Summary: As of mid-May 2018, Google has reverted back to shorter display snippets. Our data suggests these changes are widespread and that most meta descriptions are being cut off in the previous range of about 155–160 characters.
Back in December, Google made a significant shift in how they displayed search snippets, with our research showing many snippets over 300 characters. Over the weekend, they seem to have rolled back that change (Danny Sullivan partially confirmed this[1] on Twitter on May 14). Besides the obvious question — What are the new limits? — it may leave you wondering how to cope when the rules keep changing. None of us have a crystal ball, but I'm going to attempt to answer both questions based on what we know today.
Lies, dirty lies, and statistics...
I pulled all available search snippets from the MozCast 10K (page-1 Google results for 10,000 keywords), since that's a data set we collect daily and that has a rich history. There were 89,383 display snippets across that data set on the morning of May 15.
I could tell you that, across the entire data set, the minimum length was 6 characters, the maximum was 386, and the mean was about 159. That's not very useful, for a couple of reasons. First, telling you to write meta descriptions between 6–386 characters isn't exactly helpful advice. Second, we're dealing with a lot of extremes. For example, here's a snippet on a search for "USMC":
Marine Corps Community Services may be a wonderful organization, but I'm sorry to report that their meta description is, in fact, "apple" (Google appends the period out of, I assume, desperation). Here's a snippet for a search on the department store "Younkers":
Putting aside their serious