The climate in Sweden is very similar to the climate in North America and Asia which is located in the same northern latitude. However, the winters in Sweden are clearly milder than the corresponding winters of North America and Asia.
SMHI is the largest weather-report agency in Sweden (http://www.smhi.se/vadret), however, SMHI is a bit unreliable, so there are some other sites that we recommend:
If you are in the southern parts of Sweden usually Danish DMI have good eye on the weather.
Are you on the other hand further up in Sweden takes over Norwegian YR over, which have better track.
On Swedish site klart.se can you easily see when the sun goes up and down, and the amount of UV radiation is, how much the moon is illuminated, etc.