Boulder Colorado: Sunrise/Sunset data and length of twilight
Go to Length of Twilight Table Add 1 hour to sunrise/sunset times for daylight savings time. Typically, it starts in March and ends in November.Lengths of day computed from sunset/sunrise times and are subject to rounding errors.
January
Sunrise Sunset Length-of-Day 1 7:21 4:46 9:25 2 7:21 4:47 9:26 3 7:21 4:48 9:27 4 7:21 4:49 9:28 5 7:21 4:50 9:29 6 7:21 4:50 9:29 7 7:21 4:51 9:30 8 7:21 4:52 9:31 9 7:21 4:52 9:31 10 7:21 4:53 9:32 11 7:21 4:55 9:34 12 7:21 4:56 9:35 13 7:20 4:57 9:37 14 7:20 4:59 9:39 15 7:20 5:00 9:40 16 7:19 5:01 9:42 17 7:19 5:02 9:43 18 7:18 5:03 9:45 19 7:18 5:04 9:46 20 7:17 5:05 9:48 21 7:17 5:06 9:49 22 7:16 5:08 9:52 23 7:15 5:09 9:54 24 7:15 5:10 9:55 25 7:14 5:11 9:57 26 7:13 5:12 9:59 27 7:13 5:13 10:00 28 7:12 5:15 10:03 29 7:11 5:16 10:05 30 7:10 5:17 10:07 31 7:09 5:18 10:09Back to top
February
Sunrise Sunset Length-of-Day 1 7:08 5:19 10:11 2 7:07 5:21 10:14 3 7:07 5:22 10:15 4 7:06 5:23 10:17 5 7:05 5:24 10:19 6 7:03 5:25 10:22 7 7:02 5:27 10:25 8 7:01 5:28 10:27 9 7:00 5:29 10:29 10 6:59 5:30 10:31 11 6:58 5:31 10:33 12 6:57 5:32 10:35 13 6:56 5:34 10:38 14 6:54 5:35 10:41 15 6:53 5:36 10:43 16 6:52 5:37 10:45 17 6:50 5:38 10:48 18 6:49 5:39 10:50 19 6:48 5:41 10:53 20 6:47 5:42 10:55 21 6:45 5:43 10:58 22 6:44 5:44 11:00 23 6:42 5:45 11:03 24 6:41 5:46 11:05 25 6:40 5:47 11:07 26 6:38 5:48 11:10 27 6:37 5:50 11:13 28 6:35 5:51 11:16 29 6:35 5:52 11:17Back to top
March
Sunrise Sunset Length-of-Day 1 6:34 5:52 11:18 2 6:32 5:53 11:21 3 6:31 5:54 11:23 4 6:29 5:55 11:26 5 6:28 5:56 11:28 6 6:26 5:57 11:31 7 6:25 5:58 11:33 8 6:23 5:59 11:36 9 6:22 6:00 11:38 10 6:20 6:01 11:41 11 6:18 6:02 11:44 12 6:17 6:03 11:46 13 6:15 6:04 11:49 14 6:14 6:06 11:52 15 6:12 6:07 11:55 16 6:11 6:08 11:57 17 6:09 6:09 12:00 18 6:07 6:10 12:03 19 6:06 6:11 12:05 20 6:04 6:12 12:08 21 6:01 6:13 12:12 22 6:01 6:14 12:13 23 5:59 6:15 12:16 24 5:58 6:16 12:18 25 5:56 6:17 12:21 26 5:54 6:18 12:24 27 5:53 6:19 12:26 28 5:51 6:20 12:29 29 5:50 6:21 12:31 30 5:48 6:22 12:34 31 5:46 6:23 12:37Back to top
April
Sunrise Sunset Length-of-Day 1 5:45 6:24 12:39 2 5:43 6:25 12:42 3 5:42 6:26 12:44 4 5:40 6:27 12:47 5 5:38 6:28 12:50 6 5:37 6:29 12:52 *daylight savings time starts 1997 7 5:35 6:30 12:55 8 5:34 6:31 12:57 9 5:32 6:32 13:00 10 5:31 6:33 13:02 11 5:29 6:34 13:05 12 5:28 6:35 13:07 13 5:26 6:36 13:10 14 5:25 6:37 13:12 15 5:23 6:38 13:15 16 5:22 6:39 13:17 17 5:20 6:40 13:20 18 5:19 6:41 13:22 19 5:17 6:42 13:25 20 5:16 6:43 13:27 21 5:14 6:44 13:30 22 5:13 6:45 13:32 23 5:12 6:46 13:34 24 5:10 6:47 13:37 25 5:09 6:48 13:39 26 5:07 6:49 13:42 27 5:06 6:50 13:44 28 5:05 6:51 13:46 29 5:04 6:52 13:48 30 5:02 6:53 13:51Back to top
