Bautzen has a continental climate — warm summers with daytime highs in the low to mid 20s C, cold winters that regularly drop below freezing. May through September are the most reliable months for walking around the old town and visiting the riverside.
The two festival highlights are the Easter weekend, when Sorbian villages around Bautzen hold the famous Osterreiten — processions of men on horseback, dressed in formal black coats, riding through the parishes. December brings the Wenzelsmarkt, one of the oldest Christmas markets in Germany, running since 1384. Both are worth timing a visit around.