If Jean de Berry was lounging around the Hôtel de Nesle in Paris, and fancied a spot of falconry, then it would have been an 11 hour walk, according to Google Maps, or probably a 5-6 hour trip on a horse or in a carriage, to get to his Chateau d’Etampes, featured in August in the Tres Riches Heures. This was quite a building for its day, TE Lawrence was a visitor who (on this excellent website) is quoted as calling it “perhaps the most astonishing production of the late twelfth century”. It had all sorts of defensive innovations and was well built, so its central keep is still standing, if a bit worn. It got hammered in the Hundred Years War, as did much of northern France.
I’m not aware that falconry is really a seasonal pursuit. These days in the UK it’s claimed to be a winter sport for reasons that aren’t clear to me, but there’s the Duc de Berry at it in high summer, and its ancestral home is mainly in the decidedly non-seasonal Middle East. More conventionally, there’s a hot sweaty harvest going on in the background, which brings to mind a drowsily persuasive masterpiece by Bruegel in his own series of seasonal paintings, The Corn Harvest
In a way, the Limbourg’s painting gets August right: no-one wants to work too hard, just the essentials, lots of lazing around (see the swimmers), and a general air of self indulgence before the weather begins to turn.