High Season (Jun-Aug)
Everything is open.
The odds of balmy weather to enjoy a cafe or a countryside bike ride are best – but not assured.
Crowds fill the famous museums.
Prices peak, book ahead.
Shoulder Season (Apr & May, Sep & Oct)
Most sights open.
Few crowds.
Prices moderate, only book popular places in Amsterdam
Weather mixes the good with wet and cold. Bring warm clothes to enjoy outdoor cafes.
Low Season (Nov-Mar)
Many sights outside of major cities closed.
It may just be you and a masterpiece at a famous museum.
Weather cold and or wet, biking is only for the hardy.
Deals abound.
Read more: http://www.lonelyplanet.com/the-netherlands/weather#ixzz3pCwxl4IZ