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 2025-09-04.

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% 6% 2 5% 3 3 4 3 5% 7% 53%	126164
	Night	9% 5% 2 4 3 3 3 3 5% 7% 57%	122849
Transparency	Day	31% 5% 10% 25% 23% 7%	129881
	Night	27% 4 9% 25% 26% 9%	127195
Seeing	Day	14% 13% 31% 28% 12% 2	16557
	Night	12% 13% 36% 28% 9% 1	26351

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	11% 7% 3 9% 4 3 4 3 4 5% 47%	4077
	11th to 20th	Day	6% 5% 2 5% 2 3 2 3 4 5% 64%	4080
	21st to end	Day	14% 8% 4 5% 3 2 2 2 3 4 53%	4488
February	1st to 10th	Day	12% 10% 3 7% 3 4 2 3 3 5% 48%	1888
	11th to 20th	Day	11% 6% 2 7% 4 4 3 3 5% 5% 49%	1949
	21st to end	Day	11% 8% 4 5% 3 3 3 3 4 5% 51%	1650
March	1st to 10th	Day	10% 6% 2 5% 3 3 3 2 4 5% 58%	4843
	11th to 20th	Day	7% 7% 2 5% 4 4 4 3 5% 6% 55%	4980
	21st to end	Day	11% 10% 3 6% 4 3 4 3 5% 7% 43%	5462
April	1st to 10th	Day	10% 5% 2 6% 4 4 4 3 5% 6% 53%	2200
	11th to 20th	Day	12% 6% 2 7% 4 4 4 4 5% 5% 48%	2369
	21st to end	Day	16% 5% 2 6% 3 4 4 4 5% 6% 46%	2600
May	1st to 10th	Day	18% 9% 2 5% 4 3 4 3 5% 5% 41%	5862
	11th to 20th	Day	9% 5% 2 6% 3 4 4 3 5% 7% 52%	5862
	21st to end	Day	13% 7% 3 7% 4 5% 4 4 5% 6% 41%	6434
June	1st to 10th	Day	6% 5% 2 5% 4 3 5% 4 7% 10% 49%	2600
	11th to 20th	Day	6% 4 1 5% 4 4 5% 3 5% 10% 54%	2600
	21st to end	Day	4 3 1 3 4 4 4 4 5% 8% 60%	2600
July	1st to 10th	Day	10% 5% 2 6% 5% 5% 5% 4 6% 9% 43%	5900
	11th to 20th	Day	6% 4 1 4 4 3 4 4 6% 9% 55%	5900
	21st to end	Day	3 2 1 3 3 3 4 4 6% 9% 62%	6422
August	1st to 10th	Day	5% 3 2 4 4 4 4 4 6% 9% 56%	4234
	11th to 20th	Day	7% 3 1 5% 3 4 4 3 6% 9% 55%	4171
	21st to end	Day	5% 3 1 4 3 4 4 3 5% 8% 61%	4353
September	1st to 10th	Day	10% 4 1 5% 4 3 4 2 5% 6% 56%	2123
	11th to 20th	Day	11% 4 2 7% 4 5% 5% 4 4 7% 49%	2090
	21st to end	Day	7% 4 1 5% 3 4 4 3 4 5% 59%	2090
October	1st to 10th	Day	8% 4 2 4 3 3 3 3 4 5% 62%	2055
	11th to 20th	Day	10% 3 1 3 2 2 2 2 3 4 67%	1900
	21st to end	Day	11% 6% 2 4 3 3 3 3 3 4 59%	2090
November	1st to 10th	Day	8% 4 2 3 2 3 4 3 5% 6% 59%	1873
	11th to 20th	Day	7% 5% 1 3 2 2 3 3 4 5% 65%	1800
	21st to end	Day	11% 6% 1 4 2 2 2 2 5% 5% 59%	1800
December	1st to 10th	Day	6% 6% 2 5% 3 3 3 3 5% 7% 58%	2940
	11th to 20th	Day	8% 5% 2 5% 3 3 3 3 5% 6% 59%	3391
	21st to end	Day	15% 11% 3 6% 4 3 3 3 4 5% 44%	4488
January	1st to 10th	Night	12% 7% 3 7% 3 3 3 3 5% 5% 49%	5888
	11th to 20th	Night	4 3 2 4 3 3 3 3 5% 7% 64%	5900
	21st to end	Night	14% 8% 3 5% 2 2 2 2 3 5% 53%	6490
February	1st to 10th	Night	13% 8% 3 6% 3 3 2 2 4 4 52%	2530
	11th to 20th	Night	12% 7% 2 5% 3 3 3 2 5% 6% 51%	2338
	21st to end	Night	10% 6% 3 5% 3 4 3 3 4 5% 53%	1980
March	1st to 10th	Night	10% 6% 2 5% 3 3 3 2 4 5% 57%	5013
	11th to 20th	Night	7% 3 1 4 2 3 3 3 4 6% 64%	4980
