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	3 2 1 3 2 3 3 3 4 6% 69%	113679
	Night	4 3 1 3 3 3 3 3 4 6% 68%	114546
Transparency	Day	17% 2 5% 13% 26% 37%	113446
	Night	18% 2 5% 12% 25% 38%	114369
Seeing	Day	5% 6% 23% 36% 24% 6%	15438
	Night	5% 2 16% 42% 32% 4	25687

By Month

Percentage Cloud Cover SW (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	5% 3 2 5% 3 3 3 2 4 4 66%	4098
	11th to 20th	Day	3 2 1 3 3 3 3 2 3 4 73%	4100
	21st to end	Day	9% 5% 2 4 4 3 4 3 4 6% 58%	4510
February	1st to 10th	Day	5% 5% 1 3 2 3 3 4 4 6% 63%	1865
	11th to 20th	Day	8% 4 2 5% 3 3 4 3 5% 7% 58%	1950
	21st to end	Day	6% 4 1 5% 3 3 4 3 4 6% 60%	1665
March	1st to 10th	Day	5% 3 1 4 2 3 3 3 5% 6% 64%	3554
	11th to 20th	Day	7% 5% 2 4 3 3 3 3 5% 7% 58%	3600
	21st to end	Day	6% 5% 1 5% 3 3 3 3 4 5% 61%	3892
April	1st to 10th	Day	3 2 1 3 2 2 3 3 5% 8% 68%	2090
	11th to 20th	Day	1 2 1 3 2 2 3 2 4 5% 75%	2180
	21st to end	Day	2 2 1 2 2 2 2 2 4 5% 76%	2446
May	1st to 10th	Day	1 1 1 1 1 1 1 2 4 86%	4110
	11th to 20th	Day	2 2 1 2 2 2 3 2 3 5% 76%	4071
	21st to end	Day	1 1 1 1 1 1 1 2 4 88%	4477
June	1st to 10th	Day	1 2 1 2 2 1 2 2 3 4 81%	2470
	11th to 20th	Day	1 1 1 1 1 2 1 2 3 87%	2470
	21st to end	Day	1 2 1 3 2 2 3 2 4 5% 75%	2470
July	1st to 10th	Day	1 2 1 2 2 2 3 3 4 5% 75%	4110
	11th to 20th	Day	2 2 1 4 3 4 5% 4 8% 10% 58%	4110
	21st to end	Day	3 3 1 3 4 4 6% 6% 8% 11% 50%	4454
August	1st to 10th	Day	3 3 2 4 3 4 5% 5% 8% 11% 53%	4092
	11th to 20th	Day	2 2 1 3 3 3 4 4 6% 8% 65%	4028
	21st to end	Day	2 2 1 3 3 3 4 3 5% 7% 66%	4143
September	1st to 10th	Day	4 3 1 4 3 3 3 3 5% 6% 64%	2090
	11th to 20th	Day	2 2 1 2 2 2 2 2 3 5% 78%	2090
	21st to end	Day	2 2 1 3 2 2 3 2 3 4 76%	2090
October	1st to 10th	Day	2 1 1 1 2 2 2 2 3 4 80%	3408
	11th to 20th	Day	3 1 1 1 1 1 1 2 3 84%	3150
	21st to end	Day	1 1 1 2 2 2 2 2 4 6% 79%	3438
November	1st to 10th	Day	2 2 1 3 2 2 2 3 4 5% 73%	1959
	11th to 20th	Day	1 2 1 4 2 2 2 2 4 4 75%	1830
	21st to end	Day	6% 4 2 4 3 2 3 2 4 6% 65%	1800
December	1st to 10th	Day	4 3 1 2 2 2 2 2 3 3 75%	2950
	11th to 20th	Day	5% 4 2 5% 3 3 3 4 8% 8% 56%	3409
	21st to end	Day	7% 4 1 4 3 3 4 3 4 6% 60%	4510
January	1st to 10th	Night	4 4 2 4 3 3 3 3 4 5% 64%	5867
	11th to 20th	Night	3 2 1 3 2 2 2 2 3 4 77%	5880
	21st to end	Night	10% 5% 2 4 3 3 4 3 4 5% 57%	6468
February	1st to 10th	Night	6% 4 1 4 2 2 3 3 5% 6% 64%	2532
	11th to 20th	Night	7% 5% 2 4 3 3 4 3 4 6% 60%	2338
	21st to end	Night	8% 4 1 5% 3 3 3 3 4 5% 60%	1964
March	1st to 10th	Night	4 3 1 3 2 2 3 3 5% 7% 69%	3540
	11th to 20th	Night	7% 3 1 4 4 4 3 3 4 6% 60%	3600
	21st to end	Night	7% 4 1 3 2 3 3 3 5% 8% 59%	3899
