Topeka
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Topeka clear sky chart from 2005-11-06 to 2026-08-30.

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% 7% 3 6% 4 4 4 3 5% 7% 47%	143134
	Night	10% 7% 2 6% 4 4 4 3 5% 7% 50%	139379
Transparency	Day	38% 2 11% 27% 19% 4	146758
	Night	36% 2 10% 28% 20% 4	143822
Seeing	Day	15% 10% 31% 28% 13% 3	18215
	Night	14% 9% 33% 33% 10% 1	27958

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% 10% 3 9% 4 4 3 3 4 6% 43%	5289
	11th to 20th	Day	5% 7% 4 10% 6% 6% 4 4 5% 6% 42%	5310
	21st to end	Day	10% 13% 5% 6% 4 4 3 2 4 5% 43%	5812
February	1st to 10th	Day	12% 11% 4 7% 4 5% 3 3 4 6% 41%	1890
	11th to 20th	Day	10% 11% 3 7% 4 4 4 3 6% 7% 42%	1897
	21st to end	Day	8% 9% 3 5% 4 3 4 3 6% 5% 49%	1748
March	1st to 10th	Day	12% 7% 2 6% 3 3 3 2 4 5% 53%	5046
	11th to 20th	Day	10% 6% 1 4 3 3 3 3 4 6% 56%	5090
	21st to end	Day	12% 9% 5% 7% 4 4 5% 4 5% 7% 38%	5583
April	1st to 10th	Day	14% 7% 3 6% 3 2 3 3 5% 6% 47%	2372
	11th to 20th	Day	13% 7% 3 7% 4 4 5% 4 5% 6% 43%	2519
	21st to end	Day	18% 8% 3 7% 5% 4 4 3 5% 6% 38%	2730
May	1st to 10th	Day	15% 8% 3 6% 4 4 4 3 4 6% 45%	7617
	11th to 20th	Day	12% 5% 2 5% 4 4 4 4 5% 7% 49%	7627
	21st to end	Day	19% 7% 2 6% 4 4 4 4 6% 7% 37%	8392
June	1st to 10th	Day	6% 4 2 5% 4 4 4 5% 8% 11% 48%	2742
	11th to 20th	Day	7% 5% 2 5% 4 4 5% 4 5% 8% 49%	2866
	21st to end	Day	6% 4 2 5% 4 4 4 4 7% 9% 49%	2730
July	1st to 10th	Day	7% 5% 2 6% 4 4 5% 4 7% 9% 46%	7680
	11th to 20th	Day	6% 4 2 4 4 4 4 4 7% 9% 53%	7680
	21st to end	Day	9% 6% 2 6% 4 5% 5% 4 7% 9% 42%	8337
August	1st to 10th	Day	6% 5% 2 5% 4 4 5% 4 6% 8% 53%	4364
	11th to 20th	Day	12% 5% 2 6% 4 4 4 3 5% 8% 47%	4301
	21st to end	Day	6% 4 1 5% 4 4 4 4 6% 8% 54%	4606
September	1st to 10th	Day	11% 4 1 5% 4 3 3 3 5% 7% 53%	2330
	11th to 20th	Day	9% 5% 2 6% 5% 4 5% 4 5% 7% 49%	2200
	21st to end	Day	9% 5% 1 5% 3 3 5% 3 5% 6% 55%	2200
October	1st to 10th	Day	10% 5% 2 5% 2 4 4 3 5% 8% 53%	2035
	11th to 20th	Day	10% 6% 2 4 3 3 3 3 4 4 58%	2000
	21st to end	Day	17% 5% 2 5% 3 3 3 3 4 5% 51%	2200
November	1st to 10th	Day	8% 5% 2 4 4 3 3 3 4 7% 57%	1979
	11th to 20th	Day	10% 6% 2 5% 3 3 3 3 4 4 57%	1890
	21st to end	Day	15% 7% 3 5% 3 2 3 3 5% 5% 50%	1730
December	1st to 10th	Day	6% 5% 2 4 3 3 3 3 5% 7% 58%	2690
	11th to 20th	Day	9% 7% 3 6% 4 4 4 3 4 5% 51%	3088
	21st to end	Day	18% 14% 7% 11% 4 4 3 3 4 5% 28%	4564
January	1st to 10th	Night	11% 10% 4 12% 5% 4 3 3 4 5% 39%	7634
	11th to 20th	Night	6% 7% 3 7% 4 5% 5% 3 4 6% 50%	7680
	21st to end	Night	12% 10% 4 7% 4 4 4 3 4 5% 42%	8402
February	1st to 10th	Night	10% 12% 3 6% 5% 4 4 3 5% 6% 41%	2730
	11th to 20th	Night	10% 8% 3 8% 5% 4 4 3 5% 6% 45%	2627
	21st to end	Night	10% 7% 2 5% 4 4 4 4 4 5% 51%	2056
