What is the average surface temperature of the earth's moon?
It's hard to say.
The Moon has about 13.5 days of daylight, followed by 13.5 days of darkness, so temperatures on the moon are extreme.
On the sunlit side of the Moon, the mean surface temperature is 107 °C, and the maximum temperature is 123 °C.
The "dark side of the Moon" has a mean surface temperature of -153 °C, with a minimum temperature of -233 °C.
There are craters around the north and south poles of the Moon that never see sunlight.
The temperatures in these craters range from -238 °C to -247 °C.
Similarly, there are nearby mountain peaks that are bathed in continuous sunlight, and these would always be hot.
You could take an average of the mean maxima and minima to get a mean surface temperature of -23 °C, but it wouldn't be very meaningful.