Kettle Moraine North
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kettle Moraine North clear sky chart from 2005-11-06 to 2025-08-05.

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	12% 8% 3 8% 5% 4 4 4 6% 7% 38%	125855
	Night	12% 9% 3 8% 5% 4 4 4 5% 7% 39%	122452
Transparency	Day	43% 6% 12% 24% 13% 1	129355
	Night	44% 5% 12% 23% 15% 2	127026
Seeing	Day	16% 12% 31% 24% 12% 4	16973
	Night	17% 11% 32% 28% 11% 1	26804

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	9% 9% 5% 13% 7% 5% 6% 4 6% 6% 30%	3617
	11th to 20th	Day	8% 10% 6% 12% 5% 5% 5% 6% 5% 6% 31%	3620
	21st to end	Day	13% 14% 7% 9% 4 4 3 3 4 6% 34%	3982
February	1st to 10th	Day	11% 13% 6% 10% 5% 4 4 5% 5% 6% 31%	1791
	11th to 20th	Day	12% 11% 4 8% 5% 4 5% 3 5% 6% 36%	1933
	21st to end	Day	11% 14% 4 9% 5% 3 5% 4 5% 6% 32%	1650
March	1st to 10th	Day	13% 8% 3 6% 4 3 4 4 5% 6% 44%	4480
	11th to 20th	Day	10% 7% 3 8% 5% 5% 4 3 5% 7% 42%	4672
	21st to end	Day	23% 12% 4 10% 5% 3 3 3 4 4 29%	5967
April	1st to 10th	Day	17% 13% 4 8% 4 5% 4 4 5% 6% 31%	2400
	11th to 20th	Day	18% 11% 3 7% 4 4 4 3 5% 7% 34%	2374
	21st to end	Day	18% 10% 3 8% 5% 4 5% 3 6% 6% 32%	2545
May	1st to 10th	Day	13% 9% 2 7% 4 4 4 4 5% 7% 42%	5925
	11th to 20th	Day	11% 5% 2 7% 5% 5% 4 4 6% 8% 43%	6319
	21st to end	Day	15% 6% 2 6% 4 4 4 4 6% 9% 39%	6935
June	1st to 10th	Day	10% 6% 2 7% 5% 5% 4 4 6% 8% 44%	2800
	11th to 20th	Day	11% 6% 3 7% 5% 4 5% 4 6% 8% 41%	2800
	21st to end	Day	9% 6% 2 7% 4 4 5% 4 6% 10% 43%	2800
July	1st to 10th	Day	12% 6% 3 7% 4 5% 5% 4 7% 10% 38%	6360
	11th to 20th	Day	7% 4 2 5% 4 5% 5% 5% 7% 9% 48%	6360
	21st to end	Day	8% 5% 2 6% 5% 4 4 4 7% 9% 45%	6924
August	1st to 10th	Day	9% 6% 2 6% 5% 5% 6% 5% 7% 8% 41%	4480
	11th to 20th	Day	12% 5% 2 5% 5% 5% 5% 4 7% 8% 43%	3842
	21st to end	Day	10% 6% 3 7% 4 5% 5% 4 6% 8% 43%	4180
September	1st to 10th	Day	11% 6% 2 7% 4 5% 4 4 5% 8% 44%	2280
	11th to 20th	Day	11% 5% 2 5% 4 4 4 3 6% 7% 48%	2170
	21st to end	Day	13% 7% 2 5% 5% 5% 4 4 5% 7% 42%	2090
October	1st to 10th	Day	14% 6% 2 6% 4 3 4 4 5% 7% 43%	2014
	11th to 20th	Day	21% 8% 2 7% 5% 5% 5% 4 6% 7% 30%	1862
	21st to end	Day	16% 10% 3 9% 5% 4 4 4 5% 6% 35%	1881
November	1st to 10th	Day	12% 9% 3 7% 4 4 4 3 5% 7% 42%	1762
	11th to 20th	Day	11% 12% 4 10% 7% 5% 5% 4 6% 8% 30%	1800
	21st to end	Day	16% 11% 4 8% 6% 4 4 2 5% 6% 35%	1640
December	1st to 10th	Day	8% 9% 4 9% 5% 4 7% 5% 7% 9% 33%	2610
	11th to 20th	Day	11% 17% 5% 9% 5% 5% 5% 4 6% 7% 26%	3008
	21st to end	Day	19% 22% 8% 12% 5% 3 3 3 4 5% 17%	3982
January	1st to 10th	Night	10% 10% 5% 11% 7% 4 4 3 4 5% 37%	6348
	11th to 20th	Night	10% 11% 5% 13% 6% 5% 6% 5% 5% 6% 27%	6360
	21st to end	Night	10% 14% 5% 10% 5% 4 4 3 5% 6% 33%	6996
February	1st to 10th	Night	12% 13% 4 9% 5% 5% 4 3 4 6% 35%	2605
	11th to 20th	Night	11% 9% 3 8% 6% 5% 5% 4 5% 5% 39%	2352
