Northern lights in Yellowknife in September
One of the best months of the year — 59% of September nights offer a real window.
The numbers behind it: September nights in Yellowknife average about 8 dark hours, geomagnetic activity reaches local viewing levels on 99% of days, and 60% of nights offer at least one reasonably clear hour after dark.
Neither clouds nor solar activity dominates — September failures are usually bad single-night luck. Several nights in a row is the honest insurance policy.
September also benefits from the equinox effect: around the equinoxes the Earth's magnetic field couples more efficiently with the solar wind (the Russell-McPherron effect), and 30 years of records show measurably more active days than in midwinter.
Numbers come from 1996–2025 Kp records (GFZ Potsdam) and 2015–2024 hourly cloud history for Yellowknife itself — the full method is on the methodology page. Travelling soon? Check tonight's live Yellowknife forecast.
September against the rest of the year
- Jan54% of nights
- Feb65% of nights
- Mar61% of nights
- Apr59% of nights
- May10% of nights
- Junmidnight sun
- Julmidnight sun
- Aug50% of nights
- Sep59% of nights
- Oct41% of nights
- Nov35% of nights
- Dec47% of nights
August in Yellowknife · October in Yellowknife · full year overview