The weather is getting cold in Vietnam, especially in Hanoi. We have to prepare enough warm clothes before Tet. Temperatures right below 9 degrees Celsius (°C) are really cold for us but it is said that it only feels cool to/for some foreigners.

Brrrrr! It's getting cold in Vietnam, especially in Hanoi. We need to have plenty of warm clothes on display in the store for our customers before Tet. We say 9°C is cold, but to some foreigners that sounds like a joke. I was confused by your second sentence. I am guessing you meant that you need to have clothes ready in your store to sell to customers.

The weather is getting cold in Vietnam, especially in Hanoi. We have to prepare warm clothes enough before Tet. It is really cold: just under 9 degrees for us, but it is said that it just feels cool to some foreigners.