Chequamegon National Forest
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chequamegon National Forest 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	14% 11% 5% 8% 7% 3 5% 5% 5% 7% 31%	78701
	Night	13% 12% 5% 9% 6% 3 5% 5% 5% 6% 31%	81482
Transparency	Day	52% 7% 12% 20% 9% 1	78401
	Night	53% 6% 12% 19% 9% 1	81302
Seeing	Day	19% 17% 34% 20% 8% 2	15140
	Night	19% 14% 34% 24% 8% 1	25249

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% 16% 9% 19% 7% 3 4 4 4 5% 16%	2527
	11th to 20th	Day	8% 14% 8% 14% 13% 6% 10% 6% 6% 5% 11%	2530
	21st to end	Day	9% 17% 12% 17% 8% 4 5% 4 4 5% 15%	2856
February	1st to 10th	Day	9% 14% 5% 11% 8% 4 5% 5% 6% 5% 28%	1710
	11th to 20th	Day	8% 13% 5% 11% 8% 5% 5% 6% 4 6% 29%	1664
	21st to end	Day	12% 11% 8% 12% 8% 4 4 5% 5% 6% 26%	1560
March	1st to 10th	Day	12% 12% 5% 9% 8% 4 4 4 5% 6% 31%	1900
	11th to 20th	Day	12% 12% 5% 9% 7% 3 3 4 5% 6% 33%	2085
	21st to end	Day	15% 14% 6% 8% 7% 3 4 4 5% 7% 28%	2422
April	1st to 10th	Day	16% 14% 6% 10% 6% 3 4 4 5% 5% 28%	2184
	11th to 20th	Day	20% 13% 6% 8% 5% 2 3 3 4 5% 30%	2134
	21st to end	Day	20% 12% 4 7% 6% 3 5% 4 4 5% 31%	2308
May	1st to 10th	Day	18% 9% 4 6% 5% 4 5% 4 5% 6% 33%	2520
	11th to 20th	Day	17% 9% 3 6% 5% 3 6% 5% 5% 7% 33%	2479
	21st to end	Day	16% 8% 2 4 6% 3 5% 5% 7% 9% 35%	2725
June	1st to 10th	Day	14% 5% 2 5% 6% 3 6% 5% 6% 8% 39%	2520
	11th to 20th	Day	14% 7% 3 7% 6% 3 5% 5% 6% 7% 37%	2520
	21st to end	Day	14% 6% 2 5% 6% 3 6% 6% 7% 9% 36%	2520
July	1st to 10th	Day	8% 3 2 5% 5% 3 6% 6% 6% 10% 46%	2520
	11th to 20th	Day	12% 5% 2 5% 5% 3 5% 5% 6% 9% 42%	2520
	21st to end	Day	9% 5% 2 5% 5% 3 5% 6% 7% 8% 45%	2743
August	1st to 10th	Day	12% 6% 2 5% 6% 4 5% 6% 7% 8% 38%	2496
	11th to 20th	Day	15% 6% 2 5% 5% 3 4 4 5% 8% 43%	2301
	21st to end	Day	14% 6% 3 5% 5% 3 4 4 5% 7% 43%	2385
September	1st to 10th	Day	15% 7% 3 5% 6% 3 4 4 6% 8% 39%	2160
	11th to 20th	Day	15% 7% 2 5% 5% 3 4 5% 6% 8% 39%	2160
	21st to end	Day	21% 9% 3 6% 5% 2 4 4 4 6% 35%	1919
October	1st to 10th	Day	19% 11% 3 6% 4 3 5% 4 5% 7% 33%	1800
	11th to 20th	Day	20% 16% 4 9% 6% 3 4 4 4 5% 26%	1800
	21st to end	Day	22% 16% 5% 5% 5% 3 4 4 4 4 27%	1823
November	1st to 10th	Day	14% 18% 5% 7% 6% 3 4 5% 4 6% 30%	1649
	11th to 20th	Day	15% 16% 11% 12% 9% 2 5% 3 4 4 19%	1520
	21st to end	Day	15% 13% 7% 12% 9% 4 6% 4 4 5% 21%	1520
December	1st to 10th	Day	12% 15% 10% 14% 11% 3 7% 4 4 4 16%	1520
	11th to 20th	Day	12% 14% 8% 11% 14% 5% 7% 5% 4 3 16%	1918
	21st to end	Day	21% 22% 8% 14% 7% 3 4 2 2 3 13%	2783
January	1st to 10th	Night	11% 13% 8% 16% 10% 4 4 5% 4 5% 20%	4428
	11th to 20th	Night	8% 13% 6% 17% 11% 6% 8% 7% 6% 5% 14%	4440
	21st to end	Night	9% 19% 10% 16% 7% 3 4 4 5% 4 17%	4807
February	1st to 10th	Night	8% 12% 6% 12% 8% 4 6% 5% 5% 6% 27%	2470
	11th to 20th	Night	8% 10% 5% 10% 7% 5% 8% 6% 5% 6% 29%	2403
