In Sweden it's easier to name the resorts where snow may fall short at Christmas than those where it can be relied on: 26 of 34 are snow-sure, and the median resort over the winters 1984/85–2013/14 saw a snowy Christmas in 28 of 30. 16 resorts have never missed once, even though mid-mountain in the country sits at just 200–900 m. In the north, altitude matters less than in the Alps.
From Jämtland to Dalarna
In Jämtland, Åre at 900 m and Vemdalsskalet at 800 m each recorded 30 snowy Christmases out of 30, as did Riksgränsen in Lapland at 700 m. In Dalarna, Sälen and Idre Fjäll at the same height managed 27 each: that's reliable, only slightly behind the mountain resorts of Jämtland. The weak spots lie elsewhere: Branäs at 400 m scored 14 of 30, Romme Alpin at 300 m just 10, and there the holidays depend on snowmaking. For comparison, Norway has 23 of 29 snow-sure, Finland 8 of 10. What you see here is climate, not a forecast (methodology). For Christmas, you can safely pick Åre or Sälen.