Menorca's peak season is June through September, when the island's beaches fill with European tourists and accommodation prices are at their highest. July and August are the busiest months; August in particular sees the island operating at full capacity. The south coast beaches are justifiably famous and worth the crowds, but book everything well in advance.
May, June, and September are the best times to visit: the sea is warm enough for swimming, the island is green from winter rains, and the crowds are manageable. October is quiet and still mild — good for walking and cycling, though some smaller restaurants and boat services close. November through April is off-season: many tourist facilities close, but the island has a genuine local life and the prehistoric monuments and walking routes are uncrowded.
The Tramontana wind, blowing from the north, affects the north coast year-round and makes some north-facing beaches uncomfortable. The south coast is more sheltered and warmer. The island receives less rain than mainland Spain but more than the western Balearics; spring brings wildflowers to the rural interior.