I would not anyone work on my house doing windows in that temp. You will
have rushed work, you cant caulk, my windows were done in fall and the
warmth, some were gone 5 hrs due to problems.

A rushed job can mean a bad job and if not leveled, plumb, and squared
to less than factory warranty maximums you will loose Any warranty you
may have had. Many warranties give 1/8" max or you have no warrany . My
hack redid 4. Luckily it was warm out.

In those temps you will loose your heat savings for that month maybe
costing your savings. Weigh the costs you may not save but loose.