Wolf Creek Observing Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wolf Creek Observing Site clear sky chart from 2005-11-06 to 2026-02-16.

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	4 8% 3 8% 5% 4 4 4 5% 7% 49%	139684
	Night	2 6% 3 7% 5% 4 4 4 5% 7% 54%	138712
Transparency	Day	30% 7% 12% 20% 21% 11%	134444
	Night	25% 7% 13% 23% 22% 10%	134957
Seeing	Day	13% 22% 32% 21% 9% 2	16857
	Night	8% 15% 28% 31% 15% 2	27264

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	1 9% 5% 15% 6% 6% 5% 4 6% 8% 36%	5318
	11th to 20th	Day	1 5% 4 12% 6% 4 3 3 5% 5% 53%	5340
	21st to end	Day	1 8% 4 7% 4 3 3 3 5% 7% 56%	5844
February	1st to 10th	Day	1 12% 6% 11% 6% 6% 4 4 5% 5% 39%	1890
	11th to 20th	Day	2 14% 7% 11% 7% 4 5% 4 5% 7% 34%	1823
	21st to end	Day	2 12% 7% 14% 7% 5% 4 3 4 6% 35%	1650
March	1st to 10th	Day	1 14% 8% 15% 5% 3 3 3 5% 6% 37%	4923
	11th to 20th	Day	1 12% 4 12% 5% 5% 5% 4 7% 7% 38%	5000
	21st to end	Day	3 18% 8% 13% 6% 5% 5% 4 4 5% 29%	5486
April	1st to 10th	Day	3 14% 4 11% 5% 5% 4 4 5% 7% 39%	2256
	11th to 20th	Day	3 14% 5% 11% 6% 4 5% 3 6% 7% 36%	2460
	21st to end	Day	5% 12% 4 9% 5% 4 4 3 5% 6% 42%	2600
May	1st to 10th	Day	6% 11% 5% 10% 5% 4 5% 4 5% 7% 37%	5880
	11th to 20th	Day	6% 10% 2 6% 4 5% 5% 4 6% 9% 43%	5841
	21st to end	Day	5% 8% 2 6% 5% 5% 6% 4 6% 7% 46%	6464
June	1st to 10th	Day	5% 5% 2 5% 5% 5% 4 4 5% 8% 53%	2800
	11th to 20th	Day	6% 4 2 4 3 4 4 3 5% 5% 60%	2800
	21st to end	Day	3 4 2 4 3 4 3 4 5% 7% 62%	2758
July	1st to 10th	Day	4 3 1 4 3 3 4 3 4 5% 66%	5879
	11th to 20th	Day	4 3 2 5% 4 5% 5% 5% 8% 9% 51%	5880
	21st to end	Day	4 4 1 5% 4 4 5% 4 6% 7% 56%	6401
August	1st to 10th	Day	3 2 1 3 3 4 4 3 5% 7% 64%	5779
	11th to 20th	Day	3 2 1 4 3 4 5% 4 6% 7% 61%	5798
	21st to end	Day	7% 4 1 6% 5% 5% 6% 4 6% 7% 49%	6319
September	1st to 10th	Day	7% 4 1 4 4 4 4 3 4 7% 58%	2320
	11th to 20th	Day	7% 5% 1 5% 4 3 4 4 4 6% 57%	2200
	21st to end	Day	7% 5% 1 4 3 3 3 3 3 5% 63%	2200
October	1st to 10th	Day	6% 6% 1 4 3 2 2 3 4 5% 64%	3374
	11th to 20th	Day	6% 7% 2 6% 4 3 3 3 5% 5% 55%	3250
	21st to end	Day	4 7% 3 5% 3 3 3 4 5% 6% 59%	3548
November	1st to 10th	Day	5% 9% 3 6% 4 4 3 3 6% 6% 51%	1905
	11th to 20th	Day	2 10% 3 6% 4 4 4 5% 5% 7% 49%	1861
	21st to end	Day	1 7% 3 9% 6% 4 4 4 5% 7% 48%	1680
December	1st to 10th	Day	1 6% 2 6% 4 3 4 3 4 8% 59%	2700
	11th to 20th	Day	1 8% 4 10% 5% 5% 5% 4 8% 9% 41%	3106
	21st to end	Day	1 9% 4 11% 5% 6% 5% 5% 8% 7% 39%	4351
January	1st to 10th	Night	1 6% 4 14% 8% 5% 4 4 6% 8% 39%	7605
	11th to 20th	Night	1 6% 3 10% 7% 4 3 3 4 5% 55%	7650
	21st to end	Night	1 6% 3 8% 5% 3 3 3 5% 8% 55%	8370
February	1st to 10th	Night	1 9% 4 10% 6% 5% 4 4 6% 8% 43%	2730
	11th to 20th	Night	2 9% 4 9% 6% 5% 5% 4 6% 7% 42%	2572
	21st to end	Night	2 8% 3 10% 8% 5% 5% 4 6% 8% 41%	1980
March	1st to 10th	Night	1 11% 4 10% 6% 5% 5% 4 5% 6% 42%	4970
