31st July is the eve of Lammas, the first festival of the British harvest season, as the year turns from high summer towards harvest. Lammas Eve is also the birthday of William Shakespeare's Juliet:
Even or odd, of all days in the year,
Come Lammas Eve at night shall she be fourteen.
The word Lammas comes from the Old English word "hlafmaesse" or "loaf mass". It's the festival of bread - maybe a day for blessing the loaves made with the first wheat of the harvest.
A combination of a celebration of the beginning of the harvest and plentiful food, and the use of the loaf in the Catholic Mass, in the act of transubstantiation.
Today, Lammas heralds the beginning of August, high summer but with a hint of autumn and fruits and berries on the bushes and trees.