Camp Creek
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camp Creek clear sky chart from 2005-11-06 to 2025-03-27.

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	13% 9% 4 9% 5% 5% 5% 4 6% 7% 33%	109579
	Night	12% 9% 4 9% 6% 5% 5% 4 5% 7% 36%	109777
Transparency	Day	45% 6% 11% 22% 13% 3	113268
	Night	44% 6% 11% 23% 13% 3	114227
Seeing	Day	22% 13% 23% 21% 14% 7%	15609
	Night	19% 12% 21% 29% 17% 2	25788

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	13% 14% 6% 14% 7% 4 3 3 4 6% 26%	4056
	11th to 20th	Day	11% 12% 8% 17% 6% 6% 3 2 3 3 29%	4060
	21st to end	Day	13% 13% 5% 9% 4 3 3 3 5% 6% 36%	4466
February	1st to 10th	Day	13% 11% 4 12% 5% 5% 5% 4 5% 6% 30%	1800
	11th to 20th	Day	16% 11% 4 11% 6% 5% 4 3 6% 6% 27%	1871
	21st to end	Day	16% 11% 5% 11% 5% 4 4 3 4 6% 31%	1660
March	1st to 10th	Day	21% 12% 4 7% 5% 4 4 3 4 6% 29%	3545
	11th to 20th	Day	11% 9% 3 7% 4 4 4 4 6% 6% 42%	3590
	21st to end	Day	15% 10% 3 7% 6% 4 5% 4 6% 6% 35%	3881
April	1st to 10th	Day	12% 11% 4 6% 5% 5% 5% 4 6% 7% 36%	2104
	11th to 20th	Day	13% 9% 3 7% 5% 5% 4 3 5% 6% 40%	2291
	21st to end	Day	17% 8% 3 6% 5% 4 5% 4 5% 6% 36%	2470
May	1st to 10th	Day	17% 10% 3 10% 6% 5% 6% 5% 7% 6% 25%	4082
	11th to 20th	Day	19% 9% 3 8% 6% 6% 5% 5% 7% 6% 27%	4081
	21st to end	Day	10% 6% 2 7% 5% 6% 7% 6% 7% 10% 34%	4476
June	1st to 10th	Day	12% 5% 3 8% 6% 6% 5% 5% 6% 9% 35%	2470
	11th to 20th	Day	9% 5% 2 7% 5% 6% 7% 6% 7% 10% 35%	2470
	21st to end	Day	9% 6% 2 7% 5% 6% 6% 6% 7% 8% 37%	2470
July	1st to 10th	Day	7% 5% 2 7% 6% 6% 7% 5% 8% 9% 38%	4120
	11th to 20th	Day	9% 6% 3 7% 5% 5% 6% 5% 7% 11% 36%	4120
	21st to end	Day	14% 9% 4 11% 8% 7% 6% 5% 6% 8% 23%	4466
August	1st to 10th	Day	10% 7% 3 8% 7% 7% 7% 6% 8% 11% 27%	4104
	11th to 20th	Day	9% 6% 3 8% 6% 7% 7% 6% 9% 10% 28%	4044
	21st to end	Day	5% 4 2 6% 4 5% 6% 5% 6% 11% 47%	4322
September	1st to 10th	Day	11% 6% 3 7% 5% 5% 5% 4 5% 6% 43%	2147
	11th to 20th	Day	13% 8% 3 7% 5% 6% 5% 3 5% 8% 36%	2090
	21st to end	Day	19% 8% 3 7% 4 4 5% 4 5% 7% 33%	2090
October	1st to 10th	Day	14% 7% 2 7% 4 3 4 3 6% 7% 43%	1967
	11th to 20th	Day	14% 8% 3 7% 3 3 4 4 4 6% 43%	1900
	21st to end	Day	14% 11% 3 7% 4 4 3 3 3 6% 42%	2090
November	1st to 10th	Day	10% 7% 3 7% 4 4 4 4 6% 7% 46%	1907
	11th to 20th	Day	12% 10% 4 8% 4 4 5% 3 5% 7% 38%	1800
	21st to end	Day	12% 11% 4 7% 5% 4 5% 4 5% 6% 38%	1800
December	1st to 10th	Day	12% 11% 5% 11% 5% 4 4 3 5% 6% 33%	2930
	11th to 20th	Day	18% 14% 5% 10% 5% 4 4 4 5% 6% 26%	3373
	21st to end	Day	14% 12% 6% 11% 6% 6% 6% 5% 6% 6% 23%	4466
January	1st to 10th	Night	10% 13% 7% 17% 10% 4 3 3 5% 4 23%	5889
	11th to 20th	Night	14% 10% 5% 14% 8% 6% 4 3 4 5% 29%	5900
	21st to end	Night	13% 11% 3 8% 5% 6% 4 4 5% 6% 35%	6490
February	1st to 10th	Night	13% 11% 5% 10% 5% 5% 4 5% 5% 7% 30%	2600
	11th to 20th	Night	18% 11% 4 12% 7% 5% 5% 4 4 5% 27%	2410
