How does the lunar surface change temperature during a lunar eclipse?

During a lunar eclipse, the lunar surface undergoes rapid cooling as the Sun’s radiation is suddenly removed by Earth’s shadow.12

The rate of this cooling is not uniform across the surface; it depends on the constitution and heat conductivity of the lunar soil. Observations show that the surface cools unevenly, with some areas—particularly near relatively young craters—retaining heat longer than their surroundings. This variation is often attributed to differences in the heat conductivity of the lunar material, though the exact causes for some of these "bright spots" in infrared radiation remain a subject of scientific study.123

Because the lunar regolith acts as an efficient insulator, the cooling effect is primarily restricted to the uppermost layers of the surface. Measurements of infrared and radio-wavelength radiation during an eclipse have allowed astronomers to study these thermal properties, confirming that the highly insulating layer of the Moon is relatively shallow.32