Oklahoma City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oklahoma City clear sky chart from 2005-11-06 to 2024-03-28.

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	9% 5% 2 4 4 3 4 4 5% 7% 52%	79202
	Night	9% 5% 2 4 4 2 3 4 5% 7% 56%	80855
Transparency	Day	32% 4 10% 25% 23% 6%	78927
	Night	29% 4 9% 25% 25% 8%	80650
Seeing	Day	14% 13% 31% 28% 12% 2	14449
	Night	12% 13% 36% 28% 9% 1	24539

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	8% 8% 3 7% 6% 3 5% 5% 4 6% 47%	2847
	11th to 20th	Day	8% 5% 2 4 3 2 3 4 4 6% 61%	2850
	21st to end	Day	16% 9% 5% 4 4 2 2 3 3 5% 49%	3135
February	1st to 10th	Day	12% 9% 4 6% 4 3 3 3 3 5% 48%	1793
	11th to 20th	Day	11% 5% 3 6% 4 3 4 3 5% 5% 50%	1849
	21st to end	Day	11% 8% 4 5% 3 2 3 4 4 5% 50%	1570
March	1st to 10th	Day	11% 7% 3 5% 5% 3 3 3 4 7% 50%	2044
	11th to 20th	Day	15% 9% 3 4 4 2 3 3 3 5% 48%	2090
	21st to end	Day	11% 9% 3 5% 4 3 3 4 5% 7% 45%	2255
April	1st to 10th	Day	8% 4 2 5% 5% 3 4 4 5% 6% 54%	1980
	11th to 20th	Day	12% 6% 2 6% 5% 3 4 5% 4 6% 47%	2128
	21st to end	Day	16% 5% 2 5% 4 2 4 4 5% 6% 47%	2340
May	1st to 10th	Day	13% 8% 3 5% 4 2 3 4 5% 7% 46%	2340
	11th to 20th	Day	12% 7% 2 6% 4 2 4 4 5% 7% 47%	2302
	21st to end	Day	10% 6% 3 5% 6% 4 4 6% 6% 8% 40%	2531
June	1st to 10th	Day	6% 4 2 4 5% 3 4 5% 7% 10% 51%	2340
	11th to 20th	Day	6% 3 2 4 5% 3 5% 4 5% 9% 55%	2340
	21st to end	Day	5% 3 1 3 4 3 4 5% 5% 8% 60%	2340
July	1st to 10th	Day	6% 4 2 4 5% 4 6% 6% 6% 11% 47%	2340
	11th to 20th	Day	4 3 1 3 4 3 5% 5% 7% 9% 58%	2340
	21st to end	Day	5% 3 2 3 4 3 5% 6% 7% 10% 51%	2546
August	1st to 10th	Day	3 4 2 3 6% 3 4 6% 6% 8% 54%	2328
	11th to 20th	Day	8% 4 2 5% 4 3 5% 5% 7% 9% 48%	2301
	21st to end	Day	4 2 1 4 4 3 4 5% 6% 10% 56%	2402
September	1st to 10th	Day	10% 3 1 4 4 2 3 3 5% 7% 57%	1980
	11th to 20th	Day	11% 4 2 6% 5% 4 5% 5% 4 7% 48%	1980
	21st to end	Day	7% 4 2 4 4 3 4 4 4 5% 59%	1980
October	1st to 10th	Day	8% 4 2 3 4 2 3 3 4 5% 60%	1947
	11th to 20th	Day	10% 3 1 3 3 2 1 3 3 5% 66%	1800
	21st to end	Day	12% 6% 2 4 3 2 3 3 3 4 58%	1980
November	1st to 10th	Day	8% 4 2 3 3 2 4 4 5% 6% 61%	1778
	11th to 20th	Day	7% 5% 1 3 2 2 3 3 4 5% 66%	1710
	21st to end	Day	12% 6% 2 4 3 2 2 3 4 6% 58%	1710
December	1st to 10th	Day	8% 6% 3 5% 4 3 3 3 4 7% 53%	1710
	11th to 20th	Day	11% 6% 2 5% 5% 3 4 4 4 5% 51%	2161
	21st to end	Day	11% 9% 3 6% 5% 3 4 4 5% 6% 44%	3135
January	1st to 10th	Night	10% 8% 3 6% 5% 2 3 4 4 5% 51%	4108
	11th to 20th	Night	6% 4 2 3 3 2 4 4 5% 7% 60%	4120
	21st to end	Night	16% 8% 3 4 3 1 2 3 3 4 52%	4532
February	1st to 10th	Night	13% 8% 3 5% 4 2 2 3 4 5% 51%	2404
	11th to 20th	Night	12% 6% 2 5% 3 2 3 3 5% 6% 53%	2218
	21st to end	Night	11% 6% 4 5% 4 3 4 4 4 5% 52%	1884
March	1st to 10th	Night	9% 6% 2 5% 5% 3 4 5% 4 6% 53%	2134
