Data-linked mosaic NEXRAD images can be more than 14 minutes old by the time they reach the cockpit for use by pilots (Elgin & Thomas, 2004; Novacek et al., 2001; Yuchnovicz et al., 2001). Unfortunately, research has indicated that pilots may not be fully aware of the delay (Yuchnovicz etc., 2001) and that it can adversely affect their decision-making and performance (Chamberlain & Latorella, 2001). The experiment reported here evaluated the effects of three types of timestamp representation methodologies on participant’s accuracy for quick assessments of delay of NEXRAD mosaic radar images. The three types of timestamps investigated were “direct age”, “clock” and “UTC” with three levels of delay (short, medium and long). Twenty-one participants compared two radar images, via their timestamps, to determine which one was more recent. The results indicated that “direct age” timestamp resulted in the highest accuracy and fastest response time, and was considered as intuitive and easy to perceive for participants.