Answer:
The temperature increase went down because it became cooler as the sun went down for the night.
Explanation:
The most appropriate answer will be,
The temperature increase went down because it became cooler as the sun went down for the night.
We know that it is the hottest of the day at the noon and thereafter the temperature decreases steadily becoming the coolest at night. Thereafter, the temperature starts to increase at the morning becoming again hottest of the day at noon.