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 2024-03-01.

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 4 4 2 4 4 5% 7% 57%	78907
	Night	7% 4 2 4 4 2 3 4 5% 7% 58%	80571
Transparency	Day	28% 5% 10% 24% 25% 9%	78635
	Night	26% 5% 10% 23% 26% 10%	80366
Seeing	Day	9% 9% 29% 32% 18% 3	14360
	Night	9% 9% 35% 35% 11% 1	24470

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 4 5% 3 4 4 4 5% 56%	2847
	11th to 20th	Day	5% 4 2 3 3 2 4 4 3 5% 64%	2850
	21st to end	Day	12% 9% 2 4 4 2 3 3 4 5% 52%	3208
February	1st to 10th	Day	6% 8% 3 5% 4 2 3 3 4 6% 56%	1900
	11th to 20th	Day	6% 5% 3 5% 4 2 3 3 4 6% 59%	1849
	21st to end	Day	6% 5% 3 4 4 2 3 3 4 6% 61%	1570
March	1st to 10th	Day	7% 6% 3 5% 4 3 4 5% 5% 6% 52%	1818
	11th to 20th	Day	11% 5% 2 4 5% 2 2 3 4 6% 57%	1980
	21st to end	Day	8% 5% 3 5% 4 3 4 4 5% 6% 54%	2178
April	1st to 10th	Day	8% 4 1 3 3 2 3 3 5% 7% 61%	2078
	11th to 20th	Day	11% 5% 2 5% 4 3 4 4 4 7% 51%	2131
	21st to end	Day	10% 5% 1 4 4 2 4 3 5% 7% 54%	2311
May	1st to 10th	Day	10% 5% 3 4 5% 3 4 4 5% 6% 52%	2340
	11th to 20th	Day	10% 4 2 4 4 3 4 3 5% 8% 53%	2302
	21st to end	Day	10% 4 2 4 5% 4 5% 5% 5% 8% 48%	2531
June	1st to 10th	Day	6% 3 2 4 4 2 5% 5% 7% 8% 53%	2340
	11th to 20th	Day	4 4 2 3 4 3 3 4 6% 8% 59%	2340
	21st to end	Day	5% 3 1 3 4 2 4 5% 6% 7% 60%	2340
July	1st to 10th	Day	6% 4 2 4 5% 3 6% 6% 6% 9% 49%	2340
	11th to 20th	Day	4 3 1 3 4 3 4 5% 6% 9% 59%	2340
	21st to end	Day	3 3 1 3 4 3 5% 5% 6% 9% 58%	2546
August	1st to 10th	Day	3 2 1 5% 5% 3 5% 6% 6% 9% 56%	2328
	11th to 20th	Day	7% 4 2 4 5% 4 5% 4 6% 9% 50%	2180
	21st to end	Day	4 3 1 2 5% 3 4 6% 6% 8% 57%	2376
September	1st to 10th	Day	8% 4 2 4 4 3 3 3 4 6% 59%	2044
	11th to 20th	Day	9% 4 2 5% 5% 3 4 5% 5% 7% 52%	1980
	21st to end	Day	6% 2 1 4 5% 1 3 4 5% 6% 63%	1980
October	1st to 10th	Day	11% 4 1 5% 3 2 3 3 3 7% 58%	1980
	11th to 20th	Day	8% 3 1 3 3 2 2 2 3 4 70%	1884
	21st to end	Day	9% 4 2 4 3 1 2 3 3 6% 63%	1917
November	1st to 10th	Day	5% 4 1 3 3 1 2 3 4 6% 69%	1673
	11th to 20th	Day	4 4 2 3 3 1 2 2 5% 5% 70%	1710
	21st to end	Day	9% 5% 2 3 3 2 2 3 4 5% 61%	1710
December	1st to 10th	Day	6% 5% 2 5% 3 2 3 4 5% 6% 60%	1710
	11th to 20th	Day	7% 6% 2 4 4 2 4 4 4 5% 58%	2161
	21st to end	Day	7% 7% 3 7% 5% 3 5% 4 6% 5% 47%	3135
January	1st to 10th	Night	8% 6% 2 5% 5% 3 4 4 5% 5% 54%	4108
	11th to 20th	Night	3 3 1 4 4 3 4 5% 4 7% 62%	4120
	21st to end	Night	11% 11% 2 4 3 2 2 3 4 5% 53%	4486
February	1st to 10th	Night	8% 8% 3 4 4 2 4 4 3 5% 56%	2280
	11th to 20th	Night	9% 5% 2 4 3 3 3 4 4 6% 56%	2218
	21st to end	Night	7% 6% 2 4 3 2 3 4 4 7% 58%	1884
March	1st to 10th	Night	5% 4 2 4 5% 3 4 5% 6% 7% 56%	2146
	11th to 20th	Night	12% 5% 2 4 3 2 3 4 4 5% 56%	1980
	21st to end	Night	8% 5% 2 4 4 3 3 3 5% 7% 56%	2178
April	1st to 10th	Night	5% 4 1 3 4 2 4 5% 5% 7% 60%	1877
	11th to 20th	Night	8% 7% 2 4 3 2 4 4 6% 8% 53%	1777
	21st to end	Night	12% 4 2 3 3 2 3 4 5% 7% 55%	1648
May	1st to 10th	Night	10% 6% 2 4 4 2 3 4 4 7% 54%	1620
