April to June: Spring - the season for the city’s wonderful Spring Festival - brings milder temperatures of around 10°C to 18°C, though expect plenty of rain, so bring a jacket. You’ll enjoy around 6–7 hours of sunshine a day.
July to August: High season, so expect larger crowds - which mostly head towards the Royal Gardens of Herrenhausen and the Maschsee Lake - and slightly higher accommodation prices. It’s warm and sunny, with temperatures around 22°C to 25°C. You can expect 7–9 hours of sunshine daily and limited rainfall (40–60mm).
September to November: Cooler but still very pleasant weather, with temperatures ranging from 10°C to 20°C. This is the best time to explore Hannover’s many cultural assets, but you can expect the city's museums to be quite busy.
December to March: Winter in Hannover can be cold, with temperatures ranging from -2°C to 6°C. However, the Christmas markets are a real highlight, lending a lovely festive feel to the city. Snowfall is likely, especially in January and February, so pack well.