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 2024-11-30.

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	11% 6% 2 5% 4 4 4 3 5% 7% 48%	101504
	Night	11% 6% 2 5% 3 3 3 3 5% 7% 52%	98196
Transparency	Day	35% 4 11% 26% 20% 4	105168
	Night	32% 4 11% 25% 22% 6%	102659
Seeing	Day	15% 11% 28% 27% 15% 4	15540
	Night	14% 12% 31% 30% 12% 1	25395

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	13% 12% 4 4 3 3 3 3 4 6% 44%	2847
	11th to 20th	Day	9% 7% 2 7% 4 3 3 3 4 6% 53%	2850
	21st to end	Day	23% 11% 2 5% 2 3 2 2 3 5% 43%	3135
February	1st to 10th	Day	16% 10% 3 6% 5% 4 3 2 4 4 42%	1710
	11th to 20th	Day	15% 8% 3 5% 4 3 3 3 5% 6% 45%	1753
	21st to end	Day	16% 8% 3 6% 3 4 4 3 4 6% 43%	1642
March	1st to 10th	Day	14% 7% 2 5% 3 3 3 2 4 5% 51%	3436
	11th to 20th	Day	12% 6% 2 5% 3 3 3 3 5% 8% 50%	3480
	21st to end	Day	16% 10% 3 8% 5% 4 4 3 5% 6% 35%	3814
April	1st to 10th	Day	11% 7% 2 6% 5% 4 4 4 6% 7% 44%	2133
	11th to 20th	Day	14% 6% 3 6% 5% 4 4 4 5% 6% 43%	2254
	21st to end	Day	18% 9% 3 7% 4 3 3 3 4 6% 40%	2380
May	1st to 10th	Day	21% 8% 3 7% 4 4 3 3 4 6% 38%	4082
	11th to 20th	Day	11% 6% 2 7% 5% 4 5% 4 6% 8% 42%	4082
	21st to end	Day	14% 7% 2 7% 5% 4 6% 5% 7% 8% 35%	4477
June	1st to 10th	Day	7% 4 2 6% 5% 5% 5% 5% 7% 8% 47%	2470
	11th to 20th	Day	7% 3 2 5% 4 5% 5% 4 6% 9% 50%	2470
	21st to end	Day	5% 3 1 4 3 4 5% 4 7% 8% 57%	2470
July	1st to 10th	Day	8% 4 2 5% 4 5% 5% 5% 7% 10% 45%	4120
	11th to 20th	Day	4 4 2 4 4 4 4 3 6% 10% 54%	4120
	21st to end	Day	6% 4 1 5% 4 4 5% 4 7% 12% 48%	4465
August	1st to 10th	Day	4 3 2 4 3 3 3 4 6% 9% 59%	4104
	11th to 20th	Day	7% 4 2 5% 4 4 5% 4 7% 9% 49%	4041
	21st to end	Day	4 4 2 4 3 4 5% 4 6% 8% 57%	4247
September	1st to 10th	Day	10% 5% 2 4 3 3 4 3 5% 7% 54%	2199
	11th to 20th	Day	11% 4 1 5% 4 3 5% 4 6% 8% 48%	2090
	21st to end	Day	7% 4 2 5% 4 3 4 4 5% 7% 55%	2090
October	1st to 10th	Day	11% 4 2 3 3 4 3 3 5% 7% 57%	1933
	11th to 20th	Day	12% 4 2 4 2 2 3 2 3 4 63%	1900
	21st to end	Day	17% 5% 2 5% 2 2 2 2 3 5% 53%	2090
November	1st to 10th	Day	11% 4 2 4 3 3 3 2 4 6% 58%	1958
	11th to 20th	Day	12% 6% 2 4 3 3 3 3 3 6% 56%	1860
	21st to end	Day	14% 8% 2 3 2 2 2 3 4 8% 51%	1796
December	1st to 10th	Day	14% 7% 2 6% 4 4 3 3 5% 5% 47%	1710
	11th to 20th	Day	14% 9% 3 7% 5% 3 3 2 5% 6% 44%	2161
	21st to end	Day	18% 15% 5% 7% 4 4 3 3 4 5% 31%	3135
January	1st to 10th	Night	11% 8% 4 7% 4 3 3 4 5% 6% 45%	4108
	11th to 20th	Night	10% 5% 2 5% 3 3 3 3 4 6% 55%	4120
	21st to end	Night	22% 8% 3 4 3 2 2 2 3 5% 45%	4532
February	1st to 10th	Night	14% 9% 2 7% 3 4 3 3 5% 6% 44%	2470
	11th to 20th	Night	14% 8% 3 6% 3 3 2 2 4 5% 50%	2328
