Can you see the northern lights in Udachny in September?

On dark, clear nights with enough activity. 30 of 30 nights at Udachny have civil darkness, and 14% of past September days reached Kp 5.

How dark is Udachny in September?

Udachny averages 8.9 hours of civil night a night in September 2027, from 6 h 56 min on the 1st to 10 h 43 min on the last night.

How cloudy is Udachny in September?

NASA POWER's 2001 to 2020 climatology gives Udachny's 1 degree cell 76% mean cloud in September, against 60% for the whole year. It is an all-hours average, not a forecast.

What is the best night in September 2027 for aurora in Udachny?

By darkness and moon alone, Sep 2, with 4 h of moon-free darkness inside 10 PM to 2 AM at Udachny. Activity on that date will only be known hours ahead.

Is September or October better in Udachny?

By civil night times the clear share, September scores 2.1 hours at Udachny and October 2.1. September comes out ahead.

Udachny · September 2027

Northern lights in Udachny in September 2027

Answer

September gives Udachny 8.9 hours of civil night on the 15th, the 7th darkest of its 12 months, under 76% mean cloud. 14% of September days since 1996 reached Kp 5, enough for the oval edge to reach Udachny.

8.9 h

civil night, average night

SunCalc for 66.43, 112.40; NASA POWER; GFZ Kp

September against the rest of the year

9.7

8.2

5.6

2.3

0.0

1.2

2.1

6.8

10.4

September cloud at Udachny averages 76% in NASA POWER's 2001 to 2020 record, 16 points cloudier than its yearly mean. February is Udachny's clearest month at 40%. By civil night times clear sky, September scores 2.1 hours at Udachny, 7th of 12. Talnakh, 1,050 km away, averages 82%, cloudier by 6 points.

Civil night at Udachny starts September at 6 h 56 min and reaches 10 h 43 min by September 30 as the nights lengthen by 3.8 hours. The 10 PM to 2 AM window is fully dark on 29 of 30 nights. True astronomical darkness, the sun 18 degrees down, lasts 3.3 hours on the 15th.

September night by night

September opens toward a new moon on Sep 1 and Sep 30, with full moon on Sep 16, in Asia/Yakutsk dates. Udachny gets 135 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 2 (4 h), Sep 3 (4 h), Sep 4 (4 h).

1
1% lit
6.9 h
New
2
5% lit
7.1 h
3
12% lit
7.2 h
4
20% lit
7.4 h
5
29% lit
7.5 h
6
39% lit
7.7 h
7
49% lit
7.8 h
8
58% lit
7.9 h
9
68% lit
8.1 h
10
76% lit
8.2 h
11
84% lit
5.4 h
12
90% lit
3.5 h
13
95% lit
1.8 h
14
98% lit
0.1 h
15
100% lit
0.0 h
16
99% lit
0.0 h
Full
17
97% lit
0.0 h
18
93% lit
0.0 h
19
87% lit
0.0 h
20
79% lit
0.0 h
21
69% lit
0.0 h
22
59% lit
0.0 h
23
48% lit
0.0 h
24
37% lit
0.0 h
25
26% lit
3.3 h
26
16% lit
5.7 h
27
9% lit
7.9 h
28
3% lit
10.0 h
29
0% lit
10.6 h
30
1% lit
10.7 h
New

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

Udachny needs Kp 5 for the average oval edge to sit overhead. 126 of the 900 September days from 1996 to 2025 (14%) 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%. Udachny sits at 57.2 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 5, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less.

September across Russia

Udachny ranks 12th in Russia for civil night on September 15, behind Velikiy Novgorod at 9.7 hours. Coming from August (4.1 hours at Udachny), September adds darkness, and the nights keep growing into October (12.5 hours on the 15th). The September equinox falls on September 23, 14:56 Udachny time, inside the weeks SWPC links with larger storms.

