Marquette
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Marquette clear sky chart from 2005-11-05 to 2017-08-12.

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
31%
15997
11%
46641
6%
15952
35%
15952
16%
34852

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
12%
900
6%
2506
1%
895
17%
895
8%
2125
January16th to endNight
13%
960
6%
2688
1%
960
18%
960
9%
2253
February1st to 15thNight
18%
853
5%
2349
2%
850
21%
850
10%
1946
February16th to endNight
24%
631
9%
1893
5%
631
26%
631
10%
1525
March1st to 15thNight
28%
720
12%
2160
8%
720
33%
720
16%
1600
March16th to endNight
30%
651
14%
2022
11%
651
35%
651
16%
1490
April1st to 15thNight
28%
539
10%
1797
7%
539
32%
539
14%
1317
April16th to endNight
39%
540
15%
1653
10%
540
44%
540
20%
1146
May1st to 15thNight
41%
540
12%
1500
9%
540
43%
540
19%
1094
May16th to endNight
49%
562
13%
1498
8%
561
52%
561
27%
1028
June1st to 15thNight
49%
512
10%
1412
6%
512
51%
512
25%
979
June16th to endNight
48%
512
9%
1412
5%
512
50%
512
24%
982
July1st to 15thNight
57%
510
12%
1360
7%
510
59%
510
35%
861
July16th to endNight
62%
564
15%
1417
9%
531
64%
531
38%
839
August1st to 15thNight
62%
527
21%
1425
15%
524
66%
524
38%
857
August16th to endNight
56%
525
16%
1682
13%
525
61%
525
29%
1002
September1st to 15thNight
54%
503
18%
1658
17%
503
59%
503
26%
1032
September16th to endNight
46%
657
14%
1815
10%
657
49%
657
25%
1242
October1st to 15thNight
34%
660
15%
1917
9%
660
39%
660
20%
1359
October16th to endNight
24%
704
6%
2288
5%
704
26%
704
10%
1827
November1st to 15thNight
21%
700
12%
2276
7%
700
27%
700
13%
1732
November16th to endNight
18%
867
8%
2487
4%
867
21%
867
9%
2074
December1st to 15thNight
10%
900
5%
2692
1%
900
13%
900
7%
2209
December16th to endNight
11%
960
7%
2734
1%
960
17%
960
7%
2333

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%9%47%6%35%45%7%31%
47279
Night
14%10%5%8%6%35%446%29%
46809
Cloud CoverDay
15%9%47%5%35%45%7%31%
47288
Night
14%10%5%8%6%35%446%30%
46814
TransparencyDay
52%7%12%18%7%
46965
Night
54%6%12%18%7%
46641
SeeingDay
19%6%26%30%13%2
5964
Night
20%9%29%27%11%1
15998

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
13%13%8%11%8%47%5%5%6%15%
1432
16th to endDay
10%14%5%17%10%5%45%5%414%
1536
February1st to 15thDay
10%12%5%11%11%6%8%5%5%6%15%
1511
16th to endDay
12%12%5%12%8%6%8%5%5%5%17%
1580
March1st to 15thDay
11%13%6%8%7%5%5%5%5%6%25%
1790
16th to endDay
15%11%5%9%6%35%45%6%25%
2212
April1st to 15thDay
16%10%46%5%34446%31%
2151
16th to endDay
17%11%35%435%45%6%31%
2307
May1st to 15thDay
17%9%36%5%34347%34%
2449
16th to endDay
12%7%25%5%35%5%5%7%39%
2617
June1st to 15thDay
13%6%26%5%35%45%8%37%
2520
16th to endDay
16%5%25%4345%5%8%37%
2520
July1st to 15thDay
9%325%5%2445%9%45%
2520
16th to endDay
9%41343447%9%47%
2655
August1st to 15thDay
11%3134345%5%8%48%
2440
16th to endDay
13%5%2442446%8%43%
2166
September1st to 15thDay
16%6%235%3445%7%40%
1961
16th to endDay
18%6%36%425%5%6%7%33%
1815
October1st to 15thDay
21%8%345%35%6%6%6%29%
1713
16th to endDay
23%16%48%7%345%4415%
1584
November1st to 15thDay
17%16%47%6%2335%6%26%
1582
16th to endDay
17%17%8%9%8%34445%16%
1470
December1st to 15thDay
13%14%9%14%7%45%43417%
1263
16th to endDay
16%18%8%12%8%45%44412%
1485
January1st to 15thNight
15%14%7%11%7%6%6%5%5%416%
2506
16th to endNight
11%13%7%15%10%46%5%5%5%13%
2688
February1st to 15thNight
9%14%7%11%9%5%7%6%4417%
2347
16th to endNight
13%13%6%10%9%46%45%5%19%
1893
March1st to 15thNight
13%9%5%9%6%45%435%32%
2147
16th to endNight
13%12%5%8%5%35%45%6%30%
2022
April1st to 15thNight
20%10%36%6%245%46%28%
1797
16th to endNight
18%9%45%42435%6%36%
1653
May1st to 15thNight
17%8%36%435%5%5%6%32%
1500
16th to endNight
14%5%24435%449%40%
1496
June1st to 15thNight
16%5%25%5%24446%40%
1412
16th to endNight
14%6%25%5%25%6%5%8%37%
1412
July1st to 15thNight
12%32442446%7%47%
1440
16th to endNight
8%31342345%9%53%
1513
August1st to 15thNight
7%41341435%7%54%
1434
16th to endNight
12%425%324337%49%
1682
September1st to 15thNight
13%5%244335%5%6%44%
1658
16th to endNight
17%5%245%25%447%40%
1815
October1st to 15thNight
18%5%27%5%245%5%5%36%
1917
16th to endNight
21%13%47%6%3445%5%21%
2288
November1st to 15thNight
17%15%5%6%5%3445%6%26%
2276
16th to endNight
17%14%9%8%7%34445%18%
2487
December1st to 15thNight
13%15%8%13%7%35%44418%
2692
16th to endNight
16%18%8%11%7%35%43416%
2734

