This comment shows up on every thread on this topic. Have a look at this data another user posted: http://ocean.dmi.dk/arctic/meant80n.uk.php

The last three years have been highly above average in the arctic. This isn't "arctic has one warm day!". It's "the entire year is abnormally warm in the arctic, like the past three!"

The appropriate comparison would be the US having a whole winter which is 10-20 degrees colder than normal.