Weather in Boston in July

A good month. July is a solid month to be in Boston. Highs average 28 °C, lows 17.7 °C, and rain falls on 12 days — nothing in the month is working against you.

July ranks 5 of 12 in Boston: past the worst of the year but short of September, which is the month to book if the dates are open.

Rain on 12 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: 9 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest July day reached 36.7 °C and the coldest night fell to 10.5 °C, and the wettest single day dropped 49 mm — roughly 52% of the month's rain in one day.

July is moderately variable: 45 mm in the driest year against 220 mm in the wettest, around an average of 94 mm. Roughly two Julys in three land near that average, and the third does something else entirely.

Wind is light at 1.3 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 75%, high enough to notice on the warm days without dominating them.

How July sits in the year

Temperatures hold steady either side: 23.9 °C in June, 28 here, 28 in August. Nothing about the timing within the month matters much.

Daylight in July

July is at or near the longest days of Boston's year: 15 hours of daylight, losing 0.7 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.

Sea temperature

The sea sits at about 18.6 °C in July — swimmable, but it takes a moment to commit. This is the warmest the water gets all year.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

July in Boston versus nearby

If Boston is one option among several, the nearby comparison is worth making. New York City is close enough to be a coin toss — within a degree on temperature, 1 day more rain. Bar Harbor is close enough to be a coin toss — 5.9 °C cooler, 1 day more rain.

So: July works, with September the better month by 9 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Boston

See all twelve months in Boston, or where else to go in July.