Weather in Boston in October

A good month. October works. It is not the peak, but nothing about it fights you. Highs average 16.9 °C, lows 7.3 °C, and rain falls on 11 days — nothing in the month is working against you.

October ranks 6 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 11 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 16.9 °C days and 7.3 °C nights; the spread matters more here than any single number.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest October day reached 30.5 °C and the coldest night fell to -5.4 °C, and the wettest single day dropped 91 mm — roughly 74% of the month's rain in one day.

October is moderately variable: 28 mm in the driest year against 331 mm in the wettest, around an average of 123 mm. Roughly two Octobers in three land near that average, and the third does something else entirely.

Wind is light at 2.2 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 79%, high enough to notice on the warm days without dominating them.

How October sits in the year

The month is on the way down: 7.4 °C cooler than September, with November dropping another 6.7 °C. The first week and the last are not the same trip.

Daylight in October

11.1 hours of daylight, losing 1.4 hours across the month. That is between Boston's extremes of 15.3 and 9.1 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 13.9 °C in October — too cold to swim without a wetsuit. The sea peaks at 19.7 °C in August and bottoms out at 4.6 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

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

October 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 less rain. Bar Harbor is the weaker option in October — 3.4 °C cooler, 1 day more rain.

So: October works, with September the better month by 14 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 October.