Overall, the lunar night temperature difference was around 8–10 Kelvin. …

The reason for the dip, according to the team, is the amount of radiation received from the Earth. During the lunar night on the near side, the Moon receives its radiation as it is reflected off the surface of the Earth. As human activities changed, and fewer pollutants were put into our atmosphere, this had a knock-on effect, with less radiation reflected toward the Moon. And so, COVID-19 lockdowns appear to have, inadvertently, briefly made the surface of the Moon colder.