If you're looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Nong Khai: The hottest months are usually April and March, with an average temperature of 29°C, while the coldest months are January and December, with an average of 24°C. The rainiest months in Nong Khai are August, July, September and June, with each month seeing an average of 371 mm of rainfall.