You’d be forgiven for being skeptical of a cold, snowy December. Recent years have often brought late starts to winter. The last colder-than-normal December (using the modern 1991–2020 average, which is much warmer than historical baselines) was in 2022.

Only four of the past 15 Decembers have been colder than normal. Even winters that eventually turned out decent — ending up normal or cold — started warm in December.

December can quite literally set the stage for the winter ahead. It’s a lot easier to be cold and snowy if December starts cold and lays down a good snowpack. This might be that year.

In the layer seven to 31 miles above our heads is the stratosphere, a place we don’t think about much because most of our weather happens in the troposphere, the bottom seven miles of the atm

See Full Page