Great Plains State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Great Plains State Park clear sky chart from 2005-11-06 to 2024-03-06.

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	8% 4 2 4 4 2 4 4 5% 7% 57%	78954
	Night	8% 4 2 4 3 2 3 4 5% 7% 58%	80638
Transparency	Day	28% 5% 10% 24% 25% 9%	78679
	Night	26% 4 9% 23% 27% 11%	80433
Seeing	Day	9% 8% 26% 32% 20% 4	14312
	Night	9% 8% 34% 36% 13% 1	24422

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	5% 7% 2 5% 4 3 3 4 4 7% 56%	2847
	11th to 20th	Day	6% 5% 1 2 2 2 3 4 4 6% 64%	2850
	21st to end	Day	13% 8% 3 5% 4 2 2 3 3 6% 50%	3171
February	1st to 10th	Day	8% 7% 3 5% 3 2 3 3 4 5% 56%	1900
	11th to 20th	Day	9% 5% 2 5% 4 2 3 4 4 6% 57%	1849
	21st to end	Day	10% 8% 2 4 4 3 4 3 3 4 55%	1570
March	1st to 10th	Day	11% 5% 2 4 3 2 4 4 5% 7% 53%	1912
	11th to 20th	Day	13% 7% 2 5% 3 3 3 2 4 5% 54%	1980
	21st to end	Day	8% 6% 3 4 4 3 4 3 4 7% 54%	2178
April	1st to 10th	Day	7% 4 2 4 3 2 3 4 4 7% 61%	1998
	11th to 20th	Day	12% 5% 2 5% 4 2 4 4 4 6% 52%	2134
	21st to end	Day	10% 4 2 4 4 2 4 4 5% 7% 55%	2338
May	1st to 10th	Day	10% 4 3 5% 5% 3 4 4 5% 6% 51%	2340
	11th to 20th	Day	10% 5% 3 4 4 2 3 4 5% 7% 53%	2302
	21st to end	Day	9% 4 3 5% 5% 4 5% 5% 6% 7% 48%	2531
June	1st to 10th	Day	6% 4 1 3 5% 3 4 6% 6% 10% 53%	2340
	11th to 20th	Day	4 2 1 3 4 2 5% 5% 6% 7% 60%	2340
	21st to end	Day	5% 2 1 3 3 2 3 4 5% 7% 64%	2340
July	1st to 10th	Day	7% 3 2 3 5% 3 5% 6% 7% 10% 49%	2340
	11th to 20th	Day	4 2 1 3 3 2 4 5% 5% 9% 62%	2340
	21st to end	Day	3 2 1 4 4 2 4 5% 6% 10% 58%	2546
August	1st to 10th	Day	4 2 1 3 5% 2 4 4 5% 8% 60%	2328
	11th to 20th	Day	6% 4 2 4 4 2 5% 6% 6% 9% 51%	2218
	21st to end	Day	4 2 1 2 4 3 4 6% 7% 9% 58%	2376
September	1st to 10th	Day	8% 3 2 4 3 2 4 4 5% 6% 60%	1996
	11th to 20th	Day	9% 5% 3 5% 5% 3 5% 4 4 8% 49%	1980
	21st to end	Day	8% 4 1 3 3 3 3 4 5% 6% 61%	1980
October	1st to 10th	Day	7% 3 2 4 3 2 4 3 5% 6% 62%	1980
	11th to 20th	Day	10% 3 1 3 3 1 2 3 3 4 68%	1854
	21st to end	Day	10% 3 2 3 3 2 3 2 3 4 64%	1980
November	1st to 10th	Day	6% 4 1 3 2 2 3 3 4 6% 65%	1690
	11th to 20th	Day	6% 3 1 2 3 1 3 3 4 4 70%	1710
	21st to end	Day	11% 4 1 4 2 2 3 3 4 6% 61%	1710
December	1st to 10th	Day	7% 4 2 5% 4 3 3 5% 4 5% 58%	1710
	11th to 20th	Day	8% 6% 2 4 4 2 4 3 5% 6% 53%	2161
	21st to end	Day	10% 7% 3 6% 5% 3 4 4 5% 6% 48%	3135
January	1st to 10th	Night	10% 5% 1 5% 4 3 4 4 4 6% 54%	4108
	11th to 20th	Night	4 3 2 3 3 3 3 4 4 6% 64%	4120
	21st to end	Night	11% 10% 3 4 3 2 3 3 3 5% 53%	4523
February	1st to 10th	Night	11% 5% 2 4 3 2 4 4 4 5% 56%	2280
	11th to 20th	Night	9% 6% 2 4 4 2 3 3 5% 7% 56%	2218
	21st to end	Night	8% 6% 2 4 4 2 3 3 4 7% 56%	1884
March	1st to 10th	Night	7% 3 2 5% 4 2 5% 4 5% 7% 55%	2162
