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Northern lights Great Falls tonight

Great Falls sits at 56° magnetic latitude in north-central Montana - the highest of any named Montana city on this site. The threshold here is Kp 3-4, lower than Bozeman or Whitefish. Flat plains to the north mean dark sky extends without obstruction toward Canada. Giant Springs State Park is 3 miles from downtown. Best season: September to April.

Aurora visibility - Great Falls

Unlikely tonight

Kp 1 is well below the Kp 3–4 threshold needed for aurora to be visible from Great Falls.

Current Kp

of 9

Threshold for Great Falls: Kp 3–4 Magnetic latitude: ~56°N Updated: 15 May, 17:59 UTC

↓ Bz — nT Solar wind — km/s Density — p/cm³ ☁ —%

Conditions right now: — Kp + Bz + solar wind + cloud + moon

7-day outlook for Great Falls

Today

15 May

Quiet

Tomorrow

16 May

Quiet

Sun

17 May

Quiet

Mon

18 May

Quiet

Tue

19 May

Quiet

Wed

20 May

Quiet

Thu

21 May

Quiet

Based on CME arrival predictions from NASA DONKI. Arrival times ±6 hours.

What Kp is needed here?

Great Falls sits at a magnetic latitude of approximately 56°N. The Kp index - a global measure of geomagnetic activity on a scale from 0 (quiet) to 9 (extreme storm), updated every 3 hours - needs to reach Kp 3–4 before the auroral oval expands far enough south to be visible from here.

At Kp 3–4, visibility is possible from Great Falls but skies need to be clear and dark. Cloud cover and light pollution remain the main obstacles even when Kp is high enough.

Best dark sky sites near Great Falls

Light pollution is the biggest obstacle after cloud cover. These sites give you the best dark northern horizon within reach.

Giant Springs State Park

3 miles northeast of downtown along the Missouri River. The north-facing position sits east of the city light dome, with the river cottonwood corridor absorbing the ambient glow from downtown. Open land extends north toward Canada with minimal settlements. One of the closest genuinely dark positions to Great Falls's city center.

Belt Creek canyon

30 miles southeast via US-89 toward Monarch in the Little Belt Mountains. The canyon terrain drops into Bortle 3 conditions quickly once you leave the plains. The elevated mountain terrain provides a dark sky above the surrounding plateau, and the creek valley itself blocks most horizon-level light from the city. The drive on US-89 passes through open range with no towns between Great Falls and Monarch.

Highwood Mountains

35 miles east of Great Falls off US-87. The isolated range rises above the surrounding plains with Bortle 2-3 conditions on the north side of the range. The elevation gain above the flatlands removes any residual light from Great Falls entirely. Forest Service roads in summer access the upper elevations. The plains-to-mountain transition makes this one of the more distinctive visual foregrounds in north-central Montana.

Best time to see the northern lights in Great Falls

Great Falls's aurora season runs from late September through to March, when nights are long enough for truly dark skies. The equinox months, September and March, bring a natural boost in geomagnetic activity, making them statistically the best of the season. Summer months bring too much twilight for aurora to be visible at this latitude.

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Activity peaks around the September and March equinoxes, when Earth's magnetic field geometry is most favourable for coupling with the solar wind. Events during these two windows tend to produce the strongest displays of the year for observers at Great Falls's latitude.

April through August brings persistent astronomical twilight that washes out aurora completely. Even strong events (Kp 6+) remain invisible during this period because the sky never gets dark enough.

Other USA aurora forecasts

← USA overview

Whitefish

Unlikely

Glacier National Park gateway, NW Montana

~55°N mag. lat. Kp 4

Bozeman

Unlikely

Gallatin Valley, Yellowstone gateway, Montana

~54°N mag. lat. Kp 4

Montana

Unlikely

Glacier NP, Rocky Mountain aurora

~55°N mag. lat. Kp 4-5

Northern Lights USA

USA-wide aurora forecast hub.

Northern Lights Whitefish Tonight

Whitefish - Glacier National Park access at 55° magnetic latitude.

Northern Lights Bozeman Tonight

Bozeman - Gallatin Valley dark sky at 54° magnetic latitude.

Northern Lights Montana

Montana statewide aurora forecast and dark sky guide.

What Is the Kp Index?

What Kp 3-4 means for aurora viewing at 56° magnetic latitude.

Common questions

Aurora watching from Great Falls and north-central Montana.

Why is Great Falls particularly well-positioned for aurora?

Three factors combine here. Great Falls sits at about 56° magnetic latitude - higher than Bozeman (54°) or Whitefish (55°) - which lowers the Kp threshold for visible aurora to Kp 3-4. The surrounding terrain is flat plains with minimal light pollution in any direction except within the city itself, so aurora low on the northern horizon is not obscured by topography. The city is also small enough that driving 3 to 5 miles north places you in genuinely dark conditions. Few mid-sized American cities combine this latitude, this little surrounding light pollution, and this easy access to dark sky.

What Kp is needed for aurora in Great Falls?

Great Falls sits at about 56° magnetic latitude, which lowers the threshold to Kp 3-4. The Kp index is a global measure of geomagnetic activity on a scale from 0 (quiet) to 9 (extreme storm), updated every 3 hours. At Kp 3, faint aurora is plausible from the darkest spots north of the city on clear nights. Kp 4 produces reliable visible displays, and Kp 5 or above typically brings overhead activity with clear color differentiation. This threshold is notably lower than most continental US cities south of the Canadian border.

What are the best dark sky spots within an hour of Great Falls?

Giant Springs State Park, just 3 miles northeast of downtown, is the most immediate option - it faces north with the Missouri River corridor blocking the city glow. The Belt Creek canyon south on US-89 is excellent within 30 miles, reaching Bortle 3 quickly in the mountain terrain. The Highwood Mountains to the east offer Bortle 2-3 on north-facing slopes and are worth the 35-mile drive for a predicted strong event. US-89 north toward Fort Benton - about 40 miles - gives open plains with exceptional flat northern horizon and Bortle 2-3 conditions.

How does Great Falls compare to Bozeman and Whitefish for aurora?

Great Falls has the highest magnetic latitude of the three, giving it the lowest Kp threshold. At Kp 3, Great Falls can see faint aurora when Bozeman and Whitefish at Kp 4 might not. The tradeoff is scenery - Bozeman has mountain dark sky at Hyalite Canyon, and Whitefish has Glacier National Park immediately adjacent. Great Falls aurora viewing is primarily flat plains observation, which maximizes sky coverage but lacks the mountain foreground of the other two cities. For frequency of events and ease of dark sky access, Great Falls has a real edge.

How often does aurora appear over Great Falls?

At 56° magnetic latitude, Great Falls sees Kp 3 or higher events on roughly 40-60 nights per year during solar maximum. That is higher than most continental US cities. The plains location also gives good sky clarity - Great Falls averages around 220 clear nights per year, more than most Pacific-influenced western cities. The result is a higher number of actual visible-aurora nights than nearly any other city in the lower 48 outside of the northern tier of the Great Plains. The peak months are March through April and September through October.