節氣地球 Solar Terms & Seasons 二十四節気と地球
節氣不是民俗日子，是地球在軌道上的位置。拖著地球繞太陽走一圈，看四季怎麼來。 Each solar term is a place on Earth’s orbit. Drag the Earth around the Sun and watch the seasons happen. 二十四節気は、公転軌道上の地球の位置です。地球を太陽のまわりに動かして、季節が生まれるところを見てみましょう。
名詞小抄What the words mean用語メモ
此刻now現在
—
- 今天的位置Today今日の位置
- 橘色刻度＝現在的節氣，白色刻度＝下一個Orange tick = current term, white tick = next橙の目盛り＝いまの節気、白の目盛り＝次の節気
- 側看時你站的地方Where the side view looks from横から見るときの視点
- 近日點Perihelion近日点
- 遠日點Aphelion遠日点
從北方往下看地球公轉，地軸永遠指向同一個方向。拖著地球繞太陽一圈，就是快轉一整年；每個刻度是一個節氣。 Earth’s orbit seen from above the north. The axis always points the same way. Drag the Earth once around the Sun to run through a whole year; each tick is one solar term. 北から見下ろした地球の公転。地軸はいつも同じ向きです。地球を太陽のまわりに一周動かすと一年が進みます。目盛りひとつが節気ひとつ。
- 白天長度Daylight昼の長さ
- —
- 日出Sunrise日の出
- —
- 日落Sunset日の入り
- —
- 正午太陽高度Noon Sun height南中高度
- —
- 此刻太陽直射Sun overhead nowいま太陽の真下
- —
一整年的白天長度 — daylight through the yearの一年の昼の長さ
這些數字怎麼算的How the numbers are computed計算のしかた
節氣用「定氣法」：太陽視黃經每跨過 15° 的那一刻就是一個節氣，春分 0°、夏至 90°、秋分 180°、冬至 270°。太陽位置用 VSOP87 行星理論（Meeus《天文演算法》第 25 章的高精度算法，含 FK5 修正、章動與光行差）在你的瀏覽器裡算，再用 ΔT 從力學時換成世界時。和國立天文台公布的 2020、2025–2027 年共 96 個節氣時刻逐一比對，誤差都在 1 分鐘內；官方本身只公布到分鐘。 A solar term is the instant the Sun’s apparent ecliptic longitude crosses a multiple of 15°: the March equinox at 0°, the June solstice at 90°, the September equinox at 180°, the December solstice at 270°. The Sun’s position is computed in your browser from the VSOP87 planetary theory (the high-accuracy method in Meeus, Astronomical Algorithms, ch. 25, with the FK5 correction, nutation and aberration), then converted from Dynamical Time to Universal Time with ΔT. Checked against all 96 term instants the National Astronomical Observatory of Japan published for 2020 and 2025–2027, every one agrees within a minute — the published times are themselves rounded to the minute. 二十四節気は定気法で、太陽の視黄経が 15° の倍数を通過する瞬間です（春分 0°、夏至 90°、秋分 180°、冬至 270°）。太陽の位置は VSOP87 惑星理論（Meeus『Astronomical Algorithms』第25章の高精度法、FK5補正・章動・光行差を含む）でブラウザ内で計算し、ΔT で力学時から世界時に換算しています。国立天文台が公表した2020年と2025〜2027年の節気96件と照合し、すべて1分以内で一致しました（公表値自体が分単位です）。
節氣是一個瞬間，不是一整天，所以日期看你用哪個時區：中文頁用台灣時間（UTC+8，和中央氣象署相同），日文頁用日本時間（UTC+9，和国立天文台相同），英文頁用你裝置的時區。日出日落取太陽中心在地平線下 0.833°（大氣折射加太陽半徑），和氣象單位的慣例一樣，時間用該地點自己的時區；緯度夠高時會直接顯示永晝或永夜。你自己輸入或點選的地點，若在預設城市 100 公里內就用那座城市的時區；否則以經度每 15° 一小時估算，並會標明「依經度估計」。 A term is an instant, not a day, so its date depends on the clock you read it by: the Chinese page uses Taiwan time (UTC+8, as Taiwan’s Central Weather Administration does), the Japanese page Japan time (UTC+9, as NAOJ does), and this English page your device’s time zone. Sunrise and sunset use the standard convention of the Sun’s centre 0.833° below the horizon (refraction plus the solar radius), shown in the place’s own time zone; far enough north or south the tool says midnight sun or polar night instead. A place you type in or tap uses the time zone of a preset city within 100 km; anywhere else the zone is estimated from longitude, one hour per 15°, and labelled as estimated. 節気は一日ではなく一瞬なので、日付はどの時刻で読むかで変わります。中国語ページは台湾時間（UTC+8、台湾の中央気象署と同じ）、日本語ページは日本時間（UTC+9、国立天文台と同じ）、英語ページは端末のタイムゾーンを使います。日の出・日の入りは太陽の中心が地平線下0.833°（大気差と太陽の視半径）になる時刻で、その場所の現地時刻で表示します。高緯度では白夜・極夜と表示します。入力やタップで選んだ場所は、100km以内に用意した都市があればその都市のタイムゾーンを使い、それ以外は経度15°ごとに1時間として推定し、推定であることを表示します。
地球影像來自 NASA Earth Observatory：白天是 Blue Marble Next Generation（Reto Stöckli，2004 年每月合成，所以十二月的畫面有西伯利亞和青藏高原的雪），夜晚是 Earth at Night 2012（NASA／NOAA）。使用 NASA 影像不代表 NASA 背書。這個工具只做太陽與地球的幾何；七十二候、農曆月份與閏月（請見月相工具）、天氣，以及任何養生、宜忌內容都不在範圍內。 Earth imagery is from NASA Earth Observatory: the day side is Blue Marble Next Generation (Reto Stöckli, one composite per month of 2004 — which is why December shows snow across Siberia and the Tibetan Plateau), the night side is Earth at Night 2012 (NASA/NOAA). Use of NASA imagery does not imply NASA’s endorsement. The tool covers the geometry of the Sun and the Earth only; the 72 pentads, lunar months and leap months (see the moon phase tool), weather, and any health or almanac advice are out of scope. 地球の画像は NASA Earth Observatory のものです。昼側は Blue Marble Next Generation（Reto Stöckli、2004年の月ごとの合成。12月の画像でシベリアやチベット高原に雪があるのはそのため）、夜側は Earth at Night 2012（NASA／NOAA）。NASA 画像の使用は NASA による推奨を意味しません。このツールは太陽と地球の幾何だけを扱い、七十二候、旧暦の月や閏月（月齢ツールを参照）、天気、健康や暦注の内容は扱いません。