March	1st to 10th	Night	14% 7% 2 5% 3 3 2 2 3 4 55%	5029
	11th to 20th	Night	8% 5% 1 3 3 3 3 3 6% 8% 57%	5090
	21st to end	Night	13% 8% 3 6% 4 4 4 4 6% 7% 41%	5588
April	1st to 10th	Night	11% 6% 2 6% 4 4 3 2 5% 6% 50%	2247
	11th to 20th	Night	12% 6% 3 5% 4 3 4 4 5% 7% 46%	2045
	21st to end	Night	16% 7% 3 5% 4 5% 4 4 5% 6% 42%	1890
May	1st to 10th	Night	14% 6% 2 6% 4 3 3 3 4 7% 47%	5266
	11th to 20th	Night	13% 5% 2 4 3 3 3 3 5% 8% 51%	5265
	21st to end	Night	18% 6% 2 5% 3 3 4 3 5% 6% 45%	5793
June	1st to 10th	Night	5% 4 2 5% 3 4 3 3 6% 9% 55%	1854
	11th to 20th	Night	6% 3 1 5% 3 4 4 4 7% 8% 53%	1728
	21st to end	Night	5% 3 1 4 3 3 4 3 6% 9% 59%	1890
July	1st to 10th	Night	6% 4 2 5% 4 4 4 4 6% 8% 53%	5308
	11th to 20th	Night	4 3 2 5% 3 4 4 4 6% 8% 58%	5307
	21st to end	Night	8% 4 2 7% 4 4 5% 4 7% 10% 45%	5770
August	1st to 10th	Night	2 2 1 4 4 5% 4 4 7% 9% 58%	3016
	11th to 20th	Night	9% 5% 3 5% 4 4 4 3 6% 8% 50%	2978
	21st to end	Night	5% 3 2 5% 3 3 3 4 5% 8% 59%	3495
September	1st to 10th	Night	10% 4 2 6% 3 3 3 3 5% 6% 56%	2066
	11th to 20th	Night	8% 4 1 5% 4 3 5% 3 5% 7% 55%	2200
	21st to end	Night	6% 4 2 5% 4 3 4 3 4 6% 59%	2200
October	1st to 10th	Night	11% 4 2 5% 3 3 3 3 5% 6% 55%	2344
	11th to 20th	Night	12% 4 2 3 3 3 3 2 4 6% 58%	2400
	21st to end	Night	15% 7% 2 5% 3 3 3 2 3 5% 53%	2640
November	1st to 10th	Night	8% 5% 2 4 3 3 3 3 4 5% 61%	2534
	11th to 20th	Night	9% 6% 1 4 3 4 4 3 4 6% 57%	2730
	21st to end	Night	13% 7% 2 4 3 3 3 2 4 6% 53%	2884
December	1st to 10th	Night	6% 6% 2 5% 3 3 3 3 5% 6% 58%	4720
	11th to 20th	Night	10% 7% 3 6% 4 4 4 4 5% 6% 48%	5339
	21st to end	Night	18% 13% 5% 8% 4 3 4 3 4 4 34%	6634

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	46% 2 9% 29% 13% 1	5290
	11th to 20th	Day	44% 1 12% 22% 17% 4	5310
	21st to end	Day	46% 1 12% 23% 16% 2	5812
February	1st to 10th	Day	46% 2 12% 25% 11% 3	1890
	11th to 20th	Day	43% 2 12% 26% 14% 3	1906
	21st to end	Day	37% 2 9% 27% 21% 4	1748
March	1st to 10th	Day	36% 1 8% 21% 24% 10%	5046
	11th to 20th	Day	31% 1 8% 22% 28% 9%	5090
	21st to end	Day	47% 2 13% 30% 7% 1	5585
April	1st to 10th	Day	38% 2 12% 24% 20% 3	2372
	11th to 20th	Day	42% 3 11% 24% 19% 2	2519
	21st to end	Day	48% 2 10% 27% 11% 1	2730
May	1st to 10th	Day	43% 2 7% 27% 20% 1	7655
	11th to 20th	Day	36% 1 10% 25% 25% 4	7631
	21st to end	Day	48% 2 8% 26% 15% 1	8405
June	1st to 10th	Day	30% 4 17% 30% 18% 2	2742
	11th to 20th	Day	32% 4 13% 30% 19% 2	2866
	21st to end	Day	31% 3 14% 30% 17% 4	2730
July	1st to 10th	Day	36% 2 11% 29% 21% 2	7616
	11th to 20th	Day	29% 2 12% 29% 20% 7%	7611
	21st to end	Day	39% 2 12% 34% 12% 2	8155
August	1st to 10th	Day	30% 3 12% 27% 23% 4	4350
	11th to 20th	Day	37% 2 15% 27% 17% 1	4340
	21st to end	Day	29% 2 16% 30% 17% 6%	4605
September	1st to 10th	Day	32% 2 12% 28% 20% 7%	2330