	21st to end	Night	10% 7% 2 6% 3 3 5% 3 5% 8% 47%	5467
April	1st to 10th	Night	10% 4 1 4 3 3 3 3 5% 7% 56%	2200
	11th to 20th	Night	12% 5% 2 4 2 3 3 3 6% 7% 52%	1976
	21st to end	Night	14% 5% 2 5% 3 3 3 3 4 7% 52%	1800
May	1st to 10th	Night	18% 7% 2 5% 4 3 3 3 4 6% 47%	4053
	11th to 20th	Night	10% 4 2 4 3 4 4 3 5% 7% 55%	4053
	21st to end	Night	11% 4 2 5% 3 3 4 4 6% 7% 51%	4443
June	1st to 10th	Night	6% 4 1 3 2 4 4 3 6% 11% 57%	1800
	11th to 20th	Night	5% 3 1 4 4 4 4 4 5% 10% 56%	1800
	21st to end	Night	3 2 1 2 2 2 3 3 6% 9% 66%	1800
July	1st to 10th	Night	6% 4 2 5% 4 4 5% 5% 7% 10% 49%	4078
	11th to 20th	Night	4 2 1 3 3 3 4 4 6% 10% 62%	4077
	21st to end	Night	4 2 1 3 2 2 3 3 5% 9% 66%	4449
August	1st to 10th	Night	1 2 1 3 3 3 3 4 6% 10% 64%	2926
	11th to 20th	Night	5% 3 2 4 3 4 5% 4 7% 9% 56%	2888
	21st to end	Night	3 2 1 3 2 2 3 3 6% 10% 65%	3546
September	1st to 10th	Night	7% 5% 1 4 3 2 4 2 4 6% 61%	2123
	11th to 20th	Night	10% 5% 3 5% 3 3 4 3 4 7% 54%	2090
	21st to end	Night	7% 3 2 4 3 3 3 3 5% 6% 62%	2090
October	1st to 10th	Night	7% 3 1 4 4 3 3 3 5% 6% 62%	2104
	11th to 20th	Night	9% 5% 2 3 2 2 2 2 4 4 65%	2280
	21st to end	Night	11% 4 2 3 2 2 2 2 3 5% 62%	2508
November	1st to 10th	Night	8% 4 2 3 3 2 2 2 4 5% 65%	2423
	11th to 20th	Night	6% 5% 2 5% 3 3 2 2 4 5% 63%	2600
	21st to end	Night	10% 6% 2 4 3 3 3 2 4 5% 58%	2600
December	1st to 10th	Night	6% 5% 2 4 2 3 2 2 4 6% 63%	4250
	11th to 20th	Night	10% 4 2 5% 3 3 3 3 3 5% 58%	4816
	21st to end	Night	15% 8% 2 4 3 3 3 3 3 5% 51%	6490

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% 9% 25% 20% 3	4078
	11th to 20th	Day	24% 3 8% 21% 35% 8%	4080
	21st to end	Day	38% 2 4 20% 29% 7%	4488
February	1st to 10th	Day	40% 3 7% 22% 22% 5%	1888
	11th to 20th	Day	37% 3 7% 27% 21% 5%	1959
	21st to end	Day	36% 3 5% 18% 27% 11%	1650
March	1st to 10th	Day	31% 3 5% 16% 22% 23%	4843
	11th to 20th	Day	30% 4 7% 18% 23% 17%	4980
	21st to end	Day	39% 5% 10% 27% 17% 3	5464
April	1st to 10th	Day	32% 4 10% 25% 21% 7%	2200
	11th to 20th	Day	38% 4 9% 21% 21% 8%	2369
	21st to end	Day	39% 5% 9% 25% 20% 3	2600
May	1st to 10th	Day	44% 6% 11% 19% 16% 3	5900
	11th to 20th	Day	31% 6% 10% 22% 23% 7%	5866
	21st to end	Day	42% 7% 10% 19% 16% 6%	6447
June	1st to 10th	Day	30% 7% 18% 27% 15% 3	2600
	11th to 20th	Day	27% 5% 14% 29% 22% 4	2600
	21st to end	Day	23% 5% 15% 28% 24% 6%	2600
July	1st to 10th	Day	36% 8% 14% 22% 17% 3	5836
	11th to 20th	Day	24% 6% 12% 30% 24% 3	5831
	21st to end	Day	18% 6% 17% 37% 22% 1	6240
August	1st to 10th	Day	24% 5% 11% 27% 24% 9%	4220
	11th to 20th	Day	25% 5% 15% 32% 19% 4	4210
	21st to end	Day	22% 5% 12% 41% 16% 4	4352
September	1st to 10th	Day	28% 4 7% 24% 26% 11%	2123
	11th to 20th	Day	34% 5% 8% 22% 25% 6%	2090
