天气很好。
Tiānqì hěn hǎo
Weather very good.
The most classic phrase
今天天气很好，适合出门走走。
Jīn tiān tiānqì hěn hǎo, shìhé chū mén zǒu zǒu
Today weather very good, suitable for going out for a stroll.
走走 = take a stroll
风和日丽，正是出游的好时节！
Fēng hé rì lì, zhèng shì chū yóu de hǎo shí jié!
Wind gentle sun beautiful, this is the perfect season for an outing!
风和日丽 = classic 4-character idiom for perfect gentle weather
More Chinese (Mandarin) Weather Phrases