Tallgrass Prairie National Preserve
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tallgrass Prairie National Preserve clear sky chart from 2005-11-06 to 2024-11-02.

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	10% 6% 2 6% 4 4 4 3 5% 7% 48%	101268
	Night	10% 6% 2 5% 3 3 4 3 5% 7% 51%	97822
Transparency	Day	35% 5% 12% 26% 18% 3	101081
	Night	33% 5% 12% 26% 20% 4	97680
Seeing	Day	14% 10% 30% 28% 15% 3	15616
	Night	13% 9% 34% 33% 11% 1	25453

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	12% 9% 3 10% 5% 5% 4 4 5% 6% 36%	2847
	11th to 20th	Day	10% 10% 3 8% 5% 7% 6% 3 4 6% 38%	2850
	21st to end	Day	11% 13% 5% 9% 4 3 4 2 4 6% 40%	3135
February	1st to 10th	Day	11% 11% 3 7% 5% 5% 3 3 3 7% 43%	1710
	11th to 20th	Day	8% 7% 3 8% 6% 5% 4 3 5% 6% 46%	1784
	21st to end	Day	9% 6% 4 6% 4 3 5% 3 5% 7% 47%	1570
March	1st to 10th	Day	11% 8% 2 5% 3 2 3 2 4 6% 54%	3402
	11th to 20th	Day	11% 5% 2 3 2 2 3 2 4 7% 59%	3480
	21st to end	Day	14% 8% 4 6% 4 4 4 3 5% 6% 41%	3814
April	1st to 10th	Day	11% 8% 2 5% 3 3 3 3 5% 6% 51%	2094
	11th to 20th	Day	13% 7% 3 7% 5% 4 4 3 5% 7% 43%	2333
	21st to end	Day	18% 8% 2 6% 4 3 4 3 5% 6% 41%	2470
May	1st to 10th	Day	19% 10% 3 7% 4 4 3 3 4 5% 38%	4082
	11th to 20th	Day	14% 6% 2 5% 4 4 4 3 5% 7% 45%	4082
	21st to end	Day	13% 6% 3 7% 5% 4 4 4 6% 7% 42%	4477
June	1st to 10th	Day	5% 3 1 5% 4 4 5% 4 7% 9% 52%	2470
	11th to 20th	Day	8% 4 1 5% 5% 4 4 3 6% 8% 51%	2470
	21st to end	Day	6% 3 1 4 4 4 4 4 6% 8% 55%	2470
July	1st to 10th	Day	11% 6% 2 5% 5% 4 5% 4 6% 8% 44%	4120
	11th to 20th	Day	6% 2 1 4 4 4 5% 4 7% 10% 53%	4120
	21st to end	Day	6% 4 2 6% 5% 5% 6% 5% 8% 10% 44%	4465
August	1st to 10th	Day	6% 5% 2 6% 4 4 4 3 5% 7% 53%	4104
	11th to 20th	Day	10% 5% 2 6% 4 4 4 3 5% 8% 49%	4041
	21st to end	Day	4 3 1 4 3 4 4 3 5% 8% 60%	4418
September	1st to 10th	Day	13% 4 2 4 3 3 4 3 5% 6% 54%	2125
	11th to 20th	Day	9% 5% 2 5% 3 4 4 4 5% 6% 54%	2090
	21st to end	Day	9% 5% 2 5% 4 3 4 3 5% 5% 55%	2090
October	1st to 10th	Day	11% 3 3 5% 3 3 4 3 4 7% 54%	1981
	11th to 20th	Day	10% 5% 1 4 2 2 2 2 4 5% 63%	1900
	21st to end	Day	13% 7% 2 5% 3 2 3 3 4 4 54%	2090
November	1st to 10th	Day	7% 5% 2 5% 3 3 3 3 4 7% 59%	1758
	11th to 20th	Day	9% 6% 1 4 3 3 3 3 4 6% 57%	1710
	21st to end	Day	14% 5% 2 5% 3 3 3 2 4 5% 56%	1710
December	1st to 10th	Day	10% 6% 2 5% 4 3 4 3 6% 7% 49%	1710
	11th to 20th	Day	10% 7% 4 7% 5% 4 4 3 4 5% 46%	2161
	21st to end	Day	13% 11% 6% 15% 5% 4 4 3 4 6% 29%	3135
January	1st to 10th	Night	9% 10% 3 13% 5% 4 3 2 4 5% 42%	4108
	11th to 20th	Night	7% 9% 3 7% 5% 6% 5% 3 4 5% 47%	4120
	21st to end	Night	16% 11% 3 5% 3 3 3 3 4 5% 45%	4532
February	1st to 10th	Night	10% 10% 3 7% 4 4 3 3 5% 6% 44%	2470
	11th to 20th	Night	10% 8% 2 6% 4 3 4 4 5% 6% 48%	2299
	21st to end	Night	9% 6% 2 6% 4 4 4 3 5% 6% 52%	1884
