Cimarron National Grasslands
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cimarron National Grasslands clear sky chart from 2005-11-06 to 2024-02-10.

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	6% 4 2 3 3 2 4 4 5% 7% 60%	78580
	Night	6% 4 2 4 4 2 4 4 5% 7% 59%	80433
Transparency	Day	24% 5% 11% 24% 25% 11%	78295
	Night	24% 6% 11% 23% 24% 11%	80241
Seeing	Day	8% 6% 27% 34% 20% 5%	14390
	Night	7% 7% 36% 38% 11%	24513

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	6% 11% 2 3 3 2 3 3 4 6% 56%	2538
	11th to 20th	Day	3 3 2 5% 5% 3 7% 5% 4 5% 56%	2540
	21st to end	Day	7% 6% 3 4 3 2 3 4 5% 7% 56%	3328
February	1st to 10th	Day	6% 7% 3 4 5% 3 4 3 3 6% 57%	1890
	11th to 20th	Day	4 7% 3 6% 5% 3 3 3 4 6% 57%	1749
	21st to end	Day	5% 6% 1 4 2 2 3 4 4 6% 63%	1480
March	1st to 10th	Day	5% 6% 3 4 2 2 3 4 5% 7% 59%	1800
	11th to 20th	Day	9% 5% 1 3 3 2 3 3 4 7% 60%	1890
	21st to end	Day	8% 5% 2 3 4 2 3 2 5% 7% 59%	2285
April	1st to 10th	Day	7% 3 2 3 3 2 3 4 3 7% 64%	2160
	11th to 20th	Day	10% 4 1 4 4 2 3 4 4 7% 57%	2131
	21st to end	Day	11% 5% 2 3 3 2 3 3 5% 7% 56%	2222
May	1st to 10th	Day	9% 4 2 4 3 2 4 4 4 7% 58%	2340
	11th to 20th	Day	8% 4 2 3 4 3 3 4 6% 7% 57%	2302
	21st to end	Day	6% 3 2 4 4 2 4 4 6% 9% 56%	2531
June	1st to 10th	Day	4 3 1 3 4 3 3 4 6% 10% 57%	2435
	11th to 20th	Day	5% 2 1 2 3 3 3 3 5% 8% 65%	2520
	21st to end	Day	3 3 1 2 3 2 4 4 6% 9% 62%	2520
July	1st to 10th	Day	5% 3 1 3 4 3 5% 6% 7% 9% 55%	2520
	11th to 20th	Day	3 2 1 3 3 3 4 4 6% 8% 63%	2520
	21st to end	Day	6% 2 2 3 4 3 5% 5% 7% 9% 55%	2567
August	1st to 10th	Day	4 2 1 3 3 3 5% 6% 8% 10% 54%	2263
	11th to 20th	Day	7% 3 2 4 3 2 5% 5% 5% 9% 56%	2123
	21st to end	Day	3 3 1 3 4 2 4 4 6% 9% 62%	2376
September	1st to 10th	Day	8% 3 2 3 4 2 3 4 5% 8% 59%	2156
	11th to 20th	Day	7% 4 1 3 3 2 3 3 4 6% 62%	1980
	21st to end	Day	6% 3 1 3 3 2 2 3 4 6% 68%	1980
October	1st to 10th	Day	11% 4 1 3 4 2 3 3 3 6% 60%	1980
	11th to 20th	Day	5% 3 1 2 2 1 2 2 3 5% 74%	1918
	21st to end	Day	8% 4 1 3 2 1 2 3 3 5% 67%	1782
November	1st to 10th	Day	4 3 2 2 3 1 3 3 3 5% 71%	1673
	11th to 20th	Day	4 5% 1 2 3 1 3 2 4 6% 69%	1710
	21st to end	Day	7% 5% 2 3 3 2 3 3 3 4 64%	1710
December	1st to 10th	Day	2 6% 2 5% 4 1 3 3 4 7% 62%	1710
	11th to 20th	Day	7% 4 2 2 2 2 3 4 5% 7% 62%	2157
	21st to end	Day	5% 8% 3 7% 5% 4 4 3 4 6% 51%	2794
January	1st to 10th	Night	5% 6% 2 5% 6% 3 3 4 4 6% 56%	4417
	11th to 20th	Night	3 5% 2 4 3 2 3 4 5% 7% 61%	4430
	21st to end	Night	6% 7% 3 5% 4 3 3 3 4 7% 56%	4364
February	1st to 10th	Night	5% 7% 3 5% 4 2 4 3 3 5% 59%	2274
	11th to 20th	Night	5% 5% 3 5% 5% 3 5% 4 5% 7% 53%	2098
	21st to end	Night	6% 5% 1 4 3 1 3 3 5% 6% 61%	1776
March	1st to 10th	Night	5% 5% 2 3 4 2 4 4 5% 7% 58%	2160
	11th to 20th	Night	8% 5% 1 3 3 2 3 4 5% 7% 59%	2070
