Japan's Real Seasonal Calendar: 24 Sekki + 72 Microseasons, Mapped to Your Trip Dates

Japan doesn’t have four seasons. Officially, it has 24. And if you’re really paying attention — the way an Edo-period court astronomer was paying attention in 1685 — it has 72.

That isn’t a poetic flourish. It’s a working calendar that every wagashi shop, kaiseki kitchen, kimono designer, shrine office, and tea school in the country still uses to pick what to serve, weave, and burn incense for this week. Right now, while you’re reading this, Japan is in the microseason called Botan hana saku — “peonies blossom” — which runs April 30 to May 4. That’ll get replaced on May 5 by Kawazu hajimete naku — “frogs are croaking again.” And that’s the thing about this calendar: it isn’t seasons in the abstract. It’s an instruction for what to look at this week and not next week.

Western travel writing about Japan tends to collapse all of this into “spring,” “rainy season,” “summer,” and the famously photogenic “autumn leaves.” That’s not wrong — it’s the resolution at which you’d describe a Mark Rothko painting as “red and orange.” The 72 microseasons are how Japan describes the same painting at the brushstroke level.

This is the version of that calendar I wish someone had handed me on my second trip. The system itself, the full table of 24 sekki, a mapped sample of the 72 kō (microseasons), the most surreal ones, and — most importantly — how to figure out which microseason your trip lands in and what’s eaten, blooming, or making noise during it.

Why this matters for your trip

Japan’s “limited” culture is the deepest layer of its travel value. A single sweet shop in Kyoto might rotate twelve different namagashi (fresh wagashi) over a month — not by vibe, but specifically because Botan hana saku is happening. Sushi counters change neta the week mackerel switches from spring-fat to summer-lean. McDonald’s Japan releases a sakura McShake during exactly two of the 72 microseasons and never otherwise. A kaiseki dinner in May won’t repeat anywhere else in the calendar — not the dishes, not the dishware, not the ikebana on the table.

If you arrive thinking “spring,” you’ll see cherry blossoms and wagashi shaped like cherry blossoms, and you’ll like it. If you arrive thinking “the third microseason of Shunbun, Sakura hajimete saku,” you’ll notice that the wagashi is shaped specifically to evoke the moment a cherry tree first opens — and that this exact sweet won’t be on the shelf next week. The microseasons aren’t more accurate; they’re better instructions for what to look for.

Most “When to visit Japan” articles are written for the median traveler trying to dodge tsuyu. Once you’ve been twice, you start optimizing differently — for Kusaretaru kusa hotaru to naru (mid-June fireflies) instead of avoiding rain, for Momiji tsuta kibamu (early November maple turn) instead of “autumn.” This calendar is the tool for that.

The system, briefly

The 24 sekki are solar terms: 24 equal divisions of the solar year, each about 15 days long, marking astronomical points in Earth’s orbit. They came from ancient China and are recalculated annually by the National Astronomical Observatory of Japan. Risshun (the start of the calendar) was February 4 in 2026. Each sekki has a descriptive name — Keichitsu (awakening of insects), Geshi (summer solstice), Hakuro (white dew).

The 72 kō are a finer subdivision: each sekki splits into three roughly five-day microseasons. The Chinese originals referenced Yellow River weather, not Honshu weather, so in 1685 a court astronomer named Shibukawa Shunkai rewrote the whole list to match what was happening outside his window in Kyoto. That rewritten version is still in use. The names are short observations: Tsubame kitaru (swallows return), Niji hajimete arawaru (first rainbows appear), Kuma ana ni komoru (bears hide in dens).

The 24 sekki at a glance (with 2026 dates)

The full table. All dates calculated for 2026. Use this as the spine for the rest of the article.

