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 2024-10-25.

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 4 3 5% 6% 57%	100966
	Night	7% 5% 2 4 3 3 3 3 5% 7% 58%	98053
Transparency	Day	27% 5% 9% 24% 25% 10%	100733
	Night	25% 5% 10% 24% 26% 11%	97876
Seeing	Day	9% 9% 29% 32% 18% 3	15342
	Night	9% 9% 35% 35% 11% 1	25203

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% 8% 2 5% 4 4 4 3 4 5% 56%	2847
	11th to 20th	Day	5% 5% 2 3 3 3 4 3 4 5% 64%	2850
	21st to end	Day	11% 9% 2 5% 3 2 3 3 4 5% 52%	3208
February	1st to 10th	Day	6% 9% 2 6% 3 3 3 2 5% 5% 56%	1900
	11th to 20th	Day	6% 6% 2 5% 3 3 3 3 4 6% 59%	1849
	21st to end	Day	6% 6% 3 4 4 3 2 3 4 6% 61%	1570
March	1st to 10th	Day	7% 5% 2 4 2 2 3 3 4 5% 63%	3174
	11th to 20th	Day	7% 5% 2 4 4 3 3 3 4 6% 60%	3480
	21st to end	Day	9% 7% 3 7% 4 4 4 3 5% 6% 46%	3814
April	1st to 10th	Day	8% 5% 1 3 3 3 3 3 5% 7% 60%	2194
	11th to 20th	Day	11% 6% 2 6% 3 4 3 3 4 6% 52%	2251
	21st to end	Day	10% 5% 1 4 4 3 4 3 5% 6% 54%	2440
May	1st to 10th	Day	13% 6% 2 5% 4 4 3 3 4 5% 51%	4120
	11th to 20th	Day	10% 5% 2 5% 3 3 4 3 5% 7% 54%	4082
	21st to end	Day	10% 5% 2 4 4 4 4 3 5% 6% 54%	4489
June	1st to 10th	Day	6% 3 2 4 4 3 6% 4 7% 9% 52%	2470
	11th to 20th	Day	4 4 1 4 4 3 4 3 6% 8% 59%	2470
	21st to end	Day	5% 3 1 4 3 4 4 4 6% 7% 59%	2470
July	1st to 10th	Day	7% 4 2 5% 4 4 5% 5% 7% 8% 48%	4120
	11th to 20th	Day	4 3 1 3 4 4 4 4 6% 9% 58%	4120
	21st to end	Day	3 2 1 3 3 3 4 4 6% 9% 61%	4466
August	1st to 10th	Day	5% 3 1 6% 4 3 4 4 5% 8% 57%	4103
	11th to 20th	Day	4 3 1 4 3 4 4 3 5% 9% 59%	3822
	21st to end	Day	4 3 1 3 3 3 3 4 5% 7% 64%	4180
September	1st to 10th	Day	8% 4 1 4 4 4 3 2 4 6% 58%	2157
	11th to 20th	Day	8% 4 2 5% 4 4 4 4 5% 7% 52%	2090
	21st to end	Day	6% 2 1 4 4 2 3 3 5% 6% 64%	2090
October	1st to 10th	Day	10% 4 1 5% 2 2 3 2 3 6% 60%	2090
	11th to 20th	Day	8% 3 1 4 2 2 2 2 3 4 70%	1988
	21st to end	Day	9% 4 2 4 3 2 2 2 2 5% 64%	1963
November	1st to 10th	Day	5% 4 1 3 2 2 2 2 4 5% 68%	1673
	11th to 20th	Day	4 4 2 3 3 2 2 2 5% 5% 69%	1710
	21st to end	Day	9% 5% 2 4 3 3 2 2 4 5% 61%	1710
December	1st to 10th	Day	6% 5% 2 5% 2 3 3 3 4 6% 60%	1710
	11th to 20th	Day	7% 7% 1 5% 3 3 4 3 4 5% 58%	2161
	21st to end	Day	7% 8% 3 8% 4 5% 5% 4 6% 5% 47%	3135
January	1st to 10th	Night	7% 6% 2 6% 4 4 4 3 5% 5% 54%	4108
	11th to 20th	Night	3 4 1 4 3 4 4 4 4 7% 62%	4120
	21st to end	Night	11% 11% 2 4 3 2 2 2 4 5% 53%	4486
February	1st to 10th	Night	8% 8% 2 6% 3 3 4 3 3 5% 55%	2280
	11th to 20th	Night	9% 6% 2 5% 3 3 3 3 4 6% 56%	2218
	21st to end	Night	6% 6% 2 5% 3 2 3 3 5% 7% 58%	1884
March	1st to 10th	Night	4 5% 2 5% 4 3 3 3 4 5% 62%	3686
	11th to 20th	Night	7% 5% 1 4 3 3 3 3 5% 6% 61%	3480
	21st to end	Night	7% 6% 2 6% 4 3 3 3 6% 7% 53%	3817
