Earlier quoted context omitted.
How exactly do they do a fair comparison between 1880 and today? I'm assuming the temperature readings today are very accurate, but how accurate were the measuring devices going back in history, and their standards for taking temperature? Most of the thermometers I have in my house are +- 2F, which would eliminate the differences entirely.
There are significant temperature records that go back much farther than 1880 even. Many navies and armies kept records from all over the world, so we actually have lots more data than people think. There are also bodies of science that deal with 'aftcasting', which is making a weather forecast for a date in the past. These techniques have been refined to the point where we can make 1-day aftcasts for ~1850 that are…
Seriously, our forecasts are nearly always wrong. So.....saying we can make as accurate of forecasts for 200 years ago...that's not really saying much.
This is after moving to two cities in the same state, more than 100 miles apart, the forecasts still never get better.