Is Saguenay or Trois-Rivières better for the northern lights?

Saguenay sits closer to the oval, at 57.6 degrees geomagnetic against 55.6. 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, Saguenay or Trois-Rivières?

Saguenay, with 14.3 hours of civil night on December 15 against 14.1 in Trois-Rivières.

What Kp do Saguenay and Trois-Rivières need?

By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Saguenay needs about Kp 5 and Trois-Rivières Kp 6 for the average oval edge to sit overhead.

When is it too light for aurora in Saguenay and Trois-Rivières?

Saguenay: never, every night has civil darkness. Trois-Rivières: never, every night has civil darkness.

Which is clearer, Saguenay or Trois-Rivières?

Trois-Rivières, with 65% mean cloud in the months with 4 hours or more of civil night against 70% in Saguenay (NASA POWER, 2001 to 2020).

Comparison

Saguenay vs Trois-Rivières for the northern lights

Answer

Saguenay sits 2.1 degrees higher on the IGRF-14 dipole, 57.6 against 55.6. By SWPC's oval-edge rule Saguenay needs about Kp 5 for the average edge to sit overhead and Trois-Rivières Kp 6. On the map Saguenay is also closer to the pole, by 2.1 degrees.

57.6° / 55.6°

dipole latitude

Side by side

Computed figures for both towns
Figure	Saguenay	Trois-Rivières
Dipole latitude	57.6°	55.6°
Kp for the oval edge overhead	Kp 5	Kp 6
Civil night, December 15	14.3 h	14.1 h
Dark-season days	365	365
Nights with no civil darkness	0	0
Dark-month cloud, NASA POWER	70%	65%
Solar midnight, December 15	23:39	23:45

Saguenay sits at 57.6 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. Trois-Rivières sits at 55.6 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 6, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less.

Civil night month by month

On December 15 Saguenay has 14.3 hours of civil night and Trois-Rivières 14.1. Across the 15th of each month, Saguenay is darker in 4 months and Trois-Rivières in 6. The widest gap comes in June, when Trois-Rivières has 0.4 more hours.

Hours of civil night on the 15th of each month, 2026
Month	Saguenay	Trois-Rivières	Difference
January	13.9 h	13.8 h	+0.1 h
February	12.6 h	12.5 h	+0.1 h
March	11.0 h	11.0 h	+0.0 h
April	9.1 h	9.2 h	-0.1 h
May	7.4 h	7.7 h	-0.3 h
June	6.4 h	6.8 h	-0.4 h
July	6.9 h	7.2 h	-0.3 h
August	8.4 h	8.7 h	-0.3 h
September	10.3 h	10.4 h	-0.1 h
October	12.0 h	12.0 h	+0.0 h
November	13.6 h	13.4 h	+0.2 h
December	14.3 h	14.1 h	+0.2 h

Difference: Saguenay minus Trois-Rivières. Each figure links to that town's month page.

Season and midnight sun

Saguenay has some civil darkness every night of 2026, and clears Glow's 4-hour dark-season bar every evening. Trois-Rivières 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 256 km apart by great circle. In the dark months Trois-Rivières averages 65% cloud and Saguenay 70%, from NASA POWER's 2001 to 2020 record. Saguenay's best month by civil night times clear sky is January. Trois-Rivières's best month by civil night times clear sky is January. Time zones: America/Toronto and America/Toronto.

For tonight, open the live pages for Saguenay and Trois-Rivières, which carry the live OVATION cell.

Questions

Is Saguenay or Trois-Rivières better for the northern lights?: Saguenay sits closer to the oval, at 57.6 degrees geomagnetic against 55.6. 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, Saguenay or Trois-Rivières?: Saguenay, with 14.3 hours of civil night on December 15 against 14.1 in Trois-Rivières.
What Kp do Saguenay and Trois-Rivières need?: By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Saguenay needs about Kp 5 and Trois-Rivières Kp 6 for the average oval edge to sit overhead.
When is it too light for aurora in Saguenay and Trois-Rivières?: Saguenay: never, every night has civil darkness. Trois-Rivières: never, every night has civil darkness.
Which is clearer, Saguenay or Trois-Rivières?: Trois-Rivières, with 65% mean cloud in the months with 4 hours or more of civil night against 70% in Saguenay (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.