Aurora Borealis in Granby
Canada · 45.40°, -72.73° · geomagnetic 54.8° · needs Kp 7
Tonight in Granby
1%
Peak chance of a visible display tonight, from the same model the Revon app runs. Granby needs Kp 7 to see anything at all, and tonight the forecast peaks at Kp 5.1. Short of the threshold, which is what most nights look like here.
Updated 2026-08-02 20:20 UTC
The next 30 nights in Granby
Every night to come, scored the same way as tonight. The best of the open week is Sunday 2 Aug at 1%. Not one of the seven reaches the Kp 7 that Granby needs, which is normal rather than unlucky — it averages 3.2 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 Granby
3.2 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, Granby 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 11.4 | 10.3 | 8.9 | 6.9 | 4.8 | 3.1 | 3.9 | 6.1 | 8.2 | 9.9 | 11.1 | 11.7 |
Solar declination and hour angle at −18°
Getting clear of the light
The sky over Granby reads Bortle 6. Getting clear of the built-up area makes a visible difference on a marginal night.
- 21 km east-north-east — around Roxton → Bortle 5
- 86 km east-north-east — around Wotton → 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, May, September and August came out ahead in Granby. 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 Granby viewing season.
- 13 Aug 2026
- 11 Sep 2026
- 11 Oct 2026
- 09 Nov 2026
- 09 Dec 2026
- 07 Jan 2027
- 06 Feb 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 Nuuk, 2,459 km north-north-east in Greenland.
| Granby | Nuuk | |
|---|---|---|
| Kp needed | 7 | 3 |
| Nights per year | 3.2 | 171.4 |
| Geomagnetic latitude | 54.8° | 72.6° |
Confirmed reports from this area
87 verified sightings were logged within 300 km of Granby 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 Granby
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 Granby.
- Plage Darby — beach6.8 km east-north-east
- La Petite Baie — bay8.7 km north-east
- Lac Roxton — lake9.7 km north-east
- Plage Stanley — beach9.7 km north-east
- Île du Diable — island10.0 km north-east
- Île Bullock — island10.1 km 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 Granby 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 Granby forecast and pushes an alert when the odds for tonight clear your threshold — no checking, no guessing.
Common questions about the aurora borealis in Granby
Can you see the aurora borealis from Granby?
Yes. On the last 10.0 years of NOAA Kp records, Granby had about 3.2 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 Granby?
Kp 7. Granby sits at geomagnetic latitude 54.8°, 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 Granby?
May, September and August. Those months scored highest once both conditions are counted together: geomagnetic activity and enough hours of real darkness.
Where can you escape the light pollution near Granby?
The centre of Granby reads Bortle 6. The nearest sky at Bortle 4 is about 86 km east-north-east around Wotton. On a marginal night that drive matters more than the forecast does.
Where is the nearest place to Granby with reliable aurora borealis?
Nuuk, Greenland — 2,459 km north-north-east. It needs only Kp 3 and averages 171.4 viable nights a year against 3.2 in Granby.
Nearby towns
Forecasts for places within reach of Granby.