Keota Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Keota Star Party clear sky chart from 2005-11-06 to 2026-02-01.

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	5% 5% 2 5% 4 4 4 4 6% 8% 53%	136271
	Night	5% 6% 2 6% 4 4 4 4 6% 7% 52%	133203
Transparency	Day	28% 5% 10% 25% 23% 9%	131190
	Night	30% 5% 11% 25% 22% 7%	129291
Seeing	Day	8% 8% 27% 31% 20% 6%	17330
	Night	9% 8% 32% 39% 12% 1	27441

By Month

Percentage Cloud Cover SW (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	2 9% 3 8% 4 5% 4 3 4 6% 53%	3718
	11th to 20th	Day	1 5% 2 8% 6% 5% 4 4 6% 8% 51%	3720
	21st to end	Day	1 5% 2 5% 3 3 3 3 5% 7% 62%	4468
February	1st to 10th	Day	3 9% 3 9% 6% 4 4 4 5% 7% 46%	1815
	11th to 20th	Day	3 7% 3 7% 5% 4 4 4 6% 7% 49%	1949
	21st to end	Day	3 8% 3 7% 4 4 4 4 5% 6% 54%	1650
March	1st to 10th	Day	3 8% 3 7% 3 3 4 4 5% 7% 53%	4500
	11th to 20th	Day	5% 7% 2 6% 4 4 4 3 5% 7% 53%	4760
	21st to end	Day	5% 8% 3 7% 5% 5% 5% 4 7% 9% 44%	5925
April	1st to 10th	Day	8% 7% 2 5% 4 4 5% 4 5% 8% 49%	2400
	11th to 20th	Day	11% 9% 2 6% 4 4 5% 3 5% 7% 43%	2371
	21st to end	Day	11% 7% 2 5% 5% 3 5% 4 6% 7% 44%	2420
May	1st to 10th	Day	8% 7% 2 7% 5% 5% 4 4 5% 6% 48%	5900
	11th to 20th	Day	6% 4 2 5% 4 5% 5% 5% 7% 9% 48%	6204
	21st to end	Day	11% 6% 2 5% 4 4 5% 4 6% 8% 46%	6925
June	1st to 10th	Day	6% 3 1 4 3 4 4 5% 7% 11% 54%	2800
	11th to 20th	Day	6% 3 1 5% 4 4 5% 4 6% 8% 54%	2800
	21st to end	Day	4 3 1 4 4 4 5% 4 7% 9% 56%	2800
July	1st to 10th	Day	5% 3 1 5% 3 4 5% 4 6% 8% 56%	6339
	11th to 20th	Day	3 3 1 4 4 4 6% 5% 8% 11% 50%	6340
	21st to end	Day	4 3 2 6% 4 5% 6% 5% 7% 8% 50%	6903
August	1st to 10th	Day	8% 3 1 4 4 4 5% 5% 7% 11% 48%	5885
	11th to 20th	Day	2 3 1 3 3 4 4 4 7% 9% 59%	5366
	21st to end	Day	7% 5% 2 6% 4 4 5% 4 6% 8% 48%	5984
September	1st to 10th	Day	5% 4 1 4 3 2 3 3 5% 7% 64%	2400
	11th to 20th	Day	6% 3 1 3 4 4 4 3 5% 8% 61%	2331
	21st to end	Day	8% 3 2 3 2 3 2 2 4 6% 64%	2200
October	1st to 10th	Day	5% 3 1 3 1 2 2 2 3 4 75%	3406
	11th to 20th	Day	4 4 2 5% 3 2 3 2 4 6% 64%	3250
	21st to end	Day	7% 6% 2 4 2 3 2 2 5% 8% 59%	3291
November	1st to 10th	Day	3 4 2 4 3 3 3 3 5% 9% 59%	1853
	11th to 20th	Day	3 6% 2 3 3 4 3 3 6% 7% 60%	1890
