Arkansas Oklahoma Regional Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Arkansas Oklahoma Regional Star Party clear sky chart from 2005-11-06 to 2024-01-27.

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	15% 6% 3 5% 5% 3 4 4 5% 6% 44%	74698
	Night	14% 6% 2 4 4 2 4 4 5% 7% 49%	75357
Transparency	Day	39% 6% 11% 23% 17% 4	74422
	Night	35% 5% 11% 23% 20% 5%	75153
Seeing	Day	17% 13% 25% 25% 16% 4	14311
	Night	17% 13% 23% 30% 16% 2	24290

By Month

Percentage Cloud Cover SE (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	16% 8% 2 5% 4 2 3 4 4 4 49%	1707
	11th to 20th	Day	15% 6% 3 6% 5% 3 4 3 3 5% 48%	1710
	21st to end	Day	17% 8% 3 4 4 2 3 3 4 4 49%	1836
February	1st to 10th	Day	21% 9% 3 4 4 2 3 2 4 5% 43%	1620
	11th to 20th	Day	20% 7% 2 6% 5% 2 3 4 4 4 42%	1592
	21st to end	Day	22% 8% 4 6% 4 2 3 3 3 5% 39%	1613
March	1st to 10th	Day	19% 6% 3 4 4 2 4 4 5% 5% 44%	1980
	11th to 20th	Day	24% 7% 3 5% 5% 2 3 3 4 4 41%	1980
	21st to end	Day	22% 9% 4 6% 5% 2 3 3 4 6% 35%	2178
April	1st to 10th	Day	19% 6% 2 5% 4 3 4 5% 5% 6% 42%	2094
	11th to 20th	Day	21% 6% 2 5% 5% 2 4 5% 5% 5% 39%	2134
	21st to end	Day	24% 7% 3 6% 5% 2 4 3 4 5% 37%	2160
May	1st to 10th	Day	21% 7% 3 5% 5% 3 4 4 4 5% 39%	2286
	11th to 20th	Day	17% 5% 3 5% 6% 3 6% 5% 6% 6% 38%	2302
	21st to end	Day	13% 7% 3 6% 7% 4 6% 6% 6% 7% 35%	2531
June	1st to 10th	Day	11% 5% 3 5% 5% 4 6% 4 6% 8% 42%	2340
	11th to 20th	Day	8% 4 3 6% 6% 4 6% 6% 7% 9% 42%	2340
	21st to end	Day	7% 4 1 4 4 3 5% 6% 7% 9% 50%	2340
July	1st to 10th	Day	11% 5% 2 5% 6% 4 6% 6% 8% 11% 37%	2340
	11th to 20th	Day	6% 4 2 4 6% 3 6% 6% 7% 9% 47%	2340
	21st to end	Day	7% 4 2 5% 6% 3 7% 7% 8% 10% 41%	2546
August	1st to 10th	Day	8% 5% 2 4 5% 5% 6% 5% 8% 10% 41%	2328
	11th to 20th	Day	12% 5% 2 5% 5% 4 5% 6% 6% 8% 43%	2242
	21st to end	Day	8% 5% 2 5% 6% 4 5% 6% 6% 9% 47%	2376
September	1st to 10th	Day	12% 5% 2 4 4 3 4 4 5% 7% 50%	2160
	11th to 20th	Day	12% 4 1 5% 4 3 5% 6% 6% 9% 45%	2044
	21st to end	Day	9% 4 2 4 5% 3 5% 4 5% 6% 54%	1936
October	1st to 10th	Day	11% 5% 2 4 5% 2 4 4 3 6% 54%	1800
	11th to 20th	Day	15% 5% 2 4 4 2 2 3 4 4 55%	1800
	21st to end	Day	21% 6% 2 4 3 2 3 3 3 4 49%	1980
November	1st to 10th	Day	14% 6% 3 3 3 2 3 2 3 6% 56%	1858