	11th to 20th	Night	8% 4 2 4 5% 2 4 5% 5% 8% 53%	1593
	21st to end	Night	8% 3 2 5% 4 2 5% 5% 7% 10% 51%	1745
June	1st to 10th	Night	4 3 1 3 3 2 4 5% 7% 11% 55%	1620
	11th to 20th	Night	5% 2 1 3 3 3 4 6% 7% 11% 56%	1620
	21st to end	Night	5% 2 2 3 3 2 4 4 6% 8% 62%	1620
July	1st to 10th	Night	6% 4 1 5% 4 3 4 4 6% 9% 55%	1620
	11th to 20th	Night	4 1 1 3 3 2 3 5% 6% 10% 62%	1620
	21st to end	Night	3 2 1 3 4 2 3 4 7% 10% 61%	1772
August	1st to 10th	Night	2 2 2 4 4 2 5% 6% 6% 10% 56%	1611
	11th to 20th	Night	6% 3 1 4 4 3 4 5% 6% 10% 52%	1717
	21st to end	Night	4 2 1 4 4 2 4 6% 7% 10% 56%	1980
September	1st to 10th	Night	7% 2 1 3 4 2 3 4 5% 8% 61%	1915
	11th to 20th	Night	10% 5% 2 3 4 3 4 4 5% 7% 53%	1980
	21st to end	Night	5% 3 2 4 4 2 3 4 4 7% 62%	1980
October	1st to 10th	Night	8% 3 1 3 4 2 4 4 6% 6% 59%	1980
	11th to 20th	Night	9% 3 1 2 2 2 2 2 2 5% 71%	2056
	21st to end	Night	8% 3 1 3 3 2 3 2 4 5% 68%	2437
November	1st to 10th	Night	6% 2 1 3 3 2 2 3 4 6% 68%	2405
	11th to 20th	Night	4 3 1 3 3 2 3 3 3 5% 70%	2470
	21st to end	Night	8% 4 2 3 3 2 3 3 3 6% 62%	2470
December	1st to 10th	Night	7% 4 2 3 3 2 3 3 4 6% 62%	2470
	11th to 20th	Night	7% 6% 2 5% 4 2 3 4 5% 6% 57%	3036
	21st to end	Night	8% 7% 2 5% 4 2 4 5% 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% 22% 29% 14%	1570
March	1st to 10th	Day	32% 3 9% 20% 21% 15%	1818
	11th to 20th	Day	31% 3 8% 24% 22% 11%	1980
	21st to end	Day	31% 4 10% 24% 22% 9%	2178
April	1st to 10th	Day	25% 4 9% 23% 25% 14%	2078
	11th to 20th	Day	34% 5% 7% 21% 22% 11%	2134
	21st to end	Day	30% 5% 10% 24% 25% 6%	2311
May	1st to 10th	Day	34% 6% 10% 17% 22% 12%	2340
	11th to 20th	Day	30% 6% 12% 27% 21% 4	2306
	21st to end	Day	34% 8% 12% 25% 15% 6%	2531
June	1st to 10th	Day	27% 8% 15% 28% 14% 8%	2340
	11th to 20th	Day	23% 6% 11% 26% 24% 10%	2340
	21st to end	Day	22% 5% 13% 25% 24% 12%	2340
July	1st to 10th	Day	29% 8% 13% 27% 19% 4	2276
	11th to 20th	Day	20% 7% 11% 25% 29% 8%	2271
	21st to end	Day	22% 6% 13% 32% 24% 3	2405
August	1st to 10th	Day	23% 6% 13% 32% 21% 6%	2314
	11th to 20th	Day	29% 8% 14% 25% 19% 5%	2180
	21st to end	Day	24% 6% 12% 27% 22% 8%	2376
September	1st to 10th	Day	27% 5% 10% 21% 23% 14%	2044
	11th to 20th	Day	32% 5% 10% 20% 27% 6%	1980
	21st to end	Day	22% 4 9% 22% 32% 10%	1980
October	1st to 10th	Day	29% 4 10% 21% 26% 10%	1980
	11th to 20th	Day	21% 2 6% 19% 31% 20%	1884
	21st to end	Day	26% 4 6% 23% 27% 14%	1917
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	27% 4 8% 22% 25% 14%	2146
	11th to 20th	Night	30% 4 7% 24% 23% 12%	1980
	21st to end	Night	29% 4 12% 26% 21% 8%	2178
April	1st to 10th	Night	23% 5% 9% 21% 26% 16%	1877
	11th to 20th	Night	30% 5% 10% 22% 23% 10%	1777
	21st to end	Night	28% 5% 10% 26% 23% 8%	1648
May	1st to 10th	Night	32% 5% 10% 17% 25% 11%	1620
	11th to 20th	Night	30% 7% 14% 22% 19% 8%	1594
	21st to end	Night	27% 7% 16% 25% 18% 7%	1746
June	1st to 10th	Night	21% 9% 16% 32% 16% 6%	1620
	11th to 20th	Night	21% 8% 14% 26% 24% 7%	1620
