Little Rock
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Little Rock clear sky chart from 2005-11-06 to 2026-06-16.

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	13% 6% 2 6% 4 4 4 4 5% 7% 45%	136541
	Night	13% 6% 2 5% 4 3 3 3 5% 6% 49%	135715
Transparency	Day	37% 5% 10% 24% 19% 5%	140147
	Night	35% 4 9% 23% 21% 7%	140190
Seeing	Day	15% 9% 23% 26% 20% 7%	17482
	Night	15% 7% 25% 33% 18% 2	27300

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% 8% 2 7% 4 3 3 3 4 5% 45%	5289
	11th to 20th	Day	10% 8% 2 5% 4 3 3 3 3 4 55%	5310
	21st to end	Day	22% 7% 2 5% 3 2 2 2 3 4 48%	5812
February	1st to 10th	Day	21% 8% 3 5% 3 3 3 4 3 5% 41%	1890
	11th to 20th	Day	18% 9% 3 6% 4 3 3 3 4 5% 42%	1999
	21st to end	Day	21% 7% 2 6% 4 4 4 3 4 5% 40%	1770
March	1st to 10th	Day	21% 9% 3 7% 4 4 4 3 4 5% 38%	5046
	11th to 20th	Day	10% 5% 2 5% 4 3 4 3 4 6% 53%	5090
	21st to end	Day	14% 7% 3 7% 4 4 3 3 5% 6% 44%	5615
April	1st to 10th	Day	14% 6% 2 6% 3 4 4 3 5% 7% 45%	2520
	11th to 20th	Day	15% 7% 2 6% 4 4 4 2 4 7% 45%	2494
	21st to end	Day	14% 8% 2 7% 5% 4 4 4 6% 7% 39%	2520
May	1st to 10th	Day	17% 8% 3 7% 4 4 4 3 5% 7% 38%	7021
	11th to 20th	Day	12% 6% 2 7% 5% 5% 5% 4 7% 7% 38%	7467
	21st to end	Day	17% 8% 3 9% 6% 6% 6% 5% 7% 8% 27%	8392
June	1st to 10th	Day	8% 5% 2 6% 5% 5% 5% 5% 8% 8% 42%	2914
	11th to 20th	Day	5% 4 2 5% 5% 5% 5% 5% 7% 10% 46%	2871
	21st to end	Day	4 4 1 5% 4 5% 6% 5% 8% 11% 49%	2647
July	1st to 10th	Day	6% 5% 2 7% 5% 6% 6% 6% 8% 12% 37%	5900
	11th to 20th	Day	4 3 2 5% 3 4 4 5% 7% 10% 53%	5900
	21st to end	Day	8% 6% 2 6% 5% 5% 5% 5% 7% 9% 40%	6422
August	1st to 10th	Day	3 3 1 4 3 3 4 4 6% 8% 61%	4220
	11th to 20th	Day	8% 5% 2 7% 4 5% 6% 4 7% 9% 42%	3849
	21st to end	Day	6% 3 2 6% 4 5% 5% 4 7% 8% 50%	4312
September	1st to 10th	Day	11% 5% 2 5% 4 4 5% 5% 6% 8% 45%	2400
	11th to 20th	Day	14% 5% 2 5% 3 4 5% 4 6% 7% 46%	2400
	21st to end	Day	10% 5% 2 5% 4 4 4 3 5% 6% 53%	2098
October	1st to 10th	Day	8% 4 1 4 3 3 3 3 5% 6% 60%	2000
	11th to 20th	Day	15% 4 1 3 2 3 2 2 3 6% 59%	2000
	21st to end	Day	18% 5% 2 4 3 3 3 2 3 5% 52%	2200
November	1st to 10th	Day	13% 6% 2 4 3 3 3 2 4 5% 56%	2058
	11th to 20th	Day	11% 6% 1 4 3 3 3 3 6% 7% 55%	2012
	21st to end	Day	18% 7% 2 6% 3 3 4 3 4 6% 45%	1865
December	1st to 10th	Day	18% 8% 2 5% 4 4 3 2 4 4 46%	2690
	11th to 20th	Day	18% 9% 3 6% 4 3 3 3 4 4 44%	3088
	21st to end	Day	19% 7% 3 7% 4 4 4 3 5% 5% 41%	4460
January	1st to 10th	Night	17% 7% 2 5% 3 2 3 2 5% 5% 47%	7634
	11th to 20th	Night	11% 4 1 4 3 3 2 2 3 4 64%	7680
	21st to end	Night	23% 7% 3 5% 3 3 3 2 3 4 45%	8402
February	1st to 10th	Night	21% 8% 3 5% 3 3 3 3 3 6% 43%	2730
	11th to 20th	Night	19% 8% 2 6% 4 3 3 3 3 4 45%	2505
	21st to end	Night	19% 6% 2 4 3 3 3 2 4 5% 47%	2053
March	1st to 10th	Night	18% 7% 2 5% 4 3 3 3 4 5% 44%	5029