#	Sekki	Meaning	2026 dates	What’s actually happening
1	Risshun 立春	Beginning of spring	Feb 4 – Feb 18	Plum blossoms; setsubun bean-throwing the day before
2	Usui 雨水	Rainwater	Feb 19 – Mar 4	Snow turns to rain; first hina-matsuri prep
3	Keichitsu 啓蟄	Awakening of insects	Mar 5 – Mar 19	Hibernating bugs come out; first peach blossoms
4	Shunbun 春分	Spring equinox	Mar 20 – Apr 4	National holiday; sakura opens (Tokyo bloom Mar 19, peak Mar 27)
5	Seimei 清明	Clear and bright	Apr 5 – Apr 19	Sakura peak in central Japan (Kyoto peak Apr 1); first rainbows
6	Kokuu 穀雨	Rain for harvests	Apr 20 – May 4	Rice seedlings sprout; peonies open; you are reading this in Kokuu
7	Rikka 立夏	Beginning of summer	May 5 – May 20	Frogs croak; bamboo shoots; Children’s Day
8	Shōman 小満	Small wealth	May 21 – Jun 5	Wheat ripens; safflowers; silkworms feeding
9	Bōshu 芒種	Ears full of seeds	Jun 6 – Jun 20	Rice-planting season; fireflies; tsuyu begins (Tokyo around Jun 7)
10	Geshi 夏至	Summer solstice	Jun 21 – Jul 6	Longest day; iris blooms; deepest tsuyu
11	Shōsho 小暑	Lighter heat	Jul 7 – Jul 22	Tanabata; lotus blooms; tsuyu ends (around Jul 19 in Kanto)
12	Taisho 大暑	Greater heat	Jul 23 – Aug 6	Peak summer; cicadas; natsumatsuri season
13	Risshū 立秋	Beginning of autumn	Aug 7 – Aug 22	Calendar autumn (it’s still 35°C); cool wind at night
14	Shosho 処暑	Decreasing heat	Aug 23 – Sep 6	Heat finally recedes; rice harvest begins
15	Hakuro 白露	White dew	Sep 7 – Sep 22	Mornings cool; otsukimi moon-viewing prep
16	Shūbun 秋分	Autumn equinox	Sep 23 – Oct 7	National holiday; insects burrow for winter
17	Kanro 寒露	Cold dew	Oct 8 – Oct 22	Wild geese return; chrysanthemums; crickets at the door
18	Sōkō 霜降	Frost descends	Oct 23 – Nov 6	First frosts up north; maple leaves turn
19	Rittō 立冬	Beginning of winter	Nov 7 – Nov 21	Camellias open; Tokyo koyō peak around Nov 20
20	Shōsetsu 小雪	Light snow	Nov 22 – Dec 6	Rainbows disappear; Kyoto koyō peak around Dec 5
21	Taisetsu 大雪	Heavy snow	Dec 7 – Dec 21	Salmon swim upriver; bears hibernate; ski season starts
22	Tōji 冬至	Winter solstice	Dec 22 – Jan 4	Shortest day; yuzu-yu bath tradition; New Year
23	Shōkan 小寒	Lighter cold	Jan 5 – Jan 19	Pheasants call; Japanese parsley grows; New Year cleanup
24	Daikan 大寒	Greater cold	Jan 20 – Feb 3	Coldest stretch of the year; setsubun closes the cycle

A note on the dates: Risshu and Risshun shift by a day in some years. The 2026 column above uses the NAOJ-calculated dates for this year specifically. If you’re reading this in 2027, Risshun will be either Feb 3 or Feb 4 again — but the structure is identical.

How the 72 microseasons actually work (with 10 examples)

Each sekki contains three kō. The naming convention is short, declarative, observational — somebody in 17th-century Kyoto wrote down what was happening outside and put it in a calendar.

A small selection, picked to show the range:

1. Harukaze kōri o toku (春風氷を解く) — “East wind melts the ice” | Feb 4–8 | The first kō of the year.
2. Uguisu naku (黄鶯睍睆) — “Bush warblers start singing” | Feb 9–13 | If you’re hiking and hear ho-hokekyo, this is it.
3. Kasumi hajimete tanabiku (霞始靆) — “Spring mist lingers” | Feb 24–28 | The whole calendar doing its job.
4. Namushi chō to naru (菜虫化蝶) — “Caterpillars become butterflies” | Mar 15–19 | Famous and exact.
5. Sakura hajimete saku (桜始開) — “Cherry blossoms first open” 🌸 | Mar 25–29 | The microseason every traveler is unknowingly trying to optimize for.
6. Kaminari sunawachi koe o hassu (雷乃発声) — “Distant thunder rumbles” | Mar 30–Apr 4 | Spring storms.
7. Kusaretaru kusa hotaru to naru (腐草為螢) — “Rotten grass becomes fireflies” | Jun 12–15 | The most surreal name in the calendar.
8. Taka sunawachi waza o narau (鷹乃学習) — “Young hawks learn to fly” | Jul 17–22 | Mid-summer. Hawks practicing.
9. Tsubame saru (玄鳥去) — “Swallows fly south” | Sep 17–22 | The April swallows leave now.
10. Sake no uo muragaru (鮭魚群) — “Schools of salmon swim upriver” | Dec 17–21 | In Hokkaido or Tohoku, you can literally watch this.

