-18°C is very cold weather:)
This is a popular topic for jokes here. People in Siberia are used to winters with -30°C, and they assure us that our frosts are nothing. But Siberia has a continental climate and the air is dry. When they come to visit us, they complain about the terrible cold.
The pictures do come out crisper when it is freezing - the air is more transparent. Thank you very much!
I guess it is all relative, where i grew up back in NZ, a cold day in winter it may drop to 0C overnight
and yes the humidity can really affect how the cold tempos feel