airbag signal light

I just notice a weird thing this morning when driving my 04 camry. It was cold and dark outside, and I suddenly notice there is a very faint red from the airbag signal on the dashboard. I stopped at a gas station to check and it was not visible under the bright light. I restarted the car, the light came on and went out after 6 seconds as usual. But I found that it was gone after driving on highway. In the daytime, I restarted the car again and did not see such thing happened. Now I wonder if this could be a fuse issue due to cold weather or just some sort of light reflection issue.