Winters in Bremen are cold and unpredictable, with temperatures fluctuating between freezing and mild days. January is the coldest month, with average highs struggling to reach 2°C. Spring arrives slowly, with March marking a significant warming trend, while April and May bring more consistent warmth. Summers are pleasant but not hot, with July being the warmest month, averaging around 19°C. Autumn brings a return to cooler temperatures, with October often experiencing frosty mornings and mild afternoons.