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 2024-10-25.

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% 46%	100718
	Night	10% 7% 2 6% 4 4 4 3 5% 6% 50%	98120
Transparency	Day	38% 2 12% 27% 18% 3	100530
	Night	36% 2 11% 28% 19% 3	97979
Seeing	Day	15% 10% 31% 28% 14% 3	15641
	Night	14% 9% 33% 33% 11% 1	25459

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 11% 4 5% 4 3 5% 6% 37%	2847
	11th to 20th	Day	10% 10% 5% 9% 6% 7% 4 3 4 5% 38%	2850
	21st to end	Day	12% 16% 7% 7% 4 3 2 2 4 6% 37%	3135
February	1st to 10th	Day	13% 11% 3 7% 5% 5% 3 3 4 6% 40%	1710
	11th to 20th	Day	9% 10% 3 7% 4 4 4 4 6% 7% 42%	1711
	21st to end	Day	9% 10% 3 6% 4 4 4 3 6% 5% 46%	1586
March	1st to 10th	Day	12% 8% 2 6% 3 3 3 3 4 6% 50%	3436
	11th to 20th	Day	12% 6% 1 4 3 3 4 3 5% 6% 53%	3480
	21st to end	Day	14% 10% 6% 6% 4 4 4 3 5% 5% 37%	3814
April	1st to 10th	Day	13% 7% 2 6% 4 3 3 3 5% 7% 48%	2146
	11th to 20th	Day	13% 7% 3 7% 4 4 4 4 5% 6% 42%	2277
	21st to end	Day	18% 7% 3 7% 4 4 4 3 5% 6% 39%	2470
May	1st to 10th	Day	14% 10% 3 7% 4 4 4 3 5% 6% 40%	4082
	11th to 20th	Day	16% 7% 2 6% 4 4 4 4 5% 7% 40%	4082
	21st to end	Day	13% 7% 2 6% 4 4 4 4 6% 7% 44%	4477
June	1st to 10th	Day	5% 4 1 5% 4 4 4 5% 8% 11% 49%	2481
	11th to 20th	Day	7% 5% 2 5% 4 4 5% 4 5% 8% 49%	2594
	21st to end	Day	6% 4 2 5% 4 4 4 4 6% 9% 52%	2470
July	1st to 10th	Day	11% 6% 2 6% 4 4 5% 4 6% 8% 43%	4120
	11th to 20th	Day	5% 4 1 4 4 4 4 5% 7% 10% 52%	4120
	21st to end	Day	5% 4 2 5% 4 4 5% 4 8% 10% 48%	4465
August	1st to 10th	Day	6% 5% 2 4 3 4 5% 4 6% 8% 53%	4104
	11th to 20th	Day	12% 5% 2 6% 4 4 4 3 5% 8% 47%	4041
	21st to end	Day	5% 3 1 5% 4 4 4 4 6% 8% 55%	4354
September	1st to 10th	Day	11% 4 1 5% 4 3 3 2 5% 7% 54%	2214
	11th to 20th	Day	9% 5% 2 6% 5% 4 5% 4 5% 7% 49%	2090
	21st to end	Day	8% 5% 1 5% 3 3 5% 3 5% 7% 55%	2090
October	1st to 10th	Day	10% 5% 2 6% 2 3 3 3 5% 8% 52%	1933
	11th to 20th	Day	10% 6% 2 4 3 2 3 3 4 4 59%	1900
	21st to end	Day	15% 5% 2 5% 3 3 3 3 4 6% 51%	2026
November	1st to 10th	Day	8% 4 2 4 4 3 3 4 4 7% 56%	1787
	11th to 20th	Day	11% 6% 2 5% 3 3 3 3 4 4 56%	1710
	21st to end	Day	15% 7% 2 5% 3 2 3 3 5% 5% 51%	1566
December	1st to 10th	Day	9% 8% 2 5% 4 4 4 3 5% 8% 48%	1520
	11th to 20th	Day	11% 9% 4 7% 5% 4 4 3 4 6% 43%	1918
	21st to end	Day	14% 15% 7% 13% 5% 4 4 3 5% 5% 26%	3112
January	1st to 10th	Night	8% 9% 4 14% 5% 4 3 3 4 5% 40%	4108
	11th to 20th	Night	9% 10% 4 8% 5% 6% 6% 3 4 5% 41%	4120
	21st to end	Night	15% 12% 4 7% 4 3 4 3 4 5% 39%	4532
February	1st to 10th	Night	10% 12% 3 7% 5% 4 4 3 6% 6% 40%	2470
	11th to 20th	Night	10% 8% 3 8% 4 3 4 3 5% 6% 46%	2371
	21st to end	Night	11% 7% 2 6% 4 4 4 3 4 5% 50%	1866
March	1st to 10th	Night	12% 7% 2 5% 4 3 3 2 4 5% 54%	3419
