Is Belfast or Preston better for the northern lights?

Belfast sits closer to the oval, at 57.3 degrees geomagnetic against 55.9. 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, Belfast or Preston?

Belfast, with 15.1 hours of civil night on December 15 against 15.0 in Preston.

What Kp do Belfast and Preston need?

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

When is it too light for aurora in Belfast and Preston?

Belfast: never, every night has civil darkness. Preston: never, every night has civil darkness.

Which is clearer, Belfast or Preston?

Belfast, with 77% mean cloud in the months with 4 hours or more of civil night against 77% in Preston (NASA POWER, 2001 to 2020).

Comparison

Belfast vs Preston for the northern lights

Answer

Belfast sits 1.3 degrees higher on the IGRF-14 dipole, 57.3 against 55.9. By SWPC's oval-edge rule Belfast needs about Kp 5 for the average edge to sit overhead and Preston Kp 6. On the map Belfast is also closer to the pole, by 0.8 degrees.

57.3° / 55.9°

dipole latitude

Side by side

Computed figures for both towns
Figure	Belfast	Preston
Dipole latitude	57.3°	55.9°
Kp for the oval edge overhead	Kp 5	Kp 6
Civil night, December 15	15.1 h	15.0 h
Dark-season days	365	365
Nights with no civil darkness	0	0
Dark-month cloud, NASA POWER	77%	77%
Solar midnight, December 15	00:19	00:06

Belfast sits at 57.3 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. Preston sits at 55.9 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 Belfast has 15.1 hours of civil night and Preston 15.0. Across the 15th of each month, Belfast is darker in 4 months and Preston in 5. The widest gap comes in June, when Preston has 0.3 more hours.

Hours of civil night on the 15th of each month, 2026
Month	Belfast	Preston	Difference
January	14.6 h	14.5 h	+0.1 h
February	12.8 h	12.8 h	+0.0 h
March	10.9 h	10.9 h	+0.0 h
April	8.5 h	8.6 h	-0.1 h
May	6.2 h	6.4 h	-0.2 h
June	4.7 h	5.0 h	-0.3 h
July	5.4 h	5.6 h	-0.2 h
August	7.6 h	7.7 h	-0.1 h
September	10.0 h	10.0 h	+0.0 h
October	12.2 h	12.1 h	+0.1 h
November	14.1 h	14.0 h	+0.1 h
December	15.1 h	15.0 h	+0.1 h

Difference: Belfast minus Preston. Each figure links to that town's month page.

Season and midnight sun

Belfast has some civil darkness every night of 2026, and clears Glow's 4-hour dark-season bar every evening. Preston 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 229 km apart by great circle. In the dark months both average about 77% cloud in NASA POWER's 2001 to 2020 record. Belfast's best month by civil night times clear sky is December. Preston's best month by civil night times clear sky is December. Time zones: Europe/London and Europe/London.

For tonight, open the live pages for Belfast and Preston, which carry the live OVATION cell.

Questions

Is Belfast or Preston better for the northern lights?: Belfast sits closer to the oval, at 57.3 degrees geomagnetic against 55.9. 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, Belfast or Preston?: Belfast, with 15.1 hours of civil night on December 15 against 15.0 in Preston.
What Kp do Belfast and Preston need?: By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Belfast needs about Kp 5 and Preston Kp 6 for the average oval edge to sit overhead.
When is it too light for aurora in Belfast and Preston?: Belfast: never, every night has civil darkness. Preston: never, every night has civil darkness.
Which is clearer, Belfast or Preston?: Belfast, with 77% mean cloud in the months with 4 hours or more of civil night against 77% in Preston (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.