Oshkosh
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oshkosh clear sky chart from 2005-11-06 to 2024-02-15.

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
35%
24898
16%
80466
9%
24806
42%
24806
20%
55360

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 10thNight
22%
939
12%
4364
5%
926
30%
926
11%
3073
January11th to 20thNight
22%
948
10%
4382
4%
930
28%
930
8%
3370
January21st to endNight
20%
1036
7%
4840
3%
1023
27%
1023
9%
3714
February1st to 10thNight
22%
950
14%
2470
3%
950
30%
950
19%
1824
February11th to 20thNight
25%
762
19%
2197
6%
762
36%
762
19%
1517
February21st to endNight
24%
592
16%
1776
4%
592
35%
592
18%
1236
March1st to 10thNight
33%
720
16%
2160
9%
720
38%
720
21%
1464
March11th to 20thNight
34%
680
20%
2116
11%
680
43%
680
24%
1368
March21st to endNight
35%
594
20%
1980
16%
594
43%
594
19%
1353
April1st to 10thNight
25%
540
14%
1800
8%
540
34%
540
16%
1261
April11th to 20thNight
34%
533
18%
1775
14%
533
41%
533
19%
1191
April21st to endNight
35%
540
16%
1677
9%
540
43%
540
21%
1152
May1st to 10thNight
32%
540
14%
1558
9%
540
37%
540
21%
1105
May11th to 20thNight
37%
531
19%
1417
10%
531
44%
531
25%
990
May21st to endNight
47%
583
14%
1552
9%
582
51%
582
30%
1031
June1st to 10thNight
49%
540
16%
1440
8%
540
54%
540
34%
907
June11th to 20thNight
44%
540
16%
1440
8%
540
49%
540
31%
935
June21st to endNight
57%
540
16%
1440
9%
540
60%
540
36%
880
July1st to 10thNight
65%
525
18%
1400
11%
525
68%
525
44%
803
July11th to 20thNight
58%
522
19%
1392
11%
522
62%
522
40%
833
July21st to endNight
65%
591
22%
1487
15%
558
68%
558
41%
883
August1st to 10thNight
66%
537
22%
1423
17%
534
69%
534
39%
863
August11th to 20thNight
63%
534
21%
1682
18%
534
68%
534
35%
968
August21st to endNight
60%
594
22%
1980
22%
594
65%
594
34%
1110
September1st to 10thNight
54%
540
22%
1800
21%
540
60%
540
31%
1052
September11th to 20thNight
51%
610
28%
1870
22%
610
59%
610
33%
1089
September21st to endNight
45%
720
21%
1980
13%
720
50%
720
28%
1269
October1st to 10thNight
44%
720
21%
2074
15%
720
49%
720
28%
1325
October11th to 20thNight
28%
720
17%
2183
7%
720
39%
720
20%
1514
October21st to endNight
29%
792
14%
2574
9%
792
36%
792
17%
1793
November1st to 10thNight
31%
740
23%
2406
14%
740
43%
740
24%
1503
November11th to 20thNight
18%
760
14%
2470
7%
760
27%
760
13%
1792
November21st to endNight
23%
950
16%
2660
6%
950
32%
950
19%
1882
December1st to 10thNight
19%
950
9%
2660
3%
950
24%
950
13%
2042
December11th to 20thNight
18%
950
12%
3213
3%
948
26%
948
12%
2427
December21st to endNight
16%
1035
7%
4828
3%
1026
23%
1026
7%
3841

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
12%8%37%6%35%5%5%7%38%
78198
Night
13%10%47%6%3445%6%37%
80936
TransparencyDay
45%7%13%23%11%1
77899
Night
48%6%12%22%12%1
80756
SeeingDay
16%9%28%27%15%5%
14864
Night
17%9%31%30%12%1
24934

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
11%12%7%12%7%45%5%46%27%
2527
11th to 20thDay
11%10%5%11%8%48%9%7%7%20%
