Mason City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mason City clear sky chart from 2005-11-05 to 2017-10-31.

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%
16226
18%
47405
10%
16179
44%
16179
26%
30942

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
13%
2506
5%
895
34%
895
20%
1778
January16th to endNight
22%
960
15%
2496
5%
960
29%
960
19%
1836
February1st to 15thNight
24%
879
13%
2288
4%
875
31%
875
21%
1667
February16th to endNight
30%
735
19%
1997
6%
735
39%
735
25%
1336
March1st to 15thNight
33%
568
19%
2008
12%
568
43%
568
23%
1215
March16th to endNight
28%
576
13%
2103
9%
576
36%
576
15%
1454
April1st to 15thNight
30%
539
17%
1797
12%
539
40%
539
22%
1170
April16th to endNight
30%
540
18%
1704
10%
540
42%
540
22%
1155
May1st to 15thNight
36%
540
17%
1533
11%
540
42%
540
25%
1037
May16th to endNight
42%
563
16%
1497
6%
561
48%
561
30%
993
June1st to 15thNight
52%
540
14%
1440
6%
540
54%
540
31%
942
June16th to endNight
58%
540
18%
1440
8%
540
61%
540
43%
836
July1st to 15thNight
64%
510
16%
1360
7%
510
67%
510
46%
765
July16th to endNight
72%
564
24%
1484
17%
531
74%
531
47%
797
August1st to 15thNight
66%
539
23%
1610
21%
536
70%
536
38%
906
August16th to endNight
60%
573
22%
1815
22%
573
65%
573
36%
1010
September1st to 15thNight
60%
540
26%
1800
25%
540
66%
540
37%
957
September16th to endNight
45%
582
24%
1983
18%
582
56%
582
32%
1115
October1st to 15thNight
36%
720
23%
2160
13%
720
44%
720
31%
1308
October16th to endNight
32%
768
21%
2304
10%
768
42%
768
25%
1476
November1st to 15thNight
33%
790
24%
2352
12%
790
44%
790
28%
1452
November16th to endNight
26%
900
15%
2520
7%
900
33%
900
22%
1745
December1st to 15thNight
22%
900
10%
2520
3%
900
29%
900
17%
1890
December16th to endNight
21%
960
13%
2688
4%
960
29%
960
14%
2102

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
14%7%35%5%3445%7%37%
48348
Night
13%7%35%5%24446%42%
47581
Cloud CoverDay
12%20%25%423346%32%
48359
Night
10%20%25%423345%37%
47585
Cloud CoverDay
14%7%36%5%35%45%7%36%
48357
Night
12%7%35%5%24447%42%
47585
TransparencyDay
45%6%14%22%10%
48041
Night
41%5%13%24%13%1
47406
SeeingDay
16%7%28%28%15%3
6207
Night
16%7%31%30%11%1
16227