	11th to 20th	Night	15% 5% 2 4 3 2 3 3 4 5% 54%	2090
	21st to end	Night	12% 6% 3 6% 4 2 4 4 5% 7% 48%	2255
April	1st to 10th	Night	10% 4 1 4 3 2 3 4 5% 7% 57%	1980
	11th to 20th	Night	13% 4 2 4 3 2 3 4 5% 8% 51%	1777
	21st to end	Night	13% 5% 2 4 3 2 3 3 4 6% 54%	1620
May	1st to 10th	Night	10% 5% 2 5% 5% 2 3 5% 5% 8% 50%	1620
	11th to 20th	Night	11% 5% 2 4 4 3 4 4 6% 6% 50%	1593
	21st to end	Night	7% 3 2 4 4 3 4 4 8% 10% 50%	1745
June	1st to 10th	Night	6% 3 1 2 3 2 3 5% 5% 11% 59%	1620
	11th to 20th	Night	5% 3 2 4 4 2 4 5% 5% 10% 57%	1620
	21st to end	Night	4 2 1 2 2 2 3 4 5% 9% 67%	1620
July	1st to 10th	Night	4 3 2 3 4 3 5% 6% 6% 11% 53%	1620
	11th to 20th	Night	2 2 1 2 3 3 4 5% 6% 9% 62%	1620
	21st to end	Night	4 2 1 3 3 2 3 5% 7% 11% 59%	1772
August	1st to 10th	Night	1 2 1 4 4 2 4 6% 8% 11% 56%	1611
	11th to 20th	Night	4 4 2 4 4 3 5% 5% 7% 8% 54%	1600
	21st to end	Night	2 2 1 3 3 2 4 5% 7% 10% 61%	1947
September	1st to 10th	Night	8% 4 2 3 4 1 4 3 3 7% 61%	1980
	11th to 20th	Night	10% 5% 3 4 5% 2 4 4 4 7% 53%	1980
	21st to end	Night	7% 3 2 3 3 2 3 4 5% 6% 62%	1980
October	1st to 10th	Night	7% 3 1 3 4 3 3 4 5% 6% 61%	1993
	11th to 20th	Night	9% 5% 2 3 3 2 2 3 3 4 64%	2160
	21st to end	Night	12% 5% 2 3 3 2 2 3 3 5% 61%	2376
November	1st to 10th	Night	7% 4 2 3 3 2 2 3 4 5% 66%	2298
	11th to 20th	Night	6% 5% 2 5% 3 3 2 3 3 5% 63%	2470
	21st to end	Night	11% 6% 2 4 3 2 3 3 4 5% 57%	2470
December	1st to 10th	Night	10% 4 2 3 3 3 3 3 4 7% 58%	2470
	11th to 20th	Night	10% 5% 2 5% 5% 3 3 4 4 5% 54%	3036
	21st to end	Night	14% 7% 2 4 3 2 3 4 4 6% 50%	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	38% 5% 7% 23% 23% 4	2848
	11th to 20th	Day	25% 4 11% 26% 28% 6%	2850
	21st to end	Day	41% 3 5% 23% 24% 5%	3135
February	1st to 10th	Day	40% 3 7% 23% 22% 5%	1793
	11th to 20th	Day	36% 3 6% 28% 22% 5%	1859
	21st to end	Day	37% 3 6% 19% 26% 10%	1570
March	1st to 10th	Day	36% 3 7% 22% 20% 12%	2044
	11th to 20th	Day	40% 4 8% 22% 19% 7%	2090
	21st to end	Day	39% 5% 11% 23% 18% 4	2255
April	1st to 10th	Day	31% 4 11% 26% 20% 7%	1980
	11th to 20th	Day	38% 4 9% 21% 19% 8%	2128
	21st to end	Day	38% 5% 8% 26% 21% 3	2340
May	1st to 10th	Day	39% 5% 10% 22% 21% 4	2340
	11th to 20th	Day	37% 5% 12% 29% 16% 2	2306
	21st to end	Day	40% 6% 13% 26% 14% 2	2531
June	1st to 10th	Day	29% 6% 18% 28% 15% 4	2340
	11th to 20th	Day	27% 5% 13% 29% 21% 4	2340
	21st to end	Day	23% 5% 13% 28% 25% 6%	2340
July	1st to 10th	Day	29% 8% 18% 27% 16% 2	2276
	11th to 20th	Day	20% 5% 12% 29% 28% 5%	2271
	21st to end	Day	25% 6% 14% 32% 22% 1	2405
August	1st to 10th	Day	26% 6% 13% 30% 18% 7%	2314
	11th to 20th	Day	31% 5% 14% 27% 20% 3	2301
	21st to end	Day	24% 5% 12% 32% 21% 6%	2402
September	1st to 10th	Day	28% 4 7% 25% 26% 10%	1980