April	1st to 10th	Night	5% 5% 1 3 3 3 4 4 5% 7% 60%	1981
	11th to 20th	Night	8% 7% 2 4 2 3 4 3 6% 7% 54%	1877
	21st to end	Night	12% 4 2 3 2 3 3 3 6% 7% 56%	1739
May	1st to 10th	Night	15% 7% 2 5% 3 2 3 3 3 4 52%	2850
	11th to 20th	Night	9% 5% 2 6% 4 4 4 4 5% 8% 50%	2823
	21st to end	Night	9% 4 1 4 2 3 3 3 5% 7% 58%	3098
June	1st to 10th	Night	4 3 1 4 3 3 5% 4 8% 10% 55%	1710
	11th to 20th	Night	4 3 1 4 3 3 3 5% 8% 11% 55%	1710
	21st to end	Night	4 3 1 3 3 3 4 4 6% 8% 61%	1710
July	1st to 10th	Night	6% 4 2 5% 3 4 4 4 6% 8% 54%	2850
	11th to 20th	Night	3 2 1 3 3 3 4 4 7% 12% 57%	2850
	21st to end	Night	2 2 1 3 3 3 4 3 6% 9% 63%	3097
August	1st to 10th	Night	2 2 1 4 3 4 4 4 7% 11% 57%	2836
	11th to 20th	Night	4 3 1 4 3 4 4 4 8% 13% 51%	3013
	21st to end	Night	3 2 1 3 3 3 4 4 6% 9% 63%	3487
September	1st to 10th	Night	7% 3 1 4 3 3 3 3 5% 7% 61%	2022
	11th to 20th	Night	10% 5% 2 4 3 4 3 4 5% 7% 53%	2090
	21st to end	Night	6% 3 2 4 3 3 4 3 4 7% 62%	2090
October	1st to 10th	Night	8% 3 1 3 3 3 4 3 6% 5% 60%	2090
	11th to 20th	Night	8% 2 1 3 2 2 2 2 2 5% 71%	2171
	21st to end	Night	8% 3 1 3 2 3 3 2 4 5% 68%	2497
November	1st to 10th	Night	6% 2 1 3 2 2 2 2 5% 6% 68%	2405
	11th to 20th	Night	4 3 1 3 3 3 3 2 3 5% 70%	2470
	21st to end	Night	8% 5% 2 4 3 3 3 3 4 6% 62%	2470
December	1st to 10th	Night	7% 5% 2 3 3 3 3 3 4 5% 62%	2470
	11th to 20th	Night	7% 6% 2 5% 3 3 3 3 5% 6% 57%	3036
	21st to end	Night	8% 8% 2 6% 3 3 4 3 5% 6% 52%	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	30% 5% 8% 21% 28% 7%	2848
	11th to 20th	Day	24% 3 11% 23% 32% 7%	2850
	21st to end	Day	35% 3 5% 23% 28% 5%	3208
February	1st to 10th	Day	32% 3 7% 25% 24% 9%	1900
	11th to 20th	Day	29% 3 7% 26% 25% 10%	1859
	21st to end	Day	26% 3 6% 23% 29% 14%	1570
March	1st to 10th	Day	24% 3 9% 16% 25% 24%	3174
	11th to 20th	Day	26% 4 9% 24% 28% 9%	3480
	21st to end	Day	37% 6% 9% 23% 19% 5%	3814
April	1st to 10th	Day	25% 4 9% 23% 25% 15%	2194
	11th to 20th	Day	34% 4 7% 21% 22% 12%	2254
	21st to end	Day	30% 5% 10% 25% 24% 6%	2440
May	1st to 10th	Day	34% 7% 10% 16% 21% 12%	4120
	11th to 20th	Day	29% 6% 11% 28% 20% 6%	4086
	21st to end	Day	30% 7% 9% 19% 19% 16%	4489
June	1st to 10th	Day	27% 8% 16% 28% 14% 8%	2470
	11th to 20th	Day	24% 6% 11% 26% 24% 9%	2470
	21st to end	Day	22% 5% 13% 25% 23% 11%	2470
July	1st to 10th	Day	31% 6% 10% 28% 19% 5%	4056
	11th to 20th	Day	21% 6% 10% 31% 26% 6%	4051
	21st to end	Day	18% 6% 11% 31% 30% 4	4325
August	1st to 10th	Day	25% 4 10% 26% 28% 7%	4090
	11th to 20th	Day	22% 6% 9% 26% 29% 9%	3861
	21st to end	Day	20% 4 12% 31% 28% 5%	4179
September	1st to 10th	Day	28% 5% 9% 21% 23% 14%	2157
	11th to 20th	Day	31% 5% 9% 21% 27% 6%	2090
	21st to end	Day	22% 4 9% 22% 32% 11%	2090
