Constitution MapNine patterns · 14 US cities

Climate reading

Seattle and the Chinese solar calendar

Seattle gets 259 freeze-free days a year, with a median first freeze on November 21. The calendar names a fortnight Frost’s Descent and opens it on 23 October. Rain and heat here move in opposite directions (r = -0.99), where the calendar’s home climate has them arriving together (r = 0.88). Advice built on hot-and-wet does not describe this place.

The station this page reads from

Weather stationSea-Tac, WA
Station IDUSW00024233
Freeze-free days / year259
Median first freezeNovember 21
Median last freezeMarch 8
Rain vs. heatr = -0.99 (inverted)
Normals period1991–2020

NOAA NCEI 1991–2020 U.S. Climate Normals. A normal is a thirty-year average, not a forecast and not any single year’s weather.

Right now

Rain and heat across the whole year

The classical calendar assumes rain and heat arrive together — across the 24 fortnights the prototype's rainy days and temperature run together (r = 0.88). Where you are they run opposite (r = -0.99): your rainiest fortnights are your coldest. Every piece of seasonal advice built on 'damp heat' lands differently here.

Where the calendar is most wrong about Seattle

Of the twenty-four fortnights, these four are the ones whose name or advice sits furthest from what Seattle’s weather station actually recorded over thirty years.

Cold Dew 寒露from 2026-10-08

Pentads: 鸿雁来宾 · 雀入大水为蛤 · 菊有黄华

containment and levelling (容平 róng píng). Go to bed early and rise early, up with the rooster.

This is the response to autumn qi — the way of nourishing the gathering-in (養收). Going against it is said to injure the lung, so that winter brings undigested diarrhoea and there is less to carry the storing.

Su Wen, 'Four Qi Regulate the Spirit' (素問·四氣調神大論); pentads from the Yue Ling Qi Shi Er Hou Ji Jie

Average / low / high53.9°F / 47.2°F / 60.7°F
Days with measurable rain45.1%
Days at or below freezing0.1
Daylight11h 10m (-52 min from two weeks ago)
  • This fortnight's advice was written for a place averaging 59.0°F at this point in the year. At Sea-Tac, WA the 1991–2020 average is 53.9°F — cooler by 5.1°F.
  • 'Cold Dew' is a phenological marker from the Yellow River valley — what observers saw, not a temperature threshold. The nearest thing your own record has to it: at Sea-Tac, WA the first freeze of autumn has arrived by November 21 in half of years — 44 days after this fortnight begins. This fortnight typically carries about 0.1 days at or below freezing.
  • This is the fastest-cooling fortnight of your year: 4.7°F below the one before it.

If Yin deficiency came out high for you. Traditional theory associates Yin deficiency with internal dryness and a sense of heat from within. That is a theoretical association drawn from the classical literature, not a research finding. Your average high this fortnight is 60.7°F, and 45.1% of days typically see measurable rain. Whether any of it matters for you is something to observe, not something this page can tell you.

Start of Summer 立夏from 2026-05-05

Pentads: 蝼蝈鸣 · 蚯蚓出 · 王瓜生

flourishing and blooming (蕃秀 fán xiù). Go to bed late and rise early; do not resent the long day.

This is the response to summer qi — the way of nourishing growth (養長). Going against it is said to injure the heart, so that autumn brings intermittent fevers and there is less to carry the gathering-in.

Su Wen, 'Four Qi Regulate the Spirit' (素問·四氣調神大論); pentads from the Yue Ling Qi Shi Er Hou Ji Jie

Average / low / high57.0°F / 48.1°F / 65.8°F
Days with measurable rain38.4%
Days at or below freezing0.0
Daylight14h 37m (+47 min from two weeks ago)
  • This fortnight's advice was written for a place averaging 67.6°F at this point in the year. At Sea-Tac, WA the 1991–2020 average is 57.0°F — cooler by 10.6°F.
  • This is the fastest-warming fortnight of your year: 3.5°F above the one before it.

If Damp-heat came out high for you. Traditional theory associates Damp-heat with damp and heat arriving together, rather than either one alone. That is a theoretical association drawn from the classical literature, not a research finding. This fortnight runs to an average high of 65.8°F with rain on about 38.4% of days. Whether any of it matters for you is something to observe, not something this page can tell you.

