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 2024-08-30.

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% 7% 2 5% 4 4 4 3 5% 6% 44%	95180
	Night	15% 6% 2 5% 3 3 3 3 5% 6% 48%	93908
Transparency	Day	40% 6% 11% 23% 17% 4	94954
	Night	36% 5% 11% 23% 19% 5%	93740
Seeing	Day	18% 13% 25% 25% 15% 4	15214
	Night	17% 13% 23% 30% 16% 2	24987

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	15% 11% 3 5% 3 3 3 3 4 4 46%	2847
	11th to 20th	Day	11% 6% 3 7% 3 3 4 3 3 4 52%	2850
	21st to end	Day	24% 7% 2 4 3 2 3 2 4 4 46%	3135
February	1st to 10th	Day	21% 10% 3 5% 4 3 3 2 4 4 42%	1710
	11th to 20th	Day	19% 8% 2 6% 4 3 3 3 5% 5% 43%	1683
	21st to end	Day	21% 9% 3 7% 3 3 3 3 4 5% 40%	1711
March	1st to 10th	Day	23% 8% 3 5% 3 3 3 3 4 4 42%	3436
	11th to 20th	Day	17% 5% 2 5% 4 3 4 3 5% 6% 47%	3480
	21st to end	Day	20% 9% 3 7% 4 3 3 3 4 6% 38%	3814
April	1st to 10th	Day	19% 6% 2 5% 4 3 4 3 5% 5% 43%	2211
	11th to 20th	Day	21% 6% 2 6% 5% 3 4 4 5% 5% 39%	2254
	21st to end	Day	25% 8% 2 6% 4 3 4 3 4 5% 37%	2280
May	1st to 10th	Day	25% 8% 3 6% 5% 4 4 3 4 4 34%	4001
	11th to 20th	Day	16% 5% 2 6% 5% 4 5% 4 6% 6% 39%	4082
	21st to end	Day	20% 7% 2 7% 5% 5% 5% 4 5% 6% 34%	4477
June	1st to 10th	Day	11% 6% 2 6% 5% 5% 5% 4 6% 8% 42%	2470
	11th to 20th	Day	8% 5% 2 7% 5% 4 6% 5% 7% 9% 42%	2470
	21st to end	Day	7% 4 1 4 4 4 6% 5% 7% 9% 50%	2470
July	1st to 10th	Day	11% 6% 2 5% 4 4 5% 4 7% 10% 43%	4120
	11th to 20th	Day	5% 4 2 4 4 4 5% 4 6% 9% 51%	4120
	21st to end	Day	9% 6% 2 7% 6% 6% 7% 6% 9% 9% 34%	4465
August	1st to 10th	Day	8% 5% 2 5% 4 6% 5% 4 7% 10% 43%	2458
	11th to 20th	Day	12% 5% 2 6% 4 5% 5% 4 6% 8% 42%	2368
	21st to end	Day	7% 5% 2 5% 5% 5% 5% 4 6% 9% 47%	2485
September	1st to 10th	Day	12% 6% 2 5% 3 4 3 3 6% 7% 50%	2160
	11th to 20th	Day	12% 4 1 5% 4 4 5% 5% 6% 9% 45%	2044
	21st to end	Day	9% 4 2 5% 5% 4 5% 3 5% 6% 54%	1936
October	1st to 10th	Day	11% 5% 1 5% 4 3 4 3 4 6% 54%	1800
	11th to 20th	Day	15% 5% 2 5% 3 2 2 2 4 4 55%	1800
	21st to end	Day	21% 6% 2 4 2 3 2 2 3 4 49%	1980
November	1st to 10th	Day	13% 6% 2 3 3 3 3 2 4 6% 56%	1858
	11th to 20th	Day	13% 7% 2 4 3 2 3 3 4 5% 55%	1900
	21st to end	Day	22% 7% 2 5% 2 3 3 3 4 6% 46%	1600
December	1st to 10th	Day	17% 8% 2 4 4 3 3 3 4 5% 46%	1520
	11th to 20th	Day	16% 9% 3 5% 5% 4 3 2 4 5% 44%	2050
	21st to end	Day	19% 13% 5% 6% 4 3 3 3 4 5% 34%	3135
January	1st to 10th	Night	13% 10% 4 8% 4 4 4 3 4 4 42%	4108
	11th to 20th	Night	13% 7% 2 5% 3 3 2 2 4 5% 55%	4120
	21st to end	Night	23% 8% 3 4 3 2 2 2 3 5% 46%	4532
February	1st to 10th	Night	18% 9% 3 6% 4 3 3 3 5% 6% 41%	2470
	11th to 20th	Night	17% 7% 3 4 3 3 2 3 4 7% 45%	2383
	21st to end	Night	19% 7% 2 5% 3 3 3 4 4 5% 46%	1760
March	1st to 10th	Night	23% 8% 2 5% 4 3 3 2 4 5% 41%	3419
	11th to 20th	Night	17% 7% 2 5% 4 3 3 2 4 5% 47%	3480
	21st to end	Night	17% 6% 2 7% 4 4 4 3 5% 6% 42%	3817
April	1st to 10th	Night	16% 6% 2 5% 3 3 4 3 5% 6% 47%	1967
