"Getting colder" or "Becoming colder".
This phrase comes from the common understanding that temperature can change and decrease over time, resulting in a "colder" environment.
Example sentence in Engpsh:
"As the night falls, the temperature is getting colder."
"The weather is becoming colder, make sure to wear warm clothes."
中文翻译：
"随着夜幕降临，气温越来越冷。"
"天气变冷了，记得穿保暖的衣服。"