Oshkosh
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oshkosh clear sky chart from 2005-11-05 to 2017-12-02.

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
36%
16387
16%
47796
9%
16345
42%
16345
22%
32559

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
23%
900
13%
2506
5%
895
30%
895
17%
1862
January16th to endNight
19%
960
12%
2688
2%
960
27%
960
15%
2052
February1st to 15thNight
23%
847
14%
2259
3%
847
31%
847
19%
1612
February16th to endNight
29%
631
16%
1893
6%
631
37%
631
17%
1341
March1st to 15thNight
33%
720
15%
2160
8%
720
38%
720
21%
1466
March16th to endNight
37%
609
18%
2010
16%
609
43%
609
20%
1361
April1st to 15thNight
28%
539
15%
1797
11%
539
37%
539
19%
1244
April16th to endNight
37%
540
17%
1717
12%
540
44%
540
21%
1170
May1st to 15thNight
31%
540
16%
1518
8%
540
38%
540
22%
1066
May16th to endNight
46%
562
15%
1498
8%
561
51%
561
32%
987
June1st to 15thNight
49%
540
14%
1440
7%
540
53%
540
30%
941
June16th to endNight
53%
540
14%
1440
8%
540
56%
540
34%
907
July1st to 15thNight
64%
510
17%
1360
10%
510
66%
510
43%
782
July16th to endNight
62%
564
19%
1417
12%
531
65%
531
41%
838
August1st to 15thNight
70%
539
23%
1488
19%
536
72%
536
41%
860
August16th to endNight
60%
573
21%
1910
21%
573
64%
573
31%
1122
September1st to 15thNight
57%
540
25%
1800
23%
540
64%
540
32%
1026
September16th to endNight
51%
705
23%
1968
16%
705
57%
705
33%
1203
October1st to 15thNight
40%
720
20%
2103
13%
720
46%
720
26%
1369
October16th to endNight
31%
768
16%
2453
9%
768
39%
768
19%
1679
November1st to 15thNight
30%
760
20%
2471
13%
760
38%
760
21%
1623
November16th to endNight
24%
910
14%
2665
6%
910
31%
910
16%
1941
December1st to 15thNight
17%
910
8%
2547
2%
910
23%
910
13%
1982
December16th to endNight
17%
960
11%
2688
2%
960
25%
960
12%
2125

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%7%36%5%35%45%7%38%
48664
Night
13%8%36%5%34446%38%
47964
Cloud CoverDay
12%7%36%5%35%45%7%38%
48673
Night
13%8%36%5%3445%6%38%
47969
TransparencyDay
44%7%13%23%10%1
48350
Night
45%6%12%22%12%1
47796
SeeingDay
16%7%27%27%16%5%
6314
Night
18%7%30%30%12%1
16391

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
12%11%49%6%35%5%6%6%29%
1432
16th to endDay
11%12%6%13%7%34446%24%
1536
February1st to 15thDay
11%12%46%6%245%5%5%33%
1601
16th to endDay
12%8%47%7%35%5%4435%
1580
March1st to 15thDay
14%8%36%5%34447%36%
1790
16th to endDay
16%8%35%435%448%36%
2226
April1st to 15thDay
16%9%45%5%35%45%6%32%
2151
16th to endDay
19%7%36%5%34346%35%
2241
May1st to 15thDay
16%6%36%6%35%5%5%6%34%
2431
16th to endDay
10%315%5%35%5%6%8%42%
2617
June1st to 15thDay
12%435%42446%8%41%
2520
16th to endDay
7%425%5%345%7%10%42%
2520
July1st to 15thDay
5%3143345%7%10%48%
2520
16th to endDay
7%424425%5%5%9%46%
2655
August1st to 15thDay
7%314435%5%7%9%45%
2462
16th to endDay
12%4245%2446%8%45%
2292
September1st to 15thDay
11%42442345%7%49%
2160
16th to endDay
9%5%26%5%35%35%8%42%
1980
October1st to 15thDay
18%7%3432435%6%40%
1854
16th to endDay
15%8%37%6%3435%7%34%
1770
November1st to 15thDay
14%9%37%5%2445%6%36%
1717
16th to endDay
14%11%47%7%3435%7%31%
1623
December1st to 15thDay
16%10%5%8%6%47%6%5%5%22%
1450
16th to endDay
18%14%6%8%8%46%345%20%
1536
January1st to 15thNight
14%11%6%7%5%25%44432%
2506
16th to endNight
11%12%5%11%6%45%44428%
2688
February1st to 15thNight
12%11%5%7%5%2334438%
2257
16th to endNight
13%10%49%5%34435%34%
1893
March1st to 15thNight
15%8%36%434446%39%
2147
16th to endNight
15%7%36%5%25%45%6%35%
2010
April1st to 15thNight
21%8%26%423346%34%
1797
16th to endNight
18%7%35%5%2345%5%38%
1717
May1st to 15thNight
19%5%26%5%34447%36%
1518
16th to endNight
10%425%5%35%5%5%9%41%
1496
June1st to 15thNight
10%5%15%4246%49%44%
1440
16th to endNight
7%425%4245%6%10%45%
1440
July1st to 15thNight
6%2135%2337%8%55%
1440
16th to endNight
5%215%32446%10%51%
1513
August1st to 15thNight
6%3143236%6%9%51%
1497
16th to endNight
9%5%2442345%7%49%
1910
September1st to 15thNight
10%423423447%53%
1800
16th to endNight
11%5%24424347%49%
1968
October1st to 15thNight
16%5%15%424346%44%
2103
16th to endNight
16%8%35%5%3445%7%35%
2453
November1st to 15thNight
14%8%46%5%23336%41%
2471
16th to endNight
16%9%37%6%34446%32%
2665
December1st to 15thNight
16%13%5%7%5%46%45%6%24%
2547
16th to endNight
18%15%5%7%6%34445%25%
2688