	11th to 20th	Night	13% 5% 2 3 3 2 2 4 3 6% 57%	1980
	21st to end	Night	8% 4 2 4 4 2 3 5% 5% 7% 57%	2178
April	1st to 10th	Night	7% 3 2 3 3 2 4 4 5% 8% 59%	1958
	11th to 20th	Night	12% 4 1 5% 4 2 3 4 5% 8% 53%	1777
	21st to end	Night	10% 4 2 4 3 2 3 5% 4 7% 56%	1620
May	1st to 10th	Night	10% 4 2 3 3 3 5% 4 5% 7% 55%	1620
	11th to 20th	Night	8% 4 2 4 4 2 4 4 6% 9% 52%	1593
	21st to end	Night	6% 2 2 4 4 3 5% 6% 5% 9% 56%	1745
June	1st to 10th	Night	4 3 1 2 3 2 3 5% 7% 11% 59%	1620
	11th to 20th	Night	4 2 2 3 3 2 4 4 7% 11% 58%	1620
	21st to end	Night	4 2 2 3 3 2 3 3 5% 9% 65%	1620
July	1st to 10th	Night	3 3 2 4 4 2 4 5% 7% 13% 52%	1620
	11th to 20th	Night	2 3 1 2 3 2 4 4 6% 10% 63%	1620
	21st to end	Night	2 1 1 2 3 3 4 4 7% 10% 62%	1772
August	1st to 10th	Night	2 3 1 2 4 2 4 6% 8% 9% 60%	1611
	11th to 20th	Night	6% 3 2 4 4 3 4 6% 6% 11% 51%	1679
	21st to end	Night	3 2 1 3 3 3 4 5% 6% 11% 60%	1980
September	1st to 10th	Night	7% 4 2 4 4 2 3 4 4 8% 60%	1962
	11th to 20th	Night	9% 6% 3 5% 5% 2 4 4 4 7% 52%	1980
	21st to end	Night	7% 3 1 3 3 2 3 4 5% 6% 63%	1980
October	1st to 10th	Night	7% 3 1 3 3 2 4 4 5% 6% 61%	1980
	11th to 20th	Night	8% 4 2 3 3 2 2 3 3 4 68%	2088
	21st to end	Night	9% 5% 1 2 2 1 2 2 4 5% 65%	2376
November	1st to 10th	Night	6% 4 1 2 3 1 2 3 4 6% 68%	2386
	11th to 20th	Night	5% 3 1 3 3 2 3 3 4 6% 69%	2470
	21st to end	Night	10% 4 2 4 3 2 3 3 3 6% 61%	2470
December	1st to 10th	Night	8% 3 2 3 3 2 3 4 4 6% 63%	2470
	11th to 20th	Night	7% 6% 2 5% 4 2 4 4 5% 6% 56%	3036
	21st to end	Night	10% 6% 2 4 4 3 3 4 4 6% 54%	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	28% 4 8% 26% 28% 7%	2848
	11th to 20th	Day	21% 4 10% 24% 36% 5%	2850
	21st to end	Day	39% 2 5% 24% 25% 5%	3171
February	1st to 10th	Day	32% 3 7% 23% 28% 7%	1900
	11th to 20th	Day	30% 3 6% 26% 24% 10%	1859
	21st to end	Day	35% 2 5% 17% 28% 14%	1570
March	1st to 10th	Day	31% 4 8% 20% 21% 16%	1912
	11th to 20th	Day	34% 4 8% 23% 22% 10%	1980
	21st to end	Day	32% 4 11% 24% 21% 9%	2178
April	1st to 10th	Day	25% 4 11% 25% 23% 12%	1998
	11th to 20th	Day	34% 5% 8% 20% 22% 12%	2134
	21st to end	Day	29% 4 10% 24% 26% 6%	2338
May	1st to 10th	Day	34% 5% 9% 19% 22% 11%	2340
	11th to 20th	Day	31% 5% 13% 25% 21% 5%	2306
	21st to end	Day	35% 6% 13% 23% 19% 4	2531
June	1st to 10th	Day	27% 7% 16% 28% 16% 7%	2340
	11th to 20th	Day	22% 6% 12% 28% 25% 7%	2340
	21st to end	Day	20% 5% 12% 26% 27% 10%	2340
July	1st to 10th	Day	28% 9% 14% 29% 17% 3	2276
	11th to 20th	Day	19% 5% 10% 29% 30% 8%	2271
	21st to end	Day	20% 5% 12% 33% 25% 3	2405
August	1st to 10th	Day	21% 5% 13% 30% 24% 8%	2314
	11th to 20th	Day	27% 8% 13% 26% 20% 6%	2218
	21st to end	Day	21% 7% 14% 26% 24% 8%	2376
September	1st to 10th	Day	26% 6% 8% 23% 24% 14%	1996
	11th to 20th	Day	35% 5% 9% 19% 24% 7%	1980
