Dan Mossop

The perfect way to show current conditions and a 3-day forcast in your sidebar, for a location of your choice. Great for travel sites, town or city sites, etc. It looks good, takes up little space and is easy to set up.
The widget uses accurate weather data from World Weather Online.
<h4>About the Weather Widget</h4>
The Weather Widget by Calcatraz is a compact WordPress weather widget for your sidebar. It has a neat, neutral design which fits in with almost any site. For the location of your choice (city, town, coordinates, ip address, etc) it shows the current weather conditions on the left and a 3-day forcast on the right.
The widget can display temperatures in both celcius and fahrenheit scales. It can detects the user’s language and shows the appropriate scale, or use a predefined scale. It also allows the user to switch scales, and remembers their preference.
There are now two styles: the default wide style (260 x 58px), and the new square style (133 x 116px) suitable for narrower sidebars.

Weather Widget by Calcatraz

A simple, compact weather widget which displays current conditions and 3-day forecast for the selected location.

tiempocom

This plugin provides you the daily weather forecast for the locations you choose. 
With no configuration, you will be able to manage widgets and shortcodes with no hassle.
Features:
<ul>
<li>Ability to specify a different language for each widget/shortcode.</li>
<li>Locations all over the world.</li>
<li>Tons of options and configurations including: colors, layouts, formats, and many more.</li>
</ul>
Speed load impact:
<ul>
<li>Only a CSS file will be loaded, no JS on the front-end.</li>
<li>Images are loaded from the tiempo.com static file CDN server.</li>
<li>Internal file caching.</li>
</ul>
Important: In order to mitigate the site speed impact, please make sure to set write permissions to the <code>tiempocom/cache</code> directory. The plugin performs an intelligent expiry time management to ensure you have always the data up to date.
Supported languages:
<ul>
<li>English</li>
<li>Spanish (Spain)</li>
<li>German</li>
<li>Catalan</li>
<li>French</li>
<li>Italian</li>
<li>Portuguese</li>
<li>Euskera</li>
<li>Galician</li>
</ul>

Tiempo.com

Tiempo.com for WordPress. Allows to add weather widgets and shortcodes from the tiempo.com API.

Weather Widget by Calcatraz vs Tiempo.com