	21st to end	Night	15% 7% 2 5% 3 4 4 3 3 5% 49%	1810
March	1st to 10th	Night	14% 7% 2 6% 3 3 4 3 4 5% 47%	3419
	11th to 20th	Night	12% 6% 2 4 3 3 3 2 5% 6% 54%	3480
	21st to end	Night	13% 7% 2 7% 4 4 3 3 5% 6% 46%	3817
April	1st to 10th	Night	12% 6% 2 4 3 3 3 3 5% 6% 52%	2047
	11th to 20th	Night	14% 6% 2 5% 3 3 3 3 5% 6% 50%	1875
	21st to end	Night	17% 6% 2 7% 4 3 3 3 4 5% 47%	1796
May	1st to 10th	Night	15% 7% 2 6% 4 4 4 3 4 7% 44%	2823
	11th to 20th	Night	14% 6% 2 7% 4 3 4 3 5% 7% 44%	2823
	21st to end	Night	12% 6% 2 5% 5% 4 4 4 7% 9% 43%	3090
June	1st to 10th	Night	6% 4 1 5% 3 4 5% 4 6% 9% 54%	1710
	11th to 20th	Night	3 3 1 4 3 4 4 5% 6% 11% 56%	1710
	21st to end	Night	4 2 1 3 3 3 4 3 6% 8% 64%	1710
July	1st to 10th	Night	8% 5% 2 4 3 3 3 4 6% 9% 52%	2850
	11th to 20th	Night	3 2 1 4 3 3 4 3 5% 10% 62%	2850
	21st to end	Night	6% 4 2 4 3 3 4 3 6% 10% 56%	3098
August	1st to 10th	Night	2 2 1 3 3 3 4 4 7% 10% 62%	2836
	11th to 20th	Night	5% 4 2 5% 4 5% 5% 5% 6% 8% 52%	2798
	21st to end	Night	3 3 1 3 3 3 4 3 5% 9% 63%	3409
September	1st to 10th	Night	7% 4 2 4 3 2 5% 3 4 7% 59%	1977
	11th to 20th	Night	9% 4 2 6% 3 4 4 3 5% 7% 53%	2090
	21st to end	Night	8% 3 1 5% 3 3 3 4 4 6% 59%	2090
October	1st to 10th	Night	7% 3 1 4 3 3 3 2 4 7% 63%	2228
	11th to 20th	Night	12% 4 1 3 3 3 3 3 4 5% 60%	2280
	21st to end	Night	15% 6% 1 4 2 3 3 3 3 5% 55%	2508
November	1st to 10th	Night	12% 5% 1 3 2 2 2 2 3 5% 62%	2340
	11th to 20th	Night	9% 6% 2 4 3 2 3 3 3 5% 59%	2536
	21st to end	Night	13% 6% 2 5% 3 2 2 3 4 5% 55%	2600
December	1st to 10th	Night	13% 6% 2 5% 3 4 4 3 4 6% 50%	2470
	11th to 20th	Night	13% 7% 3 7% 4 4 3 2 4 6% 47%	3036
	21st to end	Night	17% 10% 4 7% 4 3 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	43% 3 8% 26% 19% 2	2848
	11th to 20th	Day	34% 3 15% 29% 15% 4	2850
	21st to end	Day	47% 2 8% 21% 20% 2	3135
February	1st to 10th	Day	46% 3 10% 22% 15% 3	1710
	11th to 20th	Day	42% 3 9% 25% 17% 3	1762
	21st to end	Day	44% 3 7% 22% 17% 8%	1642
March	1st to 10th	Day	36% 3 7% 22% 22% 10%	3436
	11th to 20th	Day	36% 3 13% 26% 20% 3	3480
	21st to end	Day	50% 4 10% 25% 10% 1	3814
April	1st to 10th	Day	39% 5% 11% 22% 17% 6%	2133
	11th to 20th	Day	42% 4 12% 21% 16% 5%	2254
	21st to end	Day	46% 4 9% 23% 16% 1	2380
May	1st to 10th	Day	48% 4 8% 22% 16% 2	4120
	11th to 20th	Day	40% 5% 15% 24% 17%	4086
	21st to end	Day	45% 6% 14% 19% 13% 2	4489
June	1st to 10th	Day	33% 7% 15% 27% 16% 2	2470
	11th to 20th	Day	31% 6% 14% 31% 17% 2	2470
	21st to end	Day	23% 6% 16% 31% 19% 5%	2470
July	1st to 10th	Day	31% 6% 17% 28% 14% 2	4056
	11th to 20th	Day	24% 5% 12% 36% 21% 2	4051
