Wolf Creek Estates Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wolf Creek Estates Observatory clear sky chart from 2005-11-06 to 2024-03-08.

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 3 1 4 4 3 4 5% 6% 8% 59%	78785
	Night	2 3 1 3 3 2 4 4 5% 8% 64%	80825
Transparency	Day	23% 8% 8% 17% 27% 17%	78512
	Night	18% 8% 8% 19% 28% 18%	80620
Seeing	Day	11% 18% 27% 25% 15% 3	13884
	Night	8% 15% 25% 30% 19% 3	24218

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 2 1 3 3 2 5% 6% 7% 9% 61%	2858
	11th to 20th	Day	1 2 1 2 3 2 2 3 4 6% 75%	2860
	21st to end	Day	4 5% 2 5% 5% 3 5% 6% 6% 8% 51%	3146
February	1st to 10th	Day	1 4 1 3 3 2 4 4 5% 6% 67%	1844
	11th to 20th	Day	2 3 1 2 3 2 4 4 5% 6% 67%	1849
	21st to end	Day	1 2 1 2 3 2 3 4 5% 5% 72%	1570
March	1st to 10th	Day	1 3 2 3 4 2 4 4 7% 9% 62%	1951
	11th to 20th	Day	2 4 1 4 5% 2 4 4 5% 7% 62%	1980
	21st to end	Day	2 3 2 2 3 2 3 4 5% 8% 67%	2263
April	1st to 10th	Day	2 2 1 2 2 2 4 4 5% 7% 71%	2160
	11th to 20th	Day	3 3 2 3 2 2 4 4 4 5% 69%	2131
	21st to end	Day	2 2 1 2 2 2 3 3 4 6% 73%	2160
May	1st to 10th	Day	2 2 1 3 3 2 3 3 4 7% 71%	2160
	11th to 20th	Day	4 3 2 4 4 3 5% 5% 6% 7% 59%	2125
	21st to end	Day	2 2 1 2 3 2 3 5% 5% 8% 69%	2567
June	1st to 10th	Day	2 2 1 3 3 3 4 6% 7% 9% 62%	2520
	11th to 20th	Day	2 2 1 3 3 2 3 4 5% 7% 70%	2520
	21st to end	Day	7% 4 1 5% 5% 3 6% 6% 7% 9% 48%	2520
July	1st to 10th	Day	9% 4 2 5% 6% 4 9% 7% 9% 10% 35%	2361
	11th to 20th	Day	5% 4 2 6% 6% 5% 8% 9% 9% 12% 35%	2340
	21st to end	Day	7% 4 2 7% 8% 6% 8% 9% 8% 11% 29%	2545
August	1st to 10th	Day	8% 5% 2 7% 7% 5% 8% 8% 9% 10% 31%	2159
	11th to 20th	Day	9% 4 2 7% 7% 4 7% 7% 9% 8% 36%	2123
	21st to end	Day	7% 5% 2 5% 6% 5% 8% 7% 8% 9% 39%	2376
September	1st to 10th	Day	8% 6% 3 6% 6% 4 6% 5% 5% 8% 43%	2160
	11th to 20th	Day	9% 5% 2 4 5% 3 4 4 5% 7% 51%	2156
	21st to end	Day	4 3 1 4 3 2 4 4 4 6% 66%	1980
October	1st to 10th	Day	6% 3 2 4 4 2 3 4 5% 7% 60%	1812
	11th to 20th	Day	4 3 1 2 3 2 4 3 3 4 73%	1800
	21st to end	Day	3 3 1 2 2 2 2 2 3 5% 77%	1980
November	1st to 10th	Day	3 2 1 2 2 2 2 3 3 6% 75%	1853
	11th to 20th	Day	1 2 1 3 3 2 3 3 5% 7% 72%	1710
	21st to end	Day	3 4 1 3 2 2 4 5% 5% 7% 65%	1710
December	1st to 10th	Day	2 3 1 2 3 2 4 4 6% 8% 66%	1710
	11th to 20th	Day	1 4 2 4 4 3 4 5% 6% 8% 59%	1936
	21st to end	Day	1 3 1 3 2 2 3 3 4 6% 72%	2890
January	1st to 10th	Night	1 2 2 3 3 2 4 5% 4 7% 66%	4097
	11th to 20th	Night	1 2 1 2 3 2 3 3 4 5% 73%	4110
	21st to end	Night	2 3 2 3 3 2 4 5% 8% 12% 55%	4521
February	1st to 10th	Night	1 2 1 3 3 2 2 3 5% 8% 69%	2333
	11th to 20th	Night	2 3 1 2 2 2 3 4 4 7% 70%	2218
	21st to end	Night	1 2 1 2 2 2 3 4 5% 8% 71%	1884
March	1st to 10th	Night	1 3 1 2 2 2 3 4 5% 9% 68%	2166
	11th to 20th	Night	3 4 2 2 3 2 3 3 6% 6% 66%	1980