	11th to 20th	Night	17% 6% 2 5% 3 4 3 2 5% 6% 47%	1875
	21st to end	Night	20% 5% 2 5% 4 3 3 4 5% 6% 41%	1900
May	1st to 10th	Night	21% 7% 2 5% 3 3 3 3 4 6% 42%	2898
	11th to 20th	Night	15% 6% 2 6% 4 4 5% 4 6% 6% 42%	2823
	21st to end	Night	20% 7% 2 5% 4 4 3 3 6% 7% 39%	3090
June	1st to 10th	Night	7% 4 1 3 3 3 4 4 6% 9% 54%	1710
	11th to 20th	Night	6% 3 1 2 3 4 4 4 6% 11% 55%	1710
	21st to end	Night	6% 3 1 3 4 3 3 4 6% 9% 60%	1710
July	1st to 10th	Night	10% 4 2 5% 4 3 4 4 6% 8% 49%	2850
	11th to 20th	Night	4 3 1 4 3 3 2 4 5% 9% 62%	2850
	21st to end	Night	9% 6% 3 7% 5% 4 4 4 6% 9% 43%	3098
August	1st to 10th	Night	4 3 2 5% 4 4 5% 4 6% 10% 53%	1701
	11th to 20th	Night	7% 4 2 5% 4 4 5% 4 6% 10% 49%	1752
	21st to end	Night	5% 4 2 4 3 3 4 4 6% 9% 55%	2080
September	1st to 10th	Night	8% 4 1 4 3 3 3 4 5% 8% 56%	1800
	11th to 20th	Night	10% 5% 2 5% 4 3 5% 4 5% 6% 52%	1912
	21st to end	Night	9% 5% 2 4 3 3 4 4 5% 5% 58%	2004
October	1st to 10th	Night	8% 3 1 3 3 3 4 4 5% 8% 58%	2160
	11th to 20th	Night	15% 5% 2 4 3 2 3 3 4 5% 56%	2160
	21st to end	Night	20% 6% 1 4 2 2 3 3 3 5% 51%	2376
November	1st to 10th	Night	14% 5% 2 4 3 2 3 3 3 4 57%	2220
	11th to 20th	Night	14% 6% 2 4 3 2 3 3 4 6% 55%	2280
	21st to end	Night	20% 6% 2 4 3 3 2 2 4 5% 49%	2569
December	1st to 10th	Night	17% 7% 2 5% 3 4 3 3 4 6% 47%	2660
	11th to 20th	Night	17% 9% 2 6% 4 3 3 3 4 4 45%	3132
	21st to end	Night	21% 10% 5% 8% 4 3 4 2 3 4 36%	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	42% 4 6% 23% 22% 3	2848
	11th to 20th	Day	36% 4 12% 24% 20% 4	2850
	21st to end	Day	44% 4 6% 20% 19% 8%	3135
February	1st to 10th	Day	46% 4 10% 20% 17% 4	1710
	11th to 20th	Day	45% 3 8% 21% 19% 4	1692
	21st to end	Day	47% 4 8% 16% 17% 8%	1711
March	1st to 10th	Day	44% 6% 7% 17% 16% 11%	3436
	11th to 20th	Day	38% 5% 11% 22% 19% 4	3480
	21st to end	Day	47% 6% 10% 21% 15% 1	3814
April	1st to 10th	Day	42% 6% 9% 20% 20% 4	2211
	11th to 20th	Day	45% 6% 10% 19% 17% 4	2254
	21st to end	Day	49% 5% 8% 21% 15% 2	2280
May	1st to 10th	Day	51% 7% 8% 20% 13% 1	4038
	11th to 20th	Day	41% 10% 12% 25% 12% 1	4086
	21st to end	Day	48% 9% 13% 17% 13% 1	4489
June	1st to 10th	Day	38% 8% 14% 25% 13% 1	2470
	11th to 20th	Day	35% 9% 14% 25% 15% 2	2470
	21st to end	Day	27% 8% 15% 29% 17% 4	2470
July	1st to 10th	Day	35% 6% 20% 25% 12% 2	4056
	11th to 20th	Day	27% 5% 13% 37% 17% 1	4051
	21st to end	Day	41% 7% 19% 25% 8%	4325
August	1st to 10th	Day	33% 10% 19% 24% 13% 2	2444
	11th to 20th	Day	36% 8% 13% 25% 16% 1	2368
	21st to end	Day	32% 7% 16% 25% 15% 4	2485
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	43% 6% 7% 17% 24% 3	4108
	11th to 20th	Night	33% 3 12% 24% 24% 4	4120
	21st to end	Night	42% 4 9% 19% 20% 6%	4532
February	1st to 10th	Night	45% 4 9% 22% 16% 5%	2470
	11th to 20th	Night	40% 4 7% 24% 19% 5%	2384
	21st to end	Night	40% 4 8% 18% 20% 9%	1760
March	1st to 10th	Night	45% 5% 7% 18% 15% 10%	3419