2530
21st to endDay
16%14%7%12%9%45%445%21%
2783
February1st to 10thDay
9%11%410%7%35%6%5%6%32%
1710
11th to 20thDay
11%9%5%7%6%345%5%7%37%
1743
21st to endDay
13%9%5%9%8%5%5%5%5%6%33%
1480
March1st to 10thDay
14%9%37%6%345%47%38%
1800
11th to 20thDay
11%8%35%5%35%5%5%7%40%
1861
21st to endDay
17%9%37%6%46%5%48%33%
2376
April1st to 10thDay
15%10%5%6%5%46%5%5%7%32%
2160
11th to 20thDay
19%8%35%5%35%45%7%35%
2134
21st to endDay
18%7%37%6%45%45%7%34%
2282
May1st to 10thDay
14%7%36%6%45%6%7%7%35%
2399
11th to 20thDay
16%5%25%5%35%5%5%8%41%
2479
21st to endDay
11%5%25%6%46%6%6%8%41%
2725
June1st to 10thDay
10%5%35%5%3447%9%47%
2520
11th to 20thDay
12%5%35%5%35%46%9%45%
2520
21st to endDay
8%5%25%5%346%6%11%45%
2520
July1st to 10thDay
5%324436%5%7%11%51%
2520
11th to 20thDay
7%424425%6%6%11%49%
2520
21st to endDay
7%424435%5%5%9%51%
2743
August1st to 10thDay
7%4245%35%6%7%11%47%
2507
11th to 20thDay
10%5%24436%46%10%44%
2214
21st to endDay
11%5%25%435%5%6%7%47%
2376
September1st to 10thDay
12%5%35%5%3446%7%46%
2160
11th to 20thDay
12%5%245%3445%8%50%
2070
21st to endDay
12%7%36%5%35%5%6%8%41%
1980
October1st to 10thDay
15%6%35%4345%5%6%44%
1882
11th to 20thDay
19%9%37%6%45%5%6%7%30%
1775
21st to endDay
16%9%48%6%3335%5%37%
1782
November1st to 10thDay
12%7%36%6%25%45%7%42%
1672
11th to 20thDay
12%12%5%9%9%345%6%6%29%
1707
21st to endDay
15%11%47%5%4445%7%33%
1520
December1st to 10thDay
12%12%5%11%8%5%6%5%6%6%24%
1520
11th to 20thDay
12%12%5%9%8%46%6%6%6%25%
1918
21st to endDay
18%17%7%13%9%4433417%
2783
January1st to 10thNight
13%14%9%9%6%3333434%
4428
11th to 20thNight
11%13%6%13%8%47%8%5%5%20%
4440
21st to endNight
14%18%8%11%6%3443425%
4884
February1st to 10thNight
10%12%6%9%7%3445%5%33%
2470
11th to 20thNight
10%8%5%8%7%45%445%39%
2196
21st to endNight
17%11%5%7%5%34345%36%
1776
March1st to 10thNight
15%9%36%5%35%5%6%6%38%
2160
11th to 20thNight
12%7%45%5%46%45%7%42%
2116
21st to endNight
17%8%47%6%3445%7%35%
1980
April1st to 10thNight
19%9%37%5%3445%6%35%
1800
11th to 20thNight
21%7%36%5%3346%7%36%
1775
21st to endNight
16%8%36%5%345%47%37%
1677
May1st to 10thNight
17%9%37%6%4445%8%34%
1558
11th to 20thNight
18%7%25%6%35%5%47%38%
1416
21st to endNight
12%5%36%6%35%5%6%9%41%
1551
June1st to 10thNight
9%5%25%5%35%5%5%9%48%
1440
11th to 20thNight
11%6%35%5%35%5%5%8%44%
1440
21st to endNight
7%3244345%7%10%49%
1440
July1st to 10thNight
7%42342337%9%55%
1440
11th to 20thNight
7%425%5%335%6%9%51%
1440
21st to endNight
6%325%5%346%6%8%53%
1575
August1st to 10thNight
8%5%15%3246%7%10%49%
1432
11th to 20thNight
8%5%25%4345%5%8%52%
1682
21st to endNight
10%42443346%8%52%
1980
September1st to 10thNight
10%5%2442445%8%50%
1800
11th to 20thNight
13%424424446%53%
1870
21st to endNight
13%6%35%6%34447%46%
1980
October1st to 10thNight
14%6%35%5%3445%6%47%
2074
11th to 20thNight
17%8%36%5%35%45%7%36%
2183
21st to endNight
18%10%37%5%35%45%7%33%
2574
November1st to 10thNight
12%7%35%5%3445%8%44%
2406
11th to 20thNight
