I live an hour drive north-east of Bruges and it should be freezing now this time of the year, but temperatures are still here above zero. Average temperatures here in the coastal area between 10 and 15 ºC in May and usually it rains often, but will this be the case this year? Also wind can be a challenge in this flat coastal area, but everything will be in full blossom and with sunshine it’s good weather for cycling.
The following I can recommend is the canal and country-side north-east of Bruges to Damme and Oostkerke, a popular place for cycling. You can go further (along the canal) north to little town Sluis and St Anna ter Muiden just across the border in The Netherlands. Countryside north of Sluis is also lovely, a lot of dykes and old reclaimed land from the sea. Best time is during the week when everything is quiet and the atmosphere is at it’s best.
Some 10km north of Bruges the huge 13th century tithe barn and Lissewege is worth a cycling trip.
South of Bruges you can do the 47km long castle route, however most castles are in 19th century neogothic “romantic” style, but nevertheless lovely.
More routes in Belgium on: www.fietsroute.org with info also in English.