Estherville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Estherville clear sky chart from 2005-11-05 to 2017-09-23.

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
37%
16094
18%
46892
10%
16047
44%
16047
26%
30326

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
28%
900
14%
2447
6%
895
35%
895
21%
1725
January16th to endNight
24%
960
15%
2496
5%
960
32%
960
19%
1830
February1st to 15thNight
23%
879
12%
2288
2%
875
29%
875
20%
1686
February16th to endNight
27%
755
18%
2017
5%
755
37%
755
24%
1376
March1st to 15thNight
34%
540
18%
1980
11%
540
45%
540
23%
1221
March16th to endNight
28%
576
14%
2112
9%
576
36%
576
15%
1463
April1st to 15thNight
30%
539
16%
1830
11%
539
40%
539
22%
1181
April16th to endNight
27%
540
18%
1632
11%
540
38%
540
20%
1160
May1st to 15thNight
37%
540
17%
1596
10%
540
43%
540
26%
1045
May16th to endNight
41%
563
15%
1498
6%
561
47%
561
29%
1000
June1st to 15thNight
50%
540
14%
1440
5%
540
55%
540
33%
921
June16th to endNight
57%
540
20%
1361
7%
540
61%
540
47%
791
July1st to 15thNight
63%
510
18%
1357
7%
510
67%
510
50%
733
July16th to endNight
69%
564
23%
1550
17%
531
71%
531
49%
804
August1st to 15thNight
65%
539
23%
1610
21%
536
69%
536
41%
888
August16th to endNight
60%
573
24%
1764
25%
573
65%
573
38%
975
September1st to 15thNight
58%
540
25%
1827
22%
540
67%
540
40%
919
September16th to endNight
44%
519
26%
1906
18%
519
58%
519
32%
1030
October1st to 15thNight
38%
660
26%
1980
14%
660
47%
660
31%
1160
October16th to endNight
35%
704
19%
2112
10%
704
42%
704
26%
1329
November1st to 15thNight
33%
853
24%
2361
10%
853
44%
853
29%
1475
November16th to endNight
27%
900
17%
2520
8%
900
35%
900
23%
1697
December1st to 15thNight
22%
900
12%
2520
4%
900
29%
900
18%
1867
December16th to endNight
20%
960
14%
2688
5%
960
29%
960
15%
2050

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%36%5%3445%7%38%
47982
Night
11%7%35%42445%6%43%
47072
Cloud CoverDay
13%7%36%5%3445%7%38%
47993
Night
11%7%35%42445%6%43%
47076
Cloud CoverDay
13%7%36%5%3445%7%38%
47991
Night
11%7%35%42445%7%43%
47076
TransparencyDay
44%5%13%23%11%1
47680
Night
40%5%13%24%13%1
46892
SeeingDay
15%7%29%29%14%3
6099
Night
15%8%33%30%11%
16095

