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 2024-01-15.

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	5% 8% 4 7% 6% 3 5% 5% 5% 7% 46%	74638
	Night	3 6% 3 6% 6% 3 5% 5% 6% 7% 50%	75158
Transparency	Day	34% 7% 12% 20% 18% 8%	74363
	Night	28% 8% 15% 22% 19% 8%	74954
Seeing	Day	13% 21% 33% 22% 9% 2	14057
	Night	8% 15% 28% 31% 16% 2	24443

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	2 11% 5% 9% 7% 4 4 5% 5% 7% 41%	1708
	11th to 20th	Day	1 8% 6% 9% 8% 4 4 4 6% 6% 45%	1656
	21st to end	Day	3 11% 5% 11% 6% 3 4 4 4 6% 43%	1782
February	1st to 10th	Day	1 11% 6% 12% 7% 4 6% 5% 5% 5% 38%	1620
	11th to 20th	Day	3 13% 8% 9% 8% 2 4 6% 5% 7% 36%	1595
	21st to end	Day	3 11% 9% 13% 9% 3 6% 4 4 6% 31%	1480
March	1st to 10th	Day	2 14% 5% 10% 8% 3 4 5% 6% 7% 34%	1962
	11th to 20th	Day	3 12% 6% 9% 7% 4 4 5% 6% 8% 37%	1980
	21st to end	Day	4 15% 7% 11% 9% 4 5% 5% 4 6% 30%	2178
April	1st to 10th	Day	4 13% 5% 9% 6% 3 5% 4 5% 7% 38%	2030
	11th to 20th	Day	4 13% 6% 10% 7% 3 5% 4 5% 7% 34%	2210
	21st to end	Day	5% 11% 5% 8% 5% 3 4 4 5% 6% 43%	2340
May	1st to 10th	Day	6% 9% 4 6% 7% 4 6% 6% 6% 7% 39%	2340
	11th to 20th	Day	8% 11% 3 6% 5% 4 5% 5% 5% 8% 40%	2301
	21st to end	Day	9% 12% 3 6% 8% 4 6% 6% 5% 8% 34%	2543
June	1st to 10th	Day	6% 5% 2 4 5% 3 5% 4 5% 7% 53%	2520
	11th to 20th	Day	7% 4 2 4 4 3 4 4 5% 5% 59%	2520
	21st to end	Day	4 4 2 3 4 3 3 5% 5% 7% 62%	2483
July	1st to 10th	Day	7% 4 2 5% 5% 3 5% 6% 6% 8% 50%	2340
	11th to 20th	Day	7% 5% 3 5% 6% 4 5% 4 6% 7% 49%	2340
	21st to end	Day	8% 5% 2 5% 6% 4 5% 6% 6% 7% 45%	2545
August	1st to 10th	Day	7% 4 3 5% 5% 3 6% 5% 6% 7% 48%	2328
	11th to 20th	Day	5% 4 1 4 5% 3 5% 5% 6% 7% 56%	2299
	21st to end	Day	6% 4 2 4 5% 3 6% 6% 5% 7% 52%	2516
September	1st to 10th	Day	7% 4 2 3 4 2 4 4 4 7% 60%	2088
	11th to 20th	Day	8% 5% 2 4 4 3 4 4 4 5% 57%	1980
	21st to end	Day	8% 5% 2 3 3 2 3 3 3 5% 63%	1980
October	1st to 10th	Day	10% 10% 2 5% 5% 2 3 4 4 5% 50%	1859
	11th to 20th	Day	5% 7% 3 6% 4 3 3 4 4 5% 58%	1800
	21st to end	Day	4 5% 3 6% 4 3 4 5% 5% 6% 57%	1980
November	1st to 10th	Day	5% 9% 3 5% 5% 3 3 4 5% 6% 51%	1721
	11th to 20th	Day	3 9% 3 5% 5% 3 4 5% 6% 8% 50%	1685
	21st to end	Day	2 7% 4 9% 7% 3 5% 5% 5% 7% 47%	1520
December	1st to 10th	Day	2 10% 3 7% 8% 4 6% 5% 5% 8% 43%	1520
	11th to 20th	Day	2 11% 5% 10% 9% 4 5% 5% 6% 6% 37%	1926
	21st to end	Day	2 8% 4 11% 8% 4 4 4 5% 7% 44%	2963
January	1st to 10th	Night	3 8% 5% 7% 8% 4 5% 5% 6% 8% 42%	2457
	11th to 20th	Night	1 8% 4 8% 7% 4 5% 5% 6% 7% 46%	2392
	21st to end	Night	2 9% 3 8% 8% 3 5% 5% 6% 8% 42%	2574
February	1st to 10th	Night	1 8% 5% 9% 7% 3 5% 5% 7% 8% 44%	2340
	11th to 20th	Night	2 8% 6% 7% 6% 3 5% 6% 6% 7% 43%	2250
	21st to end	Night	2 7% 4 9% 10% 4 6% 6% 6% 8% 39%	1776
March	1st to 10th	Night	3 8% 5% 8% 8% 4 6% 7% 6% 8% 39%	1997
