Winters in Saint-Sebastien-sur-Loire are cool and variable, with temperatures often dropping below freezing in January and February, but occasionally rising into the mid-teens. As spring approaches, temperatures gradually warm up, reaching averages around 10°C by April and May. Summers are mild to warm, with highs often reaching the mid-twenties to low thirties from June to August. Autumn is generally cooler, with temperatures dropping back down to average lows in October and November, although occasional warmer days can still occur. In winter, the temperature range narrows somewhat, but remains relatively cool overall.