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
8%11%5%8%8%3446%7%30%
1489
16th to endDay
9%12%6%10%7%36%46%7%24%
1728
February1st to 15thDay
11%10%6%9%8%35%446%28%
1575
16th to endDay
12%8%48%7%35%5%47%31%
1467
March1st to 15thDay
13%10%6%8%5%34245%33%
1969
16th to endDay
18%11%45%5%35%45%6%29%
2112
April1st to 15thDay
17%7%36%5%2445%8%33%
2118
16th to endDay
25%11%35%423345%28%
2325
May1st to 15thDay
21%6%35%5%34346%35%
2355
16th to endDay
16%5%25%5%3445%7%38%
2617
June1st to 15thDay
15%5%245%3445%9%39%
2520
16th to endDay
8%414435%5%6%8%46%
2570
July1st to 15thDay
5%2145%26%5%6%9%49%
2520
16th to endDay
5%3143245%7%10%50%
2509
August1st to 15thDay
8%5%25%6%45%5%6%8%41%
2340
16th to endDay
10%5%245%245%5%6%45%
2438
September1st to 15thDay
12%3133345%5%7%49%
2130
16th to endDay
11%5%15%323346%51%
1879
October1st to 15thDay
12%7%24423345%48%
1650
16th to endDay
14%8%25%423345%43%
1760
November1st to 15thDay
9%6%26%42345%6%47%
1495
16th to endDay
12%9%5%5%6%34338%37%
1440
December1st to 15thDay
13%11%411%9%46%346%25%
1440
16th to endDay
17%13%5%9%7%24447%23%
1536
January1st to 15thNight
8%8%5%6%6%46%5%6%8%32%
2447
16th to endNight
10%11%47%5%45%5%5%7%31%
2496
February1st to 15thNight
11%12%6%7%5%2445%5%34%
2285
16th to endNight
9%7%36%6%35%446%39%
2017
March1st to 15thNight
12%7%36%423437%43%
1968
16th to endNight
16%10%47%5%25%345%34%
2112
April1st to 15thNight
15%6%26%5%24445%41%
1830
16th to endNight
20%8%36%434335%36%
1632
May1st to 15thNight
14%5%24434446%45%
1596
16th to endNight
13%5%25%425%5%6%9%40%
1496
June1st to 15thNight
9%3244346%7%9%43%
1440
16th to endNight
6%21331345%7%58%
1361
July1st to 15thNight
221322436%8%62%
1437
16th to endNight
211132446%10%60%
1657
August1st to 15thNight
5%3244235%5%8%55%
1620
16th to endNight
8%413323246%58%
1764
September1st to 15thNight
9%313313346%60%
1827
16th to endNight
8%42432435%7%53%
1906
October1st to 15thNight
14%5%1432323453%
1980
16th to endNight
15%7%2332345%5%46%
2112
November1st to 15thNight
11%6%25%433345%49%
2361
16th to endNight
11%8%46%5%24446%41%
2520
December1st to 15thNight
13%11%48%6%35%446%31%
2520
16th to endNight
18%10%5%8%7%34345%28%
2688

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
8%11%48%8%35%46%7%30%
1489
16th to endDay
10%12%6%9%8%45%46%6%24%
1728
February1st to 15thDay
11%10%6%10%7%44446%28%
1575
16th to endDay
12%8%48%7%35%5%47%32%
1467
March1st to 15thDay
13%10%6%8%43425%6%33%
1980
16th to endDay
18%11%45%5%3445%7%29%
2112
April1st to 15thDay
17%7%36%5%2446%7%33%
2118
16th to endDay
26%11%35%424345%28%
2325
May1st to 15thDay
21%6%26%5%34346%35%
2355
16th to endDay
17%426%435%45%7%38%
2617
June1st to 15thDay
15%5%25%5%3445%8%39%
2520
16th to endDay
8%423435%5%5%8%47%
2570
July1st to 15thDay
6%214436%5%5%10%49%
2520
16th to endDay
5%3144245%6%10%51%
2509
August1st to 15thDay
8%5%25%7%35%5%6%8%41%
2340
16th to endDay
11%5%25%4345%5%7%45%
2438
September1st to 15thDay
12%41343345%7%49%
2130
16th to endDay
12%424422346%51%
1879
October1st to 15thDay
12%7%24423435%48%
1650
16th to endDay
14%8%25%423346%43%
1760
November1st to 15thDay
9%6%25%5%24447%47%
1495
16th to endDay
12%9%45%5%34339%37%
1440
December1st to 15thDay
13%11%411%9%36%336%25%
1440
16th to endDay
17%12%5%8%7%34447%23%
1536
January1st to 15thNight
8%8%5%5%6%46%5%6%8%33%
2447
16th to endNight
10%11%48%5%45%5%6%7%31%
2496
February1st to 15thNight
11%12%5%8%5%2445%5%33%
2278
16th to endNight
10%7%36%6%345%5%7%39%
2017
March1st to 15thNight
13%7%36%423347%43%
1980
16th to endNight
15%11%46%5%35%245%35%
2112
April1st to 15thNight
16%6%26%424445%41%
1830
16th to endNight
20%9%35%424335%36%
1632
May1st to 15thNight
14%5%14434447%44%
1595
16th to endNight
13%5%244245%5%10%41%
1496
June1st to 15thNight
9%4244346%7%8%44%
1440
16th to endNight
6%21331445%7%58%
1361
July1st to 15thNight
321332336%9%62%
1437
16th to endNight
311232446%10%60%
1657
August1st to 15thNight
5%31442445%8%55%
1620
16th to endNight
8%413333245%58%
1764
September1st to 15thNight
9%313322336%60%
1827
16th to endNight
8%423324447%53%
1906
October1st to 15thNight
14%5%2432333453%
1980
16th to endNight
16%7%2332245%5%46%
2112
November1st to 15thNight
11%6%25%423345%49%
2361
16th to endNight
11%8%46%5%3445%6%41%
2520
December1st to 15thNight
12%11%47%6%35%446%31%
2520
16th to endNight
18%10%6%7%7%33446%28%
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
8%11%5%8%9%3446%7%29%
1489
16th to endDay
10%12%6%9%8%36%5%6%6%24%
1728
February1st to 15thDay
11%11%7%9%8%44446%28%
1575
16th to endDay
12%8%48%8%35%5%48%31%
1467
March1st to 15thDay
13%10%7%7%5%34246%33%
1980
16th to endDay
18%11%46%43445%7%29%
2110
April1st to 15thDay
16%7%37%5%2445%8%33%
2118
16th to endDay
25%11%35%423445%29%
2325
May1st to 15thDay
21%7%26%5%34346%35%
2355
16th to endDay
16%5%35%4345%47%38%
2617
June1st to 15thDay
15%5%25%5%3445%9%39%
2520
16th to endDay
8%414435%5%6%8%46%
2570
July1st to 15thDay
5%214436%5%5%10%49%
2520
16th to endDay
5%3144245%6%11%50%
2509
August1st to 15thDay
8%5%25%6%445%6%8%41%
2340
16th to endDay
10%5%25%425%5%5%6%45%
2438
September1st to 15thDay
11%42342445%7%49%
2130
16th to endDay
11%5%23423446%51%
1879
October1st to 15thDay
12%7%25%5%23345%48%
1650
16th to endDay
14%9%25%423336%43%
1760
November1st to 15thDay
9%6%25%42345%6%47%
1495
16th to endDay
13%9%5%5%6%34338%37%
1440
December1st to 15thDay
13%11%411%9%36%336%24%
1440
16th to endDay
17%13%5%8%7%3435%7%23%
1536
January1st to 15thNight
8%8%5%6%6%46%5%6%8%33%
2447
16th to endNight
10%11%48%5%445%5%7%31%
2496
February1st to 15thNight
11%12%5%7%5%2445%5%33%
2278
16th to endNight
9%7%46%6%345%47%39%
2017
March1st to 15thNight
12%7%37%423347%42%
1980
16th to endNight
15%11%47%5%34345%34%
2112
April1st to 15thNight
15%5%26%5%24445%41%
1830
16th to endNight
20%9%26%424335%36%
1632
May1st to 15thNight
14%5%24434446%44%
1595
16th to endNight
13%4244245%6%9%40%
1496
June1st to 15thNight
9%425%435%5%7%9%43%
1440
16th to endNight
5%21322435%8%58%
1361
July1st to 15thNight
321332335%9%62%
1437
16th to endNight
221231436%10%60%
1657
August1st to 15thNight
5%32442445%8%55%
1620
16th to endNight
8%413333245%58%
1764
September1st to 15thNight
8%313313346%59%
1827
16th to endNight
8%5%2332435%7%53%
1906
October1st to 15thNight
14%5%1332233453%
1980
16th to endNight
15%8%23313446%45%
2112
November1st to 15thNight
10%6%25%423345%49%
2361
16th to endNight
11%8%46%5%34446%40%
2520
December1st to 15thNight
13%11%47%6%4445%6%30%
2520
16th to endNight
18%10%6%7%7%33436%27%
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
51%5%13%18%10%
1490
16th to endDay
57%5%14%16%4
1728
February1st to 15thDay
56%5%12%18%6%
1576
16th to endDay
52%6%13%18%8%1
1467
March1st to 15thDay
52%414%21%6%
1980
16th to endDay
54%5%13%20%5%
2112
April1st to 15thDay
48%6%11%23%8%1
2118
16th to endDay
57%410%19%7%
2325
May1st to 15thDay
51%412%21%8%
2355
16th to endDay
45%5%13%21%12%1
2621
June1st to 15thDay
42%5%14%24%11%
2520
16th to endDay
33%6%15%27%14%2
2570
July1st to 15thDay
30%6%15%28%13%3
2371
16th to endDay
28%6%15%30%16%2
2353
August1st to 15thDay
39%7%13%27%11%1
2326
16th to endDay
37%6%11%27%14%2
2438
September1st to 15thDay
34%5%14%27%16%
2130
16th to endDay
33%5%12%33%14%
1879
October1st to 15thDay
38%411%23%19%1
1650
16th to endDay
43%414%25%12%
1760
November1st to 15thDay
37%412%24%19%1
1495
16th to endDay
47%416%20%10%
1440
December1st to 15thDay
61%411%13%7%1
1440
16th to endDay
61%410%16%6%
1536
January1st to 15thNight
46%6%13%21%11%
2447
16th to endNight
51%5%15%19%7%
2496
February1st to 15thNight
50%6%11%21%9%
2288
16th to endNight
44%5%13%22%12%2
2017
March1st to 15thNight
41%415%25%11%1
1980
16th to endNight
52%5%11%22%6%
2112
April1st to 15thNight
44%410%25%13%1
1830
16th to endNight
51%49%20%11%2
1632
May1st to 15thNight
39%7%12%24%14%1
1596
16th to endNight
39%7%14%23%13%2
1498
June1st to 15thNight
34%7%16%25%14%1
1440
16th to endNight
23%6%14%30%21%3
1361
July1st to 15thNight
20%5%17%33%18%4
1357
16th to endNight
19%6%16%33%19%4
1550
August1st to 15thNight
26%5%14%31%18%3
1610
16th to endNight
29%312%31%17%4
1764
September1st to 15thNight
25%314%30%22%2
1827
16th to endNight
30%411%32%18%1
1906
October1st to 15thNight
35%310%27%20%2
1980
16th to endNight
39%415%24%15%1
2112
November1st to 15thNight
37%411%23%20%2
2361
16th to endNight
44%415%21%11%1
2520
December1st to 15thNight
54%414%19%6%
2520
16th to endNight
58%410%15%9%
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
16%11%40%22%8%1
90
16th to endDay
17%10%37%29%41
96
February1st to 15thDay
14%23%34%24%3
90
16th to endDay
20%13%30%22%12%
81
March1st to 15thDay
25%17%31%23%2
90
16th to endDay
34%7%22%26%9%
96
April1st to 15thDay
21%8%35%27%7%
237
16th to endDay
31%14%25%18%7%2
435
May1st to 15thDay
22%11%28%28%5%2
468
16th to endDay
18%8%31%25%13%2
517
June1st to 15thDay
15%430%29%16%3
495
16th to endDay
8%6%35%32%13%3
495
July1st to 15thDay
6%229%33%22%5%
475
16th to endDay
8%224%38%21%4
515
August1st to 15thDay
9%120%38%25%4
493
16th to endDay
15%421%30%21%7%
478
September1st to 15thDay
11%326%35%20%3
285
16th to endDay
12%10%31%24%18%2
111
October1st to 15thDay
5%10%34%33%10%6%
90
16th to endDay
16%10%41%19%11%
96
November1st to 15thDay
37%38%31%15%3
90
16th to endDay
35%13%30%16%4
90
December1st to 15thDay
18%18%41%12%7%1
90
16th to endDay
32%19%32%12%3
96
January1st to 15thNight
13%11%39%25%8%1
900
16th to endNight
18%10%37%28%5%
960
February1st to 15thNight
19%10%37%25%6%
880
16th to endNight
14%10%40%24%8%2
755
March1st to 15thNight
17%7%35%28%10%
540
16th to endNight
21%9%34%25%8%
576
April1st to 15thNight
21%9%35%27%6%
539
16th to endNight
24%8%34%21%9%1
540
May1st to 15thNight
16%7%35%29%10%
540
16th to endNight
17%5%30%32%14%
563
June1st to 15thNight
10%428%42%13%
540
16th to endNight
7%428%46%13%
540
July1st to 15thNight
4127%38%25%1
510
16th to endNight
3120%46%25%2
564
August1st to 15thNight
6%119%42%27%2
539
16th to endNight
11%220%38%23%4
573
September1st to 15thNight
11%124%36%22%2
540
16th to endNight
10%7%34%29%16%1
519
October1st to 15thNight
15%9%34%28%11%
660
16th to endNight
21%7%30%29%9%
704
November1st to 15thNight
14%12%34%26%10%
853
16th to endNight
14%13%39%24%7%
900
December1st to 15thNight
19%10%38%26%4
900
16th to endNight
23%8%36%22%7%
960
Page generated at 2017-09-24 08:15:44. Version ac04

Copyright 2017 A. Danko


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