October	1st to 10th	Day	27% 4 10% 20% 28% 11%	2090
	11th to 20th	Day	21% 3 7% 19% 31% 20%	1988
	21st to end	Day	25% 3 6% 23% 28% 14%	1963
November	1st to 10th	Day	19% 3 6% 25% 30% 17%	1673
	11th to 20th	Day	19% 2 5% 28% 34% 11%	1710
	21st to end	Day	27% 3 4 21% 31% 14%	1710
December	1st to 10th	Day	26% 3 10% 26% 27% 7%	1710
	11th to 20th	Day	30% 4 9% 17% 30% 10%	2159
	21st to end	Day	36% 6% 8% 19% 23% 8%	3135
January	1st to 10th	Night	30% 4 9% 25% 26% 5%	4108
	11th to 20th	Night	22% 4 15% 22% 29% 8%	4120
	21st to end	Night	35% 4 6% 20% 27% 8%	4486
February	1st to 10th	Night	33% 3 7% 21% 26% 10%	2280
	11th to 20th	Night	31% 3 7% 21% 26% 11%	2218
	21st to end	Night	27% 2 6% 22% 26% 17%	1884
March	1st to 10th	Night	23% 5% 6% 19% 22% 24%	3686
	11th to 20th	Night	24% 4 9% 26% 25% 12%	3480
	21st to end	Night	30% 5% 10% 24% 21% 9%	3817
April	1st to 10th	Night	23% 5% 9% 20% 26% 17%	1981
	11th to 20th	Night	29% 5% 10% 21% 23% 11%	1877
	21st to end	Night	28% 5% 10% 27% 23% 8%	1739
May	1st to 10th	Night	36% 5% 8% 16% 20% 16%	2850
	11th to 20th	Night	31% 7% 13% 25% 17% 6%	2824
	21st to end	Night	26% 6% 11% 18% 18% 22%	3099
June	1st to 10th	Night	21% 9% 17% 32% 16% 5%	1710
	11th to 20th	Night	21% 7% 14% 26% 24% 7%	1710
	21st to end	Night	20% 5% 13% 26% 24% 11%	1710
July	1st to 10th	Night	27% 5% 11% 34% 20% 3	2805
	11th to 20th	Night	18% 5% 12% 29% 30% 7%	2796
	21st to end	Night	17% 4 12% 28% 33% 5%	2999
August	1st to 10th	Night	19% 5% 12% 25% 30% 9%	2826
	11th to 20th	Night	24% 5% 10% 27% 28% 7%	3040
	21st to end	Night	19% 5% 14% 33% 25% 5%	3487
September	1st to 10th	Night	23% 4 12% 23% 25% 12%	2022
	11th to 20th	Night	31% 5% 9% 19% 28% 8%	2090
	21st to end	Night	22% 5% 7% 23% 30% 12%	2090
October	1st to 10th	Night	25% 5% 10% 19% 30% 12%	2090
	11th to 20th	Night	20% 2 5% 19% 34% 20%	2171
	21st to end	Night	21% 3 6% 24% 29% 17%	2497
November	1st to 10th	Night	19% 3 7% 24% 29% 17%	2405
	11th to 20th	Night	19% 3 6% 26% 32% 14%	2470
	21st to end	Night	25% 3 6% 20% 30% 16%	2470
December	1st to 10th	Night	25% 3 9% 24% 28% 10%	2470
	11th to 20th	Night	29% 3 6% 21% 32% 9%	3037
	21st to end	Night	32% 5% 9% 20% 25% 9%	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	9% 13% 43% 24% 10% 1	270
	11th to 20th	Day	14% 19% 34% 22% 10%	270
	21st to end	Day	8% 13% 45% 26% 7% 1	297
February	1st to 10th	Day	10% 16% 45% 23% 6%	270
	11th to 20th	Day	11% 12% 51% 17% 7% 1	270
	21st to end	Day	10% 22% 44% 18% 5%	225
March	1st to 10th	Day	7% 15% 48% 24% 6%	270
	11th to 20th	Day	17% 16% 41% 18% 6% 2	270
	21st to end	Day	16% 15% 44% 21% 3	297
April	1st to 10th	Day	14% 20% 37% 24% 5%	374
	11th to 20th	Day	13% 23% 44% 18% 2	452
	21st to end	Day	13% 20% 36% 24% 7% 1	620
May	1st to 10th	Day	12% 13% 40% 29% 5% 1	653
