Choteau(OK)
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Choteau(OK) 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% 6% 3 5% 5% 3 4 4 5% 7% 47%	74978
	Night	11% 5% 2 4 4 2 4 4 5% 7% 52%	74823
Transparency	Day	37% 4 11% 25% 18% 4	74702
	Night	33% 4 10% 25% 22% 6%	74619
Seeing	Day	15% 11% 28% 27% 16% 4	14307
	Night	14% 12% 31% 30% 12% 1	24282

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% 10% 3 4 4 2 3 3 4 6% 50%	1707
	11th to 20th	Day	13% 8% 2 6% 4 3 3 3 3 5% 49%	1656
	21st to end	Day	15% 8% 3 5% 3 2 3 3 3 6% 49%	1782
February	1st to 10th	Day	16% 10% 4 5% 5% 3 3 3 4 4 43%	1620
	11th to 20th	Day	15% 7% 3 5% 5% 2 3 5% 4 6% 44%	1659
	21st to end	Day	17% 8% 3 5% 4 2 5% 3 3 6% 43%	1548
March	1st to 10th	Day	14% 8% 3 5% 4 2 4 3 5% 5% 47%	1980
	11th to 20th	Day	19% 7% 3 5% 4 2 3 4 3 7% 42%	1980
	21st to end	Day	19% 9% 4 6% 5% 3 4 4 4 6% 35%	2178
April	1st to 10th	Day	11% 7% 3 5% 5% 3 5% 4 6% 7% 44%	2020
	11th to 20th	Day	15% 6% 3 5% 5% 3 4 5% 5% 7% 42%	2134
	21st to end	Day	18% 8% 4 6% 5% 2 3 3 4 6% 41%	2254
May	1st to 10th	Day	17% 7% 3 6% 5% 3 4 4 4 6% 41%	2340
	11th to 20th	Day	12% 6% 2 6% 7% 3 5% 5% 6% 8% 40%	2302
	21st to end	Day	11% 6% 3 7% 7% 3 5% 7% 7% 9% 35%	2531
June	1st to 10th	Day	7% 4 2 5% 5% 3 6% 6% 7% 8% 48%	2340
	11th to 20th	Day	8% 3 2 5% 4 3 6% 5% 6% 9% 49%	2340
	21st to end	Day	5% 2 1 3 4 2 5% 5% 6% 9% 58%	2340
July	1st to 10th	Day	8% 4 2 4 5% 4 6% 7% 8% 10% 42%	2340
	11th to 20th	Day	3 3 1 3 4 3 5% 5% 6% 11% 56%	2340
	21st to end	Day	7% 4 2 4 5% 4 5% 5% 7% 11% 46%	2546
August	1st to 10th	Day	5% 3 2 4 5% 3 4 6% 8% 10% 49%	2328
	11th to 20th	Day	8% 4 2 4 5% 3 5% 5% 7% 9% 47%	2301
	21st to end	Day	5% 4 2 4 4 3 6% 4 6% 9% 54%	2415
September	1st to 10th	Day	10% 5% 2 4 4 2 4 4 5% 7% 53%	2084
	11th to 20th	Day	11% 4 2 5% 5% 3 4 5% 6% 7% 47%	1980
	21st to end	Day	7% 4 2 4 5% 3 4 4 5% 7% 56%	1980
October	1st to 10th	Day	11% 4 2 3 3 3 4 3 5% 7% 56%	1832
	11th to 20th	Day	12% 4 2 3 3 2 3 3 4 4 61%	1800
	21st to end	Day	18% 5% 2 4 3 2 2 3 3 5% 52%	1980
November	1st to 10th	Day	10% 4 2 4 3 3 3 3 4 6% 59%	1858
	11th to 20th	Day	12% 5% 2 4 3 3 3 4 3 5% 56%	1767
	21st to end	Day	15% 8% 3 3 2 1 3 3 4 8% 50%	1710
December	1st to 10th	Day	14% 7% 2 5% 4 3 4 4 5% 5% 47%	1710
	11th to 20th	Day	14% 8% 3 6% 6% 2 4 3 4 6% 44%	2161
	21st to end	Day	18% 15% 5% 6% 5% 3 3 4 4 5% 31%	3135
January	1st to 10th	Night	12% 6% 2 4 4 2 3 4 5% 7% 51%	2458
	11th to 20th	Night	13% 6% 2 5% 3 2 3 3 5% 6% 52%	2393
	21st to end	Night	12% 6% 2 4 3 2 3 3 4 6% 55%	2574
February	1st to 10th	Night	15% 8% 3 6% 3 3 3 3 4 6% 45%	2340
	11th to 20th	Night	15% 7% 3 6% 3 2 2 3 4 5% 49%	2202
	21st to end	Night	16% 7% 3 4 4 3 4 3 3 5% 48%	1706
March	1st to 10th	Night	12% 6% 3 5% 4 2 5% 4 4 6% 48%	1980
