Madeline Island
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Madeline Island clear sky chart from 2005-11-05 to 2018-11-30.

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 TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(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

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
40%
17859
11%
51715
8%
17813
42%
17813
17%
38452

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
26%
975
4%
2716
2%
970
28%
970
9%
2318
January16th to endNight
25%
1040
6%
2902
2%
1040
28%
1040
9%
2473
February1st to 15thNight
31%
954
7%
2480
3%
950
33%
950
14%
1986
February16th to endNight
36%
755
11%
2121
5%
755
39%
755
16%
1636
March1st to 15thNight
42%
741
15%
2301
11%
741
46%
741
20%
1621
March16th to endNight
45%
624
17%
2194
16%
624
50%
624
19%
1474
April1st to 15thNight
41%
584
12%
1947
11%
584
45%
584
17%
1375
April16th to endNight
48%
579
15%
1791
14%
579
50%
579
21%
1242
May1st to 15thNight
42%
585
12%
1560
8%
585
44%
585
19%
1173
May16th to endNight
55%
610
12%
1626
7%
609
57%
609
25%
1144
June1st to 15thNight
57%
585
9%
1560
6%
585
58%
585
27%
1067
June16th to endNight
57%
585
9%
1560
6%
585
58%
585
25%
1105
July1st to 15thNight
70%
555
13%
1480
8%
555
71%
555
37%
926
July16th to endNight
68%
612
16%
1545
10%
579
69%
579
38%
940
August1st to 15thNight
72%
575
23%
1569
19%
572
73%
572
40%
917
August16th to endNight
60%
621
19%
1996
19%
621
63%
621
30%
1180
September1st to 15thNight
61%
585
20%
1950
21%
585
65%
585
29%
1152
September16th to endNight
50%
702
13%
2109
10%
702
53%
702
24%
1408
October1st to 15thNight
40%
780
16%
2340
11%
780
43%
780
22%
1616
October16th to endNight
29%
832
11%
2626
7%
832
35%
832
15%
1991
November1st to 15thNight
28%
915
11%
2761
8%
915
32%
915
13%
2142
November16th to endNight
23%
1050
7%
2939
6%
1050
25%
1050
9%
2513
December1st to 15thNight
13%
975
2%
2730
1%
975
15%
975
5%
2463
December16th to endNight
16%
1040
5%
2912
1%
1040
19%
1040
6%
2590

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 ForecastData
Points
Cloud CoverDay
14%8%47%5%35%45%7%35%
52598
Night
14%10%48%6%35%446%30%
51885
Cloud CoverDay
14%8%37%5%35%45%6%35%
52608
Night
15%10%48%6%35%445%30%
51890
Cloud CoverDay
14%8%47%5%34447%34%
52606
Night
15%10%48%6%35%446%29%
51890
TransparencyDay
48%6%13%21%8%
52283
Night
55%5%11%18%8%
51718
SeeingDay
18%217%32%23%5%
7785
Night
20%423%31%17%3
17861

