South Cushing
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the South Cushing clear sky chart from 2005-11-06 to 2025-10-19.

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	19% 8% 2 6% 4 4 4 3 5% 7% 38%	125814
	Night	19% 9% 3 6% 4 4 4 3 5% 6% 37%	123890
Transparency	Day	45% 7% 12% 21% 13% 2	129336
	Night	46% 6% 12% 21% 14% 2	128456
Seeing	Day	21% 12% 31% 25% 10% 2	16721
	Night	23% 12% 29% 25% 10% 1	25243

By Month

Percentage Cloud Cover NE (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	15% 7% 3 7% 6% 4 5% 4 5% 7% 38%	3597
	11th to 20th	Day	15% 9% 3 6% 4 3 3 3 4 6% 45%	3570
	21st to end	Day	13% 11% 3 6% 4 3 4 2 4 5% 46%	4024
February	1st to 10th	Day	17% 10% 3 6% 5% 4 4 4 5% 6% 36%	1800
	11th to 20th	Day	14% 9% 3 7% 4 4 4 4 6% 7% 39%	1903
	21st to end	Day	15% 10% 2 7% 5% 4 4 4 6% 5% 37%	1650
March	1st to 10th	Day	24% 10% 3 6% 4 4 5% 3 4 5% 32%	4476
	11th to 20th	Day	20% 11% 3 6% 4 3 3 3 4 5% 37%	4973
	21st to end	Day	29% 7% 2 5% 4 4 4 3 5% 5% 33%	5482
April	1st to 10th	Day	20% 10% 3 5% 4 4 4 3 5% 6% 35%	2400
	11th to 20th	Day	19% 7% 2 5% 4 4 4 3 5% 6% 40%	2514
	21st to end	Day	22% 7% 3 6% 5% 4 4 3 5% 6% 37%	2600
May	1st to 10th	Day	32% 11% 3 7% 4 3 4 3 5% 5% 25%	5886
	11th to 20th	Day	20% 10% 3 8% 4 4 5% 3 5% 6% 32%	5861
	21st to end	Day	22% 8% 2 6% 4 4 4 4 5% 8% 33%	6894
June	1st to 10th	Day	21% 8% 2 7% 5% 4 4 4 5% 7% 33%	2935
	11th to 20th	Day	19% 7% 2 5% 4 4 4 4 5% 7% 39%	3000
	21st to end	Day	23% 7% 3 6% 4 4 4 3 5% 7% 32%	2913
July	1st to 10th	Day	20% 8% 3 7% 5% 4 5% 4 6% 8% 31%	6360
	11th to 20th	Day	17% 11% 2 5% 3 3 4 3 6% 9% 36%	6360
	21st to end	Day	16% 6% 2 5% 3 3 4 3 5% 8% 44%	6837
August	1st to 10th	Day	17% 8% 3 6% 4 4 4 3 6% 8% 37%	4235
	11th to 20th	Day	18% 8% 2 6% 4 5% 4 4 5% 7% 38%	4175
	21st to end	Day	9% 5% 2 5% 4 4 4 4 6% 9% 49%	4578
September	1st to 10th	Day	11% 7% 1 5% 4 3 3 4 5% 8% 48%	2316
	11th to 20th	Day	12% 5% 2 5% 3 3 3 3 5% 7% 53%	2200
	21st to end	Day	18% 7% 2 4 3 4 4 3 4 7% 45%	2200
October	1st to 10th	Day	18% 7% 2 6% 4 3 4 4 4 6% 43%	2173
	11th to 20th	Day	19% 6% 2 6% 4 3 4 3 4 7% 43%	1950
	21st to end	Day	22% 8% 2 5% 4 4 3 3 4 6% 40%	1881
November	1st to 10th	Day	15% 7% 2 6% 4 3 4 2 5% 6% 46%	1761
	11th to 20th	Day	20% 6% 1 4 3 3 3 3 4 7% 46%	1800
