May to September is the mildest period, with average highs from 17.6 degrees in May to 22.7 in August. Bruges has about 10 rain days a month through the summer, and 12 to 15 from October to January. Winter days stay around 7 degrees and the shorter museum hours make the day shorter.
Highs go from about 11 degrees in March to 18 in May, with 9 to 10 rain days a month. The Belfry and the Groeningemuseum switch to summer hours on 1 April.
What to wear: Bring layers and a light rain jacket.
Summer
13 to 22 °C · about 10 rainy days a month
Afternoons reach 20 to 23 degrees from June to August and nights stay around 12 to 14. The Belfry is open from 09:00 to 20:00 every day.
What to wear: Wear light clothes and comfortable shoes for cobbles, and carry a light rain jacket.
Autumn
8 to 15 °C · about 12 rainy days a month
September is still mild at about 20 degrees, October about 15 and November about 10. Rain days rise from 10 in September to 14 in November, and the summer hours end on 2 November.
What to wear: Bring a warm layer and waterproof shoes.
Winter
2 to 7 °C · about 13 rainy days a month
Days are about 7 to 8 degrees and nights near 1 to 2 degrees, with 11 to 15 rain days a month. The Belfry opens at 10:00 on weekdays and most museums close at 17:00.
What to wear: Wear a warm coat, a hat and waterproof shoes.
If it rains
Rain falls on about 10 days a month in summer and more in autumn and winter, so keep an umbrella. The Church of Our Lady, the Groeningemuseum, the Sint-Janshospitaal, the Gruuthusemuseum, the Stadhuis, Choco-Story, the brewery and the basilica are all indoors. Keep the Belfry, Minnewater, the Rozenhoedkaai and the Begijnhof for a dry spell.
Even in July and August the average high is only about 22 to 23 degrees, so heat is rarely a problem. On a sunny day carry water and a hat for the Belfry climb and the open squares. Museums and churches give a cool break in the middle of the day.