The heat in many parts of the country this summer has been impressive for sure. One of the recent heat waves there were approximately 3000 record highs broken. That is certainly a large number, but that is just a small percentage of the nearly 400,000 records in the database for cities in the United States and many events in the past recorded even more and with fewer recording sites.
Plus, many of those records were from locations whose database only goes back to post World War II, meaning, the extreme heat waves from the 1930s and others ones from the 1910s and 1920s were not included. In Fargo Moorhead, for example, only one record (and the tie from last Friday), has been set in July since the drought and hot summers of the 1980s. In addition, almost all the records for this month were set in the 1930s or earlier.
Take away the data before 1950 and many local records may have been broken recently as well, yet, similar to this summer in other areas, that should not be taken then to mean it was the “hottest ever”.