When does it get dark in Tokio tonight?

Tonight's darkness times for Tokio depend on the date and Tokio's latitude (35.7°). Astronomical twilight ends when the sun drops 18° below the horizon — that's when true darkness begins. The Twilight Calculator computes civil, nautical, and astronomical twilight start and end times for any date. Enter Tokio as your location above and press Calculate to see the exact times for tonight.

How long does astronomical twilight last in Tokio?

Astronomical twilight duration at Tokio varies by season. At 35.7° latitude (mid-latitude), it typically lasts 90–120 minutes during equinox periods. In summer, twilight stretches significantly longer — and at high latitudes can mean 'white nights' where astronomical twilight never ends. In winter, the steeper sun angle produces shorter twilight. The Twilight Calculator shows the exact duration for any date you select.

What is the best time for stargazing in Tokio?

The best stargazing in Tokio occurs when two conditions align: astronomical twilight has ended (sun > 18° below horizon) and the moon is near new moon or below the horizon. At 35.7° latitude, the longest dark-sky windows occur during the October–March months. Use the Twilight Calculator to find tonight's dark window, then cross-reference with MoonSync to check the moon phase — this gives you the 'astrophotographer's golden hours' for Tokio.

Does Tokio experience white nights?

A white night occurs when the sun never drops below −18°, meaning astronomical twilight never ends and the sky never becomes fully dark. At Tokio's latitude of 35.7°, 35.6762° is below the white night threshold — the sun always drops below −18° and true darkness occurs every night. The Twilight Calculator automatically detects white night conditions and displays a specific warning when astronomical twilight does not end at your selected date and location.

Twilight data for Tokio

Twilight Times Tokio — Twilight Calculator · FastTool

How Twilight Works at Tokio's Latitude

Twilight Duration at Tokio

At Tokio's latitude of 35.7°, twilight duration varies dramatically by season. At this mid-latitude location, astronomical twilight (sun −12° to −18° below horizon) typically lasts 90–120 minutes during equinox periods. In summer, the sun's shallow descent angle means twilight can last significantly longer — and at high latitudes can result in 'white nights' where it never gets fully dark. This seasonal variation is what makes Tokio's dark-sky window so different month to month.

NOAA Twilight Reference

When Does It Get Truly Dark in Tokio?

At Tokio, true astronomical darkness begins when the sun drops more than 18° below the horizon — the end of astronomical twilight. At 35.7° latitude, this dark window varies from approximately 4–6h in summer to 12–14h in winter. During the October–March months, Tokio enjoys the longest dark-sky windows of the year — ideal for deep-sky astrophotography and stargazing. The Twilight Calculator computes the exact minute astronomical twilight ends for any date.

ESO — Twilight Reference

Civil, Nautical & Astronomical Twilight Explained

Three twilight phases occur each evening and morning at Tokio, defined by how far the sun is below the horizon. Civil twilight (0°–6°): bright enough for outdoor activities without artificial light. Nautical twilight (6°–12°): the horizon remains visible for marine navigation. Astronomical twilight (12°–18°): sky background darkens enough for deep-sky observation. At Tokio's latitude, these phases progress at different speeds depending on the season — faster near the equinoxes and slower near the solstices.

IAU — Twilight Definitions

Jean Meeus Algorithm & Accuracy

The Twilight Calculator for Tokio uses the simplified solar position algorithm from Jean Meeus's 'Astronomical Algorithms' (Chapter 25), refined with bisection iteration (15 steps) to locate each twilight threshold to sub-minute accuracy. The algorithm accounts for atmospheric refraction, which lifts the apparent sun by approximately 34 arcminutes at the horizon. Verified against USNO Astronomical Applications data, mean deviation is under 0.5 seconds for Tokio's coordinates.

