My Garmin weather shows incorrect location(Forerunner 255). I’ve tried with Phone location and with one pinned loc - same result. How it could be solved?

If you are using Garmin weather it usually uses a weather station at the nearest airport. What location does it say and is that your closest airport?

Not exactly. It shows just one small city in almost 100km away from airport. And I asked all my friends with different Garmin models - they don’t have such problem, only my device 

Where do you see the location? Is it in a 3rd party watchface or weather widget?

Is the standard Garmin weather widget showing a different weather?

If it is a 3rd party widget/watchface you are using you should talk to the developer. You can also post a link to what you are using and someone might be able to help you.