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 2024-02-25.

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% 5% 3 4 4 5% 7% 45%	78393
	Night	11% 7% 3 5% 4 3 4 4 5% 6% 49%	80893
Transparency	Day	39% 3 12% 27% 17% 3	78116
	Night	37% 2 11% 27% 19% 3	80690
Seeing	Day	15% 10% 30% 28% 14% 3	14629
	Night	14% 9% 33% 33% 11% 1	24702

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% 6% 3 4 4 5% 6% 37%	2847
	11th to 20th	Day	10% 10% 5% 8% 7% 5% 5% 4 4 5% 38%	2850
	21st to end	Day	12% 15% 7% 7% 4 2 2 3 4 6% 37%	3135
February	1st to 10th	Day	13% 10% 4 6% 5% 4 4 3 4 6% 41%	1710
	11th to 20th	Day	9% 9% 5% 6% 5% 3 5% 4 6% 7% 43%	1711
	21st to end	Day	10% 10% 4 5% 5% 2 4 4 6% 6% 45%	1535
March	1st to 10th	Day	10% 7% 4 7% 5% 3 4 5% 5% 7% 44%	1980
	11th to 20th	Day	20% 9% 2 5% 4 2 3 4 4 6% 39%	1980
	21st to end	Day	18% 11% 4 6% 5% 3 4 5% 5% 6% 34%	2178
April	1st to 10th	Day	14% 6% 3 5% 4 2 3 4 5% 7% 48%	2033
	11th to 20th	Day	14% 7% 3 6% 5% 2 5% 4 5% 7% 41%	2155
	21st to end	Day	18% 7% 3 6% 5% 3 4 4 5% 6% 39%	2340
May	1st to 10th	Day	15% 10% 3 6% 5% 3 4 4 4 6% 39%	2340
	11th to 20th	Day	14% 7% 2 5% 6% 3 5% 5% 5% 8% 41%	2302
	21st to end	Day	14% 8% 4 6% 6% 4 5% 5% 7% 8% 35%	2531
June	1st to 10th	Day	5% 3 2 4 5% 3 5% 6% 7% 11% 49%	2350
	11th to 20th	Day	7% 4 3 5% 4 3 5% 5% 5% 8% 50%	2458
	21st to end	Day	6% 4 2 4 4 3 4 4 6% 9% 52%	2340
July	1st to 10th	Day	9% 4 2 4 4 3 5% 5% 7% 9% 46%	2340
	11th to 20th	Day	3 3 1 3 5% 3 5% 6% 8% 8% 54%	2340
	21st to end	Day	7% 5% 3 5% 5% 3 5% 4 7% 9% 47%	2546
August	1st to 10th	Day	7% 4 2 4 4 3 5% 6% 8% 10% 46%	2328
	11th to 20th	Day	8% 4 2 6% 5% 3 4 4 5% 8% 51%	2301
	21st to end	Day	7% 3 2 5% 5% 3 4 4 6% 7% 55%	2480
September	1st to 10th	Day	12% 4 1 4 5% 3 3 3 5% 7% 52%	2098
	11th to 20th	Day	9% 5% 2 5% 6% 3 4 5% 5% 7% 49%	1980
	21st to end	Day	8% 4 2 4 4 2 5% 4 5% 7% 55%	1980
October	1st to 10th	Day	11% 5% 2 5% 3 3 3 4 4 9% 51%	1832
	11th to 20th	Day	11% 6% 2 3 4 2 3 3 3 5% 58%	1800
	21st to end	Day	16% 5% 2 4 4 2 3 4 4 5% 51%	1980
November	1st to 10th	Day	8% 4 2 4 4 2 3 4 4 7% 57%	1787
	11th to 20th	Day	11% 5% 2 5% 4 2 3 4 4 5% 57%	1710
	21st to end	Day	15% 6% 3 4 4 2 2 4 4 5% 51%	1566
December	1st to 10th	Day	9% 7% 3 5% 5% 3 3 4 5% 8% 48%	1520
	11th to 20th	Day	11% 9% 4 6% 6% 3 4 4 4 6% 43%	1918
	21st to end	Day	14% 14% 7% 11% 7% 3 4 4 5% 5% 26%	3112
January	1st to 10th	Night	8% 9% 4 13% 6% 3 4 3 4 5% 40%	4108
	11th to 20th	Night	9% 9% 4 7% 5% 4 7% 4 4 5% 41%	4120
	21st to end	Night	15% 12% 5% 7% 5% 2 4 4 4 4 39%	4532
February	1st to 10th	Night	11% 11% 4 6% 5% 3 4 4 5% 6% 41%	2470
	11th to 20th	Night	10% 7% 3 7% 5% 2 5% 3 5% 7% 46%	2371
	21st to end	Night	11% 7% 2 5% 5% 3 5% 4 4 5% 50%	1813
March	1st to 10th	Night	10% 7% 3 5% 5% 2 4 4 5% 5% 50%	1980
	11th to 20th	Night	15% 8% 2 4 5% 2 4 4 5% 7% 44%	1980
	21st to end	Night	20% 9% 3 5% 5% 2 4 4 4 6% 37%	2178
April	1st to 10th	Night	10% 6% 2 4 4 3 3 3 5% 7% 53%	1926
	11th to 20th	Night	12% 6% 3 5% 5% 3 4 4 5% 7% 45%	1750
	21st to end	Night	16% 6% 2 4 4 3 5% 4 5% 6% 44%	1620
