Here's a template install script for ya Madhouse.

Just upload it to your admin directory and run it from your browser.
Before you run the script, check to see if your mYvBindex options in your Admin CP has an option to turn the weather on (it should be the 3rd from the last option). If not, run step 3 of this installer (where it asks if you want to log into your Admin CP or add the option to show the weather). If you already have the weather button under your options you can skip that step and just log into your Admin CP.