We report observations of waveforms in surface pressure made over several years by a network of ground‐level barometers in the eastern United States. The waveforms can be reconstructed by superimposing the 4th through 10th subharmonics of the solar day. Some of these solar harmonics are likely generated by the temperature and pressure gradients across the solar terminators. The measurements presented here enable a wave detection analysis which indicates that some waveforms are coherent between stations with a median speed of 49.7 m/s to the southeast. We interpret these propagating signals, which are interference patterns created by internal gravity waves with periods that are subharmonics of a solar day, as a previously undiscovered type of terminator wave. The waveforms appear predominantly postsunrise during winter and postsunset in summer. Their quasi‐eastward propagation direction suggests an analogy with “stern” waves left behind by the faster, westward‐moving terminator. Plain Language Summary The pressure of Earth's atmosphere at any point is a measure of the weight of the air above that location. Air pressure changes constantly due to many factors such as the weather and solar heating. Lesser‐known gravity waves (also known as buoyancy waves) play a key role in the dynamics of the atmosphere as their movement redistributes energy from one part of the atmosphere to another and temporarily changes air pressure locally. Air pressure measurements have been used for centuries to forecast weather conditions. In addition to practical interest, air pressure has also been the subject of much research over this time span as we seek a better understanding of how the dynamic atmosphere functions. In this paper, we present results from a new, large, network of pressure sensors in the United States which record air pressure continuously at many points. Gravity waves are observed that appear to be due to heating and cooling that occurs at sunrise and sunset. The waves, known as terminator waves, have never before been observed at Earth's surface. This is important because it provides further insight into how the atmosphere functions under the influence of the Sun. Key Points Surface pressure oscillations are observed in the 2 to 6‐hr passband in a temporal pattern that is linked with the solar terminator Array analysis reveals that most of these oscillations propagate with a median phase velocity of 49.7 ms−1 to the east‐southeast These signals are interpreted as evidence of a previously undiscovered type of terminator wave