Winters in Brookline are cold, with temperatures often below freezing, averaging around -2°C in January and February. Spring brings a gradual warming trend, with temperatures rising steadily through March and April, averaging around 4°C and 9°C respectively. Summer months of June to August see warm temperatures, with highs reaching up to 35°C on occasion, but also experiencing cooler days around 13°C. Autumn sees a return to generally mild temperatures, with September's average temperature being the highest of the season at around 19°C, before gradually cooling down through October and November. The winter months tend to be the coldest, while spring and autumn have more moderate temperatures, with summer being the warmest period overall.