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 2024-07-31.

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	16% 6% 2 5% 4 4 4 3 5% 6% 44%	90134
	Night	15% 6% 2 5% 3 3 3 3 4 6% 50%	89730
Transparency	Day	41% 2 9% 23% 19% 5%	89906
	Night	37% 2 8% 23% 23% 7%	89563
Seeing	Day	16% 8% 22% 26% 22% 7%	14939
	Night	17% 7% 23% 32% 19% 2	24749

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% 5% 2 7% 6% 6% 6% 6% 9% 10% 34%	2470
	11th to 20th	Day	6% 4 1 4 5% 4 5% 5% 7% 10% 50%	2470
	21st to end	Day	7% 5% 2 6% 6% 5% 5% 4 8% 10% 42%	2678
August	1st to 10th	Day	5% 3 1 5% 5% 5% 6% 6% 8% 10% 46%	2328
	11th to 20th	Day	10% 4 1 6% 4 5% 5% 4 7% 8% 45%	2238
	21st to end	Day	7% 4 2 6% 6% 5% 6% 5% 7% 9% 44%	2376
September	1st to 10th	Day	11% 5% 2 6% 4 4 4 3 5% 7% 49%	2152
	11th to 20th	Day	11% 4 2 6% 4 4 5% 4 6% 7% 47%	1980
	21st to end	Day	11% 4 1 5% 3 3 4 3 5% 6% 54%	1970
October	1st to 10th	Day	9% 4 1 5% 4 4 4 3 5% 5% 56%	1800
	11th to 20th	Day	15% 6% 2 5% 2 2 3 2 3 4 57%	1800
	21st to end	Day	21% 5% 2 5% 3 2 3 3 3 4 49%	1980
November	1st to 10th	Day	16% 6% 2 4 4 2 3 2 4 6% 51%	1858
	11th to 20th	Day	15% 5% 2 4 2 3 3 3 5% 5% 54%	1900
	21st to end	Day	22% 6% 2 5% 3 2 3 2 2 4 49%	1744
December	1st to 10th	Day	20% 6% 2 5% 2 2 3 2 5% 5% 48%	1710
	11th to 20th	Day	19% 9% 2 6% 4 3 3 3 4 4 43%	2161
	21st to end	Day	21% 8% 2 7% 4 4 4 3 4 4 39%	3135
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	5% 4 2 5% 5% 5% 5% 4 8% 11% 47%	1710
	11th to 20th	Night	3 2 1 3 3 3 4 3 6% 11% 62%	1710
	21st to end	Night	4 4 1 4 5% 4 4 4 7% 10% 51%	1871
August	1st to 10th	Night	3 3 1 3 3 3 5% 5% 7% 11% 57%	1611
	11th to 20th	Night	7% 3 1 5% 3 3 4 4 7% 11% 52%	1662
	21st to end	Night	4 5% 1 5% 4 4 5% 4 7% 10% 50%	1980
September	1st to 10th	Night	6% 4 2 5% 2 2 4 3 5% 6% 59%	1804
	11th to 20th	Night	10% 5% 1 5% 4 3 6% 4 5% 7% 50%	1980
	21st to end	Night	9% 3 1 4 3 3 3 3 4 5% 61%	1980
October	1st to 10th	Night	9% 3 1 4 2 3 3 3 4 7% 61%	2150
	11th to 20th	Night	14% 4 2 3 2 3 2 2 3 6% 59%	2160
	21st to end	Night	18% 5% 2 3 3 3 2 2 3 4 56%	2376
November	1st to 10th	Night	13% 5% 2 3 3 3 3 3 3 4 58%	2220
	11th to 20th	Night	12% 5% 2 4 3 2 3 3 3 5% 58%	2280
	21st to end	Night	20% 6% 2 4 3 3 3 3 4 5% 49%	2432
December	1st to 10th	Night	19% 6% 2 4 3 3 3 3 4 4 48%	2470
	11th to 20th	Night	19% 5% 2 6% 4 3 3 3 3 4 48%	3036
	21st to end	Night	20% 8% 2 5% 3 3 3 3 4 5% 46%	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	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	41% 6% 17% 24% 11% 1	2406
	11th to 20th	Day	28% 4 15% 30% 21% 2	2401
	21st to end	Day	34% 4 19% 32% 10% 1	2537
August	1st to 10th	Day	31% 4 16% 31% 17% 1	2314
	11th to 20th	Day	35% 4 13% 28% 18% 2	2238
	21st to end	Day	35% 5% 15% 28% 13% 3	2376
September	1st to 10th	Day	35% 3 11% 21% 20% 8%	2152
	11th to 20th	Day	36% 4 10% 23% 19% 7%	1980
	21st to end	Day	32% 3 9% 22% 25% 11%	1970
