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 2024-12-24.

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% 45%	101631
	Night	14% 6% 2 5% 3 3 3 3 4 6% 51%	98575
Transparency	Day	39% 2 10% 24% 20% 6%	105280
	Night	35% 2 9% 23% 23% 9%	103066
Seeing	Day	16% 8% 22% 27% 21% 6%	15433
	Night	17% 7% 23% 32% 19% 2	25302

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	20% 9% 2 4 3 3 3 2 4 4 45%	2847
	11th to 20th	Day	14% 9% 2 4 2 3 3 2 3 4 53%	2850
	21st to end	Day	24% 7% 2 4 3 3 2 3 4 3 45%	3135
February	1st to 10th	Day	25% 8% 3 5% 4 4 3 2 4 5% 38%	1710
	11th to 20th	Day	22% 7% 3 5% 4 3 3 3 4 5% 42%	1745
	21st to end	Day	28% 7% 2 5% 4 2 2 2 3 3 40%	1727
March	1st to 10th	Day	22% 9% 2 6% 4 3 3 3 4 4 41%	3436
	11th to 20th	Day	18% 8% 3 6% 4 4 4 4 5% 6% 38%	3480
	21st to end	Day	20% 8% 3 7% 3 3 3 2 5% 5% 39%	3814
April	1st to 10th	Day	18% 7% 2 6% 4 2 3 3 4 6% 43%	2166
	11th to 20th	Day	20% 6% 2 5% 4 3 3 3 5% 6% 42%	2254
	21st to end	Day	19% 7% 3 5% 4 4 4 2 4 6% 42%	2280
May	1st to 10th	Day	25% 7% 3 5% 4 3 3 3 5% 6% 35%	3971
	11th to 20th	Day	14% 6% 2 5% 4 4 5% 4 6% 7% 43%	4082
	21st to end	Day	20% 9% 3 8% 5% 4 4 3 5% 7% 33%	4477
June	1st to 10th	Day	9% 5% 2 5% 4 5% 5% 5% 7% 10% 43%	2470
	11th to 20th	Day	8% 6% 2 6% 5% 4 6% 5% 6% 8% 44%	2470
	21st to end	Day	5% 4 2 5% 4 4 6% 5% 7% 10% 48%	2470
July	1st to 10th	Day	9% 4 2 6% 5% 5% 5% 5% 7% 10% 42%	4120
	11th to 20th	Day	6% 3 1 3 4 3 4 4 6% 9% 57%	4120
	21st to end	Day	10% 7% 3 9% 6% 5% 5% 4 7% 9% 34%	4465
August	1st to 10th	Day	3 2 1 4 4 4 5% 4 6% 8% 60%	4104
	11th to 20th	Day	7% 4 2 5% 3 4 5% 4 7% 9% 50%	3922
	21st to end	Day	5% 3 2 5% 4 4 6% 5% 7% 10% 49%	4180
September	1st to 10th	Day	11% 6% 2 6% 4 4 4 3 5% 7% 48%	2271
	11th to 20th	Day	11% 4 2 6% 4 3 5% 4 6% 7% 47%	2090
	21st to end	Day	10% 4 1 5% 4 3 4 3 5% 6% 54%	2079
October	1st to 10th	Day	8% 4 1 5% 4 4 3 3 5% 5% 58%	1900
	11th to 20th	Day	14% 5% 2 4 2 2 2 2 3 4 58%	1900
	21st to end	Day	20% 5% 2 5% 3 2 3 3 3 4 50%	2090
November	1st to 10th	Day	17% 6% 2 4 4 2 3 2 4 6% 50%	1958
	11th to 20th	Day	15% 5% 2 3 2 3 3 2 5% 5% 55%	2000
	21st to end	Day	21% 6% 2 5% 3 2 3 2 3 4 50%	1835
December	1st to 10th	Day	20% 6% 2 5% 2 2 3 2 5% 5% 48%	1800
	11th to 20th	Day	20% 9% 2 6% 4 3 3 3 4 4 43%	2251
	21st to end	Day	21% 8% 2 7% 4 4 4 3 4 4 39%	3162
January	1st to 10th	Night	15% 8% 2 6% 3 3 3 3 4 5% 49%	4108
	11th to 20th	Night	17% 7% 1 3 2 2 2 2 3 4 57%	4120
	21st to end	Night	25% 6% 2 4 2 2 3 3 3 4 46%	4532
February	1st to 10th	Night	21% 6% 2 5% 3 3 3 3 4 5% 45%	2470
	11th to 20th	Night	20% 8% 2 5% 3 3 3 3 5% 4 44%	2334
	21st to end	Night	22% 6% 2 4 3 2 2 2 3 4 49%	1727
March	1st to 10th	Night	23% 8% 2 6% 4 4 3 3 4 5% 39%	3419
	11th to 20th	Night	18% 7% 3 5% 4 3 3 2 4 6% 46%	3480
