This is correct: It was cold yesterday. I went swimming, though. remember that this is more informal. the formal and most correct way to write it is: Although it was cold yesterday, I (still) went swimming. we would usually only say it these ways: It was cold yesterday. I still went swimming though! Although it was cold yesterday. I still went swimming! Even though it was cold yesterday, I still went swimming.

Although it was cold yesterday, I still went swimming.