The whole 72 follow this rhythm. Three observations per sekki, each specific enough to only refer to a single five-day window. I keep a few on a sticky note next to my monitor and check them off as they tick over.

The 7 most surreal microseason names

Some of these names sound less like a calendar and more like a fortune cookie left in a humidor for 350 years. The strangeness is itself a piece of cultural information.

1. Kusaretaru kusa hotaru to naru — “Rotten grass becomes fireflies” (Jun 12–15). The most famous one. Pre-modern observers noticed fireflies emerging from damp decaying grass and concluded — not unreasonably — that the grass was becoming the fireflies. The phrase survived as a proverb for “the impossible happens.”

2. Suzume hajimete suku — “Sparrows start building nests” (Mar 20–24). Reasonable on its face, except elsewhere in East Asian seasonal tradition the autumn counterpart is “sparrows enter the sea and become clams.” Japan’s 1685 rewrite cleaned that up, but the underlying medieval idea was that small birds transformed into shellfish in winter.

3. Hange shōzu — “Crow-dippers are sprouting” (Jul 2–6). Pinellia ternata, a small medicinal herb used in kampo. An entire microseason named after one obscure plant tells you how seriously this calendar was taken by 17th-century herbalists.

4. Tsuchi uruote mushi atsushi — “Ground and atmosphere dampen” (Jul 28–Aug 1). The peak of Japanese summer humidity, given a name. Anyone who’s been in Tokyo in late July knows exactly what microseason this is — and there’s real comfort in knowing the calendar acknowledges your suffering.

5. Niji kakurete miezu — “Rainbows hide and cannot be seen” (Nov 22–26). The mirror of Niji hajimete arawaru in April. Nothing actually happens here — the microseason is the absence of something. A pretty advanced move for a 1685 calendar.

6. Sawashika no tsuno otsuru — “Deer shed their antlers” (Dec 27–31). If you’re in Nara during the last week of December, this is literally happening. Nara Park’s deer shed once a year and the antlers are ceremonially collected at Kasuga Taisha.

7. Niwatori hajimete toya ni tsuku — “Hens start brooding” (Jan 30–Feb 3). The last microseason of the year. The calendar ends — right before Risshun loops it back to spring — with chickens settling onto eggs. The Japanese seasonal calendar doesn’t end with a big symbolic finale; it ends with hens going to bed.

”If you visit in [month]” — the practical month-by-month map

This is the section you’ll come back to. For each month I’ve picked the headline microseason, the food/object/event that’s actually limited-edition during it, and one travel hack.

January — Daikan Microseason of note: Sawamizu kōri tsumeru (Jan 25–29) — “Mountain rivers freeze solid.” Limited: Hot kasujiru (sake-lees soup) at almost every soba shop. Hack: The two coldest weeks of the year are also when Tokyo is at its emptiest of tourists. Hit Sensō-ji at 7am.

February — Risshun Microseason of note: Uo kōri o izuru (Feb 14–18) — “Fish are freed from the ice.” Limited: Sakura-mochi at every wagashi shop the day Risshun begins, even though sakura won’t bloom for six weeks. The shape is the anticipation. Hack: Setsubun (Feb 3) at any major shrine for free roasted soybeans and ritual demon-yelling.

March — Keichitsu / Shunbun Microseason of note: Sakura hajimete saku (Mar 25–29) — “Cherry blossoms first open.” Limited: Sakura everything. Starbucks Japan releases its sakura latte in early March. McDonald’s releases a sakura McShake in late March. Wagashi shops have sakuramochi, hanamizake, sakurayu. Hack: Tokyo’s 2026 sakura forecast was bloom Mar 19, peak Mar 27. Kyoto bloom Mar 23, peak Apr 1. The eight-day gap is your travel window.

April — Seimei / Kokuu Microseason of note: Tsubame kitaru (Apr 5–9) — “Swallows return.” Limited: Hatsu-gatsuo (first bonito of the year) on sushi counters. Hack: Late April after Golden Week prep but before crowds is the underrated sweet spot. Botan hana saku (peony season, Apr 30) at Tsurugaoka Hachimangū.

