The study looked at how rainfall changes throughout the day in Sumatra. They used data from rain gauges at 186 stations to see how much rain falls, how often it rains, and how hard it rains. They found that areas with more rain also have more rainy days. Rainfall peaks in the afternoon and early evening, especially in mountainous areas. Rain events that last longer tend to peak later in the day. The amount of rain also depends on the wind and clouds moving over the land and sea.