Updated documentation to include information on the use of JSON.

README.md

@@ -77,12 +77,13 @@ You can override this behavior by adding `?u` or `?m` to a URL like this:
 
 ## Supported output formats
 
-wttr.in currently supports three output formats:
+wttr.in currently supports four output formats:
 
 * ANSI for the terminal;
 * ANSI for the terminal, one-line mode;
 * HTML for the browser;
-* PNG for the graphical viewers.
+* PNG for the graphical viewers;
+* JSON for scripts and APIs.
 
 The ANSI and HTML formats are selected basing on the User-Agent string.
 The PNG format can be forced by adding `.png` to the end of the query:
@@ -112,6 +113,53 @@ In this example:
 
 ![Picture with weather data](https://pbs.twimg.com/media/C69-wsIW0AAcAD5.jpg)
 
+## JSON output
+
+The JSON format is a feature providing access to wttr.in data through an easy-to-parse format, without requiring the user to create a complex script to reinterpret wttr.in's graphical output.
+
+To fetch information in JSON format, use the following syntax:
+
+    $ curl wttr.in/Detroit?format=j1
+
+This will fetch information on the Detroit region in JSON format. The j1 format code is used to allow for the use of other layouts for the JSON output.
+
+The result will look something like the following:
+
+    {
+    "current_condition": [
+        {
+            "FeelsLikeC": "25", 
+            "FeelsLikeF": "76", 
+            "cloudcover": "100", 
+            "humidity": "76", 
+            "observation_time": "04:08 PM", 
+            "precipMM": "0.2", 
+            "pressure": "1019", 
+            "temp_C": "22", 
+            "temp_F": "72", 
+            "uvIndex": 5, 
+            "visibility": "16", 
+            "weatherCode": "122", 
+            "weatherDesc": [
+                {
+                    "value": "Overcast"
+                }
+            ], 
+            "weatherIconUrl": [
+                {
+                    "value": ""
+                }
+            ], 
+            "winddir16Point": "NNE", 
+            "winddirDegree": "20", 
+            "windspeedKmph": "7", 
+            "windspeedMiles": "4"
+        }
+    ], 
+    ...
+
+Most of these values are self-explanatory, aside from `weatherCode`. The `weatherCode` is an enumeration which you can find at either [the WorldWeatherOnline website](https://www.worldweatheronline.com/developer/api/docs/weather-icons.aspx) or [in the wttr.in source code](https://github.com/chubin/wttr.in/blob/master/lib/constants.py).
+
 ## One-line output
 
 For one-line output format, specify additional URL parameter `format`: