Why not use a JSON parser like this
to extract the data from the JSON you get.
If your response is too long you can use the response template of the webhook to boil it down to the parts you are interested in and then only pass that to the JSON parser on your device.
e.g. to only get the coordinates your response template could look like this
{ "lat": {{coord.lat}}, "lon": {{coord.lon}} }
in order to get a feeling for handlebars you could use an online handlebars parser like this
where you paste your raw response into the context box and type your test template into the template box.
When you then hit the Compile Handlebars Template you’ll see what comes from that.