Other facts from our historical weather data: Which months have the greatest rainfall in Arecibo? Most rainfall (rainy season) is seen in May and September. Which is the hottest month in Arecibo? August has an average maximum temperature of 31°C (88°F) and is the hottest month of the year. Which is the coolest month in Arecibo? The coolest month is March with an average maximum temperature of 28°C (82°F). Which is the wettest month in Arecibo? May tops the wettest month list with 172mm (6.8 in) of rainfall. Which is the driest month in Arecibo? February is the driest month with 49mm (1.9 in) of precipitation. No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.