	11th to 20th	Night	2 8% 4 7% 6% 3 4 5% 5% 9% 47%	1980
	21st to end	Night	4 8% 3 8% 7% 3 5% 5% 6% 7% 43%	2178
April	1st to 10th	Night	3 11% 3 5% 6% 4 4 4 5% 6% 49%	1928
	11th to 20th	Night	3 7% 4 6% 6% 4 5% 6% 6% 8% 46%	1695
	21st to end	Night	4 8% 2 6% 4 3 5% 5% 6% 7% 49%	1620
May	1st to 10th	Night	4 7% 3 5% 6% 4 5% 6% 7% 7% 45%	1620
	11th to 20th	Night	4 6% 2 5% 5% 3 4 5% 7% 7% 51%	1594
	21st to end	Night	6% 7% 3 6% 5% 3 6% 6% 7% 8% 44%	1728
June	1st to 10th	Night	5% 4 2 4 4 3 4 4 5% 8% 57%	1440
	11th to 20th	Night	5% 3 1 4 4 2 4 3 4 6% 64%	1440
	21st to end	Night	3 2 1 3 4 2 3 4 5% 6% 67%	1470
July	1st to 10th	Night	3 3 2 4 5% 4 6% 4 6% 8% 55%	1620
	11th to 20th	Night	4 4 2 5% 6% 4 5% 6% 6% 8% 51%	1620
	21st to end	Night	4 3 2 5% 5% 4 6% 7% 8% 8% 48%	1773
August	1st to 10th	Night	6% 3 2 4 5% 3 5% 4 6% 8% 53%	1611
	11th to 20th	Night	4 3 1 4 4 3 4 4 6% 8% 58%	1602
	21st to end	Night	3 3 1 4 4 3 5% 5% 6% 8% 59%	1838
September	1st to 10th	Night	4 3 2 4 3 2 3 3 4 6% 66%	1867
	11th to 20th	Night	6% 3 1 3 3 1 3 5% 5% 7% 63%	1980
	21st to end	Night	7% 5% 1 3 3 1 2 2 3 5% 67%	1980
October	1st to 10th	Night	6% 6% 2 5% 4 2 4 4 4 5% 58%	2101
	11th to 20th	Night	4 4 2 4 4 2 4 4 4 6% 62%	2160
	21st to end	Night	4 6% 2 5% 4 2 3 4 5% 7% 59%	2376
November	1st to 10th	Night	2 7% 3 6% 5% 2 4 5% 6% 8% 53%	2355
	11th to 20th	Night	1 6% 2 5% 5% 3 4 6% 6% 7% 53%	2474
	21st to end	Night	2 8% 3 8% 7% 3 5% 4 5% 7% 50%	2660
December	1st to 10th	Night	2 8% 3 7% 6% 3 5% 5% 5% 8% 48%	2660
	11th to 20th	Night	3 11% 4 7% 7% 4 6% 6% 6% 9% 38%	3271
	21st to end	Night	1 8% 4 8% 8% 5% 7% 6% 5% 8% 40%	4731

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	35% 12% 18% 23% 10% 2	1709
	11th to 20th	Day	34% 13% 17% 17% 16% 4	1656
	21st to end	Day	40% 7% 18% 22% 10% 4	1782
February	1st to 10th	Day	40% 12% 14% 20% 10% 4	1620
	11th to 20th	Day	40% 11% 13% 22% 11% 3	1604
	21st to end	Day	47% 10% 13% 18% 9% 2	1480
March	1st to 10th	Day	44% 8% 14% 22% 10% 1	1962
	11th to 20th	Day	40% 7% 19% 19% 11% 3	1980
	21st to end	Day	49% 9% 15% 18% 7% 2	2178
April	1st to 10th	Day	39% 9% 16% 18% 14% 4	2030
	11th to 20th	Day	43% 10% 13% 20% 13% 1	2213
	21st to end	Day	39% 7% 12% 27% 14% 1	2340
May	1st to 10th	Day	39% 8% 12% 23% 17% 2	2340
	11th to 20th	Day	39% 7% 11% 28% 13% 2	2304
	21st to end	Day	44% 7% 13% 20% 14% 2	2543
June	1st to 10th	Day	27% 6% 11% 24% 26% 6%	2520
	11th to 20th	Day	25% 5% 8% 19% 27% 16%	2520
	21st to end	Day	20% 5% 6% 14% 30% 26%	2483
July	1st to 10th	Day	29% 5% 8% 16% 23% 20%	2276
	11th to 20th	Day	31% 6% 8% 15% 18% 21%	2271
	21st to end	Day	33% 7% 10% 15% 20% 15%	2404
August	1st to 10th	Day	32% 7% 10% 16% 18% 18%	2313
	11th to 20th	Day	26% 5% 8% 15% 28% 18%	2299
	21st to end	Day	29% 6% 8% 19% 26% 13%	2516
September	1st to 10th	Day	25% 5% 7% 16% 25% 23%	2088
