Burr Oak State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Burr Oak State Park clear sky chart from 2005-11-05 to 2017-10-06.

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
38%
15652
17%
47122
12%
15611
44%
15611
22%
31990

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
14%
720
11%
2327
5%
716
21%
716
9%
1874
January16th to endNight
18%
768
13%
2496
7%
768
26%
768
12%
1848
February1st to 15thNight
21%
701
12%
2269
6%
701
28%
701
14%
1670
February16th to endNight
16%
631
12%
1893
5%
631
23%
631
12%
1457
March1st to 15thNight
25%
720
17%
2017
9%
720
32%
720
18%
1448
March16th to endNight
26%
768
16%
2112
8%
768
34%
768
20%
1501
April1st to 15thNight
26%
688
15%
1889
6%
688
33%
688
22%
1299
April16th to endNight
34%
540
22%
1620
10%
540
43%
540
25%
1043
May1st to 15thNight
37%
540
13%
1620
8%
540
42%
540
19%
1134
May16th to endNight
53%
562
17%
1684
12%
561
58%
561
29%
1068
June1st to 15thNight
58%
540
16%
1620
13%
540
63%
540
33%
967
June16th to endNight
56%
540
16%
1620
13%
540
61%
540
31%
994
July1st to 15thNight
56%
510
14%
1530
11%
510
59%
510
28%
989
July16th to endNight
67%
564
17%
1595
15%
531
70%
531
33%
959
August1st to 15thNight
67%
539
22%
1609
17%
536
70%
536
33%
959
August16th to endNight
66%
588
25%
1734
22%
588
68%
588
37%
998
September1st to 15thNight
62%
720
26%
1965
20%
720
65%
720
37%
1186
September16th to endNight
56%
717
27%
1980
21%
717
61%
717
31%
1247
October1st to 15thNight
51%
684
24%
1989
21%
684
56%
684
31%
1219
October16th to endNight
34%
704
22%
2112
15%
704
43%
704
22%
1408
November1st to 15thNight
40%
700
24%
2265
18%
700
49%
700
27%
1343
November16th to endNight
31%
720
16%
2340
11%
720
38%
720
16%
1618
December1st to 15thNight
22%
720
10%
2340
7%
720
26%
720
11%
1815
December16th to endNight
18%
768
10%
2496
4%
768
25%
768
10%
1946

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
16%8%36%5%3445%7%33%
48062
Night
15%8%35%5%2445%6%37%
47315
Cloud CoverDay
16%8%36%5%35%45%7%33%
48072
Night
15%8%35%5%3445%6%37%
47319
TransparencyDay
49%5%11%20%12%1
47773
Night
46%5%11%20%13%2
47122
SeeingDay
20%10%24%21%15%7%
5494
Night
20%10%24%27%15%2
15656

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
21%14%6%8%6%2344421%
1611
16th to endDay
18%15%7%9%6%34345%21%
1728
February1st to 15thDay
20%12%5%9%5%2344426%
1591
16th to endDay
16%16%6%9%423335%29%
1580
March1st to 15thDay
21%12%45%5%24336%30%
1930
16th to endDay
20%8%46%5%34346%32%
2112
April1st to 15thDay
19%10%25%5%33346%35%
2069
16th to endDay
16%7%36%5%2445%6%37%
2340
May1st to 15thDay
20%8%46%6%3446%7%28%
2331
16th to endDay
12%5%25%6%35%6%6%8%37%
2431
June1st to 15thDay
11%4245%45%6%6%9%37%
2340
16th to endDay
13%5%26%6%46%6%7%10%31%
2340
July1st to 15thDay
15%6%26%6%36%6%6%9%31%
2340
16th to endDay
11%435%6%37%6%7%9%34%
2465
August1st to 15thDay
9%5%26%5%46%7%8%10%32%
2340
16th to endDay
9%425%5%45%5%5%9%41%
2456
September1st to 15thDay
14%42433435%6%44%
1992
16th to endDay
15%6%25%5%23445%42%
1980
October1st to 15thDay
14%6%26%42445%8%40%
1768
16th to endDay
22%6%25%323235%41%
1760
November1st to 15thDay
12%7%35%323346%46%
1590
16th to endDay
19%11%46%5%23445%32%
1620
December1st to 15thDay
24%15%6%7%5%2434421%
1620
16th to endDay
22%17%5%8%423345%21%
1728
January1st to 15thNight
22%14%7%9%6%3443321%
2327
16th to endNight
18%13%5%8%6%33445%27%
2496
February1st to 15thNight
20%10%46%5%34445%29%
2267
16th to endNight
17%15%6%7%5%35%34426%
1893
March1st to 15thNight
18%9%35%5%345%5%6%32%
2005
16th to endNight
19%9%36%325%45%6%34%
2112
April1st to 15thNight
16%8%25%5%3447%7%35%
1889
16th to endNight
14%5%346%245%5%7%40%
1620
May1st to 15thNight
17%7%35%5%25%5%5%8%33%
1620
16th to endNight
10%5%25%5%3436%8%43%
1682
June1st to 15thNight
6%3145%25%6%7%10%45%
1620
16th to endNight
10%3244345%6%8%45%
1620
July1st to 15thNight
10%5%25%5%245%5%8%42%
1620
16th to endNight
7%3235%35%6%6%8%46%
1703
August1st to 15thNight
5%4245%346%7%8%46%
1620
16th to endNight
8%425%32435%7%52%
1734
September1st to 15thNight
11%31341345%6%52%
1965
16th to endNight
12%5%24424446%48%
1980
October1st to 15thNight
12%5%245%23448%46%
1989
16th to endNight
19%7%2343445%5%38%
2112
November1st to 15thNight
16%6%23423336%48%
2265
16th to endNight
19%10%36%424345%32%
2340
December1st to 15thNight
23%12%5%7%5%25%345%23%
2340
16th to endNight
21%15%6%7%5%33445%21%
2496

