I’m attending campus day on Monday and I am currently packing. The high on Monday is 39 degrees. Would it be improper to wear warm athletic pants?
Nope, it would be fine.
It has a chance of snow on Monday. Just be prepared.
Keep in mind that a large portion of Campus Day (~2-3 hours) involves walking around parts of campus, and with the wind in A2 that 39 will feel a lot colder. Definitely dress as warm as you need 