The Kiski School Astronomy Club
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the The Kiski School Astronomy Club clear sky chart from 2005-11-06 to 2024-04-10.

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	17% 11% 4 7% 6% 3 5% 5% 5% 7% 30%	83227
	Night	18% 12% 5% 7% 6% 3 4 4 5% 6% 31%	85556
Transparency	Day	54% 7% 11% 18% 9% 1	82943
	Night	54% 6% 11% 19% 9% 1	85359
Seeing	Day	26% 13% 25% 20% 11% 4	13902
	Night	24% 11% 24% 27% 12% 1	23692

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	20% 20% 10% 11% 6% 2 3 2 3 4 17%	2744
	11th to 20th	Day	13% 21% 10% 15% 12% 3 3 3 2 3 16%	2840
	21st to end	Day	25% 21% 6% 12% 8% 4 4 2 2 4 12%	3124
February	1st to 10th	Day	20% 16% 6% 11% 8% 4 4 4 3 5% 20%	1710
	11th to 20th	Day	16% 15% 8% 12% 6% 4 4 4 4 5% 21%	1663
	21st to end	Day	22% 15% 5% 11% 6% 2 4 4 4 5% 24%	1567
March	1st to 10th	Day	20% 12% 5% 7% 6% 3 4 3 5% 6% 30%	3435
	11th to 20th	Day	15% 11% 6% 8% 6% 4 5% 5% 4 5% 31%	3480
	21st to end	Day	18% 10% 3 8% 6% 3 4 5% 5% 6% 32%	3815
April	1st to 10th	Day	15% 12% 4 7% 6% 3 5% 5% 6% 6% 30%	2208
	11th to 20th	Day	17% 10% 4 7% 5% 4 5% 4 5% 6% 33%	2134
	21st to end	Day	22% 9% 3 6% 5% 3 4 4 4 7% 33%	2329
May	1st to 10th	Day	20% 9% 3 7% 5% 3 5% 6% 5% 8% 28%	2340
	11th to 20th	Day	21% 9% 3 6% 7% 4 5% 5% 5% 7% 29%	2301
	21st to end	Day	14% 6% 3 5% 5% 4 6% 5% 6% 9% 37%	2725
June	1st to 10th	Day	15% 6% 3 6% 6% 4 7% 5% 7% 8% 33%	2520
	11th to 20th	Day	14% 7% 2 6% 6% 4 6% 6% 7% 9% 33%	2520
	21st to end	Day	14% 6% 3 6% 6% 4 6% 5% 5% 10% 36%	2520
July	1st to 10th	Day	11% 6% 3 6% 6% 4 5% 5% 6% 8% 38%	2508
	11th to 20th	Day	12% 6% 3 5% 5% 3 5% 6% 8% 10% 36%	2340
	21st to end	Day	13% 6% 3 7% 6% 4 7% 6% 6% 8% 33%	2547
August	1st to 10th	Day	11% 6% 3 6% 7% 4 7% 7% 8% 9% 33%	2327
	11th to 20th	Day	14% 7% 3 6% 6% 4 6% 6% 7% 9% 34%	2303
	21st to end	Day	13% 6% 2 5% 6% 4 5% 5% 7% 9% 37%	2426
September	1st to 10th	Day	17% 7% 2 5% 5% 2 4 4 6% 7% 41%	2160
	11th to 20th	Day	13% 6% 2 4 6% 3 4 5% 5% 7% 44%	2030
	21st to end	Day	19% 9% 3 6% 5% 3 4 4 5% 7% 37%	1954
October	1st to 10th	Day	17% 6% 3 5% 5% 3 5% 5% 6% 9% 37%	1800
	11th to 20th	Day	20% 9% 3 7% 4 3 5% 4 4 7% 34%	1800
	21st to end	Day	24% 10% 3 6% 5% 3 3 4 5% 6% 31%	1980
November	1st to 10th	Day	12% 9% 3 6% 6% 3 4 4 4 7% 41%	1819
	11th to 20th	Day	18% 13% 4 6% 5% 3 4 4 5% 6% 31%	1536
	21st to end	Day	19% 17% 5% 7% 5% 3 5% 4 4 5% 25%	1520
December	1st to 10th	Day	21% 18% 8% 10% 7% 3 4 4 3 4 17%	1520
	11th to 20th	Day	20% 18% 9% 9% 6% 2 3 4 4 6% 20%	1910
	21st to end	Day	24% 23% 8% 9% 5% 3 3 3 4 4 15%	2772
January	1st to 10th	Night	17% 21% 9% 11% 5% 4 3 4 4 5% 18%	4196
	11th to 20th	Night	16% 20% 8% 12% 8% 4 5% 3 4 4 15%	4120
	21st to end	Night	28% 17% 7% 9% 8% 3 3 3 2 3 16%	4532
February	1st to 10th	Night	19% 14% 7% 10% 6% 3 4 4 4 5% 24%	2470
	11th to 20th	Night	18% 14% 6% 11% 7% 3 5% 3 4 5% 24%	2403
