[cappy]

Just crunched a few numbers. Checking the Weather raises the discharge rate by approximately 400mA (Of course, this number would vary, depending upon what application is accessing the Internet). In my case, the connection is only on for a few seconds and then becomes inactive. So battery drain is minimal. But if the connection is left open for 10 minutes, the effect is significant.

400mA x 1/6 hours = 66.67mA drain on battery
66.67mA/1340mA=4.975% drain in 10 minutes
4.975% * 6 = 29.85% per hour drain

I other words, if the Data Connection remains active for an hour, the battery level will drop by 29.85%.

Limited information to rely on. But the calculation is revealing.