That‘s one of the biggest health myths around. Cold weather does NOT weaken your immune system AT ALL (except if you‘re actually hypothermic, which is very different from just feeling uncomfortable). It’s the CONDITIONS that RESULT from cold weather that actually cause those infections to ramp up in winter (think more people staying inside in enclosed spaces).

Thank you. The real myth is the idea that it's a myth cold weather doesn't cause colds.

Cold, drier air in contact with your mucus membranes lowers your defenses against viruses. It's that basic. In just regular cold air -- not hypothermia.

Thank you! It always was astounding to me how people could argue with so much vigor and conviction that something as complicated as the immune system could not possibly be affected by something as basic as temperature changes.

People get colds in the winter time because they are all packed inside (without proper ventilation (ha!)).

Now we have AC in trains and buses, so the windows are closed too. I'd expect a more even flu season.

I'm not a biologist / epidemiologist but maybe the mutation of flu strains are synched up with this annual human behavior such that by the end of the winter most everyone has developed immunity for the current strains. By the next winter the mutations have happened again and the cycle repeats.

I'd love for this random thought to be confirmed / corrected.

for that to be true, the flu would be have to be more than than a unicellular organism in order to know what seasons are. do you have a proposal for how that would work? I'm sure there's a Nobel prize for you ($1 million dollars!) if you have something.

Unicellular organisms can be quite intelligent. Just because it has a single cell doesn't mean it doesn't have a mind!

Now the flu is virus, but it could still have a mind to perceive the seasons in it's infected running state.