TAS-D Atoka
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the TAS-D Atoka clear sky chart from 2005-11-06 to 2024-01-15.

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	12% 5% 2 4 4 3 4 4 5% 7% 49%	74971
	Night	11% 5% 2 4 4 2 3 4 4 7% 55%	74846
Transparency	Day	35% 6% 11% 23% 21% 6%	74696
	Night	30% 5% 10% 23% 24% 9%	74641
Seeing	Day	13% 8% 23% 28% 21% 6%	14141
	Night	13% 8% 28% 33% 16% 1	24132

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	14% 7% 3 4 3 2 2 3 4 6% 52%	1707
	11th to 20th	Day	14% 6% 2 4 4 2 4 3 3 5% 53%	1661
	21st to end	Day	15% 7% 2 4 4 2 3 3 4 5% 51%	1782
February	1st to 10th	Day	18% 7% 3 6% 4 2 4 4 3 4 46%	1637
	11th to 20th	Day	17% 7% 3 5% 4 2 4 3 4 6% 45%	1749
	21st to end	Day	23% 7% 4 5% 3 2 2 4 4 4 44%	1529
March	1st to 10th	Day	16% 6% 3 4 4 3 4 4 4 6% 46%	1980
	11th to 20th	Day	20% 7% 2 5% 5% 2 3 3 3 4 44%	1980
	21st to end	Day	17% 8% 3 5% 5% 3 4 4 4 5% 44%	2178
April	1st to 10th	Day	13% 6% 3 5% 4 2 4 4 4 6% 48%	1980
	11th to 20th	Day	15% 4 2 5% 5% 2 5% 4 5% 7% 46%	2106
	21st to end	Day	15% 6% 3 6% 5% 2 5% 4 5% 6% 43%	2263
May	1st to 10th	Day	15% 6% 3 5% 5% 3 4 4 5% 7% 45%	2340
	11th to 20th	Day	14% 7% 2 5% 5% 3 5% 5% 5% 7% 43%	2302
	21st to end	Day	11% 6% 3 5% 6% 5% 6% 5% 6% 8% 39%	2531
June	1st to 10th	Day	7% 6% 2 5% 5% 3 5% 5% 6% 9% 47%	2340
	11th to 20th	Day	8% 4 3 4 4 4 5% 5% 6% 10% 47%	2340
	21st to end	Day	4 3 1 3 4 3 5% 6% 6% 9% 55%	2340
July	1st to 10th	Day	6% 4 3 5% 6% 4 5% 7% 8% 10% 42%	2340
	11th to 20th	Day	3 2 1 2 4 3 5% 6% 6% 9% 58%	2340
	21st to end	Day	5% 2 2 4 5% 4 6% 5% 7% 10% 50%	2546
August	1st to 10th	Day	3 3 1 3 4 3 5% 6% 6% 9% 55%	2328
	11th to 20th	Day	8% 4 2 4 5% 3 5% 5% 7% 8% 50%	2301
	21st to end	Day	3 2 2 4 5% 4 5% 6% 8% 11% 50%	2410
September	1st to 10th	Day	10% 4 2 3 4 3 4 4 5% 7% 54%	1980
	11th to 20th	Day	10% 4 3 4 5% 3 6% 5% 5% 7% 48%	1980
	21st to end	Day	7% 3 1 4 4 2 4 4 4 7% 59%	1980
October	1st to 10th	Day	7% 4 1 4 5% 2 4 5% 4 6% 57%	1885
	11th to 20th	Day	12% 4 2 3 3 2 2 2 3 4 62%	1800
	21st to end	Day	18% 5% 1 4 3 2 2 3 3 4 54%	1980
November	1st to 10th	Day	12% 5% 2 5% 3 2 4 3 4 6% 54%	1858
	11th to 20th	Day	10% 4 3 4 3 2 3 3 3 5% 61%	1782
	21st to end	Day	18% 5% 2 3 3 1 3 3 3 6% 53%	1710
December	1st to 10th	Day	14% 6% 3 4 3 2 2 3 5% 6% 52%	1710
	11th to 20th	Day	17% 8% 3 4 4 3 4 5% 3 5% 46%	2161
	21st to end	Day	21% 7% 2 3 4 2 3 4 4 6% 45%	3135
January	1st to 10th	Night	12% 5% 1 4 4 2 3 4 4 5% 56%	2458
	11th to 20th	Night	13% 6% 3 4 4 2 2 3 3 6% 55%	2405
	21st to end	Night	13% 5% 2 3 4 2 3 3 4 5% 56%	2574
February	1st to 10th	Night	15% 7% 2 4 4 2 3 4 5% 4 50%	2339
	11th to 20th	Night	15% 8% 3 5% 3 2 4 3 4 6% 48%	2098
	21st to end	Night	17% 6% 2 4 3 2 3 2 4 4 50%	1726
