KK's Hill
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the KK's Hill clear sky chart from 2005-11-06 to 2024-02-15.

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	18% 11% 4 7% 6% 3 5% 4 5% 7% 31%	78389
	Night	18% 11% 4 7% 5% 3 4 4 5% 6% 32%	80668
Transparency	Day	52% 7% 11% 18% 11% 1	78110
	Night	53% 7% 11% 18% 11% 2	80466
Seeing	Day	25% 14% 24% 21% 12% 5%	13786
	Night	24% 12% 23% 27% 13% 1	23770

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% 21% 8% 10% 6% 2 3 3 3 5% 20%	2836
	11th to 20th	Day	17% 21% 10% 11% 9% 3 3 3 2 4 16%	2840
	21st to end	Day	24% 20% 7% 9% 7% 3 4 3 3 4 16%	3124
February	1st to 10th	Day	23% 13% 6% 8% 6% 3 4 3 4 6% 23%	1710
	11th to 20th	Day	22% 16% 6% 9% 6% 3 4 3 4 6% 22%	1609
	21st to end	Day	22% 17% 4 9% 4 2 4 3 3 5% 27%	1516
March	1st to 10th	Day	16% 12% 6% 7% 5% 2 3 4 5% 6% 34%	1980
	11th to 20th	Day	20% 13% 4 6% 5% 3 4 4 5% 7% 29%	1980
	21st to end	Day	20% 12% 4 8% 6% 3 4 4 5% 5% 28%	2178
April	1st to 10th	Day	17% 11% 3 7% 6% 4 4 4 5% 7% 31%	2060
	11th to 20th	Day	18% 9% 3 6% 5% 2 5% 4 5% 6% 36%	2143
	21st to end	Day	21% 8% 3 6% 5% 3 5% 5% 6% 6% 32%	2340
May	1st to 10th	Day	20% 9% 3 6% 7% 3 5% 5% 5% 6% 29%	2340
	11th to 20th	Day	23% 8% 3 6% 6% 4 5% 4 5% 7% 30%	2301
	21st to end	Day	13% 6% 3 5% 6% 4 6% 6% 6% 8% 37%	2567
June	1st to 10th	Day	14% 6% 3 6% 6% 3 5% 5% 7% 9% 36%	2520
	11th to 20th	Day	15% 7% 2 5% 5% 4 6% 6% 6% 8% 35%	2520
	21st to end	Day	15% 5% 3 5% 6% 3 5% 5% 7% 9% 36%	2500
July	1st to 10th	Day	14% 5% 2 7% 6% 4 6% 6% 6% 9% 35%	2340
	11th to 20th	Day	13% 6% 3 5% 5% 4 5% 7% 7% 8% 37%	2340
	21st to end	Day	15% 7% 2 5% 7% 4 7% 6% 6% 9% 33%	2547
August	1st to 10th	Day	13% 6% 3 6% 6% 4 6% 6% 8% 10% 31%	2327
	11th to 20th	Day	14% 6% 3 6% 6% 4 6% 6% 6% 11% 34%	2303
	21st to end	Day	13% 5% 2 5% 5% 4 6% 5% 7% 9% 39%	2443
September	1st to 10th	Day	16% 5% 2 5% 4 3 4 4 5% 7% 46%	2147
	11th to 20th	Day	13% 6% 2 5% 5% 4 3 5% 5% 8% 44%	1980
	21st to end	Day	18% 7% 3 5% 5% 4 5% 5% 5% 6% 36%	1980
October	1st to 10th	Day	16% 7% 3 6% 4 3 4 4 5% 7% 41%	1808
	11th to 20th	Day	20% 8% 2 5% 5% 2 4 4 4 7% 38%	1800
	21st to end	Day	25% 9% 3 5% 4 2 3 4 4 6% 36%	1980
November	1st to 10th	Day	14% 9% 2 5% 5% 2 4 3 4 5% 46%	1810
	11th to 20th	Day	17% 12% 4 5% 5% 3 4 3 6% 7% 33%	1656
	21st to end	Day	20% 13% 5% 7% 5% 3 4 4 5% 6% 29%	1520
December	1st to 10th	Day	25% 15% 8% 9% 6% 2 5% 4 4 4 19%	1520
	11th to 20th	Day	22% 18% 6% 8% 4 2 3 3 4 5% 26%	1910
	21st to end	Day	23% 20% 6% 8% 5% 3 4 4 4 6% 16%	2914
January	1st to 10th	Night	19% 21% 8% 10% 6% 3 4 3 3 4 19%	4109
	11th to 20th	Night	20% 19% 7% 11% 7% 4 4 3 3 3 18%	4120
	21st to end	Night	27% 17% 7% 8% 7% 3 3 3 3 3 19%	4532
February	1st to 10th	Night	20% 14% 5% 9% 6% 3 4 4 4 5% 27%	2470
	11th to 20th	Night	21% 14% 5% 9% 7% 4 5% 4 3 5% 23%	2328
