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 2024-11-04.

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% 4 9% 5% 4 5% 4 5% 7% 32%	101609
	Night	13% 12% 4 10% 5% 4 4 4 5% 6% 33%	97513
Transparency	Day	50% 6% 13% 21% 10% 1	105127
	Night	50% 6% 12% 21% 10% 1	102135
Seeing	Day	20% 17% 34% 20% 8% 2	16079
	Night	19% 14% 34% 24% 8% 1	25940

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	11% 17% 8% 21% 6% 4 4 3 4 5% 16%	2527
	11th to 20th	Day	7% 15% 7% 16% 11% 8% 9% 5% 7% 5% 11%	2530
	21st to end	Day	9% 18% 11% 19% 6% 5% 5% 2 4 5% 15%	2856
February	1st to 10th	Day	8% 14% 5% 13% 7% 5% 5% 5% 5% 5% 28%	1710
	11th to 20th	Day	8% 13% 5% 13% 7% 6% 5% 5% 4 5% 28%	1664
	21st to end	Day	12% 13% 7% 12% 8% 5% 4 4 5% 6% 26%	1560
March	1st to 10th	Day	10% 11% 3 11% 6% 5% 4 3 5% 6% 36%	3120
	11th to 20th	Day	8% 13% 4 13% 6% 4 4 4 6% 8% 30%	3475
	21st to end	Day	18% 15% 4 14% 5% 3 4 3 4 5% 24%	4027
April	1st to 10th	Day	15% 16% 5% 10% 5% 4 3 4 5% 5% 28%	2280
	11th to 20th	Day	20% 14% 5% 9% 4 4 4 2 4 5% 30%	2254
	21st to end	Day	20% 13% 3 8% 6% 4 4 3 4 5% 31%	2437
May	1st to 10th	Day	18% 9% 3 6% 4 4 4 3 5% 6% 39%	4399
	11th to 20th	Day	16% 8% 2 6% 4 5% 5% 4 6% 7% 37%	4399
	21st to end	Day	19% 9% 3 7% 5% 4 4 3 6% 7% 33%	4824
June	1st to 10th	Day	14% 6% 2 6% 6% 5% 5% 4 6% 8% 39%	2660
	11th to 20th	Day	15% 8% 3 7% 5% 5% 5% 4 6% 7% 36%	2660
	21st to end	Day	14% 6% 2 6% 5% 5% 5% 5% 7% 8% 36%	2660
July	1st to 10th	Day	13% 5% 2 6% 5% 5% 5% 5% 7% 9% 39%	4440
	11th to 20th	Day	8% 4 2 5% 4 4 5% 4 7% 10% 45%	4440
	21st to end	Day	8% 7% 2 6% 4 4 5% 4 7% 8% 46%	4813
August	1st to 10th	Day	14% 7% 2 7% 4 5% 5% 4 6% 8% 37%	4398
	11th to 20th	Day	15% 5% 2 5% 3 4 4 3 5% 8% 46%	4041
	21st to end	Day	15% 8% 3 6% 5% 5% 4 4 5% 7% 38%	4189
September	1st to 10th	Day	14% 7% 2 6% 5% 4 4 3 6% 8% 41%	2280
	11th to 20th	Day	15% 7% 2 6% 4 5% 4 4 6% 8% 40%	2280
	21st to end	Day	20% 9% 2 6% 4 3 3 4 4 6% 38%	2025
October	1st to 10th	Day	18% 11% 3 6% 3 4 5% 3 6% 7% 35%	1900
	11th to 20th	Day	19% 16% 4 10% 4 3 4 3 4 5% 27%	1900
	21st to end	Day	21% 16% 4 6% 4 4 4 3 5% 4 28%	1924
November	1st to 10th	Day	14% 19% 4 8% 5% 3 4 4 4 6% 30%	1676
	11th to 20th	Day	15% 18% 10% 13% 8% 3 4 2 4 4 19%	1520
	21st to end	Day	14% 15% 5% 14% 8% 5% 5% 3 5% 5% 21%	1520
December	1st to 10th	Day	11% 16% 9% 16% 8% 6% 5% 3 4 4 16%	1520
	11th to 20th	Day	11% 16% 7% 12% 13% 7% 7% 4 4 3 16%	1918
	21st to end	Day	21% 24% 7% 16% 5% 4 4 1 2 4 13%	2783
January	1st to 10th	Night	11% 14% 7% 19% 7% 5% 5% 3 4 5% 20%	4428
	11th to 20th	Night	8% 14% 6% 18% 9% 8% 8% 5% 6% 5% 14%	4440
	21st to end	Night	9% 20% 10% 18% 6% 5% 4 3 5% 4 17%	4807
February	1st to 10th	Night	7% 14% 5% 13% 7% 6% 5% 4 5% 6% 27%	2470
	11th to 20th	Night	8% 11% 4 10% 7% 7% 7% 5% 5% 5% 29%	2403
	21st to end	Night	12% 15% 4 10% 6% 6% 5% 3 5% 5% 28%	1893
March	1st to 10th	Night	9% 8% 3 7% 4 4 5% 4 6% 9% 40%	3733
	11th to 20th	Night	9% 10% 5% 16% 6% 4 4 4 5% 6% 32%	3513
	21st to end	Night	20% 16% 5% 11% 5% 4 3 3 4 4 27%	3603
April	1st to 10th	Night	18% 15% 3 7% 5% 4 4 4 6% 5% 29%	1900
