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 2025-02-06.

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% 45%	108474
	Night	14% 6% 2 5% 3 3 3 3 4 6% 49%	109974
Transparency	Day	38% 5% 11% 23% 18% 5%	112124
	Night	35% 5% 10% 24% 21% 6%	114464
Seeing	Day	18% 13% 26% 25% 15% 3	15708
	Night	17% 12% 24% 30% 16% 2	25672

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 3 4 48%	4077
	11th to 20th	Day	8% 5% 3 7% 3 4 4 3 4 5% 54%	4080
	21st to end	Day	22% 6% 2 4 3 3 3 2 3 4 48%	4488
February	1st to 10th	Day	20% 10% 3 5% 4 3 3 2 4 5% 43%	1755
	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	5% 3 1 4 3 5% 5% 4 6% 10% 55%	4104
	11th to 20th	Day	12% 5% 2 6% 4 4 4 4 6% 9% 45%	3926
	21st to end	Day	5% 3 1 5% 4 5% 4 4 6% 9% 54%	4180
September	1st to 10th	Day	12% 6% 2 5% 3 4 4 3 5% 7% 50%	2280
	11th to 20th	Day	12% 4 1 5% 4 4 5% 5% 6% 9% 45%	2157
	21st to end	Day	9% 4 2 5% 5% 4 5% 3 5% 6% 53%	2043
October	1st to 10th	Day	10% 5% 1 5% 4 3 4 2 4 5% 56%	1900
	11th to 20th	Day	14% 5% 2 4 3 2 2 2 4 4 57%	1900
	21st to end	Day	21% 6% 2 4 2 3 2 2 3 4 50%	2090
November	1st to 10th	Day	15% 6% 2 3 3 3 2 2 3 6% 55%	1958
	11th to 20th	Day	14% 7% 2 4 3 2 3 3 4 5% 55%	2000
	21st to end	Day	21% 7% 2 5% 2 3 3 2 4 6% 47%	1684
December	1st to 10th	Day	15% 10% 2 3 3 3 3 2 3 4 52%	2610
	11th to 20th	Day	18% 8% 3 5% 4 3 3 2 4 5% 46%	3210
	21st to end	Day	22% 13% 4 6% 3 3 3 3 4 5% 34%	4488
January	1st to 10th	Night	14% 8% 3 8% 4 4 3 3 3 5% 46%	5888
	11th to 20th	Night	10% 6% 2 5% 3 2 2 2 4 5% 58%	5900
	21st to end	Night	21% 8% 3 5% 3 2 2 2 3 5% 47%	6490
February	1st to 10th	Night	18% 9% 3 6% 4 3 4 3 5% 6% 41%	2536
	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	3 3 1 4 3 3 4 3 6% 9% 60%	2836
	11th to 20th	Night	6% 4 2 6% 4 4 5% 3 6% 8% 53%	2908
	21st to end	Night	4 3 1 3 3 3 3 3 6% 8% 62%	3476
September	1st to 10th	Night	8% 4 1 4 3 3 3 4 5% 8% 57%	1900
	11th to 20th	Night	10% 5% 2 5% 3 3 5% 4 5% 6% 52%	2019
	21st to end	Night	9% 5% 2 4 3 3 4 4 5% 6% 56%	2116
October	1st to 10th	Night	7% 3 1 3 3 3 4 4 5% 7% 60%	2280
	11th to 20th	Night	14% 4 1 4 3 2 3 2 4 5% 58%	2280
	21st to end	Night	19% 6% 1 4 2 2 3 2 3 5% 52%	2508
November	1st to 10th	Night	15% 5% 2 4 3 2 3 3 3 4 56%	2340
	11th to 20th	Night	13% 6% 2 4 2 2 2 3 4 6% 56%	2400
	21st to end	Night	19% 6% 2 4 3 3 2 2 4 6% 50%	2705
December	1st to 10th	Night	13% 9% 2 4 3 3 3 2 4 5% 53%	4580
	11th to 20th	Night	21% 7% 2 5% 3 3 3 2 3 4 48%	4982
	21st to end	Night	24% 10% 4 7% 4 3 3 2 3 3 37%	6490

