Just switch your router from WPA/WPA2 over to WEP and keep fingers crossed
According to numerous Apple customers writing on the company’s official forum, the iPhone 5 has Wi-Fi problems. While some users haven’t experienced any issues, thousands seem to have at least one complaint regarding the phone’s wireless connectivity.According to users who attempted to troubleshoot the issue on their own, the fix is relatively simple. All you need to do is switch your router from WPA/WPA2 over to WEP.
It isn’t clear whether this is a software-bound problem, or something relating to the hardware. In case it’s the latter, customers will have little to do except maybe try to get a replacement iPhone 5 from Apple.
If the issue is software-related, then Apple’s upcoming iOS 6.1 is likely to fix it. Let us know in the comments how your Wi-Fi turns out after switching over to WEP (as detailed by Gizmodo).