Freezing warning does not appear outside of winter.

It got a bit better because now if the ambient temperature is below 0, you'll get the warning even outside of winter, from any source, unlike before. But if the ambient temperature is equal or above 0, then wetness, endothermic fires, etc, any other source that isn't the Ice Crystaleyezer (because that's basically ambient temperature being overridden) will not show the warning.

local all_up_thresh = {5, 0, -5, -10}

(temp < 0 or TheWorld.state.iswinter or GetLocalTemperature(self.owner) < 0)

At this point it just begs the question why these checks are there, it's just taking away feedback from the player. If a different effect played, then it'd make more sense?

The heat overlay has similar checks but they're even more redundant there because the first of the checks:

local all_up_thresh = {65, 70, 75, 80}

(temp >= 65 or TheWorld.state.issummer or GetLocalTemperature(self.owner) >= 65)

Is the same as the lowest threshold, so it always goes through regardless, making the other two checks not really change anything, and the local temperature check just wastes performance.