	21st to end	Night	15% 12% 4 6% 4 4 4 4 6% 6% 35%	1980
March	1st to 10th	Night	14% 7% 3 6% 3 3 4 3 4 6% 45%	5373
	11th to 20th	Night	9% 7% 2 6% 5% 4 5% 4 6% 8% 44%	5316
	21st to end	Night	18% 11% 4 10% 5% 4 4 3 4 5% 32%	4962
April	1st to 10th	Night	17% 11% 3 6% 4 4 3 3 4 7% 36%	2000
	11th to 20th	Night	20% 8% 3 6% 4 4 3 3 4 6% 38%	1975
	21st to end	Night	16% 9% 3 6% 4 4 4 3 5% 6% 39%	1853
May	1st to 10th	Night	14% 7% 3 7% 4 4 4 3 4 7% 42%	3958
	11th to 20th	Night	9% 5% 3 9% 5% 5% 5% 5% 6% 7% 41%	3596
	21st to end	Night	18% 8% 2 6% 5% 4 4 3 4 6% 39%	3942
June	1st to 10th	Night	11% 5% 1 6% 3 4 4 4 6% 8% 47%	1600
	11th to 20th	Night	12% 5% 2 6% 4 4 4 4 6% 8% 44%	1600
	21st to end	Night	9% 6% 2 7% 4 3 4 4 6% 7% 49%	1600
July	1st to 10th	Night	10% 6% 3 6% 3 4 4 4 6% 9% 45%	3618
	11th to 20th	Night	6% 5% 2 5% 4 4 4 4 6% 8% 53%	3617
	21st to end	Night	5% 5% 2 5% 4 4 5% 4 6% 7% 53%	3947
August	1st to 10th	Night	10% 5% 2 5% 4 4 3 4 6% 8% 49%	2549
	11th to 20th	Night	9% 6% 2 6% 5% 4 5% 4 5% 7% 47%	2984
	21st to end	Night	8% 5% 2 5% 4 4 5% 4 6% 9% 48%	3476
September	1st to 10th	Night	9% 5% 2 5% 4 3 3 3 5% 7% 54%	1900
	11th to 20th	Night	12% 4 2 4 2 3 4 3 6% 7% 53%	1990
	21st to end	Night	12% 7% 2 5% 4 3 4 3 5% 7% 48%	2090
October	1st to 10th	Night	11% 7% 2 7% 4 4 3 3 5% 6% 49%	2163
	11th to 20th	Night	15% 8% 2 7% 4 4 4 4 5% 7% 40%	2317
	21st to end	Night	17% 10% 3 6% 4 4 4 4 6% 7% 35%	2717
November	1st to 10th	Night	13% 7% 3 6% 5% 4 4 4 5% 6% 45%	2536
	11th to 20th	Night	14% 10% 4 9% 6% 5% 5% 4 5% 7% 33%	2600
	21st to end	Night	16% 10% 3 7% 5% 5% 5% 4 5% 6% 34%	2757
December	1st to 10th	Night	9% 10% 3 6% 4 3 4 4 6% 8% 42%	4580
	11th to 20th	Night	14% 16% 6% 10% 6% 4 4 3 5% 4 28%	5199
	21st to end	Night	19% 17% 5% 11% 6% 4 4 3 4 5% 21%	6996

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	53% 6% 15% 19% 7%	3618
	11th to 20th	Day	52% 4 11% 15% 16% 2	3620
	21st to end	Day	52% 4 11% 20% 14%	3982
February	1st to 10th	Day	51% 5% 13% 19% 10% 1	1791
	11th to 20th	Day	49% 6% 10% 22% 11% 2	1943
	21st to end	Day	52% 5% 11% 19% 10% 3	1650
March	1st to 10th	Day	38% 7% 11% 24% 14% 6%	4480
	11th to 20th	Day	40% 4 15% 23% 15% 2	4672
	21st to end	Day	59% 5% 10% 15% 11% 1	5969
April	1st to 10th	Day	53% 7% 11% 19% 10% 1	2400
	11th to 20th	Day	50% 6% 9% 21% 12% 3	2374
	21st to end	Day	50% 7% 11% 18% 11% 1	2545
May	1st to 10th	Day	41% 6% 11% 24% 16% 2	5960
	11th to 20th	Day	38% 7% 11% 27% 15% 1	6323
	21st to end	Day	40% 6% 11% 26% 14% 2	6949
June	1st to 10th	Day	36% 7% 12% 27% 15% 2	2800
	11th to 20th	Day	39% 8% 13% 24% 15% 1	2800
	21st to end	Day	37% 8% 13% 25% 15% 2	2800
July	1st to 10th	Day	39% 7% 12% 31% 10% 1	6291
	11th to 20th	Day	30% 7% 15% 32% 15% 1	6285
	21st to end	Day	34% 8% 15% 23% 19% 2	6728
August	1st to 10th	Day	37% 7% 15% 27% 12% 1	4465
	11th to 20th	Day	37% 8% 12% 31% 11% 1	3881
