Cooper Lake State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cooper Lake State Park clear sky chart from 2005-11-05 to 2018-01-12.

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
52%
16103
28%
48331
20%
16058
60%
16058
37%
27190

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
40%
954
28%
2472
12%
951
49%
951
38%
1488
January16th to endNight
36%
960
31%
2496
12%
960
47%
960
38%
1501
February1st to 15thNight
36%
830
26%
2238
10%
826
46%
826
34%
1362
February16th to endNight
30%
572
30%
1834
11%
572
44%
572
30%
1037
March1st to 15thNight
36%
540
27%
1980
17%
540
50%
540
25%
1149
March16th to endNight
39%
576
23%
2112
16%
576
50%
576
27%
1197
April1st to 15thNight
34%
539
25%
1923
14%
539
50%
539
32%
1016
April16th to endNight
40%
540
24%
1776
18%
540
53%
540
32%
982
May1st to 15thNight
42%
540
23%
1620
15%
540
54%
540
32%
966
May16th to endNight
55%
563
25%
1684
23%
561
63%
561
37%
970
June1st to 15thNight
74%
540
25%
1620
26%
540
78%
540
49%
818
June16th to endNight
76%
540
26%
1620
29%
540
78%
540
44%
865
July1st to 15thNight
78%
510
22%
1530
26%
510
80%
510
42%
834
July16th to endNight
87%
564
29%
1594
36%
531
88%
531
53%
798
August1st to 15thNight
89%
539
35%
1610
41%
536
89%
536
57%
762
August16th to endNight
78%
573
25%
1848
30%
573
78%
573
33%
1076
September1st to 15thNight
72%
540
23%
1968
29%
540
73%
540
33%
1055
September16th to endNight
75%
537
35%
1980
38%
537
78%
537
39%
971
October1st to 15thNight
63%
664
33%
2104
26%
664
67%
664
43%
1072
October16th to endNight
54%
768
38%
2304
23%
768
65%
768
48%
1151
November1st to 15thNight
51%
760
29%
2280
19%
760
60%
760
40%
1246
November16th to endNight
43%
939
33%
2499
17%
939
53%
939
38%
1481
December1st to 15thNight
40%
975
28%
2535
14%
975
48%
975
33%
1620
December16th to endNight
36%
1040
25%
2704
11%
1040
44%
1040
31%
1773

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
11%42442445%7%48%
49001
Night
10%413323347%54%
48527
TransparencyDay
35%5%10%22%20%5%
48701
Night
29%410%23%23%9%
48332
SeeingDay
11%418%27%28%9%
5969
Night
12%5%25%33%20%2
16105

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 15thDay
13%5%2321323456%
1710
16th to endDay
17%5%2231233452%
1728
February1st to 15thDay
18%6%14313335%48%
1633
16th to endDay
18%5%25%212235%49%
1640
March1st to 15thDay
19%6%24312335%46%
1980
16th to endDay
15%6%25%5%23345%43%
2110
April1st to 15thDay
13%415%424346%48%
2024
16th to endDay
14%42442446%7%44%
2181
May1st to 15thDay
14%6%36%425%5%45%42%
2331
16th to endDay
9%6%35%5%35%5%6%7%39%
2430
June1st to 15thDay
5%4245%35%5%6%8%48%
2340
16th to endDay
5%434425%5%7%9%48%
2340
July1st to 15thDay
6%335%6%36%6%7%10%40%
2340
16th to endDay
5%223446%6%6%11%45%
2466
August1st to 15thDay
42133245%6%10%55%
2340
16th to endDay
7%5%25%6%46%5%7%10%39%
2354
September1st to 15thDay
11%4245%25%446%46%
1989
16th to endDay
8%31333445%7%54%
1980
October1st to 15thDay
11%423413335%55%
1842
16th to endDay
9%33213335%64%
1920
November1st to 15thDay
10%424423436%52%
1908
16th to endDay
13%413223235%58%
1788
December1st to 15thDay
16%7%2432324447%
1755
16th to endDay
18%7%34312336%45%
1872
January1st to 15thNight
13%43213345%55%
2472
16th to endNight
14%5%1232224456%
2496
February1st to 15thNight
13%5%2331332455%
2228
16th to endNight
14%5%2321334355%
1834
March1st to 15thNight
17%5%24323336%48%
1980
16th to endNight
11%5%34323446%50%
2112
April1st to 15thNight
9%32342345%8%53%
1923
16th to endNight
11%413324238%53%
1776
May1st to 15thNight
10%5%2442435%8%49%
1619
16th to endNight
6%324425%5%7%10%48%
1683
June1st to 15thNight
331222335%9%62%
1620
16th to endNight
331233345%9%59%
1620
July1st to 15thNight
42243235%6%12%51%
1620
16th to endNight
311222446%12%59%
1702
August1st to 15thNight
211211245%10%64%
1620
16th to endNight
5%325%5%35%6%7%9%46%
1848
September1st to 15thNight
9%31432345%8%52%
1968
16th to endNight
6%214323347%59%
1980
October1st to 15thNight
10%312222246%61%
2104
16th to endNight
10%2211223466%
2304
November1st to 15thNight
8%32332334459%
2280
16th to endNight
12%424323235%56%
2499
December1st to 15thNight
14%6%24313345%50%
2535
16th to endNight
16%7%23323346%45%
2704

