Can you see the northern lights in Hillsboro in December?

On dark, clear nights with enough activity. 31 of 31 nights at Hillsboro have civil darkness, and 0% of past December days reached Kp 8.

How dark is Hillsboro in December?

Hillsboro averages 14.0 hours of civil night a night in December 2026, from 13 h 50 min on the 1st to 14 h on the last night.

How cloudy is Hillsboro in December?

NASA POWER's 2001 to 2020 climatology gives Hillsboro's 1 degree cell 81% mean cloud in December, against 65% for the whole year. It is an all-hours average, not a forecast.

What is the best night in December 2026 for aurora in Hillsboro?

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

Is December or January better in Hillsboro?

By civil night times the clear share, December scores 2.7 hours at Hillsboro and January 2.9. January comes out ahead.

Hillsboro · December 2026

Northern lights in Hillsboro in December 2026

Answer

December gives Hillsboro 14.0 hours of civil night on the 15th, the darkest month of its year, under 81% mean cloud. 0% of December days since 1996 reached Kp 8, enough for the oval edge to reach Hillsboro.

14.0 h

civil night, average night

SunCalc for 45.52, -122.99; NASA POWER; GFZ Kp

December against the rest of the year

2.9

3.1

2.4

2.3

2.5

2.6

4.5

5.2

5.5

4.4

3.1

2.7

December cloud at Hillsboro averages 81% in NASA POWER's 2001 to 2020 record, 16 points cloudier than its yearly mean. July is Hillsboro's clearest month at 39%. By civil night times clear sky, December scores 2.7 hours at Hillsboro, 8th of 12. Seattle, 237 km away, averages 79%, clearer by 2 points.

Civil night at Hillsboro starts December at 13 h 50 min and reaches 14 h by December 31 as the nights lengthen by 0.2 hours. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 11.6 hours on the 15th.

December night by night

December opens toward a new moon on Dec 8, with full moon on Dec 23, in America/Los_Angeles dates. Hillsboro gets 234 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: Dec 2 (4 h), Dec 3 (4 h), Dec 4 (4 h).

1
39% lit
8.0 h
2
29% lit
9.1 h
3
20% lit
10.3 h
4
13% lit
11.4 h
5
7% lit
12.6 h
6
3% lit
13.7 h
7
1% lit
13.9 h
8
0% lit
14.0 h
New
9
2% lit
14.0 h
10
5% lit
13.4 h
11
9% lit
12.4 h
12
16% lit
11.3 h
13
23% lit
10.2 h
14
32% lit
9.1 h
15
41% lit
8.0 h
16
51% lit
6.9 h
17
61% lit
5.8 h
18
71% lit
4.5 h
19
81% lit
3.3 h
20
89% lit
1.9 h
21
95% lit
0.6 h
22
99% lit
0.0 h
23
100% lit
0.0 h
Full
24
97% lit
0.2 h
25
92% lit
1.6 h
26
85% lit
3.0 h
27
76% lit
4.4 h
28
66% lit
5.6 h
29
55% lit
6.8 h
30
45% lit
8.0 h
31
35% lit
9.2 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 Decembers

Hillsboro needs Kp 8 for the average oval edge to sit overhead. 1 of the 930 December days from 1996 to 2025 (0%) reached it in the GFZ Potsdam record, one of the three quietest months for that level; storm days with Kp 5 or more made up 5%. Hillsboro sits at 50.9 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 8.

December across United States

Hillsboro ranks 8th in United States for civil night on December 15, behind Fairbanks at 17.2 hours. Coming from November (13.4 hours at Hillsboro), December adds darkness, and January brings shorter nights (13.7 hours on the 15th). The December solstice falls on December 21, 12:49 Hillsboro time.