	21st to end	Day	21% 8% 2 6% 3 3 3 2 4 6% 43%	1671
December	1st to 10th	Day	19% 8% 2 4 3 3 3 3 4 6% 45%	2423
	11th to 20th	Day	20% 7% 2 5% 3 3 2 3 3 5% 47%	2618
	21st to end	Day	21% 12% 3 6% 4 4 4 3 5% 5% 35%	3798
January	1st to 10th	Night	12% 9% 3 7% 4 4 4 4 5% 7% 41%	6349
	11th to 20th	Night	14% 11% 5% 9% 5% 4 4 4 5% 6% 35%	6315
	21st to end	Night	14% 11% 3 7% 4 4 4 3 5% 5% 41%	6932
February	1st to 10th	Night	18% 9% 3 6% 5% 5% 4 4 6% 5% 36%	2600
	11th to 20th	Night	14% 9% 3 7% 5% 5% 4 3 4 6% 39%	2379
	21st to end	Night	15% 9% 4 7% 5% 3 4 2 4 6% 41%	1980
March	1st to 10th	Night	27% 10% 2 6% 4 4 3 3 4 4 32%	5364
	11th to 20th	Night	17% 10% 3 6% 5% 5% 5% 4 5% 7% 33%	4984
	21st to end	Night	26% 8% 3 5% 4 3 4 3 6% 6% 32%	5434
April	1st to 10th	Night	23% 10% 2 6% 5% 3 4 3 4 6% 35%	2000
	11th to 20th	Night	20% 7% 3 6% 4 4 5% 3 5% 7% 36%	1833
	21st to end	Night	24% 9% 3 6% 3 4 4 3 4 7% 35%	1800
May	1st to 10th	Night	31% 9% 3 8% 4 4 4 3 5% 5% 24%	4054
	11th to 20th	Night	21% 10% 2 7% 6% 5% 5% 4 5% 6% 28%	4033
	21st to end	Night	18% 10% 3 8% 4 4 5% 4 5% 7% 32%	4021
June	1st to 10th	Night	23% 7% 2 7% 4 5% 5% 4 5% 8% 30%	1460
	11th to 20th	Night	18% 8% 3 6% 4 3 5% 4 5% 8% 37%	1400
	21st to end	Night	24% 11% 2 5% 5% 4 4 4 5% 7% 30%	1477
July	1st to 10th	Night	17% 10% 3 8% 5% 4 5% 3 6% 9% 30%	3600
	11th to 20th	Night	17% 14% 2 7% 5% 4 4 4 5% 8% 31%	3600
	21st to end	Night	11% 7% 2 5% 4 4 5% 4 6% 10% 42%	3967
August	1st to 10th	Night	23% 9% 3 8% 4 4 4 4 5% 6% 30%	2915
	11th to 20th	Night	16% 9% 3 8% 5% 5% 5% 3 5% 8% 33%	2872
	21st to end	Night	9% 5% 2 5% 4 4 4 4 5% 8% 49%	3316
September	1st to 10th	Night	13% 5% 2 5% 3 4 4 4 5% 6% 49%	2083
	11th to 20th	Night	15% 7% 2 4 3 2 3 3 4 6% 52%	2200
	21st to end	Night	17% 5% 2 5% 4 4 4 3 5% 6% 46%	2200
October	1st to 10th	Night	19% 6% 2 5% 4 3 4 3 5% 7% 42%	2225
	11th to 20th	Night	17% 6% 2 6% 3 4 4 4 5% 6% 44%	2405
	21st to end	Night	23% 8% 2 5% 4 3 3 3 4 7% 38%	2717
November	1st to 10th	Night	17% 6% 2 6% 4 3 3 3 5% 6% 45%	2537
	11th to 20th	Night	18% 6% 2 5% 4 3 4 4 5% 5% 45%	2600
	21st to end	Night	18% 8% 2 5% 4 4 3 4 6% 6% 41%	2725
December	1st to 10th	Night	18% 10% 2 5% 3 4 4 3 4 7% 40%	4763
	11th to 20th	Night	24% 7% 2 4 3 2 3 3 4 5% 44%	5591
	21st to end	Night	23% 11% 3 6% 3 3 3 2 3 5% 38%	7159

