De Queen
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the De Queen clear sky chart from 2005-11-06 to 2026-04-17.

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% 2 5% 4 4 4 3 5% 7% 46%	131866
	Night	14% 5% 2 5% 3 3 3 3 4 6% 51%	130579
Transparency	Day	38% 2 10% 24% 19% 6%	135476
	Night	35% 2 9% 23% 23% 9%	135046
Seeing	Day	16% 8% 22% 27% 21% 6%	17140
	Night	17% 7% 23% 32% 19% 2	27079

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% 7% 2 5% 3 3 3 2 4 6% 48%	5289
	11th to 20th	Day	9% 6% 2 5% 3 3 3 3 4 5% 58%	5310
	21st to end	Day	23% 6% 2 5% 3 3 3 3 4 4 45%	5812
February	1st to 10th	Day	25% 7% 2 5% 3 4 3 2 3 5% 40%	1890
	11th to 20th	Day	22% 7% 3 5% 4 3 3 3 4 5% 41%	1935
	21st to end	Day	25% 6% 2 5% 4 2 3 2 3 4 43%	1903
March	1st to 10th	Day	25% 8% 2 5% 3 3 3 3 4 5% 41%	5046
	11th to 20th	Day	13% 6% 2 5% 3 4 3 3 5% 6% 49%	5090
	21st to end	Day	19% 8% 3 7% 4 3 4 2 5% 5% 41%	5583
April	1st to 10th	Day	19% 7% 2 6% 4 3 3 3 4 6% 42%	2394
	11th to 20th	Day	19% 7% 2 5% 4 3 3 3 5% 6% 42%	2446
	21st to end	Day	18% 8% 3 5% 4 4 4 2 4 6% 42%	2400
May	1st to 10th	Day	24% 7% 2 6% 4 3 3 3 5% 7% 37%	5695
	11th to 20th	Day	15% 7% 3 7% 5% 4 5% 4 6% 7% 38%	5862
	21st to end	Day	17% 7% 3 7% 5% 4 4 4 5% 7% 36%	6434
June	1st to 10th	Day	9% 5% 2 6% 4 5% 5% 5% 7% 10% 43%	2600
	11th to 20th	Day	9% 6% 2 6% 5% 5% 6% 5% 6% 8% 43%	2600
	21st to end	Day	5% 4 2 5% 4 5% 6% 5% 7% 10% 49%	2600
July	1st to 10th	Day	9% 5% 2 7% 6% 6% 6% 5% 7% 11% 36%	5900
	11th to 20th	Day	6% 3 1 3 3 3 4 3 5% 9% 59%	5900
	21st to end	Day	8% 6% 3 7% 5% 4 5% 4 6% 9% 44%	6422
August	1st to 10th	Day	4 2 1 4 4 4 5% 4 6% 8% 60%	4234
	11th to 20th	Day	7% 4 2 5% 3 4 5% 4 7% 9% 50%	4048
	21st to end	Day	6% 3 2 5% 4 4 6% 5% 7% 9% 49%	4312
September	1st to 10th	Day	10% 6% 2 6% 4 4 4 3 5% 7% 49%	2390
	11th to 20th	Day	11% 4 2 6% 4 4 5% 4 6% 8% 47%	2200
	21st to end	Day	11% 4 1 5% 4 3 4 3 5% 6% 54%	2188
October	1st to 10th	Day	8% 4 1 5% 4 4 3 3 4 5% 59%	2000
	11th to 20th	Day	14% 5% 2 4 2 2 2 2 3 4 59%	2000
	21st to end	Day	20% 6% 2 5% 3 2 3 3 3 4 50%	2200
November	1st to 10th	Day	17% 6% 2 4 3 2 3 2 4 6% 51%	2058
	11th to 20th	Day	15% 5% 2 3 2 3 3 2 5% 5% 54%	2100
	21st to end	Day	21% 6% 2 5% 3 2 3 2 3 4 49%	1927
December	1st to 10th	Day	21% 6% 2 5% 2 2 2 2 4 4 50%	3030
	11th to 20th	Day	26% 7% 2 5% 3 2 2 2 3 5% 43%	3481
	21st to end	Day	24% 9% 2 6% 3 3 3 2 3 4 40%	4587
January	1st to 10th	Night	15% 6% 2 5% 3 3 3 3 5% 6% 50%	7634
	11th to 20th	Night	10% 4 1 3 2 2 2 2 3 4 69%	7680
	21st to end	Night	26% 6% 2 5% 3 3 3 2 3 4 44%	8402
February	1st to 10th	Night	21% 6% 2 5% 3 3 3 2 4 5% 45%	2730
	11th to 20th	Night	21% 8% 2 5% 3 3 3 3 5% 4 44%	2586
	21st to end	Night	20% 6% 2 4 3 2 2 2 3 4 51%	1903
March	1st to 10th	Night	23% 6% 2 6% 4 3 3 3 4 5% 42%	5029