	21st to end	Night	13% 11% 5% 12% 6% 5% 4 4 5% 5% 29%	1970
March	1st to 10th	Night	20% 14% 3 6% 4 5% 4 3 3 6% 32%	3528
	11th to 20th	Night	12% 9% 3 7% 5% 4 4 4 5% 6% 41%	3590
	21st to end	Night	13% 8% 2 6% 4 4 5% 4 6% 7% 41%	3890
April	1st to 10th	Night	10% 11% 3 7% 5% 5% 5% 4 5% 8% 36%	2076
	11th to 20th	Night	11% 9% 2 6% 5% 4 4 4 7% 7% 42%	1853
	21st to end	Night	13% 7% 3 7% 6% 5% 5% 3 6% 7% 38%	1710
May	1st to 10th	Night	17% 12% 4 8% 5% 4 5% 4 6% 6% 28%	2813
	11th to 20th	Night	19% 11% 3 8% 5% 4 4 3 4 7% 33%	2812
	21st to end	Night	10% 7% 3 8% 5% 4 6% 4 6% 9% 38%	3079
June	1st to 10th	Night	10% 5% 2 6% 5% 5% 5% 4 7% 9% 41%	1710
	11th to 20th	Night	8% 5% 2 7% 5% 5% 4 4 8% 10% 42%	1710
	21st to end	Night	8% 6% 2 5% 5% 5% 5% 4 8% 11% 41%	1710
July	1st to 10th	Night	5% 5% 2 7% 5% 6% 6% 5% 8% 11% 40%	2840
	11th to 20th	Night	7% 4 2 7% 4 3 5% 4 7% 10% 46%	2840
	21st to end	Night	9% 10% 3 10% 6% 6% 6% 6% 7% 9% 28%	3087
August	1st to 10th	Night	11% 7% 3 9% 5% 6% 5% 5% 7% 8% 34%	2825
	11th to 20th	Night	8% 7% 3 8% 5% 6% 6% 5% 7% 7% 38%	2785
	21st to end	Night	5% 3 1 4 4 4 4 3 7% 10% 54%	3302
September	1st to 10th	Night	9% 7% 2 7% 5% 4 5% 4 5% 6% 47%	2028
	11th to 20th	Night	13% 7% 3 6% 3 3 5% 3 4 7% 46%	2090
	21st to end	Night	13% 9% 3 6% 4 3 4 4 5% 7% 41%	2090
October	1st to 10th	Night	13% 6% 2 5% 5% 3 4 4 4 6% 48%	2213
	11th to 20th	Night	11% 9% 3 6% 5% 5% 4 3 4 6% 45%	2280
	21st to end	Night	11% 9% 3 7% 4 4 4 3 5% 5% 46%	2508
November	1st to 10th	Night	10% 9% 3 7% 4 4 4 4 4 5% 46%	2387
	11th to 20th	Night	11% 10% 3 7% 5% 4 5% 4 5% 6% 40%	2600
	21st to end	Night	11% 10% 3 8% 5% 4 4 3 5% 6% 40%	2600
December	1st to 10th	Night	11% 8% 4 9% 7% 5% 5% 4 6% 7% 33%	4250
	11th to 20th	Night	16% 11% 7% 13% 5% 5% 4 3 5% 6% 25%	4822
	21st to end	Night	14% 10% 6% 12% 7% 6% 6% 5% 5% 7% 22%	6490

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	57% 3 6% 20% 13% 1	4057
	11th to 20th	Day	58% 3 5% 14% 16% 3	4060
	21st to end	Day	49% 3 8% 24% 14% 2	4466
February	1st to 10th	Day	53% 5% 9% 21% 13% 1	1800
	11th to 20th	Day	56% 4 8% 18% 12% 2	1880
	21st to end	Day	53% 4 8% 18% 14% 4	1660
March	1st to 10th	Day	52% 6% 8% 20% 12% 2	3545
	11th to 20th	Day	41% 4 9% 24% 19% 3	3590
	21st to end	Day	47% 5% 10% 24% 12% 2	3881
April	1st to 10th	Day	45% 4 11% 23% 14% 3	2104
	11th to 20th	Day	43% 4 10% 24% 16% 3	2291
	21st to end	Day	47% 5% 12% 23% 12% 2	2470
May	1st to 10th	Day	55% 6% 11% 18% 9% 1	4120
	11th to 20th	Day	53% 7% 11% 22% 7% 1	4085
	21st to end	Day	40% 8% 16% 21% 11% 3	4489
June	1st to 10th	Day	43% 7% 14% 22% 13%	2470
	11th to 20th	Day	39% 9% 16% 20% 14% 1	2470
	21st to end	Day	40% 8% 15% 21% 14% 2	2470
July	1st to 10th	Day	38% 10% 20% 20% 9% 3	4055
	11th to 20th	Day	38% 8% 17% 27% 8% 1	4051
	21st to end	Day	56% 7% 11% 17% 7%	4324
August	1st to 10th	Day	44% 11% 18% 20% 6%	4091
