This is the 2416th most frequent Korean word.
기온이
"기온이" means "the temperature (subject marker attached)."
Here, '기온이' is used to refer to 'the temperature', specifically the air temperature of the environment, as a subject that is increasing.
기온이 점점 상승하고 있어요.
The temperature is gradually rising.
In this context, '기온이' signifies the air temperature as a subject and indicates its specific status as low for the day.
기온이 오늘은 매우 낮아요.
Today, the temperature is very low.
Here, '기온이' describes the air temperature's sudden change or drop, leading to colder conditions.