Uusimaa, Finland
Northern lights in Mäntsälä
Answer
Tonight
Waiting on darkness
It is not civil-dark yet. The next dusk is listed below.
Observed 11:49 UTC, forecast 13:20 UTC, 91 min lead
Clock times in Europe/Helsinki
Storm level needed
Mäntsälä sits at 60.63N 25.32E in Uusimaa, Finland. The IGRF-14 centered dipole puts Mäntsälä at 58.1 degrees geomagnetic latitude, 2.5 degrees farther from the magnetic pole than its map latitude suggests. Mäntsälä sits at 58.1 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 4, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less.
"aurora is commonly visible at high latitudes (northern Michigan and Maine)"
The nearest other Glow towns are Järvenpää (22 km), Hyvinge (25 km), Sibbo (29 km). Järvenpää sits 0.1 degrees lower on the dipole and needs the same Kp.
Approximate: SWPC calls its Kp to latitude rule an average, and a centered dipole can differ by a degree from fuller field models. How the storm level is matched
The year in darkness
From June 8 to July 3 the sun never reaches -6 degrees, so 26 nights in 2026 have no civil darkness at all. SWPC puts it plainly: "It must also be dark so during the summer months at auroral latitudes, the midnight sun prevents auroral observations." Glow's dark season, at least 4 hours of civil night between 18:00 and 06:00, runs from July 26 to May 16 across New Year, 295 days in 2026. Mäntsälä's longest night of the year, Dec 19, has 16 h 11 min of civil night.
Solar midnight at Mäntsälä, when the sun is lowest, falls at 00:14 on local clocks on December 15 and 01:19 on June 15. That is 14 min after midnight in December and 1 h 19 min after midnight in June, the gap set by daylight saving and the equation of time. So at Mäntsälä the darkest hour sits near the middle of SWPC's 10 PM to 2 AM window in winter.
Month by month
| Month | Night | Civil | Cloud | Clear dark | |
|---|---|---|---|---|---|
| Jan | 15.4 h | 11.9 h | 82% | 2.8 h | |
| Feb | 13.2 h | 9.9 h | 79% | 2.8 h | |
| Mar | 10.7 h | 7.2 h | 69% | 3.3 hbest | |
| Apr | 7.6 h | 1.9 h | 67% | 2.5 h | |
| May | 4.1 h | 0.0 h | 62% | 1.6 h | |
| Jun | 0.0 h | 0.0 h | 66% | 0.0 h | |
| Jul | 2.6 h | 0.0 h | 64% | 0.9 h | |
| Aug | 6.3 h | 0.0 h | 63% | 2.4 h | |
| Sep | 9.6 h | 5.7 h | 67% | 3.2 h | |
| Oct | 12.3 h | 9.0 h | 78% | 2.7 h | |
| Nov | 14.8 h | 11.4 h | 85% | 2.2 h | |
| Dec | 16.1 h | 12.5 h | 85% | 2.4 h |
By the 15th-of-the-month sample, December is the darkest month at Mäntsälä with 16.1 hours of civil night and June the lightest at 0.0. Across the year Mäntsälä gets 3,420 hours of civil night. Astronomical night at Mäntsälä, the sun 18 degrees or more below the horizon, lasts 12.5 hours on December 15.
NASA POWER's 2001 to 2020 all-hours climatology puts mean cloud amount for the 1 degree cell around Mäntsälä at 72% across the year, from 62% in May to 85% in November. In the months with at least 4 hours of civil night Mäntsälä averages 74%, against a median of 76% for Glow towns in Finland.
Multiplying civil night by the clear share of the sky gives March the best score, 3.3 hours, ahead of September at 3.2. Mäntsälä's equinox months score 3.3 in March and 3.2 in September, the weeks SWPC links with larger storms.
Kp history
From 1996 to 2025, the GFZ Potsdam record shows a 3-hour Kp of 4 or more, the level that puts the average oval edge over Mäntsälä, on 24% of days. At Mäntsälä's level the share runs from 19% in December to 31% in September, while storm days with Kp 5 or more made up 10%.
Share of UTC days in each calendar month whose highest 3-hour Kp reached Kp 4. Kp history by year
Moon, next 30 nights
Over the 30 nights from Oct 2, the new moon falls on Oct 10 and the full moon on Oct 26, in Europe/Helsinki dates. 15 of the 30 nights at Mäntsälä have at least 2 moon-free dark hours inside 10 PM to 2 AM, and Oct 6 has the most at 4 h. Tonight Mäntsälä has 11 h 9 min of civil night, 22 min of it with the moon down.
- 2
58% lit
0.4 h
- 3
47% lit
2.0 h
- 4
35% lit
3.9 h
- 5
25% lit
5.7 h
- 6
16% lit
7.5 h
- 7
9% lit
9.2 h
- 8
4% lit
10.8 h
- 9
1% lit
11.8 h
- 10
0% lit
11.9 h
- 11
2% lit
12.0 h
- 12
5% lit
12.1 h
- 13
10% lit
12.1 h
- 14
17% lit
12.2 h
- 15
25% lit
12.3 h
- 16
33% lit
12.3 h
- 17
43% lit
10.9 h
- 18
52% lit
9.4 h
- 19
62% lit
7.8 h
- 20
71% lit
6.3 h
- 21
79% lit
4.8 h
- 22
87% lit
3.4 h
- 23
93% lit
1.8 h
- 24
98% lit
0.2 h
- 25
100% lit
0.0 h
- 26
99% lit
0.0 h
- 27
96% lit
0.0 h
- 28
90% lit
0.0 h
- 29
81% lit
0.0 h
- 30
72% lit
1.0 h
- 31
61% lit
2.8 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.
Within Finland
Among the 13 Glow towns in Uusimaa, Mäntsälä ranks 2nd by dipole latitude against a regional median of 57.9 degrees; Hyvinge sits highest at 58.2. Among the 65 Glow towns in Finland, Mäntsälä ranks 50th by dipole latitude against a national median of 59.0 degrees; Rovaniemi sits highest at 63.6. On December 15 Mäntsälä gets 16.1 hours of civil night, 47th longest of 65 in Finland, where the median is 16.3.
Questions
- Can you see the northern lights in Mäntsälä?
- Mäntsälä sits at 58.1 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 4, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less. Clear, dark sky over Mäntsälä still decides it.
- When is it dark enough in Mäntsälä?
- Civil night, the sun at -6 degrees or lower, is missing from Jun 8 to Jul 3. Tonight has 11 h 9 min of it.
- What is the best month for aurora in Mäntsälä?
- March, by civil night at Mäntsälä times the clear share of the sky from NASA POWER's 2001 to 2020 average.
- How cloudy is Mäntsälä in the dark months?
- About 74% mean cloud amount over Mäntsälä in the months with at least 4 hours of civil night, from NASA POWER's 2001 to 2020 all-hours climatology.
- How often is activity high enough for Mäntsälä?
- A 3-hour Kp of 4 or more, the level that puts the average oval edge overhead, occurred on 24% of days from 1996 to 2025 in the GFZ Potsdam record.
Nearby and related
Nearest Glow towns
Mäntsälä by month
Region and comparisons