	21st to end	Night	12% 14% 5% 9% 7% 4 6% 4 5% 6% 29%	1893
March	1st to 10th	Night	13% 10% 4 8% 6% 4 4 5% 5% 8% 35%	2280
	11th to 20th	Night	11% 10% 5% 7% 5% 3 4 5% 4 6% 39%	2110
	21st to end	Night	16% 13% 4 8% 6% 2 4 4 4 5% 33%	2175
April	1st to 10th	Night	18% 13% 4 7% 6% 3 5% 5% 6% 6% 29%	1820
	11th to 20th	Night	21% 11% 5% 6% 4 3 4 4 4 6% 32%	1775
	21st to end	Night	20% 11% 3 6% 4 3 4 3 6% 6% 34%	1648
May	1st to 10th	Night	17% 11% 4 7% 6% 4 5% 5% 5% 6% 32%	1440
	11th to 20th	Night	17% 8% 3 6% 4 2 4 3 5% 8% 38%	1416
	21st to end	Night	13% 7% 3 6% 6% 4 4 5% 5% 8% 38%	1551
June	1st to 10th	Night	12% 5% 3 5% 4 2 5% 5% 4 8% 45%	1440
	11th to 20th	Night	11% 6% 3 6% 6% 4 5% 6% 6% 7% 40%	1440
	21st to end	Night	10% 6% 3 4 5% 4 6% 5% 6% 9% 42%	1440
July	1st to 10th	Night	6% 4 1 4 5% 3 4 4 6% 10% 51%	1440
	11th to 20th	Night	10% 4 2 6% 4 3 4 5% 6% 9% 46%	1440
	21st to end	Night	6% 3 2 4 5% 3 4 5% 6% 9% 53%	1575
August	1st to 10th	Night	10% 4 2 4 4 3 4 4 6% 9% 50%	1440
	11th to 20th	Night	13% 6% 3 5% 3 2 4 4 5% 7% 49%	1600
	21st to end	Night	14% 6% 2 5% 4 2 3 3 5% 7% 49%	1970
September	1st to 10th	Night	11% 5% 2 4 4 3 4 5% 6% 7% 50%	1800
	11th to 20th	Night	10% 6% 2 4 5% 2 5% 4 6% 7% 49%	1800
	21st to end	Night	17% 7% 3 5% 5% 3 4 4 6% 8% 39%	2020
October	1st to 10th	Night	17% 9% 3 5% 4 4 3 4 4 5% 41%	2160
	11th to 20th	Night	17% 14% 4 6% 6% 3 4 5% 5% 6% 32%	2160
	21st to end	Night	18% 15% 4 6% 6% 3 4 5% 4 6% 29%	2533
November	1st to 10th	Night	15% 13% 5% 7% 6% 3 4 3 5% 7% 33%	2425
	11th to 20th	Night	14% 13% 8% 11% 7% 4 4 4 5% 5% 25%	2660
	21st to end	Night	14% 13% 6% 11% 7% 4 5% 5% 5% 6% 25%	2660
December	1st to 10th	Night	10% 15% 8% 15% 9% 4 6% 6% 4 4 19%	2660
	11th to 20th	Night	12% 14% 6% 13% 10% 5% 5% 5% 5% 5% 19%	3279
	21st to end	Night	23% 22% 6% 10% 6% 3 4 3 3 3 16%	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	69% 5% 7% 15% 4	2528
	11th to 20th	Day	73% 6% 7% 11% 4	2530
	21st to end	Day	70% 5% 10% 11% 4	2856
February	1st to 10th	Day	56% 5% 10% 18% 11% 1	1710
	11th to 20th	Day	54% 8% 10% 21% 7%	1673
	21st to end	Day	59% 5% 10% 16% 9% 1	1560
March	1st to 10th	Day	53% 6% 14% 17% 9% 1	1900
	11th to 20th	Day	52% 6% 12% 20% 10% 1	2085
	21st to end	Day	57% 6% 10% 18% 7% 1	2422
April	1st to 10th	Day	57% 6% 10% 16% 10% 1	2184
	11th to 20th	Day	58% 4 9% 20% 8% 2	2134
	21st to end	Day	57% 5% 9% 18% 10% 1	2308
May	1st to 10th	Day	50% 8% 12% 21% 9% 1	2520
	11th to 20th	Day	49% 6% 13% 21% 9% 1	2483
	21st to end	Day	45% 7% 12% 22% 12% 1	2725
June	1st to 10th	Day	40% 9% 14% 26% 11% 1	2520
	11th to 20th	Day	45% 7% 13% 21% 14% 1	2520
	21st to end	Day	42% 9% 17% 23% 9% 1	2520
July	1st to 10th	Day	30% 8% 17% 30% 14%	2451
	11th to 20th	Day	36% 9% 13% 26% 14% 2	2445
	21st to end	Day	33% 10% 16% 25% 16% 1	2591
August	1st to 10th	Day	39% 9% 16% 26% 9% 2	2481