	11th to 20th	Night	21% 11% 5% 7% 4 3 4 4 4 6% 32%	1875
	21st to end	Night	20% 12% 3 6% 4 3 3 3 6% 6% 34%	1739
May	1st to 10th	Night	16% 10% 3 7% 5% 4 4 4 4 7% 37%	2506
	11th to 20th	Night	14% 7% 3 6% 3 4 3 3 4 7% 46%	2506
	21st to end	Night	14% 9% 3 8% 5% 4 5% 4 5% 7% 35%	2743
June	1st to 10th	Night	12% 6% 2 6% 4 4 4 5% 5% 8% 44%	1520
	11th to 20th	Night	11% 6% 2 7% 6% 5% 5% 5% 6% 7% 39%	1520
	21st to end	Night	11% 6% 3 5% 4 5% 5% 4 6% 9% 42%	1520
July	1st to 10th	Night	10% 5% 2 5% 4 4 3 4 5% 8% 49%	2530
	11th to 20th	Night	7% 4 2 5% 3 3 3 3 6% 9% 55%	2530
	21st to end	Night	8% 6% 2 5% 3 3 3 4 6% 7% 53%	2750
August	1st to 10th	Night	12% 6% 2 6% 4 5% 4 4 6% 9% 43%	2539
	11th to 20th	Night	13% 6% 2 4 2 3 3 3 4 8% 51%	2798
	21st to end	Night	17% 9% 2 5% 4 3 3 3 5% 7% 43%	3466
September	1st to 10th	Night	10% 5% 2 5% 4 4 4 3 6% 7% 50%	1900
	11th to 20th	Night	10% 6% 2 4 4 4 5% 4 5% 7% 49%	1900
	21st to end	Night	16% 7% 2 6% 4 4 4 3 5% 7% 41%	2133
October	1st to 10th	Night	16% 9% 2 6% 3 4 3 3 5% 5% 43%	2280
	11th to 20th	Night	16% 14% 4 7% 5% 4 4 4 5% 6% 32%	2280
	21st to end	Night	19% 15% 4 7% 5% 4 4 4 4 5% 29%	2674
November	1st to 10th	Night	14% 14% 4 8% 5% 4 3 3 5% 6% 32%	2471
	11th to 20th	Night	13% 15% 6% 12% 5% 5% 4 3 5% 5% 25%	2660
	21st to end	Night	14% 14% 6% 12% 6% 5% 4 4 5% 6% 25%	2660
December	1st to 10th	Night	10% 16% 8% 16% 8% 5% 5% 5% 4 4 19%	2660
	11th to 20th	Night	11% 16% 6% 15% 9% 6% 5% 4 6% 5% 19%	3279
	21st to end	Night	23% 23% 6% 11% 5% 5% 3 2 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	47% 7% 14% 19% 13% 1	3120
	11th to 20th	Day	50% 7% 13% 20% 10% 1	3475
	21st to end	Day	61% 6% 9% 18% 5% 1	4027
April	1st to 10th	Day	56% 6% 10% 16% 10% 1	2280
	11th to 20th	Day	57% 4 9% 20% 8% 2	2254
	21st to end	Day	56% 5% 9% 18% 11% 1	2437
May	1st to 10th	Day	45% 8% 11% 22% 13% 2	4440
	11th to 20th	Day	42% 8% 14% 25% 10% 1	4403
	21st to end	Day	49% 7% 11% 18% 14% 1	4837
June	1st to 10th	Day	40% 9% 14% 26% 11% 1	2660
	11th to 20th	Day	46% 7% 12% 21% 14% 1	2660
	21st to end	Day	42% 8% 17% 24% 9% 1	2660
July	1st to 10th	Day	39% 6% 18% 25% 11% 1	4371
	11th to 20th	Day	31% 7% 17% 32% 12% 1	4365
	21st to end	Day	34% 7% 13% 31% 15%	4662
August	1st to 10th	Day	43% 6% 16% 23% 11% 1	4383
	11th to 20th	Day	36% 6% 17% 30% 10%	4080
	21st to end	Day	44% 5% 16% 23% 10% 1	4188
September	1st to 10th	Day	39% 6% 16% 28% 11%	2280
	11th to 20th	Day	41% 7% 18% 26% 7%	2280
	21st to end	Day	47% 7% 12% 26% 8%	2025
October	1st to 10th	Day	37% 4 14% 29% 15% 1	3160
	11th to 20th	Day	53% 4 8% 23% 11%	3140
	21st to end	Day	52% 5% 16% 20% 6%	3149
November	1st to 10th	Day	55% 6% 12% 19% 8% 1	1676
	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	38% 8% 18% 21% 14% 1	3733
	11th to 20th	Night	50% 7% 12% 22% 8% 1	3513
	21st to end	Night	62% 5% 7% 16% 9% 1	3603
April	1st to 10th	Night	54% 7% 8% 17% 13% 1	1900
	11th to 20th	Night	53% 5% 9% 19% 11% 2	1875
	21st to end	Night	50% 5% 9% 23% 12% 1	1739
May	1st to 10th	Night	44% 8% 15% 19% 13%	2530