May — Rikka / Shōman Microseason of note: Kawazu hajimete naku (May 5–9) — “Frogs are croaking again.” Limited: Kashiwa-mochi for Children’s Day (May 5) — only sold this week. Chimaki in Kyoto. Hack: Late May (Benibana sakau) is one of the most underrated travel windows in Japan. Weather is perfect, rates are low, fireflies are starting to glow.

June — Bōshu / Geshi Microseason of note: Kusaretaru kusa hotaru to naru (Jun 12–15) — “Rotten grass becomes fireflies.” Limited: Minazuki (a triangular wagashi eaten only on June 30 — Kyoto tradition for purifying the half-year). Plum-related everything during Ume no mi kibamu (Jun 16–20). Hack: Tsuyu officially starts around Jun 7 in Kanto and ends around Jul 19. The rain isn’t the disaster Western blogs make it out to be — hydrangea (ajisai) season is wet because that’s how it works.

July — Shōsho / Taisho Microseason of note: Taka sunawachi waza o narau (Jul 17–22) — “Young hawks learn to fly.” Limited: Doyō no ushi no hi (mid-July) — the day every restaurant in Japan serves grilled eel. Hack: Tanabata (Jul 7) is the start of Shōsho. Hang a wish on a bamboo branch at any major shrine.

August — Taisho / Risshū Microseason of note: Higurashi naku (Aug 12–16) — “Evening cicadas start singing.” Limited: Obon fireworks across the country. Cold somen noodles served on bamboo flumes (nagashi-somen). Hack: The first week of Risshū (Aug 7) is “calendar autumn.” It’s still 35°C, but izakaya menus officially flip to autumn ingredients overnight. Slightly absurd, totally charming.

September — Hakuro / Shūbun Microseason of note: Tsubame saru (Sep 17–22) — “Swallows fly south.” Limited: Tsukimi dango for moon-viewing — sold for exactly one week around mid-autumn full moon. McDonald’s tsukimi burger (yes, it counts). Hack: September is the secret tsuyu — typhoon season, but also the cheapest accommodation rates of the year.

October — Kanro / Sōkō Microseason of note: Kiku no hana hiraku (Oct 13–17) — “Chrysanthemums blossom.” Limited: Kuri (chestnut) in every form. Matsutake mushroom dishes. Shinmai (new rice) appears on signage. Hack: Imperial chrysanthemum exhibitions at Shinjuku Gyoen are free during Kanro — most travelers walk past.

November — Sōkō / Rittō Microseason of note: Momiji tsuta kibamu (Nov 2–6) — “Maple and ivy turn yellow.” Limited: The full koyō economy kicks in. Tokyo’s 2026 peak around Nov 20 (Mt. Takao Nov 18). Kyoto’s around Dec 5. Hack: The week between Tokyo peak and Kyoto peak (Nov 22–28, Shōsetsu opens) is the optimal Tokyo→Kyoto travel sequence. Catch Tokyo at peak, Shinkansen down, catch Kyoto a week later.

December — Taisetsu / Tōji Microseason of note: Sake no uo muragaru (Dec 17–21) — “Salmon swim upriver.” Limited: Yuzu-yu baths on the winter solstice (Tōji, Dec 22) — every onsen and sentō floats yuzu fruits in the water. Toshikoshi soba on Dec 31. Hack: Tōji is mathematically the best onsen day of the year. Book a yuzu bath at any sentō for the full effect — the onsen etiquette guide covers the rules, the Tokyo Sento Bible lists 63 foreigner-friendly options.

How locals actually use the calendar

The 72 microseasons aren’t a museum object. They’re embedded in working culture.

Wagashi shops design new sweets for each microseason — about 36 a year, doubled for paired versions. Toraya, Tsuruya Yoshinobu, and Suetomi all publish seasonal calendars. Walk in and ask “what’s the microseason sweet right now?” and the staff will know exactly what you mean.

Kaiseki kitchens are structurally a microseason performance. The hassun course (seasonal centerpiece) changes every two weeks. Tea ceremony tracks even more strictly — bowl, scroll, kettle, and incense all rotate.

Kimono patterns are picked by microseason. Wearing a chrysanthemum motif in April is technically a faux pas. Most tourists won’t notice; every Japanese person at the tea ceremony will.