	11th to 20th	Day	40% 7% 17% 24% 11%	2301
	21st to end	Day	39% 7% 14% 26% 13% 1	2385
September	1st to 10th	Day	41% 6% 15% 27% 11%	2160
	11th to 20th	Day	42% 7% 18% 26% 7%	2160
	21st to end	Day	49% 7% 13% 24% 6%	1919
October	1st to 10th	Day	49% 7% 13% 24% 7% 1	1800
	11th to 20th	Day	60% 5% 10% 17% 7%	1800
	21st to end	Day	59% 7% 11% 16% 7%	1823
November	1st to 10th	Day	55% 6% 12% 19% 8% 1	1649
	11th to 20th	Day	69% 5% 10% 12% 5% 1	1520
	21st to end	Day	64% 7% 12% 13% 4 1	1520
December	1st to 10th	Day	70% 7% 10% 10% 3	1520
	11th to 20th	Day	70% 6% 10% 10% 3	1915
	21st to end	Day	78% 4 5% 10% 3	2783
January	1st to 10th	Night	66% 6% 10% 15% 4	4428
	11th to 20th	Night	68% 7% 11% 11% 3	4440
	21st to end	Night	69% 5% 7% 15% 3	4807
February	1st to 10th	Night	56% 5% 9% 18% 12% 1	2470
	11th to 20th	Night	53% 7% 12% 19% 9% 1	2404
	21st to end	Night	55% 6% 11% 18% 8% 2	1893
March	1st to 10th	Night	48% 6% 14% 19% 12% 1	2280
	11th to 20th	Night	47% 5% 14% 22% 11% 1	2110
	21st to end	Night	54% 5% 11% 18% 11% 1	2175
April	1st to 10th	Night	54% 7% 8% 17% 13% 1	1820
	11th to 20th	Night	54% 5% 9% 18% 11% 2	1775
	21st to end	Night	51% 5% 10% 22% 12% 1	1648
May	1st to 10th	Night	51% 8% 13% 19% 9% 1	1440
	11th to 20th	Night	45% 6% 11% 24% 13% 2	1417
	21st to end	Night	43% 9% 13% 21% 13% 1	1552
June	1st to 10th	Night	36% 8% 16% 27% 12% 1	1440
	11th to 20th	Night	39% 8% 14% 20% 17% 2	1440
	21st to end	Night	36% 9% 16% 25% 13% 1	1440
July	1st to 10th	Night	27% 8% 16% 32% 17% 1	1400
	11th to 20th	Night	32% 9% 14% 27% 15% 2	1392
	21st to end	Night	26% 9% 16% 31% 17% 2	1487
August	1st to 10th	Night	30% 8% 16% 32% 11% 3	1431
	11th to 20th	Night	35% 8% 14% 28% 14% 2	1600
	21st to end	Night	35% 6% 14% 27% 15% 3	1970
September	1st to 10th	Night	33% 6% 16% 31% 14% 1	1800
	11th to 20th	Night	33% 7% 18% 33% 9%	1800
	21st to end	Night	44% 6% 15% 26% 8%	2020
October	1st to 10th	Night	44% 6% 13% 27% 10% 1	2160
	11th to 20th	Night	51% 6% 14% 19% 8% 1	2160
	21st to end	Night	56% 7% 12% 17% 7%	2533
November	1st to 10th	Night	52% 6% 12% 21% 9%	2425
	11th to 20th	Night	60% 6% 14% 12% 8%	2660
	21st to end	Night	59% 6% 14% 15% 4 1	2660
December	1st to 10th	Night	66% 7% 10% 14% 3	2660
	11th to 20th	Night	65% 7% 10% 14% 3	3281
	21st to end	Night	74% 4 6% 11% 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	19% 21% 34% 19% 5% 2	270
	11th to 20th	Day	21% 20% 35% 21% 2	270
	21st to end	Day	19% 18% 39% 22% 2	297
February	1st to 10th	Day	19% 27% 37% 12% 4	270
	11th to 20th	Day	17% 33% 36% 10% 4	270
	21st to end	Day	22% 27% 43% 7%	225
March	1st to 10th	Day	17% 23% 42% 14% 4	270
	11th to 20th	Day	19% 23% 39% 14% 4 1	270
	21st to end	Day	22% 21% 35% 16% 4 3	420
April	1st to 10th	Day	23% 21% 36% 14% 6%	428
	11th to 20th	Day	30% 17% 28% 19% 5% 1	412
	21st to end	Day	27% 19% 29% 19% 5% 1	503