	21st to end	Day	26% 7% 19% 32% 15% 1	4325
August	1st to 10th	Day	22% 5% 13% 29% 26% 5%	4090
	11th to 20th	Day	30% 6% 20% 25% 17% 2	4080
	21st to end	Day	24% 5% 13% 41% 13% 3	4246
September	1st to 10th	Day	29% 5% 10% 25% 22% 10%	2199
	11th to 20th	Day	33% 5% 12% 22% 22% 5%	2090
	21st to end	Day	29% 5% 8% 23% 28% 6%	2090
October	1st to 10th	Day	17% 3 8% 16% 43% 14%	3206
	11th to 20th	Day	16% 2 4 20% 44% 15%	3140
	21st to end	Day	28% 2 8% 28% 28% 6%	3428
November	1st to 10th	Day	30% 3 9% 26% 26% 8%	1958
	11th to 20th	Day	33% 2 7% 27% 23% 8%	1860
	21st to end	Day	35% 3 9% 25% 24% 4	1796
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	40% 4 9% 25% 20% 3	4108
	11th to 20th	Night	33% 3 17% 22% 22% 2	4120
	21st to end	Night	44% 2 10% 20% 21% 3	4532
February	1st to 10th	Night	42% 3 11% 22% 18% 4	2470
	11th to 20th	Night	39% 2 8% 26% 20% 5%	2329
	21st to end	Night	40% 3 6% 20% 24% 8%	1810
March	1st to 10th	Night	39% 4 8% 20% 17% 11%	3419
	11th to 20th	Night	32% 3 10% 30% 20% 5%	3480
	21st to end	Night	39% 4 12% 31% 13% 2	3817
April	1st to 10th	Night	33% 4 9% 23% 21% 9%	2047
	11th to 20th	Night	36% 4 9% 24% 20% 8%	1875
	21st to end	Night	40% 4 9% 23% 21% 3	1796
May	1st to 10th	Night	41% 4 12% 21% 17% 4	2850
	11th to 20th	Night	40% 4 14% 24% 16% 2	2824
	21st to end	Night	36% 6% 16% 24% 16% 1	3099
June	1st to 10th	Night	27% 4 17% 30% 19% 3	1710
	11th to 20th	Night	22% 6% 15% 33% 22% 3	1710
	21st to end	Night	18% 5% 13% 31% 25% 7%	1710
July	1st to 10th	Night	28% 6% 17% 26% 18% 5%	2805
	11th to 20th	Night	17% 5% 11% 38% 25% 3	2796
	21st to end	Night	22% 6% 17% 38% 17% 2	2999
August	1st to 10th	Night	16% 5% 14% 31% 27% 6%	2826
	11th to 20th	Night	27% 7% 17% 26% 19% 3	2825
	21st to end	Night	19% 4 11% 40% 22% 5%	3409
September	1st to 10th	Night	25% 5% 9% 26% 24% 11%	1977
	11th to 20th	Night	31% 4 10% 24% 24% 7%	2090
	21st to end	Night	26% 4 7% 25% 31% 7%	2090
October	1st to 10th	Night	14% 2 7% 14% 37% 27%	3722
	11th to 20th	Night	20% 2 5% 17% 37% 19%	3779
	21st to end	Night	28% 4 7% 26% 27% 8%	4120
November	1st to 10th	Night	28% 2 8% 25% 29% 9%	2340
	11th to 20th	Night	30% 3 7% 25% 25% 10%	2536
	21st to end	Night	33% 3 8% 24% 27% 6%	2600
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% 21% 37% 12% 2	270
	21st to end	Day	21% 25% 34% 15% 5%	297
February	1st to 10th	Day	29% 17% 41% 10% 3	270
	11th to 20th	Day	27% 23% 36% 13% 1	270
	21st to end	Day	33% 28% 29% 9%	225
March	1st to 10th	Day	21% 23% 37% 16% 3	270
	11th to 20th	Day	27% 21% 34% 16% 2	270
	21st to end	Day	29% 25% 32% 11% 3	297
April	1st to 10th	Day	19% 27% 34% 14% 6%	313
