Sweden has a mostly cool temperate climate, but the southern quarter of the country is warmer. Norway's mountains act as a rain break, so yearly rainfall is moderate.
Swedish summers are generally fairly sunny with only occasional rainfall, but August can be wet. The average maximum temperature for July is 20°C in the south and around 17°C in the north. Long hot periods in summer aren't unusual, with temperatures soaring to over 30°C.
The harsh Lappland winter starts in October and ends in April, and temperatures can plummet as low as -50°C. Snow can accumulate to depths of several metres in the north, making for superb skiing, but snow depths in the south average only 20cm to 40cm. It usually rains in winter in the far south (Skåne).
The west coast is warmer than the east, thanks to the warming waters of the Gulf Stream.
When to go
Despite its northern location in Europe, Sweden isn't as cold as you might expect. The south has a year-round temperate climate and summer can be quite warm in the north. Sweden is at its best during summer and autumn (late May to September), but hikers and campers may wish to avoid the peak of the mosquito season (June and July).
Due to the country's high latitude, daylight hours are long in summer. Malmö gets 17½ hours of daylight at midsummer, and Sundsvall has constant light during the second half of June, but you have to travel north of the Arctic Circle to experience the true 'midnight sun' - in Kiruna, the sun remains above the horizon for 45 days, from 31 May to 14 July.
Swedes are big on holidays, and even Stockholm shuts down for two or three days around Christmas and midsummer, so plan accordingly. Most Swedes take their vacations from late June to mid-August, so hostels are crowded, but this is also when most hotels offer discounts of up to 50%.
Travel in winter is somewhat restricted and requires some planning as well as serious winter clothing, but there are good opportunities for activities like skiing, dogsledding and snowmobiling. The big cities are in full swing all year, but the smaller towns almost go into hibernation when the temperatures begin to drop (the notable exceptions being popular ski resort towns like Åre, and Jukkasjärvi, home to the Ice Hotel).