New research from GetResponse has found that an email's open rate is highest within the first hour of receipt. During this period messages in the study saw a 23% open rate. The emails remaining unopened in the inbox between one and two hours saw the open rate plummet to 9.5%, and during the next hour to 6.3%. The research also found that the most responsive send times were between 8am - 10am, and 3pm - 4pm.