You can't receive WeChat when the mobile phone has no signal, but can you receive SMS?

Yes, but it depends on the actual situation. If there are no two signals in mobile communication, they cannot be received, but if the communication signal is weak, you can receive SMS, but you may not receive WeChat. Wechat is a network signal, and communication signals precede network signals. You can receive short messages by phone, but you may not be able to accept network messages.