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
12%11%49%6%36%5%5%7%28%
1432
16th to endDay
12%12%6%12%8%34446%24%
1536
February1st to 15thDay
11%12%47%6%245%5%5%32%
1601
16th to endDay
12%9%47%6%345%45%35%
1580
March1st to 15thDay
14%8%46%5%345%47%36%
1800
16th to endDay
16%8%26%425%448%36%
2225
April1st to 15thDay
16%8%46%5%35%45%6%33%
2151
16th to endDay
19%7%36%5%34346%35%
2241
May1st to 15thDay
16%6%26%6%45%5%5%7%34%
2431
16th to endDay
10%3245%35%5%6%8%42%
2617
June1st to 15thDay
12%5%35%42447%8%41%
2520
16th to endDay
7%425%5%35%6%6%10%43%
2520
July1st to 15thDay
5%324335%5%7%11%48%
2520
16th to endDay
8%424426%5%6%9%46%
2655
August1st to 15thDay
7%314435%5%7%10%45%
2462
16th to endDay
12%41443445%7%45%
2292
September1st to 15thDay
11%42443345%7%49%
2160
16th to endDay
9%5%35%6%3445%8%43%
1980
October1st to 15thDay
18%6%25%423445%41%
1854
16th to endDay
15%8%37%6%3435%6%34%
1770
November1st to 15thDay
14%9%37%6%2445%6%35%
1717
16th to endDay
14%11%47%6%3445%7%30%
1623
December1st to 15thDay
15%11%49%6%47%6%5%5%21%
1450
16th to endDay
18%14%6%8%9%45%44420%
1536
January1st to 15thNight
14%12%6%7%5%35%44432%
2506
16th to endNight
11%12%6%11%6%45%445%28%
2688
February1st to 15thNight
12%11%5%7%6%2434438%
2250
16th to endNight
13%10%48%5%34345%34%
1893
March1st to 15thNight
15%7%35%434446%39%
2160
16th to endNight
15%7%36%5%35%45%6%35%
2010
April1st to 15thNight
21%8%36%42335%6%34%
1797
16th to endNight
18%7%35%42345%6%38%
1717
May1st to 15thNight
19%6%26%5%44446%35%
1517
16th to endNight
11%325%5%25%5%6%10%41%
1496
June1st to 15thNight
9%5%245%25%5%5%7%45%
1440
16th to endNight
7%325%4345%6%10%45%
1440
July1st to 15thNight
6%31342337%8%55%
1440
16th to endNight
5%3244245%6%10%51%
1513
August1st to 15thNight
6%315%3236%6%9%51%
1497
16th to endNight
9%5%25%42335%6%49%
1910
September1st to 15thNight
10%424414346%53%
1800
16th to endNight
11%5%24434337%49%
1968
October1st to 15thNight
15%5%25%424346%44%
2103
16th to endNight
16%8%36%5%2435%7%35%
2453
November1st to 15thNight
15%8%36%423346%41%
2471
16th to endNight
16%10%37%7%34446%31%
2665
December1st to 15thNight
16%13%5%7%6%46%45%6%24%
2547
16th to endNight
18%15%5%7%6%34335%25%
2688

