Is this the correct way to say it in Korean ?
The weather is cold so please wear warm clothes = 날씨가 추워서 따뜻한 옷을 입으세요.

Question

Is this the correct way to say it in Korean ? 
The weather is cold so please wear warm clothes = 날씨가 추워서 따뜻한 옷을 입으세요.

Answer

Almost.^^/
"날씨가 추우니까" sounds better.^^/

.........(으)니까......하세요
.........어/여/아/해+서......ㄹ 거예요/했어요
("...어/여/아/해+서...." doesn't go with imperative sentences or let's-sentences)

\^o^/