Quick guide
Use cases, answers, and nearby tools
Compact below-tool notes that help first-run users and repeated visitors move faster without changing the main interface.
Chinese search: 今天是什麼節氣、下一個節氣 日期、為什麼會有四季、冬至 為什麼最冷、節氣 為什麼每年不一樣
Japanese search: 二十四節気 今日、次の節気 いつ、季節 なぜ 起きる、冬至 夏至 いつ、地軸 傾き 季節
How to use
Run a clean first pass
- It opens on the present moment: the real Earth lit by the Sun, the current solar term, when it began, and the date and countdown to the next one.
- Drag the Earth around its orbit or press “Next term”: in the side view the axis leans toward the Sun at the June solstice and away in December, and the Arctic follows into midnight sun and polar night.
- Pick a place, or tap anywhere on the globe, to read its sunrise, sunset and noon Sun height, and a curve of its daylight across the whole year.
Examples
Real jobs this page helps with
- Which solar term is it todayNothing to set up: the current term, how many days this stretch lasts, and a countdown to the next term are on screen as soon as it opens.
- Midnight sun in the north, long summer days in the southJump to the December solstice with Melbourne or Sydney: the yellow part of your latitude line is the long southern summer day, while the whole Arctic Circle sits in night. Switch to Tromsø and daylight reads “Polar night”.
- One instant, two calendar datesIn 2026 two terms fall between midnight in Taiwan and midnight in Japan, so the two countries print different dates — the card under the tool lists them.
FAQ
What people usually want to know
How are the solar terms defined, and why do their dates shift by a day or two each year?
The 24 solar terms use the "fixed qi" method (dìngqì): each term is the exact instant the Sun's apparent ecliptic longitude crosses a multiple of 15°. Because a tropical year is not a whole number of days (~365.2422 d), the instants drift about 6 hours later each year and jump back a day in a leap year, so the same term falls on a window of 1–2 calendar dates. The tool computes each year's actual instants from the astronomical series rather than looking them up in a fixed table.
Why can the same term fall on different dates in Taiwan and Japan?
A solar term is an instant, not a day. Taiwan dates terms in UTC+8 (the Central Weather Administration’s convention) and Japan in UTC+9 (NAOJ’s), so an instant close to midnight lands on different calendar days. The 2026 Yǔshuǐ (Rain Water) term is 00:52 on 19 February in Japan but 23:52 on 18 February in Taiwan. The tool lists every such split for the year on screen.
Earth is closest to the Sun in early January — so why is it winter in the north and summer in the south?
Seasons come from the tilt of Earth's axis, not its distance from the Sun. Earth passes perihelion between 2 and 5 January, only about 3% closer than at aphelion (roughly 7% more sunlight). At that moment the northern half leans away from the Sun and has winter, while the southern half leans toward it and has summer — the same closest approach gives opposite seasons, which is why distance can't be the cause. The orbit diagram marks perihelion right beside the December solstice.
How accurate are the times?
The Sun’s position comes from the VSOP87 planetary theory (the high-accuracy method of Meeus, Astronomical Algorithms, ch. 25, with the FK5 correction, nutation and aberration), and each term is solved for exactly, then corrected for ΔT. Against all 96 term instants published by the National Astronomical Observatory of Japan for 2020 and 2025–2027, every one agrees within a minute — and the published times are themselves rounded to the minute.
What is left out of scope?
The 72 pentads (short five-day seasons), lunar month numbering and intercalary months (those belong to the moon-phase tool), weather or temperature data, and any health, dietary, fortune, or astrological content. The tool answers one pair of questions: which solar term it is and why the seasons turn on those days.