Weather Forecast Endpoint

Description

Create a REST API endpoint that gives the weather forecast for next day.
The forecast should be retrieved from any free third party provider (API) such as:

Required Features

Your endpoint would receive as request parameters:

the location (required).
temperature unit with available values Fahrenheit or Celsius (required).
a weather forecast provider identifier (optional).

And the response of this endpoint should include the following:

the temperature.
the weather description (e.g. "Overcast clouds").

Optional Features

Unit testing.
Option to retrieve weather forecast from more providers.
Caching to reduce the requests to third party providers.
Use Docker.
Input validation.

Coding Standards

Please keep in mind these coding standards:

The JSON API specification.
The PSR-1 and PSR-12 coding standards.

What you should submit

A program written in PHP 7.0+ using any Framework you like.
A brief document with an overview of your design.

Do your magic!