	21st to end	Night	21% 12% 5% 11% 5% 3 4 4 4 5% 26%	1884
March	1st to 10th	Night	23% 11% 4 6% 5% 2 3 4 4 5% 32%	3418
	11th to 20th	Night	17% 14% 5% 6% 5% 2 3 3 4 6% 33%	3480
	21st to end	Night	17% 9% 4 7% 6% 3 3 4 4 5% 38%	3817
April	1st to 10th	Night	19% 12% 4 6% 4 3 4 4 4 5% 35%	1962
	11th to 20th	Night	16% 8% 3 6% 5% 2 4 4 6% 7% 38%	1775
	21st to end	Night	16% 8% 3 7% 6% 3 4 4 5% 7% 35%	1647
May	1st to 10th	Night	19% 9% 3 7% 6% 2 5% 5% 6% 6% 33%	1620
	11th to 20th	Night	19% 7% 3 7% 5% 3 5% 4 6% 7% 35%	1590
	21st to end	Night	10% 6% 3 5% 5% 3 4 5% 6% 11% 44%	1550
June	1st to 10th	Night	12% 5% 3 4 6% 4 4 6% 6% 9% 42%	1440
	11th to 20th	Night	11% 7% 3 5% 6% 4 4 6% 6% 9% 39%	1440
	21st to end	Night	12% 6% 2 4 4 4 5% 5% 7% 11% 41%	1440
July	1st to 10th	Night	10% 5% 3 6% 6% 4 5% 6% 4 9% 44%	1448
	11th to 20th	Night	9% 5% 2 4 6% 3 4 5% 7% 10% 45%	1620
	21st to end	Night	11% 4 3 6% 5% 4 5% 6% 7% 10% 38%	1771
August	1st to 10th	Night	8% 5% 2 6% 5% 3 6% 6% 6% 9% 43%	1611
	11th to 20th	Night	11% 5% 3 5% 7% 3 4 5% 6% 9% 42%	1598
	21st to end	Night	11% 6% 2 5% 4 3 5% 6% 6% 9% 43%	1911
September	1st to 10th	Night	13% 5% 2 4 4 3 4 5% 6% 7% 46%	1800
	11th to 20th	Night	10% 4 2 4 4 2 4 4 5% 9% 52%	1927
	21st to end	Night	17% 7% 2 6% 4 3 4 4 5% 6% 42%	2006
October	1st to 10th	Night	15% 7% 3 5% 6% 3 4 5% 5% 6% 42%	2160
	11th to 20th	Night	18% 7% 3 6% 5% 3 4 4 5% 7% 37%	2160
	21st to end	Night	25% 9% 3 5% 4 2 4 3 5% 6% 34%	2376
November	1st to 10th	Night	13% 10% 3 5% 4 2 4 4 5% 6% 43%	2254
	11th to 20th	Night	19% 12% 3 6% 5% 4 5% 4 5% 6% 31%	2641
	21st to end	Night	19% 14% 5% 6% 5% 2 4 4 5% 6% 30%	2660
December	1st to 10th	Night	21% 17% 9% 9% 6% 3 4 4 4 5% 19%	2660
	11th to 20th	Night	20% 17% 6% 10% 6% 3 4 4 4 5% 22%	3285
	21st to end	Night	24% 19% 6% 9% 6% 3 5% 4 4 5% 14%	4884

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	72% 4 9% 11% 4	2745
	11th to 20th	Day	75% 3 7% 11% 3 1	2840
	21st to end	Day	79% 3 7% 8% 2	3124
February	1st to 10th	Day	70% 4 8% 13% 6% 1	1710
	11th to 20th	Day	65% 5% 10% 13% 6%	1672
	21st to end	Day	63% 5% 11% 14% 6% 1	1567
March	1st to 10th	Day	54% 6% 11% 23% 6%	3435
	11th to 20th	Day	55% 6% 12% 20% 6% 1	3480
	21st to end	Day	51% 6% 11% 20% 10% 1	3815
April	1st to 10th	Day	53% 6% 10% 18% 10% 2	2208
	11th to 20th	Day	51% 6% 10% 16% 15% 2	2134
	21st to end	Day	53% 6% 11% 19% 10% 2	2329
May	1st to 10th	Day	52% 8% 12% 17% 9% 2	2340
	11th to 20th	Day	54% 7% 11% 15% 11% 2	2305
	21st to end	Day	41% 10% 18% 21% 8% 2	2725
June	1st to 10th	Day	46% 11% 12% 20% 11% 1	2520
	11th to 20th	Day	45% 10% 14% 20% 11% 1	2520
	21st to end	Day	44% 8% 11% 25% 10% 1	2520
July	1st to 10th	Day	43% 10% 11% 20% 13% 3	2438
	11th to 20th	Day	40% 9% 15% 21% 14% 1	2271
	21st to end	Day	45% 9% 11% 21% 13% 1	2405
August	1st to 10th	Day	43% 11% 14% 24% 8%	2314
