Why are at hand more cranium colds and virus around surrounded by the winter? (UK)?

I think the conventional viewpoint is that people are close together and inside more normally during the winter.
My theory is that the school are back.
Anyrate, I go out to spread my germs around. What happens surrounded by Australia when it is sunny in winter?Why are at hand more cranium colds and virus around surrounded by the winter? (UK)?
I believe that it is becuase since it is cold outside, race tend to stay in more, allowing for unforced spreading of viruses.
Don't quote me on it

R
Personally I surmise it is more scientific - this may not be true but the white blood cell that help argue of infection etc in your body rely on enzymes and catalysts to function probably.
In colder temperature they don't work as well and start out you more prone to infection and illness. This is bad the top of my head, but make sense.
because there is more cold nouns for us to breathe in and that chills the system major to COLDS and in some cases the FLU