	21st to end	Day	3 6% 2 5% 4 3 4 3 4 6% 59%	1810
December	1st to 10th	Day	2 3 2 6% 3 3 3 3 4 6% 65%	2700
	11th to 20th	Day	2 7% 2 5% 3 4 4 3 5% 6% 59%	3106
	21st to end	Day	4 7% 3 7% 4 4 4 3 6% 9% 49%	4092
January	1st to 10th	Night	3 8% 3 8% 4 4 4 3 5% 8% 50%	6467
	11th to 20th	Night	1 6% 3 7% 5% 4 4 4 6% 8% 52%	6480
	21st to end	Night	2 6% 2 7% 4 4 4 3 4 6% 58%	6781
February	1st to 10th	Night	4 9% 4 7% 5% 4 4 4 5% 7% 47%	2584
	11th to 20th	Night	3 8% 3 8% 6% 5% 5% 4 6% 6% 47%	2338
	21st to end	Night	3 8% 3 6% 4 4 4 3 4 6% 55%	1980
March	1st to 10th	Night	4 10% 3 7% 4 3 3 3 4 5% 54%	5374
	11th to 20th	Night	6% 8% 3 6% 4 3 4 3 4 5% 54%	5227
	21st to end	Night	9% 10% 3 6% 4 5% 4 4 6% 7% 42%	5030
April	1st to 10th	Night	8% 8% 3 6% 5% 3 3 4 5% 6% 49%	2000
	11th to 20th	Night	12% 8% 3 6% 4 4 3 3 4 7% 45%	1977
	21st to end	Night	14% 9% 3 5% 4 4 4 4 6% 7% 41%	1980
May	1st to 10th	Night	10% 7% 3 7% 4 4 5% 4 6% 7% 44%	4080
	11th to 20th	Night	9% 5% 2 6% 4 5% 5% 4 6% 9% 46%	3707
	21st to end	Night	14% 7% 2 6% 4 4 4 4 6% 7% 41%	3972
June	1st to 10th	Night	6% 3 1 5% 3 3 4 5% 9% 11% 50%	1600
	11th to 20th	Night	7% 4 2 4 4 4 4 4 6% 8% 54%	1600
	21st to end	Night	5% 4 2 6% 4 5% 6% 4 7% 8% 50%	1600
July	1st to 10th	Night	4 3 2 5% 4 4 5% 4 6% 8% 55%	3640
	11th to 20th	Night	4 4 2 5% 4 4 6% 5% 8% 10% 48%	3640
	21st to end	Night	5% 4 2 6% 4 5% 6% 5% 8% 9% 46%	3970
August	1st to 10th	Night	9% 4 2 6% 5% 5% 6% 5% 8% 8% 42%	3920
	11th to 20th	Night	2 5% 2 6% 5% 5% 6% 5% 7% 8% 49%	4483
	21st to end	Night	7% 6% 2 6% 4 4 5% 5% 7% 9% 44%	4993
September	1st to 10th	Night	6% 4 2 5% 4 3 4 4 6% 8% 55%	2000
	11th to 20th	Night	7% 4 1 4 3 3 4 4 5% 7% 57%	2067
	21st to end	Night	6% 4 1 4 3 3 3 3 5% 5% 63%	2200
October	1st to 10th	Night	6% 3 1 3 2 2 3 2 3 5% 70%	3778
	11th to 20th	Night	7% 4 2 5% 3 3 4 3 5% 6% 58%	3898
	21st to end	Night	6% 5% 2 4 3 3 3 3 5% 6% 60%	4475
November	1st to 10th	Night	4 5% 2 4 3 4 4 3 5% 7% 60%	2665
	11th to 20th	Night	4 5% 2 6% 4 3 3 3 4 7% 59%	2730
	21st to end	Night	4 7% 3 5% 4 3 4 3 5% 6% 56%	2808
December	1st to 10th	Night	2 4 1 5% 4 3 4 3 4 5% 65%	4710
	11th to 20th	Night	2 4 2 5% 4 3 4 4 6% 7% 59%	5321
	21st to end	Night	5% 9% 3 7% 4 3 4 4 6% 7% 47%	7128

