It's much. much worse. It's not easy to describe. Most newbies look at temperatures and dismiss the winters in this area as no problem compared to their home countries.
Take a look around. The buildings are made to dissipate heat from furnace like summers. There's no insulation and any heat will come from small air conditioner units rather than central air or radiators. A low temperature in Changsha is anything under 0C, the problem is that there is no place to get warm. Your house, school, restaurants are all cold. You can't warm up. People go outside during the day to warm up in the sun. All public places will have icy cold running water.
When you are outside, you are moving around but inside you might be sitting around. I wear more clothes to watch TV than to take a walk. If i spend a lot of time at my desktop computer my mouse hand will start going numb with cold.
Inside during the day is quite cold but the evenings are better because more people are home in their apartments, maybe cooking etc. It's strange to have the temps go up in your house as the sun goes down outside
There is very little snow, just cold rain or freezing rain and it's humid all the time.
I visit mt home country every Spring Festival because A Canadian winter is far more comfortable. I never bothered with long underwear until I came here.
Oh and make sure you have the clothes and blankets etc. You might be ok with electric heaters but when the power goes out ............ and it will.
长沙天气有太热有太冷 chángshā tiānqì yǒu tài rè yǒu tài lěng