Aurora Borealis in Porvoo
Finland · 60.39°, 25.67° · geomagnetic 57.8° · needs Kp 7
Tonight in Porvoo
38%
Peak chance of a visible display tonight, from the same model the Revon app runs. Porvoo needs Kp 7 to see anything at all, and tonight the forecast peaks at Kp 5.7. Short of the threshold, which is what most nights look like here.
Updated 2026-08-02 20:20 UTC
The next 30 nights in Porvoo
Every night to come, scored the same way as tonight. The best of the open week is Sunday 2 Aug at 38%. Not one of the seven reaches the Kp 7 that Porvoo needs, which is normal rather than unlucky — it averages 2.3 viable nights a year. The 23 nights past the seven-day window move with the 27-day solar rotation and are updated daily in the app.
Nights 8–30 unlock in the Revon app
Revon aurora model over the NOAA Kp forecast and 27-day outlook
How often the aurora borealis reaches Porvoo
2.3 nights a year, averaged across 10.0 years of records
| Storm level | Nights / year |
|---|---|
| Kp 4 | 83.4 |
| Kp 5 | 28.7 |
| Kp 6 | 9.3 |
| Kp 7 | 3.2 |
| Kp 8 | 1.2 |
NOAA planetary Kp, 2016-04-02 to 2026-03-30
Wait for an alert; do not book a week
At Kp 7, Porvoo needs a severe geomagnetic storm before anything shows above the northern horizon. Storms that size arrive a handful of times per solar cycle and announce themselves a day or two ahead. Watching for one beats picking dates and hoping.
Hours of true darkness, month by month
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 12.1 | 10.2 | 7.6 | 2.8 | 0.0 | 0.0 | 0.0 | 0.0 | 6.2 | 9.4 | 11.6 | 12.6 |
Solar declination and hour angle at −18°
Nothing to see from May to August
Through those months the sun never falls more than 18° below the Porvoo horizon, so the sky never darkens fully. Plan around the darker half of the year.
Getting clear of the light
The sky over Porvoo reads Bortle 5. Getting clear of the built-up area makes a visible difference on a marginal night.
- 13 km north-north-east → Bortle 5
- 44 km south → Bortle 4
Falchi 2016 World Atlas (DOI: 10.5880/GFZ.1.4.2016.001)
The months that actually deliver
Counting only nights that were both stormy enough and dark enough, September, November and March came out ahead in Porvoo. That is storm season and darkness overlapping — the equinoxes tend to be geomagnetically active, and the nights are already long by then.
Darkest nights of the coming year
A bright moon washes out a weak display as effectively as street lighting. These new moons fall inside the Porvoo viewing season.
- 11 Sep 2026
- 11 Oct 2026
- 09 Nov 2026
- 09 Dec 2026
- 07 Jan 2027
- 06 Feb 2027
- 08 Mar 2027
Where it is close to a certainty
If you would rather plan a trip than wait for a storm, the nearest place with genuinely frequent aurora is Rovaniemi, 679 km north in Finland.
| Porvoo | Rovaniemi | |
|---|---|---|
| Kp needed | 7 | 3 |
| Nights per year | 2.3 | 171.4 |
| Geomagnetic latitude | 57.8° | 63.6° |
Confirmed reports from this area
41 verified sightings were logged within 300 km of Porvoo between 2015-01-01 and 2016-12-31. Rare is not the same as impossible.
Aurorasaurus verified positive reports
Where the horizon opens up near Porvoo
The display sits low on the northern horizon, so what beats a better forecast is open ground facing that way. Height gets you above the town glow; water gives you an unbroken skyline. These are within a short drive of Porvoo.
- Jerusalemberget — hill3.1 km north-north-west
- Flaggberget — hill3.4 km east-north-east
- Lillträsket — lake3.4 km east-north-east
- Papinjärvi — lake4.4 km north-north-east
- Holmudden — headland4.8 km east
- Rinäsudden — headland5.2 km east-north-east
Places from GeoNames (CC BY 4.0)
The last nights it was visible here
Nights in the last decade when the storm was strong enough for Porvoo and the sky was dark enough to show it.
| Date | Peak |
|---|---|
| 2026-03-20 | Kp 7.0 |
| 2026-01-20 | Kp 7.67 |
| 2026-01-19 | Kp 8.67 |
| 2025-11-12 | Kp 7.33 |
| 2025-11-11 | Kp 8.67 |
NOAA planetary Kp
Know when it is worth going outside
Revon watches the Porvoo forecast and pushes an alert when the odds for tonight clear your threshold — no checking, no guessing.
Common questions about the aurora borealis in Porvoo
Can you see the aurora borealis from Porvoo?
Yes. On the last 10.0 years of NOAA Kp records, Porvoo had about 2.3 nights a year when the storm was strong enough and the sky dark enough at the same time.
What Kp index do you need to see the aurora borealis in Porvoo?
Kp 7. Porvoo sits at geomagnetic latitude 57.8°, and the auroral oval only reaches that far from the pole once activity hits Kp 7. Storms that size occur about 3.2 nights a year.
When is the best time of year to see the aurora borealis in Porvoo?
September, November and March. Those months scored highest once both conditions are counted together: geomagnetic activity and enough hours of real darkness. From May to August the sky over Porvoo never gets fully dark, so nothing is visible however strong the storm.
Where can you escape the light pollution near Porvoo?
The centre of Porvoo reads Bortle 5. The nearest sky at Bortle 4 is about 44 km south. On a marginal night that drive matters more than the forecast does.
Where is the nearest place to Porvoo with reliable aurora borealis?
Rovaniemi, Finland — 679 km north. It needs only Kp 3 and averages 171.4 viable nights a year against 2.3 in Porvoo.
Nearby towns
Forecasts for places within reach of Porvoo.