Aurora Borealis Calendar

Planning a northern lights trip requires understanding how aurora opportunity varies across every month of the year. This calendar rates each month on a combined score of geomagnetic activity probability, available darkness, and typical weather conditions at prime viewing destinations (65–70°N). Ratings are given on a 1–5 scale where 5 represents outstanding aurora conditions and 0 represents impossible viewing.

January — Rating: 4/5 | Darkness: ~18 hours at 69°N
Deep polar night. The sun does not rise above the Arctic Circle for most of January. Viewing windows are exceptionally long — in theory, you can see aurora at any time of day. Geomagnetic activity is moderate (mid-cycle, below equinox peaks), but solar maximum conditions in 2024–2026 elevate January considerably. Cold and occasionally cloudy in coastal regions; clearer in inland Lapland. Excellent month overall.

February — Rating: 5/5 | Darkness: ~15 hours at 69°N
Pre-equinox activity building. Polar night ending at lower Arctic latitudes — the first sunrise returns to Tromsø in mid-January, but February still has very long nights. February is frequently rated the clearest month at Abisko, Sweden. Cold (often -15°C to -25°C inland) but stable high-pressure dominated. Excellent geomagnetic activity as the spring equinox approaches. Top-tier month.

March — Rating: 5/5 | Darkness: ~10–12 hours at 69°N
Spring equinox peak. Statistically the highest geomagnetic storm frequency of the year. Still adequate darkness at prime latitudes. Snowscapes at their most beautiful. Weather generally improving from winter. The statistician's choice for best aurora month. Outstanding.

April — Rating: 3/5 | Darkness: ~6 hours at 69°N
Rapidly declining darkness. Post-equinox geomagnetic activity still elevated in early April, but night windows shrink to 4–6 hours by late April. Good for early-month trips at high latitudes; marginal by late April. Spring scenery and thawing landscapes.

May — Rating: 1/5 | Darkness: ~0–2 hours at 69°N
Season effectively over. Twilight all night by mid-May at Arctic latitudes. Only very early May at lower latitudes (60–63°N) retains a narrow window. Not recommended for aurora trips.

June — Rating: 0/5 | Darkness: 0 hours
Midnight sun. Impossible. The sun does not set at Arctic latitudes. Plan for hiking, midnight sun experiences, or southern hemisphere aurora in New Zealand and Tasmania instead.

July — Rating: 0/5 | Darkness: 0 hours
Midnight sun continues. No aurora viewing possible above 60°N.

August — Rating: 2/5 | Darkness: ~2–4 hours at 69°N (late August)
Season reopens late August. First dark nights return around August 20–25 at 69°N. Initial viewing windows are short, but late August has surprised aurora chasers with strong displays during geomagnetic storms. The aurora season opener.

September — Rating: 5/5 | Darkness: ~8–12 hours at 69°N
Autumn equinox peak. Equal to March in geomagnetic storm frequency. Spectacular autumn colours in the landscape. Comfortable temperatures. Less crowded than winter months. Outstanding month that is widely underrated.

October — Rating: 4/5 | Darkness: ~13–16 hours at 69°N
Strong aurora month with excellent darkness and post-equinox elevated activity. Autumn transitioning to early winter. Leaf-off trees improve sky views. Good cloud patterns at inland destinations. Excellent.

November — Rating: 4/5 | Darkness: ~17–20 hours at 69°N
Polar night beginning above the Arctic Circle (Tromsø loses the sun on November 27). Extensive darkness and frequent aurora. Coastal Norway can be the cloudiest month — inland Lapland significantly preferable. Very good overall.

December — Rating: 4/5 | Darkness: ~20+ hours at 69°N
Maximum darkness. Polar night at all Arctic Circle destinations. Christmas aurora ambiance unique. Cold and occasionally cloudy in coastal regions. The most atmospheric month for Arctic aurora tourism.

Several specific dates in the annual calendar are particularly significant for aurora planning. These are not arbitrary milestones — they are astronomical events with direct physical consequences for aurora frequency and viewing conditions.

Spring Equinox (around March 20–21): The most important single date in the aurora calendar. The spring equinox is the trigger for the Russell-McPherron geomagnetic enhancement, which produces statistically more storm days in the weeks around the equinox than any other period. The effect is centred on the equinox but extends approximately 2–3 weeks on either side — meaning the period from approximately March 1 to April 10 captures most of the equinox benefit. Aurora chasers targeting the spring equinox should aim for the two weeks straddling March 20.

Autumn Equinox (around September 22–23): The mirror image of the spring equinox in geomagnetic terms — equally powerful, and adding the unique backdrop of autumn foliage. The equinox geomagnetic enhancement extends from approximately September 5 to October 10. Combine this with the first adequate darkness of the season (available from mid-August) and September 15 to October 10 emerges as one of the most compelling aurora windows of the year.

Winter Solstice (around December 21–22): The shortest day and longest night of the year. The solstice itself has no special significance for geomagnetic activity — there is no "solstice effect" analogous to the equinox effect — but it marks the peak of darkness availability. From late November through late January, polar night dominates above 66.5°N (the Arctic Circle), providing the most viewing hours available in the annual cycle. Combine this extended darkness with any geomagnetic activity and aurora viewing opportunities multiply.