White Dew 白露from 2026-09-07

Pentads: 鸿雁来 · 元鸟归 · 群鸟养羞

Same seasonal passage as above — the classical text gives one instruction per season, not one per fortnight.

Average / low / high63.0°F / 53.9°F / 72.1°F
Days with measurable rain28.3%
Days at or below freezing0.0
Daylight12h 58m (-51 min from two weeks ago)
  • This fortnight's advice was written for a place averaging 68.5°F at this point in the year. At Sea-Tac, WA the 1991–2020 average is 63.0°F — cooler by 5.5°F.
  • 'White Dew' is a phenological marker from the Yellow River valley — what observers saw, not a temperature threshold. The nearest thing your own record has to it: at Sea-Tac, WA the first freeze of autumn has arrived by November 21 in half of years — 75 days after this fortnight begins. This fortnight typically carries about 0.0 days at or below freezing.

If Yang deficiency came out high for you. Traditional theory associates Yang deficiency with feeling the cold sooner than the people around you. That is a theoretical association drawn from the classical literature, not a research finding. Your average low this fortnight is 53.9°F, and about 0.0 days typically fall to freezing or below. Whether any of it matters for you is something to observe, not something this page can tell you.

Summer Solstice 夏至from 2026-06-21

Pentads: 鹿角解 · 蜩始鸣 · 半夏生

Same seasonal passage as above — the classical text gives one instruction per season, not one per fortnight.

Average / low / high64.2°F / 54.7°F / 73.8°F
Days with measurable rain23.8%
Days at or below freezing0.0
Daylight15h 58m (+11 min from two weeks ago)
  • This fortnight's advice was written for a place averaging 79.0°F at this point in the year. At Sea-Tac, WA the 1991–2020 average is 64.2°F — cooler by 14.8°F.

If Qi stagnation came out high for you. Traditional theory associates Qi stagnation with mood that moves with the season; the classical texts tie autumn's gathering-in to it in particular. That is a theoretical association drawn from the classical literature, not a research finding. Daylight at your latitude is 15h 58m, up 11 minutes from two weeks ago. Whether any of it matters for you is something to observe, not something this page can tell you.

All twenty-four fortnights at Seattle

Fortnight BeginsAvg °FRainy days %Freezing daysvs. calendar °F
Minor Cold小寒2026-01-0542.760.43.4+9.6
Major Cold大寒2026-01-2043.458.43.3+9.4
Start of Spring立春2026-02-0443.756.62.8+5.4
Rain Water雨水2026-02-1844.856.12.6+2.0
Awakening of Insects惊蛰2026-03-0546.655.30.9-1.4
Spring Equinox春分2026-03-2048.552.70.7-5.3
Pure Brightness清明2026-04-0550.650.00.1-8.2
Grain Rain谷雨2026-04-2053.544.80.0-11.1
Start of Summer立夏2026-05-0557.038.40.0-10.6
Grain Buds小满2026-05-2159.535.30.0-12.8
Grain in Ear芒种2026-06-0561.531.40.0-15.0
Summer Solstice夏至2026-06-2164.223.80.0-14.8
Minor Heat小暑2026-07-0767.116.80.0-13.0
Major Heat大暑2026-07-2368.313.80.0-13.0
Start of Autumn立秋2026-08-0767.615.30.0-10.7
End of Heat处暑2026-08-2365.921.00.0-8.9
White Dew白露2026-09-0763.028.30.0-5.5
Autumn Equinox秋分2026-09-2358.636.30.0-5.3
Cold Dew寒露2026-10-0853.945.10.1-5.1
Frost's Descent霜降2026-10-2350.053.70.7-3.4
Start of Winter立冬2026-11-0746.859.21.5+0.2
Minor Snow小雪2026-11-2243.960.22.3+3.3
Major Snow大雪2026-12-0741.960.43.5+5.6
Winter Solstice冬至2026-12-2241.861.13.2+8.0

‘vs. calendar’ is this fortnight’s local average minus the average where the calendar was written. Rain figures on this page count rainy days, not inches. The two can point opposite ways — summer storms drop more water on fewer days.

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