2 sentences

1. 秋风习习，天气转凉了。

   qiū​fēng xí​xí, tiān​qì zhuǎn​liáng le.

   With the gentle autumn breeze, the weather is turning cool.

   Source: Dong Chinese Dictionary

2. 由于天气转凉，感冒的人数开始增多。

   yóu​yú tiān​qì zhuǎn​liáng, gǎn​mào de rén​shù kāi​shǐ zēng​duō.

   As the weather gets cooler, the number of people with colds is starting to increase.

   Source: Dong Chinese Dictionary