S85 Big Sky Field night times
Culbertson, MT
Night of Nov 6 to Nov 7MST
Position lights
§ 91.2094:31 PMto6:53 AM
Sunset to sunrise. Lights on.
2331Z to 1353Z
Night logging
§ 1.15:04 PMto6:20 AM
Civil twilight. Log it as night.
0004Z to 1320Z
Night currency
§ 61.57(b)5:31 PMto5:53 AM
One hour after sunset. Landings count.
0031Z to 1253Z
Evenings at S85
When each night begins, through the year. Local time.
| Date | SunsetLights on | Civil twilight endsLog night | 1 hr after sunsetLandings count |
|---|---|---|---|
| Nov 1MST | 4:39 PM | 5:12 PM | 5:39 PM |
| Nov 15MST | 4:20 PM | 4:54 PM | 5:20 PM |
| Dec 1MST | 4:06 PM | 4:42 PM | 5:06 PM |
| Dec 15MST | 4:05 PM | 4:41 PM | 5:05 PM |
| Jan 1MST | 4:15 PM | 4:51 PM | 5:15 PM |
| Jan 15MST | 4:32 PM | 5:07 PM | 5:32 PM |
| Feb 1MST | 4:58 PM | 5:31 PM | 5:58 PM |
| Feb 15MST | 5:20 PM | 5:52 PM | 6:20 PM |
| Mar 1MST | 5:42 PM | 6:13 PM | 6:42 PM |
| Mar 15MDT | 7:03 PM | 7:34 PM | 8:03 PM |
| Apr 1MDT | 7:28 PM | 8:00 PM | 8:28 PM |
| Apr 15MDT | 7:49 PM | 8:21 PM | 8:49 PM |
| May 1MDT | 8:12 PM | 8:47 PM | 9:12 PM |
| May 15MDT | 8:31 PM | 9:08 PM | 9:31 PM |
| Jun 1MDT | 8:50 PM | 9:30 PM | 9:50 PM |
| Jun 15MDT | 9:00 PM | 9:41 PM | 10:00 PM |
| Jul 1MDT | 9:02 PM | 9:43 PM | 10:02 PM |
| Jul 15MDT | 8:54 PM | 9:33 PM | 9:54 PM |
| Aug 1MDT | 8:34 PM | 9:11 PM | 9:34 PM |
| Aug 15MDT | 8:12 PM | 8:46 PM | 9:12 PM |
| Sep 1MDT | 7:39 PM | 8:12 PM | 8:39 PM |
| Sep 15MDT | 7:11 PM | 7:42 PM | 8:11 PM |
| Oct 1MDT | 6:37 PM | 7:08 PM | 7:37 PM |
| Oct 15MDT | 6:09 PM | 6:41 PM | 7:09 PM |
Mornings at S85
When each night ends. Local time.
| Date | 1 hr before sunriseLandings stop counting | Civil twilight beginsNight logging ends | SunriseLights off |
|---|---|---|---|
| Nov 1MST | 5:44 AM | 6:11 AM | 6:44 AM |
| Nov 15MST | 6:05 AM | 6:31 AM | 7:05 AM |
| Dec 1MST | 6:28 AM | 6:52 AM | 7:28 AM |
| Dec 15MST | 6:42 AM | 7:05 AM | 7:42 AM |
| Jan 1MST | 6:49 AM | 7:12 AM | 7:49 AM |
| Jan 15MST | 6:44 AM | 7:08 AM | 7:44 AM |
| Feb 1MST | 6:26 AM | 6:53 AM | 7:26 AM |
| Feb 15MST | 6:05 AM | 6:33 AM | 7:05 AM |
| Mar 1MST | 5:39 AM | 6:08 AM | 6:39 AM |
| Mar 15MDT | 6:11 AM | 6:40 AM | 7:11 AM |
| Apr 1MDT | 5:36 AM | 6:05 AM | 6:36 AM |
| Apr 15MDT | 5:09 AM | 5:36 AM | 6:09 AM |
| May 1MDT | 4:40 AM | 5:05 AM | 5:40 AM |
| May 15MDT | 4:19 AM | 4:42 AM | 5:19 AM |
| Jun 1MDT | 4:02 AM | 4:22 AM | 5:02 AM |
| Jun 15MDT | 3:57 AM | 4:16 AM | 4:57 AM |
| Jul 1MDT | 4:02 AM | 4:21 AM | 5:02 AM |
| Jul 15MDT | 4:14 AM | 4:34 AM | 5:14 AM |
| Aug 1MDT | 4:34 AM | 4:57 AM | 5:34 AM |
| Aug 15MDT | 4:52 AM | 5:18 AM | 5:52 AM |
| Sep 1MDT | 5:16 AM | 5:43 AM | 6:16 AM |
| Sep 15MDT | 5:35 AM | 6:04 AM | 6:35 AM |
| Oct 1MDT | 5:57 AM | 6:26 AM | 6:57 AM |
| Oct 15MDT | 6:17 AM | 6:46 AM | 7:17 AM |
Lights and runways
As the FAA lists them. NOTAMs aren't included, so check current NOTAMs before you fly.
ACTVT MIRL RY 08/26 & PAPI RY 26 - CTAF.
Runway 08/26
3,800 × 60 ft · Asphalt
Frequencies
Night at S85, in short
When can I log night time at S85?
From the end of evening civil twilight to the beginning of morning civil twilight, when the sun is 6° below the horizon (14 CFR 1.1). On the night of Nov 6, 2026, that was 5:04 PM to 6:20 AM MST.
When do landings at S85 count for night currency?
From one hour after sunset to one hour before sunrise. To carry passengers at night you need 3 takeoffs and 3 full-stop landings in that period within the last 90 days (14 CFR 61.57(b)). On the night of Nov 6, 2026, that was 5:31 PM to 5:53 AM MST.
When are position lights required at S85?
From sunset to sunrise (14 CFR 91.209(a)). On the night of Nov 6, 2026, that was 4:31 PM to 6:53 AM MST.
Nearby airports
- 5U6 Fairview Fairview, MT · 25 nm
- PO1 Poplar Municipal Poplar, MT · 26 nm
- KSDY Sidney-Richland Regional Sidney, MT · 30 nm
- KXWA Williston Basin International Williston, ND · 31 nm
- KPWD Sher-Wood Plentywood, MT · 38 nm
- 7U8 Richey Richey, MT · 39 nm
Times are worked out from the sun's position for a sea-level horizon, rounded to the minute. Airport data from the FAA NASR cycle of Oct 29, 2026.