Los Cabos is hot in the summer. From June through September, most days are in the 90's, sometimes topping 110 degrees inland, but seldom over 100 near the ocean. Ocean water temperatures can rise above 90 degrees. Nights are increasingly warm and humid as August approaches. Humidity hangs in the 70's.
Autumn brings abrupt change.
Weather remains warm and muggy until the ocean currents begin to cool in mid-October. October is the major transition month, as the trade winds reverse direction and weather patterns shift. Nights are cool again, and people stop sweating. The change can be remarkably sudden, but is always welcome. Although infrequent, rain is more likely in the autumn than in the spring.