In alt.global-warming on Wed, 22 Aug 2007, "
wrote :

In a country as large as the US, there's likely to be records set
*somewhere* every day - especially where the station has a short record.

The number of records broken should be roughly inversely
proportional to the logarithm of the number years involved.

That's what I expected, although I didn't know the nature of the
function involved.

I became
aware of that when I started attending a new high school, many years
ago. The first year there was naturally a new school record
established in every event. Assuming a random distribution of
student abilities, the second year, there would be a roughly 50%
chance of any prior record being broken, the third year there would
be a roughly 1 in 3 chance of a prior record being broken, and now
that my former high school is about 40 years old, there'd be a
roughly 1 in 40 chance of a record being broken

Or would be, if all conditions remained equal - but IRL training,
equipment & facilities improve, thus throwing a spanner in the works.

In a similar vein, with temperatures rising on the average, record
highs should be somewhat more common than the logarithmic rule, record
lows should be somewhat less common.

That does seem to be the trend.
--
Paul Hyett, Cheltenham