14%11%5%8%7%45%5%45%31%
2470
21st to endNight
15%10%47%6%34447%36%
2660
December1st to 10thNight
13%13%5%8%7%46%5%6%7%26%
2660
11th to 20thNight
13%15%5%9%7%45%446%28%
3279
21st to endNight
20%18%5%9%7%3444422%
4884

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 10thDay
58%6%15%15%5%
2528
11th to 20thDay
61%6%12%16%5%
2530
21st to endDay
65%6%10%14%4
2783
February1st to 10thDay
52%6%12%20%10%1
1710
11th to 20thDay
46%6%11%23%11%2
1753
21st to endDay
53%6%11%19%10%2
1480
March1st to 10thDay
47%7%14%22%9%2
1800
11th to 20thDay
43%7%15%20%13%2
1861
21st to endDay
51%7%13%21%7%1
2376
April1st to 10thDay
50%7%13%19%10%
2160
11th to 20thDay
49%6%10%20%13%2
2134
21st to endDay
50%7%11%20%11%1
2282
May1st to 10thDay
46%7%14%23%10%1
2399
11th to 20thDay
41%7%14%24%12%2
2483
21st to endDay
39%9%12%24%13%2
2725
June1st to 10thDay
34%7%13%29%15%2
2520
11th to 20thDay
36%8%13%27%14%1
2520
21st to endDay
32%11%14%27%14%1
2520
July1st to 10thDay
26%9%15%33%15%2
2451
11th to 20thDay
29%9%16%28%16%3
2445
21st to endDay
29%9%16%27%16%4
2591
August1st to 10thDay
29%9%18%31%11%2
2492
11th to 20thDay
34%9%14%28%13%1
2214
21st to endDay
35%9%13%25%17%1
2376
September1st to 10thDay
38%7%13%25%16%1
2160
11th to 20thDay
34%7%15%33%11%1
2070
21st to endDay
42%7%12%30%9%
1980
October1st to 10thDay
41%7%12%27%13%
1882
11th to 20thDay
52%6%14%19%8%1
1775
21st to endDay
51%6%13%19%11%
1782
November1st to 10thDay
42%6%13%24%14%1
1672
11th to 20thDay
55%6%14%16%7%1
1707
21st to endDay
52%5%15%20%6%1
1520
December1st to 10thDay
60%7%12%16%5%
1520
11th to 20thDay
58%6%16%14%5%1
1915
21st to endDay
72%5%8%10%4
2783
January1st to 10thNight
57%410%19%9%1
4428
11th to 20thNight
65%411%13%7%
4440
21st to endNight
64%5%10%16%6%
4884
February1st to 10thNight
53%5%10%21%11%2
2470
11th to 20thNight
49%410%23%12%2
2197
21st to endNight
51%414%19%10%2
1776
March1st to 10thNight
45%7%14%21%11%2
2160
11th to 20thNight
42%5%13%23%15%2
2116
21st to endNight
49%5%9%23%12%2
1980
April1st to 10thNight
51%6%8%16%17%2
1800
11th to 20thNight
47%5%9%19%15%4
1775
21st to endNight
47%6%11%20%15%1
1677
May1st to 10thNight
48%7%12%20%12%1
1558
11th to 20thNight
46%5%11%23%13%2
1417
21st to endNight
39%7%14%24%15%2
1552
June1st to 10thNight
33%8%12%29%17%1
1440
11th to 20thNight
36%8%10%27%17%2
1440
21st to endNight
29%9%17%27%14%3
1440
July1st to 10thNight
26%5%14%31%20%4
1400
11th to 20thNight
28%7%15%29%18%3
1392
21st to endNight
25%10%14%30%17%4
1487
August1st to 10thNight
29%8%16%29%16%3
1423
11th to 20thNight
30%7%15%31%16%1
1682
21st to endNight
30%6%12%28%20%3
1980
September1st to 10thNight
33%7%11%24%24%2
1800
11th to 20thNight
32%6%12%34%16%1
1870
21st to endNight
38%6%12%29%14%1
1980
October1st to 10thNight
39%6%9%29%16%2
2074
11th to 20thNight
46%7%13%20%12%1
2183
21st to endNight
50%6%13%20%11%
2574
November1st to 10thNight
39%6%12%25%16%2
2406
11th to 20thNight
55%5%13%16%10%1
2470
21st to endNight
50%5%16%23%6%1
2660
December1st to 10thNight
