Aurora Borealis in Porsgrunn

Norway · 59.14°, 9.66° · geomagnetic 59.1° · needs Kp 5

Tonight in Porsgrunn

39%

Peak chance of a visible display tonight, from the same model the Revon app runs. Porsgrunn needs Kp 5, and tonight the forecast peaks at Kp 5.7. That is on the threshold rather than over it, so cloud and moonlight will decide the night.

Tonight Sun 02 Aug
39%
18
20
22
00
02
04
06
Tomorrow Mon 3 Aug
7%
Hour-by-hour for this night is in the app
Tuesday Tue 4 Aug
2%
Hour-by-hour for this night is in the app

Unlock every hour in the app

Updated 2026-08-02 20:20 UTC

The next 30 nights in Porsgrunn

Every night to come, scored the same way as tonight. The best of the open week is Sunday 2 Aug at 39%. One of the seven reaches the Kp 5 that Porsgrunn needs: Sunday 2 Aug, at Kp 5.7. The 23 nights past the seven-day window move with the 27-day solar rotation and are updated daily in the app.

Moderate aurora activity tonight around 4 AM. Similar conditions expected on August 19th.

Sun 2
39%
Kp 5.7
Mon 3
7%
Kp 3.3
Tue 4
2%
Kp 1.9
Wed 5
20%
Kp 3.0
Thu 6
5%
Kp 3.0
Fri 7
4%
Kp 2.0
Sat 8
2%
Kp 2.0

Nights 8–30 unlock in the Revon app

See all 30 nights for Porsgrunn

Revon aurora model over the NOAA Kp forecast and 27-day outlook

How often the aurora borealis reaches Porsgrunn

21.6 nights a year, averaged across 10.0 years of records

Storm levelNights / year
Kp 483.4
Kp 528.7
Kp 69.3
Kp 73.2
Kp 81.2

NOAA planetary Kp, 2016-04-02 to 2026-03-30

Worth watching through the dark half of the year

Kp 5 is a moderate storm — not an everyday event, but common enough that a patient observer in Porsgrunn sees the aurora borealis most winters.

Hours of true darkness, month by month

JanFebMarAprMayJunJulAugSepOctNovDec
12.010.27.83.60.00.00.00.06.59.511.612.5

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 Porsgrunn horizon, so the sky never darkens fully. Plan around the darker half of the year.

Getting clear of the light

The sky over Porsgrunn reads Bortle 5. Getting clear of the built-up area makes a visible difference on a marginal night.

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, March and October came out ahead in Porsgrunn. 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 Porsgrunn viewing season.

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 Inverness, 830 km west in United Kingdom.

PorsgrunnInverness
Kp needed55
Nights per year21.6 28.7
Geomagnetic latitude59.1° 59.8°

See the Inverness forecast

Confirmed reports from this area

24 verified sightings were logged within 300 km of Porsgrunn 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 Porsgrunn

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 Porsgrunn.

Places from GeoNames (CC BY 4.0)

Where to stay

Anywhere on the outskirts of Porsgrunn will do; what matters is being able to step outside and check the sky without a drive first.

Places from GeoNames (CC BY 4.0) — confirm before booking

The last nights it was visible here

Nights in the last decade when the storm was strong enough for Porsgrunn and the sky was dark enough to show it.

DatePeak
2026-03-24Kp 5.0
2026-03-23Kp 5.0
2026-03-22Kp 6.67
2026-03-21Kp 6.0
2026-03-20Kp 7.0

NOAA planetary Kp

Know when it is worth going outside

Revon watches the Porsgrunn forecast and pushes an alert when the odds for tonight clear your threshold — no checking, no guessing.

Get aurora alerts on iPhone

Common questions about the aurora borealis in Porsgrunn

Can you see the aurora borealis from Porsgrunn?

Yes. On the last 10.0 years of NOAA Kp records, Porsgrunn had about 21.6 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 Porsgrunn?

Kp 5. Porsgrunn sits at geomagnetic latitude 59.1°, and the auroral oval only reaches that far from the pole once activity hits Kp 5. Storms that size occur about 28.7 nights a year.

When is the best time of year to see the aurora borealis in Porsgrunn?

September, March and October. 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 Porsgrunn never gets fully dark, so nothing is visible however strong the storm.

Where can you escape the light pollution near Porsgrunn?

The centre of Porsgrunn reads Bortle 5. The nearest sky at Bortle 4 is about 26 km west-north-west around Nome. On a marginal night that drive matters more than the forecast does.

Where is the nearest place to Porsgrunn with reliable aurora borealis?

Inverness, United Kingdom — 830 km west. It needs only Kp 5 and averages 28.7 viable nights a year against 21.6 in Porsgrunn.

Nearby towns

Forecasts for places within reach of Porsgrunn.