There are three seasons in Thailand:
Hot Season or rɯ́-duu rɔ́ɔn (ฤดูร้อน),
Cold Season or rɯ́-duu nǎaw (ฤดูหนาว),
Rainy Season or rɯ́-duu fǒn (ฤดูฝน).
The word rɯ́-duu (ฤดู) means “season”; you also can use nâa (หน้า) in spoken (as opposed to written) Thai. When talking about the rainy season, for example, we would use rɯ́-duu fǒn(ฤดูฝน) or nâa-fǒn (หน้าฝน).
The word “flood” in Thai is náam-thûam (น้ำท่วม): náam (น้ำ) means “water” and thûam (ท่วม) means to overflow, so “flooding” isnáam-thûam (น้ำท่วม) and “not flooding” is náam mâi thûam (น้ำไม่ท่วม).
To say mâi náam-thûam (ไม่น้ำท่วม) would be incorrect because you can’t put mâi (ไม่) before nouns and the word náam (น้ำ) is a noun.
In the same way, “it is raining” or “it rains” is fǒn-dtòk (ฝนตก), where fǒn (ฝน) means “rain” and dtòk (ตก) means “to fall”. “It’s not raining” or “no rain” is likewise rendered as fǒn mâi dtòk (ฝนไม่ตก), not mâi fǒn-dtòk (ไม่ฝนตก).