In terms of precipitation, rainfall in Hainan ranges from 20.0 - 270.0 inches per month. September is typically the wettest month, when rainfall can reach 270.0 mm. January is typically the driest time to visit Hainan when rainfall is around 20.0 mm.
If weather is an important factor for your trip to Hainan, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 29.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 18.0 C).