	11th to 20th	Night	11% 6% 2 5% 4 4 4 3 5% 6% 51%	5090
	21st to end	Night	13% 6% 3 7% 4 3 4 3 5% 7% 45%	5554
April	1st to 10th	Night	13% 5% 2 4 4 3 3 3 6% 7% 49%	2100
	11th to 20th	Night	12% 5% 2 4 4 3 3 4 5% 7% 51%	2075
	21st to end	Night	14% 6% 2 5% 4 3 3 3 5% 8% 46%	2100
May	1st to 10th	Night	18% 9% 2 6% 4 4 4 4 6% 7% 36%	5832
	11th to 20th	Night	15% 7% 3 7% 4 4 5% 3 5% 7% 38%	5400
	21st to end	Night	21% 8% 3 7% 4 4 5% 3 5% 6% 33%	5793
June	1st to 10th	Night	5% 4 2 5% 3 3 4 5% 6% 10% 52%	1696
	11th to 20th	Night	4 4 2 5% 3 4 4 4 5% 8% 57%	1640
	21st to end	Night	3 3 1 4 4 4 4 4 6% 8% 60%	1742
July	1st to 10th	Night	6% 5% 2 7% 6% 6% 5% 5% 7% 10% 42%	4078
	11th to 20th	Night	4 3 1 4 3 4 4 4 8% 13% 53%	4077
	21st to end	Night	6% 6% 2 5% 4 4 4 4 6% 10% 48%	4449
August	1st to 10th	Night	2 2 1 2 3 3 2 3 5% 8% 69%	2926
	11th to 20th	Night	4 3 2 5% 4 4 4 4 7% 10% 55%	3200
	21st to end	Night	3 3 1 5% 4 4 5% 4 6% 9% 56%	3586
September	1st to 10th	Night	6% 5% 2 5% 3 3 5% 4 5% 7% 55%	2000
	11th to 20th	Night	10% 5% 2 5% 3 3 4 3 5% 8% 52%	2000
	21st to end	Night	8% 4 1 5% 3 3 3 3 5% 6% 58%	2278
October	1st to 10th	Night	8% 4 2 5% 3 4 2 3 4 6% 62%	2400
	11th to 20th	Night	9% 4 2 5% 2 3 3 2 4 5% 62%	2400
	21st to end	Night	16% 5% 2 5% 3 3 3 3 3 3 54%	2640
November	1st to 10th	Night	12% 5% 2 5% 4 2 3 2 4 5% 56%	2460
	11th to 20th	Night	11% 4 1 4 3 3 3 3 4 6% 57%	2604
	21st to end	Night	14% 6% 2 5% 4 4 3 3 4 5% 51%	2751
December	1st to 10th	Night	16% 6% 2 5% 4 3 3 3 4 5% 51%	4720
	11th to 20th	Night	17% 9% 3 6% 4 3 3 2 3 4 45%	5339
	21st to end	Night	19% 7% 2 6% 4 3 4 3 4 5% 43%	6752

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 9% 28% 16% 2	5290
	11th to 20th	Day	34% 2 7% 21% 30% 5%	5310
	21st to end	Day	42% 3 4 17% 26% 8%	5812
February	1st to 10th	Day	46% 5% 9% 22% 15% 3	1890
	11th to 20th	Day	46% 3 8% 20% 18% 5%	2009
	21st to end	Day	47% 4 6% 15% 19% 8%	1770
March	1st to 10th	Day	49% 4 6% 15% 15% 11%	5046
	11th to 20th	Day	32% 4 7% 20% 25% 12%	5090
	21st to end	Day	42% 4 8% 24% 20% 2	5617
April	1st to 10th	Day	37% 6% 9% 24% 19% 5%	2520
	11th to 20th	Day	40% 4 10% 21% 17% 7%	2494
	21st to end	Day	43% 6% 10% 20% 18% 2	2520
May	1st to 10th	Day	46% 5% 8% 23% 16% 2	7056
	11th to 20th	Day	42% 7% 12% 22% 16% 2	7471
	21st to end	Day	52% 8% 12% 15% 11% 2	8405
June	1st to 10th	Day	34% 8% 13% 25% 17% 2	2914
	11th to 20th	Day	31% 7% 14% 28% 18% 2	2871
	21st to end	Day	26% 8% 14% 29% 20% 4	2647
July	1st to 10th	Day	35% 9% 15% 29% 11% 1	5836
	11th to 20th	Day	24% 6% 15% 36% 16% 2	5831
	21st to end	Day	37% 7% 15% 28% 12%	6240
August	1st to 10th	Day	20% 5% 16% 30% 24% 5%	4206
	11th to 20th	Day	37% 6% 14% 32% 10% 1	3885
	21st to end	Day	30% 7% 12% 29% 20% 3	4311
September	1st to 10th	Day	34% 7% 11% 22% 18% 7%	2400