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	32% 4 9% 31% 17% 6%	3719
	11th to 20th	Day	30% 5% 12% 24% 24% 5%	3720
	21st to end	Day	23% 4 12% 27% 27% 7%	4468
February	1st to 10th	Day	37% 4 11% 25% 17% 6%	1815
	11th to 20th	Day	34% 3 10% 27% 21% 4	1959
	21st to end	Day	31% 4 8% 26% 23% 8%	1650
March	1st to 10th	Day	28% 4 7% 20% 32% 8%	4500
	11th to 20th	Day	30% 4 11% 24% 27% 4	4760
	21st to end	Day	34% 8% 14% 30% 12% 2	5925
April	1st to 10th	Day	32% 5% 12% 25% 18% 7%	2400
	11th to 20th	Day	40% 5% 10% 21% 17% 7%	2374
	21st to end	Day	37% 6% 9% 29% 18% 2	2420
May	1st to 10th	Day	35% 6% 9% 28% 18% 4	5900
	11th to 20th	Day	29% 8% 11% 23% 24% 5%	6208
	21st to end	Day	33% 8% 12% 25% 19% 3	6926
June	1st to 10th	Day	24% 7% 18% 26% 17% 7%	2800
	11th to 20th	Day	27% 6% 10% 24% 23% 11%	2800
	21st to end	Day	23% 6% 9% 25% 25% 12%	2800
July	1st to 10th	Day	24% 5% 8% 18% 30% 14%	6271
	11th to 20th	Day	24% 6% 12% 27% 19% 12%	6265
	21st to end	Day	29% 6% 10% 19% 18% 18%	6705
August	1st to 10th	Day	30% 6% 15% 25% 16% 8%	4285
	11th to 20th	Day	24% 6% 11% 21% 24% 14%	3882
	21st to end	Day	23% 5% 9% 21% 26% 16%	4311
September	1st to 10th	Day	21% 4 6% 24% 28% 17%	2400
	11th to 20th	Day	22% 5% 7% 21% 30% 15%	2331
	21st to end	Day	23% 4 6% 23% 35% 11%	2200
October	1st to 10th	Day	16% 3 5% 18% 32% 26%	3406
	11th to 20th	Day	23% 3 8% 29% 27% 10%	3250
	21st to end	Day	25% 2 7% 27% 29% 9%	3291
November	1st to 10th	Day	23% 4 10% 27% 26% 10%	1853
	11th to 20th	Day	24% 3 8% 28% 30% 8%	1890
	21st to end	Day	27% 3 9% 27% 26% 8%	1810
December	1st to 10th	Day	21% 3 7% 34% 28% 7%	2700
	11th to 20th	Day	25% 4 8% 33% 25% 5%	3104
	21st to end	Day	31% 6% 11% 28% 19% 5%	4092
January	1st to 10th	Night	32% 5% 11% 27% 19% 6%	6467
	11th to 20th	Night	29% 5% 11% 22% 26% 8%	6480
	21st to end	Night	27% 5% 11% 26% 24% 7%	6781
February	1st to 10th	Night	36% 5% 12% 23% 18% 5%	2584
	11th to 20th	Night	35% 5% 11% 25% 19% 4	2338
	21st to end	Night	31% 3 8% 24% 24% 9%	1980
March	1st to 10th	Night	33% 4 5% 18% 31% 10%	5374
	11th to 20th	Night	32% 4 10% 17% 29% 7%	5227
	21st to end	Night	38% 7% 14% 26% 13% 1	5030
April	1st to 10th	Night	34% 6% 9% 25% 19% 7%	2000
	11th to 20th	Night	39% 5% 11% 22% 18% 5%	1977
	21st to end	Night	41% 6% 10% 23% 18% 2	1980
May	1st to 10th	Night	37% 8% 12% 29% 10% 3	4080
	11th to 20th	Night	33% 8% 14% 24% 16% 5%	3708
	21st to end	Night	40% 9% 15% 21% 12% 3	3972
June	1st to 10th	Night	25% 9% 22% 27% 13% 4	1600
	11th to 20th	Night	28% 8% 12% 24% 18% 10%	1600
	21st to end	Night	29% 7% 11% 25% 22% 6%	1600
July	1st to 10th	Night	25% 5% 12% 23% 28% 6%	3600
	11th to 20th	Night	28% 6% 19% 23% 19% 5%	3592
	21st to end	Night	31% 7% 13% 22% 19% 8%	3856
August	1st to 10th	Night	40% 7% 16% 20% 14% 3	2844
	11th to 20th	Night	33% 8% 14% 21% 15% 9%	3243
	21st to end	Night	25% 6% 16% 22% 22% 9%	3597
September	1st to 10th	Night	26% 5% 9% 23% 24% 13%	2000
	11th to 20th	Night	25% 5% 8% 25% 24% 12%	2067
	21st to end	Night	23% 4 8% 25% 28% 12%	2200
October	1st to 10th	Night	18% 4 6% 19% 28% 24%	3778
	11th to 20th	Night	26% 3 10% 27% 25% 8%	3898
	21st to end	Night	26% 3 9% 27% 25% 11%	4475
November	1st to 10th	Night	24% 4 10% 25% 26% 10%	2665
	11th to 20th	Night	25% 4 9% 27% 27% 9%	2730
	21st to end	Night	29% 3 9% 26% 26% 7%	2808
December	1st to 10th	Night	22% 3 9% 33% 27% 6%	4710
	11th to 20th	Night	24% 3 7% 38% 24% 4	5322
	21st to end	Night	35% 5% 8% 26% 22% 3	7128

