[cmhamill]

Do you make API calls, or just grab web pages? I've noticed the Google APIs seem to occasionally return errors for no apparent reason. You could try double-trying in your Nagios check.

It's also complicated by Google's infrastructure — services are scattered across many, many servers, and Google's outages tend to be on some subset of services and/or servers. Your Nagios checks are probably not always checking the same endpoint as users connecting.