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Mean temperature across the twenty-four solar terms — the climate this calendar was written for

Climate reading

Chicago and the Chinese solar calendar

In Chicago, the first freeze typically comes October 19, 4 days before the calendar's Frost's Descent begins on October 23. The last freeze is typically over by April 22, and Chicago gets 177 days a year without one. Where the calendar and your weather disagree, go by your weather.

The weather station behind this page

Weather stationO'Hare, IL
Station IDUSW00094846
Days without a freeze, per year177
Typical first freezeOctober 19
Typical last freezeApril 22
Rain and heatr = -0.18 (no clear pattern)
Years averaged1991–2020

Official NOAA averages for 1991–2020 at this station: a typical year, not a forecast.

Right now

Rain and heat across the whole year

Here rainy days are spread through the year instead of bunching up in the hot months as they do where the calendar comes from, so the calendar's muggy season has no clear match in Chicago. On a scale from −1 (opposite) to 1 (perfectly together), Chicago scores -0.18 and the calendar's home region 0.88.

Where the calendar is most wrong about Chicago

These four two-week stretches are where the calendar's names or advice sit furthest from Chicago's thirty-year record.

Major Cold 大寒from 2026-01-20

The old calendar's three signs for these weeks, one per five days: 鸡乳 · 征鸟厉疾 · 水泽腹坚

The Su Wen, part of the Yellow Emperor's Inner Classic, calls winter the season of closing and storing (閉藏). Go to bed early and get up late, once the sun is up; stay warm without sweating. That keeps you in step with winter. Go against it, the text warns, and the kidneys suffer, showing up in spring as weakness and collapse (痿厥).

Average, low, high24.8°F / 18.2°F / 31.5°F
Days with measurable rain33.8%
Days at or below freezing13.4
Daylight9h 34m (+20 min from two weeks ago)
  • Where the calendar comes from, these weeks average about 34.0°F. At O'Hare, IL: 24.8°F, 9.2°F cooler.
  • 'Major Cold' names what people in the Yellow River valley saw in nature, not a temperature. At O'Hare, IL, the last freeze of spring typically doesn't clear until April 22, still 92 days away; these weeks usually bring about 13.4 freezing days.

Yang deficiency (running low on the body's warmth) traditionally finds winter hard. Here the average low this stretch is 18.2°F.

Minor Cold 小寒from 2026-01-05

The old calendar's three signs for these weeks, one per five days: 雁北乡 · 鹊始巢 · 雉雊

The winter advice above covers these weeks too.

Average, low, high25.3°F / 19.0°F / 31.6°F
Days with measurable rain35.3%
Days at or below freezing13.6
Daylight9h 14m (+7 min from two weeks ago)
  • Where the calendar comes from, these weeks average about 33.1°F. At O'Hare, IL: 25.3°F, 7.8°F cooler.
  • 'Minor Cold' names what people in the Yellow River valley saw in nature, not a temperature. At O'Hare, IL, the last freeze of spring typically doesn't clear until April 22, still 107 days away; these weeks usually bring about 13.6 freezing days.

Qi stagnation (energy that gets stuck, often felt as low spirits) traditionally finds gray, rainy stretches hard. Rain falls on 35.3% of days in this stretch, against 34.4% across Chicago's year.

Major Snow 大雪from 2026-12-07

The old calendar's three signs for these weeks, one per five days: 鹖鴠不鸣 · 虎始交 · 荔挺出

The winter advice above covers these weeks too.

Average, low, high30.8°F / 24.8°F / 36.9°F
Days with measurable rain34.2%
Days at or below freezing12.3
Daylight9h 13m (-19 min from two weeks ago)
  • Where the calendar comes from, these weeks average about 36.3°F. At O'Hare, IL: 30.8°F, 5.5°F cooler.
  • 'Major Snow' names what people in the Yellow River valley saw in nature, not a temperature. At O'Hare, IL, half of all years have had their first freeze by October 19, 49 days before these weeks begin; they usually bring about 12.3 freezing days.

Blood stasis (blood that doesn't move freely) traditionally finds cold hard. Here the average low this stretch is 24.8°F.