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
10%11%8%12%11%7%8%34416%
1552
16th to endDay
10%11%5%12%11%5%8%5%5%6%16%
1671
February1st to 15thDay
8%10%410%8%5%9%6%46%25%
1710
16th to endDay
11%13%5%8%8%35%5%5%7%25%
1637
March1st to 15thDay
11%9%38%6%35%45%7%33%
1990
16th to endDay
16%8%47%5%33446%34%
2381
April1st to 15thDay
15%8%45%6%25%445%37%
2331
16th to endDay
20%9%34434436%35%
2443
May1st to 15thDay
18%6%25%425%46%6%36%
2721
16th to endDay
14%6%35%425%5%5%8%37%
2841
June1st to 15thDay
13%6%3442445%7%41%
2730
16th to endDay
13%425%5%35%5%5%9%39%
2730
July1st to 15thDay
8%42331446%9%51%
2730
16th to endDay
6%3133235%5%9%54%
2879
August1st to 15thDay
8%42442446%8%50%
2633
16th to endDay
11%424424347%49%
2558
September1st to 15thDay
11%5%25%32345%8%46%
2340
16th to endDay
19%7%245%2445%6%37%
2167
October1st to 15thDay
19%8%35%42445%6%33%
1950
16th to endDay
21%14%47%434445%26%
1950
November1st to 15thDay
17%14%5%9%6%2435%6%25%
1754
16th to endDay
17%14%8%14%10%345%45%13%
1676
December1st to 15thDay
14%17%8%18%11%6%42338%
1560
16th to endDay
17%17%10%14%8%5%6%4337%
1664
January1st to 15thNight
13%12%6%11%10%7%8%5%45%15%
2716
16th to endNight
13%12%7%13%9%5%7%45%5%14%
2902
February1st to 15thNight
8%13%5%9%8%6%8%6%5%5%22%
2480
16th to endNight
13%11%5%8%7%35%5%46%26%
2121
March1st to 15thNight
12%9%37%6%34446%35%
2288
16th to endNight
14%8%36%5%35%45%6%36%
2194
April1st to 15thNight
18%10%47%5%34345%32%
1947
16th to endNight
19%9%36%42445%6%33%
1791
May1st to 15thNight
20%7%36%7%34445%32%
1560
16th to endNight
14%5%26%5%35%5%6%6%37%
1624
June1st to 15thNight
15%6%25%5%25%5%6%8%36%
1560
16th to endNight
14%6%35%435%5%5%8%36%
1560
July1st to 15thNight
7%424425%45%8%49%
1560
16th to endNight
7%424415%47%8%48%
1641
August1st to 15thNight
8%31332446%7%53%
1578
16th to endNight
13%41442345%7%48%
1996
September1st to 15thNight
10%425%42445%8%47%
1950
16th to endNight
17%6%25%4245%47%38%
2109
October1st to 15thNight
21%8%35%422346%37%
2340
16th to endNight
22%11%46%5%24446%27%
2626
November1st to 15thNight
16%15%5%9%6%25%45%425%
2761
16th to endNight
18%16%8%14%7%24335%17%
2939
December1st to 15thNight
16%18%7%15%12%45%23310%
2730
16th to endNight
15%20%8%12%8%46%33411%
2912

Percentage Cloud Cover SW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
10%11%8%12%11%8%7%44415%
1552
16th to endDay
11%11%5%14%10%6%7%5%46%15%
1671
February1st to 15thDay
8%10%410%9%5%9%6%45%24%
1710
16th to endDay
11%13%6%8%8%36%5%5%6%24%
1637
March1st to 15thDay
11%8%38%6%36%45%7%33%
2000
16th to endDay
16%8%47%5%3445%5%34%
2381
April1st to 15thDay
16%7%46%5%34445%38%
2331
16th to endDay
20%9%35%434445%35%
2443
May1st to 15thDay
18%6%26%42446%7%36%
2721
16th to endDay
14%6%24425%5%6%8%37%
2841
June1st to 15thDay
14%6%25%42445%8%41%
2730
16th to endDay
13%5%245%25%46%8%39%
2730
July1st to 15thDay
9%31432345%10%51%
2730
16th to endDay
6%31332446%8%54%
2879
August1st to 15thDay
8%5%1442445%7%50%
2633
16th to endDay
11%424423447%49%
2558
September1st to 15thDay
11%6%24424448%47%
2340
16th to endDay
20%6%35%5%2345%6%37%
2167
October1st to 15thDay
20%9%35%4235%5%6%32%
1950
16th to endDay
20%15%46%5%33445%27%
1950
November1st to 15thDay
17%15%5%9%6%23445%25%
1754
16th to endDay
17%15%8%14%9%3444412%
1676
December1st to 15thDay
14%17%9%17%12%5%5%2229%
1560
16th to endDay
17%18%10%14%9%47%4336%
1664
January1st to 15thNight
13%12%6%11%11%7%9%5%3414%
2716
16th to endNight
12%12%7%13%10%5%7%5%5%413%
2902
February1st to 15thNight
9%13%5%9%9%5%8%6%4422%
2473
16th to endNight
12%12%5%8%8%35%5%5%5%26%
2121
March1st to 15thNight
12%9%47%6%3445%6%35%
2301
16th to endNight
15%8%36%5%3445%5%37%
2194
April1st to 15thNight
18%9%46%6%34445%32%
1947
16th to endNight
19%8%36%42445%6%33%
1791
May1st to 15thNight
20%7%46%5%345%35%32%
1559
16th to endNight
14%6%25%5%35%5%5%7%37%
1624
June1st to 15thNight
15%6%15%5%345%6%8%36%
1560
16th to endNight
15%6%25%5%35%5%5%8%36%
1560
July1st to 15thNight
7%424425%5%5%9%48%
1560
16th to endNight
7%3244245%6%9%48%
1641
August1st to 15thNight
8%21332445%9%52%
1578
16th to endNight
13%414423447%48%
1996
September1st to 15thNight
10%425%42445%7%47%
1950
16th to endNight
17%6%35%42445%7%39%
2109
October1st to 15thNight
21%9%35%312445%37%
2340
16th to endNight
22%12%37%5%34345%27%
2626
November1st to 15thNight
15%16%5%9%6%24445%24%
2761
16th to endNight
18%15%9%14%7%2333416%
2939
December1st to 15thNight
16%18%8%16%12%4422210%
2730
16th to endNight
14%20%8%12%9%5%6%33311%
2912

