It is common for schools have a direct link to their related alumni associations on their websites. These associations organize and promote official class reunions. There are also independent websites such as Classreport.org and Alumniclass.com that provide platforms for class reunion groups to share information.
Any high school or college should have an alumni association. If there is not a direct link on the school's website, contact the school for information by phone or email. The alumni association usually has a mailing list or newsletter for which former students can sign up, which contains information about any planned class reunions. Alumni sometimes form groups on social networking sites such as Facebook to keep in touch, and reunion information is often available within these forums.
Websites that host alumni groups commonly have an easy-to-use searchable database to find the interested individual's school and graduating class. Not all schools have a presence on these websites.
The best time to search for news of a class reunion is around the five- to 10-year anniversaries in the years following graduation, around the date of the commencement ceremony. Some alumni groups begin planning these reunions years beforehand, due to the difficulty of finding past classmates and making arrangements.