	11th to 20th	Day	36% 7% 11% 19% 23% 6%	2400
	21st to end	Day	32% 5% 7% 22% 26% 8%	2098
October	1st to 10th	Day	15% 3 6% 13% 34% 29%	3260
	11th to 20th	Day	18% 2 4 20% 38% 18%	3240
	21st to end	Day	31% 3 4 27% 28% 7%	3538
November	1st to 10th	Day	31% 4 8% 26% 24% 7%	2058
	11th to 20th	Day	29% 4 8% 22% 26% 10%	2012
	21st to end	Day	43% 3 7% 18% 24% 5%	1865
December	1st to 10th	Day	44% 3 6% 26% 19% 3	2690
	11th to 20th	Day	45% 3 5% 22% 20% 5%	3085
	21st to end	Day	45% 4 8% 25% 14% 4	4460
January	1st to 10th	Night	40% 2 7% 29% 20% 2	7635
	11th to 20th	Night	27% 2 5% 19% 36% 11%	7680
	21st to end	Night	45% 3 6% 17% 21% 7%	8402
February	1st to 10th	Night	44% 3 7% 22% 18% 5%	2730
	11th to 20th	Night	44% 3 6% 21% 20% 6%	2506
	21st to end	Night	40% 3 8% 17% 23% 10%	2053
March	1st to 10th	Night	41% 5% 7% 14% 20% 13%	5029
	11th to 20th	Night	34% 4 6% 23% 18% 14%	5090
	21st to end	Night	39% 4 7% 26% 21% 3	5554
April	1st to 10th	Night	34% 5% 10% 23% 20% 8%	2100
	11th to 20th	Night	32% 5% 9% 23% 21% 10%	2075
	21st to end	Night	36% 4 10% 24% 22% 3	2100
May	1st to 10th	Night	47% 5% 12% 20% 13% 3	5862
	11th to 20th	Night	45% 6% 11% 21% 13% 5%	5401
	21st to end	Night	51% 7% 13% 16% 10% 3	5805
June	1st to 10th	Night	25% 8% 15% 29% 22% 2	1696
	11th to 20th	Night	24% 6% 13% 27% 24% 4	1640
	21st to end	Night	21% 5% 13% 31% 24% 6%	1742
July	1st to 10th	Night	34% 8% 15% 27% 15% 1	4035
	11th to 20th	Night	20% 7% 17% 36% 17% 3	4026
	21st to end	Night	31% 7% 14% 30% 18%	4320
August	1st to 10th	Night	13% 5% 16% 34% 26% 6%	2916
	11th to 20th	Night	22% 6% 19% 36% 15% 2	3230
	21st to end	Night	24% 6% 12% 28% 27% 3	3586
September	1st to 10th	Night	27% 7% 11% 26% 21% 9%	2000
	11th to 20th	Night	30% 6% 10% 22% 25% 7%	2000
	21st to end	Night	25% 5% 10% 22% 28% 10%	2278
October	1st to 10th	Night	16% 3 6% 15% 28% 31%	3920
	11th to 20th	Night	16% 2 4 16% 38% 24%	3899
	21st to end	Night	29% 3 4 21% 30% 13%	4252
November	1st to 10th	Night	31% 3 7% 22% 26% 11%	2460
	11th to 20th	Night	29% 3 6% 25% 26% 11%	2604
	21st to end	Night	36% 3 6% 20% 28% 6%	2751
December	1st to 10th	Night	38% 3 6% 32% 18% 4	4720
	11th to 20th	Night	45% 2 5% 20% 21% 7%	5341
	21st to end	Night	43% 4 8% 24% 17% 3	6752

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	25% 15% 37% 16% 6% 1	330
	11th to 20th	Day	24% 17% 36% 20% 2	330
	21st to end	Day	20% 20% 41% 15% 5%	363
February	1st to 10th	Day	24% 16% 34% 18% 7% 1	330
	11th to 20th	Day	28% 23% 34% 12% 3 1	330
	21st to end	Day	30% 18% 32% 15% 4 1	273
March	1st to 10th	Day	28% 17% 35% 14% 6%	330
	11th to 20th	Day	24% 22% 38% 15% 1	330
	21st to end	Day	22% 21% 38% 16% 4	370
April	1st to 10th	Day	21% 16% 33% 22% 7% 1	540
	11th to 20th	Day	21% 14% 34% 22% 8% 1	532
	21st to end	Day	21% 13% 31% 22% 11% 2	540