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
21%14%7%9%6%3343421%
1611
16th to endDay
18%15%7%9%5%3434422%
1728
February1st to 15thDay
20%12%6%8%5%23335%26%
1591
16th to endDay
16%16%6%9%423335%28%
1580
March1st to 15thDay
21%12%46%5%23336%30%
1941
16th to endDay
20%8%47%5%25%346%32%
2111
April1st to 15thDay
19%9%35%5%3325%6%35%
2069
16th to endDay
16%7%36%5%2445%6%37%
2340
May1st to 15thDay
20%8%37%5%35%45%7%28%
2331
16th to endDay
11%5%35%6%35%5%6%8%37%
2431
June1st to 15thDay
11%5%246%45%5%6%10%37%
2340
16th to endDay
12%5%35%6%46%6%7%9%32%
2340
July1st to 15thDay
14%6%26%5%47%6%6%9%31%
2340
16th to endDay
10%435%5%47%6%7%9%34%
2465
August1st to 15thDay
8%5%36%5%46%7%8%11%32%
2340
16th to endDay
8%435%5%36%5%5%9%41%
2456
September1st to 15thDay
15%42442445%6%44%
1992
16th to endDay
16%6%25%424345%42%
1980
October1st to 15thDay
14%6%26%5%2445%7%40%
1768
16th to endDay
21%7%25%324335%40%
1760
November1st to 15thDay
12%7%35%423347%46%
1590
16th to endDay
19%11%36%5%3335%5%32%
1620
December1st to 15thDay
24%14%7%8%42434422%
1620
16th to endDay
22%17%5%8%5%23346%21%
1728
January1st to 15thNight
22%13%7%9%6%3433321%
2327
16th to endNight
17%13%5%8%6%33445%27%
2496
February1st to 15thNight
20%11%46%5%34445%29%
2260
16th to endNight
17%15%6%8%6%25%34426%
1893
March1st to 15thNight
18%9%36%5%3445%6%32%
2017
16th to endNight
19%9%35%424445%35%
2112
April1st to 15thNight
16%8%25%5%3436%7%35%
1889
16th to endNight
13%6%25%5%235%5%8%40%
1620
May1st to 15thNight
17%6%46%435%5%48%33%
1619
16th to endNight
10%5%25%5%3446%8%43%
1682
June1st to 15thNight
6%314435%6%7%10%45%
1620
16th to endNight
9%42443446%9%45%
1620
July1st to 15thNight
10%5%25%6%3446%8%42%
1620
16th to endNight
7%3235%26%6%6%8%47%
1703
August1st to 15thNight
5%4245%35%5%7%8%46%
1620
16th to endNight
8%315%42345%7%52%
1734
September1st to 15thNight
11%31432345%7%51%
1965
16th to endNight
12%5%24424446%47%
1980
October1st to 15thNight
12%4245%23447%47%
1989
16th to endNight
20%6%2443445%5%39%
2112
November1st to 15thNight
16%5%33423346%47%
2265
16th to endNight
19%9%35%5%34346%33%
2340
December1st to 15thNight
23%12%5%7%5%35%345%23%
2340
16th to endNight
21%15%5%7%5%34445%22%
2496

