Weather in Bar Harbor in May

Shoulder season. May sits in between. You will get good days and you will lose some. Highs sit at 14.1 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

May ranks 5 of 12 in Bar Harbor: past the worst of the year but short of August, which is the month to book if the dates are open.

Rain on 13 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 14.1 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest May day reached 25.9 °C and the coldest night fell to 0.3 °C, and the wettest single day dropped 51 mm — roughly 53% of the month's rain in one day.

May is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest May on record still delivered 193 mm against 34 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 96 mm average is a reasonable planning figure, not a promise.

Wind is light at 5.2 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 84%, which at 14.1 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How May sits in the year

The month is on the way up: 5.3 °C warmer than April, and June adds another 4.4 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in May

14.8 hours of daylight, gaining 1.1 hours across the month. That is between Bar Harbor's extremes of 15.5 and 8.9 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 6.9 °C in May — too cold to swim without a wetsuit. The sea peaks at 15.1 °C in August and bottoms out at 3.8 °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

Shoulder. The value months — prices ease off and you get the place closer to itself.

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

May in Bar Harbor versus nearby

If Bar Harbor is one option among several, the nearby comparison is worth making. Sherbrooke is close enough to be a coin toss — 3.3 °C warmer, 4 days more rain. Boston is a better bet in May — 5 °C warmer, 1 day less rain.

So: May is a compromise. August is 22 points better and is what Bar Harbor is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Bar Harbor

See all twelve months in Bar Harbor, or where else to go in May.