	11th to 20th	Day	13% 6% 3 3 4 2 3 3 4 5% 55%	1900
	21st to end	Day	22% 6% 3 4 3 2 3 3 4 6% 46%	1600
December	1st to 10th	Day	17% 8% 2 3 4 2 4 3 4 5% 47%	1520
	11th to 20th	Day	16% 8% 3 5% 5% 3 3 3 4 5% 44%	2050
	21st to end	Day	19% 13% 5% 5% 4 2 4 4 4 5% 34%	3135
January	1st to 10th	Night	16% 6% 2 4 3 2 3 4 4 5% 49%	2458
	11th to 20th	Night	15% 8% 3 5% 3 2 3 3 4 5% 49%	2470
	21st to end	Night	17% 7% 2 3 4 2 2 3 3 5% 51%	2665
February	1st to 10th	Night	18% 8% 3 6% 4 2 4 3 4 6% 41%	2340
	11th to 20th	Night	17% 7% 4 4 4 3 3 3 4 7% 45%	2254
	21st to end	Night	20% 7% 2 5% 3 2 3 4 4 4 45%	1659
March	1st to 10th	Night	18% 6% 2 4 5% 3 4 4 5% 5% 44%	1980
	11th to 20th	Night	20% 7% 2 4 5% 2 4 4 4 6% 41%	1980
	21st to end	Night	20% 7% 3 6% 4 3 3 3 4 6% 41%	2178
April	1st to 10th	Night	16% 6% 2 5% 4 2 4 4 4 7% 47%	1864
	11th to 20th	Night	17% 6% 2 5% 3 3 3 3 5% 6% 47%	1775
	21st to end	Night	20% 4 3 5% 5% 2 4 4 5% 7% 42%	1800
May	1st to 10th	Night	17% 6% 2 4 4 2 4 4 5% 6% 46%	1670
	11th to 20th	Night	17% 4 1 3 4 2 3 4 7% 7% 47%	1593
	21st to end	Night	12% 6% 2 5% 5% 3 5% 5% 8% 9% 41%	1745
June	1st to 10th	Night	7% 4 1 3 3 2 5% 5% 6% 10% 55%	1620
	11th to 20th	Night	6% 3 1 2 3 3 4 5% 6% 11% 56%	1620
	21st to end	Night	7% 2 1 2 4 2 3 4 6% 8% 61%	1620
July	1st to 10th	Night	7% 2 2 3 4 2 4 6% 8% 10% 51%	1620
	11th to 20th	Night	3 3 2 4 4 2 3 5% 6% 11% 58%	1620
	21st to end	Night	5% 3 2 4 5% 3 4 5% 6% 11% 52%	1772
August	1st to 10th	Night	4 3 2 4 5% 2 6% 5% 6% 10% 52%	1611
	11th to 20th	Night	7% 4 2 5% 4 3 4 5% 6% 10% 49%	1658
	21st to end	Night	6% 3 2 4 4 2 4 5% 6% 9% 54%	1980
September	1st to 10th	Night	8% 4 1 4 4 2 3 5% 5% 8% 56%	1800
	11th to 20th	Night	10% 5% 2 4 4 2 4 5% 5% 6% 52%	1912
	21st to end	Night	9% 4 2 3 3 2 4 5% 5% 6% 58%	2004
October	1st to 10th	Night	8% 3 2 3 3 3 4 5% 5% 7% 58%	2160
	11th to 20th	Night	15% 4 2 3 3 2 3 3 3 5% 57%	2160
	21st to end	Night	20% 6% 1 4 3 2 3 3 3 5% 51%	2376
November	1st to 10th	Night	14% 5% 2 4 3 2 3 3 3 4 58%	2220
	11th to 20th	Night	14% 5% 2 3 3 2 3 3 4 6% 55%	2280
	21st to end	Night	20% 5% 3 4 3 2 3 3 4 5% 49%	2569
December	1st to 10th	Night	17% 7% 2 4 4 3 3 3 4 6% 48%	2660
	11th to 20th	Night	17% 8% 3 6% 4 2 3 3 4 4 45%	3132
	21st to end	Night	21% 10% 5% 7% 5% 2 4 3 3 4 37%	4532