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
13%13%8%11%9%45%5%46%17%
1432
16th to endDay
10%14%7%16%10%45%6%5%5%14%
1536
February1st to 15thDay
10%13%5%12%11%6%7%5%5%6%15%
1511
16th to endDay
11%13%5%12%9%5%7%5%5%5%17%
1580
March1st to 15thDay
12%12%6%9%7%5%5%45%6%25%
1800
16th to endDay
16%12%5%8%6%25%45%7%25%
2211
April1st to 15thDay
17%11%46%425%446%32%
2151
16th to endDay
17%11%35%425%45%6%31%
2307
May1st to 15thDay
17%10%26%434446%34%
2449
16th to endDay
13%6%25%4345%6%7%39%
2617
June1st to 15thDay
14%5%25%5%25%45%8%37%
2520
16th to endDay
16%5%25%4345%5%8%37%
2520
July1st to 15thDay
9%425%425%46%9%45%
2520
16th to endDay
9%3234245%6%10%47%
2655
August1st to 15thDay
12%31343446%7%48%
2440
16th to endDay
14%42342446%8%42%
2166
September1st to 15thDay
16%6%245%3445%7%40%
1961
16th to endDay
18%6%35%435%5%5%7%33%
1815
October1st to 15thDay
21%9%25%4445%5%6%30%
1713
16th to endDay
24%16%48%6%34445%16%
1584
November1st to 15thDay
18%16%48%5%2335%6%26%
1582
16th to endDay
17%17%8%9%7%34446%15%
1470
December1st to 15thDay
13%14%8%15%7%4444317%
1263
16th to endDay
16%19%9%11%7%45%345%12%
1485
January1st to 15thNight
15%14%7%11%7%5%6%5%5%417%
2506
16th to endNight
11%12%7%15%10%45%5%5%414%
2688
February1st to 15thNight
9%14%7%11%9%48%5%4418%
2340
16th to endNight
13%13%6%11%8%46%45%5%19%
1893
March1st to 15thNight
12%9%5%9%5%45%44433%
2160
16th to endNight
13%12%5%9%5%2445%5%30%
2022
April1st to 15thNight
20%11%36%6%25%446%28%
1797
16th to endNight
18%9%45%423346%35%
1653
May1st to 15thNight
17%8%37%425%5%5%6%32%
1499
16th to endNight
14%6%24435%5%48%41%
1496
June1st to 15thNight
15%5%25%5%2445%5%41%
1412
16th to endNight
14%6%25%5%35%5%5%8%37%
1412
July1st to 15thNight
12%32442445%7%47%
1440
16th to endNight
8%32242335%10%52%
1513
August1st to 15thNight
8%32332425%7%54%
1434
16th to endNight
12%424414346%49%
1682
September1st to 15thNight
14%5%2442445%6%44%
1658
16th to endNight
17%5%24424447%40%
1815
October1st to 15thNight
19%5%36%5%24445%36%
1917
16th to endNight
21%13%47%6%3445%6%21%
2288
November1st to 15thNight
17%15%5%6%5%3445%6%26%
2276
16th to endNight
17%15%9%8%7%34346%19%
2487
December1st to 15thNight
14%15%8%12%7%3444419%
2692
16th to endNight
16%18%9%11%6%35%33416%
2734

