[Wuli]

I find the format of the data list is confusing.
For what date (CCYY) is the RH data and for what date (CCYY) is the NH data???

Is the format attempting to say the RH date is for the ONLY date (CCYY) date shown next to it, and the NH data is for when????

[CedarDave]

For example, for the date of November 23rd, the Record High was 74 in 1909. The Normal High for that date is 52.

Normal highs are determined on a 30-year moving average for the shown date, presently from 1981-2010. Thus 30-year averages for November 23 from 1961 to 1990 and 1971-2000 may be (and likely are) different from the current "normal" high for that date.

https://w2.weather.gov/climate/help/glossary.php