May
Sunrise Sunset Length-of-Day 1 5:01 6:54 13:53 2 5:00 6:55 13:55 3 4:59 6:56 13:57 4 4:57 6:57 14:00 5 4:56 6:58 14:02 6 4:55 6:59 14:04 7 4:54 7:00 14:06 8 4:53 7:01 14:08 9 4:52 7:02 14:10 10 4:51 7:03 14:12 11 4:50 7:04 14:14 12 4:49 7:05 14:16 13 4:48 7:06 14:18 14 4:47 7:06 14:19 15 4:46 7:07 14:21 16 4:45 7:08 14:23 17 4:44 7:09 14:25 18 4:43 7:10 14:27 19 4:42 7:11 14:29 20 4:41 7:12 14:31 21 4:41 7:13 14:32 22 4:40 7:14 14:34 23 4:39 7:15 14:36 24 4:38 7:15 14:37 25 4:38 7:16 14:38 26 4:37 7:17 14:40 27 4:37 7:18 14:41 28 4:36 7:19 14:43 29 4:35 7:19 14:44 30 4:35 7:20 14:45 31 4:34 7:21 14:47Back to top
June
Sunrise Sunset Length-of-Day 1 4:34 7:22 14:48 2 4:34 7:22 14:48 3 4:33 7:23 14:50 4 4:33 7:24 14:51 5 4:33 7:24 14:51 6 4:32 7:25 14:53 7 4:32 7:26 14:54 8 4:32 7:26 14:54 9 4:32 7:27 14:55 10 4:32 7:27 14:55 11 4:31 7:28 14:57 12 4:31 7:28 14:57 13 4:31 7:29 14:58 14 4:31 7:29 14:58 15 4:31 7:30 14:59 16 4:31 7:30 14:59 17 4:31 7:30 14:59 18 4:31 7:31 15:00 19 4:32 7:31 14:59 20 4:32 7:31 14:59 21 4:32 7:31 14:59 22 4:32 7:32 15:00 23 4:32 7:32 15:00 24 4:33 7:32 14:59 25 4:33 7:32 14:59 26 4:33 7:32 14:59 27 4:34 7:32 14:58 28 4:34 7:32 14:58 29 4:34 7:32 14:58 30 4:35 7:32 14:57Back to top
July
Sunrise Sunset Length-of-Day 1 4:35 7:32 14:57 2 4:36 7:32 14:56 3 4:36 7:32 14:56 4 4:37 7:31 14:54 5 4:37 7:31 14:54 6 4:38 7:31 14:53 7 4:39 7:31 14:52 8 4:39 7:30 14:51 9 4:40 7:30 14:50 10 4:41 7:30 14:49 11 4:41 7:29 14:48 12 4:42 7:29 14:47 13 4:43 7:28 14:45 14 4:43 7:28 14:45 15 4:44 7:27 14:43 16 4:45 7:27 14:42 17 4:46 7:26 14:40 18 4:46 7:25 14:39 19 4:47 7:25 14:38 20 4:48 7:24 14:36 21 4:49 7:23 14:34 22 4:50 7:23 14:33 23 4:51 7:22 14:31 24 4:51 7:21 14:30 25 4:52 7:20 14:28 26 4:53 7:19 14:26 27 4:54 7:18 14:24 28 4:55 7:17 14:22 29 4:56 7:16 14:20 30 4:57 7:15 14:18 31 4:58 7:14 14:16Back to top
August
Sunrise Sunset Length-of-Day 1 4:58 7:13 14:15 2 4:59 7:12 14:13 3 5:00 7:11 14:11 4 5:01 7:10 14:09 5 5:02 7:09 14:07 6 5:03 7:08 14:05 7 5:04 7:07 14:03 8 5:05 7:06 14:01 9 5:06 7:04 13:58 10 5:07 7:03 13:56 11 5:08 7:02 13:54 12 5:09 7:01 13:52 13 5:10 6:59 13:49 14 5:11 6:58 13:47 15 5:12 6:57 13:45 16 5:13 6:55 13:42 17 5:13 6:54 13:41 18 5:14 6:53 13:39 19 5:15 6:51 13:36 20 5:16 6:50 13:34 21 5:17 6:48 13:31 22 5:18 6:47 13:29 23 5:19 6:45 13:26 24 5:20 6:44 13:24 25 5:21 6:42 13:21 26 5:22 6:41 13:19 27 5:23 6:39 13:16 28 5:24 6:38 13:14 29 5:25 6:36 13:11 30 5:26 6:35 13:09 31 5:27 6:33 13:06Back to top
September
