Pure360, an email marketing solution, recently revised a 2011 white paper on the best (and worst) times to send an email newsletter.

Some of Pure360′s research confirmed what web marketers knew all along, like overnight emails (between midnight and 7 a.m.) perform very poorly. But digging through the white paper lead to a few tidbits that might not be so well-known.

Here are some interesting findings from the white paper:

Two times of day, 10 a.m. to noon and 5 p.m. to 7 p.m. are typically the most ideal times of day to send your email newsletter, especially if you are a B2C company. Pure360 claims that some 26 percent of all marketing emails sent between 5-7 p.m. are opened. That’s up from the approximately 17 percent of emails that are opened. The rule of thumb, then, should be to avoid sending newsletters past midnight and before 7 a.m.

Autumn is the best time of the year to begin a new campaign. Pure360′s research suggests that 21 percent of all emails sent in Sept. and Nov. are opened, compared to a 17 percent average during the remainder of the year. Pure360 postulates that the increase in open rates has to do with families being home after Summer breaks and vacations.

Abi Jacks,  head of marketing at Pure360, commented about the findings in the white paper.

“It’s easy to make assumptions about consumer behaviour and many marketers believe that sending emails first thing in the morning benefits their open rates,” Jacks.

“But in fact, our research shows that they need to really get to know their sector audience and be aware of unexpected trends – such as the habit people have for opening emails that they receive as the time-pressures of the work day ease off on the commute home.”

The white paper has a bit more information, including a breakdown of the best time to send an email newsletter by industry, which is particularly interesting. Click here to download.