	11th to 20th	Day	36% 5% 8% 22% 24% 6%	1980
	21st to end	Day	27% 3 6% 25% 31% 7%	1980
October	1st to 10th	Day	28% 3 11% 23% 27% 8%	1947
	11th to 20th	Day	24% 3 6% 21% 35% 12%	1800
	21st to end	Day	32% 3 7% 24% 22% 12%	1980
November	1st to 10th	Day	25% 3 7% 25% 30% 10%	1778
	11th to 20th	Day	23% 2 7% 29% 29% 10%	1710
	21st to end	Day	29% 3 6% 26% 26% 10%	1710
December	1st to 10th	Day	31% 4 10% 29% 24% 3	1710
	11th to 20th	Day	36% 3 6% 20% 28% 6%	2159
	21st to end	Day	40% 5% 7% 22% 23% 3	3135
January	1st to 10th	Night	36% 4 6% 23% 25% 6%	4108
	11th to 20th	Night	24% 5% 14% 23% 29% 6%	4120
	21st to end	Night	38% 3 6% 19% 27% 6%	4532
February	1st to 10th	Night	38% 3 7% 22% 23% 7%	2404
	11th to 20th	Night	33% 3 7% 26% 23% 8%	2218
	21st to end	Night	35% 3 5% 19% 25% 13%	1884
March	1st to 10th	Night	34% 3 6% 22% 21% 14%	2134
	11th to 20th	Night	33% 4 7% 26% 21% 8%	2090
	21st to end	Night	36% 5% 10% 25% 18% 5%	2255
April	1st to 10th	Night	28% 3 10% 23% 23% 12%	1980
	11th to 20th	Night	32% 5% 10% 24% 19% 10%	1777
	21st to end	Night	32% 4 11% 26% 23% 4	1620
May	1st to 10th	Night	34% 4 10% 25% 21% 6%	1620
	11th to 20th	Night	33% 5% 13% 26% 19% 4	1594
	21st to end	Night	28% 7% 16% 31% 16% 3	1746
June	1st to 10th	Night	20% 6% 20% 31% 19% 4	1620
	11th to 20th	Night	23% 5% 14% 30% 22% 6%	1620
	21st to end	Night	16% 4 11% 31% 28% 9%	1620
July	1st to 10th	Night	25% 6% 17% 30% 19% 3	1575
	11th to 20th	Night	16% 6% 11% 30% 30% 7%	1566
	21st to end	Night	19% 4 12% 34% 27% 3	1673
August	1st to 10th	Night	19% 5% 15% 30% 25% 6%	1601
	11th to 20th	Night	26% 5% 12% 26% 26% 6%	1600
	21st to end	Night	18% 6% 13% 30% 25% 8%	1947
September	1st to 10th	Night	26% 3 8% 25% 25% 13%	1980
	11th to 20th	Night	34% 4 8% 19% 26% 9%	1980
	21st to end	Night	23% 4 7% 26% 31% 9%	1980
October	1st to 10th	Night	24% 4 11% 22% 27% 12%	1993
	11th to 20th	Night	25% 3 6% 17% 33% 16%	2160
	21st to end	Night	28% 2 6% 24% 27% 13%	2376
November	1st to 10th	Night	22% 3 8% 23% 31% 12%	2298
	11th to 20th	Night	26% 3 6% 24% 30% 11%	2470
	21st to end	Night	31% 3 6% 22% 28% 11%	2470
December	1st to 10th	Night	28% 3 9% 27% 25% 8%	2470
	11th to 20th	Night	34% 3 5% 22% 29% 8%	3037
	21st to end	Night	34% 5% 6% 24% 23% 8%	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	19% 26% 36% 12% 6%	270
	11th to 20th	Day	24% 26% 39% 10% 1	270
	21st to end	Day	16% 28% 37% 15% 3	297
February	1st to 10th	Day	24% 26% 36% 11% 3	270
	11th to 20th	Day	20% 30% 40% 9% 1	270
	21st to end	Day	29% 30% 34% 5% 1	225
March	1st to 10th	Day	21% 27% 39% 11% 1	270
	11th to 20th	Day	31% 23% 35% 10% 1	270
	21st to end	Day	25% 26% 37% 9% 3	285
April	1st to 10th	Day	22% 26% 35% 16% 1	240
	11th to 20th	Day	23% 26% 36% 13% 2	406
	21st to end	Day	22% 23% 32% 15% 7% 1	600