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	6% 9% 30% 38% 11% 4	330
	11th to 20th	Day	8% 12% 38% 32% 10% 1	330
	21st to end	Day	3 12% 43% 31% 8% 2	363
February	1st to 10th	Day	7% 13% 44% 32% 3 1	300
	11th to 20th	Day	7% 10% 39% 35% 8% 1	300
	21st to end	Day	6% 19% 37% 30% 8%	249
March	1st to 10th	Day	7% 11% 33% 29% 17% 2	300
	11th to 20th	Day	10% 13% 33% 29% 13% 2	390
	21st to end	Day	13% 14% 33% 30% 9% 1	550
April	1st to 10th	Day	15% 15% 34% 26% 9% 2	500
	11th to 20th	Day	17% 18% 32% 22% 9% 2	492
	21st to end	Day	16% 16% 26% 26% 12% 4	520
May	1st to 10th	Day	16% 12% 27% 26% 16% 3	703
	11th to 20th	Day	15% 9% 25% 27% 19% 5%	725
	21st to end	Day	12% 9% 26% 27% 21% 5%	789
June	1st to 10th	Day	6% 5% 22% 32% 25% 11%	730
	11th to 20th	Day	7% 6% 29% 32% 22% 4	730
	21st to end	Day	5% 4 24% 38% 23% 6%	730
July	1st to 10th	Day	8% 2 15% 31% 33% 10%	721
	11th to 20th	Day	4 2 16% 33% 36% 9%	718
	21st to end	Day	4 2 16% 32% 36% 10%	794
August	1st to 10th	Day	7% 2 16% 35% 34% 7%	609
	11th to 20th	Day	3 3 21% 33% 27% 13%	517
	21st to end	Day	5% 3 20% 36% 29% 9%	583
September	1st to 10th	Day	5% 2 22% 32% 27% 11%	530
	11th to 20th	Day	5% 4 20% 29% 31% 10%	461
	21st to end	Day	12% 2 20% 26% 24% 16%	330
October	1st to 10th	Day	9% 6% 24% 24% 25% 12%	330
	11th to 20th	Day	5% 10% 34% 29% 15% 8%	330
	21st to end	Day	11% 8% 30% 32% 14% 4	363
November	1st to 10th	Day	7% 10% 30% 35% 13% 5%	330
	11th to 20th	Day	6% 9% 35% 34% 14% 2	330
	21st to end	Day	9% 9% 25% 41% 12% 3	330
December	1st to 10th	Day	6% 15% 32% 30% 14% 2	330
	11th to 20th	Day	7% 11% 43% 33% 6%	330
	21st to end	Day	9% 12% 37% 32% 10%	363
January	1st to 10th	Night	7% 10% 34% 38% 10% 2	1050
	11th to 20th	Night	7% 12% 40% 33% 8% 1	1050
	21st to end	Night	6% 8% 44% 34% 7% 1	1003
February	1st to 10th	Night	10% 9% 43% 32% 7%	800
	11th to 20th	Night	7% 9% 44% 35% 5%	784
	21st to end	Night	7% 12% 46% 31% 4	660
March	1st to 10th	Night	6% 11% 34% 41% 8%	800
	11th to 20th	Night	10% 8% 34% 37% 10% 1	800
	21st to end	Night	11% 11% 39% 31% 7% 1	680
April	1st to 10th	Night	13% 12% 37% 32% 5%	600
	11th to 20th	Night	17% 11% 34% 32% 6% 1	593
	21st to end	Night	19% 11% 28% 32% 10% 1	600
May	1st to 10th	Night	14% 12% 28% 32% 13% 1	600
	11th to 20th	Night	17% 7% 28% 34% 13% 1	591
	21st to end	Night	14% 5% 32% 34% 14% 1	650
June	1st to 10th	Night	7% 3 24% 45% 20% 1	600
	11th to 20th	Night	7% 5% 30% 46% 12% 1	600
	21st to end	Night	7% 4 26% 47% 17%	600
July	1st to 10th	Night	8% 2 17% 48% 25% 1	585
	11th to 20th	Night	5% 1 16% 48% 27% 2	582
	21st to end	Night	7% 2 14% 50% 27% 1	657
August	1st to 10th	Night	7% 2 16% 46% 27% 2	597
	11th to 20th	Night	5% 1 18% 50% 25%	594
	21st to end	Night	6% 2 18% 49% 24% 1	660
September	1st to 10th	Night	7% 3 18% 49% 21% 2	600
	11th to 20th	Night	8% 4 22% 45% 19% 3	600
	21st to end	Night	8% 3 27% 44% 17% 1	600
October	1st to 10th	Night	13% 6% 23% 38% 18% 2	710
	11th to 20th	Night	8% 7% 34% 36% 15% 1	800
	21st to end	Night	9% 10% 29% 39% 11% 1	1015
November	1st to 10th	Night	6% 6% 35% 40% 11% 2	1025
	11th to 20th	Night	7% 10% 33% 41% 8%	1050
	21st to end	Night	8% 9% 32% 41% 9% 1	1050
December	1st to 10th	Night	6% 10% 40% 38% 6%	1050
	11th to 20th	Night	7% 10% 39% 37% 6% 1	1050
	21st to end	Night	9% 11% 36% 37% 6% 1	1155

Page generated at 2026-01-28 23:21:47. Version ac07

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