Is Sheffield or Mansfield better for the northern lights?

Sheffield sits closer to the oval, at 55.4 degrees geomagnetic against 55.1. 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, Sheffield or Mansfield?

Sheffield, with 14.9 hours of civil night on December 15 against 14.9 in Mansfield.

What Kp do Sheffield and Mansfield need?

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

When is it too light for aurora in Sheffield and Mansfield?

Sheffield: never, every night has civil darkness. Mansfield: never, every night has civil darkness.

Which is clearer, Sheffield or Mansfield?

Sheffield, with 74% mean cloud in the months with 4 hours or more of civil night against 74% in Mansfield (NASA POWER, 2001 to 2020).

Comparison

Sheffield vs Mansfield for the northern lights

Answer

Sheffield sits 0.3 degrees higher on the IGRF-14 dipole, 55.4 against 55.1. By SWPC's oval-edge rule Sheffield needs about Kp 6 for the average edge to sit overhead and Mansfield Kp 6. On the map Sheffield is also closer to the pole, by 0.2 degrees.

55.4° / 55.1°

dipole latitude

Side by side

Computed figures for both towns
Figure	Sheffield	Mansfield
Dipole latitude	55.4°	55.1°
Kp for the oval edge overhead	Kp 6	Kp 6
Civil night, December 15	14.9 h	14.9 h
Dark-season days	365	365
Nights with no civil darkness	0	0
Dark-month cloud, NASA POWER	74%	74%
Solar midnight, December 15	00:01	00:00

Sheffield sits at 55.4 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. Mansfield sits at 55.1 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 Sheffield has 14.9 hours of civil night and Mansfield 14.9. Across the 15th of each month, Sheffield is darker in 0 months and Mansfield in 3. The widest gap comes in June, when Mansfield has 0.1 more hours.

Hours of civil night on the 15th of each month, 2026
Month	Sheffield	Mansfield	Difference
January	14.4 h	14.4 h	+0.0 h
February	12.8 h	12.8 h	+0.0 h
March	10.9 h	10.9 h	+0.0 h
April	8.6 h	8.6 h	+0.0 h
May	6.4 h	6.5 h	-0.1 h
June	5.1 h	5.2 h	-0.1 h
July	5.8 h	5.8 h	+0.0 h
August	7.8 h	7.8 h	+0.0 h
September	10.0 h	10.1 h	-0.1 h
October	12.1 h	12.1 h	+0.0 h
November	14.0 h	14.0 h	+0.0 h
December	14.9 h	14.9 h	+0.0 h

Difference: Sheffield minus Mansfield. Each figure links to that town's month page.

Season and midnight sun

Sheffield has some civil darkness every night of 2026, and clears Glow's 4-hour dark-season bar every evening. Mansfield 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 33 km apart by great circle. In the dark months both average about 74% cloud in NASA POWER's 2001 to 2020 record. Sheffield's best month by civil night times clear sky is December. Mansfield'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 Sheffield and Mansfield, which carry the live OVATION cell.

Questions

Is Sheffield or Mansfield better for the northern lights?: Sheffield sits closer to the oval, at 55.4 degrees geomagnetic against 55.1. 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, Sheffield or Mansfield?: Sheffield, with 14.9 hours of civil night on December 15 against 14.9 in Mansfield.
What Kp do Sheffield and Mansfield need?: By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Sheffield needs about Kp 6 and Mansfield Kp 6 for the average oval edge to sit overhead.
When is it too light for aurora in Sheffield and Mansfield?: Sheffield: never, every night has civil darkness. Mansfield: never, every night has civil darkness.
Which is clearer, Sheffield or Mansfield?: Sheffield, with 74% mean cloud in the months with 4 hours or more of civil night against 74% in Mansfield (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.