	11th to 20th	Day	27% 5% 8% 18% 24% 18%	1980
	21st to end	Day	23% 5% 7% 22% 34% 10%	1980
October	1st to 10th	Day	35% 5% 8% 22% 21% 9%	1859
	11th to 20th	Day	25% 5% 9% 30% 24% 7%	1800
	21st to end	Day	26% 6% 15% 28% 22% 4	1980
November	1st to 10th	Day	32% 7% 14% 23% 21% 3	1721
	11th to 20th	Day	26% 7% 19% 24% 21% 2	1685
	21st to end	Day	31% 8% 15% 24% 16% 6%	1520
December	1st to 10th	Day	34% 12% 17% 20% 10% 5%	1520
	11th to 20th	Day	40% 9% 14% 20% 16% 1	1924
	21st to end	Day	37% 8% 13% 12% 20% 11%	2963
January	1st to 10th	Night	34% 12% 16% 21% 13% 3	2457
	11th to 20th	Night	30% 11% 18% 20% 16% 5%	2392
	21st to end	Night	31% 9% 20% 24% 11% 5%	2574
February	1st to 10th	Night	30% 13% 18% 23% 13% 3	2340
	11th to 20th	Night	31% 10% 16% 22% 19% 3	2251
	21st to end	Night	35% 10% 17% 20% 13% 4	1776
March	1st to 10th	Night	34% 8% 20% 23% 14% 1	1997
	11th to 20th	Night	30% 8% 17% 28% 12% 5%	1980
	21st to end	Night	32% 11% 18% 26% 10% 3	2178
April	1st to 10th	Night	30% 10% 16% 20% 18% 6%	1928
	11th to 20th	Night	29% 8% 18% 27% 15% 2	1695
	21st to end	Night	29% 6% 18% 28% 18% 1	1620
May	1st to 10th	Night	29% 11% 15% 27% 16% 2	1620
	11th to 20th	Night	27% 7% 13% 31% 18% 3	1595
	21st to end	Night	33% 7% 16% 28% 14% 2	1728
June	1st to 10th	Night	24% 6% 13% 25% 26% 7%	1440
	11th to 20th	Night	21% 5% 9% 17% 31% 17%	1440
	21st to end	Night	16% 4 4 18% 27% 30%	1470
July	1st to 10th	Night	25% 5% 10% 15% 23% 21%	1575
	11th to 20th	Night	29% 6% 9% 16% 19% 20%	1566
	21st to end	Night	28% 9% 13% 17% 17% 16%	1674
August	1st to 10th	Night	27% 5% 15% 15% 20% 17%	1602
	11th to 20th	Night	23% 6% 9% 18% 27% 18%	1602
	21st to end	Night	21% 6% 10% 20% 28% 16%	1838
September	1st to 10th	Night	19% 4 8% 19% 26% 24%	1867
	11th to 20th	Night	19% 4 10% 22% 27% 17%	1980
	21st to end	Night	20% 4 6% 19% 38% 12%	1980
October	1st to 10th	Night	26% 5% 11% 25% 23% 9%	2101
	11th to 20th	Night	21% 6% 9% 29% 28% 7%	2160
	21st to end	Night	21% 7% 16% 28% 23% 5%	2376
November	1st to 10th	Night	25% 7% 16% 24% 22% 6%	2355
	11th to 20th	Night	22% 8% 20% 28% 19% 3	2474
	21st to end	Night	30% 7% 13% 23% 20% 8%	2660
December	1st to 10th	Night	30% 10% 19% 23% 14% 5%	2660
	11th to 20th	Night	35% 10% 18% 21% 14% 2	3272
	21st to end	Night	35% 10% 16% 17% 13% 10%	4731

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	20% 22% 27% 20% 10% 1	270
	11th to 20th	Day	15% 27% 31% 19% 8% 1	252
	21st to end	Day	11% 32% 35% 17% 4 1	264
February	1st to 10th	Day	23% 37% 30% 8% 3	240
	11th to 20th	Day	20% 33% 26% 14% 5% 1	260
	21st to end	Day	18% 36% 35% 9% 1 1	346
March	1st to 10th	Day	15% 36% 30% 14% 5%	420
	11th to 20th	Day	13% 30% 32% 22% 2 1	420
	21st to end	Day	16% 38% 34% 11% 1	462
April	1st to 10th	Day	22% 28% 28% 17% 4 2	420
	11th to 20th	Day	23% 30% 31% 11% 3 1	412
	21st to end	Day	21% 28% 27% 19% 5% 1	420
