Go to "http://www.menet.umn.edu/~curt/weather/x-plane.html".

Now download the file "USA.rwx". ("File:Save As" in Netscape).

This file contains the weather AT EVERY AIRPORT IN THE COUNTRY THAT REPORTS WEATHER (over 1,200 of 'em!), AND IS UPDATED EVERY HOUR. In other words, it is a REAL-TIME, UP-TO-THE-HOUR synopsis of the weather for the ENTIRE COUNTRY.

Just drop this file into the X-Plane folder and X-Plane will use it to set the weather as you fly, and the weather briefer will give you an up-to-date weather breifing before your flight.