St. Thomas, Canada experiences a continental climate with distinct seasonal variations in temperature. Winter months from January to March are cold, with temperatures often dropping below -10°C and averaging around -5°C. Spring brings gradual warming, with April and May seeing average highs around 13-21°C, while summer is warm but not hot, with July and August averages hovering around 20-22°C. Autumn is mild, with September and October temperatures ranging from 6-25°C, before cooling down in November and December. Overall, the temperature fluctuations are moderate, with no extreme heat or cold periods throughout the year.