Winters in L'Hay-les-Roses are cold and variable, with temperatures often below freezing but occasionally rising into the mid-teens. As spring approaches, temperatures gradually warm up, with April and May being particularly mild, with average highs reaching as high as 25°C. Summers are warm but not hot, with July and August averaging around 19°C, while September brings a slight cooling trend. Autumn is cool and unpredictable, with October experiencing some chilly days, but November and December temperatures can be quite similar to those in January, suggesting a relatively mild winter overall.