NOAA and NASA temperature graphs aren’t useful for science, because the data has been altered.

Climate at a Glance | Statewide Time Series | National Centers for Environmental Information (NCEI)

In order to do legitimate science, it is necessary to work with legitimate data.

I ran the Tennessee 365 day mean temperatures though  Fourier Transform and found cyclical behavior at intervals of 3, 4, 5, 9, 11, 18 and 32 years.