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Checking the NOAA OVATION feed

Chicago · April 2027

Northern lights in Chicago in April 2027

Answer

April gives Chicago 9.6 hours of civil night on the 15th, the 8th darkest of its 12 months, under 63% mean cloud. 1% of April days since 1996 reached Kp 8, enough for the oval edge to reach Chicago.
9.5 h
civil night, average night
SunCalc for 41.85, -87.65; NASA POWER; GFZ Kp

April against the rest of the year

April cloud at Chicago averages 63% in NASA POWER's 2001 to 2020 record, 3 points cloudier than its yearly mean. September is Chicago's clearest month at 46%. By civil night times clear sky, April scores 3.6 hours at Chicago, 10th of 12. Minneapolis, 571 km away, averages 61%, clearer by 2 points.

Civil night at Chicago starts April at 10 h 14 min and reaches 8 h 53 min by April 30, 1.4 hours shorter. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 7.2 hours on the 15th.

April night by night

April opens toward a new moon on Apr 6, with full moon on Apr 20, in America/Chicago dates. Chicago gets 150 hours of civil night with the moon below the horizon across the month. The best of them for moon-free darkness inside 10 PM to 2 AM: Apr 1 (4 h), Apr 2 (4 h), Apr 3 (4 h).

  1. 1

    22% lit

    8.8 h

  2. 2

    14% lit

    9.1 h

  3. 3

    8% lit

    9.4 h

  4. 4

    4% lit

    9.8 h

  5. 5

    1% lit

    10.1 h

  6. 6

    0% lit

    10.0 h

  7. 7

    2% lit

    9.3 h

  8. 8

    6% lit

    8.0 h

  9. 9

    12% lit

    6.8 h

  10. 10

    21% lit

    5.5 h

  11. 11

    31% lit

    4.5 h

  12. 12

    42% lit

    3.6 h

  13. 13

    53% lit

    2.9 h

  14. 14

    64% lit

    2.3 h

  15. 15

    75% lit

    1.8 h

  16. 16

    84% lit

    1.3 h

  17. 17

    91% lit

    0.9 h

  18. 18

    96% lit

    0.5 h

  19. 19

    99% lit

    0.1 h

  20. 20

    100% lit

    0.0 h

  21. 21

    98% lit

    0.9 h

  22. 22

    94% lit

    2.0 h

  23. 23

    89% lit

    3.0 h

  24. 24

    82% lit

    3.9 h

  25. 25

    74% lit

    4.7 h

  26. 26

    65% lit

    5.3 h

  27. 27

    56% lit

    5.8 h

  28. 28

    47% lit

    6.3 h

  29. 29

    37% lit

    6.6 h

  30. 30

    28% lit

    7.0 h

Each cell is the night that starts on that date. Hours are civil-dark time with the moon below the horizon; the green rule scales with them. Green outline: new moon. Bone outline: full moon.

Activity in past Aprils

Chicago needs Kp 8 for the average oval edge to sit overhead. 5 of the 900 April days from 1996 to 2025 (1%) reached it in the GFZ Potsdam record, 4th of 12 months; storm days with Kp 5 or more made up 12%. Chicago sits at 50.7 degrees geomagnetic. The lowest NOAA storm level whose typical viewing latitude reaches it is G3 (Kp = 7). By SWPC's rule the average oval edge is overhead only at Kp 8.

April across United States

No month-page town in United States has more civil night on April 15 than Chicago; the national median is 9.2 hours. Coming from March (11.1 hours at Chicago), April loses darkness, and May brings shorter nights (8.3 hours on the 15th).