57%7%12%18%6%1
2660
11th to 20thNight
59%5%12%17%7%1
3281
21st to endNight
66%6%9%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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
17%11%29%30%10%2
270
11th to 20thDay
18%13%33%29%6%1
270
21st to endDay
18%8%36%30%7%1
297
February1st to 10thDay
10%14%42%25%8%1
270
11th to 20thDay
16%15%38%24%8%
252
21st to endDay
17%17%41%21%31
198
March1st to 10thDay
22%11%39%19%7%2
240
11th to 20thDay
20%14%28%26%7%5%
244
21st to endDay
25%11%29%24%9%2
462
April1st to 10thDay
25%10%33%25%7%
420
11th to 20thDay
25%14%27%21%10%4
412
21st to endDay
21%12%26%24%14%3
420
May1st to 10thDay
18%10%34%27%10%2
482
11th to 20thDay
18%10%29%27%12%4
625
21st to endDay
15%7%28%26%18%6%
679
June1st to 10thDay
10%7%29%32%18%5%
630
11th to 20thDay
16%6%28%29%17%5%
630
21st to endDay
10%7%25%34%18%5%
630
July1st to 10thDay
8%317%31%28%12%
621
11th to 20thDay
8%6%24%33%20%10%
618
21st to endDay
9%324%33%23%9%
684
August1st to 10thDay
7%321%31%28%9%
626
11th to 20thDay
14%315%24%31%13%
473
21st to endDay
13%7%21%28%20%11%
495
September1st to 10thDay
14%7%22%27%23%7%
450
11th to 20thDay
12%6%18%35%18%10%
450
21st to endDay
16%12%25%22%19%7%
450
October1st to 10thDay
20%10%22%27%17%5%
352
11th to 20thDay
20%19%29%24%8%
270
21st to endDay
23%13%40%16%7%1
297
November1st to 10thDay
13%16%34%26%9%1
270
11th to 20thDay
16%18%40%18%8%
270
21st to endDay
22%16%38%19%5%
270
December1st to 10thDay
17%17%41%20%5%
270
11th to 20thDay
21%13%39%20%7%1
270
21st to endDay
25%14%37%19%4
297
January1st to 10thNight
17%13%35%27%8%
950
11th to 20thNight
20%9%37%26%6%1
950
21st to endNight
19%9%35%29%7%
1045
February1st to 10thNight
16%12%38%27%7%1
950
11th to 20thNight
15%12%39%26%8%
765
21st to endNight
22%11%34%28%5%1
592
March1st to 10thNight
20%9%31%29%9%2
720
11th to 20thNight
17%9%35%31%6%1
680
21st to endNight
21%6%29%32%10%2
594
April1st to 10thNight
24%10%34%25%6%
540
11th to 20thNight
23%9%30%30%7%1
533
21st to endNight
21%8%32%31%8%
540
May1st to 10thNight
21%9%33%29%9%
540
11th to 20thNight
20%5%33%32%10%
531
21st to endNight
14%5%25%37%18%1
584
June1st to 10thNight
10%5%28%39%17%1
540
11th to 20thNight
14%430%38%12%1
540
21st to endNight
9%425%44%18%1
540
July1st to 10thNight
9%217%43%27%2
525
11th to 20thNight
9%422%40%22%2
522
21st to endNight
6%219%46%25%2
591
August1st to 10thNight
9%215%47%25%2
537
11th to 20thNight
9%218%38%29%4
534
21st to endNight
11%419%39%25%2
594
September1st to 10thNight
11%5%24%36%19%4
540
11th to 20thNight
14%425%32%22%4
610
21st to endNight
14%9%26%28%21%2
720
October1st to 10thNight
15%9%26%32%17%1
720
11th to 20thNight
23%11%32%26%7%
720
21st to endNight
24%12%30%26%8%1
792
November1st to 10thNight
16%11%37%27%8%1
740
11th to 20thNight
20%18%37%21%5%
760
21st to endNight
20%14%36%23%6%
950
December1st to 10thNight
20%15%38%20%6%
950
11th to 20thNight
23%12%35%23%6%1
950
21st to endNight
27%11%34%24%4
1045
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