Camp Crooked Creek
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camp Crooked Creek clear sky chart from 2005-11-06 to 2025-12-03.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	14% 8% 3 7% 4 4 5% 4 6% 8% 38%	126901
	Night	15% 9% 3 7% 4 4 4 3 5% 7% 39%	123878
Transparency	Day	43% 6% 11% 23% 16% 2	130556
	Night	43% 5% 10% 22% 17% 3	128294
Seeing	Day	17% 11% 25% 23% 16% 7%	16737
	Night	18% 9% 25% 29% 17% 2	26436

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	15% 14% 7% 8% 4 4 4 4 6% 6% 29%	3617
	11th to 20th	Day	15% 12% 5% 14% 4 4 4 2 4 4 33%	3809
	21st to end	Day	21% 12% 5% 6% 5% 4 3 3 4 5% 32%	4540
February	1st to 10th	Day	19% 12% 4 9% 4 4 3 3 3 6% 34%	2000
	11th to 20th	Day	19% 10% 4 8% 5% 4 4 3 5% 6% 34%	1948
	21st to end	Day	18% 11% 4 7% 5% 3 4 4 6% 5% 32%	1650
March	1st to 10th	Day	20% 13% 4 6% 3 3 3 3 4 5% 36%	4480
	11th to 20th	Day	13% 9% 3 6% 4 4 3 3 5% 7% 43%	4883
	21st to end	Day	15% 8% 3 8% 5% 4 5% 3 6% 7% 37%	5586
April	1st to 10th	Day	14% 7% 2 6% 5% 4 5% 3 6% 7% 40%	2400
	11th to 20th	Day	15% 9% 2 7% 4 4 4 3 5% 6% 40%	2374
	21st to end	Day	17% 8% 2 6% 6% 5% 4 3 6% 6% 37%	2558
May	1st to 10th	Day	19% 9% 3 8% 5% 6% 6% 4 7% 7% 26%	5862
	11th to 20th	Day	17% 8% 3 8% 4 5% 4 4 6% 7% 33%	5861
	21st to end	Day	13% 7% 3 7% 5% 6% 5% 5% 8% 10% 33%	6433
June	1st to 10th	Day	10% 5% 2 6% 5% 5% 6% 5% 6% 7% 43%	2630
	11th to 20th	Day	6% 4 2 6% 5% 6% 6% 4 7% 10% 43%	2800
	21st to end	Day	6% 6% 2 5% 5% 5% 6% 4 7% 10% 44%	2800
July	1st to 10th	Day	9% 6% 2 7% 4 5% 5% 5% 6% 10% 41%	6360
	11th to 20th	Day	8% 6% 3 7% 5% 6% 6% 5% 9% 11% 37%	6230
	21st to end	Day	10% 8% 3 9% 6% 6% 7% 5% 8% 10% 28%	6424
August	1st to 10th	Day	6% 5% 2 5% 4 4 5% 4 7% 11% 47%	4234
	11th to 20th	Day	7% 5% 2 6% 5% 5% 6% 5% 8% 11% 39%	3947
	21st to end	Day	5% 3 1 5% 4 4 4 4 6% 8% 56%	4312
September	1st to 10th	Day	13% 5% 3 6% 4 4 4 3 5% 7% 44%	2326
	11th to 20th	Day	11% 6% 2 5% 3 4 4 4 6% 9% 47%	2200
	21st to end	Day	14% 6% 3 5% 4 4 4 3 5% 7% 47%	2200
October	1st to 10th	Day	10% 4 2 4 4 3 3 3 5% 7% 55%	2200
	11th to 20th	Day	13% 5% 2 5% 3 3 4 3 5% 6% 51%	2116
	21st to end	Day	19% 7% 2 6% 3 3 3 3 5% 5% 44%	1988
November	1st to 10th	Day	12% 6% 2 5% 4 4 4 3 4 7% 51%	1852
	11th to 20th	Day	15% 10% 2 6% 4 3 3 3 5% 6% 43%	1890
	21st to end	Day	18% 10% 3 7% 4 3 4 3 4 5% 39%	1890
December	1st to 10th	Day	18% 11% 2 7% 4 3 3 3 4 5% 41%	2948
	11th to 20th	Day	17% 12% 5% 10% 6% 4 4 3 4 5% 30%	3373
	21st to end	Day	22% 16% 5% 8% 4 4 4 3 4 6% 23%	4180
January	1st to 10th	Night	16% 16% 6% 11% 5% 3 4 3 4 5% 27%	6348
	11th to 20th	Night	17% 14% 6% 10% 5% 5% 4 2 3 3 30%	6156
	21st to end	Night	20% 11% 3 6% 4 3 3 2 4 5% 38%	6399
February	1st to 10th	Night	22% 13% 4 8% 4 3 4 3 5% 6% 28%	2400
	11th to 20th	Night	21% 10% 4 9% 5% 3 4 3 3 5% 34%	2338
	21st to end	Night	22% 10% 4 7% 4 4 4 3 4 5% 33%	1980
