Using Weather Data to Change Your Website’s Appearance through PHP and CSS

Using Weather Data to Change Your Website’s Appearance through PHP and CSS

from CSS-Tricks by Guest Author

This article is co-authored by David Walsh


Inspiration for this idea came from a comment by Andreas.
Using a little magic and trickery (read: PHP and CSS), we can change the appearance of a website automatically based on the weather outside, in real time! In the example site we have created, the header graphic will change to one of four different styles based on Sunny, Rain, Snow, and Cloudy.

Step 1: Designing your weather graphics

Our example site changes header graphics as as well as an icon in the sidebar to describe the weather. For the sake of example, we only created four different weather scenarios, defaulting to sunny.

Step 2: Retrieving the weather information

Yahoo! has an API for weather information. We can tap into this very easily using an URL formatted like so:
http://weather.yahooapis.com/forecastrss?p=97211&u=f
The 5-digit number is your Zip Code and the “f” stands for “Fahrenheit” (change to “c” for “Celsius”). The information comes in XML format and it’s up to you how you want to parse the data. Since the only bit of information we care about is the “yweather:condition” element’s “text” attribute, We’re going to avoid creating an XML parsing object and use a short regular expression.
Once the regular expression returns the yweather element’s text, we’ll use str_replace() and strtolower to format the string into a representative CSS class.

Step 3: Turning the weather information into an CSS class

Here is the PHP code:

<?php

 /* get xml, find match */

 /* get the weather from Yahoo */
 $data = get_data("http://weather.yahooapis.com/forecastrss?p=97211&u=f");

 $weather_class = format_result(get_match('/<yweather:condition text="(.*)"/isU',$data));

 /* debug to see what we got back */
 //echo '<pre style="background:#fff;font-size:12px;">['; print_r($weather); echo ']</pre>';

 /* format the result */
 function format_result($input)
 {
  return strtolower(str_replace(array(' ', '(', ')'), array('-', '-', ''), $input));
 }

 /* helper:  does regex */
 function get_match($regex,$content)
 {
  preg_match($regex,$content,$matches);
  return $matches[1];
 }

 /* gets the xml data from Alexa */
 function get_data($url)
 {
  $ch = curl_init();
  $timeout = 5;
  curl_setopt($ch,CURLOPT_URL,$url);
  curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
  curl_setopt($ch,CURLOPT_CONNECTTIMEOUT,$timeout);
  $xml = curl_exec($ch);
  curl_close($ch);
  return $xml;
 }

?>

Now we have a variable we can echo out that is representative of the current weather at the zip code we provided:

<div class="header header-<?php echo $weather_class; ?>">
 
</div>

Step 4: Code your CSS for each of the classes

.header {
 width: 782px; height: 150px;
 /* DEFAULTS TO SUNNY */
 background: url(images/header-sunny.png) no-repeat center center black;
 }
 .header-rain {
  background: url(images/header-rain.png) no-repeat center center black;
 }
 header-snow {
  background: url(images/header-snow.png) no-repeat center center black;
 }
 .header-sunny, .header-fair {
  background: url(images/header-sunny.png) no-repeat center center black;
 }
 .header-partly-cloudy, .header-cloudy, .header-mostly-cloudy {
  background: url(images/header-partlycloudy.png) no-repeat center center black;
}

Step 5: Extending the idea

Notice that we use the “partlycloudy” graphic for the weather conditions of “partly-cloudy”, “cloudy”, and “mostly-cloudy”. It’s up to you how specific you want to get. Here is a full list of the possible weather conditions from Yahoo!:

0   tornado
1  tropical storm
2  hurricane
3  severe thunderstorms
4  thunderstorms
5  mixed rain and snow
6  mixed rain and sleet
7  mixed snow and sleet
8  freezing drizzle
9  drizzle
10  freezing rain
11  showers
12  showers
13  snow flurries
14  light snow showers
15  blowing snow
16  snow
17  hail
18  sleet
19  dust
20  foggy
21  haze
22  smoky
23  blustery
24  windy
25  cold
26  cloudy
27  mostly cloudy (night)
28  mostly cloudy (day)
29  partly cloudy (night)
30  partly cloudy (day)
31  clear (night)
32  sunny
33  fair (night)
34  fair (day)
35  mixed rain and hail
36  hot
37  isolated thunderstorms
38  scattered thunderstorms
39  scattered thunderstorms
40  scattered showers
41  heavy snow
42  scattered snow showers
43  heavy snow
44  partly cloudy
45  thundershowers
46  snow showers
47  isolated thundershowers

For this example, you’ll notice we also used a hard-coded zip code that must be changed in the PHP in order to change where the website will be basing it’s weather appearance on. But wouldn’t it be cool if the website knew the zip code of your visitors and would change the appearance of the site based on their weather instead of your weather? That kind of coding requires services and expertise beyond the scope of this tutorial, but a quick Google search brings up some services that could probably make this happen like IP2Location.
Have fun! - and let me know if anyone actually uses this, I’d love to see what you did with it.