	11th to 20th	Night	10% 6% 1 3 3 3 3 3 6% 8% 55%	3480
	21st to end	Night	16% 9% 3 6% 4 4 4 3 5% 6% 41%	3817
April	1st to 10th	Night	10% 6% 2 5% 4 4 3 2 5% 6% 52%	2033
	11th to 20th	Night	12% 7% 4 5% 4 3 4 3 5% 7% 46%	1848
	21st to end	Night	16% 6% 2 5% 4 5% 4 4 5% 6% 44%	1710
May	1st to 10th	Night	15% 8% 2 6% 4 4 4 3 5% 7% 42%	2823
	11th to 20th	Night	15% 6% 3 5% 4 4 4 3 5% 8% 44%	2823
	21st to end	Night	11% 5% 1 5% 3 3 4 3 6% 8% 53%	3090
June	1st to 10th	Night	5% 3 2 5% 3 4 3 3 6% 9% 57%	1677
	11th to 20th	Night	6% 3 2 4 3 4 5% 4 7% 8% 54%	1563
	21st to end	Night	4 3 1 4 3 3 4 3 6% 10% 60%	1710
July	1st to 10th	Night	10% 6% 2 6% 4 4 3 4 5% 6% 51%	2850
	11th to 20th	Night	2 2 1 4 3 4 4 4 6% 9% 60%	2850
	21st to end	Night	5% 3 2 6% 4 4 4 4 7% 11% 51%	3098
August	1st to 10th	Night	2 2 1 4 4 5% 4 4 7% 10% 58%	2836
	11th to 20th	Night	9% 5% 3 5% 4 4 4 3 5% 8% 50%	2798
	21st to end	Night	5% 3 2 5% 3 3 3 3 5% 8% 59%	3307
September	1st to 10th	Night	10% 4 1 5% 3 3 3 3 5% 6% 56%	1962
	11th to 20th	Night	8% 4 1 5% 3 3 5% 3 5% 7% 55%	2090
	21st to end	Night	6% 4 2 5% 4 3 3 3 4 6% 60%	2090
October	1st to 10th	Night	11% 4 2 5% 3 3 3 3 5% 7% 55%	2227
	11th to 20th	Night	12% 4 2 3 3 3 3 2 3 6% 59%	2280
	21st to end	Night	14% 6% 2 5% 3 2 3 2 3 5% 55%	2436
November	1st to 10th	Night	8% 4 2 4 3 3 3 3 3 5% 62%	2286
	11th to 20th	Night	9% 6% 1 4 3 4 3 3 4 6% 57%	2470
	21st to end	Night	13% 7% 2 3 3 3 3 3 4 6% 54%	2608
December	1st to 10th	Night	9% 8% 2 6% 4 5% 4 3 6% 6% 49%	2660
	11th to 20th	Night	10% 9% 3 6% 4 4 3 4 5% 6% 46%	3279
	21st to end	Night	18% 15% 5% 8% 4 3 3 2 4 4 33%	4533

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	50% 1 11% 25% 11% 1	2848
	11th to 20th	Day	51% 1 15% 20% 12% 1	2850
	21st to end	Day	50% 2 12% 21% 14% 1	3135
February	1st to 10th	Day	47% 3 12% 24% 11% 3	1710
	11th to 20th	Day	42% 2 13% 26% 14% 3	1720
	21st to end	Day	39% 2 9% 26% 19% 5%	1586
March	1st to 10th	Day	37% 2 9% 23% 24% 5%	3436
	11th to 20th	Day	33% 1 12% 29% 23% 2	3480
	21st to end	Day	49% 2 14% 27% 6% 1	3814
April	1st to 10th	Day	37% 3 12% 24% 21% 3	2146
	11th to 20th	Day	42% 3 11% 25% 18% 1	2277
	21st to end	Day	47% 3 10% 28% 12% 1	2470
May	1st to 10th	Day	46% 3 9% 25% 15% 2	4120
	11th to 20th	Day	44% 2 13% 24% 17%	4086
	21st to end	Day	40% 3 9% 32% 14% 2	4489
June	1st to 10th	Day	28% 4 17% 32% 18% 2	2481
	11th to 20th	Day	32% 4 13% 30% 19% 2	2594
	21st to end	Day	29% 3 14% 31% 18% 4	2470
July	1st to 10th	Day	39% 3 12% 23% 19% 4	4056
	11th to 20th	Day	27% 3 11% 35% 21% 3	4051
	21st to end	Day	30% 2 15% 33% 17% 3	4325
August	1st to 10th	Day	30% 3 12% 27% 24% 4	4090
	11th to 20th	Day	38% 2 15% 26% 17% 1	4080
	21st to end	Day	28% 2 16% 31% 18% 6%	4353
September	1st to 10th	Day	31% 3 11% 28% 20% 7%	2214