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
55%5%12%19%6%
1433
16th to endDay
60%6%11%14%6%
1536
February1st to 15thDay
51%6%11%21%7%
1603
16th to endDay
50%6%10%21%9%1
1580
March1st to 15thDay
46%7%14%20%9%1
1800
16th to endDay
47%7%15%22%5%
2226
April1st to 15thDay
51%6%11%20%10%
2151
16th to endDay
49%6%10%19%10%2
2241
May1st to 15thDay
48%6%12%23%8%
2431
16th to endDay
36%9%13%25%13%1
2621
June1st to 15thDay
38%9%12%28%11%
2520
16th to endDay
33%10%15%24%14%
2520
July1st to 15thDay
28%10%13%31%14%2
2371
16th to endDay
32%8%15%24%15%3
2488
August1st to 15thDay
30%9%16%30%11%1
2447
16th to endDay
36%8%12%26%14%1
2292
September1st to 15thDay
34%6%13%30%15%
2160
16th to endDay
37%7%14%30%9%
1980
October1st to 15thDay
44%5%13%24%12%
1854
16th to endDay
50%6%13%22%7%
1770
November1st to 15thDay
47%6%12%21%10%1
1717
16th to endDay
52%6%17%18%5%
1623
December1st to 15thDay
62%6%12%14%4
1450
16th to endDay
67%6%8%11%5%
1536
January1st to 15thNight
55%410%17%10%
2506
16th to endNight
57%5%12%17%7%
2688
February1st to 15thNight
50%410%23%9%1
2259
16th to endNight
52%412%21%8%
1893
March1st to 15thNight
45%6%13%20%12%1
2160
16th to endNight
47%5%11%24%9%
2010
April1st to 15thNight
50%5%7%20%14%1
1797
16th to endNight
46%6%10%19%14%2
1717
May1st to 15thNight
47%6%11%22%12%
1518
16th to endNight
37%6%15%23%15%1
1498
June1st to 15thNight
35%9%10%29%14%
1440
16th to endNight
31%8%14%25%16%2
1440
July1st to 15thNight
26%5%13%30%20%3
1360
16th to endNight
26%8%14%31%16%3
1417
August1st to 15thNight
27%6%14%34%15%1
1488
16th to endNight
33%6%11%28%17%2
1910
September1st to 15thNight
32%5%9%26%25%1
1800
16th to endNight
34%5%11%33%13%1
1968
October1st to 15thNight
40%6%10%26%15%1
2103
16th to endNight
47%6%14%20%11%
2453
November1st to 15thNight
44%5%11%22%13%2
2471
16th to endNight
53%5%16%18%6%
2665
December1st to 15thNight
59%6%12%15%5%
2547
16th to endNight
62%5%11%14%5%
2688

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
25%6%35%27%4
90
16th to endDay
18%7%34%29%10%
96
February1st to 15thDay
16%15%40%20%7%
90
16th to endDay
19%12%37%20%8%1
81
March1st to 15thDay
27%12%32%20%43
90
16th to endDay
32%423%25%10%2
231
April1st to 15thDay
25%8%28%27%10%
270
16th to endDay
23%10%28%24%10%4
270
May1st to 15thDay
20%10%32%25%9%3
388
16th to endDay
14%8%31%25%13%5%
517
June1st to 15thDay
14%5%29%28%18%3
495
16th to endDay
9%9%30%31%14%4
495
July1st to 15thDay
9%422%31%22%10%
475
16th to endDay
9%228%30%20%8%
515
August1st to 15thDay
9%218%32%27%8%
457
16th to endDay
17%416%26%22%12%
332
September1st to 15thDay
13%419%28%21%13%
315
16th to endDay
11%7%19%29%26%5%
314
October1st to 15thDay
20%9%24%26%15%3
189
16th to endDay
19%9%38%23%9%
144
November1st to 15thDay
17%9%30%28%13%1
135
16th to endDay
25%15%39%12%6%
135
December1st to 15thDay
22%12%48%14%1
94
16th to endDay
34%21%35%7%1
96
January1st to 15thNight
20%11%35%24%7%
900
16th to endNight
18%8%41%26%5%
960
February1st to 15thNight
17%11%36%27%5%
850
16th to endNight
18%10%32%29%8%
631
March1st to 15thNight
20%7%33%28%10%1
720
16th to endNight
19%431%32%10%1
609
April1st to 15thNight
25%6%34%26%6%
539
16th to endNight
21%6%31%30%9%
540
May1st to 15thNight
21%7%35%26%8%
540
16th to endNight
12%431%36%15%
563
June1st to 15thNight
12%426%39%16%
540
16th to endNight
10%327%42%16%1
540
July1st to 15thNight
8%119%44%24%1
510
16th to endNight
6%122%43%25%1
564
August1st to 15thNight
8%113%48%25%1
539
16th to endNight
12%317%38%25%3
573
September1st to 15thNight
12%321%34%21%6%
540
16th to endNight
13%6%23%29%23%3
705
October1st to 15thNight
20%7%27%28%15%1
720
16th to endNight
22%9%32%25%9%
768
November1st to 15thNight
19%10%35%24%8%
760
16th to endNight
21%13%34%22%6%
910
December1st to 15thNight
25%13%37%19%4
910
16th to endNight
26%9%36%22%3
960
Page generated at 2017-12-03 10:16:39. Version ac04

Copyright 2017 A. Danko


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