Lake-strewn Finland has a maritime feel, although the huge air masses that build over continental Russia are never too distant. The ebb and flow between these influences is the main driver of Finnish climate. The Atlantic and the high latitude keep things relatively cool in summer, with few big temperature differences across the country. It seldom gets much above 26°C/79°F anywhere in Finland; the warmest ever recorded across Lapland in mid-summer is on a par with that in Helsinki. Showers and some thundery spells dampen the landscape every two or three days, with plenty of sunshine otherwise. It doesn't take long for autumn to feel wintry, especially across the north. By January, Siberian cold usually muscles out Atlantic air, freezing over the Gulfs of Bothnia and Finland. Even the southwest Finnish coast – the closest approach to open water in mid-winter – is nearly as frigid as Moscow on average. There's at least a dab of snow (usually light) on most days, and temperatures struggle to get above freezing. As you move north, the cold is more entrenched and the snowfall a bit lighter, but the snowpack itself is deeper due to less thawing and a longer snow season. Lapland gets the worst of it, although most of Finland has dipped below –30°C/–22°F at least once. The biting cold spells of winter become crisp and sunny during spring, Finland's driest period. The snow melts from south to north and inland during April and May, and temperatures become comfortable enough to enjoy the sunshine without a heavy jacket. Finland experiences a bit more fog than neighbouring countries: up to eight days a month at some coastal cities and towns, with the lowest likelihood in spring.