titacgs

This plugin/widget allows you to insert weather status in your sidebar. It connects to World Weather Online to get weather forecasts. It shows the current temperature, max and min. You can choose the temperature scale, options are celsius and fahrenheit degrees. Also, you can get results from 1 to 5 days.
It has a really simple html markup:
<ul>
<li>For one result</li>
</ul>
22 °C
Min 20 °C
Max 32 °C
<ul>
<li>For more than one, displays current temperature and a table</li>
</ul>
22 °C
 Date 
 Min. 
 Max.
 05/22 
 Min 20 °C 
 Max 32 °C
 05/23 
 Min 23 °C 
 Max 33 °C
You can style it by adding the proper CSS for each id to your style.css file: temp_actual, temp_max, temp_min
<a href="http://blog.titacgs.com.ar/world-weather-plugin-para-wp/" rel="nofollow ugc">Visit the plugin page</a> leave questions/comments/fixes.
Also, if you like this plugin <a href="https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=QZTRL5AJ35EHG&lc=VE&item_name=World%20Weather%20Plugin&item_number=WP%2dPlugin&currency_code=USD&bn=PP%2dDonationsBF%3abtn_donateCC_LG%2egif%3aNonHosted" rel="nofollow ugc">you can donate some money!</a>

World Weather Widget

This plugin/widget allows you to insert weather status in your sidebar. It connects to World Weather Online to get weather forecasts.

Theme Egg

This is Weather Forecast widget plugin, You can add widget by installing this plugin. 
After Installing this plugin go to Appearence>>Widget and add widget to your sidebar.

Weather Forecast

This is Weather Forecast widget plugin, You can add widget by installing this plugin.

World Weather Widget vs Weather Forecast