Can't pair reset iWatch to phone as it is not updated and not connected to wifi.

Hello, I have an issue with my iwatch. I lost my watch for a a few months and when I found it, it would not pair to my phone. I factory resetted it, and now it is not connected to the internet, it needs an update, and I can't pair it to my phone. Help!! What can I do to pair my iwatch that needs an update to my phone if it is factory rested and it is not connected to the internet?