Is Seattle or Kamloops better for the northern lights?

Kamloops sits closer to the oval, at 56.3 degrees geomagnetic against 53.0. Darkness, cloud and your dates decide the rest; the tables on this page show both towns month by month.

Which has longer nights in December, Seattle or Kamloops?

Kamloops, with 14.6 hours of civil night on December 15 against 14.3 in Seattle.

What Kp do Seattle and Kamloops need?

By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Seattle needs about Kp 7 and Kamloops Kp 5 for the average oval edge to sit overhead.

When is it too light for aurora in Seattle and Kamloops?

Seattle: never, every night has civil darkness. Kamloops: never, every night has civil darkness.

Which is clearer, Seattle or Kamloops?

Kamloops, with 67% mean cloud in the months with 4 hours or more of civil night against 68% in Seattle (NASA POWER, 2001 to 2020).

Comparison

Seattle vs Kamloops for the northern lights

Answer

Kamloops sits 3.3 degrees higher on the IGRF-14 dipole, 56.3 against 53.0. By SWPC's oval-edge rule Kamloops needs about Kp 5 for the average edge to sit overhead and Seattle Kp 7. On the map Kamloops is also closer to the pole, by 3.1 degrees.

53.0° / 56.3°

dipole latitude

Side by side

Computed figures for both towns
Figure	Seattle	Kamloops
Dipole latitude	53.0°	56.3°
Kp for the oval edge overhead	Kp 7	Kp 5
Civil night, December 15	14.3 h	14.6 h
Dark-season days	365	365
Nights with no civil darkness	0	0
Dark-month cloud, NASA POWER	68%	67%
Solar midnight, December 15	00:05	00:57

Seattle sits at 53.0 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. Kamloops sits at 56.3 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 5, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less.

Civil night month by month

On December 15 Seattle has 14.3 hours of civil night and Kamloops 14.6. Across the 15th of each month, Seattle is darker in 7 months and Kamloops in 5. The widest gap comes in June, when Seattle has 0.6 more hours.

Hours of civil night on the 15th of each month, 2026
Month	Seattle	Kamloops	Difference
January	13.9 h	14.1 h	-0.2 h
February	12.5 h	12.6 h	-0.1 h
March	11.0 h	10.9 h	+0.1 h
April	9.1 h	8.9 h	+0.2 h
May	7.5 h	7.0 h	+0.5 h
June	6.5 h	5.9 h	+0.6 h
July	7.0 h	6.4 h	+0.6 h
August	8.5 h	8.2 h	+0.3 h
September	10.3 h	10.2 h	+0.1 h
October	12.0 h	12.1 h	-0.1 h
November	13.5 h	13.8 h	-0.3 h
December	14.3 h	14.6 h	-0.3 h

Difference: Seattle minus Kamloops. Each figure links to that town's month page.

Season and midnight sun

Seattle has some civil darkness every night of 2026, and clears Glow's 4-hour dark-season bar every evening. Kamloops has some civil darkness every night of 2026, and clears Glow's 4-hour dark-season bar every evening.

Distance, cloud and time zones

The two towns are 370 km apart by great circle. In the dark months both average about 68% cloud in NASA POWER's 2001 to 2020 record. Seattle's best month by civil night times clear sky is September. Kamloops's best month by civil night times clear sky is September. Time zones: America/Los_Angeles and America/Vancouver.

For tonight, open the live pages for Seattle and Kamloops, which carry the live OVATION cell.

Questions

Is Seattle or Kamloops better for the northern lights?: Kamloops sits closer to the oval, at 56.3 degrees geomagnetic against 53.0. Darkness, cloud and your dates decide the rest; the tables on this page show both towns month by month.
Which has longer nights in December, Seattle or Kamloops?: Kamloops, with 14.6 hours of civil night on December 15 against 14.3 in Seattle.
What Kp do Seattle and Kamloops need?: By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Seattle needs about Kp 7 and Kamloops Kp 5 for the average oval edge to sit overhead.
When is it too light for aurora in Seattle and Kamloops?: Seattle: never, every night has civil darkness. Kamloops: never, every night has civil darkness.
Which is clearer, Seattle or Kamloops?: Kamloops, with 67% mean cloud in the months with 4 hours or more of civil night against 68% in Seattle (NASA POWER, 2001 to 2020).

Sources and verification

IGRF-14 coefficients, NOAA NCEIhttps://www.ngdc.noaa.gov/IAGA/vmod/coeffs/igrf14coeffs.txt
SunCalchttps://github.com/mourner/suncalc
GeoNameshttps://www.geonames.org/export/
NASA POWER climatologyhttps://power.larc.nasa.gov/docs/services/api/temporal/climatology/
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.