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	40% 3 7% 24% 20% 5%	1708
	11th to 20th	Day	40% 4 8% 25% 20% 2	1710
	21st to end	Day	40% 3 7% 28% 18% 4	1836
February	1st to 10th	Day	46% 4 10% 20% 16% 4	1620
	11th to 20th	Day	46% 3 8% 22% 17% 4	1601
	21st to end	Day	48% 4 8% 16% 17% 8%	1613
March	1st to 10th	Day	41% 5% 7% 18% 19% 9%	1980
	11th to 20th	Day	48% 3 8% 22% 13% 5%	1980
	21st to end	Day	51% 6% 9% 19% 13% 2	2178
April	1st to 10th	Day	42% 6% 10% 20% 20% 2	2094
	11th to 20th	Day	46% 5% 10% 19% 16% 4	2134
	21st to end	Day	49% 5% 8% 21% 15% 2	2160
May	1st to 10th	Day	48% 6% 9% 20% 15% 1	2286
	11th to 20th	Day	44% 9% 13% 22% 12% 1	2306
	21st to end	Day	46% 9% 13% 19% 12%	2531
June	1st to 10th	Day	38% 8% 14% 25% 13% 1	2340
	11th to 20th	Day	36% 10% 14% 24% 15% 2	2340
	21st to end	Day	27% 9% 14% 29% 17% 4	2340
July	1st to 10th	Day	36% 10% 17% 24% 11% 1	2276
	11th to 20th	Day	28% 8% 16% 30% 16% 2	2271
	21st to end	Day	32% 12% 17% 28% 10% 1	2405
August	1st to 10th	Day	34% 10% 19% 24% 12% 1	2314
	11th to 20th	Day	36% 9% 13% 25% 16% 1	2242
	21st to end	Day	33% 8% 16% 24% 15% 4	2376
September	1st to 10th	Day	32% 7% 12% 25% 17% 8%	2160
	11th to 20th	Day	33% 7% 12% 22% 21% 4	2044
	21st to end	Day	30% 6% 9% 21% 28% 5%	1936
October	1st to 10th	Day	32% 5% 12% 20% 24% 8%	1800
	11th to 20th	Day	33% 4 6% 23% 25% 9%	1800
	21st to end	Day	40% 4 8% 22% 18% 8%	1980
November	1st to 10th	Day	32% 4 8% 26% 21% 9%	1858
	11th to 20th	Day	33% 4 7% 24% 23% 9%	1900
	21st to end	Day	41% 4 8% 19% 24% 5%	1600
December	1st to 10th	Day	40% 4 8% 24% 19% 4	1520
	11th to 20th	Day	44% 4 6% 17% 26% 3	2048
	21st to end	Day	51% 6% 8% 18% 14% 3	3135
January	1st to 10th	Night	37% 4 10% 21% 23% 5%	2458
	11th to 20th	Night	38% 3 10% 23% 22% 3	2470
	21st to end	Night	36% 4 7% 25% 23% 6%	2665
February	1st to 10th	Night	45% 4 9% 22% 16% 4	2340
	11th to 20th	Night	41% 4 7% 25% 18% 5%	2255
	21st to end	Night	42% 4 8% 18% 20% 9%	1659
March	1st to 10th	Night	41% 5% 8% 17% 21% 9%	1980
	11th to 20th	Night	44% 5% 11% 19% 17% 5%	1980
	21st to end	Night	46% 5% 8% 24% 14% 3	2178
April	1st to 10th	Night	38% 5% 9% 22% 21% 6%	1864
	11th to 20th	Night	38% 5% 8% 23% 19% 7%	1775
	21st to end	Night	41% 6% 10% 23% 18% 2	1800
May	1st to 10th	Night	39% 6% 13% 20% 19% 3	1670
	11th to 20th	Night	35% 8% 16% 25% 15% 2	1594
	21st to end	Night	37% 9% 17% 23% 13% 1	1746
June	1st to 10th	Night	24% 8% 16% 31% 19% 2	1620
	11th to 20th	Night	22% 7% 15% 34% 20% 2	1620
	21st to end	Night	21% 7% 16% 28% 23% 6%	1620
July	1st to 10th	Night	25% 9% 21% 26% 18% 1	1575
	11th to 20th	Night	19% 8% 17% 30% 23% 2	1566
	21st to end	Night	25% 7% 17% 34% 15% 1	1673
August	1st to 10th	Night	25% 8% 19% 33% 15%	1601
	11th to 20th	Night	29% 7% 16% 24% 22% 2	1658
	21st to end	Night	25% 8% 16% 27% 20% 4	1980
September	1st to 10th	Night	26% 6% 11% 30% 18% 8%	1800
	11th to 20th	Night	31% 7% 11% 21% 23% 6%	1912
	21st to end	Night	27% 6% 8% 25% 28% 7%	2004
October	1st to 10th	Night	24% 7% 14% 23% 23% 10%	2160
	11th to 20th	Night	31% 4 6% 18% 30% 10%	2160
	21st to end	Night	38% 4 7% 20% 22% 10%	2376
November	1st to 10th	Night	31% 4 8% 23% 25% 9%	2220
	11th to 20th	Night	31% 4 8% 24% 25% 8%	2280
	21st to end	Night	39% 3 7% 21% 25% 6%	2569
December	1st to 10th	Night	39% 4 9% 21% 22% 6%	2660
	11th to 20th	Night	43% 4 7% 19% 20% 7%	3133
	21st to end	Night	49% 7% 8% 18% 15% 4	4532

