system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens to the common cold during the off season, where does it reside and why/how does it come back?
gpt
Colds spread more in winter because people tend to stay inside in closer contact; they don't completely die out over the summer, there's just less people infected. When it gets cold out the infection rate increases, and everyone gets a cold again.

It's also worth noting that plenty of countries are always cold, and that summer and winter are reversed between the North and South hemispheres. Even if colds did completely die out in summer there would still be people infected somewhere else.