The British Library Medieval Manuscripts Blog had a post last month about tournaments based upon their archival holdings. It points out that such events were usually held in the summer although ones to celebrate royal weddings or births might be held in winter. At this point the post does have a real howler in confusing King Henry IV and his marriage to Joanna of Navarre, the widowed Duchess of Brittany, with his French namesake of two centuries later. That is possibly explicable, but worrying to see nonetheless from a resource of national importance.
The handsomely illustrated post can be seen at It's tournament season!
In passing I will just add that, for all its improbability and silliness, the film A Knight’s Tale does make some good points about the world of tournaments, likening it to the modern world of motor racing and the glamorous international scene of the thirteenth to the sixteenth centuries in particular.