	11th to 20th	Day	23% 23% 35% 14% 5%	452
	21st to end	Day	24% 21% 32% 16% 6% 1	560
May	1st to 10th	Day	18% 18% 36% 22% 5% 1	653
	11th to 20th	Day	17% 11% 34% 27% 9% 2	675
	21st to end	Day	15% 10% 35% 21% 14% 4	734
June	1st to 10th	Day	7% 6% 22% 38% 22% 4	680
	11th to 20th	Day	8% 3 28% 39% 19% 4	680
	21st to end	Day	4 4 30% 38% 20% 4	680
July	1st to 10th	Day	7% 3 16% 36% 28% 10%	671
	11th to 20th	Day	3 1 19% 42% 28% 6%	668
	21st to end	Day	8% 2 12% 37% 31% 11%	739
August	1st to 10th	Day	7% 2 16% 43% 27% 6%	676
	11th to 20th	Day	10% 3 16% 37% 29% 5%	665
	21st to end	Day	7% 3 12% 34% 34% 10%	580
September	1st to 10th	Day	8% 2 17% 33% 31% 8%	409
	11th to 20th	Day	6% 3 22% 42% 22% 5%	300
	21st to end	Day	12% 5% 23% 35% 19% 6%	300
October	1st to 10th	Day	11% 7% 34% 27% 17% 4	300
	11th to 20th	Day	12% 15% 38% 26% 8%	300
	21st to end	Day	25% 16% 34% 19% 6% 1	330
November	1st to 10th	Day	16% 14% 39% 21% 9% 1	300
	11th to 20th	Day	17% 19% 35% 20% 7% 2	300
	21st to end	Day	24% 16% 38% 18% 3	299
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% 20% 36% 22% 4	950
	21st to end	Night	17% 18% 34% 27% 4	1045
February	1st to 10th	Night	21% 19% 37% 21% 3	950
	11th to 20th	Night	21% 21% 35% 21% 3	854
	21st to end	Night	21% 19% 37% 21% 2	554
March	1st to 10th	Night	17% 16% 37% 27% 4	570
	11th to 20th	Night	19% 17% 37% 24% 2	570
	21st to end	Night	19% 17% 39% 20% 5%	627
April	1st to 10th	Night	17% 17% 39% 22% 5%	570
	11th to 20th	Night	17% 16% 37% 24% 6%	563
	21st to end	Night	20% 12% 40% 22% 7%	570
May	1st to 10th	Night	14% 10% 39% 30% 6%	570
	11th to 20th	Night	13% 9% 32% 32% 14% 1	561
	21st to end	Night	12% 7% 34% 26% 18% 1	617
June	1st to 10th	Night	8% 3 21% 41% 26% 2	570
	11th to 20th	Night	3 2 31% 43% 19% 1	570
	21st to end	Night	4 2 25% 48% 19% 2	570
July	1st to 10th	Night	6% 2 15% 45% 28% 4	555
	11th to 20th	Night	3 2 14% 46% 32% 3	552
	21st to end	Night	5% 1 14% 42% 33% 4	624
August	1st to 10th	Night	5% 2 16% 47% 29% 2	567
	11th to 20th	Night	8% 3 13% 46% 27% 3	564
	21st to end	Night	4 2 14% 41% 36% 4	627
September	1st to 10th	Night	9% 2 15% 45% 27% 1	570
	11th to 20th	Night	10% 2 19% 42% 21% 4	570
	21st to end	Night	9% 4 21% 37% 25% 3	570
October	1st to 10th	Night	8% 4 29% 34% 21% 3	708
	11th to 20th	Night	14% 9% 37% 31% 9%	760
	21st to end	Night	19% 13% 29% 28% 10% 1	836
November	1st to 10th	Night	14% 12% 39% 24% 10% 1	780
	11th to 20th	Night	13% 17% 35% 27% 8%	936
	21st to end	Night	19% 16% 35% 22% 7%	1000
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 2024-11-27 16:30:54. Version ac07

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