I was settling down for a holiday week filled with family, food and friends when I started reading whispers of a major Google algorithm update on Twitter and elsewhere. Launching an algorithm update just before a major holiday would make sense for Google. For one, it’s a lot harder to detect and discern an update when traffic levels are mostly dropping or fluctuating wildly this time of year. Two, SEOs with lives outside of the office wouldn’t be around to give them grief if sites started dropping.

I wanted to see if Google has any sort of history of launching updated on a particular day or time. For the reasons outlined above, it would make sense for Google to be strategic about when launching major updates to their search algorithm. If they really wanted to punish link spam, for example, they could take aggressive action shortly before the major shopping season in November & December. Aggressive spammers who were penalized wouldn’t have a chance to recover.

Up until a few years ago, it has been hard to nail down exact dates for algorithm releases. Throughout most of their history, Google has released ‘monthly’ updates that included a number of changes and tweaks. Since 2011, however, we have pretty accurate data of Google-confirmed algorithm updates.

I moved them all into a spreadsheet and here’s what patterns emerged:

Some quick observations:

– The strongest tendency appears to be releasing updates closer to the end of the month. Out of the 38 confirmed updates I listed, 30 of them occurred on or after the 15th of each month.

– Friday is the most popular day to release an update. Not surprising, given that it can take until Tuesday or Wednesday for webmasters to figure out if anything has changed. This gives Google a few days of cushion to make any extra changes.

– Surprisingly, algorithm updates were also very common early in the week. Monday and Tuesday have been release days for 7 updates each.

– Given Google’s past release dates, I’ll predict that Friday, March 21, 2014 will be the next major update. This ticks the boxes for most popular day (Friday) and date (21st). There isn’t a noticeable correlation between algorithm updates and month…though spring tends to be a common season for major updates.

This is terribly unscientific but something fun to think about when looking at Google’s past and thinking about the timeline for future releases.