STATE OF THE CLIMATE: 2023

Here's an example for August 3rd, 2023 of how subtle increases change the probabilities and frequencies of certain temperature extremes. The average high for August 3 has increased 3.5 deg F in the past 63 years.

While not a big increase, it's enough to increase the probability of a 90 degree day on that date from about 15% in 1960 to 23% in 2023. In other words, it's 60% more likely, due to climate change, to hit 90 or higher on August 3.

Here's an example of how an increase in the average impacts cold extremes:

* Winter (Dec-Jan-Feb) average temperatures have increased by about 5 deg F, but the effect on the coldest extreme is exponential: an increase of +12 deg F.

* If we look at the warmest two winters since 2000, about 26.5 deg F average: it has been made 10 times more likely to achieve due to that + 5 deg F of average warming. A winter that would have occurred only once a century on average previously, is now a once a decade scenario...

Again this is an example for River Falls of how probabilities change. In the Twin Cities, reaching -30 or -33 or colder has become an extremely rare (perhaps once in 50 year) probability...

Emerald ash borer mortality with temperature extremes: