Or get long drop brakes and 650b wheels, then you can fit mudguard and still be lighter than your original set-up, like this Trek road bike converted to 650b, room for 38mm and mudguard.
The bike simply feel a little more nimble to ride, a 650b with 42mm is the same as a 700c with 23mm, so with 38mm tyres, you'll benefit from a slightly lower BB, which in itself not a problem (even with clip and strap pedals).
it's cheaper than having to get a winter bike, or a different frames.
Or get long drop brakes and 650b wheels, then you can fit mudguard and still be lighter than your original set-up, like this Trek road bike converted to 650b, room for 38mm and mudguard.