Mysterious nightly Data Usage charges iPhone

Yeah... that was a lot of futile effort. There is no 'Apple Facebook page'.

Still, you might want to turn off a few things such as location services and notifications. There's one particular item that keeps running on people's phones, it's the time zone detection, which you can turn off anytime you want in your iPhone settings menu.

An alternative would be turning on Airplane Mode while leaving WiFi on, if you need to stay connected. Or just the Airplane mode. This will prevent any unwanted data transfer overnight.

Yeah... that was a lot of futile effort. There is no 'Apple Facebook page'.

Still, you might want to turn off a few things such as location services and notifications. There's one particular item that keeps running on people's phones, it's the time zone detection, which you can turn off anytime you want in your iPhone settings menu.

An alternative would be turning on Airplane Mode while leaving WiFi on, if you need to stay connected. Or just the Airplane mode. This will prevent any unwanted data transfer overnight.

I don't have an answer from AT&T or Apple, but I have a resolution that requires Apple Developers to implement, and that is simply to check first for Home Network or Primary Network first and if present use that method instead of 3G or 4G to transmit data.  However, this requires Apple to implement these changes into their iOS, why they don't do this now instead of later I don't understand. I talked extensively with AT&T technical support and they tried to tell me that this might impact users who are not home, and I simply told them that would not hurt them at all if the system just checked if not at Primary Network to simply use the 3G or 4G, it just adds one layer of check point first before selecting the method of transmitting the data and this would be welcomed by users greatly but means less revenue for AT&T.....

Hmmmm do you think AT&T would even want that??? No reason for them to push this to Apple, it requires the Apple user base to push this change in the iOS, under the network section just be able to lable one network as your primary and to check for that one's presence before sending data.

For Apple this might mean more battery usage which means poorer battery performance, so there might be a trade off, but if you have your phone at night, at home, plugged into your iHome or via Power charging then this alone would save millions of us data usage that is unexplainable from Apple or AT&T but is ever increasing with each iOS update we get. 

I don't have an answer from AT&T or Apple, but I have a resolution that requires Apple Developers to implement, and that is simply to check first for Home Network or Primary Network first and if present use that method instead of 3G or 4G to transmit data.  However, this requires Apple to implement these changes into their iOS, why they don't do this now instead of later I don't understand. I talked extensively with AT&T technical support and they tried to tell me that this might impact users who are not home, and I simply told them that would not hurt them at all if the system just checked if not at Primary Network to simply use the 3G or 4G, it just adds one layer of check point first before selecting the method of transmitting the data and this would be welcomed by users greatly but means less revenue for AT&T.....

Hmmmm do you think AT&T would even want that??? No reason for them to push this to Apple, it requires the Apple user base to push this change in the iOS, under the network section just be able to lable one network as your primary and to check for that one's presence before sending data.

For Apple this might mean more battery usage which means poorer battery performance, so there might be a trade off, but if you have your phone at night, at home, plugged into your iHome or via Power charging then this alone would save millions of us data usage that is unexplainable from Apple or AT&T but is ever increasing with each iOS update we get. 

To answer some of your questions, which ARE answered in the other thread you posted to if you can slog through thousands of messages, WiFi is turned off when the phone goes to sleep to conserve battery, unless the phone is connected to power. If it weren't the battery would run down in a few hours. WiFi requires a continuous data connection at a steady 30 mw drain whether data are being transferred or not, compared to cellular data, which only uses power when sending.

As to why more usage, more apps use more data. And apps can run in background when the phone is asleep. News apps do, for example. As does Facebook. Many free apps are free because they collect data from your phone and "phone home" with it so they can resell it. I saw an article on this a couple of weeks ago, which, unfortunately, I can find right now.

And finally, if you see data charges on your bill with late night time stamps that does NOT necessarily mean data were transferred at the time of the time stamp. That is the time accumulated data usage is posted to the billing system. To find out when the data transfers actually occur you need a monitoring app such as Dataman.