March	1st to 10th	Night	21% 14% 2 6% 5% 4 4 2 4 5% 35%	5373
	11th to 20th	Night	13% 8% 3 6% 4 4 4 3 4 5% 47%	5076
	21st to end	Night	15% 9% 3 8% 5% 5% 5% 4 5% 6% 35%	5386
April	1st to 10th	Night	13% 6% 2 7% 5% 4 5% 4 5% 6% 43%	2000
	11th to 20th	Night	15% 9% 3 6% 4 3 3 3 5% 6% 42%	1975
	21st to end	Night	16% 8% 2 6% 6% 4 5% 4 5% 7% 38%	1840
May	1st to 10th	Night	19% 11% 3 8% 5% 4 5% 4 6% 9% 27%	4033
	11th to 20th	Night	15% 8% 3 8% 5% 5% 5% 4 6% 7% 32%	4032
	21st to end	Night	11% 7% 3 7% 5% 5% 5% 5% 8% 9% 36%	4421
June	1st to 10th	Night	10% 5% 2 5% 4 3 4 4 6% 9% 48%	1764
	11th to 20th	Night	6% 4 2 5% 4 4 5% 5% 7% 9% 49%	1600
	21st to end	Night	4 4 2 4 4 5% 5% 4 7% 12% 48%	1600
July	1st to 10th	Night	7% 5% 2 7% 5% 5% 5% 4 5% 9% 47%	3618
	11th to 20th	Night	6% 5% 2 6% 4 5% 5% 5% 8% 11% 43%	3739
	21st to end	Night	8% 8% 3 9% 6% 6% 6% 5% 7% 10% 32%	4427
August	1st to 10th	Night	6% 4 2 5% 4 4 4 4 6% 9% 53%	2915
	11th to 20th	Night	6% 4 2 6% 4 5% 5% 5% 7% 10% 46%	3097
	21st to end	Night	3 3 1 3 3 3 3 3 6% 9% 63%	3586
September	1st to 10th	Night	10% 5% 2 5% 4 4 4 3 6% 6% 50%	2052
	11th to 20th	Night	8% 5% 2 5% 4 4 4 4 5% 7% 51%	2200
	21st to end	Night	12% 5% 2 5% 4 4 3 4 4 5% 52%	2200
October	1st to 10th	Night	9% 4 2 5% 3 2 3 3 4 7% 59%	2200
	11th to 20th	Night	13% 5% 2 4 4 4 3 3 4 6% 51%	2282
	21st to end	Night	17% 7% 2 5% 3 3 3 3 4 5% 46%	2850
November	1st to 10th	Night	13% 7% 2 5% 3 3 3 4 5% 5% 50%	2666
	11th to 20th	Night	14% 8% 3 7% 4 4 4 3 4 7% 45%	2730
	21st to end	Night	18% 10% 4 5% 4 3 3 3 4 5% 39%	2730
December	1st to 10th	Night	19% 11% 3 7% 4 4 3 2 4 4 38%	4277
	11th to 20th	Night	21% 11% 4 7% 4 3 3 3 4 6% 35%	4822
	21st to end	Night	23% 16% 5% 9% 5% 5% 5% 3 4 4 21%	6766

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	55% 4 10% 23% 8% 1	3618
	11th to 20th	Day	56% 3 6% 19% 14% 3	3809
	21st to end	Day	54% 3 9% 19% 11% 3	4540
February	1st to 10th	Day	54% 3 8% 23% 11% 2	2000
	11th to 20th	Day	53% 4 8% 21% 11% 3	1958
	21st to end	Day	52% 4 8% 20% 12% 3	1650
March	1st to 10th	Day	51% 3 5% 18% 17% 5%	4480
	11th to 20th	Day	40% 4 9% 26% 19% 2	4883
	21st to end	Day	46% 5% 11% 26% 12% 1	5588
April	1st to 10th	Day	42% 6% 12% 23% 16% 2	2400
	11th to 20th	Day	45% 5% 9% 22% 17% 3	2374
	21st to end	Day	46% 5% 10% 25% 11% 2	2558
May	1st to 10th	Day	54% 8% 12% 16% 10%	5897
	11th to 20th	Day	49% 7% 12% 20% 12%	5865
	21st to end	Day	43% 8% 14% 17% 16% 2	6447
June	1st to 10th	Day	39% 7% 9% 24% 18% 3	2630
	11th to 20th	Day	34% 9% 14% 24% 18% 2	2800
	21st to end	Day	33% 10% 13% 21% 18% 5%	2800
July	1st to 10th	Day	37% 7% 13% 23% 19% 1	6291
	11th to 20th	Day	37% 9% 16% 26% 9% 2	6155
	21st to end	Day	49% 9% 14% 19% 9% 1	6240
August	1st to 10th	Day	28% 8% 15% 34% 15% 1	4221
	11th to 20th	Day	35% 8% 12% 28% 15% 1	3986