Summer Solstice (around June 21): The aurora dead zone peak. This is the date when midnight sun is most extreme at high latitudes. Ironically, the solstice marks the turning point — from the summer solstice, days gradually shorten and the aurora season's eventual return begins its countdown. Every day after June 21 moves you closer to the first dark nights of late August.

Polar Night Start/End Dates (latitude-specific): Polar night — when the sun does not rise at all — begins on different dates at different latitudes. At Tromsø (69.6°N), polar night runs from approximately November 27 to January 15 (about 7 weeks). At Svalbard (78°N), it runs from October 26 to February 15 (approximately 16 weeks). At the Arctic Circle (66.5°N), polar night lasts only a single day at the winter solstice. These dates frame the most intense darkness periods and are worth marking in your planning calendar. Learn more at the winter aurora guide.

27-Day Solar Rotation Windows: The sun rotates on its axis approximately every 27 days as seen from Earth. Active sunspot regions that produce strong aurora one week may return to face Earth again 27 days later — creating "recurrent geomagnetic storms" that aurora forecasters watch for. These are not as powerful or reliable as CME-driven storms, but they create probabilistic windows of elevated activity that repeat through the aurora season. During solar maximum, multiple active regions may be simultaneously facing Earth, removing much of the need to time trips around specific rotation windows.

Beyond the annual seasonal calendar, there is a shorter-term periodicity in geomagnetic activity that sophisticated aurora planners monitor: the 27-day solar rotation window. When a persistent active region on the sun — a coronal hole or active sunspot group — faces Earth, it sends an enhanced stream of solar wind that can trigger geomagnetic storms. If the region survives long enough on the sun's surface, it will rotate back into an Earth-facing position approximately 27 days later, potentially triggering another storm.

This 27-day pattern creates "recurrent geomagnetic storms" — a category tracked separately by space weather forecasters because of their relative predictability. Unlike CME-driven storms (which are essentially impossible to predict more than 3 days in advance), recurrent storms from long-lived coronal holes can sometimes be anticipated weeks ahead based on the known solar rotation period. NOAA's Space Weather Prediction Center regularly issues extended outlook products that flag upcoming recurrent activity windows.

During the current solar maximum, coronal holes have been particularly active and persistent. Several major coronal holes have completed multiple rotations while facing Earth, producing recurring enhancements of geomagnetic activity in the month following initial identification. Aurora alert services — including the notifications available through the aurora alerts page — can notify you when these windows are active.

For trip planners, the 27-day cycle offers a practical tool: if you experience a major geomagnetic storm during a scouting trip or research period, mark your calendar 27 days forward as a potential recurrence window. Success rates for recurrent storms are not guaranteed — the active region may decay or rotate away from optimal Earth-facing orientation — but the probability is elevated enough to factor into planning. Combine recurrent storm timing with the equinox calendar and you can identify particularly high-probability short windows for aurora trips.

The most powerful tool for real-time planning remains the live aurora forecast, which integrates satellite data from the DSCOVR spacecraft positioned at the L1 Lagrange point between Earth and the sun. This real-time data provides roughly 15–60 minutes of warning before solar wind changes reach Earth — enough time to get outside to a dark sky location if you are already in an aurora destination. Combine the forecast with the KP index guide to understand what numbers mean for visibility at your specific latitude.

While the general aurora calendar applies broadly across northern hemisphere destinations, each location has specific nuances of weather, darkness, and microclimate that modify the optimal travel window. Here are the key calendar considerations for the most popular aurora destinations.

Tromsø, Norway (69.6°N): Prime window is January–March and September–October. November and December are valid but tend to have the most cloud cover of the year. February is statistically the clearest month due to cold, dry continental air. Polar night runs November 27 to January 15. Summer solstice brings the midnight sun from May 18 to July 26. Best months overall: February and March.

Abisko, Sweden (68.4°N): Unique microclimate — the Scandinavian mountain range creates a rain shadow that gives Abisko dramatically lower cloud cover than coastal Norway. Any winter month is reliable here when activity levels are adequate. The Aurora Sky Station at Abisko is open October through March. The lack of cloud interference makes Abisko the most reliable single location in Scandinavia for clear-sky aurora viewing across all winter months.

Saariselkä, Finland (68.4°N): Finnish Lapland benefits from a continental interior climate with cold, dry, stable conditions from November through March. The glass igloo resorts operate October–April. Best months are January–March when stable high pressure dominates and temperatures drop to -20°C to -35°C. September–October is excellent for autumn aurora before the first snows, and March is excellent for spring aurora as snow conditions remain perfect.

Reykjavik, Iceland (64°N): Iceland's weather is famously unpredictable year-round, making any specific month only marginally better than others from a weather perspective. Darkness is adequate from September through March. The equinox months (September–October and February–March) provide the best combination of adequate darkness and elevated geomagnetic activity for this latitude (which requires KP 3–4 for visible displays from Reykjavik). Rent a car and be prepared to drive to clear skies.

Yellowknife, Canada (62.5°N): Benefits from the offset magnetic pole, which places Yellowknife directly beneath the auroral oval despite its relatively southerly latitude. The continental climate delivers very cold but very clear winters. January and February are outstanding months here. The city's dedicated aurora tourism infrastructure (viewing pods, guided tours, aurora forecasting services) makes it the most accessible North American aurora destination. Best months: December through February, with excellent conditions extending into early March.