The temperature on Mars can drop to minus 100 degrees F (minus 73 degrees C). In today's "You ask, we answer" rubric we are answering your further questions about Mars's in-game temperature.
Will it be possible to build at night or will we freeze?
You can build at night but you have to keep an eye on your colonist's temperature. This is where different suits and equipment will come into play. For Mars1, this mechanic will not be included, but the full character systems such as upgrades and equipment will be featured in later versions of the game. Mars1 is the first playable version of Mars coming out in 2022 Q2.