	11th to 20th	Day	35% 3 9% 27% 23% 3	2090
	21st to end	Day	30% 3 9% 30% 25% 3	2090
October	1st to 10th	Day	31% 2 11% 28% 24% 3	1933
	11th to 20th	Day	30% 2 6% 27% 29% 7%	1900
	21st to end	Day	36% 2 10% 26% 20% 6%	2026
November	1st to 10th	Day	29% 3 12% 30% 20% 6%	1787
	11th to 20th	Day	33% 1 9% 30% 23% 4	1710
	21st to end	Day	37% 2 9% 28% 23% 2	1566
December	1st to 10th	Day	34% 3 14% 33% 15% 1	1520
	11th to 20th	Day	44% 2 12% 27% 14% 1	1915
	21st to end	Day	62% 2 9% 18% 8% 1	3112
January	1st to 10th	Night	49% 2 12% 23% 13% 1	4108
	11th to 20th	Night	47% 2 11% 23% 16% 1	4120
	21st to end	Night	49% 2 12% 20% 14% 2	4532
February	1st to 10th	Night	45% 3 11% 24% 15% 3	2470
	11th to 20th	Night	40% 2 11% 27% 17% 3	2372
	21st to end	Night	37% 2 8% 24% 21% 7%	1866
March	1st to 10th	Night	36% 1 7% 28% 23% 4	3419
	11th to 20th	Night	29% 2 9% 28% 27% 5%	3480
	21st to end	Night	46% 2 16% 26% 8% 1	3817
April	1st to 10th	Night	34% 2 12% 25% 23% 5%	2033
	11th to 20th	Night	38% 3 8% 28% 19% 3	1848
	21st to end	Night	42% 3 10% 27% 15% 2	1710
May	1st to 10th	Night	42% 3 13% 24% 15% 3	2850
	11th to 20th	Night	41% 2 13% 27% 17% 1	2824
	21st to end	Night	31% 3 14% 32% 18% 1	3099
June	1st to 10th	Night	25% 3 19% 34% 16% 3	1677
	11th to 20th	Night	26% 4 14% 34% 18% 3	1563
	21st to end	Night	22% 2 14% 36% 22% 4	1710
July	1st to 10th	Night	36% 1 12% 24% 21% 5%	2805
	11th to 20th	Night	20% 3 12% 36% 26% 3	2796
	21st to end	Night	29% 2 16% 32% 19% 1	2999
August	1st to 10th	Night	22% 2 19% 28% 22% 7%	2826
	11th to 20th	Night	34% 2 15% 27% 20% 2	2825
	21st to end	Night	25% 2 13% 36% 19% 5%	3307
September	1st to 10th	Night	30% 2 9% 29% 21% 9%	1962
	11th to 20th	Night	29% 3 9% 28% 26% 5%	2090
	21st to end	Night	27% 2 8% 27% 32% 4	2090
October	1st to 10th	Night	31% 2 8% 25% 27% 6%	2227
	11th to 20th	Night	30% 1 5% 29% 26% 9%	2280
	21st to end	Night	35% 2 8% 24% 27% 4	2436
November	1st to 10th	Night	27% 2 11% 29% 25% 7%	2286
	11th to 20th	Night	30% 2 10% 30% 25% 4	2470
	21st to end	Night	34% 2 10% 30% 21% 4	2608
December	1st to 10th	Night	37% 3 12% 29% 18% 1	2660
	11th to 20th	Night	40% 2 9% 31% 16% 2	3281
	21st to end	Night	57% 2 7% 23% 9% 2	4533

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	22% 16% 35% 20% 7%	270
	11th to 20th	Day	24% 18% 40% 16% 3	270
	21st to end	Day	12% 17% 46% 21% 3	297
February	1st to 10th	Day	22% 21% 36% 18% 2	270
	11th to 20th	Day	18% 20% 45% 11% 6%	270
	21st to end	Day	16% 27% 44% 11% 4	225
March	1st to 10th	Day	17% 19% 43% 19% 2	270
	11th to 20th	Day	27% 11% 40% 17% 4	270
	21st to end	Day	29% 20% 39% 9% 3	297
April	1st to 10th	Day	24% 17% 34% 19% 5%	326
	11th to 20th	Day	20% 15% 37% 22% 5%	475
	21st to end	Day	25% 15% 33% 18% 8%	650
May	1st to 10th	Day	22% 12% 37% 21% 8% 1	653
