How long for an iphone to die?

I left my phone in my school locker. Probably around 40%. I have my alarm set for 630 and i don't want it ringing in the morning at school… Will it be dead by overnight? How long does an iphone 4 to die in sleep mode?

Very long time, mine hardly drops 1% overnight. I imagine cold weather would make it drop faster.

  • Why does my iPhone battery die so quickly? I had my iPhone for about a year and a half, and recently I've noticed that the battery is draining incredibly fast. I've always had it on 3g internet/Wi-Fi and the battery never died this fast so I don't know what the exact problem is. I charged it to 100% yesterday and I only used it for maybe about 10 minutes and left it untouched for the rest of the night. Today when I woke up the phone was dead. I haven't changed the settings or anything fyi.
  • Why does my iPhone battery die so fast? I have boost magic, which is supposed to help my battery last longer, and I kill all my apps when I'm done using them. I go from 100 at 8am and I'm at 60 by 9:30am. And I hardly use it too, just to look up information quickly and I just set my phone aside. I let it go down to 20% battery and let it charge over night. It just started doing this recently. I also keep my brightness to pretty much 0 with the auto brightness on. And it still dies fast. What can I do?
  • Why does my iPhone 4s' battery die so quickly? I'll have it fully charged when I wake up at 8, then it's basically almost dead around 1 in the afternoon. It use to not die this quickly. But now it's like crazy how fast it dies! I'm on Twitter a lot and I text a lot. But I use to always do that too, and it never died as quickly as it does now. Any tips to help save battery?
  • Why does my iPhone 4S battery die so quickly? - 1 Everyday I turn off all the running apps and shut down my phone which is at 100% and then when I get home from school it's at 60% without me doing anything. My friend Hannah's did the same thing and her friend did something to it and now it loses only like 4% in 6 hours while playing on it all day but i don't know what she did. Do you know what she might of done or how you can fix this?