Amersfoort's winters are chilly and unpredictable, with temperatures often below freezing in January and December, but occasionally rising into the mid-teens. Spring arrives slowly, with March and April featuring mild temperatures around 10-12°C, but also some colder days. Summer is warm and relatively stable, with June to August averaging high teens to low twenties, although occasional heatwaves can push temperatures above 30°C. Autumn brings a return to cooler temperatures, with September and October experiencing some frosty mornings, while November's weather is generally mild.