	21st to end	Night	7% 5% 2 4 3 2 4 4 6% 8% 55%	2069
April	1st to 10th	Night	6% 4 2 3 4 2 4 3 4 7% 61%	1800
	11th to 20th	Night	9% 5% 2 3 3 2 3 4 5% 8% 54%	1777
	21st to end	Night	11% 5% 2 4 4 2 3 5% 5% 8% 52%	1738
May	1st to 10th	Night	10% 4 2 3 3 2 5% 3 6% 8% 54%	1620
	11th to 20th	Night	9% 4 1 3 4 2 5% 5% 6% 8% 53%	1593
	21st to end	Night	7% 4 2 4 5% 3 5% 5% 6% 7% 53%	1745
June	1st to 10th	Night	4 2 1 3 4 3 5% 7% 7% 10% 54%	1520
	11th to 20th	Night	3 2 1 3 4 3 5% 5% 7% 8% 60%	1440
	21st to end	Night	5% 3 1 4 4 3 4 6% 8% 12% 53%	1440
July	1st to 10th	Night	5% 3 2 4 4 3 5% 6% 8% 11% 51%	1440
	11th to 20th	Night	3 3 1 3 3 3 4 5% 8% 12% 56%	1440
	21st to end	Night	7% 3 2 5% 6% 4 6% 5% 7% 11% 44%	1749
August	1st to 10th	Night	5% 2 2 4 6% 4 6% 7% 7% 10% 46%	1672
	11th to 20th	Night	7% 3 1 4 5% 3 5% 5% 7% 10% 50%	1778
	21st to end	Night	4 3 1 3 4 2 4 5% 6% 9% 58%	1980
September	1st to 10th	Night	6% 3 1 3 3 2 3 4 5% 7% 61%	1802
	11th to 20th	Night	6% 4 1 4 4 2 3 5% 5% 7% 60%	1980
	21st to end	Night	6% 3 2 3 2 2 2 4 5% 6% 66%	1980
October	1st to 10th	Night	9% 4 1 4 3 2 3 4 5% 6% 61%	1980
	11th to 20th	Night	6% 3 1 2 2 2 2 3 3 4 73%	2034
	21st to end	Night	7% 4 1 2 2 2 2 4 3 5% 67%	2560
November	1st to 10th	Night	3 3 1 2 2 1 3 3 4 7% 71%	2405
	11th to 20th	Night	2 3 1 2 3 2 3 4 4 5% 72%	2470
	21st to end	Night	6% 4 2 4 3 1 3 4 3 6% 64%	2470
December	1st to 10th	Night	4 4 2 4 4 2 3 4 5% 6% 61%	2470
	11th to 20th	Night	5% 4 2 4 4 3 3 3 4 7% 62%	3036
	21st to end	Night	4 5% 2 5% 4 3 4 5% 6% 7% 55%	4856

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	29% 4 8% 26% 29% 4	2539
	11th to 20th	Day	26% 8% 12% 21% 23% 10%	2540
	21st to end	Day	28% 5% 9% 27% 27% 4	3328
February	1st to 10th	Day	31% 3 11% 22% 23% 11%	1890
	11th to 20th	Day	30% 4 8% 26% 20% 12%	1759
	21st to end	Day	23% 3 7% 21% 30% 16%	1480
March	1st to 10th	Day	24% 4 10% 21% 25% 17%	1800
	11th to 20th	Day	25% 4 11% 23% 27% 11%	1890
	21st to end	Day	25% 5% 12% 27% 23% 8%	2285
April	1st to 10th	Day	21% 4 9% 24% 26% 16%	2160
	11th to 20th	Day	27% 6% 10% 23% 22% 12%	2134
	21st to end	Day	27% 4 12% 24% 25% 8%	2222
May	1st to 10th	Day	27% 5% 9% 26% 22% 11%	2340
	11th to 20th	Day	26% 7% 16% 27% 19% 5%	2306
	21st to end	Day	24% 8% 15% 23% 20% 10%	2531
June	1st to 10th	Day	22% 7% 16% 26% 20% 8%	2435
	11th to 20th	Day	18% 5% 11% 22% 26% 17%	2520
	21st to end	Day	18% 5% 12% 27% 24% 13%	2520
July	1st to 10th	Day	23% 8% 13% 23% 24% 8%	2451
	11th to 20th	Day	17% 7% 11% 25% 30% 9%	2445
	21st to end	Day	24% 8% 17% 28% 20% 3	2424
August	1st to 10th	Day	21% 9% 20% 28% 16% 7%	2249
	11th to 20th	Day	25% 7% 12% 27% 21% 8%	2123
	21st to end	Day	19% 6% 13% 26% 26% 10%	2376
September	1st to 10th	Day	24% 5% 10% 22% 24% 14%	2156
