This is the 2746th most frequent German word.
kalte
"Cold."
Here, 'kalte' is an adjective describing the noun 'Luft' (air), indicating its temperature.
Die kalte Luft strömt durch das Fenster.
The cold air is flowing through the window.
In this sentence, 'kalte' modifies the noun 'Tage' (days), emphasizing the characteristic temperature of those days.
Im Winter mag ich besonders kalte Tage, weil ich gerne Ski fahre.
In winter, I especially like cold days because I enjoy skiing.
Here, 'kalter' (the declined form for the feminine dative 'Höflichkeit') conveys a figurative meaning of emotional coldness rather than physical temperature.