	11th to 20th	Day	43% 10% 15% 21% 10% 1	2303
	21st to end	Day	41% 9% 12% 23% 12% 3	2426
September	1st to 10th	Day	42% 8% 11% 20% 16% 4	2160
	11th to 20th	Day	38% 7% 13% 26% 14% 1	2030
	21st to end	Day	46% 6% 12% 22% 13% 1	1954
October	1st to 10th	Day	43% 7% 14% 20% 15% 1	1800
	11th to 20th	Day	50% 7% 12% 22% 9%	1800
	21st to end	Day	55% 6% 11% 17% 11% 1	1980
November	1st to 10th	Day	44% 6% 12% 19% 16% 3	1819
	11th to 20th	Day	54% 6% 11% 18% 10% 2	1536
	21st to end	Day	62% 5% 11% 16% 6% 1	1520
December	1st to 10th	Day	72% 5% 9% 11% 3	1520
	11th to 20th	Day	67% 4 11% 15% 3	1906
	21st to end	Day	75% 4 8% 10% 3	2772
January	1st to 10th	Night	70% 5% 9% 12% 3	4196
	11th to 20th	Night	73% 5% 10% 10% 1	4120
	21st to end	Night	75% 4 6% 12% 3	4532
February	1st to 10th	Night	64% 5% 9% 16% 6%	2470
	11th to 20th	Night	65% 4 10% 14% 7%	2405
	21st to end	Night	62% 5% 10% 14% 9% 1	1884
March	1st to 10th	Night	54% 5% 10% 23% 7%	3418
	11th to 20th	Night	53% 6% 12% 23% 5% 1	3480
	21st to end	Night	47% 5% 11% 22% 13% 2	3817
April	1st to 10th	Night	52% 6% 10% 18% 13% 1	1962
	11th to 20th	Night	46% 6% 11% 19% 15% 3	1775
	21st to end	Night	48% 6% 11% 22% 10% 3	1647
May	1st to 10th	Night	50% 7% 10% 17% 12% 3	1620
	11th to 20th	Night	50% 6% 11% 16% 14% 2	1591
	21st to end	Night	34% 9% 16% 27% 12% 2	1551
June	1st to 10th	Night	39% 8% 13% 25% 14% 1	1440
	11th to 20th	Night	40% 9% 14% 23% 12% 1	1440
	21st to end	Night	37% 9% 13% 24% 16% 1	1440
July	1st to 10th	Night	38% 10% 12% 21% 14% 4	1408
	11th to 20th	Night	32% 8% 15% 25% 18% 2	1566
	21st to end	Night	39% 9% 15% 21% 14% 3	1672
August	1st to 10th	Night	35% 9% 16% 25% 14%	1600
	11th to 20th	Night	38% 7% 15% 24% 14% 2	1598
	21st to end	Night	35% 8% 14% 25% 13% 4	1911
September	1st to 10th	Night	35% 8% 12% 24% 17% 4	1800
	11th to 20th	Night	29% 7% 14% 27% 21% 1	1927
	21st to end	Night	43% 6% 12% 22% 16% 1	2006
October	1st to 10th	Night	41% 7% 13% 23% 14% 2	2160
	11th to 20th	Night	47% 5% 11% 24% 12% 1	2160
	21st to end	Night	52% 5% 11% 20% 11% 2	2376
November	1st to 10th	Night	42% 6% 11% 20% 17% 4	2254
	11th to 20th	Night	55% 4 10% 18% 11% 2	2641
	21st to end	Night	56% 6% 11% 19% 7% 1	2660
December	1st to 10th	Night	69% 5% 11% 10% 4	2660
	11th to 20th	Night	66% 4 11% 15% 3	3288
	21st to end	Night	72% 7% 10% 10% 2	4884

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	33% 25% 23% 11% 5% 2	245
	11th to 20th	Day	40% 25% 27% 6% 1 1	270
	21st to end	Day	38% 22% 28% 8% 3 1	297
February	1st to 10th	Day	36% 21% 36% 6% 2	270
	11th to 20th	Day	40% 26% 27% 6% 1	270
	21st to end	Day	42% 23% 27% 7% 1	286
March	1st to 10th	Day	31% 22% 28% 15% 4	460
	11th to 20th	Day	37% 17% 29% 12% 5% 1	460
	21st to end	Day	33% 19% 25% 17% 5% 1	506
April	1st to 10th	Day	29% 21% 25% 18% 5% 2	457
	11th to 20th	Day	26% 20% 26% 16% 9% 4	412
	21st to end	Day	33% 15% 26% 18% 5% 2	420
