Boston's coastal location on the North Atlantic moderates its temperature, but makes the city very prone to Nor'easter weather systems that can produce much snow and rain. The city averages 43.8 inches (1,110 mm) of precipitation a year, with 43.8 inches (111 cm) of snowfall per season. Snowfall increases dramatically as one goes inland away from the city (especially north and west of the city)—away from the moderating influence of the ocean. Most snowfall occurs from December through March, as most years see no measurable snow in April and November, and snow is rare in May and October. There is also high year-to-year variability in snowfall; for instance, the winter of 2011–12 saw only 9.3 in (23.6 cm) of accumulating snow, but the previous winter, the corresponding figure was 81.0 in (2.06 m).[d]