	21st to end	Day	39% 6% 13% 24% 17% 1	4179
September	1st to 10th	Day	38% 7% 11% 27% 15% 1	2280
	11th to 20th	Day	34% 7% 13% 31% 14% 1	2170
	21st to end	Day	40% 5% 13% 29% 12%	2090
October	1st to 10th	Day	24% 4 7% 38% 25% 2	3352
	11th to 20th	Day	38% 5% 10% 24% 21% 1	3078
	21st to end	Day	43% 4 11% 26% 14% 1	3081
November	1st to 10th	Day	42% 5% 14% 24% 14% 2	1762
	11th to 20th	Day	52% 5% 14% 19% 9% 1	1800
	21st to end	Day	51% 4 14% 23% 7% 1	1640
December	1st to 10th	Day	46% 7% 20% 22% 5%	2610
	11th to 20th	Day	56% 4 13% 16% 10% 1	3005
	21st to end	Day	70% 4 8% 11% 8%	3982
January	1st to 10th	Night	51% 4 8% 22% 15% 1	6348
	11th to 20th	Night	58% 4 9% 11% 17% 2	6360
	21st to end	Night	52% 5% 13% 18% 12%	6996
February	1st to 10th	Night	51% 4 11% 19% 13% 2	2605
	11th to 20th	Night	46% 5% 10% 23% 14% 2	2353
	21st to end	Night	49% 5% 13% 20% 12% 2	1980
March	1st to 10th	Night	40% 5% 14% 24% 14% 4	5373
	11th to 20th	Night	36% 5% 15% 25% 15% 4	5316
	21st to end	Night	55% 5% 8% 17% 13% 1	4962
April	1st to 10th	Night	47% 5% 10% 19% 18% 1	2000
	11th to 20th	Night	48% 5% 9% 20% 16% 3	1975
	21st to end	Night	44% 5% 12% 23% 14% 2	1853
May	1st to 10th	Night	42% 5% 11% 19% 20% 2	3985
	11th to 20th	Night	39% 8% 13% 21% 17% 2	3597
	21st to end	Night	45% 5% 8% 24% 12% 5%	3950
June	1st to 10th	Night	33% 7% 13% 29% 18% 1	1600
	11th to 20th	Night	36% 7% 11% 25% 19% 2	1600
	21st to end	Night	35% 6% 15% 23% 18% 2	1600
July	1st to 10th	Night	35% 6% 14% 31% 10% 3	3580
	11th to 20th	Night	28% 6% 15% 31% 18% 2	3572
	21st to end	Night	29% 6% 16% 25% 22% 3	3832
August	1st to 10th	Night	31% 7% 15% 25% 20% 2	2540
	11th to 20th	Night	34% 7% 12% 30% 16%	3011
	21st to end	Night	31% 6% 14% 25% 21% 3	3476
September	1st to 10th	Night	31% 7% 10% 26% 25% 2	1900
	11th to 20th	Night	31% 5% 11% 35% 18% 1	1990
	21st to end	Night	36% 6% 10% 31% 16% 1	2090
October	1st to 10th	Night	26% 4 7% 39% 23% 1	3605
	11th to 20th	Night	33% 4 13% 28% 19% 3	3840
	21st to end	Night	43% 4 10% 25% 17%	4467
November	1st to 10th	Night	40% 5% 12% 25% 16% 2	2536
	11th to 20th	Night	50% 5% 13% 19% 11% 2	2600
	21st to end	Night	50% 5% 14% 22% 7% 1	2757
December	1st to 10th	Night	39% 5% 20% 26% 7% 3	4580
	11th to 20th	Night	59% 5% 10% 13% 12% 1	5201
	21st to end	Night	66% 4 10% 13% 7%	6996

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	16% 17% 36% 24% 6% 1	300
	11th to 20th	Day	14% 24% 34% 22% 5%	300
	21st to end	Day	22% 14% 40% 20% 4 1	330
February	1st to 10th	Day	15% 22% 42% 15% 5% 1	300
	11th to 20th	Day	20% 26% 33% 15% 5%	300
	21st to end	Day	22% 24% 41% 12% 1	249
March	1st to 10th	Day	18% 27% 41% 11% 2	300
	11th to 20th	Day	24% 20% 32% 17% 5% 2	321
	21st to end	Day	27% 13% 32% 21% 6% 1	550
April	1st to 10th	Day	27% 13% 36% 19% 5%	500
	11th to 20th	Day	24% 20% 28% 17% 10% 2	492
	21st to end	Day	23% 14% 29% 22% 11% 1	500
