When does it get dark in レイキャビク tonight?

Tonight's darkness times for レイキャビク depend on the date and レイキャビク's latitude (64.1°). 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 レイキャビク as your location above and press Calculate to see the exact times for tonight.

How long does astronomical twilight last in レイキャビク?

Astronomical twilight duration at レイキャビク varies by season. At 64.1° latitude (polar), it typically lasts 3–6 hours or continuous 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 レイキャビク?

The best stargazing in レイキャビク 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 64.1° latitude, the longest dark-sky windows occur during the September–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 レイキャビク.

Does レイキャビク 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 レイキャビク's latitude of 64.1°, 64.1466° experiences extended white nights from May–August and may have midnight sun — the sun does not set during peak summer weeks. 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.

レイキャビクの薄明データ

レイキャビクの極域薄明時刻 — Twilight Calculator · FastTool

How Twilight Works at レイキャビク's Latitude

Twilight Duration at レイキャビク

At レイキャビク's latitude of 64.1°, twilight duration varies dramatically by season. At this polar location, astronomical twilight (sun −12° to −18° below horizon) typically lasts 3–6 hours or continuous 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 レイキャビク's dark-sky window so different month to month.

レイキャビクは2026年8月12日の皆既日食の皆既帯の真っ只中に位置します——中心線上にあるわずか2つの首都（グリーンランドのヌークと共に）の一つです。北緯64.1度では、この都市の極端な季節的薄明により、食の太陽はUTC約17:30に低く空に懸かり、アイスランドの火山景観を背景に永遠の夏の黄昏の中で日食を撮影する貴重な機会となります。

NOAA Twilight Reference

When Does It Get Truly Dark in レイキャビク?

At レイキャビク, true astronomical darkness begins when the sun drops more than 18° below the horizon — the end of astronomical twilight. At 64.1° latitude, this dark window varies from approximately 0 (white nights / midnight sun)h in summer to 16–20h in winter. During the September–March months, レイキャビク 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.

北緯64.1度のレイキャビクは世界最北の首都であり、5月下旬から8月上旬まで白夜を経験し、6月の夏至前後には市民薄明が一晩中続きます。この極端な緯度は、地球上で最も長い夏のゴールデンアワーを生み出します——太陽が完全に沈むことなく地平線をかすめる中、最大3時間にわたる柔らかな琥珀色の光が続きます。

ESO — Twilight Reference

Civil, Nautical & Astronomical Twilight Explained

Three twilight phases occur each evening and morning at レイキャビク, 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 レイキャビク'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 レイキャビク 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 レイキャビク's coordinates.

US Naval Observatory — Astronomical Applications

—

完全暗夜

—

天文薄明始

—

暗夜時間

—

市民薄明終

Frequently Asked Questions About Twilight in レイキャビク

When does it get dark in レイキャビク tonight?: Tonight's darkness times for レイキャビク depend on the date and レイキャビク's latitude (64.1°). 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 レイキャビク as your location above and press Calculate to see the exact times for tonight.
How long does astronomical twilight last in レイキャビク?: Astronomical twilight duration at レイキャビク varies by season. At 64.1° latitude (polar), it typically lasts 3–6 hours or continuous 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 レイキャビク?: The best stargazing in レイキャビク 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 64.1° latitude, the longest dark-sky windows occur during the September–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 レイキャビク.
Does レイキャビク 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 レイキャビク's latitude of 64.1°, 64.1466° experiences extended white nights from May–August and may have midnight sun — the sun does not set during peak summer weeks. 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日観測プランナー

日付	日の出	日の入り	薄明終了	月照度	暗夜窓
Jun 21本日	02:56	00:04	—	40%	—
Jun 22	02:56	00:05	—	50%	—
Jun 23	02:56	00:05	—	61%	—
Jun 24	02:57	00:05	—	70%	—
Jun 25	02:57	00:05	—	79%	—
Jun 26	02:58	00:04	—	86%	—
Jun 27	02:59	00:04	—	92%	—
Jun 28	03:00	00:03	—	96%	—
Jun 29	03:01	00:02	—	99%	—
Jun 30	03:03	00:01	—	100%	—
Jul 1	03:04	00:00	—	99%	—
Jul 2	03:06	23:58	—	96%	—
Jul 3	03:08	23:57	—	92%	—
Jul 4	03:10	23:55	—	86%	—
Jul 5	03:12	23:53	—	77%	—
Jul 6	03:14	23:51	—	68%	—
Jul 7	03:17	23:49	—	57%	—
Jul 8	03:19	23:47	—	46%	—
Jul 9	03:22	23:45	—	35%	—
Jul 10	03:24	23:43	—	25%	—
Jul 11	03:27	23:40	—	15%	—
Jul 12	03:30	23:38	—	8%	—
Jul 13	03:33	23:35	—	3%	—
Jul 14	03:35	23:33	—	0%	—
Jul 15	03:38	23:30	—	1%	—
Jul 16	03:41	23:27	—	4%	—
Jul 17	03:44	23:25	—	9%	—
Jul 18	03:47	23:22	—	17%	—
Jul 19	03:50	23:19	—	25%	—
Jul 20	03:53	23:16	—	35%	—

レイキャビクの薄明時刻 — Twilight Calculator · FastTool — 星空観測 — レイキャビク

ロンドンロンドンの薄明データベルリンベルリンの薄明データニューヨークニューヨークの薄明データ東京東京の薄明データパリパリの薄明データリスボンリスボンの薄明データ

レイキャビクの今日の市民薄明・航海薄明・天文薄明の時刻 — 天体写真のために真に暗くなる時間を確認。JPL DE440 ephemerisを使用した高精度計算。無料、プライバシー保護、アップロード不要。 · レイキャビクの薄明時間 — すべてブラウザ内で計算。ネットワーク通信ゼロ、位置情報送信ゼロ。