Rotterdam, the Netherlands' great port city, sits in the west of the country on the Nieuwe Maas in the Rhine–Meuse delta, close to the North Sea and largely at or below sea level, at approximately 51.92°N, 4.48°E. It has a temperate oceanic climate (Köppen Cfb) — cool, cloudy, breezy and changeable, moderated by the nearby sea — essentially the same mild, damp maritime climate as the rest of the western Netherlands.

Summer, from June to August, is mild rather than hot, with July and August the warmest months — average highs around 22–23°C and cool nights. Hot days are uncommon, though warm spells can briefly push temperatures into the low 30s. Atlantic and North Sea air keeps the season changeable, with showers possible at any time, but summer is among the sunnier, drier and most agreeable parts of the year, with long daylight hours.

Winter, from December to February, is cold and damp rather than severe, kept mild for the latitude by the surrounding sea, with January and February the coolest — average highs around 7°C and lows near 2°C. Frost is common on clear nights, but hard freezes and lasting snow are relatively uncommon, so the season is more often grey, wet and windy than icy, with short daylight and frequent cloud.

Rotterdam receives around 800–850 mm of precipitation a year, spread through every month with an autumn maximum, usually as light drizzle or brief showers rather than heavy downpours. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Like Amsterdam, Rotterdam's weather is shaped by wind, cloud and the proximity of the sea, with frequent Atlantic depressions bringing changeable conditions year-round. Its position at the low-lying mouth of the Rhine–Meuse delta, much of it below sea level, makes flood defence central to the city — the vast Maeslant storm-surge barrier guards it against the North Sea storms that autumn and winter can drive up the estuary.

To follow any single measurement in Rotterdam more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.