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

On dark, clear nights with enough activity. 30 of 30 nights at Tri-Cities have civil darkness, and 2% of past April days reached Kp 7.

How dark is Tri-Cities in April?

Tri-Cities averages 9.2 hours of civil night a night in April 2027, from 10 h 3 min on the 1st to 8 h 26 min on the last night.

How cloudy is Tri-Cities in April?

NASA POWER's 2001 to 2020 climatology gives Tri-Cities's 1 degree cell 61% mean cloud in April, against 56% for the whole year. It is an all-hours average, not a forecast.

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

By darkness and moon alone, Apr 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 April or May better in Tri-Cities?

By civil night times the clear share, April scores 3.6 hours at Tri-Cities and May 3.4. April comes out ahead.

Tri-Cities · April 2027

Northern lights in Tri-Cities in April 2027

Answer

April gives Tri-Cities 9.2 hours of civil night on the 15th, the 8th darkest of its 12 months, under 61% mean cloud. 2% of April days since 1996 reached Kp 7, enough for the oval edge to reach Tri-Cities.

9.2 h

civil night, average night

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

April 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

April cloud at Tri-Cities averages 61% in NASA POWER's 2001 to 2020 record, 5 points cloudier than its yearly mean. July is Tri-Cities's clearest month at 26%. By civil night times clear sky, April scores 3.6 hours at Tri-Cities, 8th of 12. Seattle, 282 km away, averages 75%, cloudier by 14 points.

Civil night at Tri-Cities starts April at 10 h 3 min and reaches 8 h 26 min by April 30, 1.6 hours shorter. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 6.6 hours on the 15th.

April night by night

April opens toward a new moon on Apr 6, with full moon on Apr 20, in America/Los_Angeles dates. Tri-Cities gets 146 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: Apr 1 (4 h), Apr 2 (4 h), Apr 3 (4 h).

1
21% lit
8.9 h
2
14% lit
9.2 h
3
8% lit
9.4 h
4
3% lit
9.7 h
5
1% lit
9.8 h
6
0% lit
9.8 h
New
7
2% lit
8.8 h
8
6% lit
7.5 h
9
13% lit
6.2 h
10
21% lit
5.0 h
11
32% lit
3.9 h
12
43% lit
3.1 h
13
54% lit
2.4 h
14
65% lit
1.9 h
15
76% lit
1.5 h
16
85% lit
1.1 h
17
92% lit
0.7 h
18
97% lit
0.4 h
19
99% lit
0.0 h
20
100% lit
0.0 h
Full
21
98% lit
1.1 h
22
94% lit
2.2 h
23
88% lit
3.3 h
24
81% lit
4.2 h
25
73% lit
4.9 h
26
65% lit
5.5 h
27
55% lit
5.9 h
28
46% lit
6.3 h
29
37% lit
6.5 h
30
27% lit
6.8 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 Aprils

Tri-Cities needs Kp 7 for the average oval edge to sit overhead. 19 of the 900 April 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.

April across United States

Tri-Cities ranks 4th in United States for civil night on April 15, behind Buffalo at 9.5 hours. Coming from March (11.0 hours at Tri-Cities), April loses darkness, and May brings shorter nights (7.7 hours on the 15th).

Civil night on April 15 and April cloud, month-page towns in United States
Town	Civil night	Cloud
Buffalo	9.5 h	69%
Portland, Maine	9.4 h	62%
Minneapolis	9.3 h	61%
Tri-Cities	9.2 h	61%
Duluth	9.2 h	64%
Fargo	9.2 h	61%
Seattle	9.1 h	75%
Juneau	7.9 h	75%
Anchorage	7.4 h	72%
Eagle River	7.4 h	72%
Fairbanks	6.6 h	59%

Darkness and moon, every night

Tri-Cities, April 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
Thu Apr 1	10 h 3 min	7 h 33 min	8 h 52 min	4 h	21%
Fri Apr 2	9 h 59 min	7 h 29 min	9 h 9 min	4 h	14%
Sat Apr 3	9 h 56 min	7 h 25 min	9 h 25 min	4 h	8%
Sun Apr 4	9 h 52 min	7 h 21 min	9 h 40 min	4 h	3%
Mon Apr 5	9 h 49 min	7 h 17 min	9 h 49 min	4 h	1%
Tue Apr 6	9 h 46 min	7 h 13 min	9 h 46 min	4 h	0%
Wed Apr 7	9 h 42 min	7 h 9 min	8 h 51 min	4 h	2%
Thu Apr 8	9 h 39 min	7 h 5 min	7 h 31 min	3 h 44 min	6%
Fri Apr 9	9 h 35 min	7 h	6 h 12 min	2 h 27 min	13%
Sat Apr 10	9 h 32 min	6 h 56 min	4 h 58 min	1 h 14 min	21%
Sun Apr 11	9 h 29 min	6 h 52 min	3 h 55 min	13 min	32%
Mon Apr 12	9 h 25 min	6 h 48 min	3 h 4 min	0 min	43%
Tue Apr 13	9 h 22 min	6 h 43 min	2 h 24 min	0 min	54%
Wed Apr 14	9 h 19 min	6 h 39 min	1 h 53 min	0 min	65%
Thu Apr 15	9 h 15 min	6 h 35 min	1 h 28 min	0 min	76%
Fri Apr 16	9 h 12 min	6 h 30 min	1 h 5 min	0 min	85%
Sat Apr 17	9 h 9 min	6 h 26 min	44 min	0 min	92%
Sun Apr 18	9 h 5 min	6 h 22 min	23 min	0 min	97%
Mon Apr 19	9 h 2 min	6 h 17 min	1 min	0 min	99%
Tue Apr 20	8 h 59 min	6 h 13 min	0 min	0 min	100%
Wed Apr 21	8 h 55 min	6 h 8 min	1 h 3 min	0 min	98%
Thu Apr 22	8 h 52 min	6 h 4 min	2 h 13 min	42 min	94%
Fri Apr 23	8 h 49 min	5 h 59 min	3 h 16 min	1 h 47 min	88%
Sat Apr 24	8 h 45 min	5 h 55 min	4 h 10 min	2 h 42 min	81%
Sun Apr 25	8 h 42 min	5 h 50 min	4 h 53 min	3 h 27 min	73%
Mon Apr 26	8 h 39 min	5 h 46 min	5 h 27 min	4 h	65%
Tue Apr 27	8 h 36 min	5 h 41 min	5 h 54 min	4 h	55%
Wed Apr 28	8 h 32 min	5 h 37 min	6 h 15 min	4 h	46%
Thu Apr 29	8 h 29 min	5 h 32 min	6 h 33 min	4 h	37%
Fri Apr 30	8 h 26 min	5 h 27 min	6 h 49 min	4 h	27%

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 April?: On dark, clear nights with enough activity. 30 of 30 nights at Tri-Cities have civil darkness, and 2% of past April days reached Kp 7.
How dark is Tri-Cities in April?: Tri-Cities averages 9.2 hours of civil night a night in April 2027, from 10 h 3 min on the 1st to 8 h 26 min on the last night.
How cloudy is Tri-Cities in April?: NASA POWER's 2001 to 2020 climatology gives Tri-Cities's 1 degree cell 61% mean cloud in April, against 56% for the whole year. It is an all-hours average, not a forecast.
What is the best night in April 2027 for aurora in Tri-Cities?: By darkness and moon alone, Apr 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 April or May better in Tri-Cities?: By civil night times the clear share, April scores 3.6 hours at Tri-Cities and May 3.4. April 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.