By noon, only 20 percent of planes scheduled to depart Arlanda Airport had taken off, The Local.se reported, and only 13 of 100 scheduled arrivals had landed. Officials said about 60,000 passengers were delayed.
"It's been a lost day for travel in Sweden," Klas Nilsson, a spokesman for Swedavia, which operates the airport 23 miles north of Stockholm, told the TT news agency.
Posten, the Swedish postal service, said mail service was suspended in parts of the Stockholm area and some other regions.
Inter-city trains were delayed by as much as an hour, the rail company SJ reported. Trams and trains around Stockholm were also running late, while bus service was suspended at about 3 p.m.
Thousands of people in central Sweden lost electrical power.
Police advised drivers to stay off the roads.
"The roads are in rough shape right now. If you don't need to go out, try to avoid doing so for the moment," Police Officer Lars-Goran Nilseryd in Ostergotland County south of Stockholm told TT.