	21st to end	Day	27% 3 6% 25% 31% 7%	2090
October	1st to 10th	Day	16% 2 7% 14% 46% 15%	3419
	11th to 20th	Day	16% 3 6% 24% 35% 16%	3140
	21st to end	Day	24% 3 6% 29% 30% 9%	3428
November	1st to 10th	Day	26% 3 7% 25% 29% 10%	1873
	11th to 20th	Day	23% 2 7% 28% 28% 11%	1800
	21st to end	Day	28% 3 6% 27% 27% 10%	1800
December	1st to 10th	Day	27% 4 8% 37% 23% 3	2940
	11th to 20th	Day	28% 3 5% 24% 32% 9%	3389
	21st to end	Day	42% 4 6% 24% 19% 4	4488
January	1st to 10th	Night	37% 4 7% 27% 20% 4	5888
	11th to 20th	Night	20% 4 11% 21% 34% 11%	5900
	21st to end	Night	36% 3 6% 17% 31% 7%	6490
February	1st to 10th	Night	37% 3 7% 22% 24% 7%	2530
	11th to 20th	Night	34% 3 8% 25% 23% 7%	2338
	21st to end	Night	35% 3 4 18% 26% 13%	1980
March	1st to 10th	Night	30% 3 5% 17% 26% 19%	5013
	11th to 20th	Night	22% 3 6% 23% 22% 24%	4980
	21st to end	Night	35% 5% 10% 26% 21% 3	5467
April	1st to 10th	Night	29% 4 10% 22% 23% 13%	2200
	11th to 20th	Night	31% 5% 9% 24% 20% 11%	1976
	21st to end	Night	34% 4 11% 25% 22% 4	1800
May	1st to 10th	Night	40% 5% 11% 20% 19% 4	4080
	11th to 20th	Night	28% 6% 10% 24% 21% 10%	4054
	21st to end	Night	31% 6% 14% 21% 19% 9%	4452
June	1st to 10th	Night	22% 6% 20% 29% 19% 4	1800
	11th to 20th	Night	24% 5% 14% 29% 22% 6%	1800
	21st to end	Night	16% 5% 14% 30% 27% 8%	1800
July	1st to 10th	Night	29% 8% 18% 27% 15% 3	4035
	11th to 20th	Night	17% 6% 12% 35% 26% 4	4026
	21st to end	Night	16% 4 15% 36% 27% 2	4320
August	1st to 10th	Night	16% 4 13% 28% 32% 8%	2916
	11th to 20th	Night	23% 5% 12% 33% 23% 4	2915
	21st to end	Night	16% 6% 15% 38% 21% 5%	3546
September	1st to 10th	Night	27% 3 8% 24% 26% 13%	2123
	11th to 20th	Night	32% 4 8% 20% 27% 9%	2090
	21st to end	Night	23% 4 6% 26% 32% 9%	2090
October	1st to 10th	Night	16% 3 7% 14% 38% 22%	3507
	11th to 20th	Night	16% 2 5% 19% 39% 18%	3779
	21st to end	Night	20% 3 6% 28% 33% 10%	4120
November	1st to 10th	Night	23% 3 8% 23% 31% 13%	2423
	11th to 20th	Night	25% 3 6% 23% 30% 12%	2600
	21st to end	Night	29% 3 6% 22% 29% 11%	2600
December	1st to 10th	Night	23% 3 7% 37% 26% 4	4250
	11th to 20th	Night	30% 3 5% 22% 31% 9%	4817
	21st to end	Night	37% 4 5% 26% 22% 6%	6490

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	20% 26% 37% 12% 6%	300
	11th to 20th	Day	23% 25% 39% 11% 1	300
	21st to end	Day	16% 28% 38% 14% 3	330
February	1st to 10th	Day	24% 27% 35% 11% 3	300
	11th to 20th	Day	21% 32% 38% 8% 1	300
	21st to end	Day	27% 29% 35% 7% 2	249
March	1st to 10th	Day	21% 28% 38% 11% 1	300
	11th to 20th	Day	31% 24% 34% 9% 1	300
	21st to end	Day	25% 25% 38% 9% 2	330
April	1st to 10th	Day	27% 24% 32% 15% 1	300
	11th to 20th	Day	24% 27% 36% 11% 2	487
	21st to end	Day	22% 23% 33% 16% 6%	700
May	1st to 10th	Day	17% 19% 41% 19% 3 1	703