Minor Snow 小雪from 2026-11-22

The old calendar's three signs for these weeks, one per five days: 虹藏不见 · 天气上升地气下降 · 闭塞而成冬

The winter advice above covers these weeks too.

Average, low, high35.6°F / 29.1°F / 42.2°F
Days with measurable rain33.4%
Days at or below freezing9.3
Daylight9h 32m (-30 min from two weeks ago)
  • Where the calendar comes from, these weeks average about 40.6°F. At O'Hare, IL: 35.6°F, 5.0°F cooler.
  • 'Minor Snow' names what people in the Yellow River valley saw in nature, not a temperature. At O'Hare, IL, half of all years have had their first freeze by October 19, 34 days before these weeks begin; they usually bring about 9.3 freezing days.

All twenty-four two-week stretches in Chicago

Two weeks BeginsAvg °FRainy days %Freezing daysvs. calendar °F
Minor Cold小寒2026-01-0525.335.313.6-7.8
Major Cold大寒2026-01-2024.833.813.4-9.2
Start of Spring立春2026-02-0427.332.811.8-11.0
Rain Water雨水2026-02-1832.333.712.7-10.5
Awakening of Insects惊蛰2026-03-0537.734.79.6-10.3
Spring Equinox春分2026-03-2042.936.58.5-10.9
Pure Brightness清明2026-04-0548.339.83.0-10.5
Grain Rain谷雨2026-04-2053.941.72.2-10.7
Start of Summer立夏2026-05-0559.441.20.1-8.2
Grain Buds小满2026-05-2164.639.70.1-7.7
Grain in Ear芒种2026-06-0569.837.00.0-6.7
Summer Solstice夏至2026-06-2174.033.20.0-5.0
Minor Heat小暑2026-07-0775.631.90.0-4.5
Major Heat大暑2026-07-2375.331.80.0-6.0
Start of Autumn立秋2026-08-0774.130.40.0-4.2
End of Heat处暑2026-08-2371.728.80.0-3.1
White Dew白露2026-09-0766.829.10.1-1.7
Autumn Equinox秋分2026-09-2360.631.10.6-3.3
Cold Dew寒露2026-10-0854.433.01.3-4.6
Frost's Descent霜降2026-10-2348.433.83.7-5.0
Start of Winter立冬2026-11-0741.933.47.2-4.7
Minor Snow小雪2026-11-2235.633.49.3-5.0
Major Snow大雪2026-12-0730.834.212.3-5.5
Winter Solstice冬至2026-12-2227.535.111.8-6.3

‘vs. calendar’ is how much warmer (+) or cooler (−) each stretch runs here than where the calendar comes from. Rain figures count rainy days, not inches.

The body-type notes follow traditional Chinese medicine as set out in a national standard in China. Tying them to this city's weather is a traditional association, not a finding from modern research. Which type goes with which stretch is our own arrangement: each is matched to the time of year the standard says it finds hard, or, for rain, to the rainiest of the four when it's wetter than Chicago's year as a whole. Weather doesn't decide anyone's body type. To find yours, take the assessment.

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How Chicago compares with the other thirteen

Chicago has 177 frost-free days a year, more than 2 of the other cities here. That's 26 more than Denver, which has the fewest. It's 188 fewer than San Francisco, which has the most.

Rain falls on 34.4% of days here over a year. Phoenix is the driest of the fourteen at 9.2% and Seattle the wettest at 43.1%, which puts Chicago at the wet end.

The hottest two weeks here are Minor Heat, with an average high of 84.7°F and rain on 31.9% of days: never especially hot. 8 of the fourteen get hotter at their peak, Phoenix among them.

The other thirteen cities

All fourteen cities side by side

Where this comes from

The thirty-year averages are NOAA's official 1991–2020 figures, one station per city, read straight from NOAA's records by our own program. Freezing days for each two-week stretch are estimated from NOAA's monthly counts. Figures for where the calendar comes from are based on weather-station measurements and reanalysis data from the Yellow River valley in northern China, where the calendar's names come from. The seasonal advice comes from the Su Wen, in our own translation.

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