	11th to 20th	Night	37% 7% 10% 27% 17% 3	2507
	21st to end	Night	44% 10% 13% 19% 12% 1	2751
June	1st to 10th	Night	37% 8% 16% 27% 12% 1	1520
	11th to 20th	Night	40% 8% 14% 20% 17% 2	1520
	21st to end	Night	37% 8% 15% 25% 13% 1	1520
July	1st to 10th	Night	33% 6% 20% 26% 12% 3	2490
	11th to 20th	Night	25% 7% 15% 40% 13% 1	2482
	21st to end	Night	29% 6% 13% 30% 21% 1	2662
August	1st to 10th	Night	38% 6% 15% 26% 14% 2	2530
	11th to 20th	Night	33% 5% 16% 35% 10% 1	2825
	21st to end	Night	41% 5% 16% 26% 10% 2	3466
September	1st to 10th	Night	32% 6% 16% 32% 13% 1	1900
	11th to 20th	Night	33% 7% 18% 33% 9%	1900
	21st to end	Night	42% 6% 15% 27% 9% 1	2133
October	1st to 10th	Night	31% 4 9% 33% 21% 2	3800
	11th to 20th	Night	46% 5% 11% 22% 15% 1	3779
	21st to end	Night	56% 5% 11% 20% 8%	4399
November	1st to 10th	Night	52% 6% 13% 20% 9%	2471
	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	24% 21% 36% 13% 5%	460
	11th to 20th	Day	30% 18% 29% 18% 4 1	452
	21st to end	Day	28% 18% 29% 19% 6% 1	548
May	1st to 10th	Day	23% 21% 32% 17% 5% 1	653
	11th to 20th	Day	21% 18% 31% 21% 6% 3	675
	21st to end	Day	23% 15% 34% 19% 8% 1	734
June	1st to 10th	Day	14% 18% 35% 24% 7% 2	680
	11th to 20th	Day	18% 16% 39% 19% 6% 2	680
	21st to end	Day	18% 12% 37% 19% 11% 3	680
July	1st to 10th	Day	10% 9% 35% 25% 15% 5%	671
	11th to 20th	Day	11% 12% 33% 27% 11% 5%	668
	21st to end	Day	9% 10% 37% 23% 15% 5%	739
August	1st to 10th	Day	14% 8% 32% 29% 14% 3	676
	11th to 20th	Day	16% 7% 28% 31% 14% 4	665
	21st to end	Day	18% 12% 28% 25% 14% 3	548
September	1st to 10th	Day	17% 13% 30% 26% 11% 3	490
	11th to 20th	Day	15% 12% 32% 30% 9% 2	490
	21st to end	Day	24% 16% 29% 18% 11% 2	422
October	1st to 10th	Day	26% 19% 28% 18% 9% 1	300
	11th to 20th	Day	28% 25% 34% 11% 3	300
	21st to end	Day	32% 25% 35% 8% 1	330
November	1st to 10th	Day	24% 20% 38% 15% 3	279
	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	24% 16% 34% 20% 5% 1	570
	11th to 20th	Night	28% 10% 31% 23% 8%	563
	21st to end	Night	25% 12% 31% 25% 7% 1	570
May	1st to 10th	Night	22% 13% 33% 25% 5% 1	570
	11th to 20th	Night	20% 11% 34% 27% 7% 2	561
	21st to end	Night	17% 9% 32% 32% 9% 1	617
June	1st to 10th	Night	15% 8% 33% 33% 11%	570
	11th to 20th	Night	14% 9% 34% 34% 9%	570
	21st to end	Night	14% 8% 31% 35% 11% 2	570
July	1st to 10th	Night	8% 5% 30% 36% 21% 1	555
	11th to 20th	Night	11% 6% 33% 31% 19% 1	552
	21st to end	Night	8% 4 28% 40% 18% 2	624
August	1st to 10th	Night	11% 4 25% 42% 17% 1	567
	11th to 20th	Night	14% 5% 24% 34% 21% 2	564
	21st to end	Night	17% 7% 27% 28% 19% 2	627
September	1st to 10th	Night	12% 8% 26% 36% 14% 3	570
	11th to 20th	Night	12% 8% 34% 30% 15% 2	570
	21st to end	Night	20% 13% 30% 25% 11% 1	737
October	1st to 10th	Night	22% 13% 29% 24% 11% 1	760
	11th to 20th	Night	26% 16% 34% 17% 6% 1	760
	21st to end	Night	27% 14% 30% 23% 6%	836
November	1st to 10th	Night	24% 14% 37% 20% 5% 1	774
	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 2024-11-01 21:47:42. Version ac07

Copyright © 2024 Attilla Danko.