You are hereby informed that a large number of our company workers are going to take their days off due to extreme weather conditions prevailing in the city. Due to this, there would be much difficulty in coming and going so it is a mutual decision from the heads of our office to make it closed from 25-12-20XX to 02-01-20XX. This temporary closure will result in delayed answers to your queries, so these will be answered right after the opening of our office. All the delays are regretted.
Obviously, not every out-of-office is set for a vacation. You also need an out-of-office if you go on an extended business trip or to a conference. But instead of simply telling people you’re at a business event, why not use this opportunity to encourage networking of new business connections?

Proof that some people just Don’t Get It: in response to my out of office voicemail message directing callers to contact my co-worker for anything urgent, a woman left the following message on MY voicemail: “Co-worker, I am having this issue, blah, blah, blah. Please call me at X.” Yeah, I–not co-worker–got the message a week later when I returned.
There ought to be a word - and perhaps there is, in German - for the mix of feelings that accompanies composing and activating a holiday out-of-office message. There's smugness, of course, and a gratifying sense of laying down one's virtual tools after a horribly long shift. But for many of us, these nice feelings are tempered by the knowledge that in two weeks, refreshed but depressed, we will have to trawl through hundreds of emails, many of which will be conference room notifications for meetings about crises that have passed.