March	1st to 10th	Night	11% 7% 2 4 2 3 3 3 4 6% 55%	3454
	11th to 20th	Night	9% 5% 2 4 3 3 4 3 5% 6% 56%	3480
	21st to end	Night	15% 7% 3 6% 4 3 3 3 5% 6% 46%	3817
April	1st to 10th	Night	10% 6% 2 5% 4 3 3 3 4 7% 53%	2085
	11th to 20th	Night	11% 7% 2 5% 3 3 3 4 6% 5% 50%	1794
	21st to end	Night	14% 6% 3 5% 3 3 4 3 5% 7% 46%	1710
May	1st to 10th	Night	16% 9% 2 4 3 3 3 3 4 7% 45%	2823
	11th to 20th	Night	15% 6% 2 5% 3 3 4 2 6% 8% 46%	2823
	21st to end	Night	11% 5% 1 4 3 3 3 3 5% 8% 54%	3090
June	1st to 10th	Night	6% 3 1 4 3 3 4 5% 6% 11% 54%	1710
	11th to 20th	Night	4 3 2 4 4 4 4 5% 7% 10% 53%	1710
	21st to end	Night	5% 3 1 5% 3 3 4 4 6% 7% 58%	1710
July	1st to 10th	Night	8% 5% 2 5% 4 4 4 3 6% 8% 51%	2850
	11th to 20th	Night	2 3 1 4 4 3 4 4 6% 10% 58%	2850
	21st to end	Night	7% 4 2 5% 5% 5% 5% 4 8% 10% 44%	3098
August	1st to 10th	Night	3 4 1 5% 4 4 5% 4 7% 9% 55%	2836
	11th to 20th	Night	9% 4 1 6% 4 4 4 4 6% 7% 51%	2798
	21st to end	Night	5% 2 1 3 3 3 3 3 4 8% 65%	3245
September	1st to 10th	Night	10% 3 1 4 3 3 2 3 5% 6% 60%	2051
	11th to 20th	Night	9% 4 2 4 3 3 4 3 6% 7% 56%	2090
	21st to end	Night	7% 4 2 4 3 3 3 3 3 7% 61%	2090
October	1st to 10th	Night	10% 4 2 5% 3 3 4 3 4 6% 55%	2178
	11th to 20th	Night	10% 4 2 4 3 3 2 2 4 5% 61%	2280
	21st to end	Night	13% 5% 2 3 3 3 3 2 4 5% 57%	2508
November	1st to 10th	Night	9% 4 1 4 2 3 3 2 4 5% 64%	2351
	11th to 20th	Night	8% 6% 1 4 3 2 3 2 5% 7% 59%	2470
	21st to end	Night	13% 6% 2 4 3 2 2 3 4 6% 57%	2470
December	1st to 10th	Night	8% 6% 3 6% 4 4 4 3 5% 6% 51%	2470
	11th to 20th	Night	10% 7% 3 5% 4 3 3 3 6% 5% 50%	3036
	21st to end	Night	17% 10% 5% 10% 4 4 3 2 4 5% 36%	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	48% 4 12% 21% 13% 1	2848
	11th to 20th	Day	47% 4 15% 20% 12% 3	2850
	21st to end	Day	47% 3 13% 21% 14% 1	3135
February	1st to 10th	Day	44% 5% 12% 24% 11% 4	1710
	11th to 20th	Day	39% 5% 12% 25% 14% 5%	1793
	21st to end	Day	36% 5% 11% 24% 19% 6%	1570
March	1st to 10th	Day	33% 3 8% 22% 28% 6%	3402
	11th to 20th	Day	27% 4 12% 29% 26% 2	3480
	21st to end	Day	42% 6% 13% 29% 8% 2	3814
April	1st to 10th	Day	35% 5% 11% 24% 21% 4	2094
	11th to 20th	Day	40% 6% 11% 23% 17% 2	2333
	21st to end	Day	44% 5% 11% 27% 12% 1	2470
May	1st to 10th	Day	48% 6% 9% 20% 13% 3	4120
	11th to 20th	Day	38% 6% 12% 25% 19% 1	4086
	21st to end	Day	39% 8% 13% 23% 15% 2	4489
June	1st to 10th	Day	26% 8% 16% 32% 15% 2	2470
	11th to 20th	Day	31% 6% 13% 28% 18% 4	2470
	21st to end	Day	25% 7% 15% 28% 21% 5%	2470
July	1st to 10th	Day	37% 6% 11% 23% 19% 4	4056
	11th to 20th	Day	26% 5% 13% 32% 19% 4	4051
	21st to end	Day	31% 6% 17% 26% 19% 1	4325
August	1st to 10th	Day	30% 5% 12% 25% 22% 6%	4090
	11th to 20th	Day	35% 4 15% 25% 17% 2	4080
	21st to end	Day	23% 4 16% 34% 18% 5%	4417
