Moon · Golden hour · Dark sky

Know which nights are worth the drive.

Sky Window works out sunset, golden and blue hour, the moon, and the truly dark hours for any place, then puts the best nights of the month on one calendar.

Free. Runs in your browser. No account.

How it works

Three choices. Then the sky does the maths.

  1. 01

    Pick a place.

    Search 130 towns and dark-sky parks, use where you're standing, or type exact coordinates.

  2. 02

    Pick your dates.

    The next 30 nights are chosen for you. Stretch the range to any 92.

  3. 03

    Read the calendar.

    Every night shows its moon and its moonless dark time. The best three get a star.

One night at Kielder Forest

Watch a night unfold.

Sky Window samples the sky every five minutes from noon to noon, then pins each edge to the second.

Thu 12 Nov 2026 · the best night of the month

  1. 16:12 Sunset The sun's centre slips below the horizon.
  2. 16:37 Evening golden hour ends The sun passes −4° and the warm light goes.
  3. 16:52 Blue hour ends The sun passes −6°. The blue drains out of the sky.
  4. 17:21 Moonset The waxing crescent, 13% lit, follows the sun down.
  5. 18:19 Astronomical dusk: dark begins The sun passes −18°. The sky is as dark as it gets.
  6. 11h 11m Moonless dark 18:19–05:30. Sun 18° down, moon below the horizon. This is the window.
  7. 05:30 Astronomical dawn The sun climbs back past −18°. The faintest stars go first.
  8. 07:38 Sunrise Friday begins. The night is over.

What it knows

Everything between sunset and sunrise.

November 2026 · Kielder Forest

  1. 1 3h 34mGood
  2. 2 5h 12mExcellent
  3. 3 6h 45mExcellent
  4. 4 8h 14mExcellent
  5. 5 9h 41mExcellent
  6. 6 10h 52mExcellent
  7. 7 10h 55mExcellent
  8. 8 10h 58mExcellent
  9. 9 11h 1mExcellent
  10. 10 11h 5mExcellent
  11. 11★ 11h 8mExcellent
  12. 12★ 11h 11mExcellent
  13. 13★ 11h 6mExcellent
  14. 14 9h 53mExcellent
  15. 15 8h 35mExcellent
  16. 16 7h 17mExcellent
  17. 17 5h 59mExcellent
  18. 18 4h 40mGood
  19. 19 3h 21mGood
  20. 20 1h 59mFair
  21. 21 32mPoor
  22. 22 0mNone
  23. 23 0mNone
  24. 24 0mNone
  25. 25 0mNone
  26. 26 0mNone
  27. 27 5mPoor
  28. 28 1h 41mFair
  29. 29 3h 19mGood
  30. 30 4h 53mGood
  • Excellent
  • Good
  • Fair
  • Poor
  • None

A calendar ranked for darkness.

Each night carries its moon phase and how long the sky is truly dark with the moon down. Colours rate it from Excellent to None, always with the word beside the colour.

Thu 12 Nov · Kielder Forest

Morning

06:5607:1108:36

Blue hour 06:56–07:11, golden hour 07:11–08:36.

Evening

15:1216:3716:52

Golden hour 15:12–16:37, blue hour 16:37–16:52.

Sunset 16:12 · Sunrise 07:38

Golden and blue hour, both ends of the day.

Morning and evening golden hour from −4° to +6°, blue hour from −6° to −4°, in the place's own time zone.

Kielder, 55° N
Lake Tekapo, 44° S

The moon as you'll see it.

Phase name and percent lit for every night, drawn the right way round in the southern hemisphere too.

Night vision.

A red-on-black theme with no blue light, so checking the time doesn't cost you your dark adaptation.

None 0m

Honest at the poles.

In Tromsø in June there's no dark at all, and Sky Window says so: 'Sun stays up all day', never a made-up time.

Yours, and offline.

No account, no server, no tracking. Your places and theme stay in your browser, and the planner keeps working with no signal at the trailhead.

  • No account
  • Works with no signal
  • Places saved in your browser

The planner itself

Don't take the page's word for it. Try it.

This is the planner itself, running right here. Type Kielder in the search, or any town you know.

Opens full screen too: open the planner in its own tab ↗

The fine print

Worked out, not guessed.

Sun and moon positions come from published astronomical formulas, computed on your device. Sun times land within about two minutes of almanac tables.

Sunrise and sunset
the sun's centre crosses −0.833°.
Golden hour
sun from −4° to +6°.
Blue hour
sun from −6° to −4°.
Dark sky
sun below −18° (astronomical night).
Moon up
moon at or above +0.125°.
A night
local noon to local noon, named for the evening's date.

The next dark night is already on the calendar.

Open the planner

Free · In your browser · Works offline