	11th to 20th	Day	12% 8% 32% 29% 17% 2	675
	21st to end	Day	11% 8% 37% 29% 14% 2	734
June	1st to 10th	Day	6% 5% 25% 39% 21% 5%	680
	11th to 20th	Day	6% 3 32% 39% 18% 1	680
	21st to end	Day	3 4 27% 42% 21% 4	680
July	1st to 10th	Day	9% 1 13% 37% 31% 10%	671
	11th to 20th	Day	3 2 12% 43% 33% 6%	668
	21st to end	Day	4 1 9% 40% 39% 8%	739
August	1st to 10th	Day	5% 1 12% 45% 33% 4	676
	11th to 20th	Day	7% 1 13% 42% 34% 5%	537
	21st to end	Day	5% 1 12% 40% 34% 9%	539
September	1st to 10th	Day	7% 2 11% 40% 32% 7%	367
	11th to 20th	Day	5% 3 16% 44% 25% 7%	300
	21st to end	Day	9% 5% 19% 33% 26% 7%	300
October	1st to 10th	Day	10% 5% 30% 32% 20% 3	300
	11th to 20th	Day	7% 9% 32% 35% 14% 3	300
	21st to end	Day	16% 9% 37% 23% 13% 3	311
November	1st to 10th	Day	9% 9% 34% 35% 11% 2	270
	11th to 20th	Day	8% 14% 34% 27% 13% 3	270
	21st to end	Day	16% 13% 36% 22% 12% 2	270
December	1st to 10th	Day	7% 12% 44% 26% 10% 1	270
	11th to 20th	Day	12% 10% 40% 27% 10% 1	270
	21st to end	Day	15% 19% 39% 21% 6%	297
January	1st to 10th	Night	7% 13% 39% 35% 7%	950
	11th to 20th	Night	9% 13% 35% 35% 8%	950
	21st to end	Night	8% 10% 42% 33% 6%	1012
February	1st to 10th	Night	12% 12% 40% 30% 5% 1	760
	11th to 20th	Night	11% 13% 45% 25% 6%	744
	21st to end	Night	11% 17% 43% 25% 4	628
March	1st to 10th	Night	8% 13% 44% 30% 4	738
	11th to 20th	Night	14% 14% 39% 29% 5%	570
	21st to end	Night	12% 15% 45% 24% 4	627
April	1st to 10th	Night	8% 16% 44% 26% 5%	570
	11th to 20th	Night	12% 15% 50% 21% 2	563
	21st to end	Night	14% 12% 41% 27% 5%	570
May	1st to 10th	Night	15% 11% 44% 28% 4	570
	11th to 20th	Night	10% 7% 39% 31% 11% 1	561
	21st to end	Night	8% 8% 39% 33% 11% 1	617
June	1st to 10th	Night	5% 5% 35% 41% 14% 1	570
	11th to 20th	Night	4 5% 47% 37% 7%	570
	21st to end	Night	5% 3 32% 46% 13% 1	570
July	1st to 10th	Night	7% 2 20% 46% 24% 1	555
	11th to 20th	Night	4 18% 53% 22% 2	552
	21st to end	Night	4 12% 55% 28% 2	624
August	1st to 10th	Night	3 1 17% 52% 25% 1	567
	11th to 20th	Night	7% 1 17% 51% 24%	564
	21st to end	Night	5% 1 15% 45% 31% 3	627
September	1st to 10th	Night	8% 2 18% 48% 24% 1	570
	11th to 20th	Night	13% 3 25% 40% 18% 1	570
	21st to end	Night	8% 3 31% 38% 19% 2	570
October	1st to 10th	Night	8% 6% 28% 42% 16% 1	570
	11th to 20th	Night	10% 8% 38% 37% 7%	651
	21st to end	Night	11% 8% 36% 30% 14%	873
November	1st to 10th	Night	7% 8% 36% 38% 10% 1	925
	11th to 20th	Night	6% 10% 43% 33% 8%	950
	21st to end	Night	11% 12% 33% 33% 10% 1	950
December	1st to 10th	Night	10% 9% 39% 33% 7% 1	950
	11th to 20th	Night	12% 11% 42% 30% 6%	950
	21st to end	Night	11% 14% 38% 30% 6%	1045

Page generated at 2024-10-22 19:21:06. Version ac07

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