Billings, MT · magnetic latitude 53.5°
Northern lights in Billings: tonight’s chance
Montana’s largest city sits under the Rimrocks; the plains to the north give it a wide sky once you climb out of the valley.
Tonight at Billings, MT
…
Reading the SWPC Kp forecast and the cloud forecast…
| Kp forecast during the dark hours | not yet forecast |
|---|---|
| Kp needed here | 6.3 (G2 moderate) |
| Cloud cover in the dark hours | loading |
| Dark sky (Sun 18° down) | 8:10 PM to 5:50 AM MDT |
| Moon | 13% lit |
| Right now, OVATION (30 to 90 min) | loading or unavailable |
| Magnetic latitude (AACGM) | 53.5° |
Hour by hour, MDT
7 PM
Kp –
– ☁
No
8 PM
Kp –
– ☁
No
9 PM
Kp –
– ☁
No
10 PM
Kp –
– ☁
No
11 PM
Kp –
– ☁
No
12 AM
Kp –
– ☁
No
1 AM
Kp –
– ☁
No
2 AM
Kp –
– ☁
No
3 AM
Kp –
– ☁
No
4 AM
Kp –
– ☁
No
5 AM
Kp –
– ☁
No
6 AM
Kp –
– ☁
No
Rules checked · Built by Radif Partners · How the answer works
- Kp to see it from Billings
- 6.3
- Storm level needed
- G2 (Moderate)
- Kp for aurora overhead
- 6.3
- Most clear dark hours
- September
From Billings the northern lights need a planetary Kp of about 6.3, a G2 (Moderate) storm on the NOAA scale. In the AACGM model the city sits at 53.5 degrees magnetic latitude, a little less favorable than the Hi-Line towns, where Havre needs about 5.0, but better than cities of the same latitude farther east. The aurora reaches the zenith around Kp 6.3. Billings has two assets: the sandstone Rimrocks that rise above the north side of town give an elevated viewpoint over the plains, and the air is dry, with a NASA POWER cloud amount of 43% in July. The cloudiest month is February, at 74%. Counting clear dark hours, the product of night length and clear sky, September, November and October come first.
Above the Yellowstone valley
Billings spreads along the Yellowstone River beneath a line of sandstone cliffs, the Rimrocks, which rise a few hundred feet above downtown on the north side. For an aurora watcher that is a gift: from the top of the Rims the view runs north over the plains, and the lights of the city fall behind and below. At Kp 6.3, the aurora appears as a low arc over that northern horizon, and the extra height helps clear any haze in the valley.
North of the city the land empties quickly. The ranch country toward Roundup and the Musselshell has few lights, and on a G2 or G3 night it gives a dark, open sky within an hour's drive.
What Kp does this town need?
Kp to see aurora from here
6.3
| Magnetic latitude (AACGM) | 53.5° |
| Kp for aurora overhead | 6.3 |
| Storm level | G2 Moderate |
| How often that level comes | about 360 days per 11-year cycle |
View line: the more southern of the SWPC oval rule and the NOAA G scale latitudes at each Kp.
Weather on the plains
Billings sits in the lee of the Beartooth and Absaroka ranges, and Pacific moisture reaches it only after crossing several mountain chains. In NASA POWER averages the cloud amount runs from 43% in July to 74% in February. Chinook winds in winter can clear the sky fast and keep it clear for several nights, though they also bring gusts that make standing outside harder. The hour strip of the tool shows how the National Weather Service expects the sky to evolve through the night.
Winter nights on the rimrock
In mid-winter, the top of the Rims is exposed to the wind and the cold, and the nights are long: 11.7 hours of full darkness on December 15. A car parked facing north at a pullout along the rim is a practical observing post; the city glow sits behind and below, and the engine can stay off while you watch the sky. The hour strip of the tool shows the hours when the Kp forecast comes closest to Billings' threshold, which is when to be there.
How Billings compares
Billings and Missoula share almost the same threshold, 6.3 against 6.2, but Billings has the flatter horizon and the drier air. Sioux Falls and Rapid City, farther east, need about the same storm. For lower thresholds within the state the Hi-Line is the answer, as the Montana page shows; for the neighboring plains, see the North Dakota page and the Rapid City page.
Kp needed around Billings
| Town | Magnetic latitude | Kp to see it | Kp overhead | Storm level |
|---|---|---|---|---|
| Havre | 56.0° | 5.0 | 5.0 | G1 (Minor) |
| Kalispell | 54.9° | 5.6 | 5.6 | G1 (Minor) |
| Great Falls | 54.7° | 5.6 | 5.6 | G1 (Minor) |
| Missoula | 53.7° | 6.2 | 6.2 | G2 (Moderate) |
| Billings | 53.5° | 6.3 | 6.3 | G2 (Moderate) |
| Bozeman | 53.0° | 6.4 | 6.5 | G2 (Moderate) |
Darkness and clouds by month in Billings
| Month | Dark hours | Dark sky, 15th | Mean cloud | Clear dark hours |
|---|---|---|---|---|
| January | 11.4 h | 6:42 PM to 6:05 AM | 72% | 3.2 h |
| February | 10.2 h | 7:20 PM to 5:35 AM | 74% | 2.7 h |
| March | 8.8 h | 8:59 PM to 5:45 AM | 73% | 2.4 h |
| April | 6.8 h | 9:50 PM to 4:36 AM | 71% | 2.0 h |
| May | 4.6 h | 10:52 PM to 3:28 AM | 69% | 1.4 h |
| June | 3.0 h | 11:46 PM to 2:43 AM | 57% | 1.3 h |
| July | 3.8 h | 11:26 PM to 3:14 AM | 43% | 2.2 h |
| August | 6.0 h | 10:19 PM to 4:18 AM | 47% | 3.2 h |
| September | 8.1 h | 9:07 PM to 5:11 AM | 49% | 4.1 h |
| October | 9.8 h | 8:07 PM to 5:52 AM | 63% | 3.6 h |
| November | 11.1 h | 6:26 PM to 5:31 AM | 67% | 3.6 h |
| December | 11.7 h | 6:18 PM to 6:00 AM | 73% | 3.2 h |