Riga has a moderate climate, influenced by its close proximity to the sea. Summers tend to be short and cool with cloud cover, and high temperatures average around 64°F (18°C). Winters are usually long, dark and cold, with temperatures averaging between 18°F (-8°C) and 28°F (-2°C) in January. Snowfall is heavy and snow cover usually lasts from mid-December to mid-March. The city is overcast for roughly 40 percent of the year.