	11th to 20th	Night	1 7% 3 9% 6% 6% 6% 5% 6% 9% 42%	5000
	21st to end	Night	2 10% 3 10% 6% 4 4 4 6% 7% 44%	5489
April	1st to 10th	Night	3 11% 3 6% 6% 4 3 3 5% 6% 50%	2142
	11th to 20th	Night	2 8% 3 7% 4 5% 5% 4 6% 7% 47%	1885
	21st to end	Night	4 9% 2 7% 4 5% 4 4 7% 7% 48%	1800
May	1st to 10th	Night	3 8% 4 7% 5% 4 5% 4 5% 6% 49%	4100
	11th to 20th	Night	3 6% 2 5% 4 3 4 3 6% 7% 57%	4074
	21st to end	Night	4 5% 2 5% 3 3 4 4 5% 8% 57%	4428
June	1st to 10th	Night	5% 4 2 5% 4 4 4 3 6% 8% 57%	1600
	11th to 20th	Night	4 3 1 5% 3 3 4 2 4 6% 64%	1600
	21st to end	Night	2 2 1 3 3 3 3 3 5% 6% 68%	1634
July	1st to 10th	Night	2 2 1 3 3 3 4 2 5% 5% 70%	4100
	11th to 20th	Night	2 3 1 4 4 4 5% 5% 7% 9% 56%	4100
	21st to end	Night	2 2 1 4 4 5% 5% 4 6% 6% 62%	4472
August	1st to 10th	Night	3 2 1 3 3 3 4 3 5% 7% 66%	4033
	11th to 20th	Night	3 3 1 4 4 4 4 4 5% 6% 62%	4051
	21st to end	Night	3 3 1 5% 4 5% 5% 4 6% 7% 56%	4656
September	1st to 10th	Night	4 3 1 4 2 2 3 3 5% 6% 66%	2075
	11th to 20th	Night	6% 3 1 3 3 2 4 4 5% 7% 63%	2200
	21st to end	Night	7% 4 1 3 2 2 3 2 4 5% 67%	2200
October	1st to 10th	Night	4 4 1 3 2 2 2 2 3 4 72%	3819
	11th to 20th	Night	5% 4 1 4 4 3 4 4 5% 6% 60%	3898
	21st to end	Night	2 6% 2 5% 3 2 3 3 5% 8% 60%	4252
November	1st to 10th	Night	2 7% 3 6% 4 3 4 4 6% 7% 54%	2610
	11th to 20th	Night	2 7% 2 6% 5% 3 4 5% 6% 7% 53%	2735
	21st to end	Night	2 8% 3 8% 5% 4 4 4 5% 6% 51%	2940
December	1st to 10th	Night	1 5% 2 7% 3 3 3 3 4 8% 62%	4710
	11th to 20th	Night	1 9% 3 6% 5% 4 5% 4 6% 9% 47%	5321
	21st to end	Night	1 9% 5% 10% 6% 6% 5% 4 6% 8% 40%	6911

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	36% 11% 18% 22% 11% 3	5321
	11th to 20th	Day	26% 10% 11% 22% 23% 8%	5340
	21st to end	Day	25% 5% 17% 19% 25% 9%	5844
February	1st to 10th	Day	40% 12% 14% 20% 10% 5%	1890
	11th to 20th	Day	41% 11% 13% 21% 11% 3	1832
	21st to end	Day	44% 10% 12% 19% 12% 4	1650
March	1st to 10th	Day	43% 5% 10% 18% 16% 7%	4923
	11th to 20th	Day	37% 8% 18% 23% 12% 1	5000
	21st to end	Day	49% 8% 19% 17% 6% 1	5486
April	1st to 10th	Day	37% 9% 15% 21% 14% 4	2256
	11th to 20th	Day	42% 9% 13% 21% 14% 1	2463
	21st to end	Day	38% 7% 13% 27% 14% 1	2600
May	1st to 10th	Day	33% 13% 12% 22% 17% 2	5880
	11th to 20th	Day	32% 7% 11% 28% 21% 1	5844
	21st to end	Day	30% 7% 10% 25% 25% 2	6465
June	1st to 10th	Day	26% 6% 11% 25% 27% 5%	2800
	11th to 20th	Day	23% 4 8% 18% 28% 18%	2800
	21st to end	Day	19% 5% 6% 14% 31% 26%	2758
July	1st to 10th	Day	19% 4 5% 8% 16% 50%	5816
	11th to 20th	Day	24% 5% 9% 13% 27% 22%	5811
	21st to end	Day	22% 6% 8% 12% 27% 25%	6217
August	1st to 10th	Day	24% 5% 9% 22% 21% 18%	4208
	11th to 20th	Day	22% 5% 9% 16% 30% 18%	4197
	21st to end	Day	24% 6% 8% 15% 25% 22%	4550
September	1st to 10th	Day	24% 5% 8% 17% 26% 21%	2320