	21st to end	Night	1 2 1 2 2 1 2 3 4 8% 74%	2091
April	1st to 10th	Night	2 2 1 2 2 2 3 4 5% 7% 71%	1800
	11th to 20th	Night	2 3 1 1 2 1 3 4 5% 7% 71%	1777
	21st to end	Night	2 2 1 2 2 3 3 5% 7% 72%	1800
May	1st to 10th	Night	2 2 1 2 3 2 2 3 5% 7% 71%	1800
	11th to 20th	Night	4 2 1 3 3 2 4 4 4 7% 67%	1770
	21st to end	Night	1 2 1 2 3 1 4 4 4 7% 72%	1699
June	1st to 10th	Night	3 2 2 4 4 2 5% 5% 8% 9% 56%	1440
	11th to 20th	Night	2 1 1 2 2 1 3 4 6% 7% 71%	1440
	21st to end	Night	6% 3 2 4 5% 3 6% 6% 5% 9% 51%	1440
July	1st to 10th	Night	7% 3 2 4 5% 4 4 5% 8% 11% 47%	1592
	11th to 20th	Night	3 2 2 3 5% 4 6% 8% 8% 12% 46%	1620
	21st to end	Night	4 3 1 4 5% 5% 6% 7% 9% 15% 40%	1773
August	1st to 10th	Night	4 5% 2 4 5% 4 6% 8% 9% 13% 40%	1778
	11th to 20th	Night	6% 3 1 3 4 3 6% 6% 9% 12% 46%	1778
	21st to end	Night	4 3 1 4 5% 3 5% 7% 8% 12% 48%	1980
September	1st to 10th	Night	7% 3 1 4 5% 3 5% 5% 7% 8% 51%	1800
	11th to 20th	Night	6% 3 2 3 4 2 4 4 5% 8% 59%	1802
	21st to end	Night	4 3 1 2 3 2 3 3 4 7% 68%	1980
October	1st to 10th	Night	4 3 1 3 3 2 3 4 5% 7% 64%	2144
	11th to 20th	Night	2 2 1 3 2 1 2 3 4 4 76%	2160
	21st to end	Night	3 2 1 2 2 1 2 3 4 5% 73%	2376
November	1st to 10th	Night	3 2 1 2 2 1 2 3 4 7% 72%	2220
	11th to 20th	Night	1 1 2 2 2 4 3 5% 6% 73%	2455
	21st to end	Night	2 5% 1 3 3 1 3 3 6% 7% 66%	2470
December	1st to 10th	Night	2 3 1 3 2 2 4 3 5% 9% 66%	2470
	11th to 20th	Night	1 3 2 3 4 2 4 5% 5% 8% 64%	3256
	21st to end	Night	1 3 2 3 3 2 3 3 5% 6% 69%	4805

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	16% 14% 4 15% 38% 12%	2859
	11th to 20th	Day	10% 9% 7% 22% 39% 13%	2860
	21st to end	Day	27% 13% 4 14% 28% 13%	3146
February	1st to 10th	Day	19% 6% 6% 19% 27% 24%	1844
	11th to 20th	Day	19% 7% 5% 18% 28% 23%	1859
	21st to end	Day	14% 8% 3 12% 32% 31%	1570
March	1st to 10th	Day	20% 6% 6% 16% 31% 21%	1951
	11th to 20th	Day	23% 7% 4 13% 29% 23%	1980
	21st to end	Day	16% 7% 5% 18% 36% 19%	2263
April	1st to 10th	Day	15% 5% 4 16% 37% 24%	2160
	11th to 20th	Day	18% 5% 4 14% 30% 29%	2134
	21st to end	Day	14% 6% 4 19% 36% 22%	2160
May	1st to 10th	Day	15% 5% 5% 14% 32% 29%	2160
	11th to 20th	Day	25% 7% 7% 15% 27% 19%	2128
	21st to end	Day	14% 6% 7% 19% 27% 27%	2567
June	1st to 10th	Day	17% 7% 13% 19% 24% 19%	2520
	11th to 20th	Day	14% 5% 5% 15% 25% 35%	2520
	21st to end	Day	30% 8% 11% 17% 20% 14%	2520
July	1st to 10th	Day	40% 12% 13% 14% 13% 8%	2297
	11th to 20th	Day	35% 13% 16% 20% 11% 4	2271
	21st to end	Day	39% 16% 21% 16% 6% 1	2404
August	1st to 10th	Day	42% 12% 16% 20% 8% 2	2145
	11th to 20th	Day	41% 11% 15% 18% 12% 3	2123
	21st to end	Day	37% 10% 15% 21% 14% 2	2376
September	1st to 10th	Day	38% 9% 10% 17% 19% 8%	2160
	11th to 20th	Day	32% 6% 8% 19% 25% 10%	2156
