[jeffbee]

Of course, but that doesn't really excuse them. My first experience with middle-of-Sunday-night SSL certificate expiration was in December 1998, and it was already a well-known doctrine by then. I'd expect a commercial certificate authority to have these kinds of things squared away.

[user5994461]

My experience with commercial CA is that they set the expiry exactly 1 year from creation. Doesn't matter if it's a week end or a holiday.

[sjtindell]

Generally that’s for Server certs, Roots and Intermediates will be multiple years from what I’ve seen. Roots in particular 10+ years.

[abiogenesis]

1 Year is a relatively recent thing. Previously you were able to buy server certs with a 5 year expiration.