Wisconsin Weather


Climate is a hot topic.

It's important to look at the facts and raw observations.

The attached graph is contains raw weather observations from Green Bay, WI. The Green Bay record book goes back to 1886 and is 99% complete (i:e little/no missing data). The observation site isn't surrounded by concrete, airplanes, or escalating urbanization and has been relatively undisturbed in it's history (a couple relocation's long ago).

In this one graph we are able to see this year, last year, five year, and 30 yr trends. Also able to see 1, 3, 6,and 12 mo trends against the 30yr average. This graph tells the story of where we are and where we've been. We can speculate where we might be going.

Here are some observations:

  • -7.7° below avg over the last 30 days (1mo). - Most of that driven from cold weather from mid-October to present. Maybe the strongest negative deviation from 30yr I've seen, though last Jan/Feb would be close.

  • Spikes above and below 2 standard deviations - 2 standard deviations is like the ZONE of normal weather variation. Normal in Wisconsin is a back forth across the AVERAGE. Very rarely do we see average weather. In the last 3 months we've pushed outside of that zone of normal, seeing record warm(mid Sep) and record cold (Nov). Extremes often come with sun solar minimum and low sunspot count. So this makes sense

  • Pretty much the same thing last year - Actually the trend from late Oct to now is pretty much the same last year vs. this year. Even colder this year. Make's me wonder if a warm December is ahead of us? Last December you got the feeling things would turn for the worse. Perhaps Dec is similar this year, will we get pummeled again in Jan/Feb/Mar?

Green Bay, WI Climate graph last updated on Thursday, Nov 14 2019.
Green Bay, WI Climate graph last updated on Thursday, Nov 14 2019.
  • Long winter - Not because every month will be really cold. Last winter December was very mild, warm, and quiet. It's a long winter because above average in winter is 30's and 40's. When you bookend it with record cold (winter-like) November and March, winter becomes almost 6-7 months long (longer in northern areas)! Last year Mother nature flipped the switch after Jan 1. If you took the Dec-Feb timeframe; it would be below average. But that doesn't tell the full story either.

  • Last Mar/Apr wasn't that cold actually - and maybe if you looked at observation sites further north and west it would've been. A deep snow cover across the state limited heat transfer into the state. Without the snow it would've probably been above average. 75% of the time cold November leads to cold March. So odds are we follow a similar path this year

  • -1.6° vs. 30yr average last 12 mo - That means our climate is colder right now. I prefer to call it a period of extremes with more cold shots than warm shots. It seem's when the sun is weak, the cold wins. You can see this in the 5yr average line too...winter much colder at times.

That's what I've got on my mind today. Thanks for reading! Feel free to leave questions or comments below.

We use Green Bay, WI because of it's lengthy and undisturbed history. All of our historical data is located here for you to perform your own analysis.

This graph is updated daily here - > https://wisconsinwx.com/MAPS/graphs/climate/greenBayWI.jpeg



Write comment here...
Add Media

Recent Stories

Sign in or register to join the conversation!