In the Old Testament, events are sometimes dated by the wheat (Genesis 30:14; here) and barley (2 Samuel 21:9; Ruth 1:22) harvests. The wheat harvest took place in May, following the barley harvest. Philistia was grain country, which Samson will now use to his advantage.
1 After some days, at the time of wheat harvest, Samson went to visit his wife with a young goat. And he said, “I will go in to my wife in the chamber.” But her father would not allow him to go in.