My Beargrease with 27.5"x3.8" is very nimble on trail year round. I'm old enough that I don't ride aggressively on trail--64--but the Beargrease could certainly do that, as could many other fatties. The thing is, a fattie can do anything an MTB can do, but not the other way around. I have my fat bike and two gravel bikes, one of them is at work for when I get a chance to get out, and I'm quite pleased with that small stable.
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Don't complain about the weather and cower in fear. It's all good weather. Just different.