May	1st to 10th	Day	16% 20% 41% 18% 3 1	603
	11th to 20th	Day	17% 14% 35% 23% 10% 1	625
	21st to end	Day	14% 9% 35% 26% 13% 2	679
June	1st to 10th	Day	7% 5% 28% 42% 15% 3	630
	11th to 20th	Day	7% 5% 41% 34% 11% 2	630
	21st to end	Day	4 3 35% 39% 15% 3	630
July	1st to 10th	Day	5% 2 19% 41% 28% 5%	621
	11th to 20th	Day	4 1 19% 51% 21% 4	618
	21st to end	Day	7% 1 14% 46% 26% 5%	684
August	1st to 10th	Day	6% 3 22% 42% 23% 4	626
	11th to 20th	Day	8% 3 22% 40% 23% 3	615
	21st to end	Day	6% 1 17% 44% 28% 5%	521
September	1st to 10th	Day	9% 3 17% 42% 25% 4	270
	11th to 20th	Day	8% 5% 22% 40% 20% 5%	270
	21st to end	Day	13% 6% 27% 36% 15% 3	270
October	1st to 10th	Day	10% 9% 38% 28% 12% 3	270
	11th to 20th	Day	12% 16% 44% 21% 6%	270
	21st to end	Day	23% 19% 33% 18% 6% 1	297
November	1st to 10th	Day	16% 17% 41% 20% 3 2	270
	11th to 20th	Day	18% 20% 36% 21% 4 1	270
	21st to end	Day	23% 26% 33% 15% 3	270
December	1st to 10th	Day	16% 27% 36% 16% 6%	270
	11th to 20th	Day	21% 25% 32% 15% 6%	270
	21st to end	Day	25% 23% 36% 13% 2	297
January	1st to 10th	Night	11% 18% 40% 24% 5% 1	950
	11th to 20th	Night	14% 17% 40% 25% 3	950
	21st to end	Night	12% 19% 37% 27% 5%	1045
February	1st to 10th	Night	19% 19% 38% 21% 3	884
	11th to 20th	Night	18% 20% 40% 19% 3	744
	21st to end	Night	20% 20% 36% 21% 2	628
March	1st to 10th	Night	12% 21% 40% 25% 3	614
	11th to 20th	Night	20% 18% 38% 22% 2	570
	21st to end	Night	19% 21% 38% 18% 4	615
April	1st to 10th	Night	14% 24% 40% 18% 4	540
	11th to 20th	Night	16% 20% 45% 16% 4	533
	21st to end	Night	18% 17% 37% 21% 6% 1	540
May	1st to 10th	Night	11% 16% 46% 21% 6%	540
	11th to 20th	Night	15% 10% 39% 21% 14% 1	531
	21st to end	Night	9% 9% 39% 30% 13% 2	584
June	1st to 10th	Night	8% 4 32% 38% 14% 3	540
	11th to 20th	Night	7% 4 45% 35% 8% 1	540
	21st to end	Night	4 2 41% 38% 15% 1	540
July	1st to 10th	Night	6% 2 25% 43% 22% 2	525
	11th to 20th	Night	2 1 29% 48% 17% 2	522
	21st to end	Night	4 2 18% 55% 19% 2	591
August	1st to 10th	Night	2 3 27% 43% 22% 3	537
	11th to 20th	Night	6% 2 26% 44% 19% 2	534
	21st to end	Night	3 1 22% 44% 28% 3	594
September	1st to 10th	Night	8% 3 27% 40% 21% 1	540
	11th to 20th	Night	12% 3 28% 34% 19% 3	540
	21st to end	Night	9% 5% 35% 32% 16% 4	540
October	1st to 10th	Night	10% 7% 33% 31% 16% 2	553
	11th to 20th	Night	12% 13% 40% 27% 8%	720
	21st to end	Night	16% 13% 36% 24% 10% 1	792
November	1st to 10th	Night	10% 13% 42% 24% 11% 1	818
	11th to 20th	Night	9% 20% 35% 27% 8%	950
	21st to end	Night	16% 18% 33% 27% 7%	950
December	1st to 10th	Night	13% 17% 37% 27% 6%	950
	11th to 20th	Night	17% 18% 38% 22% 5%	950
	21st to end	Night	17% 18% 35% 25% 4	1045

Page generated at 2024-03-24 22:36:59. Version ac07

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