	21st to end	Night	17% 6% 3 6% 4 4 3 3 5% 6% 43%	3817
April	1st to 10th	Night	15% 5% 2 6% 4 4 3 4 4 5% 49%	2014
	11th to 20th	Night	15% 6% 2 5% 3 3 4 4 4 6% 49%	1875
	21st to end	Night	16% 6% 2 5% 4 2 2 3 4 6% 50%	1900
May	1st to 10th	Night	23% 8% 2 6% 4 4 4 3 4 6% 37%	2927
	11th to 20th	Night	16% 6% 2 5% 4 4 4 3 5% 7% 45%	2823
	21st to end	Night	17% 7% 2 5% 3 3 4 3 6% 9% 40%	3090
June	1st to 10th	Night	6% 4 2 5% 4 4 4 3 5% 9% 54%	1710
	11th to 20th	Night	5% 5% 1 4 4 3 4 3 6% 9% 57%	1710
	21st to end	Night	4 4 1 3 3 4 3 3 5% 8% 61%	1710
July	1st to 10th	Night	8% 3 2 5% 4 4 5% 4 7% 9% 50%	2850
	11th to 20th	Night	4 3 1 3 2 2 4 3 6% 10% 61%	2850
	21st to end	Night	8% 6% 2 7% 5% 5% 5% 4 7% 9% 42%	3098
August	1st to 10th	Night	3 2 1 3 2 2 3 3 5% 7% 69%	2836
	11th to 20th	Night	4 2 1 4 3 3 3 4 6% 12% 57%	2912
	21st to end	Night	3 4 1 4 4 4 5% 4 7% 9% 56%	3476
September	1st to 10th	Night	6% 4 2 5% 2 2 4 3 5% 6% 59%	1905
	11th to 20th	Night	10% 5% 1 5% 4 4 6% 4 5% 7% 50%	2090
	21st to end	Night	9% 3 1 5% 3 3 3 4 4 5% 60%	2090
October	1st to 10th	Night	9% 3 1 3 2 3 3 3 4 6% 63%	2270
	11th to 20th	Night	13% 4 2 3 2 2 2 2 3 5% 61%	2280
	21st to end	Night	17% 5% 2 3 3 3 2 2 3 4 57%	2508
November	1st to 10th	Night	15% 5% 2 3 3 2 3 3 3 4 56%	2340
	11th to 20th	Night	12% 5% 2 4 3 2 3 3 3 5% 59%	2400
	21st to end	Night	19% 6% 2 4 3 3 3 2 3 5% 50%	2560
December	1st to 10th	Night	19% 6% 2 4 3 3 3 3 4 4 48%	2600
	11th to 20th	Night	19% 5% 2 6% 4 3 3 3 3 4 48%	3166
	21st to end	Night	20% 8% 2 5% 3 3 3 3 4 5% 46%	4578

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% 1 5% 24% 21% 4	2848
	11th to 20th	Day	37% 1 9% 29% 21% 3	2850
	21st to end	Day	47% 1 5% 18% 22% 8%	3135
February	1st to 10th	Day	51% 1 6% 18% 18% 5%	1710
	11th to 20th	Day	47% 1 5% 21% 20% 6%	1754
	21st to end	Day	50% 2 5% 14% 21% 8%	1727
March	1st to 10th	Day	48% 1 6% 15% 21% 9%	3436
	11th to 20th	Day	48% 1 9% 19% 18% 5%	3480
	21st to end	Day	49% 2 8% 22% 18% 2	3814
April	1st to 10th	Day	43% 1 8% 22% 18% 7%	2166
	11th to 20th	Day	43% 2 8% 22% 20% 6%	2254
	21st to end	Day	44% 2 9% 21% 20% 3	2280
May	1st to 10th	Day	51% 2 8% 25% 12% 2	4007
	11th to 20th	Day	41% 2 11% 26% 20% 1	4086
	21st to end	Day	52% 3 12% 19% 12% 3	4489
June	1st to 10th	Day	36% 4 14% 29% 15% 2	2470
	11th to 20th	Day	36% 4 12% 27% 18% 2	2470
	21st to end	Day	29% 5% 12% 32% 20% 2	2470
July	1st to 10th	Day	37% 5% 21% 27% 10% 1	4056
	11th to 20th	Day	24% 3 12% 37% 23% 1	4051
	21st to end	Day	45% 4 15% 27% 8% 1	4325
August	1st to 10th	Day	21% 3 15% 27% 29% 4	4090
	11th to 20th	Day	30% 4 20% 34% 11% 1	3961
	21st to end	Day	30% 5% 16% 33% 14% 2	4179
September	1st to 10th	Day	36% 3 11% 21% 20% 10%	2271
	11th to 20th	Day	36% 4 9% 24% 19% 7%	2090
