What is the best time to send an email newsletter?

Statistically speaking, you should avoid sending your newsletter mid-week or in the afternoon. Open rates are up to 1.5 times lower than on Mondays, Fridays or weekends. The best time to send an email campaign is between 8 and 11am, or evenings between 6 and 9pm. 

In the B2C sector, it also makes sense to send emails at the weekend. Early afternoon tends to yield the best open and click rates. 

Of course, these figures are just a general guideline. Each group of recipients has their own preferences, so it's important to experiment in order to find the optimal send-time for your audience.