Washita Battlefield
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Washita Battlefield clear sky chart from 2005-11-06 to 2026-08-15.

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	7% 5% 2 5% 3 3 3 3 5% 7% 58%	152233
	Night	6% 4 1 4 3 3 3 3 5% 7% 59%	147150
Transparency	Day	27% 4 9% 24% 26% 10%	147162
	Night	25% 4 9% 24% 27% 12%	143233
Seeing	Day	9% 9% 30% 32% 18% 3	17828
	Night	9% 9% 36% 35% 11% 1	27645

By Month

Percentage Cloud Cover SW (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	6% 7% 2 5% 4 4 4 3 4 5% 56%	5287
	11th to 20th	Day	3 5% 2 3 2 2 2 2 2 3 72%	5310
	21st to end	Day	11% 7% 2 5% 3 2 3 2 4 5% 56%	5969
February	1st to 10th	Day	6% 8% 3 6% 3 3 3 2 5% 6% 57%	2100
	11th to 20th	Day	6% 6% 2 5% 4 3 3 3 4 5% 59%	2049
	21st to end	Day	5% 5% 2 4 3 3 2 2 4 6% 64%	1730
March	1st to 10th	Day	8% 5% 2 5% 3 3 3 3 4 5% 61%	4658
	11th to 20th	Day	6% 4 2 5% 4 3 3 3 5% 7% 60%	5090
	21st to end	Day	6% 6% 3 6% 4 4 4 3 4 6% 55%	5585
April	1st to 10th	Day	9% 4 1 3 3 3 3 3 5% 7% 60%	2425
	11th to 20th	Day	11% 6% 2 5% 3 4 3 3 4 7% 52%	2491
	21st to end	Day	11% 5% 1 4 4 3 3 3 5% 7% 54%	2697
May	1st to 10th	Day	13% 6% 2 5% 4 4 3 3 4 6% 50%	7655
	11th to 20th	Day	7% 4 1 4 2 3 3 3 5% 7% 61%	7627
	21st to end	Day	13% 7% 2 6% 4 5% 4 3 5% 6% 46%	8404
June	1st to 10th	Day	6% 3 2 5% 4 4 5% 4 7% 8% 51%	2730
	11th to 20th	Day	4 4 1 4 4 3 4 3 6% 8% 58%	2730
	21st to end	Day	5% 3 1 4 3 4 4 4 6% 8% 57%	2730
July	1st to 10th	Day	6% 5% 2 6% 5% 4 5% 5% 7% 9% 45%	7679
	11th to 20th	Day	3 3 1 4 3 4 4 4 6% 9% 57%	7680
	21st to end	Day	2 2 1 3 2 3 4 3 6% 10% 64%	8339
August	1st to 10th	Day	6% 4 2 5% 4 4 3 4 5% 8% 55%	5931
	11th to 20th	Day	3 3 2 5% 4 4 5% 4 6% 10% 54%	5556
	21st to end	Day	10% 4 1 4 3 3 3 4 5% 7% 55%	5984
September	1st to 10th	Day	8% 4 1 5% 4 4 3 2 4 7% 57%	2270
	11th to 20th	Day	8% 4 2 5% 4 4 4 4 5% 8% 52%	2200
	21st to end	Day	6% 2 1 4 4 2 3 3 5% 6% 63%	2200
October	1st to 10th	Day	6% 3 1 3 2 2 2 2 3 5% 73%	3590
	11th to 20th	Day	6% 3 1 3 2 2 3 2 4 6% 69%	3384
	21st to end	Day	6% 3 1 3 2 2 2 2 4 6% 68%	3422
November	1st to 10th	Day	5% 4 1 3 3 2 2 2 4 5% 69%	1853
	11th to 20th	Day	4 4 1 3 3 2 2 2 5% 4 69%	1890
	21st to end	Day	8% 5% 2 4 3 3 2 2 4 5% 62%	1890
December	1st to 10th	Day	4 4 2 4 2 3 3 3 4 6% 67%	3030
	11th to 20th	Day	4 4 1 3 2 3 3 3 4 5% 66%	3481
	21st to end	Day	9% 10% 3 7% 4 4 4 3 5% 4 48%	4587
January	1st to 10th	Night	7% 6% 2 6% 4 4 5% 4 6% 6% 52%	7634
	11th to 20th	Night	2 3 1 3 3 3 3 3 3 5% 72%	7680
	21st to end	Night	11% 9% 2 5% 3 3 3 2 4 5% 53%	8300
February	1st to 10th	Night	8% 7% 2 5% 3 3 4 3 3 5% 57%	2520
	11th to 20th	Night	9% 6% 2 5% 3 3 3 3 4 7% 54%	2458
	21st to end	Night	6% 6% 2 4 3 2 3 3 4 6% 60%	2076
March	1st to 10th	Night	4 6% 2 4 3 3 3 3 4 6% 63%	5431