	11th to 20th	Day	36% 3 10% 27% 22% 3	2200
	21st to end	Day	30% 3 9% 30% 25% 3	2200
October	1st to 10th	Day	21% 1 6% 21% 42% 8%	3308
	11th to 20th	Day	20% 1 4 30% 34% 11%	3240
	21st to end	Day	32% 1 9% 28% 26% 4	3538
November	1st to 10th	Day	29% 3 12% 31% 20% 6%	1979
	11th to 20th	Day	33% 1 9% 30% 23% 4	1890
	21st to end	Day	38% 2 9% 28% 21% 2	1730
December	1st to 10th	Day	28% 2 11% 40% 18% 1	2690
	11th to 20th	Day	38% 1 11% 35% 14% 1	3085
	21st to end	Day	61% 1 9% 20% 7% 1	4564
January	1st to 10th	Night	51% 1 11% 24% 12% 1	7635
	11th to 20th	Night	37% 1 9% 28% 22% 3	7680
	21st to end	Night	47% 1 11% 19% 18% 5%	8402
February	1st to 10th	Night	45% 2 11% 24% 15% 3	2730
	11th to 20th	Night	42% 2 11% 27% 16% 3	2628
	21st to end	Night	36% 2 8% 24% 23% 7%	2056
March	1st to 10th	Night	36% 1 5% 26% 27% 5%	5029
	11th to 20th	Night	27% 1 7% 22% 34% 10%	5090
	21st to end	Night	44% 2 14% 29% 10% 3	5588
April	1st to 10th	Night	36% 1 11% 24% 23% 5%	2247
	11th to 20th	Night	38% 3 8% 27% 20% 4	2045
	21st to end	Night	43% 3 11% 27% 15% 2	1890
May	1st to 10th	Night	39% 2 9% 28% 19% 3	5293
	11th to 20th	Night	35% 1 11% 26% 22% 6%	5266
	21st to end	Night	42% 2 11% 27% 17% 1	5805
June	1st to 10th	Night	27% 3 20% 32% 16% 3	1854
	11th to 20th	Night	27% 4 14% 33% 18% 4	1728
	21st to end	Night	23% 2 14% 35% 21% 4	1890
July	1st to 10th	Night	31% 1 14% 28% 24% 3	5265
	11th to 20th	Night	25% 2 14% 30% 22% 7%	5256
	21st to end	Night	36% 1 13% 36% 13% 1	5641
August	1st to 10th	Night	22% 2 19% 28% 22% 7%	3006
	11th to 20th	Night	34% 2 15% 29% 20% 2	3005
	21st to end	Night	25% 2 14% 36% 19% 5%	3495
September	1st to 10th	Night	31% 2 10% 28% 21% 8%	2066
	11th to 20th	Night	29% 3 10% 28% 25% 5%	2200
	21st to end	Night	27% 2 8% 26% 32% 4	2200
October	1st to 10th	Night	21% 1 5% 18% 46% 7%	3838
	11th to 20th	Night	22% 1 4 30% 30% 13%	3899
	21st to end	Night	33% 1 6% 29% 27% 3	4252
November	1st to 10th	Night	28% 2 11% 29% 24% 6%	2534
	11th to 20th	Night	29% 2 10% 30% 24% 5%	2730
	21st to end	Night	35% 2 10% 30% 20% 3	2884
December	1st to 10th	Night	29% 2 13% 35% 20% 1	4720
	11th to 20th	Night	38% 1 11% 31% 17% 3	5341
	21st to end	Night	55% 2 8% 25% 8% 1	6634

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	21% 16% 36% 22% 6%	330
	11th to 20th	Day	21% 20% 41% 15% 2	330
	21st to end	Day	12% 16% 46% 23% 3	363
February	1st to 10th	Day	20% 21% 38% 19% 2	330
	11th to 20th	Day	19% 21% 42% 12% 6%	330
	21st to end	Day	14% 25% 44% 14% 3	273
March	1st to 10th	Day	20% 18% 41% 18% 2	330
	11th to 20th	Day	27% 12% 37% 19% 5%	330
	21st to end	Day	28% 21% 40% 9% 3	363
April	1st to 10th	Day	26% 18% 33% 18% 4	392
	11th to 20th	Day	21% 16% 40% 19% 4	557
	21st to end	Day	26% 15% 35% 17% 7%	750
May	1st to 10th	Day	21% 12% 35% 22% 8% 1	753