	21st to end	Day	20% 6% 7% 22% 31% 14%	1980
October	1st to 10th	Day	25% 7% 8% 17% 25% 18%	1812
	11th to 20th	Day	18% 4 3 14% 32% 30%	1800
	21st to end	Day	13% 4 4 22% 37% 19%	1980
November	1st to 10th	Day	13% 5% 3 20% 36% 21%	1853
	11th to 20th	Day	14% 6% 6% 21% 31% 22%	1710
	21st to end	Day	20% 7% 5% 18% 29% 21%	1710
December	1st to 10th	Day	17% 8% 5% 25% 31% 14%	1710
	11th to 20th	Day	21% 10% 8% 15% 31% 15%	1934
	21st to end	Day	15% 7% 7% 16% 28% 27%	2890
January	1st to 10th	Night	16% 12% 4 17% 34% 16%	4097
	11th to 20th	Night	13% 8% 5% 21% 39% 14%	4110
	21st to end	Night	22% 14% 5% 17% 28% 13%	4521
February	1st to 10th	Night	14% 7% 7% 20% 27% 25%	2333
	11th to 20th	Night	16% 8% 4 19% 29% 24%	2218
	21st to end	Night	13% 8% 4 16% 30% 29%	1884
March	1st to 10th	Night	16% 8% 6% 18% 30% 22%	2166
	11th to 20th	Night	20% 8% 4 17% 33% 18%	1980
	21st to end	Night	11% 8% 7% 19% 36% 20%	2091
April	1st to 10th	Night	14% 6% 4 16% 38% 22%	1800
	11th to 20th	Night	14% 6% 7% 15% 31% 27%	1777
	21st to end	Night	13% 6% 5% 19% 37% 19%	1800
May	1st to 10th	Night	15% 5% 4 12% 37% 27%	1800
	11th to 20th	Night	19% 5% 9% 20% 26% 20%	1771
	21st to end	Night	13% 4 7% 19% 26% 30%	1700
June	1st to 10th	Night	22% 8% 10% 18% 22% 20%	1440
	11th to 20th	Night	12% 5% 5% 20% 20% 39%	1440
	21st to end	Night	29% 8% 12% 16% 16% 18%	1440
July	1st to 10th	Night	29% 11% 17% 19% 18% 6%	1547
	11th to 20th	Night	24% 12% 18% 29% 13% 4	1566
	21st to end	Night	28% 13% 26% 22% 10% 1	1674
August	1st to 10th	Night	28% 12% 24% 26% 8% 2	1768
	11th to 20th	Night	27% 11% 19% 26% 13% 3	1778
	21st to end	Night	26% 11% 18% 26% 18% 2	1980
September	1st to 10th	Night	28% 8% 14% 20% 21% 9%	1800
	11th to 20th	Night	24% 7% 12% 20% 27% 11%	1802
	21st to end	Night	18% 5% 10% 22% 33% 12%	1980
October	1st to 10th	Night	21% 7% 9% 21% 25% 17%	2144
	11th to 20th	Night	14% 5% 4 14% 31% 32%	2160
	21st to end	Night	15% 5% 5% 18% 34% 23%	2376
November	1st to 10th	Night	13% 5% 5% 19% 35% 23%	2220
	11th to 20th	Night	12% 6% 5% 21% 33% 24%	2455
	21st to end	Night	19% 7% 6% 15% 33% 20%	2470
December	1st to 10th	Night	19% 7% 7% 22% 27% 18%	2470
	11th to 20th	Night	19% 9% 8% 17% 27% 19%	3257
	21st to end	Night	17% 9% 5% 16% 31% 23%	4805

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	15% 30% 31% 21% 3	270
	11th to 20th	Day	22% 22% 29% 21% 4 1	270
	21st to end	Day	15% 26% 32% 18% 9%	297
February	1st to 10th	Day	17% 33% 26% 19% 6%	270
	11th to 20th	Day	21% 30% 31% 13% 4	270
	21st to end	Day	32% 35% 19% 11% 4	225
March	1st to 10th	Day	18% 33% 33% 11% 5%	342
	11th to 20th	Day	19% 30% 31% 14% 6% 1	420
	21st to end	Day	23% 33% 32% 9% 3	462
April	1st to 10th	Day	14% 36% 35% 12% 3 1	420
	11th to 20th	Day	19% 38% 30% 11% 2	412
	21st to end	Day	15% 36% 35% 11% 3	420