	21st to end	Day	25% 6% 10% 39% 17% 3	4311
September	1st to 10th	Day	38% 6% 11% 20% 20% 4	2326
	11th to 20th	Day	33% 6% 11% 25% 22% 3	2200
	21st to end	Day	38% 4 8% 23% 23% 4	2200
October	1st to 10th	Day	20% 4 6% 27% 41% 3	3590
	11th to 20th	Day	24% 3 10% 28% 32% 3	3421
	21st to end	Day	32% 4 7% 30% 21% 7%	3188
November	1st to 10th	Day	34% 5% 8% 28% 21% 4	1852
	11th to 20th	Day	42% 3 8% 24% 18% 4	1890
	21st to end	Day	47% 3 8% 22% 18% 1	1890
December	1st to 10th	Day	48% 2 8% 24% 17% 1	2948
	11th to 20th	Day	58% 4 8% 18% 11% 2	3370
	21st to end	Day	62% 4 11% 16% 6%	4180
January	1st to 10th	Night	59% 4 8% 20% 9% 1	6348
	11th to 20th	Night	59% 4 5% 18% 12% 3	6156
	21st to end	Night	50% 3 8% 22% 16% 2	6399
February	1st to 10th	Night	57% 5% 11% 17% 9% 1	2400
	11th to 20th	Night	54% 3 7% 21% 14% 2	2339
	21st to end	Night	55% 4 9% 16% 13% 3	1980
March	1st to 10th	Night	53% 3 5% 21% 13% 4	5373
	11th to 20th	Night	38% 5% 8% 24% 21% 4	5076
	21st to end	Night	49% 4 9% 24% 13% 1	5386
April	1st to 10th	Night	40% 6% 11% 22% 18% 3	2000
	11th to 20th	Night	43% 3 9% 20% 19% 6%	1975
	21st to end	Night	45% 6% 9% 23% 14% 2	1840
May	1st to 10th	Night	54% 7% 10% 20% 8% 1	4060
	11th to 20th	Night	50% 8% 11% 22% 9% 1	4033
	21st to end	Night	40% 9% 15% 21% 14% 2	4429
June	1st to 10th	Night	31% 6% 13% 26% 19% 4	1764
	11th to 20th	Night	30% 7% 14% 23% 21% 4	1600
	21st to end	Night	27% 8% 18% 23% 19% 6%	1600
July	1st to 10th	Night	34% 7% 12% 27% 18% 2	3580
	11th to 20th	Night	32% 10% 17% 27% 11% 2	3694
	21st to end	Night	44% 10% 15% 19% 12% 1	4297
August	1st to 10th	Night	26% 8% 14% 36% 15% 1	2904
	11th to 20th	Night	30% 8% 14% 29% 17% 2	3124
	21st to end	Night	18% 6% 14% 34% 25% 4	3586
September	1st to 10th	Night	32% 7% 11% 22% 22% 6%	2052
	11th to 20th	Night	31% 6% 10% 25% 25% 4	2200
	21st to end	Night	33% 4 8% 24% 25% 5%	2200
October	1st to 10th	Night	20% 3 6% 19% 48% 4	3590
	11th to 20th	Night	24% 3 6% 25% 35% 6%	3716
	21st to end	Night	31% 3 7% 21% 31% 7%	4600
November	1st to 10th	Night	36% 3 8% 25% 23% 4	2666
	11th to 20th	Night	41% 4 7% 22% 20% 6%	2730
	21st to end	Night	47% 4 8% 23% 17% 2	2730
December	1st to 10th	Night	51% 3 9% 21% 15% 1	4277
	11th to 20th	Night	51% 3 10% 21% 14% 1	4824
	21st to end	Night	66% 4 8% 15% 6%	6766

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	26% 18% 31% 18% 5% 1	300
	11th to 20th	Day	31% 25% 28% 13% 3	300
	21st to end	Day	24% 26% 34% 13% 3	330
February	1st to 10th	Day	26% 21% 41% 10% 1 1	300
	11th to 20th	Day	29% 27% 32% 8% 2 1	300
	21st to end	Day	31% 19% 37% 11% 2	249
March	1st to 10th	Day	28% 21% 32% 16% 3	300
	11th to 20th	Day	24% 18% 38% 13% 5% 1	455
	21st to end	Day	28% 20% 31% 16% 4 1	550
April	1st to 10th	Day	22% 17% 29% 23% 8% 1	500
	11th to 20th	Day	21% 20% 27% 20% 10% 3	492
	21st to end	Day	22% 14% 34% 19% 8% 3	500
