The best time to visit Frankfurt is from May to September. The warmer months of June, July, and August are ideal for a city trip, especially for exploring the surrounding area with your camper van or Class C RV rental. Whit Sunday (Pentecost) is a popular time as their traditional folk festival takes place in the Frankfurt city forest on the Tuesday after Whit Sunday. Other highlights include the Mainfest festival which takes place in early August and is a great time to explore Frankfurt’s gardens along the banks of the Main River. For art, culture, and music fans, visit the city in August for the Annual Museum Festival.