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
68%8%8%11%2
1433
16th to endDay
69%6%12%9%2
1536
February1st to 15thDay
69%8%12%8%1
1513
16th to endDay
68%6%10%10%4
1580
March1st to 15thDay
60%8%11%11%6%1
1800
16th to endDay
58%6%14%15%31
2212
April1st to 15thDay
53%6%11%19%7%1
2151
16th to endDay
52%6%8%19%10%1
2307
May1st to 15thDay
51%7%10%17%11%1
2449
16th to endDay
43%7%13%22%12%
2621
June1st to 15thDay
44%8%13%21%11%1
2520
16th to endDay
44%8%15%22%8%
2520
July1st to 15thDay
34%9%15%26%11%1
2371
16th to endDay
33%9%15%25%14%
2488
August1st to 15thDay
34%9%15%29%10%1
2425
16th to endDay
38%9%17%23%9%
2166
September1st to 15thDay
43%7%15%25%7%
1961
16th to endDay
47%9%15%21%5%
1815
October1st to 15thDay
53%8%12%20%5%
1713
16th to endDay
71%6%9%9%2
1584
November1st to 15thDay
59%5%12%15%7%
1582
16th to endDay
70%8%9%9%2
1470
December1st to 15thDay
72%5%11%8%1
1263
16th to endDay
75%6%8%7%1
1485
January1st to 15thNight
69%7%11%9%2
2506
16th to endNight
69%5%12%10%2
2688
February1st to 15thNight
65%8%11%11%3
2349
16th to endNight
65%5%10%14%3
1893
March1st to 15thNight
54%5%11%18%8%
2160
16th to endNight
54%6%11%18%7%
2022
April1st to 15thNight
56%5%9%18%7%1
1797
16th to endNight
49%5%10%21%11%1
1653
May1st to 15thNight
50%7%10%16%12%2
1500
16th to endNight
41%7%12%23%14%
1498
June1st to 15thNight
43%7%11%24%11%1
1412
16th to endNight
44%8%13%22%10%
1412
July1st to 15thNight
35%5%13%31%13%
1360
16th to endNight
28%7%17%28%15%2
1417
August1st to 15thNight
29%7%15%33%12%2
1425
16th to endNight
35%6%16%26%14%1
1682
September1st to 15thNight
37%7%13%30%10%
1658
16th to endNight
42%7%15%27%6%
1815
October1st to 15thNight
48%7%13%21%7%1
1917
16th to endNight
62%7%12%12%4
2288
November1st to 15thNight
58%6%12%14%7%
2276
16th to endNight
67%6%11%9%3
2487
December1st to 15thNight
66%6%14%10%1
2692
16th to endNight
71%6%10%10%1
2734

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%7%42%30%2
90
16th to endDay
21%9%30%32%42
96
February1st to 15thDay
20%22%38%14%4
90
16th to endDay
20%12%34%29%2
81
March1st to 15thDay
13%18%36%23%7%
90
16th to endDay
30%10%26%22%10%
260
April1st to 15thDay
26%7%25%31%9%
270
16th to endDay
27%5%30%22%11%2
270
May1st to 15thDay
21%7%33%25%10%1
406
16th to endDay
19%5%28%30%11%4
517
June1st to 15thDay
16%5%27%36%11%2
495
16th to endDay
18%428%30%13%3
495
July1st to 15thDay
13%221%37%21%3
475
16th to endDay
8%322%42%19%3
515
August1st to 15thDay
14%220%38%18%5%
449
16th to endDay
20%415%32%20%5%
268
September1st to 15thDay
19%319%28%22%7%
255
16th to endDay
19%430%27%15%1
254
October1st to 15thDay
25%7%31%23%10%1
164
16th to endDay
37%9%31%19%2
96
November1st to 15thDay
21%10%28%30%10%
90
16th to endDay
30%17%23%24%31
90
December1st to 15thDay
32%9%36%16%4
61
16th to endDay
27%20%41%10%
87
January1st to 15thNight
22%14%39%19%4
900
16th to endNight
17%15%39%20%5%1
960
February1st to 15thNight
17%14%36%24%6%
853
16th to endNight
21%9%32%28%7%
631
March1st to 15thNight
18%12%34%24%9%
720
16th to endNight
20%11%29%26%11%1
651
April1st to 15thNight
27%8%28%28%6%
539
16th to endNight
24%5%25%29%12%2
540
May1st to 15thNight
21%5%25%31%13%2
540
16th to endNight
17%324%35%15%2
563
June1st to 15thNight
18%319%38%18%1
512
16th to endNight
17%323%35%17%2
512
July1st to 15thNight
14%220%36%23%3
510
16th to endNight
9%220%41%22%3
564
August1st to 15thNight
10%219%37%28%2
527
16th to endNight
15%220%37%21%3
525
September1st to 15thNight
16%420%33%21%3
503
16th to endNight
19%6%21%36%14%1
657
October1st to 15thNight
24%8%27%27%11%1
660
16th to endNight
29%11%29%21%6%
704
November1st to 15thNight
28%11%34%22%4
700
16th to endNight
26%15%33%19%4
867
December1st to 15thNight
21%19%38%16%3
900
16th to endNight
26%13%35%19%41
960
Page generated at 2017-08-13 14:16:26. Version ac04

Copyright 2017 A. Danko


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