Planned downtime for any website is very common, but it is good to always notify visitors about it. While it is not necessary, it tells visitors that your website has not just vanished into thin air. It is in bad taste to give visitors a 404 page when they visit your URL.
When I plan a site downtime, I use HTTP 503 result code, which is specifically meant for sites on downtime. To keep your visitors in good humor, use some funny clip art to send across the message. The 503 code also helps search engines know that they don’t need to downgrade your ranking.