	11th to 20th	Night	5% 3 1 4 2 3 3 3 4 6% 66%	5090
	21st to end	Night	5% 5% 2 5% 3 3 3 3 6% 7% 57%	5588
April	1st to 10th	Night	6% 5% 1 4 3 3 4 4 5% 7% 59%	2189
	11th to 20th	Night	8% 6% 2 4 2 3 4 3 6% 7% 55%	2077
	21st to end	Night	12% 4 2 3 2 3 3 4 6% 7% 54%	1922
May	1st to 10th	Night	13% 6% 2 5% 3 3 4 3 4 6% 51%	5292
	11th to 20th	Night	6% 3 1 4 3 3 4 3 5% 8% 58%	5265
	21st to end	Night	13% 6% 2 5% 3 3 3 3 5% 7% 49%	5803
June	1st to 10th	Night	4 4 1 4 3 3 5% 5% 8% 10% 53%	1890
	11th to 20th	Night	4 3 1 4 3 3 3 5% 7% 10% 56%	1890
	21st to end	Night	4 3 1 3 3 3 4 4 6% 8% 59%	1890
July	1st to 10th	Night	5% 4 2 5% 4 5% 5% 5% 7% 10% 47%	5310
	11th to 20th	Night	3 2 1 4 4 4 4 4 7% 11% 56%	5310
	21st to end	Night	1 2 1 3 3 3 4 3 6% 9% 64%	5770
August	1st to 10th	Night	3 3 1 3 3 3 4 4 7% 11% 59%	4101
	11th to 20th	Night	3 2 1 4 3 5% 5% 4 8% 13% 50%	4378
	21st to end	Night	11% 5% 1 4 3 3 3 4 5% 8% 53%	4993
September	1st to 10th	Night	7% 3 1 4 3 3 3 3 5% 7% 60%	2129
	11th to 20th	Night	9% 5% 2 4 4 4 4 4 5% 7% 53%	2200
	21st to end	Night	6% 3 2 4 3 3 4 3 4 7% 62%	2200
October	1st to 10th	Night	4 2 1 2 2 2 3 2 4 5% 73%	3590
	11th to 20th	Night	5% 2 1 3 2 3 3 2 3 6% 71%	3720
	21st to end	Night	5% 2 2 2 2 2 2 4 7% 72%	4370
November	1st to 10th	Night	6% 3 1 3 2 2 2 2 4 5% 68%	2665
	11th to 20th	Night	4 3 1 3 2 3 3 2 3 5% 70%	2730
	21st to end	Night	7% 5% 2 3 3 3 3 2 4 6% 62%	2730
December	1st to 10th	Night	4 3 1 3 2 2 3 2 4 6% 69%	4380
	11th to 20th	Night	4 4 1 4 3 3 3 2 4 6% 67%	4946
	21st to end	Night	10% 9% 2 5% 3 3 3 3 4 5% 53%	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	31% 3 6% 26% 24% 10%	5290
	11th to 20th	Day	21% 2 7% 17% 41% 13%	5310
	21st to end	Day	33% 2 4 21% 32% 9%	5969
February	1st to 10th	Day	31% 3 7% 26% 24% 10%	2100
	11th to 20th	Day	29% 3 8% 25% 25% 9%	2059
	21st to end	Day	24% 2 5% 22% 31% 16%	1730
March	1st to 10th	Day	26% 3 6% 14% 23% 28%	4658
	11th to 20th	Day	25% 3 6% 18% 30% 18%	5090
	21st to end	Day	30% 4 9% 30% 22% 4	5585
April	1st to 10th	Day	25% 3 8% 24% 25% 14%	2425
	11th to 20th	Day	33% 4 7% 21% 22% 12%	2494
	21st to end	Day	30% 5% 9% 25% 24% 6%	2697
May	1st to 10th	Day	36% 6% 9% 20% 21% 8%	7655
	11th to 20th	Day	23% 4 7% 24% 29% 12%	7631
	21st to end	Day	39% 6% 9% 19% 13% 13%	8405
June	1st to 10th	Day	28% 8% 16% 28% 14% 7%	2730
	11th to 20th	Day	24% 6% 11% 26% 25% 8%	2730
	21st to end	Day	24% 5% 14% 25% 22% 10%	2730
July	1st to 10th	Day	33% 6% 10% 24% 22% 5%	7616
	11th to 20th	Day	22% 6% 14% 30% 23% 5%	7611
	21st to end	Day	16% 4 13% 34% 29% 3	8155
August	1st to 10th	Day	24% 4 10% 27% 28% 8%	4350
	11th to 20th	Day	22% 6% 9% 26% 29% 8%	4036
	21st to end	Day	21% 4 12% 30% 27% 5%	4311
September	1st to 10th	Day	28% 5% 10% 20% 24% 13%	2270
	11th to 20th	Day	31% 5% 10% 22% 26% 6%	2200
