How to use these 2 words? Thanks

How to use these 2 words? Thanks

Lexitron shows the two as synonyms:

ฤดูหนาว [rí-doo năao ] [N] winter

Class. ฤดู

Syn. หน้าหนาว [nâa năao]

Sample:เมื่อถึงฤดูหนาวนกนางนวลแกลบจะพากันบินจากขั้วโลกเหนือ เพื่ออพยพลงไปอยู่ที่ขั้วโลกใต้

"When winter comes, the term will flock from the North Pole to sojourn at the South Pole."

The book คลังคำ implies that the word ฤดู is an "official" word where as, by implication, the word หน้า is more colloquial.

The book คลังคำ implies that the word ฤดู is an "official" word where as, by implication, the word หน้า is more colloquial.

Rings true with me; people tend to use mostly หน้า in conversation, whereas ฤดู is higher register, which you might see in more formal texts or in speeches or newscasts. (This is not an absolute rule, there is some overlap too).