I would like to second this problem as well. I have default weather engine and just did a reinstall of FSX on a clean Win7 install.
To add to the information above if I select downloadable weather (static or 15min) I get the above issue as well as if I clear all weather.
Further if I download weather and then go to user defined and click on the FLL weather station it will tell me "moderate precip" whereas all the others (HWO, MIA, boca) all show fairly reasonable weather to whats outside my window.
I have the day off so if you need team viewer or video of the issue contact me!.
Thanks
Dr. AC