Katrineholm
PEAK
Poor tonight
Hour by hour, local to Katrineholm. Colour encodes the score and nothing else; every other measurement is luminance.
Cloud tracks show clear sky — a longer bar is better. The figure inside each track is the raw measurement.
Astronomical darkness begins when the sun is 18° below the horizon. Above that, there is still measurable skyglow, and faint deep-sky work is compromised even though the sky looks black.
What are you doing tonight?
The same forecast, weighted for the target. Planetary work barely cares about moonlight; long exposures die on high cloud a visual observer would never notice.
Darkness and moonlight dominate. Faint fuzzies need a genuinely dark sky more than they need steady air.
Seeing is everything and moonlight is irrelevant. Bright targets punch through twilight, so darkness barely counts.
Tolerates soft seeing, but high cloud wrecks a wide frame and moonlight raises the background everywhere.
Needs conditions to hold still for hours. Sustained transparency matters more than any single good hour.
Naked eye, whole sky. Total cloud and moonlight are the only things that count.
The next week of nights
01:00–02:00
02:00–03:00
02:00–03:00
Nearby locations
About this forecast
Conditions for Katrineholm, Sweden are computed from the MET Norway forecast model for these exact coordinates, combined with sun and moon positions we calculate directly. The score weighs cloud cover by layer, atmospheric transparency, estimated seeing, moonlight and how dark the sky actually gets. Read the full method →