Still running stable all the time the old version with latest Beta Domoticz V3.8942 on Pi3:
2018-02-23 19:23:26.896 (Buienr-VDaal) Initialized version 1.0.1, author 'ffes'

Are you running the beta version? That's necessary.
Have you done the following steps (Raspberry Pi)?
sudo apt-get update
sudo apt-get upgrade
sudo apt install python3.4
sudo apt install libpython3.4
sudo apt install python3-dev

Whats in the Domoticz log?

Running stable here.

Still OK,
2017-02-19 20:03:10.161 (Buienr-VDaal) Initialized version 1.0.1, author 'ffes'

Localtest.py gives:
Found Meetstation Voorschoten at 8.2 km from your home location

Always Voorschoten? Domoticz for me configured for Arnhem.

Nice site for location info:
http://nl.mygeoposition.com/

hi ffes, Delete hardware in domoticz-hardware, delete buienradar directory in plugins and install again. Restart domoticz and add hardware. Works perfect: 2017-02-19 19:09:01.646 (Buienr-VDaal) Initialized version 1.0, author 'ffes' 2017-02-19 19:09:01.699 (Buienr-VDaal) Retrieve weather data from ...

Install the plugin again and it's working now. Thnx!
Maybe you can add in the documentation that you also have to install python3-dev? Thanx for this in previous post.

Today I installed Buienradar on the latest beta V3.6749. Buienradar is in the hardware, but after configuring in de log will come the error: 2017-02-19 12:37:53.738 Error: (Buienradar) failed to load 'plugin.py', Python Path used was '/home/pi/domoticz/plugins/domoticz-buienradar/:/usr/lib/python3.4 ...