May	1st to 10th	Day	18% 26% 34% 13% 7% 1	423
	11th to 20th	Day	17% 22% 32% 18% 8% 2	448
	21st to end	Day	16% 20% 31% 20% 11% 2	498
June	1st to 10th	Day	8% 15% 34% 25% 15% 3	630
	11th to 20th	Day	10% 20% 35% 21% 12% 1	630
	21st to end	Day	6% 13% 40% 26% 13% 2	593
July	1st to 10th	Day	4 9% 37% 37% 11% 2	446
	11th to 20th	Day	7% 11% 44% 27% 10% 2	444
	21st to end	Day	7% 4 38% 32% 16% 3	487
August	1st to 10th	Day	8% 9% 43% 27% 11% 2	447
	11th to 20th	Day	5% 10% 35% 34% 13% 3	437
	21st to end	Day	7% 10% 33% 33% 13% 4	495
September	1st to 10th	Day	6% 14% 34% 26% 14% 5%	450
	11th to 20th	Day	10% 18% 32% 24% 13% 3	450
	21st to end	Day	14% 17% 26% 25% 15% 3	450
October	1st to 10th	Day	13% 21% 25% 22% 16% 3	329
	11th to 20th	Day	15% 22% 24% 22% 15% 2	270
	21st to end	Day	14% 25% 31% 22% 8%	297
November	1st to 10th	Day	18% 24% 26% 19% 11% 1	270
	11th to 20th	Day	14% 19% 36% 20% 7% 3	270
	21st to end	Day	13% 18% 33% 24% 11% 2	270
December	1st to 10th	Day	12% 24% 33% 21% 8% 3	270
	11th to 20th	Day	10% 29% 32% 24% 4 1	270
	21st to end	Day	18% 30% 27% 20% 5% 1	297
January	1st to 10th	Night	10% 19% 29% 28% 12% 2	760
	11th to 20th	Night	8% 19% 32% 29% 10% 2	736
	21st to end	Night	5% 22% 35% 27% 9% 2	792
February	1st to 10th	Night	10% 24% 38% 19% 8% 2	720
	11th to 20th	Night	8% 24% 33% 25% 9% 1	704
	21st to end	Night	8% 24% 36% 26% 7% 1	592
March	1st to 10th	Night	9% 20% 32% 30% 7% 2	720
	11th to 20th	Night	6% 15% 30% 33% 14% 2	720
	21st to end	Night	9% 22% 34% 26% 8% 1	792
April	1st to 10th	Night	10% 23% 31% 26% 9% 1	668
	11th to 20th	Night	10% 21% 34% 28% 8%	533
	21st to end	Night	11% 21% 30% 25% 12% 1	540
May	1st to 10th	Night	7% 17% 35% 29% 12% 1	540
	11th to 20th	Night	7% 6% 27% 38% 18% 3	531
	21st to end	Night	10% 13% 25% 31% 18% 2	584
June	1st to 10th	Night	7% 11% 26% 35% 20% 2	540
	11th to 20th	Night	7% 14% 29% 36% 14% 1	540
	21st to end	Night	3 5% 28% 39% 23% 3	540
July	1st to 10th	Night	5% 3 16% 39% 34% 3	525
	11th to 20th	Night	7% 2 17% 43% 28% 3	522
	21st to end	Night	4 1 11% 43% 38% 3	591
August	1st to 10th	Night	6% 3 14% 48% 27% 2	537
	11th to 20th	Night	5% 2 15% 43% 31% 4	534
	21st to end	Night	4 3 16% 43% 30% 3	594
September	1st to 10th	Night	5% 5% 21% 36% 29% 5%	607
	11th to 20th	Night	5% 5% 20% 35% 29% 6%	720
	21st to end	Night	8% 10% 18% 32% 25% 8%	720
October	1st to 10th	Night	8% 13% 28% 29% 19% 3	720
	11th to 20th	Night	6% 17% 23% 32% 18% 4	720
	21st to end	Night	7% 17% 26% 31% 16% 3	792
November	1st to 10th	Night	6% 16% 30% 31% 15% 2	740
	11th to 20th	Night	6% 22% 30% 28% 11% 3	764
	21st to end	Night	9% 19% 27% 31% 11% 3	950
December	1st to 10th	Night	9% 19% 35% 28% 8% 1	950
	11th to 20th	Night	8% 20% 35% 28% 8% 1	950
	21st to end	Night	10% 23% 37% 23% 6% 1	955

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