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% 3 7% 24% 22% 2	4078
	11th to 20th	Day	33% 3 8% 25% 26% 6%	4080
	21st to end	Day	42% 3 5% 19% 22% 10%	4488
February	1st to 10th	Day	45% 4 10% 20% 17% 4	1755
	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	25% 6% 16% 27% 21% 5%	4090
	11th to 20th	Day	36% 5% 17% 28% 12% 1	3965
	21st to end	Day	28% 5% 16% 36% 13% 2	4179
September	1st to 10th	Day	33% 6% 11% 24% 16% 9%	2280
	11th to 20th	Day	34% 7% 12% 23% 21% 4	2157
	21st to end	Day	31% 6% 10% 21% 28% 5%	2043
October	1st to 10th	Day	18% 3 7% 13% 38% 22%	3160
	11th to 20th	Day	20% 2 3 20% 38% 17%	3140
	21st to end	Day	33% 3 8% 29% 23% 5%	3428
November	1st to 10th	Day	33% 4 8% 26% 20% 9%	1958
	11th to 20th	Day	33% 4 7% 24% 22% 10%	2000
	21st to end	Day	40% 4 7% 20% 24% 5%	1684
December	1st to 10th	Day	38% 2 6% 29% 22% 3	2610
	11th to 20th	Day	43% 2 6% 21% 25% 3	3208
	21st to end	Day	53% 4 7% 21% 13% 2	4488
January	1st to 10th	Night	41% 4 9% 23% 19% 4	5888
	11th to 20th	Night	30% 2 9% 21% 32% 7%	5900
	21st to end	Night	42% 3 7% 18% 25% 6%	6490
February	1st to 10th	Night	44% 4 8% 23% 16% 4	2536
	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	21% 5% 17% 33% 23% 1	2826
	11th to 20th	Night	29% 4 20% 29% 16% 2	2935
	21st to end	Night	21% 5% 14% 38% 21% 2	3476
September	1st to 10th	Night	26% 6% 11% 29% 19% 9%	1900
	11th to 20th	Night	31% 7% 11% 22% 23% 6%	2019
	21st to end	Night	28% 5% 8% 24% 28% 7%	2116
October	1st to 10th	Night	14% 4 8% 13% 34% 27%	3800
	11th to 20th	Night	19% 3 4 17% 38% 20%	3779
	21st to end	Night	30% 2 5% 29% 25% 9%	4120
November	1st to 10th	Night	33% 4 8% 22% 25% 9%	2340
	11th to 20th	Night	30% 4 7% 24% 26% 10%	2400
	21st to end	Night	38% 3 7% 22% 25% 6%	2705
December	1st to 10th	Night	36% 2 7% 30% 21% 3	4580
	11th to 20th	Night	43% 2 5% 20% 20% 10%	4983
	21st to end	Night	51% 5% 7% 21% 12% 4	6490

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	31% 23% 30% 12% 4	300
	11th to 20th	Day	28% 28% 31% 11% 2	300
	21st to end	Day	25% 29% 29% 13% 4	330
February	1st to 10th	Day	31% 23% 34% 9% 3 1	285
	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%	539
September	1st to 10th	Day	11% 3 14% 32% 33% 8%	490
	11th to 20th	Day	8% 4 22% 38% 23% 5%	367
	21st to end	Day	12% 10% 25% 33% 18% 2	300
October	1st to 10th	Day	9% 11% 30% 29% 19% 2	300
	11th to 20th	Day	16% 16% 38% 24% 5% 2	300
	21st to end	Day	27% 18% 34% 17% 4	330
November	1st to 10th	Day	21% 17% 32% 20% 9% 1	300
	11th to 20th	Day	22% 21% 35% 17% 6% 1	300
	21st to end	Day	30% 20% 25% 18% 5% 1	300
December	1st to 10th	Day	24% 25% 28% 16% 6% 1	300
	11th to 20th	Day	28% 24% 28% 15% 4	300
	21st to end	Day	28% 24% 33% 12% 2	330
January	1st to 10th	Night	21% 20% 28% 26% 4	1000
	11th to 20th	Night	22% 21% 28% 25% 4	1000
	21st to end	Night	20% 20% 29% 27% 4	1100
February	1st to 10th	Night	22% 21% 28% 25% 4	976
	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% 40% 6%	627
September	1st to 10th	Night	9% 3 13% 33% 39% 3	570
	11th to 20th	Night	13% 2 12% 39% 29% 4	570
	21st to end	Night	11% 6% 18% 34% 28% 4	596
October	1st to 10th	Night	9% 6% 22% 35% 24% 3	760
	11th to 20th	Night	16% 13% 28% 30% 13%	760
	21st to end	Night	22% 14% 24% 25% 13% 2	836
November	1st to 10th	Night	17% 13% 27% 30% 13% 1	780
	11th to 20th	Night	18% 14% 29% 30% 8%	800
	21st to end	Night	23% 16% 24% 26% 10%	994
December	1st to 10th	Night	21% 16% 29% 28% 6%	1000
	11th to 20th	Night	24% 16% 25% 30% 5%	1000
	21st to end	Night	25% 19% 24% 28% 4	1100

Page generated at 2025-02-03 02:05:53. Version ac07

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