Northern lights in Petersburg, Alaska
Little Norway's fishing fleet works under about 17.75 hours of midsummer daylight.
Petersburg
…Checking tonight's sky…
The next three nights
Geomagnetic activity (Kp) forecast for the selected town's dark hours. Kp runs 0–9; how much a town needs depends on its magnetic latitude. New to this? What the Kp index means, in plain words → Nights tagged “outlook” use NOAA’s 27-day outlook where the 3-day forecast doesn’t reach — whole-day values, so treat them as rougher estimates.
What Petersburg needs for a show
Whether aurora reaches a town is mostly a matter of magnetic latitude — distance from the magnetic pole, not the geographic one. Petersburg sits at magnetic latitude 60.4°, which puts it in the Kp 3 band: when the forecast Kp for the dark hours reaches about 3, the oval's southern edge reaches Petersburg and displays can appear low on the northern horizon. At Kp 5 or better, expect the band overhead at times. The same law draws the band on the homepage globe: the oval's edge at magnetic latitude 69 − 3×Kp.
| Magnetic latitude | 60.4° |
|---|---|
| Kp needed (horizon show) | About 3 |
| Kp for a strong overhead show | About 5+ |
| Coordinates | 56.8125°N, 132.9550°W · Southeast |
Kp is only one of four ingredients in the live call above: cloud cover over the dark hours, the town's actual darkness window, and moonlight all count too. A Kp 5 night under solid cloud is still a no — which is why the verdict, not the index, leads this page.
Petersburg’s aurora season
Petersburg has a real off-season: from about May 2 to Aug 10 (101 nights) the sun never dips 18° below the horizon, so it never gets truly dark and aurora can't be seen even when it's active. Outside that stretch, 264 nights in 2027 get a true-dark window.
| Month (2027) | True darkness | Typical dark window, mid-month |
|---|---|---|
| January | Every night | 11 hr 52 min |
| February | Every night | 10 hr 8 min |
| March | Every night | 7 hr 51 min |
| April | Every night | 4 hr 19 min |
| May | 1 of 31 nights | — |
| June | No true darkness | — |
| July | No true darkness | — |
| August | 21 of 31 nights | 2 hr 15 min |
| September | Every night | 6 hr 43 min |
| October | Every night | 9 hr 24 min |
| November | Every night | 11 hr 24 min |
| December | Every night | 12 hr 20 min |
True darkness = the sun below −18° (end of astronomical twilight), computed with the standard NOAA solar algorithm for Petersburg’s coordinates. The live call at the top of this page uses tonight's actual window, not these averages.
Petersburg in daylight
Sunrise, sunset, and daylight hours for Petersburg — today or any date — are on our sister site: Petersburg at Alaska Daylight →
On the water nearby
Night fishing or camping out of Petersburg? The nearest tide station is Petersburg (0 mi NNW) — tide predictions and minus tides at Alaska Tide Charts.