	11th to 20th	Night	13% 5% 2 4 3 3 4 3 4 6% 52%	5090
	21st to end	Night	17% 6% 3 6% 3 3 3 3 5% 6% 46%	5588
April	1st to 10th	Night	16% 5% 2 6% 4 3 3 3 4 4 49%	2226
	11th to 20th	Night	15% 5% 2 5% 3 3 3 4 4 6% 49%	2035
	21st to end	Night	16% 6% 2 5% 4 2 2 3 4 6% 50%	2000
May	1st to 10th	Night	23% 7% 2 6% 4 4 4 3 5% 6% 37%	4196
	11th to 20th	Night	17% 6% 2 6% 4 4 4 4 5% 7% 40%	4053
	21st to end	Night	16% 7% 2 6% 3 4 4 3 5% 8% 42%	4443
June	1st to 10th	Night	6% 5% 2 5% 4 4 4 4 5% 9% 54%	1800
	11th to 20th	Night	6% 5% 1 5% 4 3 4 3 6% 9% 55%	1800
	21st to end	Night	4 4 1 3 3 4 3 3 6% 8% 61%	1800
July	1st to 10th	Night	7% 4 2 6% 4 6% 5% 4 8% 11% 43%	4078
	11th to 20th	Night	5% 3 1 4 3 3 3 3 5% 10% 60%	4077
	21st to end	Night	6% 5% 2 6% 4 5% 4 4 6% 9% 50%	4449
August	1st to 10th	Night	3 2 1 3 2 2 3 3 5% 7% 69%	2926
	11th to 20th	Night	4 2 1 4 3 3 3 4 6% 12% 57%	3006
	21st to end	Night	3 4 1 5% 4 4 5% 4 7% 9% 55%	3586
September	1st to 10th	Night	7% 4 2 5% 2 3 4 3 5% 6% 59%	2005
	11th to 20th	Night	9% 5% 1 5% 4 4 6% 4 6% 7% 50%	2200
	21st to end	Night	9% 3 1 5% 4 3 3 4 4 5% 59%	2200
October	1st to 10th	Night	8% 3 1 3 2 3 3 3 4 6% 64%	2390
	11th to 20th	Night	12% 4 2 3 2 2 2 2 3 5% 61%	2400
	21st to end	Night	18% 5% 2 4 3 3 2 2 3 4 55%	2640
November	1st to 10th	Night	15% 5% 2 3 3 2 3 3 3 4 58%	2460
	11th to 20th	Night	12% 5% 2 4 3 2 3 3 3 5% 59%	2520
	21st to end	Night	19% 6% 2 4 3 3 3 2 3 5% 50%	2688
December	1st to 10th	Night	17% 7% 2 4 3 3 3 3 4 4 50%	4380
	11th to 20th	Night	22% 6% 3 6% 4 3 3 2 3 3 46%	4946
	21st to end	Night	21% 10% 2 5% 3 2 2 2 3 4 45%	6633

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% 1 9% 30% 18% 2	5290
	11th to 20th	Day	31% 2 7% 25% 32% 4	5310
	21st to end	Day	46% 1 4 17% 22% 10%	5812
February	1st to 10th	Day	50% 2 6% 19% 19% 5%	1890
	11th to 20th	Day	47% 1 6% 21% 19% 5%	1944
	21st to end	Day	47% 2 5% 14% 22% 9%	1903
March	1st to 10th	Day	47% 1 5% 15% 18% 13%	5046
	11th to 20th	Day	37% 1 6% 16% 21% 18%	5090
	21st to end	Day	48% 2 8% 24% 16% 2	5585
April	1st to 10th	Day	44% 1 8% 22% 18% 7%	2394
	11th to 20th	Day	43% 2 9% 21% 20% 6%	2446
	21st to end	Day	45% 2 9% 21% 20% 3	2400
May	1st to 10th	Day	49% 2 9% 26% 12% 1	5731
	11th to 20th	Day	46% 2 12% 21% 18% 2	5866
	21st to end	Day	48% 3 13% 20% 14% 3	6447
June	1st to 10th	Day	36% 4 14% 29% 16% 2	2600
	11th to 20th	Day	37% 4 12% 27% 18% 2	2600
	21st to end	Day	29% 5% 12% 32% 20% 2	2600
July	1st to 10th	Day	40% 6% 20% 26% 8%	5836
	11th to 20th	Day	22% 3 16% 39% 18% 1	5831
	21st to end	Day	37% 4 16% 33% 10% 1	6240
August	1st to 10th	Day	21% 3 14% 28% 29% 4	4220
	11th to 20th	Day	30% 4 20% 34% 11% 1	4087
	21st to end	Day	31% 5% 16% 33% 14% 2	4311
September	1st to 10th	Day	35% 4 11% 21% 20% 9%	2390
