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 2024-04-03.

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	13% 9% 4 7% 6% 3 5% 5% 5% 7% 36%	78719
	Night	13% 9% 4 7% 5% 3 4 5% 5% 7% 38%	81464
Transparency	Day	46% 7% 13% 22% 11% 1	78420
	Night	46% 6% 12% 22% 13% 1	81284
Seeing	Day	16% 12% 31% 25% 13% 4	14999
	Night	17% 10% 32% 28% 11% 1	25072

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	12% 12% 6% 10% 7% 4 5% 5% 5% 5% 29%	2527
	11th to 20th	Day	11% 11% 5% 13% 7% 4 6% 9% 6% 6% 21%	2530
	21st to end	Day	18% 16% 9% 11% 5% 2 4 4 3 6% 22%	2783
February	1st to 10th	Day	11% 11% 6% 9% 6% 2 4 6% 5% 7% 32%	1701
	11th to 20th	Day	13% 10% 4 7% 6% 3 4 5% 4 6% 36%	1833
	21st to end	Day	12% 13% 5% 8% 6% 3 5% 5% 5% 6% 32%	1570
March	1st to 10th	Day	14% 10% 5% 7% 5% 3 4 5% 5% 6% 37%	1900
	11th to 20th	Day	11% 11% 4 6% 6% 4 5% 4 5% 6% 37%	1958
	21st to end	Day	19% 10% 5% 7% 7% 3 5% 5% 5% 5% 30%	2508
April	1st to 10th	Day	17% 12% 5% 7% 4 3 5% 4 5% 7% 30%	2184
	11th to 20th	Day	18% 10% 3 7% 5% 3 4 4 5% 7% 33%	2134
	21st to end	Day	19% 9% 3 7% 5% 3 4 5% 5% 6% 32%	2290
May	1st to 10th	Day	16% 8% 3 6% 6% 4 5% 6% 6% 8% 34%	2361
	11th to 20th	Day	16% 6% 3 6% 7% 4 5% 4 5% 7% 38%	2479
	21st to end	Day	13% 6% 3 6% 5% 3 4 5% 7% 9% 40%	2725
June	1st to 10th	Day	10% 5% 3 5% 5% 3 4 5% 6% 9% 44%	2520
	11th to 20th	Day	11% 5% 2 6% 5% 3 5% 5% 6% 9% 42%	2520
	21st to end	Day	9% 5% 2 5% 6% 3 6% 5% 6% 10% 44%	2520
July	1st to 10th	Day	7% 4 2 4 4 3 5% 5% 7% 11% 47%	2520
	11th to 20th	Day	8% 4 2 4 5% 4 5% 6% 7% 9% 46%	2520
	21st to end	Day	7% 4 2 4 5% 2 5% 5% 7% 10% 48%	2743
August	1st to 10th	Day	7% 4 2 5% 6% 4 6% 6% 7% 10% 42%	2507
	11th to 20th	Day	12% 5% 2 4 6% 4 5% 5% 6% 8% 43%	2199
	21st to end	Day	11% 5% 3 5% 5% 3 4 5% 5% 8% 45%	2376
September	1st to 10th	Day	12% 6% 3 6% 5% 4 4 5% 6% 8% 42%	2160
	11th to 20th	Day	12% 5% 2 4 5% 3 4 4 6% 7% 47%	2056
	21st to end	Day	13% 7% 2 5% 6% 4 4 6% 5% 7% 41%	1980
October	1st to 10th	Day	15% 6% 3 6% 5% 3 4 5% 5% 7% 42%	1908
	11th to 20th	Day	22% 8% 3 6% 6% 4 4 5% 6% 7% 29%	1764
	21st to end	Day	17% 10% 3 8% 5% 3 4 4 5% 6% 34%	1782
November	1st to 10th	Day	11% 8% 4 6% 5% 2 5% 4 6% 7% 42%	1672
	11th to 20th	Day	11% 10% 5% 9% 7% 4 6% 4 6% 8% 31%	1710
	21st to end	Day	17% 9% 4 6% 6% 3 4 3 4 6% 36%	1558
December	1st to 10th	Day	14% 11% 5% 8% 6% 3 7% 5% 5% 8% 28%	1520
	11th to 20th	Day	11% 14% 5% 7% 7% 3 6% 6% 6% 8% 28%	1918
	21st to end	Day	18% 19% 9% 11% 7% 2 4 3 4 5% 18%	2783
January	1st to 10th	Night	14% 13% 7% 10% 5% 3 3 3 4 4 33%	4428
	11th to 20th	Night	13% 12% 6% 13% 8% 4 6% 8% 6% 6% 21%	4440
	21st to end	Night	15% 15% 7% 11% 6% 3 4 4 4 5% 25%	4884
February	1st to 10th	Night	12% 12% 5% 8% 6% 4 4 4 5% 6% 35%	2475
	11th to 20th	Night	11% 8% 4 7% 6% 3 6% 5% 5% 6% 39%	2232
	21st to end	Night	16% 12% 4 6% 4 3 4 4 5% 6% 36%	1884