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
33%38%21%27%6%
1711
16th to endDay
36%35%21%26%7%
1728
February1st to 15thDay
41%35%21%22%6%
1634
16th to endDay
39%26%20%22%8%
1640
March1st to 15thDay
41%38%19%20%6%
1980
16th to endDay
43%48%19%20%4
2112
April1st to 15thDay
37%5%8%22%17%8%
2024
16th to endDay
38%6%9%18%22%4
2181
May1st to 15thDay
42%6%8%16%19%6%
2331
16th to endDay
41%7%11%21%15%1
2434
June1st to 15thDay
31%7%13%28%17%2
2340
16th to endDay
30%6%14%25%20%2
2340
July1st to 15thDay
34%7%15%29%12%
2201
16th to endDay
28%8%19%27%14%
2311
August1st to 15thDay
22%6%15%32%20%2
2326
16th to endDay
37%9%17%22%11%2
2354
September1st to 15thDay
37%5%10%20%17%7%
1989
16th to endDay
28%5%11%21%25%8%
1980
October1st to 15thDay
33%310%18%19%14%
1842
16th to endDay
24%27%19%32%14%
1920
November1st to 15thDay
33%38%24%21%7%
1908
16th to endDay
30%35%17%33%9%
1788
December1st to 15thDay
40%37%18%21%7%
1755
16th to endDay
42%36%23%18%5%
1872
January1st to 15thNight
31%38%17%28%9%
2472
16th to endNight
31%37%18%27%11%
2496
February1st to 15thNight
34%36%21%22%11%
2238
16th to endNight
33%38%20%22%11%
1834
March1st to 15thNight
38%38%19%19%10%
1980
16th to endNight
34%5%10%19%23%5%
2112
April1st to 15thNight
28%5%12%22%18%12%
1923
16th to endNight
31%410%20%24%8%
1776
May1st to 15thNight
33%5%12%19%19%9%
1620
16th to endNight
29%6%17%26%16%3
1685
June1st to 15thNight
19%5%11%34%23%4
1620
16th to endNight
22%7%11%28%25%5%
1620
July1st to 15thNight
24%6%13%35%18%1
1530
16th to endNight
15%7%18%34%21%2
1594
August1st to 15thNight
15%414%34%24%5%
1610
16th to endNight
32%6%13%28%15%3
1848
September1st to 15thNight
30%410%22%21%9%
1968
16th to endNight
25%47%23%27%11%
1980
October1st to 15thNight
25%310%22%21%16%
2104
16th to endNight
22%15%18%30%21%
2304
November1st to 15thNight
28%39%22%25%11%
2280
16th to endNight
32%25%16%31%11%
2499
December1st to 15thNight
37%48%19%20%9%
2535
16th to endNight
40%38%20%19%7%
2704

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
15%9%35%27%11%
123
16th to endDay
16%10%42%19%8%2
96
February1st to 15thDay
18%14%37%21%7%
90
16th to endDay
22%9%44%18%22
81
March1st to 15thDay
24%17%34%15%6%1
90
16th to endDay
10%15%35%27%9%2
96
April1st to 15thDay
18%10%25%30%13%
143
16th to endDay
20%8%29%25%14%1
291
May1st to 15thDay
16%8%34%27%10%3
468
16th to endDay
15%5%26%31%19%2
517
June1st to 15thDay
7%111%35%32%10%
495
16th to endDay
7%111%32%36%11%
495
July1st to 15thDay
6%11%34%37%9%
475
16th to endDay
3321%51%19%
515
August1st to 15thDay
5%325%49%15%
493
16th to endDay
11%6%23%37%19%
394
September1st to 15thDay
26%15%46%29%
144
16th to endDay
5%325%44%20%
135
October1st to 15thDay
5%115%30%31%15%
135
16th to endDay
10%6%15%38%22%5%
144
November1st to 15thDay
22%126%29%14%4
135
16th to endDay
22%7%28%25%12%2
135
December1st to 15thDay
25%431%23%11%3
135
16th to endDay
25%13%32%23%4
144
January1st to 15thNight
16%9%31%33%9%
956
16th to endNight
16%9%35%31%7%
960
February1st to 15thNight
16%9%35%32%7%
830
16th to endNight
17%12%38%28%3
572
March1st to 15thNight
20%8%31%31%7%
540
16th to endNight
12%9%35%34%7%
576
April1st to 15thNight
11%9%43%25%9%
539
16th to endNight
11%7%36%32%9%1
540
May1st to 15thNight
11%5%35%35%10%1
540
16th to endNight
7%326%38%20%2
563
June1st to 15thNight
5%112%44%33%2
540
16th to endNight
4112%38%37%5%
540
July1st to 15thNight
48%40%41%4
510
16th to endNight
3330%51%10%
564
August1st to 15thNight
4331%52%8%
539
16th to endNight
8%332%46%8%
573
September1st to 15thNight
12%7%28%45%5%
540
16th to endNight
7%9%34%42%5%
537
October1st to 15thNight
12%18%34%29%3
664
16th to endNight
11%427%33%20%2
768
November1st to 15thNight
10%5%28%36%17%1
760
16th to endNight
14%7%31%31%13%
939
December1st to 15thNight
18%6%30%35%8%
975
16th to endNight
20%8%31%31%8%
1040
Page generated at 2018-01-12 21:01:38. Version ac04

Copyright 2018 A. Danko


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