	21st to end	Night	23% 14% 6% 6% 5% 3 4 5% 5% 4 26%	1739
March	1st to 10th	Night	18% 11% 5% 5% 6% 3 4 4 5% 6% 32%	1980
	11th to 20th	Night	23% 12% 4 5% 5% 3 4 4 4 6% 31%	1980
	21st to end	Night	22% 11% 3 6% 4 3 4 4 4 6% 32%	2178
April	1st to 10th	Night	21% 9% 3 6% 5% 3 5% 4 4 6% 33%	1900
	11th to 20th	Night	18% 7% 2 5% 5% 3 4 5% 6% 9% 37%	1775
	21st to end	Night	16% 8% 3 7% 6% 3 4 4 5% 6% 39%	1625
May	1st to 10th	Night	19% 8% 3 7% 5% 2 5% 5% 5% 8% 32%	1620
	11th to 20th	Night	21% 6% 2 6% 5% 3 4 4 5% 9% 34%	1592
	21st to end	Night	11% 5% 4 5% 5% 3 5% 5% 6% 9% 41%	1704
June	1st to 10th	Night	12% 5% 3 6% 6% 3 5% 5% 5% 8% 43%	1440
	11th to 20th	Night	11% 6% 2 6% 6% 4 5% 6% 6% 8% 38%	1440
	21st to end	Night	12% 5% 3 4 4 3 5% 4 7% 9% 42%	1454
July	1st to 10th	Night	11% 6% 3 6% 5% 3 6% 5% 7% 9% 39%	1620
	11th to 20th	Night	11% 5% 2 5% 5% 3 6% 4 6% 10% 44%	1620
	21st to end	Night	13% 5% 2 5% 5% 3 6% 6% 7% 10% 39%	1771
August	1st to 10th	Night	7% 6% 3 6% 7% 4 6% 6% 8% 9% 38%	1611
	11th to 20th	Night	12% 6% 2 5% 6% 4 5% 4 7% 8% 42%	1598
	21st to end	Night	11% 6% 2 5% 4 3 4 4 6% 8% 48%	1894
September	1st to 10th	Night	13% 6% 3 5% 5% 3 5% 4 5% 7% 45%	1808
	11th to 20th	Night	12% 5% 1 4 3 2 4 5% 5% 8% 50%	1980
	21st to end	Night	15% 6% 2 5% 6% 3 4 5% 5% 7% 42%	1980
October	1st to 10th	Night	16% 6% 3 4 4 3 4 5% 5% 7% 45%	2151
	11th to 20th	Night	17% 6% 2 5% 4 3 4 5% 5% 7% 42%	2160
	21st to end	Night	26% 7% 3 4 3 3 4 3 4 5% 39%	2376
November	1st to 10th	Night	14% 8% 3 6% 4 3 5% 4 4 5% 45%	2263
	11th to 20th	Night	19% 12% 4 6% 4 3 3 4 5% 6% 33%	2521
	21st to end	Night	20% 12% 4 8% 6% 3 5% 4 4 5% 31%	2660
December	1st to 10th	Night	23% 17% 7% 9% 5% 3 3 3 4 4 21%	2660
	11th to 20th	Night	21% 16% 7% 7% 5% 3 4 4 4 5% 24%	3285
	21st to end	Night	23% 18% 6% 8% 6% 3 4 3 4 5% 20%	4724

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	69% 5% 10% 11% 5% 1	2837
	11th to 20th	Day	74% 5% 7% 10% 5%	2840
	21st to end	Day	72% 4 7% 13% 4	3124
February	1st to 10th	Day	63% 5% 9% 16% 6% 1	1710
	11th to 20th	Day	65% 4 10% 14% 7%	1618
	21st to end	Day	62% 5% 9% 13% 9% 1	1516
March	1st to 10th	Day	52% 6% 10% 21% 11% 1	1980
	11th to 20th	Day	56% 6% 9% 18% 10% 1	1980
	21st to end	Day	58% 5% 8% 17% 11% 2	2178
April	1st to 10th	Day	52% 7% 10% 18% 11% 3	2060
	11th to 20th	Day	48% 6% 11% 14% 18% 3	2143
	21st to end	Day	51% 6% 12% 19% 10% 2	2340
May	1st to 10th	Day	54% 8% 9% 17% 10% 1	2340
	11th to 20th	Day	53% 8% 12% 16% 9% 1	2305
	21st to end	Day	43% 9% 17% 21% 9% 1	2567
June	1st to 10th	Day	43% 10% 13% 20% 13% 1	2520
	11th to 20th	Day	46% 9% 12% 21% 10% 1	2520
	21st to end	Day	42% 10% 14% 22% 10% 1	2500
July	1st to 10th	Day	44% 9% 12% 19% 13% 2	2275
	11th to 20th	Day	41% 10% 13% 21% 14% 2	2271
	21st to end	Day	45% 9% 12% 21% 12% 1	2405
August	1st to 10th	Day	44% 11% 15% 22% 8% 1	2314
	11th to 20th	Day	43% 9% 14% 22% 11%	2303