	11th to 20th	Day	41% 10% 15% 24% 10%	4083
	21st to end	Day	29% 8% 18% 31% 13% 1	4322
September	1st to 10th	Day	39% 7% 13% 21% 16% 4	2147
	11th to 20th	Day	46% 5% 9% 22% 17% 2	2090
	21st to end	Day	49% 6% 10% 19% 14% 2	2090
October	1st to 10th	Day	30% 6% 9% 20% 28% 6%	3266
	11th to 20th	Day	31% 3 9% 25% 17% 15%	3140
	21st to end	Day	31% 3 8% 30% 14% 13%	3428
November	1st to 10th	Day	36% 4 9% 24% 23% 3	1907
	11th to 20th	Day	44% 4 8% 22% 19% 4	1800
	21st to end	Day	44% 3 11% 23% 16% 2	1800
December	1st to 10th	Day	50% 5% 8% 21% 16% 1	2930
	11th to 20th	Day	57% 4 9% 16% 14% 1	3370
	21st to end	Day	57% 5% 10% 20% 7% 1	4466
January	1st to 10th	Night	60% 5% 7% 18% 10% 1	5889
	11th to 20th	Night	54% 4 6% 17% 17% 4	5900
	21st to end	Night	47% 4 9% 24% 14% 1	6490
February	1st to 10th	Night	50% 3 14% 19% 13% 1	2600
	11th to 20th	Night	59% 3 8% 17% 11% 3	2412
	21st to end	Night	54% 4 10% 18% 10% 5%	1970
March	1st to 10th	Night	54% 5% 6% 23% 11% 2	3528
	11th to 20th	Night	42% 4 7% 28% 17% 2	3590
	21st to end	Night	40% 5% 13% 24% 17% 2	3890
April	1st to 10th	Night	44% 5% 12% 22% 14% 3	2076
	11th to 20th	Night	39% 4 12% 23% 17% 4	1853
	21st to end	Night	43% 5% 14% 25% 12% 1	1710
May	1st to 10th	Night	52% 5% 15% 19% 8% 1	2840
	11th to 20th	Night	50% 7% 13% 25% 5% 1	2813
	21st to end	Night	39% 8% 17% 25% 8% 3	3087
June	1st to 10th	Night	35% 10% 18% 23% 14% 1	1710
	11th to 20th	Night	35% 8% 20% 22% 13% 2	1710
	21st to end	Night	34% 8% 16% 25% 14% 2	1710
July	1st to 10th	Night	33% 12% 22% 19% 11% 2	2795
	11th to 20th	Night	29% 8% 21% 33% 8% 2	2786
	21st to end	Night	46% 12% 14% 21% 7%	2988
August	1st to 10th	Night	44% 9% 19% 22% 6%	2814
	11th to 20th	Night	38% 9% 15% 28% 10%	2812
	21st to end	Night	25% 7% 15% 37% 15% 1	3302
September	1st to 10th	Night	37% 7% 14% 21% 15% 5%	2028
	11th to 20th	Night	38% 6% 10% 25% 19% 1	2090
	21st to end	Night	43% 5% 11% 25% 15% 1	2090
October	1st to 10th	Night	31% 5% 8% 24% 28% 4	3694
	11th to 20th	Night	30% 5% 9% 23% 20% 13%	3779
	21st to end	Night	24% 3 9% 32% 20% 12%	4120
November	1st to 10th	Night	38% 4 9% 22% 23% 4	2387
	11th to 20th	Night	42% 4 9% 20% 20% 5%	2600
	21st to end	Night	44% 3 10% 23% 17% 4	2600
December	1st to 10th	Night	44% 7% 11% 25% 11% 1	4250
	11th to 20th	Night	59% 5% 9% 18% 9% 1	4824
	21st to end	Night	56% 6% 11% 18% 9%	6490

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	41% 26% 20% 8% 3 1	300
	11th to 20th	Day	42% 20% 28% 9% 1	300
	21st to end	Day	38% 23% 25% 11% 3	330
February	1st to 10th	Day	31% 27% 26% 14% 2	300
	11th to 20th	Day	49% 22% 20% 8% 1	300
	21st to end	Day	38% 25% 29% 7% 2	259
March	1st to 10th	Day	31% 21% 23% 18% 6% 1	500
	11th to 20th	Day	30% 24% 24% 17% 4 1	500
	21st to end	Day	30% 21% 27% 15% 6%	530
April	1st to 10th	Day	28% 21% 24% 17% 9% 1	460
	11th to 20th	Day	22% 17% 29% 19% 10% 2	452
	21st to end	Day	28% 14% 28% 16% 11% 2	460