April	1st to 10th	Night	3 2 1 3 3 2 3 3 5% 6% 68%	2090
	11th to 20th	Night	2 3 1 2 2 2 2 2 4 5% 75%	1948
	21st to end	Night	2 2 1 2 2 2 1 2 3 4 80%	1729
May	1st to 10th	Night	1 1 2 1 2 2 2 3 4 84%	2860
	11th to 20th	Night	1 1 1 2 2 2 2 2 3 4 80%	2834
	21st to end	Night	1 1 1 1 1 1 1 3 90%	3110
June	1st to 10th	Night	1 2 2 2 1 3 3 4 5% 77%	1710
	11th to 20th	Night	1 1 1 1 1 1 1 1 2 3 86%	1710
	21st to end	Night	2 2 1 3 2 2 2 2 3 4 76%	1710
July	1st to 10th	Night	1 2 1 3 3 3 4 4 5% 6% 70%	2860
	11th to 20th	Night	1 2 1 4 4 4 5% 5% 7% 13% 54%	2860
	21st to end	Night	2 3 1 5% 4 5% 6% 6% 10% 15% 44%	3109
August	1st to 10th	Night	2 3 2 5% 5% 6% 7% 8% 11% 14% 39%	2847
	11th to 20th	Night	1 2 1 3 3 4 5% 4 6% 10% 61%	2811
	21st to end	Night	2 3 1 4 4 3 5% 4 5% 7% 62%	3510
September	1st to 10th	Night	4 3 1 4 3 3 5% 4 6% 9% 59%	2090
	11th to 20th	Night	2 2 1 2 2 3 2 2 4 5% 76%	2090
	21st to end	Night	2 2 1 3 2 2 3 2 4 5% 74%	2090
October	1st to 10th	Night	2 2 1 2 2 2 2 2 3 4 79%	3568
	11th to 20th	Night	2 1 2 1 1 1 1 3 5% 83%	3778
	21st to end	Night	3 1 1 2 2 2 2 2 3 5% 78%	4120
November	1st to 10th	Night	3 2 1 3 2 2 3 3 4 5% 72%	2340
	11th to 20th	Night	2 2 1 3 2 2 3 1 4 5% 76%	2565
	21st to end	Night	6% 3 1 4 3 2 3 3 4 5% 66%	2600
December	1st to 10th	Night	4 2 1 2 2 2 2 2 4 6% 73%	4240
	11th to 20th	Night	5% 3 1 5% 4 3 3 3 4 6% 63%	4811
	21st to end	Night	7% 4 2 4 3 3 3 3 3 4 64%	6468

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	22% 2 3 11% 38% 25%	4099
	11th to 20th	Day	17% 2 3 14% 25% 39%	4100
	21st to end	Day	28% 3 3 10% 29% 27%	4510
February	1st to 10th	Day	22% 2 5% 13% 26% 31%	1865
	11th to 20th	Day	26% 3 4 15% 25% 26%	1960
	21st to end	Day	24% 3 4 14% 27% 28%	1665
March	1st to 10th	Day	20% 2 5% 16% 36% 21%	3554
	11th to 20th	Day	24% 2 7% 19% 29% 19%	3600
	21st to end	Day	24% 4 4 16% 36% 17%	3892
April	1st to 10th	Day	15% 1 4 10% 36% 34%	2090
	11th to 20th	Day	13% 1 3 8% 25% 49%	2183
	21st to end	Day	12% 1 3 8% 27% 49%	2446
May	1st to 10th	Day	6% 1 3 8% 24% 58%	4110
	11th to 20th	Day	11% 1 4 6% 22% 56%	4074
	21st to end	Day	5% 2 4 16% 74%	4477
June	1st to 10th	Day	9% 1 3 4 25% 59%	2470
	11th to 20th	Day	6% 2 2 11% 78%	2470
	21st to end	Day	12% 2 4 6% 15% 60%	2470
July	1st to 10th	Day	12% 2 5% 7% 12% 62%	4046
	11th to 20th	Day	19% 4 8% 27% 29% 13%	4041
	21st to end	Day	24% 5% 11% 27% 22% 11%	4314
August	1st to 10th	Day	23% 4 12% 29% 14% 17%	4078
	11th to 20th	Day	17% 4 7% 20% 30% 21%	4067
	21st to end	Day	17% 3 7% 15% 30% 28%	4142
September	1st to 10th	Day	20% 3 6% 13% 24% 34%	2090
	11th to 20th	Day	11% 2 3 8% 28% 47%	2090
	21st to end	Day	12% 2 4 6% 25% 50%	2090
October	1st to 10th	Day	11% 2 3 7% 19% 59%	3408