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
11%11%8%12%11%9%6%44415%
1552
16th to endDay
11%11%5%13%11%5%7%5%5%5%15%
1671
February1st to 15thDay
8%11%5%10%9%6%9%6%46%23%
1710
16th to endDay
11%12%6%8%8%46%5%46%24%
1637
March1st to 15thDay
11%8%39%6%36%447%33%
2000
16th to endDay
16%8%47%5%3445%5%34%
2379
April1st to 15thDay
15%8%36%5%34445%37%
2331
16th to endDay
19%9%35%434445%35%
2443
May1st to 15thDay
18%6%26%4245%5%7%36%
2721
16th to endDay
14%6%25%425%5%6%8%37%
2841
June1st to 15thDay
14%5%35%42445%8%41%
2730
16th to endDay
13%6%25%5%35%5%5%9%39%
2730
July1st to 15thDay
9%32431445%9%51%
2730
16th to endDay
6%31342446%9%54%
2879
August1st to 15thDay
8%5%1442345%8%51%
2633
16th to endDay
11%5%14423447%49%
2558
September1st to 15thDay
11%5%2442435%8%47%
2340
16th to endDay
20%6%35%42345%6%37%
2167
October1st to 15thDay
20%10%25%4245%5%6%32%
1950
16th to endDay
20%14%46%433445%26%
1950
November1st to 15thDay
17%15%5%10%5%24446%25%
1754
16th to endDay
17%15%7%15%9%34435%12%
1676
December1st to 15thDay
14%18%9%18%12%5%5%2238%
1560
16th to endDay
17%18%10%15%8%5%7%3336%
1664
January1st to 15thNight
13%12%6%12%10%8%8%5%3414%
2716
16th to endNight
12%13%7%13%10%6%8%5%4313%
2902
February1st to 15thNight
9%12%5%10%8%6%9%6%4422%
2473
16th to endNight
13%11%5%8%8%36%5%5%5%26%
2121
March1st to 15thNight
12%9%37%6%44346%35%
2301
16th to endNight
14%8%36%5%25%5%5%5%36%
2194
April1st to 15thNight
18%10%46%6%34345%32%
1947
16th to endNight
20%8%36%424447%33%
1791
May1st to 15thNight
20%7%37%6%34445%32%
1559
16th to endNight
14%6%25%5%35%45%6%37%
1624
June1st to 15thNight
15%6%25%5%2446%8%36%
1560
16th to endNight
14%6%35%5%25%5%48%36%
1560
July1st to 15thNight
7%414425%5%5%10%48%
1560
16th to endNight
7%4144345%6%9%48%
1641
August1st to 15thNight
8%31333445%9%52%
1578
16th to endNight
13%415%423447%48%
1996
September1st to 15thNight
10%5%26%32445%7%47%
1950
16th to endNight
17%6%35%434447%39%
2109
October1st to 15thNight
21%9%35%313345%37%
2340
16th to endNight
22%12%47%6%24445%26%
2626
November1st to 15thNight
16%16%5%9%5%2444425%
2761
16th to endNight
18%16%8%14%8%2332416%
2939
December1st to 15thNight
16%18%7%17%12%4422210%
2730
16th to endNight
15%20%8%13%9%5%6%32310%
2912