March	1st to 10th	Night	15% 6% 2 5% 4 3 3 4 5% 6% 48%	1980
	11th to 20th	Night	15% 7% 3 5% 4 2 3 3 4 6% 49%	1980
	21st to end	Night	14% 5% 3 4 4 2 4 4 5% 7% 49%	2178
April	1st to 10th	Night	11% 5% 2 5% 4 3 4 3 4 6% 53%	1980
	11th to 20th	Night	13% 4 2 4 4 3 3 3 4 7% 52%	1802
	21st to end	Night	15% 4 2 3 4 2 4 3 5% 7% 50%	1692
May	1st to 10th	Night	11% 5% 2 4 5% 2 5% 5% 5% 8% 49%	1620
	11th to 20th	Night	12% 5% 2 3 4 3 4 4 5% 8% 50%	1593
	21st to end	Night	7% 4 2 5% 4 2 4 6% 6% 9% 49%	1745
June	1st to 10th	Night	4 4 1 4 4 2 4 5% 6% 8% 59%	1620
	11th to 20th	Night	5% 3 1 3 3 2 4 4 6% 10% 60%	1620
	21st to end	Night	3 2 1 2 3 2 4 4 5% 8% 65%	1620
July	1st to 10th	Night	5% 3 2 3 5% 3 4 6% 6% 11% 53%	1620
	11th to 20th	Night	3 1 1 2 2 2 2 4 5% 11% 67%	1620
	21st to end	Night	2 1 1 3 3 2 4 5% 8% 10% 60%	1772
August	1st to 10th	Night	2 2 1 2 3 3 4 6% 6% 8% 63%	1611
	11th to 20th	Night	4 3 1 3 4 2 4 5% 6% 11% 57%	1600
	21st to end	Night	3 3 2 3 4 3 4 5% 5% 9% 58%	1939
September	1st to 10th	Night	7% 4 2 3 3 2 3 4 5% 7% 61%	1980
	11th to 20th	Night	9% 4 2 5% 4 3 4 4 5% 6% 52%	1980
	21st to end	Night	7% 3 2 3 3 2 3 3 4 6% 64%	1980
October	1st to 10th	Night	8% 4 2 4 4 3 3 3 4 5% 61%	2056
	11th to 20th	Night	13% 4 1 3 3 2 2 3 4 5% 61%	2160
	21st to end	Night	17% 4 2 3 3 2 2 2 3 4 58%	2376
November	1st to 10th	Night	11% 4 1 4 3 2 3 3 4 6% 59%	2220
	11th to 20th	Night	9% 4 2 4 3 2 4 4 3 6% 60%	2394
	21st to end	Night	17% 5% 2 3 3 1 3 3 4 6% 53%	2470
December	1st to 10th	Night	14% 5% 2 4 3 2 3 3 5% 6% 54%	2470
	11th to 20th	Night	14% 6% 3 5% 5% 2 3 3 4 5% 50%	3036
	21st to end	Night	18% 8% 2 4 3 2 2 3 3 4 51%	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	35% 3 9% 22% 25% 6%	1708
	11th to 20th	Day	35% 4 7% 24% 26% 5%	1661
	21st to end	Day	36% 4 6% 22% 25% 8%	1782
February	1st to 10th	Day	44% 4 9% 18% 21% 5%	1637
	11th to 20th	Day	43% 4 8% 22% 18% 6%	1759
	21st to end	Day	45% 3 5% 13% 24% 9%	1529
March	1st to 10th	Day	40% 5% 8% 17% 19% 12%	1980
	11th to 20th	Day	45% 4 7% 21% 18% 6%	1980
	21st to end	Day	44% 5% 8% 21% 19% 4	2178
April	1st to 10th	Day	39% 4 10% 21% 18% 8%	1980
	11th to 20th	Day	38% 6% 11% 21% 18% 6%	2106
	21st to end	Day	42% 5% 9% 20% 20% 4	2263
May	1st to 10th	Day	40% 6% 11% 21% 18% 4	2340
	11th to 20th	Day	40% 8% 12% 23% 16% 1	2306
	21st to end	Day	43% 8% 13% 20% 15% 1	2531
June	1st to 10th	Day	33% 7% 15% 27% 15% 2	2340
	11th to 20th	Day	32% 8% 13% 27% 18% 2	2340
	21st to end	Day	25% 8% 13% 27% 24% 3	2340
July	1st to 10th	Day	34% 11% 19% 23% 13% 1	2276
	11th to 20th	Day	20% 7% 16% 31% 22% 4	2271
	21st to end	Day	25% 9% 18% 33% 16%	2405
August	1st to 10th	Day	21% 9% 16% 29% 23% 2	2314
	11th to 20th	Day	30% 8% 14% 26% 20% 3	2301
	21st to end	Day	26% 9% 17% 27% 16% 4	2410
September	1st to 10th	Day	29% 5% 12% 24% 20% 10%	1980
