Weather in Rotterdam in May

A good month. May is a solid month to be in Rotterdam. Highs average 15.8 °C, lows 9.2 °C, and rain falls on 12 days — nothing in the month is working against you.

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

Rain on 12 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 15.8 °C days and 9.2 °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 May day reached 25.6 °C and the coldest night fell to 3.5 °C.

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 101 mm against 14 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 56 mm average is a reasonable planning figure, not a promise.

Wind is light at 13.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 80%, high enough to notice on the warm days without dominating them.

How May sits in the year

The month is on the way up: 3.2 °C warmer than April, and June adds another 3.1 °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

15.6 hours of daylight, gaining 1.5 hours across the month. That is between Rotterdam's extremes of 16.7 and 7.8 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 10.6 °C in May — too cold to swim without a wetsuit. The sea peaks at 17.7 °C in August and bottoms out at 6.4 °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.

May in Rotterdam versus nearby

If Rotterdam is one option among several, the nearby comparison is worth making. Breda is close enough to be a coin toss — 2.6 °C warmer, 1 day more rain. Lille is a better bet in May — 2.6 °C warmer, 1 day less rain.

So: May works, with June the better month by 10 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Rotterdam

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