May	1st to 10th	Day	19% 17% 30% 24% 6% 4	503
	11th to 20th	Day	18% 10% 28% 24% 14% 5%	527
	21st to end	Day	13% 8% 26% 26% 17% 10%	573
June	1st to 10th	Day	11% 5% 26% 26% 23% 9%	560
	11th to 20th	Day	6% 6% 21% 35% 23% 10%	730
	21st to end	Day	8% 5% 26% 26% 23% 12%	730
July	1st to 10th	Day	12% 4 16% 25% 25% 18%	721
	11th to 20th	Day	9% 4 18% 34% 22% 14%	666
	21st to end	Day	11% 3 13% 30% 29% 13%	576
August	1st to 10th	Day	10% 3 16% 26% 28% 17%	526
	11th to 20th	Day	11% 5% 15% 28% 30% 11%	519
	21st to end	Day	8% 3 11% 29% 32% 17%	583
September	1st to 10th	Day	12% 5% 16% 25% 31% 11%	530
	11th to 20th	Day	12% 3 13% 23% 32% 16%	530
	21st to end	Day	16% 8% 20% 24% 23% 10%	530
October	1st to 10th	Day	12% 4 19% 32% 24% 8%	530
	11th to 20th	Day	14% 12% 29% 26% 15% 4	530
	21st to end	Day	25% 15% 35% 16% 8% 1	371
November	1st to 10th	Day	18% 11% 34% 25% 8% 3	330
	11th to 20th	Day	25% 18% 30% 22% 4 2	330
	21st to end	Day	26% 14% 35% 18% 7% 1	330
December	1st to 10th	Day	25% 19% 31% 19% 6% 1	306
	11th to 20th	Day	25% 15% 38% 13% 8% 1	300
	21st to end	Day	32% 21% 27% 17% 3	330
January	1st to 10th	Night	21% 18% 31% 26% 4	1000
	11th to 20th	Night	28% 15% 33% 19% 4	913
	21st to end	Night	24% 14% 38% 23% 2	880
February	1st to 10th	Night	29% 13% 34% 22% 2	800
	11th to 20th	Night	28% 16% 35% 19% 2	783
	21st to end	Night	27% 16% 36% 20% 2	660
March	1st to 10th	Night	23% 16% 31% 24% 5%	800
	11th to 20th	Night	24% 12% 34% 24% 6%	800
	21st to end	Night	24% 12% 29% 28% 6%	850
April	1st to 10th	Night	16% 14% 32% 30% 9%	600
	11th to 20th	Night	20% 11% 28% 28% 11% 1	593
	21st to end	Night	18% 10% 33% 30% 9% 1	600
May	1st to 10th	Night	22% 7% 27% 29% 15% 1	600
	11th to 20th	Night	15% 7% 18% 39% 17% 4	591
	21st to end	Night	9% 3 19% 37% 26% 5%	650
June	1st to 10th	Night	11% 3 19% 37% 27% 3	600
	11th to 20th	Night	8% 3 15% 42% 30% 3	600
	21st to end	Night	5% 2 17% 43% 30% 4	600
July	1st to 10th	Night	12% 2 10% 27% 40% 9%	585
	11th to 20th	Night	7% 2 10% 34% 40% 6%	582
	21st to end	Night	10% 3 10% 33% 37% 7%	657
August	1st to 10th	Night	8% 2 10% 30% 44% 6%	597
	11th to 20th	Night	6% 3 9% 40% 36% 6%	594
	21st to end	Night	7% 1 7% 35% 46% 4	660
September	1st to 10th	Night	12% 2 10% 35% 36% 5%	652
	11th to 20th	Night	10% 3 13% 30% 39% 4	800
	21st to end	Night	13% 5% 19% 34% 27% 3	800
October	1st to 10th	Night	11% 4 17% 35% 30% 4	800
	11th to 20th	Night	15% 7% 26% 33% 17% 1	800
	21st to end	Night	20% 8% 33% 26% 12% 1	880
November	1st to 10th	Night	15% 9% 28% 32% 16% 1	820
	11th to 20th	Night	18% 12% 32% 28% 10%	840
	21st to end	Night	24% 12% 25% 28% 11%	840
December	1st to 10th	Night	27% 11% 29% 28% 5%	809
	11th to 20th	Night	26% 10% 32% 25% 7%	800
	21st to end	Night	30% 13% 30% 24% 4	1000

Page generated at 2025-11-30 01:00:53. Version ac07

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