Sample Images using Spot Metering
If you simply switch to spot metering without further thinking the results get a matter of random.
In the picture frame used before the spot metering area would be where indicated on the right and mainly on the dark trees.
Consequently the picture will look a lot brighter because the camera will render this very dark piece of the picture with medium brightness:
With a very minor movement of the camera the result can look very differently. For the next sample I have lifted the camera slightly up and pressed the auto exposure lock button.
This has moved the area for spot metering as shown on the right, now it is just above the trees on the sky, including a small very bright area of the sky.
The picture will get a lot darker accordingly because now this relatively bright area will be darkened to medium brightness: