Storm Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Storm Lake clear sky chart from 2005-11-05 to 2018-10-27.

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%
17536
19%
51324
11%
17490
45%
17490
28%
32473

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
29%
975
16%
2605
6%
970
38%
970
25%
1758
January16th to endNight
25%
1040
18%
2704
6%
1040
34%
1040
22%
1922
February1st to 15thNight
23%
955
12%
2483
2%
951
29%
951
20%
1823
February16th to endNight
28%
796
20%
2162
6%
796
38%
796
28%
1430
March1st to 15thNight
37%
586
20%
2146
15%
586
46%
586
23%
1291
March16th to endNight
26%
624
13%
2288
10%
624
34%
624
15%
1595
April1st to 15thNight
27%
584
16%
1999
11%
584
38%
584
22%
1260
April16th to endNight
32%
579
17%
1746
11%
579
42%
579
22%
1200
May1st to 15thNight
39%
585
18%
1755
12%
585
46%
585
27%
1126
May16th to endNight
44%
610
16%
1644
8%
609
49%
609
30%
1062
June1st to 15thNight
49%
585
16%
1560
6%
585
53%
585
33%
997
June16th to endNight
56%
585
19%
1560
8%
585
60%
585
44%
886
July1st to 15thNight
67%
555
20%
1488
9%
555
70%
555
51%
802
July16th to endNight
74%
612
22%
1738
19%
579
75%
579
54%
835
August1st to 15thNight
66%
575
22%
1717
21%
572
70%
572
40%
949
August16th to endNight
59%
621
22%
1908
23%
621
64%
621
36%
1076
September1st to 15thNight
58%
585
26%
2002
24%
585
66%
585
37%
1055
September16th to endNight
48%
582
26%
2145
21%
582
59%
582
33%
1131
October1st to 15thNight
35%
770
24%
2330
14%
770
43%
770
28%
1427
October16th to endNight
37%
816
23%
2448
12%
816
46%
816
29%
1464
November1st to 15thNight
35%
926
23%
2524
11%
926
45%
926
31%
1567
November16th to endNight
29%
975
20%
2730
9%
975
38%
975
28%
1745
December1st to 15thNight
25%
975
13%
2730
4%
975
33%
975
21%
1919
December16th to endNight
22%
1040
16%
2912
6%
1040
31%
1040
17%
2153

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
13%7%35%5%3445%7%40%
52225
Night
11%6%35%424347%45%
51505
Cloud CoverDay
13%7%35%5%3445%7%40%
52236
Night
11%6%25%424447%45%
51509
Cloud CoverDay
13%7%35%5%3445%7%40%
52234
Night
11%6%35%424447%45%
51509
TransparencyDay
42%5%14%23%12%1
51924
Night
38%5%14%24%14%2
51324
SeeingDay
15%7%29%29%14%3
7530
Night
14%8%33%31%11%
17537

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
7%11%48%7%45%45%6%33%
1661
16th to endDay
11%9%5%10%6%345%5%7%29%
1872
February1st to 15thDay
12%11%5%8%7%4345%6%29%
1710
16th to endDay
13%8%37%6%35%446%36%
1607
March1st to 15thDay
12%11%48%424346%36%
2131
16th to endDay
20%11%46%5%33446%29%
2288
April1st to 15thDay
16%9%36%5%3435%7%35%
2279
16th to endDay
26%6%35%5%23346%32%
2488
May1st to 15thDay
19%7%36%42346%7%34%
2526
16th to endDay
15%6%25%5%34347%40%
2823
June1st to 15thDay
14%6%24445%5%6%7%39%
2730
16th to endDay
9%4145%35%46%9%46%
2730
July1st to 15thDay
7%3144245%5%9%50%
2720
16th to endDay
5%3145%25%5%6%9%50%
2674
August1st to 15thDay
10%5%2442446%8%44%
2486
16th to endDay
11%5%25%43445%7%46%
2646
September1st to 15thDay
12%41432445%6%50%
2285
16th to endDay
13%323323346%53%
2142
October1st to 15thDay
17%6%24423335%45%
1950
16th to endDay
14%6%24323345%47%
2033
November1st to 15thDay
9%6%2442445%6%47%
1660
16th to endDay
13%8%35%423448%40%
1560
December1st to 15thDay
13%9%48%7%345%46%30%
1560
16th to endDay
13%12%6%8%7%445%5%5%25%
1664
January1st to 15thNight
8%7%37%6%35%5%5%8%38%
2605
16th to endNight
11%8%5%6%7%345%5%7%35%
2704
February1st to 15thNight
12%10%6%8%6%33345%35%
2480
16th to endNight
9%7%36%5%2435%6%43%
2162
March1st to 15thNight
12%6%25%42335%8%44%
2134
16th to endNight
14%11%47%5%34345%34%
2288
April1st to 15thNight
15%7%245%3445%6%41%
1999
16th to endNight
17%7%26%424346%39%
1746
May1st to 15thNight
15%5%25%32335%7%45%
1755
16th to endNight
12%5%235%3445%9%43%
1642
June1st to 15thNight
8%435%5%35%45%8%46%
1560
16th to endNight
5%223425%45%8%56%
1560
July1st to 15thNight
321232446%8%61%
1568
16th to endNight
311231337%10%61%
1846
August1st to 15thNight
5%22442445%7%56%
1727
16th to endNight
8%414423246%56%
1908
September1st to 15thNight
9%323323345%58%
2002
16th to endNight
10%414323346%55%
2145
October1st to 15thNight
15%6%24323245%49%
2330
16th to endNight
13%7%14322336%51%
2448
November1st to 15thNight
10%6%24424437%49%
2524
16th to endNight
11%6%26%42345%6%46%
2730
December1st to 15thNight
11%11%47%5%25%446%36%
2730
16th to endNight
16%10%5%7%7%24346%31%
2912

Percentage Cloud Cover SW (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
7%11%48%8%45%45%6%33%
1661
16th to endDay
11%10%5%10%6%3445%7%29%
1872
February1st to 15thDay
12%11%5%8%7%4445%6%29%
1710
16th to endDay
13%9%37%5%35%446%36%
1607
March1st to 15thDay
12%11%48%5%33346%36%
2142
16th to endDay
19%12%46%5%33446%29%
2288
April1st to 15thDay
16%9%36%5%3435%7%35%
2279
16th to endDay
25%7%35%423346%32%
2488
May1st to 15thDay
18%7%36%42446%7%34%
2526
16th to endDay
15%6%345%34447%40%
2823
June1st to 15thDay
14%6%24435%5%6%8%39%
2730
16th to endDay
8%4145%345%6%9%46%
2730
July1st to 15thDay
7%3144245%5%9%50%
2720
16th to endDay
5%314435%5%6%9%50%
2674
August1st to 15thDay
10%5%25%42446%8%44%
2486
16th to endDay
11%5%24434447%46%
2646
September1st to 15thDay
12%5%1432445%6%50%
2285
16th to endDay
13%313323346%53%
2142
October1st to 15thDay
16%6%24423335%45%
1950
16th to endDay
14%6%24324345%47%
2033
November1st to 15thDay
9%6%2442445%6%47%
1660
16th to endDay
13%8%35%5%24448%41%
1560
December1st to 15thDay
13%9%49%7%35%5%5%6%30%
1560
16th to endDay
13%12%7%8%7%445%5%6%25%
1664
January1st to 15thNight
8%7%37%6%35%5%5%8%38%
2605
16th to endNight
11%8%47%6%3445%7%35%
2704
February1st to 15thNight
12%11%5%8%6%3334435%
2473
16th to endNight
9%7%36%5%2445%6%43%
2162
March1st to 15thNight
13%6%25%42435%8%43%
2146
16th to endNight
14%12%47%5%24335%34%
2288
April1st to 15thNight
15%8%2442445%6%41%
1999
16th to endNight
17%7%26%5%23345%39%
1746
May1st to 15thNight
14%5%24423348%44%
1754
16th to endNight
12%5%245%2346%8%43%
1642
June1st to 15thNight
8%5%245%3445%8%45%
1560
16th to endNight
4223425%45%9%56%
1560
July1st to 15thNight
321232346%8%61%
1568
16th to endNight
311221337%10%61%
1846
August1st to 15thNight
5%21442345%7%56%
1727
16th to endNight
9%314423346%55%
1908
September1st to 15thNight
9%31331335%6%58%
2002
16th to endNight
10%414323346%55%
2145
October1st to 15thNight
15%6%14323335%49%
2330
16th to endNight
13%6%24322336%51%
2448
November1st to 15thNight
10%6%24324437%49%
2524
16th to endNight
11%6%26%423446%46%
2730
December1st to 15thNight
11%11%37%5%25%346%36%
2730
16th to endNight
16%10%5%8%7%24346%31%
2912

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
7%11%48%7%45%45%6%33%
1661
16th to endDay
11%9%5%10%7%345%46%29%
1872
February1st to 15thDay
12%12%48%7%44446%29%
1710
16th to endDay
13%8%38%5%35%45%5%35%
1607
March1st to 15thDay
12%12%47%5%24345%36%
2142
16th to endDay
19%11%36%5%24346%29%
2286
April1st to 15thDay
16%8%36%5%3335%8%35%
2279
16th to endDay
25%7%35%5%23345%33%
2488
May1st to 15thDay
19%7%35%43346%7%34%
2526
16th to endDay
16%6%25%6%24348%40%
2823
June1st to 15thDay
14%5%244445%5%8%38%
2730
16th to endDay
8%4245%35%46%9%46%
2730
July1st to 15thDay
7%3144245%6%9%50%
2720
16th to endDay
5%314435%5%6%9%50%
2674
August1st to 15thDay
9%5%25%435%46%8%44%
2486
16th to endDay
11%5%25%424447%46%
2646
September1st to 15thDay
12%41432445%6%49%
2285
16th to endDay
13%313323446%53%
2142
October1st to 15thDay
17%6%24423335%45%
1950
16th to endDay
14%7%24323345%47%
2033
November1st to 15thDay
9%6%34424447%47%
1660
16th to endDay
13%8%35%5%2345%7%41%
1560
December1st to 15thDay
14%8%48%8%35%5%46%30%
1560
16th to endDay
14%12%6%8%7%45%45%5%25%
1664
January1st to 15thNight
8%7%36%6%35%5%5%8%37%
2605
16th to endNight
11%8%46%6%3445%7%35%
2704
February1st to 15thNight
12%11%6%8%5%33345%35%
2473
16th to endNight
9%8%36%42435%7%43%
2162
March1st to 15thNight
12%6%3442335%8%43%
2146
16th to endNight
14%11%5%7%5%34346%34%
2288
April1st to 15thNight
15%7%24424347%41%
1999
16th to endNight
17%8%26%5%23345%39%
1746
May1st to 15thNight
15%5%24432347%45%
1754
16th to endNight
11%6%2442436%9%43%
1642
June1st to 15thNight
8%5%25%5%25%45%8%46%
1560
16th to endNight
5%2134245%5%8%56%
1560
July1st to 15thNight
321232445%9%61%
1568
16th to endNight
311222337%10%61%
1846
August1st to 15thNight
5%215%425%35%7%56%
1727
16th to endNight
8%414423346%56%
1908
September1st to 15thNight
9%32332335%6%57%
2002
16th to endNight
10%413323347%54%
2145
October1st to 15thNight
15%5%24423245%49%
2330
16th to endNight
13%6%24322336%51%
2448
November1st to 15thNight
10%6%24424437%49%
2524
16th to endNight
11%7%35%42345%6%46%
2730
December1st to 15thNight
11%11%46%6%24446%36%
2730
16th to endNight
16%10%48%7%24346%31%
2912