	21st to end	Day	25% 5% 7% 23% 31% 9%	1980
October	1st to 10th	Day	24% 5% 12% 22% 27% 10%	1980
	11th to 20th	Day	23% 3 5% 20% 32% 17%	1854
	21st to end	Day	26% 3 6% 24% 26% 14%	1980
November	1st to 10th	Day	21% 3 8% 25% 28% 15%	1690
	11th to 20th	Day	18% 3 6% 29% 33% 11%	1710
	21st to end	Day	27% 2 6% 22% 30% 12%	1710
December	1st to 10th	Day	27% 4 10% 26% 26% 7%	1710
	11th to 20th	Day	32% 3 10% 17% 30% 8%	2159
	21st to end	Day	36% 4 6% 23% 24% 6%	3135
January	1st to 10th	Night	29% 5% 7% 26% 28% 6%	4108
	11th to 20th	Night	21% 3 13% 22% 32% 10%	4120
	21st to end	Night	36% 2 6% 21% 26% 9%	4523
February	1st to 10th	Night	31% 4 7% 22% 26% 10%	2280
	11th to 20th	Night	30% 3 6% 23% 25% 13%	2218
	21st to end	Night	30% 3 5% 18% 25% 19%	1884
March	1st to 10th	Night	29% 4 7% 19% 23% 18%	2162
	11th to 20th	Night	29% 4 7% 24% 22% 13%	1980
	21st to end	Night	26% 4 14% 23% 24% 8%	2178
April	1st to 10th	Night	24% 4 11% 21% 24% 16%	1958
	11th to 20th	Night	30% 4 9% 22% 22% 13%	1777
	21st to end	Night	29% 4 9% 27% 23% 8%	1620
May	1st to 10th	Night	29% 6% 9% 20% 25% 11%	1620
	11th to 20th	Night	30% 6% 16% 21% 20% 7%	1594
	21st to end	Night	26% 6% 16% 25% 21% 6%	1746
June	1st to 10th	Night	19% 6% 20% 31% 17% 7%	1620
	11th to 20th	Night	20% 6% 15% 27% 25% 7%	1620
	21st to end	Night	18% 4 10% 28% 28% 12%	1620
July	1st to 10th	Night	24% 7% 15% 30% 20% 4	1575
	11th to 20th	Night	15% 6% 8% 28% 32% 11%	1566
	21st to end	Night	16% 6% 12% 32% 28% 5%	1673
August	1st to 10th	Night	18% 5% 12% 26% 27% 11%	1601
	11th to 20th	Night	26% 6% 14% 24% 24% 5%	1679
	21st to end	Night	19% 5% 13% 27% 27% 9%	1980
September	1st to 10th	Night	25% 5% 9% 22% 27% 13%	1962
	11th to 20th	Night	34% 5% 9% 18% 25% 9%	1980
	21st to end	Night	22% 4 7% 24% 30% 13%	1980
October	1st to 10th	Night	24% 4 10% 23% 25% 14%	1980
	11th to 20th	Night	23% 3 4 18% 29% 23%	2088
	21st to end	Night	24% 2 6% 23% 28% 16%	2376
November	1st to 10th	Night	20% 3 7% 23% 31% 16%	2386
	11th to 20th	Night	19% 3 6% 25% 33% 14%	2470
	21st to end	Night	27% 3 6% 21% 28% 16%	2470
December	1st to 10th	Night	24% 2 9% 26% 28% 12%	2470
	11th to 20th	Night	30% 3 6% 19% 31% 11%	3037
	21st to end	Night	31% 5% 7% 20% 27% 9%	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	10% 14% 38% 28% 9% 2	270
	11th to 20th	Day	14% 19% 30% 28% 9%	270
	21st to end	Day	10% 13% 42% 27% 7%	297
February	1st to 10th	Day	14% 15% 39% 28% 4	270
	11th to 20th	Day	11% 17% 44% 21% 6%	270
	21st to end	Day	16% 21% 39% 18% 6%	225
March	1st to 10th	Day	11% 19% 36% 28% 5% 1	255
	11th to 20th	Day	18% 20% 37% 17% 7% 1	240
	21st to end	Day	12% 17% 45% 19% 6%	264
April	1st to 10th	Day	11% 20% 35% 26% 7%	258
	11th to 20th	Day	15% 18% 45% 20% 2	412
	21st to end	Day	14% 16% 38% 23% 8% 2	598
