In Website Magazine's article "Google: Site Speed a Ranking Factor", they mentioned site speed is definitely a ranking factor for search engines. It doesn't carry as much weight as keywords or page relevance, but it does affect ratings. Our world is starting to get used to having information right here and right now. If a page takes too long to load, they don't want to waste their time on it. They will try to find another site with relevant information and less load time.
I found the graphics below on Google Analytics' Blog. It is very helpful to see site speed laid out in graphs. If your site speed has a very high average, it may not be the user's Internet connection, but your website. Large graphics and high quality videos are a few things that increase load time. Google also stated that site redirects are factored in page load time.
|A Google Analytics graph displaying the page load times in seconds.|
|Another Google Analytics graph of page load time by percentage.|
|The map feature in Google Analytics can come in handy if you are trying to reach a specific country or continent.|