May	1st to 10th	Day	7% 31% 45% 13% 3	423
	11th to 20th	Day	10% 22% 40% 20% 8%	448
	21st to end	Day	5% 23% 39% 24% 8% 1	618
June	1st to 10th	Day	4 9% 29% 37% 19% 2	630
	11th to 20th	Day	4 10% 29% 35% 20% 2	630
	21st to end	Day	8% 7% 21% 36% 25% 5%	630
July	1st to 10th	Day	5% 1 19% 43% 26% 6%	467
	11th to 20th	Day	5% 11% 36% 37% 11%	444
	21st to end	Day	6% 1 9% 34% 37% 13%	487
August	1st to 10th	Day	8% 2 10% 33% 38% 11%	447
	11th to 20th	Day	8% 3 14% 39% 28% 7%	437
	21st to end	Day	8% 2 13% 37% 31% 9%	495
September	1st to 10th	Day	8% 4 17% 40% 26% 6%	450
	11th to 20th	Day	6% 2 30% 37% 20% 5%	446
	21st to end	Day	4 7% 36% 27% 21% 4	270
October	1st to 10th	Day	11% 12% 32% 28% 14% 3	270
	11th to 20th	Day	11% 15% 31% 26% 14% 3	270
	21st to end	Day	14% 20% 28% 21% 13% 4	297
November	1st to 10th	Day	14% 27% 28% 19% 9% 3	270
	11th to 20th	Day	9% 20% 27% 26% 16% 3	270
	21st to end	Day	15% 31% 26% 19% 8% 1	270
December	1st to 10th	Day	19% 22% 30% 21% 9%	270
	11th to 20th	Day	14% 32% 26% 23% 5%	270
	21st to end	Day	26% 29% 26% 15% 5%	297
January	1st to 10th	Night	9% 18% 28% 30% 13% 2	760
	11th to 20th	Night	10% 21% 31% 27% 10% 2	760
	21st to end	Night	11% 20% 29% 28% 12% 1	836
February	1st to 10th	Night	10% 21% 30% 28% 9% 2	760
	11th to 20th	Night	10% 24% 37% 23% 5% 1	744
	21st to end	Night	14% 30% 33% 18% 4 1	628
March	1st to 10th	Night	14% 25% 27% 27% 7% 1	750
	11th to 20th	Night	11% 18% 29% 28% 13%	720
	21st to end	Night	10% 23% 35% 26% 6%	705
April	1st to 10th	Night	9% 26% 37% 22% 5%	540
	11th to 20th	Night	9% 28% 30% 25% 7%	533
	21st to end	Night	7% 26% 33% 27% 6%	540
May	1st to 10th	Night	4 18% 42% 31% 5%	540
	11th to 20th	Night	5% 14% 28% 34% 17% 2	531
	21st to end	Night	4 12% 36% 36% 12%	584
June	1st to 10th	Night	4 7% 27% 43% 18% 1	540
	11th to 20th	Night	3 6% 29% 45% 16% 1	540
	21st to end	Night	6% 4 17% 40% 30% 3	540
July	1st to 10th	Night	7% 2 12% 36% 39% 5%	525
	11th to 20th	Night	4 5% 33% 49% 9%	522
	21st to end	Night	4 1 8% 26% 49% 12%	591
August	1st to 10th	Night	3 1 4 26% 53% 12%	537
	11th to 20th	Night	4 2 9% 29% 45% 10%	534
	21st to end	Night	4 2 9% 25% 50% 11%	594
September	1st to 10th	Night	8% 1 8% 34% 44% 6%	540
	11th to 20th	Night	7% 1 14% 38% 37% 3	540
	21st to end	Night	6% 4 17% 40% 29% 4	540
October	1st to 10th	Night	5% 9% 21% 38% 24% 3	704
	11th to 20th	Night	5% 8% 28% 40% 16% 3	720
	21st to end	Night	9% 14% 21% 28% 22% 7%	792
November	1st to 10th	Night	6% 14% 23% 34% 19% 4	740
	11th to 20th	Night	5% 14% 27% 36% 15% 3	935
	21st to end	Night	11% 18% 25% 26% 17% 2	950
December	1st to 10th	Night	12% 18% 27% 31% 11% 2	950
	11th to 20th	Night	13% 22% 31% 27% 7% 1	950
	21st to end	Night	14% 20% 32% 25% 7% 1	1003

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