	11th to 20th	Day	36% 4 10% 25% 18% 6%	2200
	21st to end	Day	31% 3 9% 22% 25% 10%	2188
October	1st to 10th	Day	18% 1 6% 11% 34% 30%	3260
	11th to 20th	Day	21% 2 3 20% 34% 20%	3240
	21st to end	Day	32% 3 5% 27% 26% 7%	3538
November	1st to 10th	Day	36% 2 6% 22% 26% 7%	2058
	11th to 20th	Day	33% 2 6% 21% 28% 9%	2100
	21st to end	Day	42% 1 5% 19% 26% 6%	1927
December	1st to 10th	Day	40% 2 7% 30% 18% 3	3030
	11th to 20th	Day	47% 1 4 21% 21% 6%	3479
	21st to end	Day	50% 1 4 21% 20% 4	4587
January	1st to 10th	Night	37% 1 8% 28% 23% 3	7635
	11th to 20th	Night	23% 1 5% 21% 37% 12%	7680
	21st to end	Night	48% 1 5% 14% 21% 10%	8402
February	1st to 10th	Night	43% 1 6% 20% 21% 8%	2730
	11th to 20th	Night	44% 2 6% 19% 22% 7%	2587
	21st to end	Night	40% 1 6% 16% 24% 12%	1903
March	1st to 10th	Night	46% 2 5% 14% 20% 14%	5029
	11th to 20th	Night	35% 2 6% 20% 19% 20%	5090
	21st to end	Night	41% 1 8% 22% 23% 4	5588
April	1st to 10th	Night	39% 2 8% 21% 19% 11%	2226
	11th to 20th	Night	38% 2 8% 20% 22% 10%	2035
	21st to end	Night	38% 2 9% 24% 24% 4	2000
May	1st to 10th	Night	49% 2 11% 24% 10% 3	4225
	11th to 20th	Night	45% 2 12% 22% 17% 2	4054
	21st to end	Night	43% 3 14% 20% 13% 7%	4452
June	1st to 10th	Night	28% 4 13% 31% 21% 4	1800
	11th to 20th	Night	25% 4 12% 32% 24% 3	1800
	21st to end	Night	22% 4 11% 31% 28% 5%	1800
July	1st to 10th	Night	33% 6% 20% 29% 11% 1	4035
	11th to 20th	Night	21% 4 13% 39% 21% 2	4026
	21st to end	Night	31% 4 16% 30% 17% 2	4320
August	1st to 10th	Night	15% 3 13% 28% 34% 7%	2916
	11th to 20th	Night	21% 3 20% 35% 18% 3	3033
	21st to end	Night	26% 5% 14% 28% 24% 3	3586
September	1st to 10th	Night	28% 3 10% 23% 26% 10%	2005
	11th to 20th	Night	32% 4 10% 25% 20% 9%	2200
	21st to end	Night	27% 3 8% 23% 27% 13%	2200
October	1st to 10th	Night	15% 2 5% 15% 25% 38%	3910
	11th to 20th	Night	18% 2 3 16% 37% 24%	3899
	21st to end	Night	28% 2 4 24% 29% 13%	4252
November	1st to 10th	Night	32% 2 7% 20% 28% 11%	2460
	11th to 20th	Night	31% 1 7% 20% 28% 13%	2520
	21st to end	Night	39% 1 5% 19% 27% 8%	2688
December	1st to 10th	Night	39% 2 6% 27% 21% 5%	4380
	11th to 20th	Night	47% 1 4 18% 20% 10%	4947
	21st to end	Night	45% 1 6% 21% 22% 4	6633

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	28% 11% 31% 25% 5%	330
	11th to 20th	Day	21% 20% 37% 17% 5% 1	330
	21st to end	Day	22% 18% 37% 19% 4	363
February	1st to 10th	Day	30% 14% 35% 17% 4	330
	11th to 20th	Day	29% 22% 35% 12% 3	330
	21st to end	Day	33% 17% 36% 9% 5%	273
March	1st to 10th	Day	29% 17% 33% 16% 4	330
	11th to 20th	Day	29% 20% 33% 14% 3 1	330
	21st to end	Day	23% 18% 37% 20% 3	363
April	1st to 10th	Day	25% 17% 32% 19% 8%	414
	11th to 20th	Day	26% 16% 29% 21% 6% 2	516
	21st to end	Day	22% 16% 28% 26% 7% 2	500
May	1st to 10th	Day	18% 12% 31% 29% 9%	625