May	1st to 10th	Day	20% 12% 35% 23% 8% 2	527
	11th to 20th	Day	16% 13% 31% 25% 12% 3	725
	21st to end	Day	16% 10% 31% 25% 13% 5%	789
June	1st to 10th	Day	11% 9% 33% 31% 12% 4	730
	11th to 20th	Day	14% 9% 32% 28% 13% 4	730
	21st to end	Day	13% 9% 33% 29% 12% 4	730
July	1st to 10th	Day	9% 5% 22% 32% 23% 8%	721
	11th to 20th	Day	9% 7% 28% 30% 20% 6%	718
	21st to end	Day	6% 4 31% 33% 20% 7%	794
August	1st to 10th	Day	8% 4 26% 34% 19% 9%	697
	11th to 20th	Day	14% 4 17% 30% 24% 12%	487
	21st to end	Day	13% 6% 23% 28% 21% 9%	539
September	1st to 10th	Day	12% 8% 26% 28% 19% 8%	490
	11th to 20th	Day	11% 5% 20% 34% 21% 9%	490
	21st to end	Day	18% 12% 26% 23% 16% 5%	490
October	1st to 10th	Day	18% 12% 27% 25% 15% 4	414
	11th to 20th	Day	20% 21% 32% 19% 7%	300
	21st to end	Day	25% 15% 39% 16% 4 1	330
November	1st to 10th	Day	18% 18% 35% 20% 8% 2	300
	11th to 20th	Day	18% 21% 38% 18% 5%	300
	21st to end	Day	24% 16% 39% 17% 5%	300
December	1st to 10th	Day	19% 20% 40% 16% 5% 1	300
	11th to 20th	Day	21% 22% 35% 14% 6% 1	300
	21st to end	Day	27% 19% 34% 17% 2 2	330
January	1st to 10th	Night	17% 17% 38% 22% 5%	1000
	11th to 20th	Night	20% 15% 39% 20% 6% 1	1000
	21st to end	Night	18% 13% 38% 25% 5%	1100
February	1st to 10th	Night	20% 16% 36% 24% 5% 1	1000
	11th to 20th	Night	15% 18% 37% 24% 5%	797
	21st to end	Night	23% 14% 39% 19% 4	660
March	1st to 10th	Night	20% 13% 36% 23% 7% 1	800
	11th to 20th	Night	15% 15% 38% 25% 7%	776
	21st to end	Night	21% 10% 30% 32% 7% 1	660
April	1st to 10th	Night	22% 12% 39% 22% 7%	600
	11th to 20th	Night	22% 11% 34% 25% 7% 1	593
	21st to end	Night	20% 10% 32% 29% 9% 1	600
May	1st to 10th	Night	18% 10% 32% 33% 7% 1	600
	11th to 20th	Night	17% 8% 31% 31% 12% 1	591
	21st to end	Night	16% 5% 25% 36% 17% 2	650
June	1st to 10th	Night	11% 6% 28% 39% 16% 1	600
	11th to 20th	Night	13% 5% 31% 36% 13% 2	600
	21st to end	Night	11% 6% 26% 41% 16% 1	600
July	1st to 10th	Night	8% 2 19% 42% 26% 3	585
	11th to 20th	Night	7% 2 25% 38% 25% 3	582
	21st to end	Night	6% 2 22% 44% 24% 2	657
August	1st to 10th	Night	7% 2 16% 45% 26% 4	579
	11th to 20th	Night	9% 2 16% 41% 26% 6%	564
	21st to end	Night	9% 2 21% 40% 24% 3	627
September	1st to 10th	Night	10% 4 24% 33% 25% 5%	570
	11th to 20th	Night	12% 4 22% 32% 25% 6%	660
	21st to end	Night	15% 8% 26% 27% 20% 3	760
October	1st to 10th	Night	14% 9% 28% 31% 17% 2	760
	11th to 20th	Night	19% 13% 33% 27% 8% 1	760
	21st to end	Night	22% 11% 33% 25% 9%	836
November	1st to 10th	Night	16% 12% 37% 24% 9% 1	780
	11th to 20th	Night	21% 18% 33% 22% 6%	800
	21st to end	Night	21% 14% 36% 22% 6%	957
December	1st to 10th	Night	20% 17% 37% 22% 5%	1000
	11th to 20th	Night	23% 14% 39% 19% 5% 1	1000
	21st to end	Night	27% 14% 35% 21% 3	1100

Page generated at 2025-08-02 00:32:29. Version ac07

Copyright © 2025 Attilla Danko.