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Valley East · September 2027

Northern lights in Valley East in September 2027

Answer

September gives Valley East 10.4 hours of civil night on the 15th, the 7th darkest of its 12 months, under 58% mean cloud. 5% of September days since 1996 reached Kp 6, enough for the oval edge to reach Valley East.
10.4 h
civil night, average night
SunCalc for 46.65, -81.00; NASA POWER; GFZ Kp

September against the rest of the year

September cloud at Valley East averages 58% in NASA POWER's 2001 to 2020 record, 7 points clearer than its yearly mean. July is Valley East's clearest month at 54%. By civil night times clear sky, September scores 4.4 hours at Valley East, 2nd of 12. Greater Sudbury, 17 km away, averages the same 58%.

Civil night at Valley East starts September at 9 h 33 min and reaches 11 h 11 min by September 30 as the nights lengthen by 1.6 hours. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 7.9 hours on the 15th.

September night by night

Full moon comes first, on Sep 15, then the new moon on Sep 29, in America/Toronto dates. Valley East gets 157 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: Sep 1 (4 h), Sep 2 (4 h), Sep 3 (4 h).

  1. 1

    3% lit

    9.6 h

  2. 2

    8% lit

    9.6 h

  3. 3

    16% lit

    9.3 h

  4. 4

    25% lit

    8.9 h

  5. 5

    34% lit

    8.4 h

  6. 6

    44% lit

    7.8 h

  7. 7

    54% lit

    7.1 h

  8. 8

    64% lit

    6.2 h

  9. 9

    72% lit

    5.2 h

  10. 10

    80% lit

    4.1 h

  11. 11

    87% lit

    3.0 h

  12. 12

    93% lit

    1.9 h

  13. 13

    97% lit

    0.9 h

  14. 14

    99% lit

    0.0 h

  15. 15

    100% lit

    0.0 h

  16. 16

    98% lit

    0.0 h

  17. 17

    95% lit

    0.0 h

  18. 18

    90% lit

    0.1 h

  19. 19

    83% lit

    0.6 h

  20. 20

    74% lit

    1.2 h

  21. 21

    64% lit

    2.0 h

  22. 22

    53% lit

    3.0 h

  23. 23

    42% lit

    4.1 h

  24. 24

    31% lit

    5.5 h

  25. 25

    21% lit

    6.9 h

  26. 26

    12% lit

    8.3 h

  27. 27

    5% lit

    9.7 h

  28. 28

    1% lit

    11.1 h

  29. 29

    0% lit

    11.1 h

  30. 30

    2% lit

    11.2 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 Septembers

Valley East needs Kp 6 for the average oval edge to sit overhead. 47 of the 900 September days from 1996 to 2025 (5%) 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 14%. Valley East sits at 55.7 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 6, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less.

September across Canada

No month-page town in Canada has more civil night on September 15 than Valley East; the national median is 10.2 hours. Coming from August (8.6 hours at Valley East), September adds darkness, and the nights keep growing into October (12.0 hours on the 15th). The September equinox falls on September 23, 01:56 Valley East time, inside the weeks SWPC links with larger storms.

Civil night on September 15 and September cloud, month-page towns in Canada
TownCivil nightCloud
Valley East10.4 h58%
Québec10.4 h57%
Greater Sudbury10.4 h58%
Trois-Rivières10.4 h56%
Sydney10.4 h64%
Saguenay10.3 h65%
St. John's10.3 h69%
Thunder Bay10.3 h65%
Calgary10.2 h62%
Winnipeg10.2 h55%
Regina10.2 h55%
Kelowna10.2 h53%

Darkness and moon, every night

Valley East, September 2027: each night from local noon to the next noon
NightCivilAstronomicalMoon-free darkMoon-free, 10 PM to 2 AMMoon lit
Wed Sep 19 h 33 min6 h 56 min9 h 33 min4 h3%
Thu Sep 29 h 36 min7 h 1 min9 h 36 min4 h8%
Fri Sep 39 h 40 min7 h 5 min9 h 20 min4 h16%
Sat Sep 49 h 43 min7 h 9 min8 h 56 min4 h25%
Sun Sep 59 h 47 min7 h 13 min8 h 27 min4 h34%
Mon Sep 69 h 50 min7 h 17 min7 h 50 min3 h 33 min44%
Tue Sep 79 h 53 min7 h 21 min7 h 5 min2 h 46 min54%
Wed Sep 89 h 57 min7 h 25 min6 h 12 min1 h 51 min64%
Thu Sep 910 h7 h 29 min5 h 11 min50 min72%
Fri Sep 1010 h 4 min7 h 33 min4 h 7 min0 min80%
Sat Sep 1110 h 7 min7 h 37 min3 h 2 min0 min87%
Sun Sep 1210 h 10 min7 h 41 min1 h 57 min0 min93%
Mon Sep 1310 h 14 min7 h 45 min53 min0 min97%
Tue Sep 1410 h 17 min7 h 49 min0 min0 min99%
Wed Sep 1510 h 20 min7 h 53 min0 min0 min100%
Thu Sep 1610 h 24 min7 h 57 min0 min0 min98%
Fri Sep 1710 h 27 min8 h 1 min0 min0 min95%
Sat Sep 1810 h 31 min8 h 5 min8 min0 min90%
Sun Sep 1910 h 34 min8 h 8 min36 min0 min83%
Mon Sep 2010 h 37 min8 h 12 min1 h 12 min0 min74%
Tue Sep 2110 h 41 min8 h 16 min1 h 58 min0 min64%
Wed Sep 2210 h 44 min8 h 20 min2 h 57 min52 min53%
Thu Sep 2310 h 47 min8 h 23 min4 h 8 min2 h 1 min42%
Fri Sep 2410 h 51 min8 h 27 min5 h 29 min3 h 20 min31%
Sat Sep 2510 h 54 min8 h 31 min6 h 53 min4 h21%
Sun Sep 2610 h 57 min8 h 34 min8 h 18 min4 h12%
Mon Sep 2711 h 1 min8 h 38 min9 h 42 min4 h5%
Tue Sep 2811 h 4 min8 h 42 min11 h 4 min4 h1%
Wed Sep 2911 h 7 min8 h 45 min11 h 7 min4 h0%
Thu Sep 3011 h 11 min8 h 49 min11 h 11 min4 h2%
Moon lit: SunCalc illuminated fraction at the middle of the 10 PM to 2 AM window.

Questions

Can you see the northern lights in Valley East in September?
On dark, clear nights with enough activity. 30 of 30 nights at Valley East have civil darkness, and 5% of past September days reached Kp 6.
How dark is Valley East in September?
Valley East averages 10.4 hours of civil night a night in September 2027, from 9 h 33 min on the 1st to 11 h 11 min on the last night.
How cloudy is Valley East in September?
NASA POWER's 2001 to 2020 climatology gives Valley East's 1 degree cell 58% mean cloud in September, against 65% for the whole year. It is an all-hours average, not a forecast.
What is the best night in September 2027 for aurora in Valley East?
By darkness and moon alone, Sep 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Valley East. Activity on that date will only be known hours ahead.
Is September or October better in Valley East?
By civil night times the clear share, September scores 4.4 hours at Valley East and October 3.6. September 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.