May	1st to 10th	Day	9% 11% 40% 31% 8%	603
	11th to 20th	Day	11% 10% 32% 30% 16% 2	625
	21st to end	Day	12% 6% 33% 31% 15% 4	679
June	1st to 10th	Day	7% 2 24% 38% 24% 5%	630
	11th to 20th	Day	6% 3 24% 45% 20% 2	630
	21st to end	Day	5% 1 18% 43% 25% 7%	630
July	1st to 10th	Day	5% 10% 35% 37% 11%	621
	11th to 20th	Day	2 2 9% 38% 40% 10%	618
	21st to end	Day	3 1 5% 36% 44% 12%	684
August	1st to 10th	Day	4 1 9% 42% 38% 6%	626
	11th to 20th	Day	8% 1 12% 38% 34% 7%	532
	21st to end	Day	5% 1 7% 36% 38% 13%	495
September	1st to 10th	Day	9% 1 6% 31% 38% 13%	286
	11th to 20th	Day	7% 1 11% 36% 36% 10%	270
	21st to end	Day	12% 3 14% 34% 27% 10%	270
October	1st to 10th	Day	6% 3 27% 34% 26% 4	270
	11th to 20th	Day	10% 10% 32% 32% 14% 1	270
	21st to end	Day	21% 8% 28% 27% 14% 2	297
November	1st to 10th	Day	11% 6% 37% 29% 14% 2	270
	11th to 20th	Day	11% 11% 32% 28% 14% 3	270
	21st to end	Day	16% 10% 38% 24% 12%	270
December	1st to 10th	Day	9% 10% 43% 27% 11%	270
	11th to 20th	Day	14% 12% 37% 28% 9% 1	270
	21st to end	Day	16% 15% 40% 23% 5%	297
January	1st to 10th	Night	9% 10% 39% 33% 8% 1	950
	11th to 20th	Night	9% 12% 35% 36% 8%	950
	21st to end	Night	9% 10% 37% 35% 8%	1036
February	1st to 10th	Night	13% 11% 39% 30% 6%	760
	11th to 20th	Night	12% 12% 43% 28% 6%	744
	21st to end	Night	13% 15% 44% 26% 3	628
March	1st to 10th	Night	9% 13% 41% 32% 5%	678
	11th to 20th	Night	17% 13% 38% 26% 6%	540
	21st to end	Night	9% 17% 44% 26% 4	594
April	1st to 10th	Night	8% 14% 49% 24% 5%	540
	11th to 20th	Night	14% 12% 50% 21% 2	533
	21st to end	Night	12% 13% 42% 27% 6% 1	540
May	1st to 10th	Night	10% 9% 49% 25% 6%	540
	11th to 20th	Night	10% 8% 40% 31% 11% 1	531
	21st to end	Night	7% 5% 39% 35% 13% 1	584
June	1st to 10th	Night	4 3 32% 42% 17% 1	540
	11th to 20th	Night	4 4 41% 44% 7%	540
	21st to end	Night	4 2 27% 48% 17% 1	540
July	1st to 10th	Night	6% 2 13% 46% 32% 2	525
	11th to 20th	Night	3 1 12% 54% 28% 2	522
	21st to end	Night	2 7% 58% 31% 2	591
August	1st to 10th	Night	3 1 12% 51% 32% 1	537
	11th to 20th	Night	5% 1 15% 48% 29% 1	534
	21st to end	Night	3 1 11% 47% 36% 2	594
September	1st to 10th	Night	8% 2 17% 43% 29% 1	540
	11th to 20th	Night	12% 2 22% 38% 24% 2	540
	21st to end	Night	7% 3 24% 44% 20% 2	540
October	1st to 10th	Night	8% 4 30% 41% 17% 1	540
	11th to 20th	Night	10% 6% 35% 37% 13%	648
	21st to end	Night	11% 9% 34% 33% 13% 1	792
November	1st to 10th	Night	8% 7% 36% 37% 10% 1	906
	11th to 20th	Night	7% 8% 38% 35% 11%	950
	21st to end	Night	12% 11% 34% 33% 10%	950
December	1st to 10th	Night	10% 10% 35% 36% 9%	950
	11th to 20th	Night	13% 10% 39% 33% 6%	950
	21st to end	Night	13% 11% 38% 33% 6%	1045

Page generated at 2024-03-03 05:28:53. Version ac07

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