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Eau Claire · April 2027

Northern lights in Eau Claire in April 2027

Answer

April gives Eau Claire 9.4 hours of civil night on the 15th, the 8th darkest of its 12 months, under 63% mean cloud. 2% of April days since 1996 reached Kp 7, enough for the oval edge to reach Eau Claire.
9.3 h
civil night, average night
SunCalc for 44.81, -91.50; NASA POWER; GFZ Kp

April against the rest of the year

April cloud at Eau Claire averages 63% in NASA POWER's 2001 to 2020 record, 3 points cloudier than its yearly mean. July is Eau Claire's clearest month at 47%. By civil night times clear sky, April scores 3.5 hours at Eau Claire, 10th of 12. Minneapolis, 140 km away, averages 61%, clearer by 2 points.

Civil night at Eau Claire starts April at 10 h 7 min and reaches 8 h 36 min by April 30, 1.5 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 6.8 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. Eau Claire gets 147 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

    9.7 h

  5. 5

    1% lit

    9.9 h

  6. 6

    0% lit

    9.8 h

  7. 7

    2% lit

    9.1 h

  8. 8

    6% lit

    7.8 h

  9. 9

    12% lit

    6.5 h

  10. 10

    21% lit

    5.2 h

  11. 11

    31% lit

    4.2 h

  12. 12

    42% lit

    3.3 h

  13. 13

    53% lit

    2.6 h

  14. 14

    64% lit

    2.0 h

  15. 15

    75% lit

    1.6 h

  16. 16

    84% lit

    1.2 h

  17. 17

    91% lit

    0.8 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

    2.1 h

  23. 23

    89% lit

    3.1 h

  24. 24

    82% lit

    4.0 h

  25. 25

    74% lit

    4.8 h

  26. 26

    65% lit

    5.4 h

  27. 27

    56% lit

    5.8 h

  28. 28

    47% lit

    6.2 h

  29. 29

    37% lit

    6.6 h

  30. 30

    28% lit

    6.8 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

Eau Claire needs Kp 7 for the average oval edge to sit overhead. 19 of the 900 April days from 1996 to 2025 (2%) reached it in the GFZ Potsdam record, one of the three most active months for that level; storm days with Kp 5 or more made up 12%. Eau Claire sits at 53.4 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 7.

April across United States

Eau Claire ranks 2nd in United States for civil night on April 15, behind Buffalo at 9.5 hours. Coming from March (11.0 hours at Eau Claire), April loses darkness, and May brings shorter nights (7.9 hours on the 15th).

Civil night on April 15 and April cloud, month-page towns in United States
TownCivil nightCloud
Buffalo9.5 h69%
Eau Claire9.4 h63%
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

Eau Claire, 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 7 min7 h 42 min8 h 49 min4 h22%
Fri Apr 210 h 4 min7 h 39 min9 h 8 min4 h14%
Sat Apr 310 h7 h 35 min9 h 25 min4 h8%
Sun Apr 49 h 57 min7 h 31 min9 h 42 min4 h4%
Mon Apr 59 h 54 min7 h 27 min9 h 54 min4 h1%
Tue Apr 69 h 51 min7 h 23 min9 h 51 min4 h0%
Wed Apr 79 h 48 min7 h 19 min9 h 3 min4 h2%
Thu Apr 89 h 44 min7 h 15 min7 h 45 min3 h 46 min6%
Fri Apr 99 h 41 min7 h 11 min6 h 27 min2 h 30 min12%
Sat Apr 109 h 38 min7 h 7 min5 h 14 min1 h 18 min21%
Sun Apr 119 h 35 min7 h 4 min4 h 9 min15 min31%
Mon Apr 129 h 31 min7 h3 h 17 min0 min42%
Tue Apr 139 h 28 min6 h 56 min2 h 35 min0 min53%
Wed Apr 149 h 25 min6 h 52 min2 h 2 min0 min64%
Thu Apr 159 h 22 min6 h 47 min1 h 35 min0 min75%
Fri Apr 169 h 19 min6 h 43 min1 h 11 min0 min84%
Sat Apr 179 h 16 min6 h 39 min49 min0 min91%
Sun Apr 189 h 12 min6 h 35 min27 min0 min96%
Mon Apr 199 h 9 min6 h 31 min3 min0 min99%
Tue Apr 209 h 6 min6 h 27 min0 min0 min100%
Wed Apr 219 h 3 min6 h 23 min56 min0 min98%
Thu Apr 229 h6 h 19 min2 h 5 min39 min94%
Fri Apr 238 h 57 min6 h 15 min3 h 8 min1 h 44 min89%
Sat Apr 248 h 54 min6 h 11 min4 h 3 min2 h 40 min82%
Sun Apr 258 h 51 min6 h 6 min4 h 48 min3 h 26 min74%
Mon Apr 268 h 48 min6 h 2 min5 h 23 min4 h65%
Tue Apr 278 h 45 min5 h 58 min5 h 51 min4 h56%
Wed Apr 288 h 41 min5 h 54 min6 h 14 min4 h47%
Thu Apr 298 h 38 min5 h 50 min6 h 34 min4 h37%
Fri Apr 308 h 36 min5 h 45 min6 h 51 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 Eau Claire in April?
On dark, clear nights with enough activity. 30 of 30 nights at Eau Claire have civil darkness, and 2% of past April days reached Kp 7.
How dark is Eau Claire in April?
Eau Claire averages 9.3 hours of civil night a night in April 2027, from 10 h 7 min on the 1st to 8 h 36 min on the last night.
How cloudy is Eau Claire in April?
NASA POWER's 2001 to 2020 climatology gives Eau Claire'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 Eau Claire?
By darkness and moon alone, Apr 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Eau Claire. Activity on that date will only be known hours ahead.
Is April or May better in Eau Claire?
By civil night times the clear share, April scores 3.5 hours at Eau Claire and May 2.9. 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.