Winters in Barreiro are cool and variable, with temperatures often dropping below freezing in January and February, but also experiencing mild days. As spring approaches, temperatures gradually warm up, reaching pleasant highs by April and May. Summer is warm to hot, with July and August being the warmest months, but even then, overnight lows can be quite cool. Autumn brings a return to milder conditions, with September and October seeing comfortable temperatures before the cooler winter sets in once more.