Oil Consumption

the cold may have something to do with it but it shouldn't use that much from the cold chance are the rings are a little bit worn and it is burning some oil, but adding some every 2-4 weeks you wont notice any smoke. if you can keep it warm, cold starts are always hard on vehicles cause the oil has to warm up to get to the top of the engine (possible cause of your worn rings). another possiblity is it being a '98 it has a few miles and is just generally worn.

Low temperature is not a function of oil consumption as long as the ambient temperature range matches the oil's multi-grade viscosity rating.

In other words, the engine will not use more oil when cold, in fact if anything it would use less oil when cold.

The first thing to consider is not "worn rings", and in any case it's the oil control ring that regulates cylinder oil, and not the compression rings, and the oil control ring is not likely to be worn before the valve seals.

Thus the valve seals are more suspect than the oil control ring.

All assuming of course, no oil leaks which I should point out, do not always show easily.