off Islip is warmest in July at around 23°C / 73°F, and coolest in February at 4°C / 39°F. The water sits at a comfortable 21°C or warmer roughly 3 months a year. Month-by-month sea-surface temperatures are in the Sea column of the table above.
Nearest destinations
Head-to-head
How Islip compares month by month: Islip vs New York · Islip vs New Haven · Islip vs White Plains · all comparisons
Islip: questions and answers
What kind of destination is Islip?
Islip is a seaside town in United States with a humid subtropical climate — the sea reaches 23°C at its warmest and is swimmable (21°C+) about 3 months a year.
How many hours of sunshine does Islip get a year?
Islip gets about 2,252 hours of sunshine a year, at its best around July.
When is the best time to visit Islip?
The sunniest time to visit Islip is July, when the Sunshine Score peaks at 75/100 (with September and August close behind). Expect daytime highs around 27°C / 81°F.
What is the least sunny month in Islip?
January is the least sunny month in Islip, scoring 0/100 with about 81 mm of rain.
What is the sea temperature in Islip?
The sea in Islip ranges from about 4°C (February) to 23°C (July). Month-by-month sea temperatures are on this page.
How strong is the sun in Islip?
The typical midday UV index in Islip 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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