I had the same thing with AT&T DSL. It means the DSL isn't syncing. And, it did seem to occur more often during wet weather. The line techs all told me that wet weather affects DSL.

But, I first got DSL in 2000, and never had issues until about a year ago. I quit rebooting the DSL (shutting down for 3 minutes), and started calling the tech department while it as still down, so they could test the lines. The funny thing was that by the time I punched my way through their menu prompts, the red light had turned back to green, so when they tested, the line appeared ok. I finally started keeping a log of every time it went out. And, by that time it was going out 3-4 times each day.

When I had a week's worth, I asked them to send a tech. He looked at my log, knew there hadn't been wet weather for all of the prior 7 days, and actually started tracing the line. He found a short where the line connected to the card in the phone box.

It has worked great ever since and that was about 3 months ago. Long story short, try keeping a log that you can show the line tech when he comes out.