@peter, thanks for your detailed answer. It makes the decision for me easy to opt for the local Weather Service with my WU compatible PWS (Netatmo).
In the meantime I have WeeWX and the OpenSprinkler-Weather service running on the same Raspberry PI. It is definitely not needed, but I have chosen the Rasbperry Pi 3 Model B+ to be up to date with dual-band 2.4 GHz and 5 GHz wireless LAN.
Testing the OpenSprinkler Weather Service shows that the service is running correctly:
http://192.168.178.39:80/weather1.py?loc=49.47369,10.94380&wto=”h”:100,”t”:100,”r”:100,”bh”:70,”bt”:65,””br”:0
results in:
&scale=66&rd=-1&tz=56&sunrise=310&sunset=1283&eip=3232281125&rawData={“h”:81.33,”p”:0,”t”:59.5,”raining”:0}
One last thing: To configure the OpenSprinkler DC 3.0 to use the Local Weather Service I have to set the Weather Service IP and PORT (Default: weather.opensprinkler.com) to 192.168.178.39:80? TheJavaScript for the UI (default: https://ui.opensprinkler.com/js) remains unchanged? Is the OpenSprinkler System Diagnostics thereafter showing the data received from the Local Weather Service?
Realized that I have to use PORT 80 to answer requests coming from OpenSprinkler. Unfortunately the OpenSprinkler System Diagnostics still shows no Last Succesful Weather Call.