March	1st to 10th	Night	15% 8% 4 6% 4 2 5% 4 5% 7% 38%	2280
	11th to 20th	Night	12% 7% 3 5% 5% 3 5% 5% 5% 8% 42%	2236
	21st to end	Night	17% 9% 4 8% 5% 3 5% 5% 5% 6% 34%	2090
April	1st to 10th	Night	17% 11% 4 6% 5% 3 4 5% 5% 7% 34%	1820
	11th to 20th	Night	20% 8% 3 6% 5% 3 4 4 5% 6% 38%	1775
	21st to end	Night	17% 8% 3 6% 5% 4 4 4 5% 6% 39%	1669
May	1st to 10th	Night	14% 8% 4 7% 6% 3 6% 5% 5% 8% 34%	1597
	11th to 20th	Night	16% 7% 3 7% 5% 3 4 6% 6% 8% 37%	1416
	21st to end	Night	12% 6% 3 4 5% 3 6% 5% 6% 9% 42%	1551
June	1st to 10th	Night	11% 4 2 5% 4 3 5% 5% 6% 9% 48%	1440
	11th to 20th	Night	12% 4 2 5% 5% 3 4 5% 6% 8% 46%	1440
	21st to end	Night	9% 4 2 6% 4 3 4 4 6% 7% 51%	1440
July	1st to 10th	Night	6% 3 3 4 4 2 3 6% 6% 9% 54%	1440
	11th to 20th	Night	6% 3 2 5% 4 2 4 6% 7% 9% 52%	1440
	21st to end	Night	6% 3 2 4 4 3 5% 5% 6% 8% 54%	1575
August	1st to 10th	Night	6% 3 2 4 5% 3 4 5% 7% 10% 50%	1432
	11th to 20th	Night	7% 4 2 4 5% 3 5% 5% 5% 8% 51%	1699
	21st to end	Night	9% 4 2 4 4 3 5% 5% 5% 7% 51%	1980
September	1st to 10th	Night	10% 5% 2 5% 4 2 4 4 5% 7% 53%	1800
	11th to 20th	Night	12% 4 2 4 3 2 4 4 5% 7% 54%	1885
	21st to end	Night	13% 7% 2 4 5% 2 4 4 4 7% 48%	1980
October	1st to 10th	Night	12% 6% 2 6% 5% 3 3 4 5% 6% 47%	2049
	11th to 20th	Night	16% 7% 2 6% 5% 4 5% 4 5% 7% 39%	2195
	21st to end	Night	17% 10% 3 6% 5% 3 4 5% 6% 7% 34%	2574
November	1st to 10th	Night	12% 6% 3 5% 5% 3 4 4 5% 6% 46%	2406
	11th to 20th	Night	14% 8% 4 8% 6% 4 5% 5% 5% 7% 33%	2470
	21st to end	Night	16% 9% 3 5% 6% 3 5% 5% 5% 6% 36%	2619
December	1st to 10th	Night	14% 12% 5% 7% 7% 3 5% 5% 6% 7% 31%	2660
	11th to 20th	Night	13% 13% 5% 8% 7% 4 5% 5% 5% 6% 29%	3279
	21st to end	Night	20% 18% 5% 8% 7% 3 4 4 4 6% 21%	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	57% 6% 15% 16% 6%	2528
	11th to 20th	Day	60% 5% 13% 17% 5%	2530
	21st to end	Day	66% 4 9% 16% 5%	2783
February	1st to 10th	Day	51% 5% 13% 20% 9% 1	1701
	11th to 20th	Day	49% 6% 10% 22% 12% 2	1843
	21st to end	Day	52% 5% 11% 19% 10% 3	1570
March	1st to 10th	Day	46% 8% 13% 21% 10% 2	1900
	11th to 20th	Day	46% 5% 12% 20% 14% 2	1958
	21st to end	Day	55% 7% 11% 19% 7% 1	2508
April	1st to 10th	Day	54% 7% 11% 18% 10%	2184
	11th to 20th	Day	51% 6% 8% 20% 12% 3	2134
	21st to end	Day	51% 7% 11% 18% 11% 2	2290
May	1st to 10th	Day	47% 7% 13% 21% 10% 1	2361
	11th to 20th	Day	46% 7% 11% 23% 12% 2	2483
	21st to end	Day	41% 8% 12% 23% 14% 2	2725
June	1st to 10th	Day	36% 7% 12% 28% 14% 2	2520
	11th to 20th	Day	38% 7% 13% 24% 16% 1	2520
	21st to end	Day	36% 9% 14% 25% 15% 1	2520
July	1st to 10th	Day	30% 8% 14% 31% 14% 3	2451
	11th to 20th	Day	32% 9% 15% 26% 16% 3	2445
	21st to end	Day	29% 8% 16% 26% 16% 4	2591
August	1st to 10th	Day	33% 10% 16% 27% 12% 2	2492
	11th to 20th	Day	38% 8% 14% 27% 13% 1	2199
	21st to end	Day	37% 7% 12% 25% 17% 2	2376