	21st to end	Day	31% 3 9% 22% 25% 10%	2079
October	1st to 10th	Day	18% 1 6% 11% 33% 31%	3160
	11th to 20th	Day	21% 2 3 19% 34% 21%	3140
	21st to end	Day	31% 3 5% 27% 27% 7%	3428
November	1st to 10th	Day	37% 2 6% 22% 25% 8%	1958
	11th to 20th	Day	34% 2 6% 20% 29% 10%	2000
	21st to end	Day	42% 1 5% 19% 27% 6%	1835
December	1st to 10th	Day	40% 2 8% 24% 20% 6%	1800
	11th to 20th	Day	46% 2 4 21% 20% 7%	2249
	21st to end	Day	50% 1 4 18% 22% 5%	3162
January	1st to 10th	Night	40% 1 4 20% 30% 5%	4108
	11th to 20th	Night	35% 1 9% 23% 27% 6%	4120
	21st to end	Night	46% 1 7% 15% 23% 8%	4532
February	1st to 10th	Night	44% 1 7% 19% 21% 7%	2470
	11th to 20th	Night	43% 2 6% 19% 22% 7%	2335
	21st to end	Night	42% 1 6% 16% 24% 11%	1727
March	1st to 10th	Night	49% 1 6% 15% 17% 12%	3419
	11th to 20th	Night	42% 1 7% 23% 16% 10%	3480
	21st to end	Night	44% 1 7% 22% 23% 3	3817
April	1st to 10th	Night	38% 2 8% 20% 19% 12%	2014
	11th to 20th	Night	37% 3 8% 20% 23% 10%	1875
	21st to end	Night	38% 2 8% 24% 24% 4	1900
May	1st to 10th	Night	50% 2 8% 23% 12% 5%	2956
	11th to 20th	Night	41% 1 11% 26% 19% 2	2824
	21st to end	Night	43% 3 14% 23% 12% 5%	3099
June	1st to 10th	Night	28% 4 13% 32% 21% 4	1710
	11th to 20th	Night	24% 3 12% 32% 24% 4	1710
	21st to end	Night	22% 4 10% 31% 28% 5%	1710
July	1st to 10th	Night	30% 5% 20% 30% 14% 2	2805
	11th to 20th	Night	19% 4 11% 39% 24% 3	2796
	21st to end	Night	38% 4 16% 26% 16% 1	2999
August	1st to 10th	Night	15% 3 13% 27% 35% 7%	2826
	11th to 20th	Night	21% 3 20% 34% 18% 3	2939
	21st to end	Night	25% 4 14% 29% 25% 3	3476
September	1st to 10th	Night	28% 3 10% 23% 26% 10%	1905
	11th to 20th	Night	33% 4 10% 23% 21% 9%	2090
	21st to end	Night	27% 3 8% 22% 27% 14%	2090
October	1st to 10th	Night	15% 2 5% 14% 25% 38%	3790
	11th to 20th	Night	18% 2 3 16% 37% 24%	3779
	21st to end	Night	28% 2 4 24% 29% 13%	4120
November	1st to 10th	Night	33% 2 7% 20% 27% 11%	2340
	11th to 20th	Night	31% 2 6% 19% 29% 13%	2400
	21st to end	Night	39% 2 5% 19% 28% 9%	2560
December	1st to 10th	Night	40% 1 8% 21% 22% 8%	2600
	11th to 20th	Night	43% 1 5% 18% 23% 10%	3167
	21st to end	Night	42% 1 5% 23% 23% 5%	4578

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% 10% 31% 26% 5%	270
	11th to 20th	Day	24% 20% 34% 15% 6% 1	270
	21st to end	Day	22% 18% 36% 20% 5%	297
February	1st to 10th	Day	30% 15% 32% 17% 5%	270
	11th to 20th	Day	29% 21% 34% 13% 3	270
	21st to end	Day	38% 17% 35% 6% 4	225
March	1st to 10th	Day	26% 19% 32% 18% 4	270
	11th to 20th	Day	29% 20% 31% 16% 4 1	270
	21st to end	Day	27% 19% 34% 18% 2	297
April	1st to 10th	Day	24% 18% 33% 18% 6%	346
	11th to 20th	Day	26% 14% 29% 21% 7% 2	452
	21st to end	Day	21% 17% 27% 25% 7% 3	460