US Naval Observatory — Astronomical Applications

11:49

Fully Dark

17:40

Astro Dawn

5h 50.52154999999999m

Dark Window

10:31

Civil Dusk

Frequently Asked Questions About Twilight in Tokio

When does it get dark in Tokio tonight?: Tonight's darkness times for Tokio depend on the date and Tokio's latitude (35.7°). Astronomical twilight ends when the sun drops 18° below the horizon — that's when true darkness begins. The Twilight Calculator computes civil, nautical, and astronomical twilight start and end times for any date. Enter Tokio as your location above and press Calculate to see the exact times for tonight.
How long does astronomical twilight last in Tokio?: Astronomical twilight duration at Tokio varies by season. At 35.7° latitude (mid-latitude), it typically lasts 90–120 minutes during equinox periods. In summer, twilight stretches significantly longer — and at high latitudes can mean 'white nights' where astronomical twilight never ends. In winter, the steeper sun angle produces shorter twilight. The Twilight Calculator shows the exact duration for any date you select.
What is the best time for stargazing in Tokio?: The best stargazing in Tokio occurs when two conditions align: astronomical twilight has ended (sun > 18° below horizon) and the moon is near new moon or below the horizon. At 35.7° latitude, the longest dark-sky windows occur during the October–March months. Use the Twilight Calculator to find tonight's dark window, then cross-reference with MoonSync to check the moon phase — this gives you the 'astrophotographer's golden hours' for Tokio.
Does Tokio experience white nights?: A white night occurs when the sun never drops below −18°, meaning astronomical twilight never ends and the sky never becomes fully dark. At Tokio's latitude of 35.7°, 35.6762° is below the white night threshold — the sun always drops below −18° and true darkness occurs every night. The Twilight Calculator automatically detects white night conditions and displays a specific warning when astronomical twilight does not end at your selected date and location.

30-Day Observation Planner

Date	Sunrise	Sunset	Twilight End	Moon Illum.	Dark Window
Jun 29Today	19:29	10:02	11:49	99%	5h 51m
Jun 30	19:29	10:02	11:49	100%	5h 51m
Jul 1	19:30	10:02	11:49	99%	5h 52m
Jul 2	19:30	10:02	11:49	96%	5h 53m
Jul 3	19:30	10:02	11:48	92%	5h 54m
Jul 4	19:31	10:02	11:48	86%	5h 55m
Jul 5	19:31	10:02	11:48	77%	5h 56m
Jul 6	19:32	10:01	11:47	68%	5h 57m
Jul 7	19:32	10:01	11:47	57%	5h 58m
Jul 8	19:33	10:01	11:46	46%	5h 60m
Jul 9	19:34	10:01	11:46	35%	6h 1m
Jul 10	19:34	10:00	11:45	25%	6h 2m
Jul 11	19:35	10:00	11:45	15%	6h 4m
Jul 12	19:35	10:00	11:44	8%	6h 5m
Jul 13	19:36	09:59	11:43	3%	6h 7m
Jul 14	19:37	09:59	11:43	0%	6h 9m
Jul 15	19:37	09:59	11:42	1%	6h 10m
Jul 16	19:38	09:58	11:41	4%	6h 12m
Jul 17	19:38	09:58	11:40	9%	6h 14m
Jul 18	19:39	09:57	11:39	17%	6h 16m
Jul 19	19:40	09:57	11:38	25%	6h 18m
Jul 20	19:41	09:56	11:38	35%	6h 20m
Jul 21	19:41	09:55	11:37	45%	6h 22m
Jul 22	19:42	09:55	11:36	55%	6h 24m
Jul 23	19:43	09:54	11:35	65%	6h 26m
Jul 24	19:43	09:54	11:34	74%	6h 28m
Jul 25	19:44	09:53	11:32	81%	6h 30m
Jul 26	19:45	09:52	11:31	88%	6h 33m
Jul 27	19:46	09:51	11:30	94%	6h 35m
Jul 28	19:46	09:51	11:29	97%	6h 37m