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
66%47%14%5%
1612
16th to endDay
65%311%14%4
1728
February1st to 15thDay
60%213%14%7%
1593
16th to endDay
58%311%19%6%
1580
March1st to 15thDay
56%310%21%6%1
1941
16th to endDay
53%5%9%21%9%
2112
April1st to 15thDay
50%39%20%12%2
2069
16th to endDay
46%410%19%13%4
2340
May1st to 15thDay
53%6%11%16%8%2
2331
16th to endDay
41%8%12%22%13%1
2435
June1st to 15thDay
40%7%12%22%15%1
2340
16th to endDay
44%8%12%17%15%1
2340
July1st to 15thDay
47%8%10%18%13%1
2201
16th to endDay
39%8%14%23%12%1
2310
August1st to 15thDay
41%8%12%21%13%1
2327
16th to endDay
36%6%12%25%14%4
2456
September1st to 15thDay
38%5%10%21%20%3
1992
16th to endDay
42%47%22%21%
1980
October1st to 15thDay
42%412%22%17%
1768
16th to endDay
46%311%25%11%1
1760
November1st to 15thDay
39%38%25%16%5%
1590
16th to endDay
53%310%20%11%
1620
December1st to 15thDay
66%210%14%5%
1620
16th to endDay
64%410%15%4
1728
January1st to 15thNight
67%38%12%6%
2327
16th to endNight
58%312%18%5%1
2496
February1st to 15thNight
57%311%18%7%
2269
16th to endNight
61%39%18%6%
1893
March1st to 15thNight
52%410%22%9%1
2017
16th to endNight
49%411%20%11%1
2112
April1st to 15thNight
46%411%19%15%1
1889
16th to endNight
41%5%10%20%17%5%
1620
May1st to 15thNight
48%6%12%19%10%2
1620
16th to endNight
37%6%15%24%14%2
1684
June1st to 15thNight
31%8%15%24%18%1
1620
16th to endNight
34%7%14%22%19%2
1620
July1st to 15thNight
39%6%9%21%19%2
1530
16th to endNight
31%8%15%25%17%1
1595
August1st to 15thNight
31%7%12%27%19%1
1609
16th to endNight
29%6%12%26%18%5%
1734
September1st to 15thNight
30%6%11%20%24%5%
1965
16th to endNight
36%5%7%23%25%1
1980
October1st to 15thNight
35%5%11%24%20%2
1989
16th to endNight
45%49%25%14%1
2112
November1st to 15thNight
37%311%22%19%5%
2265
16th to endNight
52%211%19%11%1
2340
December1st to 15thNight
62%410%15%6%
2340
16th to endNight
64%412%14%4
2496

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
35%20%32%6%41
90
16th to endDay
38%30%20%9%1
96
February1st to 15thDay
34%31%27%6%
90
16th to endDay
27%18%45%7%1
81
March1st to 15thDay
30%12%29%21%6%
231
16th to endDay
25%15%35%13%8%1
288
April1st to 15thDay
25%14%28%21%8%1
270
16th to endDay
20%12%31%17%11%5%
270
May1st to 15thDay
28%15%23%17%9%5%
288
16th to endDay
18%6%30%21%13%9%
331
June1st to 15thDay
13%7%20%32%17%7%
315
16th to endDay
16%9%26%24%14%8%
315
July1st to 15thDay
20%322%23%18%10%
305
16th to endDay
12%215%26%24%18%
326
August1st to 15thDay
12%215%27%24%16%
313
16th to endDay
10%316%30%22%16%
332
September1st to 15thDay
17%416%20%24%16%
315
16th to endDay
19%5%16%18%29%11%
314
October1st to 15thDay
11%8%25%24%24%6%
278
16th to endDay
23%11%30%20%12%
272
November1st to 15thDay
15%12%18%32%16%5%
98
16th to endDay
32%18%30%13%41
90
December1st to 15thDay
34%23%24%10%43
90
16th to endDay
37%21%33%6%1
96
January1st to 15thNight
32%18%28%18%2
720
16th to endNight
27%18%30%20%2
768
February1st to 15thNight
28%15%29%25%
704
16th to endNight
27%17%33%19%1
631
March1st to 15thNight
26%13%29%25%5%
720
16th to endNight
24%13%30%21%8%1
768
April1st to 15thNight
22%16%32%21%7%
688
16th to endNight
17%9%33%28%10%1
540
May1st to 15thNight
19%10%25%30%11%2
540
16th to endNight
13%5%20%31%25%3
563
June1st to 15thNight
7%224%39%24%1
540
16th to endNight
11%321%37%25%2
540
July1st to 15thNight
12%217%35%28%3
510
16th to endNight
9%115%31%36%5%
564
August1st to 15thNight
7%114%37%36%4
539
16th to endNight
8%114%31%37%5%
588
September1st to 15thNight
14%313%32%30%5%
720
16th to endNight
15%415%26%31%6%
717
October1st to 15thNight
14%5%21%30%23%3
684
16th to endNight
23%12%26%27%10%
704
November1st to 15thNight
20%9%23%28%16%1
700
16th to endNight
26%13%24%25%7%1
720
December1st to 15thNight
32%14%26%19%7%
720
16th to endNight
30%16%29%21%2
768
Page generated at 2017-10-07 14:07:47. Version ac04

Copyright 2017 A. Danko


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