Viljandimaa, Estonia
Northern lights in Viljandi
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/Tallinn
Storm level needed
Viljandi sits at 58.36N 25.59E in Viljandimaa, Estonia. The IGRF-14 centered dipole puts Viljandi at 55.9 degrees geomagnetic latitude, 2.4 degrees farther from the magnetic pole than its map latitude suggests. Viljandi 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.
"aurora is commonly visible at high latitudes (northern Michigan and Maine)"
The nearest other Glow towns are Pärnu (64 km), Tartu (66 km), Valmiera (92 km). Pärnu sits 0.2 degrees higher on the dipole, Kp 5 against 6 here.
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
Every night of 2026 at Viljandi has some civil darkness; the shortest month sample still has 2.8 hours. Glow's dark season, at least 4 hours of civil night between 18:00 and 06:00, runs from July 16 to May 26 across New Year, 315 days in 2026. Viljandi's longest night of the year, Dec 18, has 15 h 44 min of civil night.
Solar midnight at Viljandi, when the sun is lowest, falls at 00:13 on local clocks on December 15 and 01:18 on June 15. That is 13 min after midnight in December and 1 h 18 min after midnight in June, the gap set by daylight saving and the equation of time. So at Viljandi 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 | 15.1 h | 11.8 h | 84% | 2.4 h | |
| Feb | 13.1 h | 10.0 h | 78% | 2.9 h | |
| Mar | 10.8 h | 7.5 h | 68% | 3.5 hbest | |
| Apr | 8.0 h | 3.4 h | 61% | 3.1 h | |
| May | 5.1 h | 0.0 h | 56% | 2.2 h | |
| Jun | 2.8 h | 0.0 h | 63% | 1.0 h | |
| Jul | 4.0 h | 0.0 h | 63% | 1.5 h | |
| Aug | 6.9 h | 0.0 h | 63% | 2.6 h | |
| Sep | 9.7 h | 6.3 h | 68% | 3.1 h | |
| Oct | 12.3 h | 9.2 h | 75% | 3.1 h | |
| Nov | 14.5 h | 11.3 h | 84% | 2.3 h | |
| Dec | 15.7 h | 12.3 h | 86% | 2.2 h |
By the 15th-of-the-month sample, December is the darkest month at Viljandi with 15.7 hours of civil night and June the lightest at 2.8. Across the year Viljandi gets 3,577 hours of civil night. Astronomical night at Viljandi, the sun 18 degrees or more below the horizon, lasts 12.3 hours on December 15.
NASA POWER's 2001 to 2020 all-hours climatology puts mean cloud amount for the 1 degree cell around Viljandi at 71% across the year, from 56% in May to 86% in December. In the months with at least 4 hours of civil night Viljandi averages 71%, against a median of 74% for Glow towns in Estonia.
Multiplying civil night by the clear share of the sky gives March the best score, 3.5 hours, ahead of April at 3.1. Viljandi's equinox months score 3.5 in March and 3.1 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 6 or more, the level that puts the average oval edge over Viljandi, on 3% of days. At Viljandi's level the share runs from 1% in December to 5% in October, 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 6. 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/Tallinn dates. 15 of the 30 nights at Viljandi have at least 2 moon-free dark hours inside 10 PM to 2 AM, and Oct 6 has the most at 4 h. Tonight Viljandi has 11 h 11 min of civil night, 1 h 5 min of it with the moon down.
- 2
58% lit
1.1 h
- 3
47% lit
2.5 h
- 4
35% lit
4.2 h
- 5
25% lit
6.0 h
- 6
16% lit
7.7 h
- 7
9% lit
9.3 h
- 8
4% lit
10.8 h
- 9
1% lit
11.8 h
- 10
0% lit
11.8 h
- 11
2% lit
11.9 h
- 12
5% lit
12.0 h
- 13
10% lit
12.1 h
- 14
17% lit
12.2 h
- 15
25% lit
12.3 h
- 16
33% lit
11.5 h
- 17
43% lit
10.3 h
- 18
52% lit
8.9 h
- 19
62% lit
7.5 h
- 20
71% lit
6.1 h
- 21
79% lit
4.7 h
- 22
87% lit
3.3 h
- 23
93% lit
1.8 h
- 24
98% lit
0.3 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
0.1 h
- 30
72% lit
1.5 h
- 31
61% lit
3.1 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 Estonia
Among the 6 Glow towns in Estonia, Viljandi ranks 5th by dipole latitude against a national median of 56.3 degrees; Tallinn sits highest at 57.1. On December 15 Viljandi gets 15.7 hours of civil night, 4th longest of 6 in Estonia, where the median is 15.8.
Questions
- Can you see the northern lights in Viljandi?
- Viljandi 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. Clear, dark sky over Viljandi still decides it.
- When is it dark enough in Viljandi?
- Every night at Viljandi has civil darkness. Tonight has 11 h 11 min, and December 15 has 15.7 hours.
- What is the best month for aurora in Viljandi?
- March, by civil night at Viljandi times the clear share of the sky from NASA POWER's 2001 to 2020 average.
- How cloudy is Viljandi in the dark months?
- About 71% mean cloud amount over Viljandi 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 Viljandi?
- A 3-hour Kp of 6 or more, the level that puts the average oval edge overhead, occurred on 3% of days from 1996 to 2025 in the GFZ Potsdam record.
Nearby and related
Nearest Glow towns
Viljandi by month
Region and comparisons