Record Highest Temperatures by State. Some of the all-time records are surprisingly old
Source: National Climatic Data Center
Discussion
The only reason why they aren’t older was because they weren’t really recorded in detail.
Yes thats also concenient. Many new records are set in areas where they didnt measure before. But the US is a good benchmark.
The last temperature peak was in the 40s as this dataset and US temp data pre-1999 confirm.