Can you see the northern lights in Tri-Cities in October?

On dark, clear nights with enough activity. 31 of 31 nights at Tri-Cities have civil darkness, and 2% of past October days reached Kp 7.

How dark is Tri-Cities in October?

Tri-Cities averages 12.0 hours of civil night a night in October 2026, from 11 h 15 min on the 1st to 12 h 46 min on the last night.

How cloudy is Tri-Cities in October?

NASA POWER's 2001 to 2020 climatology gives Tri-Cities's 1 degree cell 56% mean cloud in October, against 56% for the whole year. It is an all-hours average, not a forecast.

What is the best night in October 2026 for aurora in Tri-Cities?

By darkness and moon alone, Oct 5, with 4 h of moon-free darkness inside 10 PM to 2 AM at Tri-Cities. Activity on that date will only be known hours ahead.

Is October or November better in Tri-Cities?

By civil night times the clear share, October scores 5.3 hours at Tri-Cities and November 4.0. October comes out ahead.

Tri-Cities · October 2026

Northern lights in Tri-Cities in October 2026

Answer

October gives Tri-Cities 12.0 hours of civil night on the 15th, the 5th darkest of its 12 months, under 56% mean cloud. 2% of October days since 1996 reached Kp 7, enough for the oval edge to reach Tri-Cities.

12.0 h

civil night, average night

SunCalc for 46.25, -119.20; NASA POWER; GFZ Kp

October against the rest of the year

2.9

4.0

3.4

3.6

3.4

3.7

5.4

6.2

6.3

5.3

4.0

3.2

October cloud at Tri-Cities averages 56% in NASA POWER's 2001 to 2020 record, close to its yearly mean of 56%. July is Tri-Cities's clearest month at 26%. By civil night times clear sky, October scores 5.3 hours at Tri-Cities, 4th of 12. Seattle, 282 km away, averages 68%, cloudier by 12 points.

Civil night at Tri-Cities starts October at 11 h 15 min and reaches 12 h 46 min by October 31 as the nights lengthen by 1.5 hours. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 9.7 hours on the 15th.

October night by night

October opens toward a new moon on Oct 10, with full moon on Oct 25, in America/Los_Angeles dates. Tri-Cities gets 185 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: Oct 5 (4 h), Oct 6 (4 h), Oct 7 (4 h).

1
64% lit
2.2 h
2
53% lit
3.3 h
3
42% lit
4.6 h
4
31% lit
6.0 h
5
21% lit
7.3 h
6
13% lit
8.7 h
7
6% lit
9.9 h
8
2% lit
11.2 h
9
0% lit
11.7 h
10
1% lit
11.7 h
New
11
3% lit
11.8 h
12
7% lit
11.8 h
13
13% lit
11.4 h
14
20% lit
10.8 h
15
28% lit
10.1 h
16
37% lit
9.1 h
17
46% lit
8.1 h
18
56% lit
7.0 h
19
65% lit
5.9 h
20
74% lit
4.8 h
21
83% lit
3.6 h
22
90% lit
2.4 h
23
95% lit
1.2 h
24
99% lit
0.0 h
25
100% lit
0.0 h
Full
26
98% lit
0.0 h
27
94% lit
0.0 h
28
87% lit
0.9 h
29
78% lit
1.9 h
30
68% lit
3.2 h
31
56% lit
4.6 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 Octobers

Tri-Cities needs Kp 7 for the average oval edge to sit overhead. 22 of the 930 October 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%. Tri-Cities sits at 52.1 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.

October across United States

Tri-Cities ranks 5th in United States for civil night on October 15, behind Fairbanks at 12.5 hours. Coming from September (10.4 hours at Tri-Cities), October adds darkness, and the nights keep growing into November (13.4 hours on the 15th).