Civil night on September 15 and September cloud, month-page towns in Russia
Town	Civil night	Cloud
Velikiy Novgorod	9.7 h	68%
Saint Petersburg	9.6 h	70%
Kolpino	9.6 h	70%
Syktyvkar	9.5 h	76%
Petrozavodsk	9.4 h	74%
Noyabrsk	9.3 h	77%
Ukhta	9.3 h	78%
Arkhangel'sk	9.2 h	76%
Severodvinsk	9.2 h	76%
Kostomuksha	9.2 h	74%
Anadyr	9.1 h	69%
Udachny	8.9 h	76%

Darkness and moon, every night

Udachny, September 2027: each night from local noon to the next noon
Night	Civil	Astronomical	Moon-free dark	Moon-free, 10 PM to 2 AM	Moon lit
Wed Sep 1	6 h 56 min	0 min	6 h 56 min	3 h 57 min	1%
Thu Sep 2	7 h 5 min	0 min	7 h 5 min	4 h	5%
Fri Sep 3	7 h 14 min	0 min	7 h 14 min	4 h	12%
Sat Sep 4	7 h 22 min	0 min	7 h 22 min	4 h	20%
Sun Sep 5	7 h 31 min	0 min	7 h 31 min	4 h	29%
Mon Sep 6	7 h 39 min	0 min	7 h 39 min	4 h	39%
Tue Sep 7	7 h 47 min	0 min	7 h 47 min	4 h	49%
Wed Sep 8	7 h 55 min	0 min	7 h 55 min	4 h	58%
Thu Sep 9	8 h 4 min	0 min	8 h 4 min	4 h	68%
Fri Sep 10	8 h 12 min	1 h 5 min	8 h 12 min	4 h	76%
Sat Sep 11	8 h 20 min	1 h 45 min	5 h 26 min	1 h 48 min	84%
Sun Sep 12	8 h 28 min	2 h 13 min	3 h 27 min	0 min	90%
Mon Sep 13	8 h 36 min	2 h 36 min	1 h 45 min	0 min	95%
Tue Sep 14	8 h 43 min	2 h 56 min	9 min	0 min	98%
Wed Sep 15	8 h 51 min	3 h 15 min	0 min	0 min	100%
Thu Sep 16	8 h 59 min	3 h 31 min	0 min	0 min	99%
Fri Sep 17	9 h 7 min	3 h 47 min	0 min	0 min	97%
Sat Sep 18	9 h 14 min	4 h 2 min	0 min	0 min	93%
Sun Sep 19	9 h 22 min	4 h 16 min	0 min	0 min	87%
Mon Sep 20	9 h 29 min	4 h 29 min	0 min	0 min	79%
Tue Sep 21	9 h 37 min	4 h 41 min	0 min	0 min	69%
Wed Sep 22	9 h 44 min	4 h 54 min	0 min	0 min	59%
Thu Sep 23	9 h 52 min	5 h 5 min	0 min	0 min	48%
Fri Sep 24	9 h 59 min	5 h 17 min	0 min	0 min	37%
Sat Sep 25	10 h 7 min	5 h 28 min	3 h 17 min	1 h 37 min	26%
Sun Sep 26	10 h 14 min	5 h 38 min	5 h 43 min	3 h 58 min	16%
Mon Sep 27	10 h 21 min	5 h 49 min	7 h 54 min	4 h	9%
Tue Sep 28	10 h 29 min	5 h 59 min	9 h 58 min	4 h	3%
Wed Sep 29	10 h 36 min	6 h 9 min	10 h 36 min	4 h	0%
Thu Sep 30	10 h 43 min	6 h 18 min	10 h 43 min	4 h	1%

Moon lit: SunCalc illuminated fraction at the middle of the 10 PM to 2 AM window.

Questions

Can you see the northern lights in Udachny in September?: On dark, clear nights with enough activity. 30 of 30 nights at Udachny have civil darkness, and 14% of past September days reached Kp 5.
How dark is Udachny in September?: Udachny averages 8.9 hours of civil night a night in September 2027, from 6 h 56 min on the 1st to 10 h 43 min on the last night.
How cloudy is Udachny in September?: NASA POWER's 2001 to 2020 climatology gives Udachny's 1 degree cell 76% mean cloud in September, against 60% for the whole year. It is an all-hours average, not a forecast.
What is the best night in September 2027 for aurora in Udachny?: By darkness and moon alone, Sep 2, with 4 h of moon-free darkness inside 10 PM to 2 AM at Udachny. Activity on that date will only be known hours ahead.
Is September or October better in Udachny?: By civil night times the clear share, September scores 2.1 hours at Udachny and October 2.1. September comes out ahead.

Sources and verification

SunCalchttps://github.com/mourner/suncalc
NASA POWER climatologyhttps://power.larc.nasa.gov/docs/services/api/temporal/climatology/
GFZ Potsdam Kp indexhttps://kp.gfz.de/en/data
NOAA SWPC, Tips on viewing the aurorahttps://www.spaceweather.gov/content/tips-viewing-aurora

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.