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	45% 5% 12% 26% 11%	3598
	11th to 20th	Day	41% 5% 14% 25% 13% 2	3600
	21st to end	Day	42% 5% 9% 20% 17% 6%	4024
February	1st to 10th	Day	48% 6% 13% 19% 13% 3	1800
	11th to 20th	Day	44% 6% 15% 19% 13% 3	1912
	21st to end	Day	46% 6% 10% 21% 13% 4	1650
March	1st to 10th	Day	52% 6% 10% 11% 14% 8%	4479
	11th to 20th	Day	48% 5% 14% 20% 10% 2	4973
	21st to end	Day	52% 4 6% 17% 16% 5%	5482
April	1st to 10th	Day	49% 5% 9% 18% 15% 3	2400
	11th to 20th	Day	43% 6% 10% 23% 15% 3	2514
	21st to end	Day	49% 5% 8% 19% 16% 3	2600
May	1st to 10th	Day	59% 9% 10% 15% 6% 1	5897
	11th to 20th	Day	51% 8% 12% 19% 8% 2	5865
	21st to end	Day	47% 8% 14% 19% 11% 1	6894
June	1st to 10th	Day	50% 7% 13% 21% 10%	2935
	11th to 20th	Day	43% 7% 12% 21% 15% 2	3000
	21st to end	Day	50% 8% 11% 19% 11% 1	2913
July	1st to 10th	Day	51% 7% 13% 19% 10%	6290
	11th to 20th	Day	44% 9% 17% 21% 9% 1	6285
	21st to end	Day	37% 7% 14% 27% 14% 1	6640
August	1st to 10th	Day	45% 7% 15% 25% 8%	4222
	11th to 20th	Day	43% 8% 19% 21% 9%	4214
	21st to end	Day	29% 9% 16% 27% 19% 1	4578
September	1st to 10th	Day	33% 7% 13% 28% 18% 1	2316
	11th to 20th	Day	33% 5% 12% 26% 22% 2	2200
	21st to end	Day	41% 5% 9% 27% 17% 1	2200
October	1st to 10th	Day	43% 7% 14% 21% 13% 1	3537
	11th to 20th	Day	31% 5% 10% 32% 22% 1	3166
	21st to end	Day	35% 5% 13% 25% 19% 4	3081
November	1st to 10th	Day	39% 6% 13% 25% 15% 2	1761
	11th to 20th	Day	40% 4 11% 21% 20% 3	1800
	21st to end	Day	45% 4 18% 22% 11% 1	1671
December	1st to 10th	Day	40% 5% 16% 27% 11% 1	2423
	11th to 20th	Day	41% 4 13% 18% 15% 8%	2618
	21st to end	Day	52% 6% 9% 17% 13% 3	3798
January	1st to 10th	Night	41% 5% 13% 29% 11% 1	6349
	11th to 20th	Night	50% 6% 13% 19% 10% 2	6360
	21st to end	Night	45% 5% 10% 20% 16% 5%	6932
February	1st to 10th	Night	50% 6% 12% 18% 12% 3	2600
	11th to 20th	Night	47% 5% 10% 20% 15% 3	2381
	21st to end	Night	45% 5% 10% 23% 13% 4	1980
March	1st to 10th	Night	56% 3 7% 13% 13% 8%	5374
	11th to 20th	Night	47% 7% 18% 19% 8% 2	4985
	21st to end	Night	52% 4 7% 15% 18% 4	5434
April	1st to 10th	Night	51% 4 8% 17% 16% 4	2000
	11th to 20th	Night	46% 6% 10% 21% 16% 2	1833
	21st to end	Night	51% 4 11% 17% 14% 3	1800
May	1st to 10th	Night	59% 8% 13% 12% 7% 1	4060
	11th to 20th	Night	53% 8% 11% 18% 8% 1	4034
	21st to end	Night	50% 9% 12% 20% 9% 1	4022
June	1st to 10th	Night	52% 7% 11% 20% 9% 1	1460
	11th to 20th	Night	45% 7% 14% 19% 14% 1	1400
	21st to end	Night	52% 7% 9% 19% 11% 1	1477
July	1st to 10th	Night	50% 7% 12% 20% 11%	3560
	11th to 20th	Night	50% 7% 13% 19% 10%	3552
	21st to end	Night	37% 7% 18% 26% 11% 1	3850
August	1st to 10th	Night	54% 7% 12% 19% 7% 1	2903
	11th to 20th	Night	47% 8% 15% 20% 9%	2899
	21st to end	Night	31% 8% 14% 27% 21% 1	3316
September	1st to 10th	Night	34% 6% 13% 28% 17% 1	2083
	11th to 20th	Night	36% 4 11% 27% 21% 2	2200
	21st to end	Night	38% 6% 9% 28% 16% 2	2200
October	1st to 10th	Night	39% 6% 14% 23% 16% 1	3641
	11th to 20th	Night	30% 5% 11% 29% 25% 1	3928
	21st to end	Night	38% 5% 10% 28% 17% 3	4467
November	1st to 10th	Night	40% 6% 12% 25% 15% 2	2537
	11th to 20th	Night	41% 5% 11% 23% 17% 3	2600
	21st to end	Night	44% 6% 16% 20% 13% 2	2725
December	1st to 10th	Night	45% 4 10% 28% 11%	4763
	11th to 20th	Night	44% 4 13% 19% 17% 3	5592
	21st to end	Night	50% 5% 10% 17% 17% 1	7159