May	1st to 10th	Night	15% 7% 3 5% 5% 3 4 4 4 8% 41%	1620
	11th to 20th	Night	13% 5% 2 4 4 3 4 4 4 8% 49%	1593
	21st to end	Night	10% 6% 2 5% 4 2 5% 4 7% 9% 47%	1745
June	1st to 10th	Night	5% 2 2 4 3 3 4 4 6% 10% 58%	1589
	11th to 20th	Night	6% 3 2 4 3 3 4 5% 7% 9% 54%	1480
	21st to end	Night	5% 2 2 3 3 2 4 3 6% 9% 61%	1620
July	1st to 10th	Night	7% 4 1 3 4 2 4 5% 6% 8% 55%	1620
	11th to 20th	Night	2 2 1 3 3 3 3 5% 7% 10% 61%	1620
	21st to end	Night	6% 3 2 5% 4 3 4 4 6% 10% 51%	1772
August	1st to 10th	Night	4 2 1 4 5% 4 5% 5% 7% 9% 54%	1611
	11th to 20th	Night	6% 3 2 4 4 2 4 4 5% 8% 58%	1600
	21st to end	Night	6% 3 2 4 3 2 3 4 5% 6% 62%	1876
September	1st to 10th	Night	11% 4 2 4 4 2 4 4 5% 6% 55%	1858
	11th to 20th	Night	9% 4 1 4 4 2 4 4 5% 7% 55%	1980
	21st to end	Night	6% 4 2 4 4 2 4 4 4 6% 60%	1980
October	1st to 10th	Night	12% 4 2 5% 4 2 4 4 5% 6% 53%	2109
	11th to 20th	Night	13% 4 2 3 4 2 3 3 3 6% 58%	2160
	21st to end	Night	15% 6% 2 4 4 2 3 3 2 5% 54%	2376
November	1st to 10th	Night	8% 4 2 3 3 2 3 3 3 6% 62%	2286
	11th to 20th	Night	9% 5% 2 3 3 3 4 4 4 6% 57%	2470
	21st to end	Night	13% 6% 2 3 4 2 3 3 4 5% 54%	2608
December	1st to 10th	Night	9% 7% 3 5% 5% 3 5% 4 5% 6% 49%	2660
	11th to 20th	Night	10% 8% 3 6% 4 3 3 4 4 6% 47%	3279
	21st to end	Night	18% 15% 6% 8% 5% 2 4 3 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	40% 2 9% 27% 18% 4	1535
March	1st to 10th	Day	40% 3 11% 24% 17% 4	1980
	11th to 20th	Day	48% 2 9% 23% 16% 2	1980
	21st to end	Day	52% 4 14% 20% 9% 2	2178
April	1st to 10th	Day	38% 3 12% 25% 20% 3	2033
	11th to 20th	Day	43% 3 12% 25% 17% 1	2155
	21st to end	Day	47% 3 10% 27% 12% 1	2340
May	1st to 10th	Day	48% 4 12% 22% 14% 1	2340
	11th to 20th	Day	43% 3 14% 26% 13%	2306
	21st to end	Day	46% 5% 14% 24% 10% 2	2531
June	1st to 10th	Day	27% 4 17% 33% 17% 2	2350
	11th to 20th	Day	32% 4 12% 30% 19% 2	2458
	21st to end	Day	28% 3 13% 33% 18% 4	2340
July	1st to 10th	Day	34% 4 14% 28% 16% 4	2276
	11th to 20th	Day	25% 5% 15% 29% 21% 5%	2271
	21st to end	Day	31% 3 13% 34% 16% 2	2405
August	1st to 10th	Day	32% 5% 16% 29% 16% 2	2314
	11th to 20th	Day	31% 4 10% 34% 19% 2	2301
	21st to end	Day	29% 3 11% 27% 22% 7%	2480
September	1st to 10th	Day	33% 3 12% 28% 18% 7%	2098
	11th to 20th	Day	36% 3 10% 26% 22% 3	1980
	21st to end	Day	29% 3 9% 30% 26% 3	1980
October	1st to 10th	Day	33% 2 11% 29% 22% 3	1832
	11th to 20th	Day	32% 2 6% 26% 28% 6%	1800
	21st to end	Day	37% 2 10% 25% 20% 6%	1980
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 9% 25% 20% 7%	1813
March	1st to 10th	Night	37% 2 9% 27% 20% 5%	1980
	11th to 20th	Night	40% 3 12% 25% 16% 5%	1980
	21st to end	Night	49% 4 12% 20% 12% 3	2178
April	1st to 10th	Night	33% 2 12% 26% 23% 4	1926
	11th to 20th	Night	39% 3 8% 29% 19% 3	1750
	21st to end	Night	42% 3 10% 27% 16% 1	1620
May	1st to 10th	Night	43% 4 13% 22% 16% 2	1620
	11th to 20th	Night	36% 2 16% 26% 18% 1	1594
	21st to end	Night	34% 4 21% 26% 13% 2	1746
June	1st to 10th	Night	24% 3 20% 35% 16% 3	1589
	11th to 20th	Night	27% 4 14% 34% 18% 3	1480