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	30% 23% 30% 13% 4	270
	11th to 20th	Day	29% 27% 30% 11% 1	270
	21st to end	Day	23% 30% 29% 13% 4	282
February	1st to 10th	Day	30% 26% 32% 8% 3	240
	11th to 20th	Day	33% 31% 28% 6% 2	240
	21st to end	Day	40% 24% 28% 5% 3	198
March	1st to 10th	Day	29% 26% 31% 10% 3	240
	11th to 20th	Day	33% 23% 34% 9% 2	240
	21st to end	Day	32% 31% 27% 8% 2	264
April	1st to 10th	Day	26% 26% 27% 14% 7% 1	354
	11th to 20th	Day	29% 20% 29% 16% 5%	412
	21st to end	Day	27% 20% 31% 15% 6%	420
May	1st to 10th	Day	22% 18% 34% 19% 5% 1	549
	11th to 20th	Day	19% 12% 29% 26% 11% 3	625
	21st to end	Day	13% 10% 34% 27% 13% 3	679
June	1st to 10th	Day	10% 7% 21% 36% 21% 4	630
	11th to 20th	Day	7% 6% 23% 38% 22% 3	630
	21st to end	Day	6% 4 30% 35% 21% 5%	630
July	1st to 10th	Day	10% 3 15% 35% 28% 9%	621
	11th to 20th	Day	6% 3 18% 33% 31% 9%	618
	21st to end	Day	7% 2 11% 36% 34% 10%	684
August	1st to 10th	Day	9% 4 15% 39% 28% 5%	626
	11th to 20th	Day	14% 2 13% 36% 28% 7%	556
	21st to end	Day	8% 3 12% 31% 34% 12%	495
September	1st to 10th	Day	11% 3 13% 31% 34% 8%	450
	11th to 20th	Day	7% 3 21% 39% 25% 6%	334
	21st to end	Day	11% 8% 23% 36% 19% 2	270
October	1st to 10th	Day	10% 12% 31% 27% 17% 2	270
	11th to 20th	Day	17% 17% 39% 21% 4 1	270
	21st to end	Day	29% 19% 32% 16% 4	297
November	1st to 10th	Day	17% 18% 33% 21% 10% 1	270
	11th to 20th	Day	21% 22% 33% 17% 6% 1	270
	21st to end	Day	29% 22% 23% 19% 6% 1	270
December	1st to 10th	Day	23% 25% 28% 16% 7% 1	270
	11th to 20th	Day	27% 22% 30% 16% 5%	270
	21st to end	Day	26% 25% 35% 12% 2	297
January	1st to 10th	Night	21% 20% 28% 26% 5%	950
	11th to 20th	Night	23% 21% 27% 25% 4	950
	21st to end	Night	20% 20% 28% 27% 4	1025
February	1st to 10th	Night	23% 21% 27% 25% 4	900
	11th to 20th	Night	23% 23% 32% 20% 3	860
	21st to end	Night	28% 20% 30% 20% 2	475
March	1st to 10th	Night	22% 16% 28% 30% 4	540
	11th to 20th	Night	23% 15% 27% 30% 5%	540
	21st to end	Night	23% 18% 31% 21% 6% 1	594
April	1st to 10th	Night	20% 19% 30% 25% 7%	540
	11th to 20th	Night	18% 18% 29% 26% 8% 1	533
	21st to end	Night	20% 15% 33% 21% 10%	540
May	1st to 10th	Night	19% 9% 31% 31% 11%	540
	11th to 20th	Night	17% 9% 24% 31% 18% 1	531
	21st to end	Night	13% 4 29% 30% 20% 4	584
June	1st to 10th	Night	8% 4 12% 40% 33% 3	540
	11th to 20th	Night	6% 2 21% 40% 28% 3	540
	21st to end	Night	6% 3 16% 37% 33% 5%	540
July	1st to 10th	Night	7% 2 8% 31% 45% 6%	525
	11th to 20th	Night	4 2 10% 34% 40% 9%	522
	21st to end	Night	4 2 7% 33% 45% 9%	591
August	1st to 10th	Night	4 2 9% 40% 37% 7%	537
	11th to 20th	Night	8% 1 12% 36% 38% 6%	534
	21st to end	Night	7% 2 9% 36% 41% 6%	594
September	1st to 10th	Night	8% 3 14% 32% 40% 3	540
	11th to 20th	Night	12% 3 11% 39% 31% 4	540
	21st to end	Night	11% 5% 18% 34% 29% 4	564
October	1st to 10th	Night	10% 6% 23% 34% 25% 3	720
	11th to 20th	Night	16% 13% 28% 29% 13%	720
	21st to end	Night	22% 15% 23% 25% 14% 2	792
November	1st to 10th	Night	15% 13% 27% 30% 14% 1	740
	11th to 20th	Night	17% 15% 29% 31% 8%	760
	21st to end	Night	24% 16% 23% 27% 10%	944
December	1st to 10th	Night	21% 16% 28% 28% 7%	950
	11th to 20th	Night	23% 17% 25% 30% 5%	950
	21st to end	Night	23% 19% 24% 28% 5%	1045

Page generated at 2024-01-24 08:37:27. Version ac07

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