With Celsius it's all nice and round numbers unlike the mess called fahrenheit:

0°C—black ice, snow, be careful on the road and you probably want to wear gloves and a hat
0...10°C—a bit chilly, but you can leave your hat home
10...20°C—pleasant, but not quite tee-and-shorts yet
20...30°C—nice summer weather
30...40°C—holy crap it's hot!
40...50°C—are you fucking kidding me?
50+°C—my proteins are starting to denature...
100°C—good sauna
110°C—finns think it's a good sauna
120+°C—finns think it's getting a bit too hot in the sauna. Italians tend to vaporize in sauna (speaking from experience)
...
0...-10°C—a pleasant winter weather
-10...-20°C—getting a bit frosty
-20...-30°C—finns think it's a pleasant winter weather
-40°C—vodka freezes. Russians and finns agree it's getting a bit frosty
-50°C—getting a little hard to start your Uazik in the morning in Siberia due to engine oil solidifying
-60°C—researchers in Antarctica all agree it's getting a bit frosty and someone should close the window