October	1st to 10th	Day	31% 2 10% 19% 26% 11%	1800
	11th to 20th	Day	35% 1 5% 17% 28% 15%	1800
	21st to end	Day	40% 2 6% 18% 25% 10%	1980
November	1st to 10th	Day	36% 2 6% 22% 26% 8%	1858
	11th to 20th	Day	34% 2 6% 20% 30% 8%	1900
	21st to end	Day	43% 1 4 19% 26% 7%	1744
December	1st to 10th	Day	39% 2 8% 24% 20% 6%	1710
	11th to 20th	Day	46% 2 4 21% 20% 7%	2159
	21st to end	Day	50% 1 4 18% 21% 5%	3135
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% 6% 18% 28% 16% 2	1665
	11th to 20th	Night	17% 4 16% 34% 26% 3	1656
	21st to end	Night	27% 4 15% 33% 19% 1	1772
August	1st to 10th	Night	20% 4 18% 33% 23% 2	1601
	11th to 20th	Night	27% 3 14% 32% 20% 4	1662
	21st to end	Night	30% 4 13% 31% 19% 4	1980
September	1st to 10th	Night	27% 3 10% 24% 27% 9%	1804
	11th to 20th	Night	33% 4 10% 23% 21% 9%	1980
	21st to end	Night	26% 3 8% 22% 28% 14%	1980
October	1st to 10th	Night	25% 2 9% 25% 24% 15%	2150
	11th to 20th	Night	29% 2 6% 17% 28% 19%	2160
	21st to end	Night	35% 1 4 20% 26% 12%	2376
November	1st to 10th	Night	31% 2 7% 21% 28% 11%	2220
	11th to 20th	Night	32% 2 7% 20% 29% 12%	2280
	21st to end	Night	40% 2 5% 18% 27% 8%	2432
December	1st to 10th	Night	40% 1 8% 20% 22% 8%	2470
	11th to 20th	Night	42% 1 5% 18% 23% 10%	3037
	21st to end	Night	42% 1 5% 23% 23% 5%	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	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% 1 8% 31% 38% 15%	736
August	1st to 10th	Day	6% 1 8% 33% 40% 11%	626
	11th to 20th	Day	13% 1 9% 29% 37% 11%	552
	21st to end	Day	9% 7% 23% 41% 20%	495
September	1st to 10th	Day	9% 2 9% 21% 44% 16%	442
	11th to 20th	Day	6% 3 11% 32% 32% 16%	270
	21st to end	Day	13% 4 13% 31% 29% 9%	270
October	1st to 10th	Day	6% 1 27% 30% 29% 6%	270
	11th to 20th	Day	16% 10% 30% 29% 13% 3	270
	21st to end	Day	28% 13% 23% 22% 11% 3	297
November	1st to 10th	Day	21% 8% 30% 24% 14% 3	270
	11th to 20th	Day	18% 14% 31% 27% 9% 1	270
	21st to end	Day	25% 16% 25% 22% 10% 2	270
December	1st to 10th	Day	23% 14% 32% 20% 9% 2	270
	11th to 20th	Day	25% 13% 34% 22% 6%	270
	21st to end	Day	23% 15% 38% 18% 6% 1	297
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%	537
	11th to 20th	Night	9% 1 8% 34% 43% 6%	534
	21st to end	Night	6% 1 7% 31% 49% 7%	594
September	1st to 10th	Night	6% 2 11% 30% 45% 6%	540
	11th to 20th	Night	11% 1 9% 34% 40% 4	540
	21st to end	Night	9% 2 15% 35% 35% 4	540
October	1st to 10th	Night	10% 2 14% 41% 30% 3	710
	11th to 20th	Night	16% 5% 21% 38% 19% 1	720
	21st to end	Night	20% 8% 24% 28% 18% 2	792
November	1st to 10th	Night	15% 5% 24% 38% 16% 1	740
	11th to 20th	Night	15% 8% 27% 38% 12% 1	760
	21st to end	Night	24% 10% 25% 29% 13% 1	912
December	1st to 10th	Night	23% 8% 27% 34% 8%	950
	11th to 20th	Night	27% 8% 26% 34% 6%	950
	21st to end	Night	23% 9% 31% 29% 8%	1045

Page generated at 2024-07-28 08:52:12. Version ac07

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