	11th to 20th	Night	18% 6% 2 4 4 2 4 3 4 5% 48%	1980
	21st to end	Night	15% 6% 3 6% 4 2 3 4 5% 6% 46%	2178
April	1st to 10th	Night	11% 6% 3 3 4 2 3 4 5% 6% 53%	1940
	11th to 20th	Night	15% 5% 2 4 4 3 2 3 5% 6% 50%	1775
	21st to end	Night	17% 5% 3 6% 4 2 3 3 4 5% 48%	1702
May	1st to 10th	Night	12% 5% 3 5% 4 3 4 5% 5% 8% 46%	1620
	11th to 20th	Night	13% 4 1 6% 4 2 4 5% 6% 8% 48%	1593
	21st to end	Night	9% 5% 3 5% 5% 3 4 6% 7% 11% 41%	1745
June	1st to 10th	Night	6% 3 2 4 5% 3 4 5% 6% 9% 55%	1620
	11th to 20th	Night	4 2 2 4 4 3 4 5% 6% 11% 56%	1620
	21st to end	Night	4 1 1 3 3 2 4 4 5% 8% 65%	1620
July	1st to 10th	Night	6% 3 1 4 4 3 4 5% 7% 11% 51%	1620
	11th to 20th	Night	3 2 1 3 3 2 4 4 6% 10% 61%	1620
	21st to end	Night	4 3 1 4 4 3 4 5% 5% 11% 55%	1772
August	1st to 10th	Night	4 2 1 3 4 3 4 5% 9% 12% 54%	1611
	11th to 20th	Night	6% 4 2 4 4 2 5% 6% 6% 8% 53%	1600
	21st to end	Night	3 3 2 3 4 3 5% 4 6% 10% 58%	1939
September	1st to 10th	Night	8% 4 2 4 3 2 4 4 4 7% 59%	1872
	11th to 20th	Night	9% 4 2 5% 4 3 4 4 5% 8% 52%	1980
	21st to end	Night	8% 3 1 3 3 2 3 5% 4 6% 61%	1980
October	1st to 10th	Night	7% 3 1 4 4 3 3 4 4 7% 61%	2110
	11th to 20th	Night	12% 4 1 3 3 2 3 3 4 5% 59%	2160
	21st to end	Night	16% 5% 1 3 3 2 3 3 3 5% 55%	2376
November	1st to 10th	Night	11% 4 1 3 3 1 2 3 2 5% 64%	2220
	11th to 20th	Night	10% 5% 2 4 4 1 3 4 3 5% 59%	2409
	21st to end	Night	14% 6% 2 5% 3 1 2 3 4 5% 54%	2470
December	1st to 10th	Night	13% 6% 2 5% 3 3 4 3 4 6% 51%	2470
	11th to 20th	Night	13% 7% 3 6% 4 3 4 3 4 6% 47%	3036
	21st to end	Night	17% 10% 4 6% 5% 2 4 3 4 5% 40%	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% 3 9% 27% 21% 3	1708
	11th to 20th	Day	39% 2 9% 28% 20% 2	1656
	21st to end	Day	39% 3 10% 29% 17% 3	1782
February	1st to 10th	Day	46% 3 11% 22% 15% 3	1620
	11th to 20th	Day	43% 3 9% 25% 16% 3	1668
	21st to end	Day	45% 3 7% 22% 16% 8%	1548
March	1st to 10th	Day	40% 3 7% 22% 19% 9%	1980
	11th to 20th	Day	45% 4 9% 22% 16% 4	1980
	21st to end	Day	51% 4 9% 21% 12% 2	2178
April	1st to 10th	Day	39% 5% 11% 23% 17% 5%	2020
	11th to 20th	Day	42% 4 12% 22% 15% 5%	2134
	21st to end	Day	46% 4 9% 24% 16% 1	2254
May	1st to 10th	Day	45% 4 10% 22% 18% 1	2340
	11th to 20th	Day	41% 5% 16% 24% 13% 1	2306
	21st to end	Day	43% 7% 16% 23% 11% 1	2531
June	1st to 10th	Day	33% 7% 15% 27% 16% 2	2340
	11th to 20th	Day	32% 6% 14% 31% 16% 2	2340
	21st to end	Day	23% 5% 15% 31% 20% 5%	2340
July	1st to 10th	Day	33% 7% 16% 28% 15% 1	2276
	11th to 20th	Day	23% 6% 14% 33% 22% 3	2271
	21st to end	Day	30% 5% 16% 31% 16% 1	2405
August	1st to 10th	Day	28% 6% 16% 29% 18% 3	2314
	11th to 20th	Day	33% 5% 14% 25% 20% 3	2301
	21st to end	Day	27% 5% 14% 29% 19% 6%	2415
September	1st to 10th	Day	30% 5% 10% 25% 22% 8%	2084
