How many weeks are you when you are in your third trimester?

I believe it's 13.

Hiya, trimester one is from week one to week 13, trimester two is from week 14 to week 26 and trimester three is week 27 to 40 :-)

30 weeks is considered the beginning of the 3rd trimester. The second trimester ends at 28 weeks.

according to statistics, about 13 weeks.

13 weeks