The climate of Cabo Mexico is known for rains from August to September and the average temperature in Cabo San Lucas peaks at 90 degrees. However, there is only a 20% chance of rain each day. Because it's “rainy season,” this is the best time of year to visit Cabo San Lucas if you want to avoid the crowds. Technically, summer is Los Cabos' rainy season, but most of this destination's scant rainfall comes in August and September.
The annual rainfall in Los Cabos is actually less than seven inches, and most of that amount can fall only during a few storms. Some visitors are surprised by the small amount of rainfall they encounter during the so-called Los Cabos rainy season, but it's important to remember that average rainfall figures can be misleading. A year with a big storm after many years of very dry conditions can skew the numbers to a large extent. That said, April and May tend to be the driest months, and travelers who visit Cabo in spring there is hardly any rain.
At any time of the year, Cabo can go a whole month without precipitation. This is most likely to occur during May and June, the driest months. September, usually the wettest month here, can receive up to two feet (618 mm) of rain. The rainy season is short and light.
August has an average of 2.5 inches of rain and September exceeds three inches. September is the peak month of storm and hurricane activity each year on the Pacific and Atlantic coasts. The average surface water temperature in Cabo San Lucas is rising during June, rising 4° F, from 72° F to 76° F, throughout the month. In Cabo San Lucas, the probability of a rainy day over the course of June increases gradually, starting the month at 1% and ending at 4%.