	11th to 20th	Day	23% 4 8% 22% 27% 16%	1980
	21st to end	Day	19% 4 9% 24% 28% 15%	1980
October	1st to 10th	Day	27% 5% 9% 19% 28% 12%	1980
	11th to 20th	Day	17% 3 6% 20% 34% 21%	1918
	21st to end	Day	21% 3 8% 21% 32% 15%	1782
November	1st to 10th	Day	17% 3 8% 23% 33% 16%	1673
	11th to 20th	Day	19% 2 6% 27% 33% 13%	1710
	21st to end	Day	24% 4 7% 18% 30% 18%	1710
December	1st to 10th	Day	23% 4 11% 29% 25% 9%	1710
	11th to 20th	Day	21% 3 9% 24% 34% 10%	2155
	21st to end	Day	32% 6% 9% 19% 24% 10%	2794
January	1st to 10th	Night	29% 5% 9% 29% 24% 5%	4417
	11th to 20th	Night	22% 5% 15% 24% 24% 10%	4430
	21st to end	Night	29% 6% 11% 20% 29% 6%	4364
February	1st to 10th	Night	28% 4 10% 21% 25% 11%	2274
	11th to 20th	Night	31% 5% 9% 22% 23% 10%	2098
	21st to end	Night	24% 4 6% 20% 28% 18%	1776
March	1st to 10th	Night	25% 4 8% 22% 27% 15%	2160
	11th to 20th	Night	25% 6% 10% 23% 21% 15%	2070
	21st to end	Night	27% 7% 12% 24% 21% 10%	2069
April	1st to 10th	Night	24% 4 10% 22% 25% 16%	1800
	11th to 20th	Night	29% 4 13% 22% 21% 11%	1777
	21st to end	Night	29% 7% 14% 22% 21% 8%	1738
May	1st to 10th	Night	28% 8% 11% 21% 21% 11%	1620
	11th to 20th	Night	27% 10% 16% 20% 20% 6%	1594
	21st to end	Night	29% 11% 14% 21% 14% 11%	1746
June	1st to 10th	Night	21% 11% 19% 26% 15% 8%	1520
	11th to 20th	Night	20% 9% 14% 20% 23% 14%	1440
	21st to end	Night	22% 7% 15% 25% 19% 12%	1440
July	1st to 10th	Night	25% 9% 14% 25% 21% 6%	1400
	11th to 20th	Night	18% 8% 14% 26% 24% 9%	1392
	21st to end	Night	32% 7% 17% 25% 16% 3	1652
August	1st to 10th	Night	29% 10% 19% 22% 15% 6%	1662
	11th to 20th	Night	29% 8% 13% 29% 14% 8%	1778
	21st to end	Night	21% 8% 13% 23% 25% 9%	1980
September	1st to 10th	Night	22% 7% 13% 22% 22% 14%	1802
	11th to 20th	Night	22% 6% 12% 19% 25% 15%	1980
	21st to end	Night	18% 6% 9% 23% 29% 15%	1980
October	1st to 10th	Night	24% 6% 10% 20% 25% 15%	1980
	11th to 20th	Night	16% 3 7% 19% 32% 23%	2034
	21st to end	Night	20% 3 6% 24% 29% 18%	2560
November	1st to 10th	Night	15% 3 9% 22% 29% 22%	2405
	11th to 20th	Night	15% 4 7% 24% 34% 16%	2470
	21st to end	Night	23% 3 7% 20% 28% 20%	2470
December	1st to 10th	Night	23% 5% 10% 28% 25% 10%	2470
	11th to 20th	Night	23% 3 8% 24% 33% 9%	3037
	21st to end	Night	26% 6% 9% 25% 26% 8%	4856

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% 7% 30% 39% 11% 3	270
	11th to 20th	Day	9% 11% 30% 32% 15% 3	270
	21st to end	Day	6% 8% 36% 31% 17% 2	297
February	1st to 10th	Day	7% 10% 45% 30% 7% 1	267
	11th to 20th	Day	9% 8% 43% 25% 11% 3	240
	21st to end	Day	5% 10% 49% 31% 5%	198
March	1st to 10th	Day	7% 9% 40% 31% 12%	240
	11th to 20th	Day	13% 10% 35% 27% 13% 3	240
	21st to end	Day	15% 14% 34% 28% 8% 1	371
April	1st to 10th	Day	9% 11% 40% 26% 12% 1	420
	11th to 20th	Day	13% 16% 37% 27% 7% 1	412