Shrine calendars (nenchūgyōji) are published annually by every major shrine — Kasuga Taisha, Yasaka, Meiji Jingū. The Japan Meteorological Agency publishes microseason notes alongside its forecasts on the koyomi page; it’s Japanese-only but Google Translate works fine.

Practical travel use: Open a Japanese seasonal calendar app the day you arrive. Note the current microseason. Walk into one wagashi shop and ask for the sweet of the moment. That gives you a tasting baseline — every other meal, snack, and shop window starts making sense as variations on the same theme.

You’ll need a working data connection for this — most seasonal calendars and shrine pages are Japanese-only and benefit from real-time translation. I keep a Klook eSIM running on my second SIM slot whenever I’m doing seasonal-photo trips; it activates in five minutes and costs less than one train fare per day.

The traveler’s hack: chasing 3 sekki on one trip

Pick a route that crosses three sekki in two weeks.

A 14-day trip in late March 2026 lands you in Shunbun (cherry start, Tokyo) → Seimei (rainbow season, Kyoto) → maybe Kokuu (peony, if you stretch into early May). The calendar ticks over twice while you’re on the road. The food rotates with you. The shop windows rotate with you.

Same gambit in autumn: Kanro (early October, Tokyo, chrysanthemums) → Sōkō (late October, Kyoto, first frost) → Rittō (early November, Hokkaido or Nikko for early koyō). Three weather worlds, three menu worlds, three flower worlds.

This is one of the rare 2026 cases where the JR Pass math clearly pencils. The 7-day Pass covers Tokyo–Kyoto–Hokkaido or Tokyo–Kyoto–Nikko cleanly; the 14-day version covers a two-sekki crossing with room. The JR Pass option I’d buy is the regional or nationwide pass, depending on whether your chase stays in Honshu or jumps north — Hokkaido’s microseasons run about two weeks behind Tokyo’s, so a Hokkaido leg buys you back a microseason if you mistime the rest.

If you’re already turning the JR Pass into a tasting route, the 47-prefecture Ekiben Atlas maps every region’s signature train bento — the menu rotates with the microseason as much as the wagashi shops do.

What this calendar doesn’t do

Honest disclosures, because the 72 microseasons aren’t a perfect mystical system:

• Calibrated to 17th-century Kyoto. Frogs croak (May 5) is a week early in Hokkaido, a week late in Okinawa. Honshu midpoint.
• Climate change has shifted things. Sakura hajimete saku used to be Apr 5; it’s now meaningfully ahead. The calendar hasn’t been updated since 1685 and probably won’t be.
• Most Japanese people don’t memorize all 72. They use the 24 sekki actively (every weather forecast says them) and the 72 kō culturally (every wagashi shop, every kaiseki kitchen). Ask someone on the street and they probably don’t know either. Fine.

What to look for the day you land

If you’re arriving in Japan in the next month or two:

1. Check the date against the table above. Identify your sekki.
2. Identify your current microseason from the list.
3. Walk into a depachika (department store food basement). Find the wagashi counter. Ask what’s seasonal this week. Buy whichever sweet looks most specific to right now.
4. Eat it sitting down somewhere. Notice that the shape, color, and name reference exactly what’s outside.

That’s the whole technique. The calendar is the tool that makes the question “what’s specific to right now?” askable.

The best version I’ve done was a single small sweet in late February in Kanazawa, shaped like a translucent piece of half-melted ice with a flake of gold leaf in the middle. It was called Uo kori o izuru — “fish are freed from the ice” — and I was eating it during exactly that microseason, on a bench outside a confectionery shop, watching steam come off a canal. Three bites. ¥450. It’ll be the one thing I remember from that trip in twenty years.

If you came to Japan to chase four seasons, you’ll see them. If you came for 24, you’ll see more. If you came for the 72, you’ll see what 17th-century Kyoto saw — which is, I think, what people actually mean when they say Japan is a country built around noticing.

Further reading

• Flagship: Onsen Etiquette: The Unwritten Rules — for booking your yuzu-yu bath on Tōji (Dec 22), the calendrical best onsen day of the year.
• Flagship: Ekiben Atlas: 47 Prefectures — train bento that rotates with the microseason as much as wagashi does.
• TIL: KFC for Christmas — a 1974-invented seasonal ritual now wedged into the Tōji microseason.
• TIL: Hadaka Matsuri (the naked festival) — third Saturday of February, in Risshun.
• TIL: The 100-km Obon traffic jam — what mid-August looks like in Risshū.