Why is the temperature difference so big now?

Mainly due to global warming, the humidity in temperate regions has become unbalanced.

Generally speaking, the temperature difference is mainly affected by the pressure difference and humidity.

For example, in winter in China, Mongolia and Siberia have strong high pressure and strong cold air masses, which directly drive into China, bringing strong cold air, so the weather is cold and the temperature difference is large.

The rainy southern region is humid. Because the specific heat capacity of water is larger than other underlying surfaces, the temperature difference in the humid region is generally smaller.

In addition, vegetation will also affect the temperature difference. In areas with good vegetation coverage, the surface insulation effect is stronger than that of sandy soil without vegetation coverage, so the temperature difference in areas with good vegetation coverage is also small.

Another thing I have to say is that there are many large cities with large population, and the urban heat island effect (the temperature in the urban area is higher than that in the suburbs) directly affects our judgment on the temperature difference. If you walk from the city to the suburbs, it is normal to feel much colder.