	21st to end	Day	15% 15% 39% 22% 9% 1	482
May	1st to 10th	Day	9% 8% 37% 31% 12% 2	603
	11th to 20th	Day	12% 7% 30% 32% 17% 3	625
	21st to end	Day	9% 8% 34% 35% 14% 1	679
June	1st to 10th	Day	5% 5% 27% 35% 22% 7%	630
	11th to 20th	Day	4 3 33% 35% 21% 3	630
	21st to end	Day	4 3 23% 42% 23% 4	630
July	1st to 10th	Day	5% 2 14% 39% 34% 7%	621
	11th to 20th	Day	3 10% 42% 33% 11%	618
	21st to end	Day	6% 1 8% 36% 37% 12%	684
August	1st to 10th	Day	4 1 12% 37% 37% 10%	561
	11th to 20th	Day	2 2 19% 40% 32% 5%	437
	21st to end	Day	3 1 15% 43% 29% 9%	495
September	1st to 10th	Day	7% 2 15% 42% 28% 7%	446
	11th to 20th	Day	5% 17% 37% 29% 12%	270
	21st to end	Day	9% 3 21% 34% 24% 8%	270
October	1st to 10th	Day	14% 7% 21% 26% 23% 8%	270
	11th to 20th	Day	6% 4 31% 32% 18% 7%	270
	21st to end	Day	15% 8% 24% 27% 18% 7%	297
November	1st to 10th	Day	7% 6% 32% 30% 18% 6%	270
	11th to 20th	Day	5% 9% 29% 36% 19% 2	270
	21st to end	Day	12% 13% 24% 29% 16% 7%	270
December	1st to 10th	Day	3 7% 34% 38% 16% 2	270
	11th to 20th	Day	9% 8% 36% 30% 16% 1	270
	21st to end	Day	10% 13% 36% 32% 8%	297
January	1st to 10th	Night	5% 8% 37% 39% 9% 1	950
	11th to 20th	Night	8% 8% 35% 38% 11% 1	950
	21st to end	Night	6% 7% 36% 41% 9%	924
February	1st to 10th	Night	7% 10% 38% 37% 7%	758
	11th to 20th	Night	7% 9% 48% 30% 5%	704
	21st to end	Night	10% 9% 49% 28% 4	592
March	1st to 10th	Night	8% 11% 43% 33% 4	720
	11th to 20th	Night	10% 9% 39% 31% 10%	630
	21st to end	Night	8% 14% 51% 24% 3	594
April	1st to 10th	Night	9% 11% 47% 28% 4	540
	11th to 20th	Night	11% 14% 48% 24% 3	533
	21st to end	Night	13% 11% 45% 24% 8%	540
May	1st to 10th	Night	11% 10% 43% 31% 6%	540
	11th to 20th	Night	10% 8% 37% 34% 9% 1	531
	21st to end	Night	9% 9% 45% 30% 7%	584
June	1st to 10th	Night	4 5% 41% 38% 12%	540
	11th to 20th	Night	3 8% 49% 34% 6%	540
	21st to end	Night	4 3 37% 44% 11%	540
July	1st to 10th	Night	5% 2 25% 49% 19%	525
	11th to 20th	Night	4 1 23% 51% 21% 1	522
	21st to end	Night	6% 1 18% 53% 20%	591
August	1st to 10th	Night	6% 2 18% 51% 23%	537
	11th to 20th	Night	8% 1 24% 51% 16%	534
	21st to end	Night	5% 1 25% 46% 22% 2	594
September	1st to 10th	Night	7% 2 25% 52% 14%	540
	11th to 20th	Night	7% 2 38% 40% 12%	540
	21st to end	Night	6% 5% 33% 43% 14%	540
October	1st to 10th	Night	11% 6% 34% 39% 11%	540
	11th to 20th	Night	7% 8% 35% 39% 10% 2	594
	21st to end	Night	9% 7% 34% 32% 16% 1	976
November	1st to 10th	Night	4 6% 32% 47% 10% 1	925
	11th to 20th	Night	4 8% 38% 40% 10% 1	950
	21st to end	Night	7% 10% 29% 37% 15% 1	950
December	1st to 10th	Night	6% 8% 35% 41% 11%	950
	11th to 20th	Night	8% 7% 39% 37% 8%	950
	21st to end	Night	10% 11% 38% 34% 7%	1045

Page generated at 2024-02-07 05:11:56. Version ac07

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