	11th to 20th	Day	17% 10% 26% 29% 17% 2	725
	21st to end	Day	14% 6% 27% 32% 16% 5%	789
June	1st to 10th	Day	11% 5% 15% 33% 29% 8%	730
	11th to 20th	Day	9% 3 17% 37% 26% 7%	730
	21st to end	Day	5% 3 15% 32% 35% 10%	730
July	1st to 10th	Day	7% 2 11% 30% 37% 12%	721
	11th to 20th	Day	6% 1 8% 31% 41% 14%	718
	21st to end	Day	6% 2 8% 31% 39% 15%	794
August	1st to 10th	Day	6% 1 8% 33% 42% 11%	726
	11th to 20th	Day	12% 1 9% 29% 38% 13%	644
	21st to end	Day	10% 7% 24% 40% 19%	583
September	1st to 10th	Day	9% 2 11% 25% 39% 14%	520
	11th to 20th	Day	7% 2 12% 32% 31% 16%	330
	21st to end	Day	13% 4 16% 30% 28% 9%	330
October	1st to 10th	Day	5% 1 24% 34% 30% 6%	330
	11th to 20th	Day	13% 9% 29% 31% 15% 2	330
	21st to end	Day	26% 12% 24% 25% 10% 3	363
November	1st to 10th	Day	23% 9% 28% 25% 12% 2	330
	11th to 20th	Day	18% 13% 32% 28% 9% 1	330
	21st to end	Day	23% 16% 28% 21% 10% 2	330
December	1st to 10th	Day	25% 13% 32% 20% 8% 2	330
	11th to 20th	Day	28% 13% 33% 20% 6%	330
	21st to end	Day	24% 16% 33% 21% 5% 1	363
January	1st to 10th	Night	23% 12% 28% 32% 5%	1050
	11th to 20th	Night	21% 11% 33% 28% 6% 1	1050
	21st to end	Night	22% 11% 32% 31% 4	1155
February	1st to 10th	Night	24% 12% 30% 28% 6%	1050
	11th to 20th	Night	26% 14% 31% 25% 4	952
	21st to end	Night	24% 13% 35% 24% 4	519
March	1st to 10th	Night	23% 12% 29% 31% 4	630
	11th to 20th	Night	21% 10% 33% 30% 5%	630
	21st to end	Night	20% 9% 34% 30% 6%	693
April	1st to 10th	Night	19% 11% 34% 28% 7%	630
	11th to 20th	Night	17% 12% 31% 27% 12%	611
	21st to end	Night	19% 7% 34% 30% 10% 1	600
May	1st to 10th	Night	15% 6% 29% 39% 11% 1	600
	11th to 20th	Night	17% 6% 26% 31% 19% 2	591
	21st to end	Night	12% 3 24% 36% 22% 3	650
June	1st to 10th	Night	7% 3 12% 38% 36% 4	600
	11th to 20th	Night	7% 2 11% 44% 34% 3	600
	21st to end	Night	4 1 10% 34% 45% 7%	600
July	1st to 10th	Night	5% 1 9% 32% 48% 5%	585
	11th to 20th	Night	5% 6% 28% 52% 8%	582
	21st to end	Night	6% 5% 31% 49% 9%	657
August	1st to 10th	Night	4 1 5% 35% 48% 8%	597
	11th to 20th	Night	8% 1 8% 33% 44% 7%	594
	21st to end	Night	6% 1 8% 32% 47% 6%	660
September	1st to 10th	Night	7% 2 11% 33% 43% 6%	600
	11th to 20th	Night	11% 2 10% 34% 40% 4	600
	21st to end	Night	9% 2 15% 36% 34% 4	600
October	1st to 10th	Night	9% 2 13% 43% 30% 3	790
	11th to 20th	Night	15% 5% 21% 40% 19% 1	800
	21st to end	Night	20% 8% 23% 30% 17% 2	880
November	1st to 10th	Night	16% 5% 24% 37% 16% 1	820
	11th to 20th	Night	15% 8% 27% 38% 11% 1	840
	21st to end	Night	23% 10% 26% 29% 12% 1	1008
December	1st to 10th	Night	22% 7% 28% 35% 7%	1050
	11th to 20th	Night	27% 8% 26% 33% 6%	1050
	21st to end	Night	24% 9% 30% 29% 8%	1155

Page generated at 2026-04-14 01:44:30. Version ac07

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