This one took a bit longer than 15 minutes because I had to appropriate the data from a PDF publicly available from weather.gov
I had to first extract the data, then massage it a bit and, finally, import it into Excel.
The graph on this page shows the average yearly temperature along with a 7-year moving average to get an idea of how the temperature change looks over time (in other words, is it going up?)
No, and since this was a one-off project just for my own curiosity, I didn’t even look for that info. Thanks, though. I am sure someone in this forum needs that!