Is September good for the northern lights?

SWPC names the fall equinox season as one of the best for aurora, and the far north gains darkness quickly this month.

Which town has the longest nights in September?

Buffalo, with 10 h 28 min of civil night on September 15, 2027, of the 10 Glow towns.

When is the full moon in September 2027?

On September 15, 2027 (UTC date). Local dates can differ by a day.

Does September have an equinox or solstice?

Yes, the September equinox, on September 23, 05:56 UTC.

How many Glow towns are dark in September?

10 of 10 have civil night on September 15, 2027.

Aurora by month · 2027

Northern lights in September

Answer

September holds the fall equinox, the other season SWPC calls best for aurora watching. On September 15, 2027, Buffalo has the most civil night of the 10 Glow towns at 10 h 28 min, and Tromsø the least at 8 h 22 min. The median is 9.9 hours.

Best destinations in September

Across Glow's 168 month-page towns, Minneapolis scores highest for September at 5.3 clear-dark hours: 10.4 hours of civil night on the 15th with 49% mean cloud. The median town scores 2.6. The score multiplies civil night by the clear share of NASA POWER's 2001 to 2020 cloud average; it compares places, it does not forecast.

Top 20 month-page towns for September, by civil night times clear share
Town	Country	Civil night	Cloud	Score
Minneapolis	United States	10.4 h	49%	5.3 h
Portland, Maine	United States	10.5 h	50%	5.3 h
Fargo	United States	10.4 h	50%	5.2 h
Seattle	United States	10.3 h	53%	4.8 h
Kelowna	Canada	10.2 h	53%	4.8 h
Winnipeg	Canada	10.2 h	55%	4.6 h
Regina	Canada	10.2 h	55%	4.6 h
Duluth	United States	10.4 h	56%	4.6 h
Trois-Rivières	Canada	10.4 h	56%	4.6 h
Buffalo	United States	10.5 h	57%	4.5 h
Lethbridge	Canada	10.2 h	56%	4.5 h
Québec	Canada	10.4 h	57%	4.5 h
Greater Sudbury	Canada	10.4 h	58%	4.4 h
Kamloops	Canada	10.2 h	58%	4.3 h
Saskatoon	Canada	10.1 h	58%	4.2 h
Lloydminster	Canada	10.1 h	59%	4.1 h
Edmonton	Canada	10.1 h	60%	4.0 h
Red Deer	Canada	10.1 h	61%	3.9 h
Calgary	Canada	10.2 h	62%	3.9 h
Odense	Denmark	9.9 h	62%	3.8 h

All 168 towns in September

September 2027 at 10 towns

Civil night on the 1st, 15th and last night of September 2027, with astronomical night and moon-free darkness on the 15th
Town	Sep 1	Sep 15	Last night	Astronomical, 15th
Buffalo	9 h 47 min	10 h 28 min	11 h 12 min	8 h 12 min
Portland, Maine	9 h 44 min	10 h 27 min	11 h 12 min	8 h 8 min
Minneapolis	9 h 40 min	10 h 24 min	11 h 11 min	8 h 2 min
Duluth	9 h 33 min	10 h 20 min	11 h 11 min	7 h 52 min
Seattle	9 h 30 min	10 h 19 min	11 h 10 min	7 h 48 min
Anchorage	8 h 5 min	9 h 31 min	10 h 58 min	5 h 36 min
Yellowknife	7 h 52 min	9 h 24 min	10 h 56 min	5 h 13 min
Reykjavik	7 h 31 min	9 h 11 min	10 h 51 min	4 h 33 min
Fairbanks	7 h 25 min	9 h 9 min	10 h 52 min	4 h 18 min
Tromsø	5 h 57 min	8 h 22 min	10 h 35 min	0 min

Civil night: sun at or below -6 degrees; astronomical: -18. Each town links to its full month page with every night.

What September means for aurora

SWPC's equinox tendency toward larger storms applies again around the September equinox, and this time the far north is gaining darkness fast instead of losing it. The lower 48 towns pass 10 hours of civil night by mid-month.

Tromsø changes fastest across September: 5 h 57 min of civil night on the 1st and 10 h 35 min on the last night, a gain of 4.6 hours. The September equinox falls on September 23, 05:56 UTC.

The moon in September 2027

In UTC dates, the new moon falls on Sep 30 and the full moon on Sep 15. Local dates can differ by a day; each town's month page uses its own time zone.

SWPC says a full moon diminishes the apparent brightness of the aurora. Nights near the new moon give the darkest background. The moon planner shows every night of September for any coordinates, and the moon guide explains how Glow counts moon-free darkness.

Questions

Is September good for the northern lights?: SWPC names the fall equinox season as one of the best for aurora, and the far north gains darkness quickly this month.
Which town has the longest nights in September?: Buffalo, with 10 h 28 min of civil night on September 15, 2027, of the 10 Glow towns.
When is the full moon in September 2027?: On September 15, 2027 (UTC date). Local dates can differ by a day.
Does September have an equinox or solstice?: Yes, the September equinox, on September 23, 05:56 UTC.
How many Glow towns are dark in September?: 10 of 10 have civil night on September 15, 2027.

Sources and verification

SunCalchttps://github.com/mourner/suncalc
NOAA SWPC, Tips on viewing the aurorahttps://www.spaceweather.gov/content/tips-viewing-aurora
NOAA SWPC, Aurorahttps://www.swpc.noaa.gov/phenomena/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.