I just learned to play the violin. The weather is very cold these days, and the violin is seriously out of tune. I don't know how to turn around. Now I'm in the Pacific Ocean. I have no school. ...

Thermal expansion and cold contraction that have nothing to do with quality are common. . You should try not to make the change of hot and cold too obvious, such as turning on the air conditioner for a while and opening the window for a while.

There is no tuner, and the beep you hear when you pick up the phone is C.

If you really can't, buy an electronic tuner. It's convenient to have an indicator light ~