	11th to 20th	Day	34% 8% 11% 20% 20% 7%	1980
	21st to end	Day	26% 5% 9% 21% 29% 9%	1980
October	1st to 10th	Day	28% 5% 12% 20% 22% 13%	1885
	11th to 20th	Day	29% 3 6% 16% 30% 15%	1800
	21st to end	Day	36% 3 7% 18% 25% 11%	1980
November	1st to 10th	Day	33% 3 9% 23% 25% 7%	1858
	11th to 20th	Day	27% 3 9% 23% 29% 10%	1782
	21st to end	Day	35% 3 6% 19% 27% 9%	1710
December	1st to 10th	Day	34% 4 9% 28% 21% 5%	1710
	11th to 20th	Day	42% 4 5% 19% 23% 7%	2159
	21st to end	Day	41% 3 7% 22% 23% 5%	3135
January	1st to 10th	Night	31% 4 8% 20% 30% 7%	2458
	11th to 20th	Night	33% 3 8% 23% 25% 8%	2405
	21st to end	Night	32% 4 5% 19% 28% 12%	2574
February	1st to 10th	Night	39% 4 9% 20% 22% 7%	2339
	11th to 20th	Night	39% 4 7% 21% 22% 7%	2098
	21st to end	Night	39% 4 7% 17% 21% 13%	1726
March	1st to 10th	Night	39% 3 7% 18% 18% 15%	1980
	11th to 20th	Night	39% 4 8% 20% 20% 9%	1980
	21st to end	Night	36% 5% 11% 21% 22% 5%	2178
April	1st to 10th	Night	34% 4 10% 20% 21% 12%	1980
	11th to 20th	Night	34% 5% 9% 21% 19% 12%	1802
	21st to end	Night	34% 5% 10% 24% 23% 4	1692
May	1st to 10th	Night	35% 6% 10% 21% 19% 9%	1620
	11th to 20th	Night	34% 6% 14% 26% 17% 2	1594
	21st to end	Night	30% 8% 16% 26% 16% 3	1746
June	1st to 10th	Night	22% 7% 15% 31% 21% 3	1620
	11th to 20th	Night	20% 6% 13% 33% 23% 5%	1620
	21st to end	Night	17% 6% 13% 28% 30% 6%	1620
July	1st to 10th	Night	24% 8% 17% 29% 19% 3	1575
	11th to 20th	Night	12% 5% 16% 36% 27% 5%	1566
	21st to end	Night	18% 7% 15% 34% 26% 1	1673
August	1st to 10th	Night	16% 6% 13% 34% 25% 5%	1601
	11th to 20th	Night	22% 5% 13% 29% 25% 5%	1600
	21st to end	Night	22% 7% 16% 30% 20% 5%	1939
September	1st to 10th	Night	23% 6% 11% 23% 27% 9%	1980
	11th to 20th	Night	31% 6% 10% 20% 21% 11%	1980
	21st to end	Night	21% 4 8% 25% 29% 13%	1980
October	1st to 10th	Night	25% 5% 10% 22% 23% 16%	2056
	11th to 20th	Night	27% 3 7% 14% 29% 19%	2160
	21st to end	Night	32% 3 5% 20% 26% 14%	2376
November	1st to 10th	Night	29% 3 8% 23% 26% 12%	2220
	11th to 20th	Night	27% 4 7% 22% 27% 12%	2394
	21st to end	Night	34% 3 7% 19% 28% 8%	2470
December	1st to 10th	Night	32% 4 10% 23% 22% 9%	2470
	11th to 20th	Night	38% 3 6% 16% 28% 9%	3037
	21st to end	Night	38% 3 7% 22% 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	21% 17% 33% 24% 5%	270
	11th to 20th	Day	20% 20% 35% 19% 5% 1	254
	21st to end	Day	19% 20% 33% 18% 9% 1	264
February	1st to 10th	Day	25% 15% 35% 20% 4	240
	11th to 20th	Day	25% 19% 38% 16% 1	240
	21st to end	Day	33% 16% 37% 11% 3	198
March	1st to 10th	Day	22% 19% 35% 18% 7%	240
	11th to 20th	Day	27% 23% 29% 15% 5% 3	240
	21st to end	Day	21% 17% 42% 16% 5%	264
April	1st to 10th	Day	18% 20% 34% 22% 5%	240
	11th to 20th	Day	21% 16% 33% 25% 5%	384