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	24% 23% 34% 15% 5%	200
	11th to 20th	Day	26% 21% 29% 21% 3 1	200
	21st to end	Day	19% 18% 38% 21% 4	245
February	1st to 10th	Day	24% 24% 33% 17% 2	400
	11th to 20th	Day	23% 22% 40% 14% 2	473
	21st to end	Day	21% 18% 37% 18% 5%	414
March	1st to 10th	Day	22% 21% 36% 18% 3	500
	11th to 20th	Day	20% 20% 38% 18% 4	500
	21st to end	Day	27% 19% 31% 15% 6% 2	550
April	1st to 10th	Day	26% 19% 35% 15% 4 1	500
	11th to 20th	Day	24% 17% 35% 18% 5% 1	492
	21st to end	Day	26% 11% 36% 21% 6% 1	500
May	1st to 10th	Day	27% 13% 33% 20% 5% 1	503
	11th to 20th	Day	20% 8% 36% 27% 9% 1	527
	21st to end	Day	22% 10% 35% 25% 7% 1	573
June	1st to 10th	Day	23% 5% 31% 29% 10% 2	665
	11th to 20th	Day	20% 7% 31% 26% 14% 2	730
	21st to end	Day	22% 5% 27% 31% 13% 2	643
July	1st to 10th	Day	20% 5% 26% 34% 13% 2	525
	11th to 20th	Day	17% 5% 23% 38% 14% 3	524
	21st to end	Day	14% 3 25% 40% 15% 3	576
August	1st to 10th	Day	13% 4 24% 39% 18% 3	526
	11th to 20th	Day	15% 4 22% 35% 17% 7%	519
	21st to end	Day	13% 5% 26% 36% 16% 4	583
September	1st to 10th	Day	14% 5% 27% 33% 18% 3	530
	11th to 20th	Day	14% 8% 24% 32% 16% 6%	530
	21st to end	Day	18% 7% 29% 29% 13% 4	530
October	1st to 10th	Day	20% 11% 22% 29% 15% 3	514
	11th to 20th	Day	18% 12% 32% 25% 11% 2	414
	21st to end	Day	29% 10% 28% 27% 5%	429
November	1st to 10th	Day	16% 20% 30% 25% 6% 2	395
	11th to 20th	Day	24% 17% 33% 21% 5% 1	400
	21st to end	Day	25% 21% 30% 18% 6%	400
December	1st to 10th	Day	24% 15% 38% 15% 8%	291
	11th to 20th	Day	28% 21% 35% 12% 5% 1	200
	21st to end	Day	26% 20% 33% 15% 5%	220
January	1st to 10th	Night	22% 20% 36% 19% 3	800
	11th to 20th	Night	27% 20% 34% 15% 4	800
	21st to end	Night	20% 22% 35% 18% 4	880
February	1st to 10th	Night	25% 20% 33% 19% 4	800
	11th to 20th	Night	20% 22% 38% 17% 2	783
	21st to end	Night	21% 15% 38% 21% 5%	660
March	1st to 10th	Night	26% 18% 34% 21% 2	800
	11th to 20th	Night	21% 16% 32% 22% 8%	800
	21st to end	Night	24% 13% 34% 22% 6% 1	880
April	1st to 10th	Night	29% 13% 33% 20% 4 1	800
	11th to 20th	Night	23% 9% 34% 26% 7%	649
	21st to end	Night	29% 10% 27% 25% 8% 1	600
May	1st to 10th	Night	27% 4 29% 28% 11% 2	600
	11th to 20th	Night	26% 4 30% 30% 9% 1	592
	21st to end	Night	25% 4 24% 34% 13% 1	476
June	1st to 10th	Night	26% 4 21% 32% 15% 2	400
	11th to 20th	Night	20% 5% 19% 39% 17% 2	400
	21st to end	Night	30% 4 17% 37% 13%	400
July	1st to 10th	Night	22% 4 14% 41% 19% 1	390
	11th to 20th	Night	21% 2 18% 36% 20% 2	388
	21st to end	Night	17% 3 17% 40% 22% 1	454
August	1st to 10th	Night	18% 3 16% 42% 21% 1	598
	11th to 20th	Night	16% 3 16% 41% 22% 2	592
	21st to end	Night	15% 3 18% 38% 23% 3	714
September	1st to 10th	Night	14% 3 23% 35% 23% 2	800
	11th to 20th	Night	19% 5% 22% 27% 22% 5%	800
	21st to end	Night	19% 5% 24% 31% 19% 3	800
October	1st to 10th	Night	22% 7% 22% 31% 17% 2	800
	11th to 20th	Night	19% 11% 29% 27% 11% 2	793
	21st to end	Night	27% 13% 29% 24% 6%	836
November	1st to 10th	Night	21% 12% 34% 24% 8% 2	780
	11th to 20th	Night	21% 17% 35% 20% 6% 1	800
	21st to end	Night	22% 22% 30% 19% 6%	863
December	1st to 10th	Night	27% 15% 38% 14% 6%	900
	11th to 20th	Night	26% 21% 33% 17% 3	900
	21st to end	Night	28% 16% 35% 17% 4	915

Page generated at 2025-10-16 01:50:29. Version ac07

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