May	1st to 10th	Day	18% 12% 32% 27% 9% 1	543
	11th to 20th	Day	14% 7% 28% 31% 17% 3	717
	21st to end	Day	11% 6% 23% 34% 19% 6%	844
June	1st to 10th	Day	10% 3 18% 34% 26% 8%	780
	11th to 20th	Day	6% 4 17% 35% 29% 8%	756
	21st to end	Day	5% 3 16% 36% 30% 11%	730
July	1st to 10th	Day	5% 3 12% 30% 35% 14%	721
	11th to 20th	Day	5% 3 10% 31% 35% 17%	718
	21st to end	Day	8% 1 7% 31% 35% 17%	794
August	1st to 10th	Day	6% 2 10% 35% 37% 10%	725
	11th to 20th	Day	13% 1 8% 29% 34% 15%	519
	21st to end	Day	11% 1 5% 24% 42% 17%	583
September	1st to 10th	Day	10% 2 9% 29% 38% 12%	530
	11th to 20th	Day	12% 3 11% 24% 36% 15%	530
	21st to end	Day	10% 4 19% 33% 26% 8%	358
October	1st to 10th	Day	8% 4 24% 35% 23% 5%	330
	11th to 20th	Day	12% 11% 31% 27% 17% 3	330
	21st to end	Day	26% 11% 32% 19% 10% 2	363
November	1st to 10th	Day	18% 11% 29% 26% 13% 2	330
	11th to 20th	Day	13% 12% 38% 29% 6% 2	330
	21st to end	Day	25% 13% 31% 23% 8% 1	330
December	1st to 10th	Day	23% 18% 34% 17% 7% 1	330
	11th to 20th	Day	25% 15% 32% 20% 9%	330
	21st to end	Day	23% 19% 36% 17% 4 1	363
January	1st to 10th	Night	22% 8% 34% 29% 6%	1050
	11th to 20th	Night	20% 11% 37% 27% 4	1050
	21st to end	Night	21% 10% 37% 28% 3	1155
February	1st to 10th	Night	24% 11% 32% 28% 5%	1050
	11th to 20th	Night	25% 11% 39% 22% 2	870
	21st to end	Night	23% 14% 35% 25% 3	669
March	1st to 10th	Night	19% 9% 34% 33% 5%	630
	11th to 20th	Night	19% 13% 36% 27% 5%	630
	21st to end	Night	17% 12% 35% 29% 8%	693
April	1st to 10th	Night	17% 11% 36% 28% 7%	630
	11th to 20th	Night	14% 10% 38% 26% 12%	623
	21st to end	Night	16% 8% 35% 30% 10% 1	630
May	1st to 10th	Night	14% 6% 26% 44% 10%	630
	11th to 20th	Night	16% 6% 27% 33% 16% 2	621
	21st to end	Night	11% 4 22% 34% 25% 4	683
June	1st to 10th	Night	6% 2 12% 42% 34% 3	630
	11th to 20th	Night	4 2 12% 45% 33% 4	615
	21st to end	Night	3 1 11% 42% 38% 5%	600
July	1st to 10th	Night	4 2 9% 33% 45% 7%	585
	11th to 20th	Night	3 1 7% 33% 46% 9%	582
	21st to end	Night	5% 1 7% 34% 43% 10%	657
August	1st to 10th	Night	3 1 5% 39% 46% 6%	597
	11th to 20th	Night	5% 1 6% 37% 43% 8%	594
	21st to end	Night	7% 1 7% 33% 45% 7%	660
September	1st to 10th	Night	8% 2 7% 37% 40% 6%	600
	11th to 20th	Night	12% 1 10% 31% 42% 4	600
	21st to end	Night	8% 2 15% 37% 34% 4	710
October	1st to 10th	Night	9% 2 16% 37% 32% 3	800
	11th to 20th	Night	12% 4 26% 38% 20% 1	800
	21st to end	Night	19% 6% 26% 32% 15% 1	880
November	1st to 10th	Night	15% 7% 24% 36% 18% 1	820
	11th to 20th	Night	13% 9% 28% 39% 11%	840
	21st to end	Night	16% 9% 30% 33% 11%	861
December	1st to 10th	Night	21% 7% 32% 33% 6%	1050
	11th to 20th	Night	21% 9% 30% 32% 7%	1050
	21st to end	Night	23% 12% 30% 30% 6%	1155

Page generated at 2026-06-13 01:31:38. Version ac07

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