Civil night on December 15 and December cloud, month-page towns in United States
Town	Civil night	Cloud
Fairbanks	17.2 h	59%
Anchorage	16.3 h	72%
Eagle River	16.3 h	72%
Juneau	15.7 h	80%
Seattle	14.3 h	79%
Duluth	14.2 h	71%
Fargo	14.2 h	68%
Hillsboro	14.0 h	81%
Minneapolis	14.0 h	69%
Portland, Maine	13.9 h	66%
Buffalo	13.8 h	85%

Darkness and moon, every night

Hillsboro, December 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
Tue Dec 1	13 h 50 min	11 h 25 min	7 h 57 min	3 h 3 min	39%
Wed Dec 2	13 h 51 min	11 h 26 min	9 h 7 min	4 h	29%
Thu Dec 3	13 h 53 min	11 h 27 min	10 h 17 min	4 h	20%
Fri Dec 4	13 h 54 min	11 h 28 min	11 h 27 min	4 h	13%
Sat Dec 5	13 h 55 min	11 h 29 min	12 h 36 min	4 h	7%
Sun Dec 6	13 h 56 min	11 h 30 min	13 h 43 min	4 h	3%
Mon Dec 7	13 h 57 min	11 h 31 min	13 h 57 min	4 h	1%
Tue Dec 8	13 h 58 min	11 h 32 min	13 h 58 min	4 h	0%
Wed Dec 9	13 h 59 min	11 h 32 min	13 h 59 min	4 h	2%
Thu Dec 10	14 h	11 h 33 min	13 h 27 min	4 h	5%
Fri Dec 11	14 h	11 h 34 min	12 h 24 min	4 h	9%
Sat Dec 12	14 h 1 min	11 h 34 min	11 h 19 min	4 h	16%
Sun Dec 13	14 h 2 min	11 h 35 min	10 h 13 min	4 h	23%
Mon Dec 14	14 h 2 min	11 h 35 min	9 h 8 min	4 h	32%
Tue Dec 15	14 h 2 min	11 h 36 min	8 h 2 min	2 h 54 min	41%
Wed Dec 16	14 h 3 min	11 h 36 min	6 h 56 min	1 h 46 min	51%
Thu Dec 17	14 h 3 min	11 h 36 min	5 h 46 min	36 min	61%
Fri Dec 18	14 h 3 min	11 h 36 min	4 h 33 min	0 min	71%
Sat Dec 19	14 h 4 min	11 h 36 min	3 h 16 min	0 min	81%
Sun Dec 20	14 h 4 min	11 h 37 min	1 h 55 min	0 min	89%
Mon Dec 21	14 h 4 min	11 h 37 min	35 min	0 min	95%
Tue Dec 22	14 h 4 min	11 h 36 min	0 min	0 min	99%
Wed Dec 23	14 h 3 min	11 h 36 min	0 min	0 min	100%
Thu Dec 24	14 h 3 min	11 h 36 min	14 min	0 min	97%
Fri Dec 25	14 h 3 min	11 h 36 min	1 h 39 min	0 min	92%
Sat Dec 26	14 h 3 min	11 h 36 min	3 h 3 min	0 min	85%
Sun Dec 27	14 h 2 min	11 h 35 min	4 h 23 min	0 min	76%
Mon Dec 28	14 h 2 min	11 h 35 min	5 h 38 min	51 min	66%
Tue Dec 29	14 h 1 min	11 h 34 min	6 h 50 min	2 h 3 min	55%
Wed Dec 30	14 h	11 h 34 min	8 h	3 h 14 min	45%
Thu Dec 31	14 h	11 h 33 min	9 h 9 min	4 h	35%

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

Questions

Can you see the northern lights in Hillsboro in December?: On dark, clear nights with enough activity. 31 of 31 nights at Hillsboro have civil darkness, and 0% of past December days reached Kp 8.
How dark is Hillsboro in December?: Hillsboro averages 14.0 hours of civil night a night in December 2026, from 13 h 50 min on the 1st to 14 h on the last night.
How cloudy is Hillsboro in December?: NASA POWER's 2001 to 2020 climatology gives Hillsboro's 1 degree cell 81% mean cloud in December, against 65% for the whole year. It is an all-hours average, not a forecast.
What is the best night in December 2026 for aurora in Hillsboro?: By darkness and moon alone, Dec 2, with 4 h of moon-free darkness inside 10 PM to 2 AM at Hillsboro. Activity on that date will only be known hours ahead.
Is December or January better in Hillsboro?: By civil night times the clear share, December scores 2.7 hours at Hillsboro and January 2.9. January 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.