May	1st to 10th	Day	18% 11% 31% 30% 10%	579
	11th to 20th	Day	16% 8% 27% 30% 18% 2	675
	21st to end	Day	13% 6% 26% 32% 17% 6%	734
June	1st to 10th	Day	11% 4 13% 33% 30% 8%	680
	11th to 20th	Day	9% 3 16% 37% 28% 8%	680
	21st to end	Day	5% 4 16% 32% 33% 11%	680
July	1st to 10th	Day	7% 2 12% 30% 36% 13%	671
	11th to 20th	Day	6% 1 8% 31% 41% 14%	668
	21st to end	Day	6% 2 8% 31% 38% 15%	739
August	1st to 10th	Day	6% 1 8% 34% 41% 11%	676
	11th to 20th	Day	12% 1 9% 29% 37% 11%	598
	21st to end	Day	9% 6% 24% 40% 20%	539
September	1st to 10th	Day	9% 2 10% 23% 41% 14%	481
	11th to 20th	Day	7% 3 13% 32% 31% 14%	300
	21st to end	Day	13% 4 15% 31% 28% 9%	300
October	1st to 10th	Day	6% 1 25% 32% 30% 6%	300
	11th to 20th	Day	14% 10% 30% 31% 13% 2	300
	21st to end	Day	25% 13% 23% 26% 11% 3	330
November	1st to 10th	Day	23% 9% 29% 24% 13% 3	300
	11th to 20th	Day	18% 13% 30% 28% 9% 1	300
	21st to end	Day	22% 17% 27% 22% 10% 2	300
December	1st to 10th	Day	24% 14% 33% 20% 8% 2	300
	11th to 20th	Day	27% 14% 34% 20% 5%	300
	21st to end	Day	24% 14% 38% 18% 6% 1	306
January	1st to 10th	Night	23% 12% 27% 32% 6%	950
	11th to 20th	Night	23% 11% 32% 27% 6% 1	950
	21st to end	Night	21% 11% 32% 31% 4	1045
February	1st to 10th	Night	24% 13% 29% 28% 7%	950
	11th to 20th	Night	25% 13% 32% 27% 4	860
	21st to end	Night	26% 13% 34% 23% 4	471
March	1st to 10th	Night	22% 12% 29% 33% 5%	570
	11th to 20th	Night	22% 10% 33% 30% 5%	570
	21st to end	Night	21% 9% 35% 29% 6%	627
April	1st to 10th	Night	19% 11% 35% 28% 8%	570
	11th to 20th	Night	17% 11% 31% 28% 13% 1	563
	21st to end	Night	19% 7% 35% 29% 10% 1	570
May	1st to 10th	Night	15% 6% 29% 38% 11% 1	570
	11th to 20th	Night	17% 5% 25% 32% 19% 2	561
	21st to end	Night	12% 2 24% 35% 24% 3	617
June	1st to 10th	Night	7% 3 12% 37% 37% 4	570
	11th to 20th	Night	6% 1 11% 44% 35% 3	570
	21st to end	Night	5% 1 10% 34% 43% 7%	570
July	1st to 10th	Night	5% 1 9% 32% 48% 5%	555
	11th to 20th	Night	5% 6% 29% 51% 9%	552
	21st to end	Night	6% 5% 31% 49% 8%	624
August	1st to 10th	Night	4 1 5% 34% 48% 8%	567
	11th to 20th	Night	8% 1 8% 34% 43% 6%	564
	21st to end	Night	6% 7% 32% 48% 6%	627
September	1st to 10th	Night	7% 2 11% 31% 44% 6%	570
	11th to 20th	Night	12% 2 10% 34% 39% 3	570
	21st to end	Night	9% 2 16% 35% 34% 4	570
October	1st to 10th	Night	10% 2 13% 42% 30% 3	750
	11th to 20th	Night	15% 5% 21% 40% 19% 1	760
	21st to end	Night	19% 8% 24% 30% 17% 2	836
November	1st to 10th	Night	17% 5% 24% 37% 16% 1	780
	11th to 20th	Night	15% 9% 27% 38% 12% 1	800
	21st to end	Night	23% 10% 25% 29% 12% 1	960
December	1st to 10th	Night	23% 7% 27% 35% 8%	1000
	11th to 20th	Night	27% 8% 26% 33% 6%	1000
	21st to end	Night	23% 9% 31% 29% 8%	1063

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