I genuinely cannot tell if this is ill-intent or an internal struggle to revisit your previously held opinions when faced with the body of evidence of all the data collected after the industrial revolution.

You introduce bias by your selection of measurements. Plus a large portion of the earth is scantly inhabited with no weather stations in place. Like the poles or international waters.

Instead you should look at satellite measurements of the temperature across the entire planet. These are widely available. The scientific discourse and the available evidence is much more advanced than "hey it became colder in those 20 places".

https://en.wikipedia.org/wiki/Satellite_temperature_measurem...

For the Miami case, it is probably worth noting that Miami is cooler during El Nino events and warmer during La Nina. Of course, 2000 was in the middle of the latter and 2020 the former. In fact, if you look at more than 2 datapoints the trend over the past twenty years is the opposite of what you're saying.

Now try doing that systematically. Take the monthly averages over 20 years from a few thousand sites. Don't forget to correct for the urban heat-island effect, which creates a false impression of warming when a city grows out around an airport.

Do that, present your results, and it might be worth taking you seriously.

Picking 2 dates at random is not a good way to expose long-term trends, as evidenced by your observation that there can be several degrees of variation from one year to the next.