	11th to 20th	Day	19% 11% 31% 26% 12% 2	775
	21st to end	Day	19% 9% 31% 27% 12% 2	844
June	1st to 10th	Day	7% 4 26% 36% 21% 5%	780
	11th to 20th	Day	9% 5% 33% 33% 16% 4	780
	21st to end	Day	10% 6% 36% 35% 12% 2	780
July	1st to 10th	Day	10% 2 20% 34% 26% 8%	771
	11th to 20th	Day	5% 2 21% 37% 27% 8%	768
	21st to end	Day	10% 2 20% 36% 25% 6%	849
August	1st to 10th	Day	9% 2 22% 37% 24% 5%	776
	11th to 20th	Day	10% 2 19% 44% 21% 4	765
	21st to end	Day	10% 2 16% 38% 27% 7%	740
September	1st to 10th	Day	13% 1 22% 38% 22% 3	460
	11th to 20th	Day	6% 3 27% 38% 22% 3	330
	21st to end	Day	16% 4 28% 34% 13% 4	330
October	1st to 10th	Day	14% 8% 30% 28% 15% 5%	330
	11th to 20th	Day	11% 18% 42% 21% 8%	330
	21st to end	Day	25% 14% 35% 20% 6% 1	363
November	1st to 10th	Day	16% 15% 40% 23% 5% 2	330
	11th to 20th	Day	15% 16% 41% 21% 7%	330
	21st to end	Day	24% 13% 38% 17% 8%	330
December	1st to 10th	Day	12% 16% 41% 25% 5% 2	330
	11th to 20th	Day	18% 17% 39% 18% 7% 1	330
	21st to end	Day	22% 20% 34% 22% 2	363
January	1st to 10th	Night	12% 14% 38% 30% 6%	1050
	11th to 20th	Night	15% 13% 39% 27% 5% 1	1050
	21st to end	Night	15% 13% 39% 29% 4	1155
February	1st to 10th	Night	17% 13% 40% 26% 4	1050
	11th to 20th	Night	16% 15% 38% 27% 3	993
	21st to end	Night	14% 14% 42% 25% 5%	672
March	1st to 10th	Night	15% 14% 40% 25% 5%	630
	11th to 20th	Night	20% 12% 38% 26% 5% 1	630
	21st to end	Night	25% 11% 39% 21% 4	693
April	1st to 10th	Night	16% 14% 40% 25% 6%	630
	11th to 20th	Night	17% 15% 40% 23% 4	623
	21st to end	Night	22% 10% 39% 23% 6% 1	630
May	1st to 10th	Night	19% 8% 37% 30% 6%	630
	11th to 20th	Night	16% 7% 33% 32% 11%	621
	21st to end	Night	14% 6% 31% 34% 13% 1	683
June	1st to 10th	Night	8% 2 27% 41% 21% 1	630
	11th to 20th	Night	8% 4 32% 40% 15% 1	630
	21st to end	Night	7% 4 35% 42% 11% 1	630
July	1st to 10th	Night	9% 1 16% 47% 24% 2	615
	11th to 20th	Night	4 1 20% 49% 23% 3	612
	21st to end	Night	9% 1 17% 47% 24% 2	690
August	1st to 10th	Night	4 1 21% 46% 25% 2	627
	11th to 20th	Night	7% 1 15% 52% 23% 2	624
	21st to end	Night	7% 1 18% 44% 28% 2	687
September	1st to 10th	Night	13% 2 20% 43% 19% 2	600
	11th to 20th	Night	10% 1 26% 41% 20% 3	600
	21st to end	Night	7% 4 27% 42% 20% 1	600
October	1st to 10th	Night	13% 5% 30% 34% 17% 1	744
	11th to 20th	Night	15% 9% 41% 28% 8%	800
	21st to end	Night	21% 11% 35% 25% 8%	880
November	1st to 10th	Night	12% 10% 34% 34% 10% 1	894
	11th to 20th	Night	12% 14% 38% 29% 7%	1050
	21st to end	Night	18% 11% 34% 30% 8%	1050
December	1st to 10th	Night	14% 12% 36% 31% 6%	1050
	11th to 20th	Night	18% 11% 39% 27% 5%	1050
	21st to end	Night	20% 13% 35% 28% 4	1155

Page generated at 2026-08-27 03:07:11. Version ac07

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