May	1st to 10th	Day	32% 14% 25% 17% 9% 3	423
	11th to 20th	Day	23% 12% 31% 19% 11% 4	447
	21st to end	Day	20% 6% 25% 27% 15% 7%	485
June	1st to 10th	Day	18% 10% 30% 26% 13% 4	450
	11th to 20th	Day	22% 10% 24% 24% 16% 4	450
	21st to end	Day	18% 6% 28% 32% 14% 2	450
July	1st to 10th	Day	17% 4 17% 29% 21% 11%	445
	11th to 20th	Day	14% 5% 25% 31% 17% 7%	444
	21st to end	Day	16% 4 25% 30% 18% 7%	488
August	1st to 10th	Day	13% 5% 19% 32% 21% 10%	446
	11th to 20th	Day	19% 3 18% 29% 19% 12%	439
	21st to end	Day	15% 4 24% 25% 20% 11%	495
September	1st to 10th	Day	22% 6% 19% 26% 17% 11%	450
	11th to 20th	Day	17% 2 17% 33% 19% 12%	450
	21st to end	Day	25% 10% 21% 24% 14% 6%	450
October	1st to 10th	Day	21% 8% 26% 21% 20% 4	450
	11th to 20th	Day	26% 14% 27% 22% 10% 1	450
	21st to end	Day	35% 11% 30% 16% 8% 1	495
November	1st to 10th	Day	20% 14% 28% 23% 11% 4	417
	11th to 20th	Day	34% 16% 29% 13% 6% 2	187
	21st to end	Day	28% 22% 38% 11% 2 1	180
December	1st to 10th	Day	36% 27% 21% 9% 6% 1	180
	11th to 20th	Day	34% 23% 29% 10% 4	180
	21st to end	Day	41% 18% 27% 10% 4	198
January	1st to 10th	Night	32% 21% 27% 16% 3	760
	11th to 20th	Night	34% 18% 28% 18% 3	760
	21st to end	Night	33% 19% 26% 19% 3	836
February	1st to 10th	Night	31% 17% 28% 23% 3	760
	11th to 20th	Night	32% 21% 30% 16% 1	743
	21st to end	Night	31% 17% 30% 21% 1	628
March	1st to 10th	Night	28% 17% 30% 23% 3	760
	11th to 20th	Night	31% 18% 24% 20% 7% 1	760
	21st to end	Night	26% 16% 31% 22% 5% 1	836
April	1st to 10th	Night	30% 14% 28% 22% 6%	760
	11th to 20th	Night	23% 13% 30% 23% 11%	711
	21st to end	Night	21% 10% 31% 30% 7% 1	567
May	1st to 10th	Night	23% 10% 24% 32% 10% 1	540
	11th to 20th	Night	24% 5% 25% 34% 12%	529
	21st to end	Night	11% 5% 25% 32% 24% 3	389
June	1st to 10th	Night	12% 3 24% 42% 18% 1	360
	11th to 20th	Night	13% 6% 20% 39% 19% 2	360
	21st to end	Night	14% 3 26% 37% 20% 1	360
July	1st to 10th	Night	11% 1 18% 43% 22% 4	358
	11th to 20th	Night	12% 2 14% 38% 31% 4	522
	21st to end	Night	14% 2 13% 41% 27% 2	591
August	1st to 10th	Night	11% 1 13% 44% 29% 2	537
	11th to 20th	Night	13% 2 12% 37% 32% 4	534
	21st to end	Night	14% 2 15% 35% 29% 5%	723
September	1st to 10th	Night	17% 3 16% 33% 27% 3	720
	11th to 20th	Night	13% 2 16% 37% 27% 5%	720
	21st to end	Night	21% 6% 21% 29% 20% 3	720
October	1st to 10th	Night	19% 6% 22% 29% 21% 2	720
	11th to 20th	Night	24% 11% 26% 29% 9% 1	720
	21st to end	Night	30% 11% 24% 27% 7%	792
November	1st to 10th	Night	19% 11% 25% 33% 11% 1	740
	11th to 20th	Night	30% 14% 24% 24% 7% 1	760
	21st to end	Night	30% 13% 29% 22% 6%	760
December	1st to 10th	Night	34% 16% 27% 18% 5%	760
	11th to 20th	Night	32% 20% 25% 20% 3	760
	21st to end	Night	33% 17% 26% 22% 2	836

Page generated at 2024-04-07 09:28:14. Version ac07

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