May	1st to 10th	Day	23% 21% 33% 17% 5% 1	603
	11th to 20th	Day	22% 17% 31% 21% 6% 3	625
	21st to end	Day	23% 14% 34% 19% 9% 1	679
June	1st to 10th	Day	13% 18% 35% 25% 8% 2	630
	11th to 20th	Day	16% 16% 40% 20% 6% 2	630
	21st to end	Day	17% 12% 37% 20% 12% 3	630
July	1st to 10th	Day	9% 9% 35% 26% 16% 5%	621
	11th to 20th	Day	12% 12% 33% 27% 10% 5%	618
	21st to end	Day	10% 10% 38% 23% 15% 5%	684
August	1st to 10th	Day	14% 8% 32% 29% 14% 3	626
	11th to 20th	Day	16% 7% 27% 31% 15% 4	615
	21st to end	Day	18% 12% 27% 25% 14% 3	504
September	1st to 10th	Day	18% 13% 29% 27% 11% 3	450
	11th to 20th	Day	16% 12% 32% 29% 9% 2	450
	21st to end	Day	26% 16% 30% 17% 9% 2	386
October	1st to 10th	Day	26% 18% 26% 19% 9% 1	270
	11th to 20th	Day	28% 25% 33% 11% 3	270
	21st to end	Day	32% 24% 36% 7% 1	297
November	1st to 10th	Day	23% 21% 38% 16% 3	270
	11th to 20th	Day	27% 25% 37% 9% 3	270
	21st to end	Day	23% 24% 39% 11% 2	270
December	1st to 10th	Day	19% 19% 42% 16% 3	270
	11th to 20th	Day	24% 25% 36% 12% 2	270
	21st to end	Day	25% 23% 39% 9% 3	297
January	1st to 10th	Night	15% 20% 39% 20% 5%	950
	11th to 20th	Night	20% 16% 40% 18% 6% 1	950
	21st to end	Night	19% 16% 40% 21% 4	1045
February	1st to 10th	Night	15% 19% 38% 22% 6%	950
	11th to 20th	Night	14% 22% 39% 18% 7% 1	929
	21st to end	Night	19% 17% 41% 21% 3	637
March	1st to 10th	Night	18% 17% 38% 21% 5% 1	760
	11th to 20th	Night	17% 19% 37% 20% 7% 1	590
	21st to end	Night	23% 14% 30% 21% 10% 2	627
April	1st to 10th	Night	23% 16% 34% 21% 5% 1	546
	11th to 20th	Night	29% 10% 29% 24% 8%	533
	21st to end	Night	25% 12% 31% 24% 7% 1	540
May	1st to 10th	Night	22% 13% 33% 25% 5% 1	540
	11th to 20th	Night	21% 10% 33% 27% 7% 2	531
	21st to end	Night	17% 9% 31% 32% 10% 1	584
June	1st to 10th	Night	14% 8% 33% 34% 11%	540
	11th to 20th	Night	14% 9% 34% 34% 10%	540
	21st to end	Night	13% 7% 31% 36% 12% 2	540
July	1st to 10th	Night	7% 5% 31% 35% 21% 1	525
	11th to 20th	Night	12% 6% 34% 30% 17% 1	522
	21st to end	Night	8% 4 29% 39% 18% 2	591
August	1st to 10th	Night	11% 4 24% 43% 18% 1	537
	11th to 20th	Night	14% 5% 23% 34% 21% 2	534
	21st to end	Night	16% 7% 28% 28% 19% 2	594
September	1st to 10th	Night	12% 8% 27% 35% 14% 3	540
	11th to 20th	Night	12% 8% 34% 30% 15% 2	540
	21st to end	Night	20% 13% 31% 24% 9% 1	698
October	1st to 10th	Night	23% 13% 29% 23% 11% 1	720
	11th to 20th	Night	26% 17% 33% 18% 6% 1	720
	21st to end	Night	27% 14% 30% 23% 6%	792
November	1st to 10th	Night	24% 14% 36% 20% 5% 1	759
	11th to 20th	Night	21% 22% 34% 18% 5% 1	950
	21st to end	Night	22% 22% 34% 17% 4	950
December	1st to 10th	Night	17% 20% 39% 19% 4	950
	11th to 20th	Night	21% 20% 34% 20% 5% 1	950
	21st to end	Night	28% 18% 34% 15% 4	1045

Page generated at 2024-03-31 05:08:52. Version ac07

Copyright © 2024 Attilla Danko.