My alternator light starts flickering when the car first cold started, and after the car was warmed up, the light is gone. It never happened when the weather is warm.

This happened only when the weather is not warm (below 50). It happened once last year.
This year, it happened TWICE already. It's not like the light will flicker on every cold start, just in rare occasions.

What's your diagnosis on this? Choke heater?

Any similar experiences, and how it was fixed?

Thanks,