	11th to 20th	Day	9% 1 2 5% 35% 48%	3150
	21st to end	Day	10% 1 2 6% 26% 55%	3438
November	1st to 10th	Day	13% 1 4 12% 31% 39%	1959
	11th to 20th	Day	14% 1 2 12% 27% 44%	1830
	21st to end	Day	23% 1 4 11% 26% 35%	1800
December	1st to 10th	Day	16% 2 2 13% 37% 30%	2950
	11th to 20th	Day	25% 2 4 13% 28% 27%	3408
	21st to end	Day	27% 2 4 24% 29% 14%	4510
January	1st to 10th	Night	23% 1 4 11% 39% 23%	5867
	11th to 20th	Night	14% 1 3 15% 32% 35%	5880
	21st to end	Night	30% 3 3 9% 27% 28%	6468
February	1st to 10th	Night	22% 2 5% 12% 26% 34%	2532
	11th to 20th	Night	26% 3 4 16% 25% 27%	2339
	21st to end	Night	26% 2 5% 10% 26% 32%	1964
March	1st to 10th	Night	15% 2 5% 19% 34% 25%	3540
	11th to 20th	Night	23% 2 7% 16% 29% 23%	3600
	21st to end	Night	21% 2 7% 18% 32% 20%	3899
April	1st to 10th	Night	17% 1 5% 10% 29% 38%	2090
	11th to 20th	Night	13% 1 3 6% 26% 50%	1948
	21st to end	Night	10% 1 3 8% 24% 53%	1729
May	1st to 10th	Night	7% 1 3 7% 23% 58%	2860
	11th to 20th	Night	9% 1 4 6% 19% 62%	2835
	21st to end	Night	5% 1 3 14% 76%	3110
June	1st to 10th	Night	11% 1 3 3 19% 64%	1710
	11th to 20th	Night	6% 1 2 3 11% 78%	1710
	21st to end	Night	13% 1 4 5% 12% 64%	1710
July	1st to 10th	Night	15% 3 4 7% 12% 59%	2815
	11th to 20th	Night	21% 4 8% 20% 32% 16%	2806
	21st to end	Night	25% 5% 13% 24% 20% 13%	3011
August	1st to 10th	Night	31% 4 16% 22% 11% 17%	2838
	11th to 20th	Night	19% 4 9% 20% 25% 24%	2838
	21st to end	Night	21% 3 8% 12% 21% 34%	3510
September	1st to 10th	Night	21% 4 8% 17% 18% 32%	2090
	11th to 20th	Night	12% 2 4 8% 25% 49%	2090
	21st to end	Night	14% 2 4 5% 21% 54%	2090
October	1st to 10th	Night	12% 1 2 6% 16% 61%	3568
	11th to 20th	Night	8% 1 1 8% 25% 56%	3778
	21st to end	Night	12% 1 2 5% 19% 61%	4120
November	1st to 10th	Night	14% 1 3 11% 30% 40%	2340
	11th to 20th	Night	13% 1 3 12% 25% 45%	2565
	21st to end	Night	22% 2 4 9% 27% 36%	2600
December	1st to 10th	Night	15% 1 3 15% 34% 33%	4240
	11th to 20th	Night	25% 2 3 9% 28% 33%	4811
	21st to end	Night	25% 2 5% 20% 30% 19%	6468

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	14% 6% 28% 37% 13% 2	300
	11th to 20th	Day	12% 5% 27% 36% 19% 2	300
	21st to end	Day	11% 8% 26% 35% 16% 5%	330
February	1st to 10th	Day	8% 7% 30% 33% 18% 3	365
	11th to 20th	Day	12% 12% 34% 28% 14% 1	495
	21st to end	Day	12% 13% 37% 27% 10% 1	414
March	1st to 10th	Day	8% 14% 35% 30% 11% 2	500
	11th to 20th	Day	10% 13% 30% 31% 14% 3	500
	21st to end	Day	8% 15% 34% 31% 11% 2	531
April	1st to 10th	Day	6% 10% 33% 31% 17% 3	460
	11th to 20th	Day	4 15% 33% 33% 12% 2	452
	21st to end	Day	3 15% 33% 28% 17% 4	460
May	1st to 10th	Day	3 11% 29% 36% 18% 3	463
