The weather in Finland varies widely by season. Summer usually lasts from May to early September, and temperatures can reach up to +35 °C. Autumns are dark and rainy. Winter snow usually begins to fall in Helsinki in early December (in Lapland it can fall as early as October) and in the winter the temperature can drop to -30 °C. Winter usually lasts to mid-March, when the snow melts in Helsinki (in Lapland the snow usually doesn't melt until early May), and Spring lasts till late May. Spring can be erratic, and the weather can change from frost to sunshine within a matter of days. The famed Northern Lights are common in Lapland.