Civil night on October 15 and October cloud, month-page towns in United States
Town	Civil night	Cloud
Fairbanks	12.5 h	77%
Anchorage	12.4 h	77%
Eagle River	12.4 h	77%
Juneau	12.3 h	81%
Tri-Cities	12.0 h	56%
Seattle	12.0 h	68%
Minneapolis	12.0 h	59%
Duluth	12.0 h	64%
Fargo	12.0 h	60%
Buffalo	11.9 h	70%
Portland, Maine	11.9 h	59%

Darkness and moon, every night

Tri-Cities, October 2026: each night from local noon to the next noon
Night	Civil	Astronomical	Moon-free dark	Moon-free, 10 PM to 2 AM	Moon lit
Thu Oct 1	11 h 15 min	8 h 55 min	2 h 12 min	0 min	64%
Fri Oct 2	11 h 18 min	8 h 58 min	3 h 20 min	27 min	53%
Sat Oct 3	11 h 22 min	9 h 1 min	4 h 37 min	1 h 43 min	42%
Sun Oct 4	11 h 25 min	9 h 5 min	5 h 59 min	3 h 3 min	31%
Mon Oct 5	11 h 28 min	9 h 8 min	7 h 21 min	4 h	21%
Tue Oct 6	11 h 31 min	9 h 12 min	8 h 40 min	4 h	13%
Wed Oct 7	11 h 34 min	9 h 15 min	9 h 57 min	4 h	6%
Thu Oct 8	11 h 37 min	9 h 18 min	11 h 12 min	4 h	2%
Fri Oct 9	11 h 41 min	9 h 21 min	11 h 41 min	4 h	0%
Sat Oct 10	11 h 44 min	9 h 25 min	11 h 44 min	4 h	1%
Sun Oct 11	11 h 47 min	9 h 28 min	11 h 47 min	4 h	3%
Mon Oct 12	11 h 50 min	9 h 31 min	11 h 50 min	4 h	7%
Tue Oct 13	11 h 53 min	9 h 34 min	11 h 26 min	4 h	13%
Wed Oct 14	11 h 56 min	9 h 37 min	10 h 49 min	4 h	20%
Thu Oct 15	11 h 59 min	9 h 40 min	10 h 3 min	4 h	28%
Fri Oct 16	12 h 2 min	9 h 43 min	9 h 8 min	4 h	37%
Sat Oct 17	12 h 5 min	9 h 46 min	8 h 6 min	3 h 21 min	46%
Sun Oct 18	12 h 8 min	9 h 49 min	7 h 1 min	2 h 14 min	56%
Mon Oct 19	12 h 12 min	9 h 52 min	5 h 53 min	1 h 5 min	65%
Tue Oct 20	12 h 15 min	9 h 55 min	4 h 45 min	0 min	74%
Wed Oct 21	12 h 18 min	9 h 58 min	3 h 36 min	0 min	83%
Thu Oct 22	12 h 20 min	10 h 1 min	2 h 25 min	0 min	90%
Fri Oct 23	12 h 23 min	10 h 4 min	1 h 12 min	0 min	95%
Sat Oct 24	12 h 26 min	10 h 7 min	0 min	0 min	99%
Sun Oct 25	12 h 29 min	10 h 10 min	0 min	0 min	100%
Mon Oct 26	12 h 32 min	10 h 12 min	0 min	0 min	98%
Tue Oct 27	12 h 35 min	10 h 15 min	2 min	0 min	94%
Wed Oct 28	12 h 38 min	10 h 18 min	52 min	0 min	87%
Thu Oct 29	12 h 41 min	10 h 21 min	1 h 57 min	0 min	78%
Fri Oct 30	12 h 43 min	10 h 23 min	3 h 13 min	0 min	68%
Sat Oct 31	12 h 46 min	10 h 26 min	4 h 35 min	52 min	56%

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

Questions

Can you see the northern lights in Tri-Cities in October?: On dark, clear nights with enough activity. 31 of 31 nights at Tri-Cities have civil darkness, and 2% of past October days reached Kp 7.
How dark is Tri-Cities in October?: Tri-Cities averages 12.0 hours of civil night a night in October 2026, from 11 h 15 min on the 1st to 12 h 46 min on the last night.
How cloudy is Tri-Cities in October?: NASA POWER's 2001 to 2020 climatology gives Tri-Cities's 1 degree cell 56% mean cloud in October, against 56% for the whole year. It is an all-hours average, not a forecast.
What is the best night in October 2026 for aurora in Tri-Cities?: By darkness and moon alone, Oct 5, with 4 h of moon-free darkness inside 10 PM to 2 AM at Tri-Cities. Activity on that date will only be known hours ahead.
Is October or November better in Tri-Cities?: By civil night times the clear share, October scores 5.3 hours at Tri-Cities and November 4.0. October 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.