OK, that’s an interesting discovery — I had not thought about changing the port number would affect the weather script. I will check this tomorrow.
For port forwarding: external port number does not have to match the device port number. For example, you can tell the router to map external port 8080 to OpenSprinkler’s port 80. So when you are out of your home network, use http://wan_ip:8080 and the router will map that to http://os_ip:80