After losing $16 billion last year, the postmaster general announced Wednesday that the Postal Service intends to halt Saturday delivery of first-class mail by this summer. That means most mailers, letters and catalogs would not arrive on Saturdays, ending a 150-year tradition.

I think that sucks, but there is an enormous budget deficit (imagine that) that the USPS needs to close. This is their best idea at the moment and one that President Obama has been pushing for quite some time. With physical mail being halted on Saturdays this got me thinking about the best times to send emails in the world of B2B marketing, and if weekends are indeed a good time to do so. It may be a stretch, but this is the type of thing I think about all day.

The notion of whether or not to email on the weekend was top of mind for me as I recently debated the topic on Twitter. Mike Volpe chimed in on the conversation with a link to the Science of Email Marketing presentation. I retorted with a heat map showing email open rates by day of the week for all emails sent out by Marketo’s demand gen team last quarter. How’s that for the power of revenue cycle analytics? Something that no other marketing automation provider can do by the way.

There’s a ton of info out there regarding the best day and time to send an email and in many cases the data is all over the place. Many believe sending email on Tuesday is optimal and Friday is the worst. There are also those who believe that sending emails on the weekend when there tends to be less volume helps increase open rates. What’s the correct answer? To be honest, there really isn’t one. To ensure optimal results, you simply have to test, test, test, then test some more.

The fact is that in 2013 it’s a whole new ball game. Many people check work emails on their mobile phones and are no longer tied to office hours. Since they have their phones with them all the time, Fridays or the weekend could be a great time to reach the constant email checker who is bored on a bus or on a train, or simply checking their messages before throwing in the towel for the week. As I mentioned previously, below is the heat map showing open rates for emails from Saturday to Sunday. Red signifies the worst times to send emails and green shows the best.

The bottom line is, neither snow nor rain nor heat nor gloom of night should stray your company from experimenting with sending out email campaigns on Saturdays or Sundays. In the end, the best way to find out is to A/B test, review performance stats, iterate, and repeat. Who knows for sure, but after August 1st your customers and prospects might have more time in their weekends to open up your company’s mail.