Best time to see the northern lights in Saint Mary's, United States
Updated • 19:57 UTC
Saint Mary's gets the aurora on 8.8 clear nights in a typical year. March is the best month at 1.55 of them, and nights were counted at Kp 4 or higher, which the planetary index last reached on 3 April 2026.
Typical-year figures: a 1996–2026 planetary Kp record crossed with a 2001–2020 cloud normal. They describe a normal year, not tonight — the live Saint Mary's forecast shows the actual cloud, moon and darkness right now. Check tonight's forecast for Saint Mary's →
🌌 Clear nights a year
8.8
Good — 8.8 clear aurora nights in a typical year Compare with United States
🌟 Best Month
March
1.55 clear nights in a typical year
🌙 Peak Hours
23:00-01:00
Magnetic midnight
⚡ Required Kp
Kp 5.0–7.0
Served for the live forecast; nights counted at Kp 4, last reached 3 April 2026
🧭 Auroral oval (model)
Overhead
Model estimate at Kp 4
Month by month in Saint Mary's
Astronomical darkness, the nights on which planetary Kp reached Kp 4 inside that darkness, the local cloud normal, and what the cloud leaves of the count.
| Month | Astronomical darkness | Opportunity nights | Mean cloud | Clear opportunity nights | Moon-free |
|---|---|---|---|---|---|
| January | 12.01h | 3.62 | 58.6% | 52.8% | |
| February | 9.96h | 3.42 | 64.6% | 53.9% | |
| March | 6.82h | 3.42 | 54.6% | 54.9% | |
| April | 3.06h on 45.8% of nights | 1.08 | 67.9% | 57.7% | |
| May | No astronomical darkness | — | 75% | — | — |
| June | No astronomical darkness | — | 74.9% | — | — |
| July | No astronomical darkness | — | 81.7% | — | — |
| August | 1.9h on 17.5% of nights | 0.36 | 78.1% | 57.1% | |
| September | 5.53h | 3.72 | 77.7% | 57.2% | |
| October | 9.16h | 4.76 | 80.3% | 54.3% | |
| November | 11.56h | 4.2 | 74.9% | 53.9% | |
| December | 12.68h | 3.91 | 65.9% | 54.3% |
May, June and July never reach astronomical darkness at Saint Mary's, so no Kp value makes them viewing months and they are excluded rather than scored.
Opportunity nights are the whole 1996–2026 record. In the current solar cycle alone (since 2023), March has averaged 6.24 rather than 3.42.
- March: 6.82h of astronomical darkness a night
- March: 3.42 nights reach the Kp threshold inside that darkness
- March: 54.6% mean cloud leaves 1.55 of them clear
- March: 54.9% of those nights are moon-free
Similar timing: Marshall , Russian Mission , Prince Albert
Higher-odds destinations: Fairbanks , Yellowknife , Tromsø
Nearby in Alaska
The strongest tracked locations in the same region, by clear aurora nights a year.
How these numbers were made
- Evaluated at
- Saint Mary's, 62.0556° N 163.1692° W — darkness and cloud are properties of that point, not of a region.
- Darkness
- Sun at or below 18° under the horizon (astronomical twilight), sampled every 10 minutes across every year of the Kp record and averaged per night of each month rather than on one representative day.
- Geomagnetic record
- GFZ Potsdam planetary Kp index, 3-hourly, 1996–2026 — 89,662 intervals, licensed CC BY 4.0.
- Cloud
- NASA POWER 20-year monthly climatology (2001–2020), parameter CLOUD_AMT. A monthly mean, not a forecast.
- Moon
- A night counts as moon-free below 35% lunar illumination while the moon is up.
- Auroral oval
- NOAA auroral-oval model, equatorward boundary near magnetic latitude 67 − 2 × Kp. A model estimate shown beside the measured record; it never replaces it.
- Clear opportunity nights
- Nights on which at least one 3-hour Kp interval falls inside local astronomical darkness and reaches the count threshold, scaled by one minus the monthly mean cloud amount.
- Kp threshold
- Nights were counted at Kp 4 or higher from the climatology's magnetic-latitude ladder; the Required Kp shown above, Kp 5, is the threshold the live Saint Mary's forecast serves from a corrected magnetic latitude, one step apart.
- Dataset version
- Version 2026-09-07, computed offline from the closed record — the page is regenerated, not forecast.
Kp record: GFZ Potsdam (CC BY 4.0). Cloud normal: NASA POWER. How the live forecast is built: methodology page.
Frequently Asked Questions
When can you see the northern lights in Saint Mary's?
March is the best month, with 1.55 clear nights in a typical year out of 8.8 across the whole year. Every month except May, June and July carries some chance. May, June and July never reach astronomical darkness, so no Kp value makes them viewing months.
What Kp is needed to see the aurora from Saint Mary's?
Saint Mary's needs Kp 5 or higher for aurora, Kp 6 for a noticeable display and Kp 7 for a bright one. The NOAA auroral-oval model places the oval overhead at Saint Mary's once the planetary index reaches Kp 4. That is a model estimate; the dates on this page come from the measured Kp record instead.
Has the aurora ever been visible from Saint Mary's?
Yes. In the 1996–2026 planetary Kp record the index reached Kp 4, the threshold these nights were counted at for Saint Mary's, most recently on 3 April 2026. The Kp 5 needed for a noticeable display was last reached on 22 March 2026. Whether anyone saw it also depended on the cloud, moonlight and darkness of that night, which the Kp record does not carry.
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