	11th to 20th	Day	27% 5% 8% 18% 26% 16%	2200
	21st to end	Day	22% 5% 7% 21% 33% 11%	2200
October	1st to 10th	Day	23% 3 6% 18% 35% 15%	3374
	11th to 20th	Day	29% 3 9% 30% 25% 4	3250
	21st to end	Day	24% 4 12% 27% 28% 4	3548
November	1st to 10th	Day	30% 7% 14% 24% 21% 4	1905
	11th to 20th	Day	28% 7% 18% 25% 20% 2	1861
	21st to end	Day	29% 8% 14% 26% 16% 6%	1680
December	1st to 10th	Day	21% 7% 13% 34% 21% 4	2700
	11th to 20th	Day	30% 9% 18% 24% 17% 2	3104
	21st to end	Day	36% 9% 13% 15% 19% 7%	4351
January	1st to 10th	Night	33% 12% 17% 18% 16% 3	7605
	11th to 20th	Night	26% 8% 10% 24% 24% 7%	7650
	21st to end	Night	23% 7% 16% 21% 25% 9%	8370
February	1st to 10th	Night	31% 12% 17% 23% 13% 4	2730
	11th to 20th	Night	32% 10% 15% 22% 19% 3	2573
	21st to end	Night	32% 9% 17% 21% 14% 6%	1980
March	1st to 10th	Night	35% 6% 15% 21% 18% 6%	4970
	11th to 20th	Night	31% 10% 17% 27% 13% 2	5000
	21st to end	Night	29% 9% 23% 26% 12% 1	5489
April	1st to 10th	Night	29% 9% 16% 21% 19% 6%	2142
	11th to 20th	Night	28% 8% 17% 27% 17% 3	1885
	21st to end	Night	29% 7% 18% 29% 17% 1	1800
May	1st to 10th	Night	26% 12% 11% 25% 23% 2	4097
	11th to 20th	Night	22% 6% 11% 33% 25% 4	4075
	21st to end	Night	22% 5% 11% 34% 26% 2	4428
June	1st to 10th	Night	23% 6% 13% 24% 28% 6%	1600
	11th to 20th	Night	20% 4 9% 17% 32% 18%	1600
	21st to end	Night	16% 4 4 17% 29% 29%	1634
July	1st to 10th	Night	17% 3 5% 9% 15% 51%	4055
	11th to 20th	Night	22% 4 8% 13% 28% 27%	4046
	21st to end	Night	20% 5% 8% 14% 28% 25%	4344
August	1st to 10th	Night	21% 4 11% 21% 22% 20%	2928
	11th to 20th	Night	25% 6% 9% 17% 25% 19%	2928
	21st to end	Night	18% 6% 10% 16% 27% 23%	3356
September	1st to 10th	Night	19% 4 9% 20% 27% 22%	2075
	11th to 20th	Night	19% 4 10% 22% 29% 16%	2200
	21st to end	Night	19% 4 7% 20% 38% 13%	2200
October	1st to 10th	Night	16% 3 7% 23% 34% 17%	3819
	11th to 20th	Night	22% 4 10% 32% 26% 6%	3898
	21st to end	Night	20% 5% 11% 33% 29% 3	4252
November	1st to 10th	Night	24% 7% 16% 24% 23% 6%	2610
	11th to 20th	Night	23% 7% 19% 30% 19% 3	2735
	21st to end	Night	29% 7% 13% 25% 19% 7%	2940
December	1st to 10th	Night	19% 7% 13% 32% 23% 6%	4710
	11th to 20th	Night	27% 8% 20% 29% 14% 2	5322
	21st to end	Night	35% 9% 16% 19% 14% 7%	6911

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	22% 24% 27% 18% 9% 1	330
	11th to 20th	Day	19% 27% 28% 17% 7% 2	330
	21st to end	Day	12% 31% 34% 18% 5% 1	363
February	1st to 10th	Day	25% 32% 31% 9% 3 1	330
	11th to 20th	Day	21% 33% 27% 14% 4 1	338
	21st to end	Day	19% 34% 33% 10% 3	414
March	1st to 10th	Day	17% 33% 30% 15% 5% 1	500
	11th to 20th	Day	14% 31% 31% 21% 2 1	500
	21st to end	Day	17% 38% 33% 11% 2	550
April	1st to 10th	Day	21% 27% 28% 17% 5% 3	500
	11th to 20th	Day	22% 29% 31% 13% 4 1	492
	21st to end	Day	20% 28% 29% 18% 5% 1	500
May	1st to 10th	Day	20% 25% 32% 15% 7% 1	503