September	1st to 10th	Day	39% 8% 11% 26% 14% 1	2160
	11th to 20th	Day	35% 7% 13% 31% 13% 1	2056
	21st to end	Day	41% 5% 14% 28% 11%	1980
October	1st to 10th	Day	41% 7% 10% 27% 15% 1	1908
	11th to 20th	Day	53% 7% 12% 18% 10% 1	1764
	21st to end	Day	51% 6% 13% 18% 11%	1782
November	1st to 10th	Day	41% 5% 14% 24% 14% 2	1672
	11th to 20th	Day	51% 5% 14% 20% 8% 1	1710
	21st to end	Day	50% 4 15% 23% 7% 1	1558
December	1st to 10th	Day	53% 7% 16% 16% 7% 1	1520
	11th to 20th	Day	54% 4 17% 15% 8% 2	1915
	21st to end	Day	70% 4 10% 11% 5%	2783
January	1st to 10th	Night	55% 5% 9% 19% 10% 1	4428
	11th to 20th	Night	64% 5% 10% 13% 8%	4440
	21st to end	Night	62% 5% 11% 16% 6%	4884
February	1st to 10th	Night	51% 5% 10% 20% 12% 2	2475
	11th to 20th	Night	46% 5% 11% 23% 14% 2	2233
	21st to end	Night	49% 5% 12% 20% 12% 2	1884
March	1st to 10th	Night	46% 6% 13% 21% 11% 2	2280
	11th to 20th	Night	39% 7% 14% 22% 16% 2	2236
	21st to end	Night	51% 6% 8% 21% 11% 2	2090
April	1st to 10th	Night	49% 5% 10% 18% 17% 1	1820
	11th to 20th	Night	48% 5% 9% 19% 17% 3	1775
	21st to end	Night	45% 5% 13% 21% 14% 1	1669
May	1st to 10th	Night	48% 7% 12% 22% 11% 1	1597
	11th to 20th	Night	45% 7% 11% 22% 13% 2	1417
	21st to end	Night	38% 8% 13% 24% 15% 2	1552
June	1st to 10th	Night	32% 7% 13% 29% 18% 1	1440
	11th to 20th	Night	35% 7% 11% 26% 19% 2	1440
	21st to end	Night	33% 7% 16% 25% 18% 2	1440
July	1st to 10th	Night	27% 8% 14% 29% 20% 4	1400
	11th to 20th	Night	26% 9% 13% 29% 19% 4	1392
	21st to end	Night	26% 7% 15% 29% 18% 5%	1487
August	1st to 10th	Night	27% 9% 16% 29% 16% 3	1423
	11th to 20th	Night	29% 8% 15% 30% 17% 1	1699
	21st to end	Night	31% 6% 12% 29% 20% 3	1980
September	1st to 10th	Night	32% 7% 10% 25% 24% 2	1800
	11th to 20th	Night	31% 5% 11% 35% 16% 1	1885
	21st to end	Night	36% 7% 10% 31% 15% 1	1980
October	1st to 10th	Night	38% 6% 9% 29% 17% 1	2049
	11th to 20th	Night	45% 6% 14% 20% 14% 1	2195
	21st to end	Night	48% 5% 14% 21% 11%	2574
November	1st to 10th	Night	39% 5% 11% 26% 17% 2	2406
	11th to 20th	Night	50% 5% 14% 19% 11% 1	2470
	21st to end	Night	49% 5% 15% 22% 8% 1	2619
December	1st to 10th	Night	52% 6% 14% 19% 8% 1	2660
	11th to 20th	Night	55% 6% 12% 16% 9% 1	3281
	21st to end	Night	65% 5% 11% 14% 5%	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	17% 17% 36% 23% 6% 1	270
	11th to 20th	Day	15% 21% 35% 23% 6%	270
	21st to end	Day	22% 12% 40% 21% 4 1	297
February	1st to 10th	Day	14% 22% 41% 17% 6% 1	270
	11th to 20th	Day	20% 25% 34% 16% 5%	270
	21st to end	Day	21% 24% 41% 13% 1	225
March	1st to 10th	Day	18% 26% 42% 11% 3	270
	11th to 20th	Day	23% 19% 33% 17% 6% 2	290
	21st to end	Day	27% 12% 32% 22% 6% 1	506
April	1st to 10th	Day	27% 12% 34% 20% 6%	428
	11th to 20th	Day	22% 21% 28% 17% 11% 2	412
	21st to end	Day	23% 13% 28% 23% 12% 1	420