Sunrise Sunset Length-of-Day 1 5:28 6:32 13:04 2 5:28 6:30 13:02 3 5:29 6:29 13:00 4 5:30 6:27 12:57 5 5:31 6:25 12:54 6 5:32 6:24 12:52 7 5:33 6:22 12:49 8 5:34 6:21 12:47 9 5:35 6:19 12:44 10 5:36 6:17 12:41 11 5:37 6:16 12:39 12 5:38 6:14 12:36 13 5:39 6:12 12:33 14 5:40 6:11 12:31 15 5:41 6:09 12:28 16 5:42 6:08 12:26 17 5:42 6:06 12:24 18 5:43 6:04 12:21 19 5:44 6:03 12:19 20 5:45 6:01 12:16 21 5:46 5:59 12:13 22 5:47 5:58 12:11 23 5:48 5:56 12:08 24 5:49 5:54 12:05 25 5:50 5:53 12:03 26 5:51 5:51 12:00 27 5:52 5:50 11:58 28 5:53 5:48 11:55 29 5:54 5:46 11:52 30 5:55 5:45 11:50Back to top
October
Sunrise Sunset Length-of-Day 1 5:56 5:43 11:47 2 5:57 5:41 11:44 3 5:58 5:40 11:42 4 5:59 5:38 11:39 5 6:00 5:37 11:37 6 6:01 5:35 11:34 7 6:02 5:33 11:31 8 6:03 5:32 11:29 9 6:04 5:30 11:26 10 6:05 5:29 11:24 11 6:06 5:27 11:21 12 6:07 5:26 11:19 13 6:08 5:24 11:16 14 6:09 5:23 11:14 15 6:10 5:21 11:11 16 6:11 5:20 11:09 17 6:12 5:18 11:06 18 6:13 5:17 11:04 19 6:14 5:15 11:01 20 6:15 5:14 10:59 21 6:16 5:13 10:57 22 6:17 5:11 10:54 23 6:18 5:10 10:52 24 6:19 5:09 10:50 25 6:20 5:07 10:47 26 6:22 5:06 10:44 27 6:23 5:05 10:42 28 6:24 5:03 10:39 29 6:25 5:02 10:37 30 6:26 5:01 10:35 31 6:27 5:00 10:33Back to top
November
Sunrise Sunset Length-of-Day 1 6:28 4:58 10:30 2 6:29 4:57 10:28 3 6:31 4:56 10:25 4 6:32 4:55 10:23 5 6:33 4:54 10:21 6 6:34 4:53 10:19 7 6:35 4:52 10:17 8 6:36 4:51 10:15 9 6:37 4:50 10:13 10 6:39 4:49 10:10 11 6:40 4:48 10:08 12 6:41 4:47 10:06 13 6:42 4:46 10:04 14 6:43 4:45 10:02 15 6:44 4:45 10:01 16 6:45 4:44 9:59 17 6:47 4:43 9:56 18 6:48 4:42 9:54 19 6:49 4:42 9:53 20 6:50 4:41 9:51 21 6:51 4:40 9:49 22 6:52 4:40 9:48 23 6:53 4:39 9:46 24 6:54 4:39 9:45 25 6:55 4:38 9:43 26 6:56 4:38 9:42 27 6:58 4:37 9:39 28 6:59 4:37 9:38 29 7:00 4:37 9:37 30 7:01 4:36 9:35Back to top
December
Sunrise Sunset Length-of-Day 1 7:02 4:36 9:34 2 7:03 4:36 9:33 3 7:04 4:36 9:32 4 7:05 4:36 9:31 5 7:06 4:35 9:29 6 7:06 4:35 9:29 7 7:07 4:35 9:28 8 7:08 4:35 9:27 9 7:09 4:35 9:26 10 7:10 4:35 9:25 11 7:11 4:36 9:25 12 7:12 4:36 9:24 13 7:12 4:36 9:24 14 7:13 4:36 9:23 15 7:14 4:36 9:22 16 7:14 4:37 9:23 17 7:15 4:37 9:22 18 7:16 4:37 9:21 19 7:16 4:38 9:22 20 7:17 4:38 9:21 21 7:17 4:39 9:22 22 7:18 4:39 9:21 23 7:18 4:40 9:22 24 7:19 4:40 9:21 25 7:19 4:41 9:22 26 7:20 4:41 9:21 27 7:20 4:42 9:22 28 7:20 4:43 9:23 29 7:21 4:44 9:23 30 7:21 4:44 9:23 31 7:21 4:45 9:24Back to top
Duration of Civil Twilight at 40N
Day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1 30 29 27 27 29 32 33 30 28 27 28 30 9 30 28 27 28 30 33 32 30 27 27 29 30 17 30 28 27 28 31 33 32 29 27 27 29 31 25 29 27 27 29 32 33 31 28 27 28 30 31