	21st to end	Day	17% 17% 35% 24% 5% 2	523
May	1st to 10th	Day	15% 11% 37% 28% 8%	603
	11th to 20th	Day	15% 8% 32% 28% 14% 3	625
	21st to end	Day	12% 8% 31% 28% 16% 5%	679
June	1st to 10th	Day	8% 3 18% 37% 26% 9%	630
	11th to 20th	Day	8% 3 20% 38% 26% 6%	630
	21st to end	Day	4 2 17% 36% 30% 11%	630
July	1st to 10th	Day	5% 1 11% 34% 34% 15%	621
	11th to 20th	Day	2 1 7% 33% 43% 12%	618
	21st to end	Day	3 1 6% 33% 40% 17%	684
August	1st to 10th	Day	4 1 10% 33% 42% 10%	626
	11th to 20th	Day	8% 3 10% 36% 36% 7%	615
	21st to end	Day	5% 1 5% 30% 42% 17%	529
September	1st to 10th	Day	6% 1 7% 28% 37% 21%	270
	11th to 20th	Day	6% 3 7% 32% 36% 16%	270
	21st to end	Day	13% 4 13% 34% 26% 11%	270
October	1st to 10th	Day	4 4 27% 30% 27% 9%	270
	11th to 20th	Day	16% 10% 27% 28% 18% 1	270
	21st to end	Day	28% 11% 25% 20% 15% 1	297
November	1st to 10th	Day	16% 9% 37% 23% 12% 2	270
	11th to 20th	Day	14% 14% 34% 24% 10% 3	270
	21st to end	Day	24% 13% 30% 22% 9% 1	270
December	1st to 10th	Day	15% 15% 35% 25% 9%	270
	11th to 20th	Day	26% 10% 36% 23% 6%	270
	21st to end	Day	21% 19% 33% 22% 4	297
January	1st to 10th	Night	15% 15% 34% 29% 8%	950
	11th to 20th	Night	18% 16% 33% 27% 6%	925
	21st to end	Night	15% 11% 37% 30% 7%	990
February	1st to 10th	Night	18% 17% 33% 27% 4	899
	11th to 20th	Night	21% 13% 38% 25% 3	704
	21st to end	Night	23% 15% 40% 19% 4	542
March	1st to 10th	Night	18% 13% 36% 28% 5%	540
	11th to 20th	Night	19% 12% 37% 27% 5%	540
	21st to end	Night	18% 12% 39% 26% 5% 1	594
April	1st to 10th	Night	13% 15% 40% 28% 4	540
	11th to 20th	Night	16% 13% 37% 27% 7%	533
	21st to end	Night	16% 11% 37% 27% 8% 1	540
May	1st to 10th	Night	12% 7% 38% 35% 9%	540
	11th to 20th	Night	13% 5% 33% 33% 15% 1	531
	21st to end	Night	7% 3 32% 37% 19% 2	584
June	1st to 10th	Night	5% 3 17% 41% 29% 4	540
	11th to 20th	Night	5% 1 20% 54% 18% 1	540
	21st to end	Night	2 1 14% 49% 30% 5%	540
July	1st to 10th	Night	5% 1 8% 41% 40% 5%	525
	11th to 20th	Night	3 1 9% 44% 40% 4	522
	21st to end	Night	2 1 6% 45% 41% 5%	591
August	1st to 10th	Night	2 7% 50% 39% 3	537
	11th to 20th	Night	6% 9% 42% 38% 4	534
	21st to end	Night	4 1 5% 43% 42% 5%	594
September	1st to 10th	Night	7% 1 10% 38% 39% 4	540
	11th to 20th	Night	10% 2 13% 36% 35% 3	540
	21st to end	Night	7% 1 18% 38% 33% 2	540
October	1st to 10th	Night	10% 3 20% 41% 23% 3	616
	11th to 20th	Night	15% 6% 29% 34% 15% 1	720
	21st to end	Night	19% 9% 29% 30% 13% 1	792
November	1st to 10th	Night	13% 6% 33% 36% 11% 1	740
	11th to 20th	Night	12% 12% 31% 34% 11%	874
	21st to end	Night	19% 11% 32% 27% 10%	950
December	1st to 10th	Night	17% 12% 33% 31% 7%	950
	11th to 20th	Night	21% 9% 35% 29% 6%	950
	21st to end	Night	20% 12% 36% 27% 6%	1045

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