Rotterdam enjoys a fairly steady, temperate climate all year. You’ll not need a dip in the pool to keep cool in the summer, and heavy coats and boots are hardly necessary in winter.
Average temperatures in Rotterdam in June range from about 60 to 65 degrees Fahrenheit, with lows in the mid 50s. But Rotterdam weather can be unpredictable. One summer day it might be 90 and the next, 75. Packing for a trip here means packing clothes that can be layered. July can be a rainy month in Rotterdam, with rainfall averaging 2 inches each July ever year.
Overall, rainfall is fairly steady all year in Rotterdam, with no month particularly more wet than any other. Each month, rainfall ranges from 1.5 inches to 2.5 inches, so be sure to bring an umbrella and perhaps a light rain jacket.
If you’re headed to Rotterdam in the winter, expect temperatures around 40 in December and 38 in January. At night, it will be in the mid 30s.
Thanks to the fairly temperate climate in Rotterdam, there is no one best time of year to visit the city, but if you must choose, choose summer, when there are a variety of activities to choose from and the potential for warm weather.