Civil night on April 15 and April cloud, month-page towns in United States
TownCivil nightCloud
Chicago9.6 h63%
Buffalo9.5 h69%
Portland, Maine9.4 h62%
Minneapolis9.3 h61%
Duluth9.2 h64%
Fargo9.2 h61%
Seattle9.1 h75%
Juneau7.9 h75%
Anchorage7.4 h72%
Eagle River7.4 h72%
Fairbanks6.6 h59%

Darkness and moon, every night

Chicago, April 2027: each night from local noon to the next noon
NightCivilAstronomicalMoon-free darkMoon-free, 10 PM to 2 AMMoon lit
Thu Apr 110 h 14 min7 h 58 min8 h 46 min4 h22%
Fri Apr 210 h 11 min7 h 55 min9 h 7 min4 h14%
Sat Apr 310 h 9 min7 h 52 min9 h 27 min4 h8%
Sun Apr 410 h 6 min7 h 48 min9 h 46 min4 h4%
Mon Apr 510 h 3 min7 h 45 min10 h 3 min4 h1%
Tue Apr 610 h7 h 41 min10 h4 h0%
Wed Apr 79 h 57 min7 h 38 min9 h 16 min4 h2%
Thu Apr 89 h 54 min7 h 34 min8 h 1 min4 h6%
Fri Apr 99 h 51 min7 h 31 min6 h 45 min2 h 58 min12%
Sat Apr 109 h 48 min7 h 28 min5 h 33 min1 h 47 min21%
Sun Apr 119 h 46 min7 h 24 min4 h 29 min45 min31%
Mon Apr 129 h 43 min7 h 21 min3 h 35 min0 min42%
Tue Apr 139 h 40 min7 h 17 min2 h 51 min0 min53%
Wed Apr 149 h 37 min7 h 14 min2 h 16 min0 min64%
Thu Apr 159 h 34 min7 h 10 min1 h 46 min0 min75%
Fri Apr 169 h 31 min7 h 7 min1 h 20 min0 min84%
Sat Apr 179 h 28 min7 h 3 min55 min0 min91%
Sun Apr 189 h 26 min6 h 59 min30 min0 min96%
Mon Apr 199 h 23 min6 h 56 min4 min0 min99%
Tue Apr 209 h 20 min6 h 52 min0 min0 min100%
Wed Apr 219 h 17 min6 h 49 min52 min0 min98%
Thu Apr 229 h 14 min6 h 45 min1 h 59 min11 min94%
Fri Apr 239 h 12 min6 h 42 min3 h 1 min1 h 14 min89%
Sat Apr 249 h 9 min6 h 38 min3 h 56 min2 h 10 min82%
Sun Apr 259 h 6 min6 h 34 min4 h 42 min2 h 57 min74%
Mon Apr 269 h 3 min6 h 31 min5 h 19 min3 h 35 min65%
Tue Apr 279 h 1 min6 h 27 min5 h 50 min4 h56%
Wed Apr 288 h 58 min6 h 24 min6 h 15 min4 h47%
Thu Apr 298 h 55 min6 h 20 min6 h 37 min4 h37%
Fri Apr 308 h 53 min6 h 17 min6 h 57 min4 h28%
Moon lit: SunCalc illuminated fraction at the middle of the 10 PM to 2 AM window.

Questions

Can you see the northern lights in Chicago in April?
On dark, clear nights with enough activity. 30 of 30 nights at Chicago have civil darkness, and 1% of past April days reached Kp 8.
How dark is Chicago in April?
Chicago averages 9.5 hours of civil night a night in April 2027, from 10 h 14 min on the 1st to 8 h 53 min on the last night.
How cloudy is Chicago in April?
NASA POWER's 2001 to 2020 climatology gives Chicago's 1 degree cell 63% mean cloud in April, against 60% for the whole year. It is an all-hours average, not a forecast.
What is the best night in April 2027 for aurora in Chicago?
By darkness and moon alone, Apr 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Chicago. Activity on that date will only be known hours ahead.
Is April or May better in Chicago?
By civil night times the clear share, April scores 3.6 hours at Chicago and May 3.0. April comes out ahead.

Sources and verification

Quoted figures last checked against their sources on 2026-09-30; next review 2026-12-31. Computed figures come from SunCalc and the IGRF-14 dipole as described in the methodology. Every quote is listed in the sources ledger.