The climate of Koblenz is classified as warm and temperate. Weather can be cool at times, but will not be freezing even during the peak winter times. There is no specific rainy season and so, you can expect showers any moment.
Summer (June – August): The summers are warm and the temperatures vary from 20 to 24 degree Celsius on a maximum and 11 to 14 degree Celsius on a minimum. This is the peak season to visit Koblenz.
Winter (December – February): Winters are mild and slightly cold. The maximum temperature is around 4°C to 5°C while the minimum is -1°C to 1°C on an average. This is basically off-season for tourists in Koblenz.
Spring (March – May): Spring sees a temperature between 10°C-19°C max and 2°C-9°C min. This is also a good season to visit Koblenz.
Autumn (September – November): Like spring, even autumn has large variations in the temperature. They average high and lows range around 8°C-10°C and 2°C-11°C respectively.
Koblenz is on the trip planners of vacationers all year long. However, the best time to visit the city is during the summer months (June through August) when the Rhine-Valley is at its best.