Ovr40,
Hopefully you'll get more direct feedback from those that were there. From previous climbs of Rainier I can tell you that observation of a typical pattern the weather is following might help. For example, last year on a three day climb we observed the same pattern every day whereby early AM through late morning the mountain would be socked in. And each afternoon it would clear up nicely. So if you have a good handle on what you're seeing, and the forecast (such as no strong system moving in), you could be fine carrying on. Of course there's the risk of misreading the weather, and many would prefer to be more conservative.
Best of luck!