	11th to 20th	Day	34% 5% 12% 22% 22% 5%	1980
	21st to end	Day	28% 5% 8% 24% 28% 6%	1980
October	1st to 10th	Day	29% 4 12% 24% 26% 6%	1832
	11th to 20th	Day	28% 3 5% 25% 31% 8%	1800
	21st to end	Day	37% 2 9% 26% 18% 8%	1980
November	1st to 10th	Day	29% 3 9% 27% 26% 7%	1858
	11th to 20th	Day	33% 2 7% 27% 24% 7%	1767
	21st to end	Day	36% 3 8% 24% 24% 4	1710
December	1st to 10th	Day	39% 3 9% 28% 19% 2	1710
	11th to 20th	Day	42% 3 6% 23% 23% 3	2159
	21st to end	Day	55% 4 9% 20% 10% 2	3135
January	1st to 10th	Night	34% 3 10% 26% 23% 4	2458
	11th to 20th	Night	35% 3 10% 27% 21% 3	2393
	21st to end	Night	33% 2 8% 29% 22% 5%	2574
February	1st to 10th	Night	42% 3 11% 23% 18% 4	2340
	11th to 20th	Night	39% 2 8% 27% 19% 4	2203
	21st to end	Night	41% 3 6% 19% 23% 8%	1706
March	1st to 10th	Night	38% 4 8% 18% 20% 11%	1980
	11th to 20th	Night	40% 3 11% 22% 19% 5%	1980
	21st to end	Night	39% 4 10% 27% 16% 3	2178
April	1st to 10th	Night	32% 4 9% 24% 21% 8%	1940
	11th to 20th	Night	36% 4 9% 24% 19% 7%	1775
	21st to end	Night	40% 4 9% 24% 22% 2	1702
May	1st to 10th	Night	37% 5% 12% 22% 20% 4	1620
	11th to 20th	Night	34% 5% 14% 26% 19% 2	1594
	21st to end	Night	36% 6% 18% 24% 14% 1	1746
June	1st to 10th	Night	26% 4 17% 30% 19% 3	1620
	11th to 20th	Night	22% 5% 15% 33% 21% 4	1620
	21st to end	Night	18% 5% 13% 32% 26% 7%	1620
July	1st to 10th	Night	25% 6% 15% 31% 20% 3	1575
	11th to 20th	Night	19% 5% 13% 31% 27% 5%	1566
	21st to end	Night	23% 4 13% 36% 21% 2	1673
August	1st to 10th	Night	21% 6% 16% 35% 21% 2	1601
	11th to 20th	Night	28% 6% 11% 22% 28% 6%	1600
	21st to end	Night	23% 5% 14% 29% 22% 8%	1939
September	1st to 10th	Night	26% 5% 9% 27% 25% 9%	1872
	11th to 20th	Night	31% 4 10% 23% 24% 8%	1980
	21st to end	Night	25% 4 7% 26% 31% 7%	1980
October	1st to 10th	Night	25% 3 12% 23% 27% 9%	2110
	11th to 20th	Night	29% 2 7% 20% 31% 11%	2160
	21st to end	Night	35% 3 7% 22% 25% 9%	2376
November	1st to 10th	Night	26% 2 9% 25% 30% 8%	2220
	11th to 20th	Night	30% 3 7% 26% 25% 9%	2409
	21st to end	Night	34% 3 8% 22% 27% 6%	2470
December	1st to 10th	Night	36% 4 10% 26% 19% 4	2470
	11th to 20th	Night	40% 3 7% 21% 24% 4	3037
	21st to end	Night	47% 5% 8% 21% 15% 3	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	26% 17% 35% 18% 4	270
	11th to 20th	Day	27% 23% 37% 12% 2	252
	21st to end	Day	19% 27% 33% 16% 5%	264
February	1st to 10th	Day	27% 18% 42% 11% 3	240
	11th to 20th	Day	27% 24% 36% 12% 1	240
	21st to end	Day	35% 27% 28% 10% 1	198
March	1st to 10th	Day	22% 25% 36% 14% 3	240
	11th to 20th	Day	29% 19% 34% 17% 2	240
	21st to end	Day	28% 26% 32% 11% 3	264
April	1st to 10th	Day	15% 27% 35% 16% 6%	280
	11th to 20th	Day	23% 21% 35% 15% 5%	412
	21st to end	Day	24% 21% 33% 16% 6% 1	514
May	1st to 10th	Day	18% 18% 36% 22% 5% 1	603
