Mars doesn't have the same calendar as Earth, so there's no direct equivalent to "December."

However, Mars' average temperature varies significantly throughout its year, which is about 687 Earth days long.

Here's what you can expect:

* Average temperature on Mars: Around -63°C (-81°F)

* Summer temperatures: Can reach up to 20°C (68°F) at the equator during the day

* Winter temperatures: Can drop to -143°C (-225°F) at the poles

Important note: These are just averages. The actual temperature on Mars can vary greatly depending on the location, time of day, and season.