Yes 1991-2020. It's updated every 10 years. A 30 yr average updated every 10 years with a good database prior to 1991 should have a good sample size in it to capture things on smaller time scales and also some larger time scale features too. For instance we had a hell of a snowy period from the 00s to 2018 or so. But we know in reality, that our long term avg certainly is not supportive of those values during that time.
We talk about temps all the time especially over the last few winters. There is nothing more frustrating then to finally have winter temps but either the moisture lacks or the tracks precisely eff you just enough to suck the joy out of anything wintry. That’s how it’s felt since early December.
It’s akin to the weenies saying back is broken in August when we get our first cool shot. It’s definitely going to get colder after 3/1 but maybe it last 7-10 days? You can see the PAC jet seems like it wants to get more active. That cold won’t last long by that date if it happens.
But you can already see it may be breaking down by the end there. I dunno, back is broken after this weekend imo. Doesn’t mean it can’t have some snow or cold, just like in August when we can have heat and dews.