In mid-January, when you haven't see the sun for a month and it's somewhere around 0 outside, ask your children if they'd be happier if it were 70 and sunny.
They lived in Portland, OR before , so they are used to not seeing the sun.
And we're from Portland, Maine... Last year, they were rather peeved at pitiful amount of snow we got
ETA: As far as things to do, it's really not bad at all. There are all the typical things (just got back from soccer and now they're off to swim at the Y,) and this morning was spent at the farmers' market and later this afternoon, we're going out to a pumpkin patch to pick our own (we can do the same at Christmas with cut-your-own tree farms.) There's a nice childrens/science museum, the Syracuse zoo is only an hour away, and Cornell has lots of smaller museums. There are youth singing and theater groups and athletics through the IYB. Lots of parks, outdoor recreation, etc. And the schools are excellent, and most have extensive extra-curricular activities: I have four kids in four schools (ages 8 - 14) and we're busy almost every night with something.
And we still have time for a beer/movie/dinner with our law school peers now and again.
Also, while Ithaca is small, it's not that small. I grew up just outside of New Haven, and there's much more for my kids to do here than there was for me in suburban Connecticut. It's also has a much more reasonable CoL than almost all the other T14s (maybe not UVA and/or Mich) and having things to do means nothing if you can't afford to do them.