Grand Rapids, MI · magnetic latitude 52.3°
Northern lights in Grand Rapids: tonight’s chance
Grand Rapids sits inland from Lake Michigan, close enough to catch its lake-effect cloud and far enough that the water is no help on the northern horizon.
Tonight at Grand Rapids, MI
…
Reading the SWPC Kp forecast and the cloud forecast…
| Kp forecast during the dark hours | not yet forecast |
|---|---|
| Kp needed here | 6.5 (G2 moderate) |
| Cloud cover in the dark hours | loading |
| Dark sky (Sun 18° down) | 8:37 PM to 6:20 AM EDT |
| Moon | 13% lit |
| Right now, OVATION (30 to 90 min) | loading or unavailable |
| Magnetic latitude (AACGM) | 52.3° |
Hour by hour, EDT
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 Grand Rapids
- 6.5
- Storm level needed
- G2 (Moderate)
- Kp for aurora overhead
- 6.9
- Most clear dark hours
- September
Grand Rapids needs a planetary Kp of about 6.5 to see the northern lights, a G2 (Moderate) storm on the NOAA scale. At 52.3 degrees magnetic latitude in the AACGM model it sits a little north of Detroit, which needs Kp 6.7, and well south of Traverse City, which needs about Kp 6.0. The oval would reach overhead around Kp 6.9. West Michigan's weather is the real filter: the NASA POWER cloud average for Grand Rapids peaks at 82% in December, when lake-effect cloud sits over the region for days, and drops to about 49% in high summer. Darkness on the 15th lasts 11.6 hours in December against 4.1 in June. Combining the two, September, October and August give the most clear dark hours, which makes late summer and early autumn the season to watch. The tool below checks tonight's Kp forecast against hourly NWS sky cover for Grand Rapids.
Near a lake whose shore faces the wrong way
Grand Rapids grew up on the Grand River, inland from Lake Michigan, and the lake shapes its sky without ever giving it a view. The beaches at Grand Haven and Holland face west, toward Wisconsin, so the open water there sits to the left of an aurora watcher looking north, and the northern horizon runs along a coastline of dunes and towns. Inland, the city's own glow fills the northern sky from most neighborhoods. The useful move is north on US 131 or the back roads toward the Muskegon River country, where farmland gives way to forest and the lights thin out quickly.
That drive also changes the numbers. Grand Rapids needs about Kp 6.5; by the time you reach Traverse City the threshold is down to Kp 6.0, 0.5 Kp lower, and the Marquette page shows how far the bar falls by Lake Superior.
A moderate storm city
West Michigan sits right at the line where the second level of the NOAA scale starts to deliver. At 52.3 degrees magnetic latitude, a G2 (Moderate) storm lifts the aurora just above the northern horizon in the view line this site uses, and the margin between seeing and missing it is small. A storm that just touches Kp 6.5 for one three-hour block may show only to a camera; one that holds Kp 7 through the evening is a different night, and around Kp 6.9 the oval would come overhead. Detroit, on the other side of the state, needs a full G3 (Strong) storm, so Grand Rapids gets slightly better odds on the same night.
How dark, how clear: one town, one month
Hours of full darkness on the 15th
6.5 h
| Dark sky | 10:33 PM to 5:00 AM |
| Including nautical twilight | 7.8 h |
| Mean cloud amount (NASA POWER) | 49% |
| Clear dark hours on an average night | 3.3 h |
Computed for 2027; the hours move by a few minutes from one year to the next.
The lake-effect season and the summer window
From November into February, west Michigan lives under lake-effect cloud. NASA POWER's averages show it: December reaches 82% cloud amount in Grand Rapids, and the longest nights of the year are mostly overcast. The clearer half of the year starts in summer, when the lake is warm and the air stable, but June nights are short, with full darkness from 11:41 PM to 3:45 AM on the 15th. August is the compromise, with 6.5 dark hours and a cloud amount near 49%, and September adds more darkness at similar cloud. A strong storm in late summer, after midnight, is the best realistic chance here. The Michigan page compares the rest of the state.
Kp needed around Grand Rapids
| Town | Magnetic latitude | Kp to see it | Kp overhead | Storm level |
|---|---|---|---|---|
| Houghton | 56.3° | 4.9 | 4.9 | G1 (Minor) |
| Marquette | 55.7° | 5.1 | 5.1 | G1 (Minor) |
| Sault Ste. Marie | 55.6° | 5.2 | 5.2 | G1 (Minor) |
| Traverse City | 54.0° | 6.0 | 6.0 | G2 (Moderate) |
| Grand Rapids | 52.3° | 6.5 | 6.9 | G2 (Moderate) |
| Lansing | 52.0° | 6.6 | 7.0 | G2 (Moderate) |
| Detroit | 51.6° | 6.7 | 7.2 | G3 (Strong) |
Darkness and clouds by month in Grand Rapids
| Month | Dark hours | Dark sky, 15th | Mean cloud | Clear dark hours |
|---|---|---|---|---|
| January | 11.3 h | 7:13 PM to 6:30 AM | 80% | 2.3 h |
| February | 10.2 h | 7:49 PM to 6:03 AM | 75% | 2.5 h |
| March | 8.9 h | 9:23 PM to 6:18 AM | 67% | 3.0 h |
| April | 7.1 h | 10:08 PM to 5:16 AM | 63% | 2.6 h |
| May | 5.3 h | 10:59 PM to 4:17 AM | 64% | 1.9 h |
| June | 4.1 h | 11:41 PM to 3:45 AM | 56% | 1.8 h |
| July | 4.7 h | 11:28 PM to 4:09 AM | 49% | 2.4 h |
| August | 6.5 h | 10:33 PM to 5:00 AM | 49% | 3.3 h |
| September | 8.3 h | 9:29 PM to 5:46 AM | 50% | 4.2 h |
| October | 9.8 h | 8:34 PM to 6:22 AM | 64% | 3.5 h |
| November | 11.0 h | 6:57 PM to 5:57 AM | 71% | 3.2 h |
| December | 11.6 h | 6:51 PM to 6:24 AM | 82% | 2.0 h |