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
49%5%14%20%8%
1662
16th to endDay
53%5%15%19%5%
1872
February1st to 15thDay
55%313%18%8%
1711
16th to endDay
48%5%13%20%9%1
1607
March1st to 15thDay
48%5%13%21%9%1
2142
16th to endDay
55%6%14%17%5%
2288
April1st to 15thDay
49%413%23%7%1
2279
16th to endDay
53%5%10%21%8%
2488
May1st to 15thDay
48%5%14%21%9%
2526
16th to endDay
43%6%13%21%13%
2827
June1st to 15thDay
41%7%14%23%12%1
2730
16th to endDay
32%7%16%27%12%2
2730
July1st to 15thDay
30%7%16%28%13%3
2571
16th to endDay
27%7%15%28%17%2
2519
August1st to 15thDay
36%7%14%27%12%1
2472
16th to endDay
36%6%11%26%15%3
2646
September1st to 15thDay
34%5%12%27%18%1
2285
16th to endDay
31%414%30%18%
2142
October1st to 15thDay
41%410%24%17%1
1950
16th to endDay
39%412%26%15%2
2033
November1st to 15thDay
35%414%25%19%
1660
16th to endDay
42%417%23%12%
1560
December1st to 15thDay
53%6%15%15%6%1
1560
16th to endDay
59%412%15%6%1
1664
January1st to 15thNight
43%5%16%21%13%
2605
16th to endNight
47%5%15%21%8%
2704
February1st to 15thNight
52%412%20%8%1
2483
16th to endNight
40%5%14%23%14%2
2162
March1st to 15thNight
39%5%12%28%12%1
2146
16th to endNight
52%5%12%20%8%1
2288
April1st to 15thNight
42%412%25%13%1
1999
16th to endNight
47%5%12%20%12%1
1746
May1st to 15thNight
38%6%13%24%15%1
1755
16th to endNight
37%6%17%22%13%2
1644
June1st to 15thNight
35%6%15%25%13%2
1560
16th to endNight
25%6%15%29%20%3
1560
July1st to 15thNight
19%6%18%32%18%5%
1488
16th to endNight
16%5%19%34%20%3
1738
August1st to 15thNight
26%6%15%30%18%3
1717
16th to endNight
29%6%14%27%17%5%
1908
September1st to 15thNight
27%5%12%29%22%3
2002
16th to endNight
30%410%32%20%2
2145
October1st to 15thNight
38%410%23%20%3
2330
16th to endNight
35%413%25%19%1
2448
November1st to 15thNight
35%412%23%21%2
2524
16th to endNight
38%5%15%26%12%1
2730
December1st to 15thNight
49%415%22%8%
2730
16th to endNight
54%412%17%9%
2912

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
14%11%37%28%8%
135
16th to endDay
20%6%38%26%5%2
144
February1st to 15thDay
15%17%40%24%2
135
16th to endDay
22%15%30%23%8%
120
March1st to 15thDay
20%12%44%17%5%
135
16th to endDay
38%9%27%18%6%
144
April1st to 15thDay
22%10%33%27%6%
278
16th to endDay
29%12%27%18%10%2
500
May1st to 15thDay
23%11%28%24%9%1
543
16th to endDay
16%6%32%25%14%4
597
June1st to 15thDay
12%7%26%34%15%2
570
16th to endDay
9%433%33%15%2
570
July1st to 15thDay
7%224%35%22%7%
550
16th to endDay
5%221%42%23%4
595
August1st to 15thDay
10%219%38%25%4
549
16th to endDay
12%421%32%21%7%
558
September1st to 15thDay
12%327%35%15%5%
320
16th to endDay
16%8%29%31%13%
180
October1st to 15thDay
23%9%35%21%7%1
180
16th to endDay
16%9%39%24%10%
178
November1st to 15thDay
7%11%36%32%8%2
135
16th to endDay
28%10%37%20%2
135
December1st to 15thDay
17%17%42%18%3
135
16th to endDay
25%14%44%14%
144
January1st to 15thNight
12%12%38%28%7%1
975
16th to endNight
16%9%40%28%5%
1040
February1st to 15thNight
17%10%39%25%5%
955
16th to endNight
12%10%41%26%7%1
796
March1st to 15thNight
15%8%35%29%9%
586
16th to endNight
18%12%36%24%8%
624
April1st to 15thNight
20%10%36%27%4
584
16th to endNight
21%9%33%24%10%1
579
May1st to 15thNight
15%10%30%32%10%
585
16th to endNight
14%6%28%36%12%
611
June1st to 15thNight
11%429%41%13%
585
16th to endNight
6%329%47%13%
585
July1st to 15thNight
5%122%44%25%1
555
16th to endNight
316%52%24%1
612
August1st to 15thNight
6%118%44%26%2
575
16th to endNight
9%220%39%22%5%
621
September1st to 15thNight
11%124%39%21%2
585
16th to endNight
10%5%31%34%16%1
582
October1st to 15thNight
18%9%33%27%10%
770
16th to endNight
17%10%30%31%8%
816
November1st to 15thNight
13%11%35%28%9%1
926
16th to endNight
14%11%40%24%8%
975
December1st to 15thNight
17%11%39%26%4
975
16th to endNight
20%9%37%25%6%
1040
Page generated at 2018-10-28 07:41:03. Version ac04

Copyright 2018 A. Danko


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