Visiting local bars in Tainan is better in good weather. These rainfall averages and temperatures can help you determine the best time for bar hopping. The hottest months are usually July and August with an average temp of 83°F, while the coldest months are January and February with an average of 68°F. The rainiest months in Tainan are August, June, May, and July, with each month seeing an average of 16 inches of rainfall.