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
71%5%10%9%3
1553
16th to endDay
68%6%13%8%3
1671
February1st to 15thDay
58%6%16%15%2
1711
16th to endDay
57%5%12%16%6%
1637
March1st to 15thDay
49%5%17%18%8%
2000
16th to endDay
50%6%14%19%8%
2381
April1st to 15thDay
48%5%12%17%14%1
2331
16th to endDay
50%411%22%10%1
2443
May1st to 15thDay
45%7%12%25%7%
2721
16th to endDay
43%7%11%23%13%1
2845
June1st to 15thDay
40%6%14%26%11%
2730
16th to endDay
41%7%15%24%8%
2730
July1st to 15thDay
28%7%15%30%17%1
2581
16th to endDay
25%8%16%30%17%1
2712
August1st to 15thDay
30%6%15%34%11%1
2618
16th to endDay
33%6%15%31%11%
2558
September1st to 15thDay
34%6%16%33%8%
2340
16th to endDay
46%7%15%22%6%
2167
October1st to 15thDay
50%6%12%22%7%
1950
16th to endDay
59%5%12%16%6%
1950
November1st to 15thDay
60%5%11%16%6%
1754
16th to endDay
73%6%8%7%2
1676
December1st to 15thDay
83%46%6%
1560
16th to endDay
82%47%5%
1664
January1st to 15thNight
71%5%11%9%1
2716
16th to endNight
71%5%12%8%2
2902
February1st to 15thNight
61%6%14%13%3
2483
16th to endNight
58%5%11%17%5%
2121
March1st to 15thNight
49%6%12%20%11%
2301
16th to endNight
47%5%11%22%10%
2194
April1st to 15thNight
53%5%9%18%12%1
1947
16th to endNight
50%47%23%13%1
1791
May1st to 15thNight
53%6%10%18%8%1
1560
16th to endNight
44%8%9%22%13%1
1626
June1st to 15thNight
43%5%12%22%14%1
1560
16th to endNight
43%8%11%23%10%1
1560
July1st to 15thNight
31%7%11%30%17%1
1480
16th to endNight
29%7%15%28%15%2
1545
August1st to 15thNight
28%6%14%34%12%4
1569
16th to endNight
35%5%13%28%15%1
1996
September1st to 15thNight
35%6%12%35%10%
1950
16th to endNight
44%6%15%26%7%
2109
October1st to 15thNight
48%413%22%9%
2340
16th to endNight
58%5%11%17%7%
2626
November1st to 15thNight
61%5%10%16%5%
2761
16th to endNight
72%5%10%7%4
2939
December1st to 15thNight
81%37%6%
2730
16th to endNight
78%49%5%1
2912

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
17%430%30%14%2
135
16th to endDay
19%130%36%11%1
144
February1st to 15thDay
14%6%32%33%12%
135
16th to endDay
23%229%36%8%
120
March1st to 15thDay
11%7%22%34%21%2
135
16th to endDay
23%219%30%18%5%
237
April1st to 15thDay
20%318%36%17%2
330
16th to endDay
24%220%28%18%6%
387
May1st to 15thDay
23%213%40%15%4
543
16th to endDay
19%411%33%24%6%
597
June1st to 15thDay
15%116%36%27%3
570
16th to endDay
15%113%36%25%6%
570
July1st to 15thDay
12%110%32%36%6%
550
16th to endDay
7%10%35%34%10%
595
August1st to 15thDay
13%210%32%36%5%
549
16th to endDay
17%114%25%33%8%
470
September1st to 15thDay
15%12%30%30%10%
375
16th to endDay
28%117%30%18%2
334
October1st to 15thDay
26%421%22%20%4
180
16th to endDay
29%328%25%11%
192
November1st to 15thDay
22%332%29%12%
180
16th to endDay
29%8%29%24%7%
178
December1st to 15thDay
26%337%24%7%
135
16th to endDay
20%12%40%22%3
144
January1st to 15thNight
18%431%32%11%
975
16th to endNight
18%431%35%9%
1040
February1st to 15thNight
16%232%33%14%1
955
16th to endNight
20%225%34%15%
755
March1st to 15thNight
17%424%36%14%2
741
16th to endNight
18%320%34%17%5%
624
April1st to 15thNight
22%420%34%14%2
584
16th to endNight
25%214%34%19%3
579
May1st to 15thNight
22%220%34%16%3
585
16th to endNight
17%113%30%30%6%
611
June1st to 15thNight
18%212%36%24%5%
585
16th to endNight
16%115%31%28%6%
585
July1st to 15thNight
9%110%38%32%6%
555
16th to endNight
10%12%33%34%8%
612
August1st to 15thNight
10%19%34%37%7%
575
16th to endNight
17%114%31%29%6%
621
September1st to 15thNight
12%217%31%29%7%
585
16th to endNight
20%318%32%21%3
702
October1st to 15thNight
26%422%26%17%2
780
16th to endNight
29%6%25%26%11%
832
November1st to 15thNight
23%7%28%27%11%1
915
16th to endNight
25%9%29%27%8%
1050
December1st to 15thNight
25%9%33%24%6%
975
16th to endNight
26%6%31%27%6%1
1040
Page generated at 2018-12-01 10:35:35. Version ac04

Copyright 2018 A. Danko


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