The climate of Saint John is humid continental (Köppen climate classification Dfb). The Bay of Fundy never fully freezes, thus moderating the winter temperatures compared with inland locations. Even so, with the prevailing wind blowing from the west (from land to sea), the average January temperature is about −8.2 °C (17.2 °F). Summers are cool to moderately warm, and daytime temperatures usually do not exceed 25 °C (77 °F). Saint John experiences a considerable amount of fog during the summer months, though the fog usually does not last throughout the entire day.
Annual precipitation in Saint John totals about 1,390 millimetres (55 in) annually and is well distributed throughout the year, although the late autumn and early winter is typically the wettest time of year. Snowfalls can often be heavy, but rain is as common as snow in winter, and it is not unusual for the ground to be snow-free even in mid-winter