May	1st to 10th	Day	27% 15% 27% 18% 9% 5%	463
	11th to 20th	Day	22% 9% 29% 20% 14% 6%	487
	21st to end	Day	16% 8% 21% 25% 17% 12%	529
June	1st to 10th	Day	13% 7% 27% 25% 19% 10%	490
	11th to 20th	Day	9% 9% 25% 28% 18% 11%	490
	21st to end	Day	11% 10% 24% 28% 16% 10%	490
July	1st to 10th	Day	13% 5% 19% 26% 22% 16%	485
	11th to 20th	Day	7% 3 19% 33% 22% 14%	484
	21st to end	Day	13% 5% 19% 25% 25% 13%	532
August	1st to 10th	Day	11% 6% 21% 24% 23% 15%	486
	11th to 20th	Day	11% 4 20% 24% 24% 16%	479
	21st to end	Day	9% 3 16% 27% 25% 19%	539
September	1st to 10th	Day	11% 5% 17% 28% 26% 13%	490
	11th to 20th	Day	15% 5% 12% 28% 28% 12%	490
	21st to end	Day	24% 9% 17% 29% 16% 4	490
October	1st to 10th	Day	20% 5% 20% 26% 23% 6%	490
	11th to 20th	Day	17% 17% 21% 23% 19% 4	490
	21st to end	Day	22% 12% 26% 21% 15% 3	539
November	1st to 10th	Day	18% 13% 27% 26% 12% 3	445
	11th to 20th	Day	28% 16% 23% 25% 6% 2	300
	21st to end	Day	28% 19% 29% 19% 4 1	300
December	1st to 10th	Day	37% 20% 26% 13% 4	300
	11th to 20th	Day	31% 20% 27% 13% 7% 1	300
	21st to end	Day	28% 20% 26% 18% 5% 2	330
January	1st to 10th	Night	27% 25% 26% 20% 3	800
	11th to 20th	Night	32% 19% 26% 21% 2	800
	21st to end	Night	25% 23% 30% 19% 2	880
February	1st to 10th	Night	27% 19% 27% 25% 2	800
	11th to 20th	Night	32% 24% 27% 16% 1	783
	21st to end	Night	26% 21% 34% 18% 1	660
March	1st to 10th	Night	25% 16% 31% 24% 3	800
	11th to 20th	Night	27% 18% 27% 22% 7%	800
	21st to end	Night	21% 17% 31% 24% 7%	863
April	1st to 10th	Night	21% 18% 27% 28% 6%	760
	11th to 20th	Night	19% 14% 27% 29% 11% 1	729
	21st to end	Night	17% 13% 25% 36% 9% 1	570
May	1st to 10th	Night	17% 10% 24% 33% 14% 1	570
	11th to 20th	Night	17% 7% 20% 35% 21% 1	561
	21st to end	Night	13% 4 14% 34% 31% 5%	617
June	1st to 10th	Night	10% 3 16% 40% 27% 4	570
	11th to 20th	Night	9% 3 15% 35% 34% 5%	570
	21st to end	Night	8% 4 14% 41% 30% 3	570
July	1st to 10th	Night	8% 2 12% 35% 39% 4	555
	11th to 20th	Night	7% 2 8% 35% 43% 5%	552
	21st to end	Night	7% 2 9% 39% 38% 5%	624
August	1st to 10th	Night	11% 1 8% 37% 38% 5%	567
	11th to 20th	Night	12% 2 10% 34% 38% 4	564
	21st to end	Night	10% 2 7% 34% 40% 7%	727
September	1st to 10th	Night	11% 4 9% 33% 37% 6%	760
	11th to 20th	Night	15% 3 10% 33% 34% 4	760
	21st to end	Night	18% 6% 14% 35% 26% 1	760
October	1st to 10th	Night	16% 7% 18% 30% 25% 4	760
	11th to 20th	Night	16% 12% 23% 31% 16% 1	760
	21st to end	Night	19% 12% 20% 36% 12% 2	836
November	1st to 10th	Night	17% 9% 24% 33% 16% 2	780
	11th to 20th	Night	21% 14% 23% 30% 12% 1	800
	21st to end	Night	20% 14% 24% 32% 9% 1	800
December	1st to 10th	Night	26% 18% 28% 23% 5%	800
	11th to 20th	Night	22% 20% 27% 26% 5%	800
	21st to end	Night	26% 15% 25% 30% 4	880

Page generated at 2025-03-24 09:04:29. Version ac07

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