Since the cold weather started, my battery warning light stays on for a few second to a minute, after I start the car. It then fades as I press on the gas, and then goes off...until next time... which can be a couple of days or more later

This doesn't happen every time, but it seems to happen more often the colder it is (32 degreees F. or lower).

At first, I thought that it could be because the alt belt was hard and that it wasn't turning the alt properly. But when I look under the hood, the belt seemed to be driving the alt allright.

Any ideas?

Thanks

Jean