May	1st to 10th	Day	21% 13% 34% 23% 8% 2	444
	11th to 20th	Day	17% 12% 33% 24% 11% 3	625
	21st to end	Day	16% 11% 28% 26% 14% 6%	679
June	1st to 10th	Day	10% 8% 33% 32% 12% 5%	630
	11th to 20th	Day	13% 9% 30% 29% 14% 4	630
	21st to end	Day	12% 7% 32% 32% 12% 5%	630
July	1st to 10th	Day	8% 5% 22% 31% 26% 9%	621
	11th to 20th	Day	9% 7% 29% 30% 20% 6%	618
	21st to end	Day	5% 4 32% 32% 20% 6%	684
August	1st to 10th	Day	8% 3 25% 35% 19% 9%	626
	11th to 20th	Day	14% 4 15% 30% 24% 13%	447
	21st to end	Day	13% 7% 23% 28% 21% 9%	495
September	1st to 10th	Day	13% 7% 25% 28% 18% 8%	450
	11th to 20th	Day	12% 5% 20% 34% 21% 9%	450
	21st to end	Day	18% 13% 26% 22% 17% 5%	450
October	1st to 10th	Day	19% 11% 25% 26% 15% 4	378
	11th to 20th	Day	21% 21% 33% 17% 7%	270
	21st to end	Day	26% 14% 39% 15% 5% 1	297
November	1st to 10th	Day	17% 18% 34% 21% 9% 2	270
	11th to 20th	Day	16% 20% 40% 18% 6%	270
	21st to end	Day	23% 16% 39% 17% 6%	270
December	1st to 10th	Day	20% 18% 41% 15% 4 1	270
	11th to 20th	Day	22% 20% 37% 13% 6% 1	270
	21st to end	Day	25% 20% 35% 18% 1 1	297
January	1st to 10th	Night	17% 17% 38% 22% 6%	950
	11th to 20th	Night	20% 14% 38% 21% 6% 1	950
	21st to end	Night	19% 13% 38% 25% 6%	1045
February	1st to 10th	Night	19% 15% 36% 24% 5% 1	950
	11th to 20th	Night	15% 17% 37% 24% 5%	757
	21st to end	Night	24% 14% 38% 19% 4	628
March	1st to 10th	Night	20% 13% 35% 24% 8% 1	760
	11th to 20th	Night	15% 14% 39% 25% 7%	737
	21st to end	Night	21% 9% 30% 32% 7% 1	627
April	1st to 10th	Night	22% 12% 37% 23% 7%	546
	11th to 20th	Night	23% 10% 34% 25% 7% 1	533
	21st to end	Night	21% 9% 31% 29% 10% 1	540
May	1st to 10th	Night	19% 9% 34% 32% 6% 1	540
	11th to 20th	Night	18% 8% 30% 31% 12% 1	531
	21st to end	Night	15% 5% 25% 35% 18% 2	584
June	1st to 10th	Night	11% 5% 27% 39% 17% 1	540
	11th to 20th	Night	14% 5% 30% 36% 14% 2	540
	21st to end	Night	10% 5% 24% 43% 17% 1	540
July	1st to 10th	Night	8% 1 19% 41% 28% 3	525
	11th to 20th	Night	7% 2 25% 39% 25% 2	522
	21st to end	Night	6% 3 24% 41% 25% 1	591
August	1st to 10th	Night	7% 2 16% 45% 26% 4	537
	11th to 20th	Night	8% 2 16% 40% 27% 6%	534
	21st to end	Night	10% 2 20% 40% 24% 3	594
September	1st to 10th	Night	11% 4 23% 34% 24% 6%	540
	11th to 20th	Night	12% 4 22% 32% 23% 6%	625
	21st to end	Night	15% 9% 25% 27% 20% 3	720
October	1st to 10th	Night	15% 8% 28% 30% 18% 2	720
	11th to 20th	Night	20% 13% 33% 26% 8% 1	720
	21st to end	Night	22% 11% 33% 25% 9% 1	792
November	1st to 10th	Night	15% 12% 38% 24% 10% 1	740
	11th to 20th	Night	21% 18% 33% 22% 6%	760
	21st to end	Night	21% 13% 36% 22% 7%	909
December	1st to 10th	Night	20% 16% 37% 22% 5%	950
	11th to 20th	Night	22% 14% 39% 19% 5% 1	950
	21st to end	Night	27% 15% 36% 20% 3	1045

Page generated at 2024-03-31 05:08:53. Version ac07

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