Record temperatures and random chance

This is something I have been thinking about for a while but has been brought to a head by this article: Extreme weather in 2019 broke over 120,000 records in US: report.

Extreme weather incidents in 2019 set more than 120,000 daily records across the U.S. according to data from the National Centers for Environmental Information.

The 122,055 records set include record daily high and low temperatures as well as record rain and snow.

CNN reported on the record events, noting heat waves that hit Alaska and raised temps to 90 degrees Fahrenheit, a winter storm that brought snow to Hawaii, and rain that flooded the Midwest and hurt crops.

The report comes after a year of devastating climate events, from Hurricane Dorian to record melting of ice sheets. Other countries also saw record-breaking heat and cold, and raging fires severely damaged the Amazon rainforest.

Note that these records are not just about heat, as in global warming, but about cold, and rain and other climate events that ended up breaking whatever had been the previous record. My quesion therefore is this, and I will stick to just record high temperatures.

If there are 365 days in a year, and a weather station has been in existence somewhere for say 120 years, how many days during any normal year will turn out to produce a record high temperature just by random chance?

As far as I can tell, there should be approximately three such record temperatures a year for each and every weather station. And if the station has only been running for 60 years say, then there should be around six days during the year that should produce a record high temperature. A new station should have 365 records a year and after a year 183.

This looks obvious to me. So is this right or wrong, and if it’s wrong, why is it wrong?

And of course, if it is right, then these weather cranks should shut up every time some record is broken somewhere since a new record is in itself meaningless.

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