May:

The Hague Jazz Festival
26th – 27th May
Not the largest Jazz festival in the country but nonetheless offers a good selection of both Dutch and international artists.

North Sea Regatta
23 May - 5 June
Boat race between Scheveningen and Harwich, England. Onshore, a wide variety of events keep the spectators entertained while they wait at the finishing line.

June:

International Sand Sculpture Festival
June
Artwork in the sand! An incredible array of sculptures rise out of the sandy beaches of Scheveningen.

Parkpop
5 June
Massive free pop concert held in the Zuiderpark.

July:

De Parade
July
Held at the Westbroekpark, ten days of performances, entertainments, games, circus shows and fairground rides.

November:

Crossing Borders Festival
15 - 18 November
One of Europe's largest festivals, combining literary talents, musical talents & visual arts talents in a showcase of over 80 acts staged at The Hague's Theater aan het Spui.