• by Gavin O'Malley  @mp_gavin, August 11, 2015

That’s according to new research from mobile marketing agency Fetch, which based the conclusion on an analysis of more than 12 billion data points across 100 countries.

In January, for instance, many people are still getting familiar with the phones they were gifted over the holidays. This means they’re most likely exploring and downloading a ton of apps.

By February, however, a far more regular mobile engagement pattern is established, according to Dan Wilson, head of data at Fetch.

The problem is that “most marketers don’t change the way they plan and buy media during the period from January to February,” Wilson writes in the new report. “They need to change their approach as these are two distinctly different months from a consumer acquisition perspective.”

During the summer, expensive quality-driven inventory and cheaper user-acquisition inventory is more common, Fetch finds.

Due to less mobile engagement during this time period, there is a smaller pool of consumers to choose from, which means obtaining users through incentivized campaigns becomes more difficult. As a result, both the demand and price of inventory falls, according to Wilson.

More expensive weeks tend to have a build-up time, which creating expensive “periods” -- as opposed to singular expensive weeks.

When analyzing cheaper summer months from the data it gathered, Fetch also found that weeks at the start of these months are relatively more expensive than those at the end -- but this is not a trend that is consistent in more expensive months.

On a weekly basis, effective cost per app install (eCPI) rate trends across incentivized and non-incentivized campaigns follow similar patterns, according to Fetch’s findings.

Wilson and his colleagues say this trend may be attributable to the IO (insertion order) structure of mobile media buying. IOs signed at the start of the month take effect mid-month, which leads to an uptake in inventory, and therefore eCPI.

As budgets dwindle at the end of a month, the demand for inventory begins to fall, yielding below-average eCPI for these weeks, Wilson and his team surmise.