If you're hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Huai'an: The hottest months are usually July and June, with an average temperature of 25°C, while the coldest months are January and December, with an average of 5°C. The rainiest months in Huai'an are July, August, June and September, with each month seeing an average of 183 mm of rainfall.