	11th to 20th	Day	20% 9% 30% 27% 13% 2	675
	21st to end	Day	18% 10% 31% 27% 13% 2	734
June	1st to 10th	Day	6% 4 25% 37% 23% 6%	680
	11th to 20th	Day	8% 5% 32% 34% 17% 4	680
	21st to end	Day	9% 6% 35% 36% 12% 1	680
July	1st to 10th	Day	11% 2 18% 34% 26% 8%	671
	11th to 20th	Day	5% 2 22% 38% 27% 7%	668
	21st to end	Day	9% 2 20% 35% 28% 6%	739
August	1st to 10th	Day	9% 3 19% 38% 26% 5%	676
	11th to 20th	Day	10% 2 20% 43% 21% 4	665
	21st to end	Day	9% 2 17% 37% 28% 7%	648
September	1st to 10th	Day	13% 1 22% 38% 22% 4	424
	11th to 20th	Day	6% 3 27% 38% 22% 3	300
	21st to end	Day	16% 5% 30% 35% 12% 3	300
October	1st to 10th	Day	14% 9% 29% 27% 16% 5%	300
	11th to 20th	Day	11% 19% 42% 20% 8%	300
	21st to end	Day	22% 14% 36% 21% 7% 1	311
November	1st to 10th	Day	16% 13% 38% 26% 6% 2	270
	11th to 20th	Day	16% 17% 40% 20% 7%	270
	21st to end	Day	24% 11% 39% 17% 8%	270
December	1st to 10th	Day	11% 14% 41% 25% 6% 2	270
	11th to 20th	Day	20% 16% 37% 19% 7% 1	270
	21st to end	Day	22% 23% 35% 19% 1	297
January	1st to 10th	Night	12% 14% 37% 30% 7%	950
	11th to 20th	Night	16% 13% 37% 28% 5% 1	950
	21st to end	Night	15% 13% 38% 29% 4	1045
February	1st to 10th	Night	18% 14% 40% 26% 4	950
	11th to 20th	Night	15% 14% 38% 29% 3	897
	21st to end	Night	15% 15% 40% 24% 5%	610
March	1st to 10th	Night	14% 15% 40% 25% 6%	570
	11th to 20th	Night	20% 11% 36% 27% 5% 1	570
	21st to end	Night	26% 11% 37% 22% 4	627
April	1st to 10th	Night	15% 14% 40% 26% 6%	570
	11th to 20th	Night	17% 14% 40% 24% 5%	563
	21st to end	Night	21% 10% 38% 23% 6% 1	570
May	1st to 10th	Night	19% 8% 37% 29% 6%	570
	11th to 20th	Night	16% 6% 32% 34% 11% 1	561
	21st to end	Night	12% 7% 31% 34% 14% 2	617
June	1st to 10th	Night	7% 2 26% 41% 22% 1	570
	11th to 20th	Night	7% 3 32% 41% 16% 1	570
	21st to end	Night	7% 4 34% 42% 12% 1	570
July	1st to 10th	Night	10% 1 15% 47% 24% 2	555
	11th to 20th	Night	4 1 21% 51% 22% 3	552
	21st to end	Night	8% 1 17% 46% 26% 2	624
August	1st to 10th	Night	4 1 19% 47% 27% 2	567
	11th to 20th	Night	8% 1 15% 51% 24% 2	564
	21st to end	Night	7% 1 19% 42% 28% 2	627
September	1st to 10th	Night	13% 2 20% 44% 19% 2	570
	11th to 20th	Night	10% 1 26% 41% 20% 3	570
	21st to end	Night	7% 4 28% 42% 18% 1	570
October	1st to 10th	Night	14% 5% 29% 34% 17% 1	707
	11th to 20th	Night	15% 9% 41% 28% 8%	760
	21st to end	Night	20% 11% 34% 26% 8%	812
November	1st to 10th	Night	11% 10% 33% 35% 11% 1	806
	11th to 20th	Night	12% 14% 38% 29% 7%	950
	21st to end	Night	17% 11% 34% 30% 8%	950
December	1st to 10th	Night	15% 12% 36% 31% 6% 1	950
	11th to 20th	Night	18% 11% 38% 28% 5%	950
	21st to end	Night	20% 14% 36% 26% 4	1045

Page generated at 2024-10-22 19:21:00. Version ac07

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