	21st to end	Day	23% 4 9% 22% 31% 11%	2200
October	1st to 10th	Day	17% 2 6% 14% 41% 19%	3590
	11th to 20th	Day	18% 3 9% 24% 26% 20%	3384
	21st to end	Day	19% 3 6% 25% 36% 12%	3422
November	1st to 10th	Day	19% 3 6% 25% 30% 17%	1853
	11th to 20th	Day	20% 2 5% 27% 34% 12%	1890
	21st to end	Day	26% 2 5% 23% 30% 13%	1890
December	1st to 10th	Day	21% 2 7% 36% 28% 6%	3030
	11th to 20th	Day	21% 3 6% 21% 38% 11%	3479
	21st to end	Day	38% 4 7% 22% 20% 9%	4587
January	1st to 10th	Night	31% 3 7% 29% 25% 4	7635
	11th to 20th	Night	16% 3 10% 20% 36% 16%	7680
	21st to end	Night	36% 2 5% 17% 30% 10%	8300
February	1st to 10th	Night	31% 3 6% 21% 26% 12%	2520
	11th to 20th	Night	32% 3 8% 22% 24% 11%	2458
	21st to end	Night	26% 2 5% 22% 26% 19%	2076
March	1st to 10th	Night	23% 4 5% 16% 23% 30%	5431
	11th to 20th	Night	21% 3 6% 19% 24% 27%	5090
	21st to end	Night	27% 4 10% 26% 26% 8%	5588
April	1st to 10th	Night	24% 5% 9% 20% 26% 15%	2189
	11th to 20th	Night	28% 5% 10% 22% 23% 12%	2077
	21st to end	Night	29% 5% 11% 27% 22% 7%	1922
May	1st to 10th	Night	35% 4 11% 19% 21% 10%	5293
	11th to 20th	Night	25% 5% 8% 22% 26% 14%	5266
	21st to end	Night	34% 6% 13% 18% 14% 16%	5805
June	1st to 10th	Night	23% 9% 17% 31% 16% 5%	1890
	11th to 20th	Night	21% 7% 14% 28% 23% 7%	1890
	21st to end	Night	22% 5% 14% 26% 23% 10%	1890
July	1st to 10th	Night	30% 7% 12% 30% 18% 3	5265
	11th to 20th	Night	21% 6% 16% 28% 24% 6%	5256
	21st to end	Night	17% 4 10% 34% 32% 3	5641
August	1st to 10th	Night	19% 5% 12% 26% 29% 9%	3006
	11th to 20th	Night	23% 5% 10% 27% 28% 6%	3174
	21st to end	Night	20% 5% 14% 32% 24% 5%	3597
September	1st to 10th	Night	24% 4 12% 23% 25% 12%	2129
	11th to 20th	Night	31% 5% 9% 20% 27% 8%	2200
	21st to end	Night	23% 5% 7% 23% 30% 12%	2200
October	1st to 10th	Night	16% 3 6% 15% 38% 21%	3590
	11th to 20th	Night	18% 3 6% 21% 35% 17%	3720
	21st to end	Night	15% 2 5% 25% 37% 15%	4370
November	1st to 10th	Night	19% 3 7% 24% 29% 17%	2665
	11th to 20th	Night	18% 3 6% 25% 33% 14%	2730
	21st to end	Night	24% 3 6% 22% 29% 15%	2730
December	1st to 10th	Night	18% 2 6% 37% 31% 6%	4380
	11th to 20th	Night	21% 2 4 23% 38% 12%	4947
	21st to end	Night	33% 4 7% 25% 23% 8%	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	9% 12% 43% 25% 10% 1	330
	11th to 20th	Day	13% 19% 35% 21% 12% 1	330
	21st to end	Day	9% 12% 44% 26% 7% 1	363
February	1st to 10th	Day	8% 15% 45% 23% 8%	330
	11th to 20th	Day	11% 15% 48% 17% 8% 1	330
	21st to end	Day	8% 21% 43% 19% 8% 1	273
March	1st to 10th	Day	8% 18% 46% 22% 6%	330
	11th to 20th	Day	18% 15% 41% 18% 6% 2	330
	21st to end	Day	14% 13% 45% 24% 3 1	363
April	1st to 10th	Day	15% 19% 35% 25% 6%	445
	11th to 20th	Day	13% 23% 45% 17% 2	532
	21st to end	Day	14% 19% 37% 23% 6% 1	717
