Paris has a typical Western European oceanic climate (Köppen: ''Cfb''), which is affected by the North Atlantic Current. The overall climate throughout the year is mild and moderately wet. Summer days are usually warm and pleasant with average temperatures between , and a fair amount of sunshine. Each year, however, there are a few days when the temperature rises above . Longer periods of more intense heat sometimes occur, such as the heat wave of 2003 when temperatures exceeded  for weeks, reached  on some days and rarely cooled down at night. Spring and autumn have, on average, mild days and fresh nights but are changing and unstable. Surprisingly warm or cool weather occurs frequently in both seasons. In winter, sunshine is scarce; days are cool, and nights are cold but generally above freezing with low temperatures around . Light night frosts are however quite common, but the temperature seldom dips below . Snow falls every year, but rarely stays on the ground. The city sometimes sees light snow or flurries with or without accumulation.