Astronomers are not only interested in the stars and the planets, but also the weather. We can only observe the wonders on the night sky if it is clear. Also, if we seek dim objects like distant galaxies we need the moon to not be in the sky. Did you every wonder why stars twinkle? They twinkle because the turbulence of the air above you is pushing and shoving the light around so we also care about the overall turbulence. Finally, moisture in the air, that is not quite a cloud will absorb light and ruin a good night. In the end we look for 4 forecasts:
- Cloud cover
There are some special web sites that help us by making this information graphical and easy to understand at a glance.