Wi-Fi is too weak?

Sorry, but that is just not enough information in order for us to be able to assist you with a potential solution.

• Writing an effective Apple Support Communities question - Apple Support Communities

For example, some things that would be helpful:

• Which exact model is your iPhone and what version of iOS is it running?
• Is this issue specifically with Wi-Fi or with cellular as well?
• How are you measuring wireless "speed?"
• Was this always a problem or just started to happen? For the latter, did you recently update this phone?
• What have you tried, so far yourself to resolve this, so that we don't try offering potential solutions that may not have already worked for you?

Perhaps the steps in this article will help:

If your iPhone, iPad, or iPod touch won't connect to a Wi-Fi network - Apple Support