Temp diff outside to attic

i am having ventilation problems. the outside current temp is 26 deg. F, and the temp in my attic is 48 deg F with 49% humidity. how much is to much of a temp diff?

It’s not so much the temperature as it is the humidity. You don’t want warm moist air condensing on cold surfaces at the underside of the roof.

You mention 48° with 49% rel humidity. There are tables in my college textbooks that can tell you what the rel% humidity would be at 26°. It will be higher, but you don’t want it to reach 100%.

In theory it should be 26 deg in your attic also.
I don’t know what an acceptable temp difference is