Email marketing messages sent out on Mondays generate the highest revenue per mail, according to a recent study from Experian CheetahMail. The report also explained that emails sent on Friday had the highest click rates. According to the report, the best time and day to mail can vary by industry. However, emails sent on Saturdays and Sundays had the highest open and click rates, and the highest transaction rates, across the industry. Yet, email marketers sent their lowest volume of emails over the weekend.