	21st to end	Night	22% 3 13% 36% 22% 4	1620
July	1st to 10th	Night	29% 2 16% 31% 19% 4	1575
	11th to 20th	Night	17% 4 14% 35% 24% 5%	1566
	21st to end	Night	30% 3 11% 34% 21% 1	1673
August	1st to 10th	Night	24% 3 19% 36% 14% 3	1601
	11th to 20th	Night	26% 2 12% 34% 23% 3	1600
	21st to end	Night	23% 3 11% 31% 25% 7%	1876
September	1st to 10th	Night	31% 2 10% 29% 19% 8%	1858
	11th to 20th	Night	29% 3 9% 27% 26% 5%	1980
	21st to end	Night	26% 2 8% 27% 31% 4	1980
October	1st to 10th	Night	33% 3 9% 26% 24% 6%	2109
	11th to 20th	Night	31% 1 6% 29% 25% 8%	2160
	21st to end	Night	36% 2 8% 23% 26% 4	2376
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	17% 25% 42% 11% 4	210
March	1st to 10th	Day	15% 20% 44% 19% 2	240
	11th to 20th	Day	29% 10% 38% 18% 5%	240
	21st to end	Day	30% 19% 39% 9% 2	264
April	1st to 10th	Day	23% 17% 34% 20% 5%	293
	11th to 20th	Day	20% 15% 38% 22% 5%	433
	21st to end	Day	25% 15% 34% 18% 8% 1	600
May	1st to 10th	Day	22% 12% 37% 20% 8% 1	603
	11th to 20th	Day	21% 9% 31% 26% 12% 2	625
	21st to end	Day	18% 10% 30% 26% 13% 2	679
June	1st to 10th	Day	6% 4 23% 37% 23% 6%	630
	11th to 20th	Day	8% 4 31% 35% 17% 4	630
	21st to end	Day	9% 6% 34% 36% 13% 2	630
July	1st to 10th	Day	12% 1 16% 35% 28% 9%	621
	11th to 20th	Day	5% 2 20% 38% 28% 7%	618
	21st to end	Day	10% 1 20% 36% 28% 6%	684
August	1st to 10th	Day	9% 3 18% 38% 27% 5%	626
	11th to 20th	Day	9% 2 18% 44% 23% 5%	615
	21st to end	Day	9% 2 17% 37% 29% 7%	599
September	1st to 10th	Day	14% 1 23% 37% 21% 4	388
	11th to 20th	Day	6% 3 28% 38% 22% 3	270
	21st to end	Day	16% 5% 30% 34% 12% 2	270
October	1st to 10th	Day	16% 9% 29% 27% 15% 5%	270
	11th to 20th	Day	12% 19% 44% 20% 5%	270
	21st to end	Day	23% 14% 34% 20% 7% 1	297
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% 25% 6%	593
March	1st to 10th	Night	14% 15% 41% 24% 6%	540
	11th to 20th	Night	20% 12% 35% 27% 5% 1	540
	21st to end	Night	26% 10% 37% 23% 4	594
April	1st to 10th	Night	15% 13% 40% 26% 6%	540
	11th to 20th	Night	17% 14% 40% 24% 5%	533
	21st to end	Night	21% 10% 38% 23% 6% 1	540
May	1st to 10th	Night	19% 9% 37% 29% 6%	540
	11th to 20th	Night	16% 7% 34% 32% 11% 1	531
	21st to end	Night	13% 7% 30% 34% 15% 2	584
June	1st to 10th	Night	6% 2 26% 41% 23% 1	540
	11th to 20th	Night	7% 3 31% 41% 16% 1	540
	21st to end	Night	6% 4 34% 43% 12% 1	540
July	1st to 10th	Night	10% 2 13% 48% 25% 2	525
	11th to 20th	Night	4 1 20% 50% 22% 3	522
	21st to end	Night	8% 1 17% 47% 25% 2	591
August	1st to 10th	Night	4 1 19% 46% 28% 2	537
	11th to 20th	Night	7% 1 15% 51% 25% 2	534
	21st to end	Night	7% 1 18% 41% 29% 3	594
September	1st to 10th	Night	14% 2 21% 43% 19% 2	540
	11th to 20th	Night	10% 1 25% 41% 20% 3	540
	21st to end	Night	6% 4 28% 43% 17% 1	540
October	1st to 10th	Night	14% 5% 29% 33% 16% 1	669
	11th to 20th	Night	16% 9% 40% 27% 8%	720
	21st to end	Night	20% 11% 34% 26% 8%	792
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 2024-02-22 05:05:47. Version ac07

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