Check the weather in Frankfurt in July before you book your next holiday in Germany. Long-term weather average give the best indication of the weather in July 2017 and includes figures for temperature, sunshine and rainfall for Frankfurt, Germany. Weather in Frankfurt in July. The average maximum daytime temperature in Frankfurt in July is a warm 24°C (75°F). There are usually 7 hours of bright sunshine each day, which represents 45% of the 16 hours of daylight. Expect 64mm (2.5 inches) of rainfall across the whole of July with 14 days with some rain falling.