	11th to 20th	Night	39% 5% 10% 24% 18% 4	3480
	21st to end	Night	41% 6% 12% 26% 14% 2	3817
April	1st to 10th	Night	38% 5% 9% 21% 20% 7%	1967
	11th to 20th	Night	38% 5% 8% 23% 19% 7%	1875
	21st to end	Night	42% 6% 10% 23% 17% 2	1900
May	1st to 10th	Night	42% 7% 12% 21% 15% 3	2926
	11th to 20th	Night	39% 8% 15% 24% 13% 1	2824
	21st to end	Night	41% 9% 14% 20% 13% 2	3099
June	1st to 10th	Night	25% 8% 16% 31% 18% 3	1710
	11th to 20th	Night	22% 7% 15% 33% 21% 2	1710
	21st to end	Night	21% 6% 16% 28% 22% 6%	1710
July	1st to 10th	Night	32% 6% 22% 22% 15% 3	2805
	11th to 20th	Night	20% 5% 12% 40% 22% 1	2796
	21st to end	Night	37% 4 18% 29% 11% 1	2999
August	1st to 10th	Night	24% 8% 19% 33% 16% 1	1691
	11th to 20th	Night	30% 7% 16% 25% 21% 2	1752
	21st to end	Night	24% 8% 16% 29% 20% 4	2080
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	24% 31% 28% 13% 4	297
February	1st to 10th	Day	32% 24% 32% 9% 3	270
	11th to 20th	Day	33% 29% 29% 7% 3	270
	21st to end	Day	41% 25% 28% 4 2	225
March	1st to 10th	Day	28% 26% 33% 11% 3	270
	11th to 20th	Day	32% 24% 34% 8% 2	270
	21st to end	Day	34% 31% 26% 8% 2	297
April	1st to 10th	Day	28% 26% 26% 13% 7% 1	391
	11th to 20th	Day	29% 21% 29% 15% 5%	452
	21st to end	Day	29% 20% 31% 15% 6%	460
May	1st to 10th	Day	23% 19% 35% 18% 5% 1	597
	11th to 20th	Day	19% 12% 30% 26% 10% 3	675
	21st to end	Day	15% 11% 33% 26% 12% 3	734
June	1st to 10th	Day	11% 7% 24% 35% 20% 4	680
	11th to 20th	Day	7% 5% 24% 39% 22% 3	680
	21st to end	Day	6% 4 30% 35% 20% 5%	680
July	1st to 10th	Day	10% 3 17% 35% 27% 8%	671
	11th to 20th	Day	6% 3 19% 33% 30% 9%	668
	21st to end	Day	8% 2 13% 36% 32% 9%	739
August	1st to 10th	Day	8% 4 16% 39% 28% 5%	676
	11th to 20th	Day	14% 2 14% 36% 27% 6%	602
	21st to end	Day	8% 2 11% 32% 34% 12%	532
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% 28% 4	1045
February	1st to 10th	Night	23% 21% 27% 25% 4	950
	11th to 20th	Night	23% 23% 31% 20% 3	909
	21st to end	Night	28% 20% 31% 19% 2	504
March	1st to 10th	Night	22% 16% 28% 29% 5%	570
	11th to 20th	Night	24% 15% 28% 29% 5%	570
	21st to end	Night	23% 18% 32% 21% 6%	627
April	1st to 10th	Night	21% 18% 30% 24% 6%	570
	11th to 20th	Night	18% 18% 29% 26% 8% 1	563
	21st to end	Night	21% 15% 32% 21% 10%	570
May	1st to 10th	Night	19% 9% 31% 30% 10%	570
	11th to 20th	Night	16% 10% 24% 31% 18% 1	561
	21st to end	Night	14% 5% 29% 29% 19% 4	617
June	1st to 10th	Night	8% 4 14% 40% 31% 3	570
	11th to 20th	Night	6% 2 20% 40% 28% 3	570
	21st to end	Night	6% 3 16% 37% 33% 4	570
July	1st to 10th	Night	7% 2 9% 32% 43% 6%	555
	11th to 20th	Night	4 3 10% 36% 39% 9%	552
	21st to end	Night	5% 2 8% 33% 45% 8%	624
August	1st to 10th	Night	4 2 11% 39% 38% 7%	567
	11th to 20th	Night	8% 1 12% 37% 37% 5%	564
	21st to end	Night	7% 1 10% 36% 41% 6%	624
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 2024-08-27 08:49:44. Version ac07

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