	21st to end	Day	39% 9% 15% 22% 12% 3	2443
September	1st to 10th	Day	38% 7% 11% 21% 20% 3	2147
	11th to 20th	Day	37% 7% 12% 26% 15% 3	1980
	21st to end	Day	46% 6% 12% 19% 16% 1	1980
October	1st to 10th	Day	42% 5% 13% 23% 14% 2	1808
	11th to 20th	Day	47% 6% 10% 25% 13%	1800
	21st to end	Day	51% 5% 10% 19% 14% 2	1980
November	1st to 10th	Day	41% 6% 9% 24% 17% 4	1810
	11th to 20th	Day	51% 5% 10% 17% 15% 3	1656
	21st to end	Day	57% 6% 10% 15% 12%	1520
December	1st to 10th	Day	69% 5% 8% 13% 4 1	1520
	11th to 20th	Day	62% 5% 9% 18% 5% 1	1906
	21st to end	Day	68% 5% 11% 11% 5%	2914
January	1st to 10th	Night	70% 5% 8% 11% 5% 1	4109
	11th to 20th	Night	71% 6% 10% 11% 2	4120
	21st to end	Night	72% 4 6% 13% 4 1	4532
February	1st to 10th	Night	61% 5% 10% 16% 8%	2470
	11th to 20th	Night	65% 5% 8% 14% 8%	2330
	21st to end	Night	61% 5% 9% 14% 8% 2	1739
March	1st to 10th	Night	53% 6% 8% 22% 10% 2	1980
	11th to 20th	Night	55% 5% 10% 18% 10% 1	1980
	21st to end	Night	54% 6% 9% 17% 11% 4	2178
April	1st to 10th	Night	53% 6% 8% 18% 13% 2	1900
	11th to 20th	Night	43% 6% 13% 18% 15% 4	1775
	21st to end	Night	45% 7% 12% 21% 13% 3	1625
May	1st to 10th	Night	50% 9% 10% 17% 12% 3	1620
	11th to 20th	Night	49% 8% 12% 16% 13% 2	1593
	21st to end	Night	38% 9% 17% 24% 11% 1	1705
June	1st to 10th	Night	38% 9% 13% 25% 15% 1	1440
	11th to 20th	Night	41% 11% 12% 21% 13% 2	1440
	21st to end	Night	37% 9% 16% 21% 15% 1	1454
July	1st to 10th	Night	39% 11% 15% 19% 14% 2	1575
	11th to 20th	Night	36% 9% 14% 23% 16% 2	1566
	21st to end	Night	37% 11% 15% 22% 15% 1	1672
August	1st to 10th	Night	39% 11% 16% 21% 11% 1	1600
	11th to 20th	Night	39% 9% 14% 23% 14% 1	1598
	21st to end	Night	33% 9% 14% 27% 15% 3	1894
September	1st to 10th	Night	38% 8% 13% 20% 17% 5%	1808
	11th to 20th	Night	31% 7% 14% 25% 21% 2	1980
	21st to end	Night	41% 8% 11% 21% 18% 1	1980
October	1st to 10th	Night	39% 7% 13% 24% 15% 3	2151
	11th to 20th	Night	41% 7% 10% 25% 16% 1	2160
	21st to end	Night	50% 4 7% 22% 16% 2	2376
November	1st to 10th	Night	41% 5% 11% 19% 18% 6%	2263
	11th to 20th	Night	52% 5% 9% 18% 14% 2	2521
	21st to end	Night	58% 4 8% 18% 10% 1	2660
December	1st to 10th	Night	68% 5% 7% 15% 4 1	2660
	11th to 20th	Night	63% 6% 10% 15% 6%	3288
	21st to end	Night	67% 6% 9% 12% 5%	4724

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	32% 31% 21% 11% 4 1	270
	11th to 20th	Day	42% 23% 28% 7%	270
	21st to end	Day	40% 25% 25% 6% 4	297
February	1st to 10th	Day	36% 26% 27% 9% 2	270
	11th to 20th	Day	48% 26% 23% 3	252
	21st to end	Day	44% 22% 26% 7% 1	234
March	1st to 10th	Day	33% 21% 29% 15% 3	420
	11th to 20th	Day	35% 20% 26% 13% 5% 1	420
	21st to end	Day	32% 19% 28% 16% 5%	462
April	1st to 10th	Day	33% 19% 22% 20% 6% 1	420
	11th to 20th	Day	26% 18% 26% 18% 8% 4	412
	21st to end	Day	31% 19% 25% 17% 7% 2	420
