in/on cold winter days

[joham]

Carrying the heavy boxes made me sweat even in/on cold winter days.

Can 'in' also be used in this context, or some other context?

And in 'Keep warm during/in/on cold winter days' are all three prepositions fine?

Thank you in advance.

 

[emsr2d2]

Carrying the heavy boxes made me sweat even in/on cold winter days.

Can 'in' also be used in this context, or some other context?

And in 'Keep warm during/in/on cold winter days' are all three prepositions fine?

Thank you in advance.

I would use "on". I might use "during" but not often. I would not use "in".