May	1st to 10th	Day	13% 13% 38% 30% 5% 1	753
	11th to 20th	Day	12% 9% 33% 28% 15% 2	775
	21st to end	Day	12% 8% 35% 29% 13% 2	844
June	1st to 10th	Day	6% 5% 25% 40% 20% 4	780
	11th to 20th	Day	7% 4 32% 39% 18% 2	780
	21st to end	Day	4 4 29% 40% 19% 3	780
July	1st to 10th	Day	8% 2 14% 37% 30% 10%	771
	11th to 20th	Day	2 2 12% 42% 34% 7%	768
	21st to end	Day	3 1 10% 40% 39% 8%	849
August	1st to 10th	Day	5% 1 13% 46% 31% 4	776
	11th to 20th	Day	6% 1 13% 41% 33% 6%	600
	21st to end	Day	7% 1 11% 39% 33% 9%	583
September	1st to 10th	Day	7% 2 12% 41% 31% 7%	400
	11th to 20th	Day	5% 3 17% 42% 26% 6%	330
	21st to end	Day	9% 5% 19% 35% 26% 7%	330
October	1st to 10th	Day	9% 5% 29% 33% 21% 3	330
	11th to 20th	Day	7% 9% 33% 34% 14% 2	330
	21st to end	Day	16% 10% 36% 23% 13% 3	363
November	1st to 10th	Day	9% 10% 35% 33% 10% 2	330
	11th to 20th	Day	8% 15% 33% 28% 13% 3	330
	21st to end	Day	13% 13% 38% 22% 12% 2	330
December	1st to 10th	Day	7% 11% 45% 27% 10% 1	330
	11th to 20th	Day	11% 10% 41% 27% 12% 1	330
	21st to end	Day	14% 18% 37% 21% 10%	363
January	1st to 10th	Night	7% 13% 39% 34% 7%	1050
	11th to 20th	Night	8% 13% 36% 35% 7%	1050
	21st to end	Night	8% 10% 43% 32% 6%	1118
February	1st to 10th	Night	11% 11% 40% 32% 5% 1	840
	11th to 20th	Night	12% 14% 44% 24% 5%	824
	21st to end	Night	10% 16% 44% 26% 4	692
March	1st to 10th	Night	8% 14% 43% 30% 4	816
	11th to 20th	Night	13% 15% 39% 28% 5%	630
	21st to end	Night	11% 15% 46% 25% 3	693
April	1st to 10th	Night	9% 16% 43% 27% 5%	630
	11th to 20th	Night	13% 16% 48% 21% 2	623
	21st to end	Night	14% 13% 42% 26% 4	630
May	1st to 10th	Night	14% 11% 44% 28% 4	630
	11th to 20th	Night	10% 9% 39% 30% 11% 1	621
	21st to end	Night	9% 8% 38% 33% 10% 1	683
June	1st to 10th	Night	6% 5% 35% 40% 13% 1	630
	11th to 20th	Night	4 5% 46% 37% 8%	630
	21st to end	Night	5% 4 34% 44% 12% 1	630
July	1st to 10th	Night	7% 2 20% 46% 23% 1	615
	11th to 20th	Night	4 1 17% 54% 22% 2	612
	21st to end	Night	3 12% 55% 27% 2	690
August	1st to 10th	Night	3 1 20% 52% 23% 1	627
	11th to 20th	Night	7% 1 17% 51% 23%	606
	21st to end	Night	6% 1 15% 44% 31% 2	660
September	1st to 10th	Night	7% 2 19% 48% 23% 1	600
	11th to 20th	Night	12% 3 25% 41% 18% 1	600
	21st to end	Night	8% 3 30% 39% 19% 2	600
October	1st to 10th	Night	8% 6% 28% 42% 15% 1	600
	11th to 20th	Night	9% 9% 38% 37% 7%	686
	21st to end	Night	11% 9% 36% 30% 14%	949
November	1st to 10th	Night	8% 8% 36% 38% 10% 1	1025
	11th to 20th	Night	6% 10% 41% 34% 8%	1050
	21st to end	Night	11% 12% 33% 32% 11%	1050
December	1st to 10th	Night	10% 9% 40% 34% 7% 1	1050
	11th to 20th	Night	11% 11% 43% 30% 6%	1050
	21st to end	Night	11% 13% 38% 31% 6%	1155

Page generated at 2026-08-12 02:37:20. Version ac07

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