	21st to end	Night	20% 5% 13% 25% 26% 11%	1620
July	1st to 10th	Night	26% 6% 15% 29% 19% 5%	1575
	11th to 20th	Night	17% 5% 11% 24% 31% 11%	1566
	21st to end	Night	17% 5% 13% 30% 29% 5%	1673
August	1st to 10th	Night	21% 7% 14% 28% 23% 8%	1601
	11th to 20th	Night	27% 5% 15% 23% 23% 6%	1717
	21st to end	Night	22% 7% 14% 25% 23% 9%	1980
September	1st to 10th	Night	23% 4 12% 24% 25% 12%	1915
	11th to 20th	Night	32% 6% 10% 18% 28% 8%	1980
	21st to end	Night	22% 6% 7% 23% 30% 12%	1980
October	1st to 10th	Night	26% 5% 11% 19% 29% 11%	1980
	11th to 20th	Night	20% 2 5% 19% 34% 20%	2056
	21st to end	Night	21% 3 6% 24% 29% 17%	2437
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% 23% 44% 17% 5%	225
March	1st to 10th	Day	7% 16% 50% 20% 7%	240
	11th to 20th	Day	18% 18% 39% 17% 6% 2	240
	21st to end	Day	16% 14% 45% 21% 4	264
April	1st to 10th	Day	13% 20% 37% 25% 6%	338
	11th to 20th	Day	14% 23% 42% 19% 2	412
	21st to end	Day	13% 19% 36% 23% 6% 1	571
May	1st to 10th	Day	12% 12% 39% 30% 5% 1	603
	11th to 20th	Day	13% 8% 32% 30% 16% 2	625
	21st to end	Day	12% 8% 35% 29% 14% 2	679
June	1st to 10th	Day	6% 4 25% 39% 21% 5%	630
	11th to 20th	Day	6% 3 31% 39% 19% 2	630
	21st to end	Day	3 4 27% 40% 22% 4	630
July	1st to 10th	Day	8% 1 12% 37% 32% 11%	621
	11th to 20th	Day	3 2 12% 42% 35% 7%	618
	21st to end	Day	4 1 8% 39% 40% 8%	684
August	1st to 10th	Day	4 2 12% 46% 32% 4	626
	11th to 20th	Day	7% 1 13% 41% 33% 4	494
	21st to end	Day	5% 1 12% 40% 33% 9%	495
September	1st to 10th	Day	7% 3 11% 39% 34% 7%	334
	11th to 20th	Day	6% 2 15% 43% 27% 8%	270
	21st to end	Day	9% 5% 21% 32% 27% 6%	270
October	1st to 10th	Day	11% 6% 30% 33% 17% 4	270
	11th to 20th	Day	7% 9% 34% 34% 14% 2	270
	21st to end	Day	16% 9% 38% 23% 12% 3	297
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% 14% 44% 30% 5%	702
	11th to 20th	Night	15% 13% 38% 28% 5%	540
	21st to end	Night	12% 15% 46% 24% 4	594
April	1st to 10th	Night	8% 15% 44% 27% 5%	540
	11th to 20th	Night	13% 16% 49% 20% 2	533
	21st to end	Night	14% 12% 41% 27% 5%	540
May	1st to 10th	Night	13% 10% 44% 29% 4	540
	11th to 20th	Night	10% 7% 40% 30% 12% 1	531
	21st to end	Night	8% 7% 40% 33% 11% 1	584
June	1st to 10th	Night	6% 5% 34% 41% 14% 1	540
	11th to 20th	Night	4 5% 46% 38% 7%	540
	21st to end	Night	5% 3 32% 46% 14% 1	540
July	1st to 10th	Night	7% 1 19% 46% 25% 2	525
	11th to 20th	Night	4 16% 53% 23% 2	522
	21st to end	Night	4 11% 54% 29% 2	591
August	1st to 10th	Night	4 1 17% 52% 25% 1	537
	11th to 20th	Night	7% 1 16% 51% 24%	534
	21st to end	Night	5% 1 15% 45% 32% 3	594
September	1st to 10th	Night	8% 1 19% 48% 24% 1	540
	11th to 20th	Night	13% 2 25% 40% 19% 1	540
	21st to end	Night	8% 3 31% 39% 18% 2	540
October	1st to 10th	Night	9% 6% 28% 42% 14% 1	540
	11th to 20th	Night	10% 9% 38% 36% 7%	616
	21st to end	Night	11% 8% 36% 30% 15%	853
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 2024-02-27 05:30:18. Version ac07

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