Email marketing is an old yet powerful tool for fostering e-commerce sales. As consumers are awash with email messages, it is important to find the perfect point in time to gain their attention and drive sales. Our study consists of an eight-month monitoring phase capturing transactional and interactional data of 129,937 consumers informing an online field experiment, with 12,948 customers exploring the effect of email timing on campaign performance measures. Consumers of the experimental group receiving timed emails according to online activity displayed significantly more unique visits, longer view times, and higher purchase amounts. Our findings add to the understanding of the importance of email timing and its impact on campaign performance—particularly in regard to actual sales numbers. From a managerial perspective, our findings suggest that campaign managers need to investigate consumers’ online activity to find the perfect point of time for email messages to increase the tool’s utility.