<p>Global temperature has increased at a rapid rate in recent decades, and the warming rate at night is observed higher than that during the daytime among different regions. Nighttime anomalous high temperatures may pose an additional risk to human health and society. Nevertheless, less research has explored the spatiotemporal trend and the local atmospheric mechanism of nocturnal temperature anomaly around the world. Here, we investigate the spatiotemporal trend of nighttime temperature anomaly (NTA) from 1961 to 2023, and analyze the underlying physical mechanism related to different extents of positive temperature anomaly. We find that NTA showed a significantly increased trend worldwide, with an increasing rate of 0.21°C/decade. At the continental scale, NTA has increased faster in North America, Asia, and Europe. The occurrence of positive NTA is generally associated with local increased cloud cover, precipitation, and humidity, which contribute to enhanced downward longwave radiation and greenhouse effect at night. On the inter-annual scale, NTA is positively related to the preceding winter Oceanic Niño Index, indicating the possible modulation of El Niño-Southern Oscillation on the global nocturnal temperature. Our results could help to understand the variation and influence mechanism of anomalous nighttime temperature in recent decades, and inform the forecast of and response to hot nights.</p>