Uptime is a critical factor for WordPress hosting. It refers to the uninterrupted accessibility of a website to users. A hosting provider that offers 99.9% uptime ensures that the website remains available for users 99.9% of the time. Maintaining a high uptime ratio is essential as it instils trust in visitors and encourages them to spend more time on your site. This, in turn, increases the potential for higher traffic, sales, and pageviews.