It was a bit above zero, but I don't think it was raining (but didn't pay too much attention to the weather: it was probably sunshine). I did check the snow depth in the morning to get a feel for how much longer skis were needed, and I'd expect the elements to wear off the snow first and the ice after that, once the insulating snow layer is gone, as the melting from below is rather limited. Once the snow turns into slush it ought to eat into the ice, making it brittle.
In general, it seems water temperature is changed far too quickly based on the air temperature (one day you can swim without getting cold, the next day you get cold, and the day after you don't get cold again), and the water temperature should not be affected at all before the ice is gone, as all the heat is used to melt the ice before the water temperature gets any "leftovers" to speak of.
Going from "no worries" to "you're dead if you move, and you're dead if you don't" shouldn't happen over the time span of normal ice activities such as active fishing or skinning/butchering an elk (I'm not saying you should be able to take all, or even any, of that elk or fish with you), at least not without either a warning before starting an activity, or an interrupt during the activity, allowing you time to get out. After all, the player has only crude measures with which to make estimates (snow depth, weather, and date, plus any observed holes in the ice and cracking sounds, of course), while the UrW character should be well versed in additional signs of nature, such as the thickness and texture of the ice.
Another horror scenario would be if you're crossing a big lake and suddenly get trapped half way because the ice has deteriorated (I don't know if the check is done every overland map step or only on the transition from land to ice).
A possibility would be the addition of a warning that the ice isn't dangerous now, but can be within 24 hours if there's heavy thawing, or immediately if you load up to your carrying limit, i.e. basically a "warning zone" in addition the the current "danger zone".