May	1st to 10th	Day	29% 18% 26% 14% 7% 5%	423
	11th to 20th	Day	25% 15% 27% 19% 11% 3	447
	21st to end	Day	15% 9% 29% 23% 16% 8%	485
June	1st to 10th	Day	15% 10% 28% 25% 17% 5%	450
	11th to 20th	Day	20% 9% 22% 28% 17% 5%	450
	21st to end	Day	15% 10% 28% 27% 17% 4	450
July	1st to 10th	Day	15% 6% 20% 25% 21% 13%	445
	11th to 20th	Day	13% 6% 22% 30% 21% 9%	444
	21st to end	Day	19% 6% 22% 26% 18% 9%	488
August	1st to 10th	Day	15% 6% 18% 31% 18% 11%	446
	11th to 20th	Day	17% 7% 18% 27% 21% 10%	439
	21st to end	Day	13% 7% 21% 27% 20% 12%	495
September	1st to 10th	Day	19% 6% 18% 26% 20% 10%	450
	11th to 20th	Day	14% 3 18% 29% 24% 12%	450
	21st to end	Day	23% 9% 23% 26% 15% 4	450
October	1st to 10th	Day	19% 9% 22% 26% 20% 5%	450
	11th to 20th	Day	26% 11% 27% 24% 10% 2	450
	21st to end	Day	31% 16% 25% 17% 10%	495
November	1st to 10th	Day	22% 12% 26% 26% 10% 5%	408
	11th to 20th	Day	33% 18% 22% 20% 5% 2	244
	21st to end	Day	28% 22% 35% 13% 2 1	180
December	1st to 10th	Day	33% 24% 26% 11% 3 2	180
	11th to 20th	Day	39% 22% 22% 14% 3	180
	21st to end	Day	40% 20% 21% 15% 4	240
January	1st to 10th	Night	33% 23% 26% 16% 3	760
	11th to 20th	Night	38% 17% 26% 17% 2	760
	21st to end	Night	31% 21% 29% 18% 1	836
February	1st to 10th	Night	30% 18% 26% 23% 2	760
	11th to 20th	Night	31% 24% 31% 14% 1	722
	21st to end	Night	33% 20% 28% 17% 1	592
March	1st to 10th	Night	28% 19% 27% 23% 3	720
	11th to 20th	Night	31% 18% 24% 20% 6% 1	720
	21st to end	Night	30% 16% 27% 23% 4 1	792
April	1st to 10th	Night	28% 17% 28% 22% 5%	720
	11th to 20th	Night	21% 15% 29% 24% 11%	711
	21st to end	Night	19% 12% 30% 30% 8%	545
May	1st to 10th	Night	23% 9% 28% 29% 10% 1	540
	11th to 20th	Night	23% 9% 24% 31% 13% 1	531
	21st to end	Night	15% 4 20% 30% 27% 4	544
June	1st to 10th	Night	11% 6% 23% 39% 21% 1	360
	11th to 20th	Night	16% 4 23% 35% 21% 2	360
	21st to end	Night	13% 3 21% 42% 20% 1	374
July	1st to 10th	Night	13% 3 15% 37% 28% 4	525
	11th to 20th	Night	12% 4 12% 36% 32% 4	522
	21st to end	Night	15% 3 13% 35% 30% 3	591
August	1st to 10th	Night	11% 3 12% 42% 29% 3	537
	11th to 20th	Night	14% 4 11% 37% 30% 4	534
	21st to end	Night	14% 3 13% 35% 30% 5%	706
September	1st to 10th	Night	14% 3 16% 35% 28% 4	720
	11th to 20th	Night	15% 4 15% 34% 29% 3	720
	21st to end	Night	18% 8% 20% 32% 20% 2	720
October	1st to 10th	Night	20% 6% 19% 32% 19% 3	720
	11th to 20th	Night	22% 11% 25% 29% 12% 1	720
	21st to end	Night	30% 11% 21% 27% 10% 1	792
November	1st to 10th	Night	19% 10% 24% 33% 13% 1	740
	11th to 20th	Night	30% 13% 24% 25% 7% 1	760
	21st to end	Night	27% 15% 27% 24% 6% 1	760
December	1st to 10th	Night	34% 17% 25% 19% 4	760
	11th to 20th	Night	30% 19% 24% 22% 5%	760
	21st to end	Night	32% 15% 27% 24% 2	836

Page generated at 2024-02-12 06:35:33. Version ac07

Copyright 2024 Attilla Danko