In the tropics and sub-tropics, the time of year when typhoons visit, due to the shifts in the direction of the trade winds. In the northern hemisphere, the rainy season starts in August or September, and continues until January or February.
It is also known as typhoon season or monsoon season. When a typhoon comes, it can literally rain for days at a time, sometimes nonstop for an entire week. Rice farmers make sure the harvest is in before the rains come and spoil the crop.
Architecture in the tropics is designed for resisting the effects of these tropical storms, both the heavy rain and the high winds, sometimes over 50-100 kph. Small houses are built of thatch or wood, designed to be easily rebuilt if blown down. (Of course, the family has usually evacuated to safer ground by then).
Most middle-class and upper-class homes are steel-reinforced concrete - protection against both high winds and flooding. Still, flying galvanized iron sheets and timber from somebody's roof is not an uncommon sight during a heavy typhoon.