September	1st to 10th	Day	31% 5% 12% 23% 21% 8%	2125
	11th to 20th	Day	30% 5% 11% 28% 23% 3	2090
	21st to end	Day	30% 5% 9% 24% 27% 4	2090
October	1st to 10th	Day	30% 5% 12% 23% 26% 4	1981
	11th to 20th	Day	25% 3 9% 27% 28% 8%	1900
	21st to end	Day	33% 4 10% 23% 22% 7%	2090
November	1st to 10th	Day	26% 4 11% 30% 22% 7%	1758
	11th to 20th	Day	29% 4 9% 27% 26% 4	1710
	21st to end	Day	32% 4 9% 28% 23% 4	1710
December	1st to 10th	Day	33% 5% 11% 33% 17% 1	1710
	11th to 20th	Day	40% 4 10% 27% 16% 2	2159
	21st to end	Day	56% 5% 9% 19% 9% 2	3135
January	1st to 10th	Night	45% 4 10% 25% 14% 2	4108
	11th to 20th	Night	40% 4 13% 24% 17% 1	4120
	21st to end	Night	44% 3 13% 21% 17% 2	4532
February	1st to 10th	Night	41% 4 13% 23% 15% 4	2470
	11th to 20th	Night	36% 6% 11% 26% 18% 4	2300
	21st to end	Night	33% 6% 9% 22% 22% 8%	1884
March	1st to 10th	Night	31% 4 8% 25% 25% 7%	3454
	11th to 20th	Night	26% 6% 11% 23% 30% 3	3480
	21st to end	Night	39% 7% 15% 28% 10% 2	3817
April	1st to 10th	Night	31% 5% 12% 22% 24% 6%	2085
	11th to 20th	Night	34% 5% 12% 25% 21% 3	1794
	21st to end	Night	37% 6% 14% 23% 17% 3	1710
May	1st to 10th	Night	38% 7% 14% 22% 14% 5%	2850
	11th to 20th	Night	35% 6% 16% 28% 15%	2824
	21st to end	Night	27% 7% 17% 30% 17% 1	3099
June	1st to 10th	Night	23% 9% 20% 30% 15% 3	1710
	11th to 20th	Night	24% 7% 16% 31% 18% 3	1710
	21st to end	Night	23% 6% 14% 32% 20% 5%	1710
July	1st to 10th	Night	31% 5% 15% 23% 21% 6%	2805
	11th to 20th	Night	21% 4 14% 32% 25% 3	2796
	21st to end	Night	31% 7% 16% 30% 15% 1	2999
August	1st to 10th	Night	25% 4 17% 26% 19% 9%	2826
	11th to 20th	Night	32% 5% 16% 25% 20% 2	2825
	21st to end	Night	19% 4 14% 38% 18% 5%	3245
September	1st to 10th	Night	26% 4 11% 26% 23% 10%	2051
	11th to 20th	Night	28% 5% 11% 25% 26% 6%	2090
	21st to end	Night	25% 4 9% 24% 31% 7%	2090
October	1st to 10th	Night	29% 5% 10% 21% 28% 7%	2178
	11th to 20th	Night	26% 3 7% 28% 27% 9%	2280
	21st to end	Night	31% 4 9% 22% 28% 7%	2508
November	1st to 10th	Night	24% 4 9% 29% 25% 8%	2351
	11th to 20th	Night	26% 3 10% 29% 27% 5%	2470
	21st to end	Night	30% 4 11% 28% 22% 5%	2470
December	1st to 10th	Night	33% 5% 13% 27% 21% 2	2470
	11th to 20th	Night	35% 4 10% 30% 19% 3	3037
	21st to end	Night	51% 5% 9% 22% 10% 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	19% 17% 30% 25% 9% 1	270
	11th to 20th	Day	20% 16% 41% 20% 3	270
	21st to end	Day	13% 14% 44% 24% 5% 1	297
February	1st to 10th	Day	24% 19% 38% 16% 3	270
	11th to 20th	Day	16% 14% 48% 17% 5%	270
	21st to end	Day	15% 26% 43% 13% 2 1	225
March	1st to 10th	Day	20% 15% 44% 17% 3	270
	11th to 20th	Day	23% 14% 43% 16% 4	270
	21st to end	Day	24% 24% 36% 13% 3 1	297
April	1st to 10th	Day	20% 22% 37% 16% 4	274
	11th to 20th	Day	19% 14% 41% 21% 5% 1	531