	11th to 20th	Day	3 7% 29% 37% 19% 5%	488
	21st to end	Day	3 8% 28% 39% 18% 3	529
June	1st to 10th	Day	2 4 20% 41% 26% 6%	490
	11th to 20th	Day	3 3 28% 37% 24% 6%	490
	21st to end	Day	2 2 18% 44% 27% 8%	490
July	1st to 10th	Day	2 11% 40% 35% 11%	486
	11th to 20th	Day	3 6% 37% 38% 16%	484
	21st to end	Day	4 6% 30% 40% 20%	531
August	1st to 10th	Day	4 1 6% 35% 36% 18%	487
	11th to 20th	Day	3 7% 36% 40% 13%	477
	21st to end	Day	1 1 7% 34% 41% 16%	539
September	1st to 10th	Day	4 1 10% 40% 37% 7%	490
	11th to 20th	Day	3 2 15% 44% 28% 6%	490
	21st to end	Day	3 5% 18% 38% 29% 7%	490
October	1st to 10th	Day	4 5% 22% 39% 26% 4	447
	11th to 20th	Day	3 4 20% 37% 27% 8%	300
	21st to end	Day	2 6% 20% 37% 26% 8%	330
November	1st to 10th	Day	5% 4 22% 42% 24% 3	300
	11th to 20th	Day	6% 5% 23% 36% 25% 6%	300
	21st to end	Day	6% 5% 32% 33% 18% 5%	300
December	1st to 10th	Day	7% 5% 24% 39% 23% 3	300
	11th to 20th	Day	6% 5% 25% 38% 23% 2	300
	21st to end	Day	17% 6% 28% 31% 16% 2	330
January	1st to 10th	Night	9% 2 25% 43% 19% 3	800
	11th to 20th	Night	8% 3 23% 43% 21% 2	800
	21st to end	Night	12% 4 22% 43% 17% 2	880
February	1st to 10th	Night	8% 4 23% 42% 21% 2	800
	11th to 20th	Night	9% 3 23% 48% 16% 1	784
	21st to end	Night	10% 5% 25% 41% 17% 2	660
March	1st to 10th	Night	7% 4 25% 47% 16% 1	800
	11th to 20th	Night	9% 4 21% 37% 26% 4	800
	21st to end	Night	6% 5% 20% 43% 23% 3	862
April	1st to 10th	Night	4 4 17% 53% 21% 2	760
	11th to 20th	Night	3 5% 23% 45% 22% 2	634
	21st to end	Night	2 2 22% 46% 25% 3	570
May	1st to 10th	Night	2 4 14% 51% 27% 2	570
	11th to 20th	Night	2 2 14% 49% 29% 3	561
	21st to end	Night	3 1 14% 48% 31% 4	617
June	1st to 10th	Night	2 1 8% 47% 40% 2	570
	11th to 20th	Night	1 1 8% 49% 37% 3	570
	21st to end	Night	3 7% 38% 48% 5%	570
July	1st to 10th	Night	2 5% 35% 55% 4	555
	11th to 20th	Night	3 1 2 20% 67% 9%	552
	21st to end	Night	4 1 4 20% 60% 11%	624
August	1st to 10th	Night	2 1 2 22% 62% 11%	567
	11th to 20th	Night	2 1 3 24% 63% 6%	564
	21st to end	Night	3 1 3 26% 60% 8%	721
September	1st to 10th	Night	5% 2 4 32% 50% 7%	760
	11th to 20th	Night	3 1 6% 44% 43% 5%	760
	21st to end	Night	3 2 10% 44% 35% 6%	760
October	1st to 10th	Night	5% 1 13% 47% 32% 2	760
	11th to 20th	Night	3 1 16% 43% 34% 3	760
	21st to end	Night	2 3 17% 42% 30% 7%	836
November	1st to 10th	Night	4 1 17% 47% 27% 4	780
	11th to 20th	Night	2 2 19% 46% 26% 4	800
	21st to end	Night	8% 3 20% 43% 24% 2	800
December	1st to 10th	Night	8% 3 19% 45% 23% 1	800
	11th to 20th	Night	11% 3 20% 44% 21% 2	800
	21st to end	Night	11% 2 22% 43% 20% 2	880

Page generated at 2025-03-24 06:04:30. Version ac07

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