	11th to 20th	Day	18% 24% 31% 17% 8% 2	528
	21st to end	Day	15% 20% 31% 20% 11% 2	588
June	1st to 10th	Day	7% 15% 34% 26% 15% 3	730
	11th to 20th	Day	10% 21% 35% 22% 11% 1	730
	21st to end	Day	7% 14% 40% 25% 12% 2	688
July	1st to 10th	Day	5% 12% 37% 33% 11% 2	526
	11th to 20th	Day	6% 10% 43% 27% 10% 3	524
	21st to end	Day	6% 7% 38% 30% 15% 3	575
August	1st to 10th	Day	8% 12% 41% 26% 10% 3	527
	11th to 20th	Day	5% 11% 36% 33% 12% 3	517
	21st to end	Day	7% 13% 32% 31% 12% 5%	583
September	1st to 10th	Day	6% 13% 32% 29% 14% 5%	530
	11th to 20th	Day	10% 20% 32% 23% 12% 3	530
	21st to end	Day	12% 16% 27% 26% 16% 3	530
October	1st to 10th	Day	12% 20% 27% 22% 15% 4	395
	11th to 20th	Day	18% 21% 25% 20% 14% 2	330
	21st to end	Day	15% 24% 30% 21% 9% 1	363
November	1st to 10th	Day	17% 25% 26% 20% 10% 1	330
	11th to 20th	Day	15% 19% 37% 19% 7% 3	330
	21st to end	Day	15% 18% 32% 23% 10% 2	330
December	1st to 10th	Day	15% 25% 29% 20% 8% 3	330
	11th to 20th	Day	13% 29% 30% 23% 4 1	330
	21st to end	Day	21% 28% 27% 18% 5% 1	363
January	1st to 10th	Night	11% 20% 29% 27% 11% 2	840
	11th to 20th	Night	10% 21% 32% 27% 10% 2	840
	21st to end	Night	6% 22% 35% 27% 9% 2	924
February	1st to 10th	Night	10% 25% 37% 18% 8% 2	840
	11th to 20th	Night	9% 24% 34% 23% 8% 1	804
	21st to end	Night	9% 24% 36% 25% 6%	660
March	1st to 10th	Night	10% 21% 32% 29% 7% 2	800
	11th to 20th	Night	7% 15% 31% 32% 13% 1	800
	21st to end	Night	10% 23% 33% 26% 7% 1	880
April	1st to 10th	Night	10% 22% 31% 26% 9% 1	742
	11th to 20th	Night	10% 20% 34% 28% 7%	593
	21st to end	Night	11% 21% 31% 26% 11% 1	600
May	1st to 10th	Night	7% 18% 33% 29% 12% 1	600
	11th to 20th	Night	8% 8% 27% 37% 17% 3	591
	21st to end	Night	10% 13% 26% 31% 18% 2	650
June	1st to 10th	Night	6% 11% 26% 36% 19% 2	600
	11th to 20th	Night	7% 13% 31% 35% 13% 1	600
	21st to end	Night	4 5% 28% 39% 22% 3	600
July	1st to 10th	Night	5% 3 19% 39% 31% 3	585
	11th to 20th	Night	7% 2 17% 43% 27% 3	582
	21st to end	Night	4 1 12% 45% 37% 2	657
August	1st to 10th	Night	6% 3 16% 47% 26% 2	597
	11th to 20th	Night	6% 3 16% 43% 29% 4	594
	21st to end	Night	4 3 17% 43% 30% 3	660
September	1st to 10th	Night	5% 4 19% 36% 31% 5%	675
	11th to 20th	Night	5% 6% 21% 36% 28% 5%	800
	21st to end	Night	8% 9% 17% 35% 24% 7%	800
October	1st to 10th	Night	8% 12% 27% 32% 18% 3	800
	11th to 20th	Night	9% 16% 23% 33% 16% 3	800
	21st to end	Night	7% 17% 28% 31% 15% 3	880
November	1st to 10th	Night	7% 17% 29% 32% 13% 2	820
	11th to 20th	Night	7% 21% 32% 28% 10% 2	845
	21st to end	Night	10% 19% 28% 30% 11% 3	1050
December	1st to 10th	Night	11% 19% 33% 27% 9% 1	1050
	11th to 20th	Night	9% 21% 34% 27% 8% 1	1050
	21st to end	Night	11% 23% 37% 22% 6% 1	1055

Page generated at 2026-02-12 23:42:11. Version ac07

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