Can you see the northern lights in Renton in April?

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

How dark is Renton in April?

Renton averages 9.1 hours of civil night a night in April 2027, from 9 h 59 min on the 1st to 8 h 18 min on the last night.

How cloudy is Renton in April?

NASA POWER's 2001 to 2020 climatology gives Renton's 1 degree cell 75% mean cloud in April, against 68% for the whole year. It is an all-hours average, not a forecast.

What is the best night in April 2027 for aurora in Renton?

By darkness and moon alone, Apr 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Renton. Activity on that date will only be known hours ahead.

Is April or May better in Renton?

By civil night times the clear share, April scores 2.3 hours at Renton and May 2.3. April comes out ahead.

Renton · April 2027

Northern lights in Renton in April 2027

Answer

April gives Renton 9.1 hours of civil night on the 15th, the 8th darkest of its 12 months, under 75% mean cloud. 2% of April days since 1996 reached Kp 7, enough for the oval edge to reach Renton.

9.1 h

civil night, average night

SunCalc for 47.48, -122.22; NASA POWER; GFZ Kp

April against the rest of the year

2.8

3.3

2.3

2.1

3.7

4.4

4.8

3.8

3.1

3.0

April cloud at Renton averages 75% in NASA POWER's 2001 to 2020 record, 7 points cloudier than its yearly mean. July is Renton's clearest month at 47%. By civil night times clear sky, April scores 2.3 hours at Renton, 10th of 12. Seattle, 16 km away, averages the same 75%.

Civil night at Renton starts April at 9 h 59 min and reaches 8 h 18 min by April 30, 1.7 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 6.4 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. Renton gets 144 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
9.6 h
5
1% lit
9.8 h
6
0% lit
9.7 h
New
7
2% lit
8.7 h
8
6% lit
7.4 h
9
13% lit
6.0 h
10
21% lit
4.8 h
11
32% lit
3.8 h
12
43% lit
2.9 h
13
54% lit
2.3 h
14
65% lit
1.8 h
15
76% lit
1.4 h
16
85% lit
1.0 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
2.3 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

Renton 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%. Renton sits at 52.9 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

Renton ranks 6th in United States for civil night on April 15, behind Buffalo at 9.5 hours. Coming from March (11.0 hours at Renton), April loses darkness, and May brings shorter nights (7.5 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%
Duluth	9.2 h	64%
Fargo	9.2 h	61%
Renton	9.1 h	75%
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

Renton, 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	9 h 59 min	7 h 25 min	8 h 53 min	4 h	21%
Fri Apr 2	9 h 55 min	7 h 21 min	9 h 9 min	4 h	14%
Sat Apr 3	9 h 52 min	7 h 17 min	9 h 24 min	4 h	8%
Sun Apr 4	9 h 48 min	7 h 12 min	9 h 38 min	4 h	3%
Mon Apr 5	9 h 45 min	7 h 8 min	9 h 45 min	4 h	1%
Tue Apr 6	9 h 41 min	7 h 4 min	9 h 41 min	4 h	0%
Wed Apr 7	9 h 38 min	6 h 59 min	8 h 44 min	4 h	2%
Thu Apr 8	9 h 34 min	6 h 55 min	7 h 23 min	3 h 26 min	6%
Fri Apr 9	9 h 30 min	6 h 50 min	6 h 3 min	2 h 8 min	13%
Sat Apr 10	9 h 27 min	6 h 46 min	4 h 48 min	55 min	21%
Sun Apr 11	9 h 23 min	6 h 41 min	3 h 45 min	0 min	32%
Mon Apr 12	9 h 20 min	6 h 37 min	2 h 55 min	0 min	43%
Tue Apr 13	9 h 16 min	6 h 32 min	2 h 17 min	0 min	54%
Wed Apr 14	9 h 13 min	6 h 28 min	1 h 47 min	0 min	65%
Thu Apr 15	9 h 9 min	6 h 23 min	1 h 23 min	0 min	76%
Fri Apr 16	9 h 6 min	6 h 18 min	1 h 1 min	0 min	85%
Sat Apr 17	9 h 2 min	6 h 14 min	41 min	0 min	92%
Sun Apr 18	8 h 59 min	6 h 9 min	22 min	0 min	97%
Mon Apr 19	8 h 55 min	6 h 4 min	0 min	0 min	99%
Tue Apr 20	8 h 52 min	6 h	0 min	0 min	100%
Wed Apr 21	8 h 48 min	5 h 55 min	1 h 6 min	0 min	98%
Thu Apr 22	8 h 45 min	5 h 50 min	2 h 16 min	1 h 1 min	94%
Fri Apr 23	8 h 41 min	5 h 45 min	3 h 20 min	2 h 6 min	88%
Sat Apr 24	8 h 38 min	5 h 40 min	4 h 14 min	3 h 1 min	81%
Sun Apr 25	8 h 35 min	5 h 35 min	4 h 56 min	3 h 46 min	73%
Mon Apr 26	8 h 31 min	5 h 31 min	5 h 29 min	4 h	65%
Tue Apr 27	8 h 28 min	5 h 26 min	5 h 55 min	4 h	55%
Wed Apr 28	8 h 24 min	5 h 21 min	6 h 15 min	4 h	46%
Thu Apr 29	8 h 21 min	5 h 16 min	6 h 32 min	4 h	37%
Fri Apr 30	8 h 18 min	5 h 11 min	6 h 47 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 Renton in April?: On dark, clear nights with enough activity. 30 of 30 nights at Renton have civil darkness, and 2% of past April days reached Kp 7.
How dark is Renton in April?: Renton averages 9.1 hours of civil night a night in April 2027, from 9 h 59 min on the 1st to 8 h 18 min on the last night.
How cloudy is Renton in April?: NASA POWER's 2001 to 2020 climatology gives Renton's 1 degree cell 75% mean cloud in April, against 68% for the whole year. It is an all-hours average, not a forecast.
What is the best night in April 2027 for aurora in Renton?: By darkness and moon alone, Apr 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Renton. Activity on that date will only be known hours ahead.
Is April or May better in Renton?: By civil night times the clear share, April scores 2.3 hours at Renton and May 2.3. 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.