	21st to end	Day	22% 19% 33% 18% 6% 2	650
May	1st to 10th	Day	19% 14% 38% 21% 8% 1	653
	11th to 20th	Day	19% 11% 28% 25% 14% 3	675
	21st to end	Day	19% 8% 30% 25% 15% 3	734
June	1st to 10th	Day	5% 5% 25% 37% 23% 5%	680
	11th to 20th	Day	8% 4 34% 37% 15% 3	680
	21st to end	Day	6% 8% 35% 37% 13% 1	680
July	1st to 10th	Day	11% 2 17% 34% 28% 8%	671
	11th to 20th	Day	4 4 18% 42% 27% 5%	668
	21st to end	Day	9% 2 16% 36% 31% 7%	739
August	1st to 10th	Day	7% 3 19% 38% 29% 3	676
	11th to 20th	Day	10% 2 18% 40% 25% 5%	665
	21st to end	Day	8% 2 17% 35% 30% 8%	686
September	1st to 10th	Day	10% 3 15% 38% 29% 5%	335
	11th to 20th	Day	6% 2 24% 40% 23% 4	300
	21st to end	Day	14% 6% 30% 30% 16% 4	300
October	1st to 10th	Day	12% 7% 34% 26% 16% 6%	300
	11th to 20th	Day	7% 18% 42% 25% 7% 1	300
	21st to end	Day	22% 14% 34% 22% 6% 2	330
November	1st to 10th	Day	12% 12% 36% 28% 11%	273
	11th to 20th	Day	17% 20% 32% 21% 8% 1	270
	21st to end	Day	21% 12% 36% 23% 8% 1	270
December	1st to 10th	Day	10% 15% 37% 29% 7% 3	270
	11th to 20th	Day	16% 15% 36% 25% 8%	270
	21st to end	Day	18% 21% 43% 16% 3	297
January	1st to 10th	Night	12% 12% 40% 30% 6%	950
	11th to 20th	Night	13% 15% 37% 28% 5% 1	950
	21st to end	Night	14% 13% 39% 31% 4	1045
February	1st to 10th	Night	16% 12% 42% 26% 3	950
	11th to 20th	Night	16% 13% 39% 28% 4	825
	21st to end	Night	14% 17% 41% 24% 4	628
March	1st to 10th	Night	14% 12% 42% 29% 4	594
	11th to 20th	Night	19% 12% 38% 25% 6% 1	570
	21st to end	Night	24% 13% 39% 20% 5%	627
April	1st to 10th	Night	15% 14% 42% 24% 5%	570
	11th to 20th	Night	17% 17% 36% 27% 4	563
	21st to end	Night	17% 13% 39% 24% 6% 1	570
May	1st to 10th	Night	19% 9% 35% 29% 6%	570
	11th to 20th	Night	16% 7% 30% 35% 11% 1	561
	21st to end	Night	13% 8% 30% 33% 14% 2	617
June	1st to 10th	Night	6% 4 30% 38% 22% 1	570
	11th to 20th	Night	5% 4 36% 39% 15%	570
	21st to end	Night	5% 4 36% 44% 11% 1	570
July	1st to 10th	Night	8% 2 18% 42% 28% 2	555
	11th to 20th	Night	3 2 20% 50% 22% 3	552
	21st to end	Night	9% 2 17% 40% 30% 2	624
August	1st to 10th	Night	5% 1 18% 48% 26% 1	567
	11th to 20th	Night	8% 2 16% 49% 24% 1	564
	21st to end	Night	7% 1 18% 42% 31% 2	627
September	1st to 10th	Night	11% 3 21% 43% 19% 2	570
	11th to 20th	Night	10% 2 26% 38% 21% 2	570
	21st to end	Night	8% 6% 29% 39% 18% 1	570
October	1st to 10th	Night	12% 6% 28% 34% 18% 1	658
	11th to 20th	Night	13% 8% 41% 30% 7%	760
	21st to end	Night	16% 11% 33% 29% 10%	836
November	1st to 10th	Night	11% 9% 35% 32% 13%	855
	11th to 20th	Night	12% 13% 39% 29% 7%	950
	21st to end	Night	16% 11% 33% 32% 7%	950
December	1st to 10th	Night	13% 10% 38% 31% 6% 1	950
	11th to 20th	Night	18% 11% 39% 28% 5%	950
	21st to end	Night	16% 15% 36% 28% 5%	1045

Page generated at 2024-10-30 12:19:25. Version ac07

Copyright © 2024 Attilla Danko.