Other facts from our historical weather data: Which months have the greatest rainfall in Hatillo? Most rainfall (rainy season) is seen in May and September. Which is the hottest month in Hatillo? 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 Hatillo? The coolest month is February with an average maximum temperature of 28°C (82°F). Which is the wettest month in Hatillo? September tops the wettest month list with 167mm (6.6 in) of rainfall. Which is the driest month in Hatillo? February is the driest month with 48mm (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.