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

On dark, clear nights with enough activity. 31 of 31 nights at Tri-Cities have civil darkness, and 1% of past August days reached Kp 7.

How dark is Tri-Cities in August?

Tri-Cities averages 8.7 hours of civil night a night in August 2027, from 7 h 57 min on the 1st to 9 h 32 min on the last night.

How cloudy is Tri-Cities in August?

NASA POWER's 2001 to 2020 climatology gives Tri-Cities's 1 degree cell 29% mean cloud in August, against 56% for the whole year. It is an all-hours average, not a forecast.

What is the best night in August 2027 for aurora in Tri-Cities?

By darkness and moon alone, Aug 1, 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 August or September better in Tri-Cities?

By civil night times the clear share, August scores 6.2 hours at Tri-Cities and September 6.3. September comes out ahead.

Tri-Cities · August 2027

Northern lights in Tri-Cities in August 2027

Answer

August gives Tri-Cities 8.7 hours of civil night on the 15th, the 9th darkest of its 12 months, under 29% mean cloud. 1% of August days since 1996 reached Kp 7, enough for the oval edge to reach Tri-Cities.

8.7 h

civil night, average night

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

August 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

August cloud at Tri-Cities averages 29% in NASA POWER's 2001 to 2020 record, 27 points clearer than its yearly mean. July is Tri-Cities's clearest month at 26%. By civil night times clear sky, August scores 6.2 hours at Tri-Cities, 2nd of 12. Seattle, 282 km away, averages 48%, cloudier by 19 points.

Civil night at Tri-Cities starts August at 7 h 57 min and reaches 9 h 32 min by August 31 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 5.8 hours on the 15th.

August night by night

August opens toward a new moon on Aug 2 and Aug 31, with full moon on Aug 17, in America/Los_Angeles dates. Tri-Cities gets 136 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: Aug 1 (4 h), Aug 2 (4 h), Aug 3 (4 h).

1
0% lit
8.0 h
2
1% lit
8.0 h
New
3
5% lit
8.0 h
4
12% lit
7.7 h
5
20% lit
7.4 h
6
30% lit
7.1 h
7
41% lit
6.7 h
8
51% lit
6.3 h
9
61% lit
5.7 h
10
71% lit
5.1 h
11
79% lit
4.3 h
12
86% lit
3.3 h
13
92% lit
2.3 h
14
96% lit
1.2 h
15
99% lit
0.1 h
16
100% lit
0.0 h
17
99% lit
0.0 h
Full
18
96% lit
0.0 h
19
92% lit
0.1 h
20
86% lit
0.5 h
21
78% lit
0.8 h
22
69% lit
1.2 h
23
59% lit
1.7 h
24
48% lit
2.4 h
25
37% lit
3.3 h
26
26% lit
4.4 h
27
17% lit
5.7 h
28
9% lit
7.1 h
29
3% lit
8.6 h
30
0% lit
9.5 h
31
1% lit
9.5 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 Augusts

Tri-Cities needs Kp 7 for the average oval edge to sit overhead. 12 of the 930 August days from 1996 to 2025 (1%) reached it in the GFZ Potsdam record, 6th of 12 months; storm days with Kp 5 or more made up 11%. 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.

August across United States

Tri-Cities ranks 4th in United States for civil night on August 15, behind Buffalo at 9.0 hours. Coming from July (7.3 hours at Tri-Cities), August adds darkness, and the nights keep growing into September (10.4 hours on the 15th).