	11th to 20th	Day	17% 10% 35% 27% 9% 2	625
	21st to end	Day	15% 9% 36% 20% 15% 4	679
June	1st to 10th	Day	7% 5% 20% 39% 23% 5%	630
	11th to 20th	Day	8% 3 28% 39% 18% 4	630
	21st to end	Day	4 3 31% 37% 20% 4	630
July	1st to 10th	Day	7% 3 15% 36% 28% 10%	621
	11th to 20th	Day	3 1 19% 41% 30% 6%	618
	21st to end	Day	8% 2 11% 36% 32% 11%	684
August	1st to 10th	Day	7% 3 15% 43% 26% 5%	626
	11th to 20th	Day	10% 3 15% 36% 30% 6%	615
	21st to end	Day	7% 3 13% 35% 33% 10%	534
September	1st to 10th	Day	8% 2 17% 33% 32% 8%	374
	11th to 20th	Day	6% 3 20% 42% 24% 5%	270
	21st to end	Day	12% 5% 23% 34% 21% 6%	270
October	1st to 10th	Day	12% 8% 37% 24% 16% 3	270
	11th to 20th	Day	13% 17% 41% 21% 8%	270
	21st to end	Day	26% 16% 33% 18% 5% 1	297
November	1st to 10th	Day	14% 14% 42% 20% 9% 1	270
	11th to 20th	Day	17% 19% 35% 20% 7% 1	270
	21st to end	Day	26% 15% 38% 17% 3	270
December	1st to 10th	Day	21% 19% 37% 15% 7% 2	270
	11th to 20th	Day	23% 17% 40% 13% 5% 1	270
	21st to end	Day	22% 24% 39% 12% 2	297
January	1st to 10th	Night	17% 19% 35% 24% 5%	950
	11th to 20th	Night	18% 19% 36% 23% 4	921
	21st to end	Night	16% 19% 35% 26% 4	990
February	1st to 10th	Night	21% 18% 37% 21% 3	900
	11th to 20th	Night	21% 21% 36% 19% 3	808
	21st to end	Night	21% 18% 37% 22% 2	522
March	1st to 10th	Night	17% 16% 36% 27% 4	540
	11th to 20th	Night	20% 16% 38% 23% 3	540
	21st to end	Night	18% 17% 40% 21% 4	594
April	1st to 10th	Night	16% 18% 40% 22% 5%	540
	11th to 20th	Night	17% 15% 36% 26% 6%	533
	21st to end	Night	19% 12% 41% 22% 6%	540
May	1st to 10th	Night	14% 10% 39% 31% 6%	540
	11th to 20th	Night	14% 9% 32% 32% 13% 1	531
	21st to end	Night	12% 7% 35% 26% 19% 2	584
June	1st to 10th	Night	8% 3 20% 41% 27% 2	540
	11th to 20th	Night	4 3 31% 42% 20% 1	540
	21st to end	Night	3 2 25% 47% 20% 3	540
July	1st to 10th	Night	6% 1 15% 44% 29% 4	525
	11th to 20th	Night	3 2 14% 44% 34% 3	522
	21st to end	Night	5% 1 14% 42% 34% 4	591
August	1st to 10th	Night	5% 2 15% 48% 28% 2	537
	11th to 20th	Night	7% 3 13% 46% 28% 4	534
	21st to end	Night	5% 2 14% 40% 35% 4	594
September	1st to 10th	Night	10% 2 15% 45% 26% 1	540
	11th to 20th	Night	11% 2 19% 41% 22% 4	540
	21st to end	Night	9% 4 21% 37% 26% 3	540
October	1st to 10th	Night	9% 4 30% 32% 21% 3	670
	11th to 20th	Night	14% 10% 37% 29% 9%	720
	21st to end	Night	19% 13% 30% 28% 10% 1	792
November	1st to 10th	Night	13% 12% 40% 24% 11% 1	740
	11th to 20th	Night	13% 17% 35% 27% 8%	889
	21st to end	Night	20% 17% 34% 22% 7%	950
December	1st to 10th	Night	17% 17% 35% 27% 6%	950
	11th to 20th	Night	21% 15% 35% 24% 4	950
	21st to end	Night	18% 19% 36% 23% 4	1045

Page generated at 2024-01-11 21:33:50. Version ac07

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