	11th to 20th	Day	17% 15% 35% 22% 10% 1	725
	21st to end	Day	15% 11% 35% 25% 12% 2	789
June	1st to 10th	Day	8% 5% 29% 40% 14% 2	730
	11th to 20th	Day	6% 5% 40% 34% 12% 2	730
	21st to end	Day	4 4 35% 40% 15% 2	730
July	1st to 10th	Day	7% 3 20% 40% 25% 4	721
	11th to 20th	Day	3 2 22% 50% 19% 3	718
	21st to end	Day	7% 2 16% 46% 25% 5%	794
August	1st to 10th	Day	6% 3 23% 42% 22% 3	726
	11th to 20th	Day	8% 3 21% 43% 22% 3	715
	21st to end	Day	8% 1 17% 42% 27% 4	611
September	1st to 10th	Day	9% 4 17% 43% 24% 4	309
	11th to 20th	Day	7% 5% 22% 42% 20% 4	300
	21st to end	Day	12% 6% 28% 36% 15% 3	300
October	1st to 10th	Day	9% 8% 38% 28% 12% 4	300
	11th to 20th	Day	11% 15% 45% 23% 5%	300
	21st to end	Day	22% 19% 34% 18% 6% 1	330
November	1st to 10th	Day	17% 17% 42% 20% 3 2	300
	11th to 20th	Day	18% 21% 35% 20% 5% 1	300
	21st to end	Day	22% 25% 34% 14% 4	300
December	1st to 10th	Day	16% 27% 35% 16% 5%	300
	11th to 20th	Day	19% 26% 34% 15% 5%	300
	21st to end	Day	27% 22% 36% 13% 2	330
January	1st to 10th	Night	12% 18% 41% 23% 5% 1	1000
	11th to 20th	Night	14% 17% 41% 24% 3	1000
	21st to end	Night	12% 20% 37% 26% 4	1100
February	1st to 10th	Night	19% 19% 38% 21% 3	930
	11th to 20th	Night	19% 20% 39% 18% 3	784
	21st to end	Night	19% 20% 37% 21% 2	660
March	1st to 10th	Night	13% 20% 39% 24% 3	646
	11th to 20th	Night	20% 19% 38% 21% 2	600
	21st to end	Night	19% 22% 37% 18% 4	660
April	1st to 10th	Night	15% 24% 38% 18% 4	600
	11th to 20th	Night	16% 20% 45% 16% 4	593
	21st to end	Night	18% 17% 38% 21% 6% 1	600
May	1st to 10th	Night	13% 15% 45% 21% 6%	600
	11th to 20th	Night	15% 12% 37% 23% 13% 1	591
	21st to end	Night	10% 9% 40% 28% 11% 1	650
June	1st to 10th	Night	9% 5% 34% 37% 13% 3	600
	11th to 20th	Night	7% 4 46% 35% 8% 1	600
	21st to end	Night	3 2 42% 38% 13% 1	600
July	1st to 10th	Night	5% 2 27% 43% 20% 2	585
	11th to 20th	Night	3 1 31% 47% 16% 2	582
	21st to end	Night	4 2 21% 53% 19% 2	657
August	1st to 10th	Night	2 3 29% 43% 20% 3	597
	11th to 20th	Night	6% 2 27% 43% 19% 2	594
	21st to end	Night	3 1 23% 44% 27% 2	660
September	1st to 10th	Night	8% 3 26% 40% 21% 2	579
	11th to 20th	Night	12% 3 30% 34% 19% 3	570
	21st to end	Night	9% 4 34% 32% 16% 3	570
October	1st to 10th	Night	9% 7% 33% 33% 16% 2	584
	11th to 20th	Night	11% 13% 40% 27% 8%	760
	21st to end	Night	16% 14% 36% 23% 10% 1	836
November	1st to 10th	Night	11% 13% 42% 24% 10% 1	863
	11th to 20th	Night	10% 20% 35% 27% 8%	1000
	21st to end	Night	16% 18% 33% 26% 7%	1000
December	1st to 10th	Night	13% 17% 37% 28% 5%	1000
	11th to 20th	Night	17% 18% 38% 21% 6%	1000
	21st to end	Night	18% 18% 35% 25% 4	1100

Page generated at 2025-09-01 00:51:09. Version ac07

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