Civil night on August 15 and August cloud, month-page towns in United States
Town	Civil night	Cloud
Buffalo	9.0 h	56%
Portland, Maine	8.9 h	52%
Minneapolis	8.8 h	49%
Tri-Cities	8.7 h	29%
Duluth	8.6 h	52%
Fargo	8.6 h	49%
Seattle	8.5 h	48%
Juneau	6.9 h	79%
Anchorage	6.3 h	79%
Eagle River	6.2 h	79%
Fairbanks	5.0 h	75%

Darkness and moon, every night

Tri-Cities, August 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
Sun Aug 1	7 h 57 min	4 h 42 min	7 h 57 min	4 h	0%
Mon Aug 2	7 h 59 min	4 h 47 min	7 h 59 min	4 h	1%
Tue Aug 3	8 h 2 min	4 h 51 min	8 h 2 min	4 h	5%
Wed Aug 4	8 h 5 min	4 h 56 min	7 h 42 min	4 h	12%
Thu Aug 5	8 h 8 min	5 h 1 min	7 h 23 min	4 h	20%
Fri Aug 6	8 h 11 min	5 h 5 min	7 h 4 min	3 h 55 min	30%
Sat Aug 7	8 h 14 min	5 h 10 min	6 h 42 min	3 h 32 min	41%
Sun Aug 8	8 h 17 min	5 h 14 min	6 h 16 min	3 h 4 min	51%
Mon Aug 9	8 h 20 min	5 h 19 min	5 h 44 min	2 h 31 min	61%
Tue Aug 10	8 h 23 min	5 h 24 min	5 h 4 min	1 h 50 min	71%
Wed Aug 11	8 h 27 min	5 h 28 min	4 h 15 min	1 h	79%
Thu Aug 12	8 h 30 min	5 h 33 min	3 h 19 min	2 min	86%
Fri Aug 13	8 h 33 min	5 h 37 min	2 h 17 min	0 min	92%
Sat Aug 14	8 h 36 min	5 h 42 min	1 h 13 min	0 min	96%
Sun Aug 15	8 h 39 min	5 h 46 min	8 min	0 min	99%
Mon Aug 16	8 h 42 min	5 h 51 min	0 min	0 min	100%
Tue Aug 17	8 h 46 min	5 h 55 min	0 min	0 min	99%
Wed Aug 18	8 h 49 min	6 h	0 min	0 min	96%
Thu Aug 19	8 h 52 min	6 h 4 min	8 min	0 min	92%
Fri Aug 20	8 h 55 min	6 h 9 min	27 min	0 min	86%
Sat Aug 21	8 h 59 min	6 h 13 min	48 min	0 min	78%
Sun Aug 22	9 h 2 min	6 h 17 min	1 h 13 min	0 min	69%
Mon Aug 23	9 h 5 min	6 h 22 min	1 h 44 min	11 min	59%
Tue Aug 24	9 h 8 min	6 h 26 min	2 h 24 min	49 min	48%
Wed Aug 25	9 h 12 min	6 h 30 min	3 h 16 min	1 h 40 min	37%
Thu Aug 26	9 h 15 min	6 h 35 min	4 h 23 min	2 h 44 min	26%
Fri Aug 27	9 h 18 min	6 h 39 min	5 h 42 min	4 h	17%
Sat Aug 28	9 h 22 min	6 h 43 min	7 h 8 min	4 h	9%
Sun Aug 29	9 h 25 min	6 h 47 min	8 h 36 min	4 h	3%
Mon Aug 30	9 h 28 min	6 h 52 min	9 h 28 min	4 h	0%
Tue Aug 31	9 h 32 min	6 h 56 min	9 h 32 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 Tri-Cities in August?: On dark, clear nights with enough activity. 31 of 31 nights at Tri-Cities have civil darkness, and 1% of past August days reached Kp 7.
How dark is Tri-Cities in August?: Tri-Cities averages 8.7 hours of civil night a night in August 2027, from 7 h 57 min on the 1st to 9 h 32 min on the last night.
How cloudy is Tri-Cities in August?: NASA POWER's 2001 to 2020 climatology gives Tri-Cities's 1 degree cell 29% mean cloud in August, against 56% for the whole year. It is an all-hours average, not a forecast.
What is the best night in August 2027 for aurora in Tri-Cities?: By darkness and moon alone, Aug 1, 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 August or September better in Tri-Cities?: By civil night times the clear share, August scores 6.2 hours at Tri-Cities and September 6.3. 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.