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
9%11%6%8%8%46%5%47%28%
1432
16th to endDay
12%10%6%10%6%46%5%6%7%22%
1725
February1st to 15thDay
11%12%5%9%7%4445%6%28%
1575
16th to endDay
15%9%36%5%25%45%7%33%
1476
March1st to 15thDay
14%9%47%4245%48%33%
1951
16th to endDay
20%10%47%5%2445%6%29%
2121
April1st to 15thDay
18%8%46%5%24446%32%
2151
16th to endDay
24%10%35%5%33345%29%
2253
May1st to 15thDay
22%7%35%435%45%7%30%
2416
16th to endDay
16%6%35%425%5%5%6%37%
2617
June1st to 15thDay
15%6%243245%5%8%40%
2520
16th to endDay
9%425%435%5%7%10%42%
2520
July1st to 15thDay
7%4244345%7%9%47%
2520
16th to endDay
7%3245%25%5%7%8%46%
2581
August1st to 15thDay
9%5%25%426%5%6%8%42%
2340
16th to endDay
12%425%43446%7%43%
2387
September1st to 15thDay
10%415%42335%7%49%
2160
16th to endDay
12%6%2443335%7%45%
1965
October1st to 15thDay
18%5%25%424345%43%
1800
16th to endDay
17%9%24424346%41%
1919
November1st to 15thDay
11%6%44423447%45%
1503
16th to endDay
15%9%35%5%3335%6%37%
1440
December1st to 15thDay
18%9%5%6%7%36%5%47%24%
1440
16th to endDay
18%14%6%8%6%35%436%21%
1536
January1st to 15thNight
10%8%37%6%35%6%5%8%32%
2506
16th to endNight
11%11%48%6%34447%31%
2496
February1st to 15thNight
11%11%48%6%2445%6%33%
2285
16th to endNight
10%7%35%6%25%45%6%41%
1997
March1st to 15thNight
14%8%24423436%45%
1996
16th to endNight
16%9%46%5%44446%33%
2103
April1st to 15thNight
17%7%345%24345%40%
1797
16th to endNight
23%6%25%22334440%
1704
May1st to 15thNight
18%5%24324446%42%
1533
16th to endNight
13%5%245%24447%43%
1496
June1st to 15thNight
12%3135%25%7%6%7%43%
1440
16th to endNight
9%31332335%11%53%
1440
July1st to 15thNight
431342335%8%58%
1440
16th to endNight
5%2232446%9%59%
1586
August1st to 15thNight
6%3144345%6%8%52%
1620
16th to endNight
9%42331235%7%54%
1815
September1st to 15thNight
9%324313345%58%
1800
16th to endNight
12%424323347%51%
1983
October1st to 15thNight
14%424423446%48%
2160
16th to endNight
14%7%345%24336%44%
2304
November1st to 15thNight
11%6%35%5%23445%47%
2352
16th to endNight
15%9%35%42335%6%39%
2520
December1st to 15thNight
15%10%49%7%34446%29%
2520
16th to endNight
19%11%5%8%7%34345%25%
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
6%25%46%8%36%436%24%
1432
16th to endDay
10%25%5%8%6%45%45%6%18%
1725
February1st to 15thDay
9%26%48%6%33245%25%
1575
16th to endDay
11%25%25%424345%29%
1476
March1st to 15thDay
11%25%26%314347%29%
1962
16th to endDay
14%25%26%414345%26%
2121
April1st to 15thDay
14%24%36%423435%27%
2151
16th to endDay
21%26%2442234423%
2253
May1st to 15thDay
17%23%25%434346%26%
2416
16th to endDay
14%23%1442444431%
2617
June1st to 15thDay
14%21%24323447%32%
2520
16th to endDay
8%21%1432345%8%35%
2520
July1st to 15thDay
13%13%1432346%8%37%
2520
16th to endDay
7%19%1342346%6%38%
2581
August1st to 15thDay
7%13%24435%45%7%40%
2340
16th to endDay
10%13%1442345%6%41%
2387
September1st to 15thDay
8%12%1442335%6%46%
2160
16th to endDay
10%13%24433346%42%
1965
October1st to 15thDay
17%13%24324335%41%
1800
16th to endDay
15%16%14423245%38%
1919
November1st to 15thDay
8%20%24323346%40%
1503
16th to endDay
12%24%23422235%34%
1440
December1st to 15thDay
16%25%46%5%33445%20%
1440
16th to endDay
14%29%48%5%3332419%
1536
January1st to 15thNight
6%24%27%6%34447%28%
2506
16th to endNight
9%25%38%5%33336%26%
2496
February1st to 15thNight
8%26%37%5%1334429%
2278
16th to endNight
8%22%25%5%23445%35%
1997
March1st to 15thNight
11%23%24322335%38%
2008
16th to endNight
11%25%25%5%33335%29%
2103
April1st to 15thNight
14%23%1342334434%
1797
16th to endNight
19%23%1422224331%
1704
May1st to 15thNight
15%21%13323335%36%
1532
16th to endNight
11%22%14423346%35%
1496
June1st to 15thNight
11%19%134236%5%6%35%
1440
16th to endNight
7%19%3212248%45%
1440
July1st to 15thNight
9%13%13322348%47%
1440
16th to endNight
418%2223347%49%
1586
August1st to 15thNight
5%11%1333346%7%49%
1620
16th to endNight
8%12%13312246%52%
1815
September1st to 15thNight
7%12%14323245%54%
1800
16th to endNight
11%12%13312246%49%
1983
October1st to 15thNight
13%13%14323335%44%
2160
16th to endNight
12%14%24414335%41%
2304
November1st to 15thNight
9%19%15%422335%42%
2352
16th to endNight
11%25%25%422245%34%
2520
December1st to 15thNight
13%25%38%6%23335%23%
2520
16th to endNight
16%26%47%6%3233422%
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
9%10%6%8%8%5%6%447%28%
1432
16th to endDay
11%11%6%10%7%46%5%5%7%21%
1725
February1st to 15thDay
10%13%49%7%35%447%27%
1575
16th to endDay
15%9%37%5%26%45%8%32%
1476
March1st to 15thDay
14%9%47%4245%5%8%33%
1962
16th to endDay
19%10%36%5%2445%6%29%
2119
April1st to 15thDay
18%9%47%5%24446%32%
2151
16th to endDay
24%10%35%5%23345%29%
2253
May1st to 15thDay
21%7%35%5%3445%7%30%
2416
16th to endDay
16%6%35%5%25%5%5%6%37%
2617
June1st to 15thDay
14%6%25%4245%5%8%39%
2520
16th to endDay
9%425%5%345%7%10%41%
2520
July1st to 15thDay
6%425%4345%6%9%47%
2520
16th to endDay
6%425%435%5%6%10%45%
2581
August1st to 15thDay
7%6%35%5%36%5%6%8%41%
2340
16th to endDay
11%5%25%435%5%6%7%42%
2387
September1st to 15thDay
10%415%5%2335%7%48%
2160
16th to endDay
12%5%25%43445%7%44%
1965
October1st to 15thDay
18%5%34414435%43%
1800
16th to endDay
16%9%25%424346%41%
1919
November1st to 15thDay
11%7%345%2345%6%45%
1503
16th to endDay
14%10%26%5%24347%37%
1440
December1st to 15thDay
18%10%47%7%25%6%5%7%23%
1440
16th to endDay
17%15%7%8%6%35%436%21%
1536
January1st to 15thNight
9%8%47%7%35%6%5%8%32%
2506
16th to endNight
11%10%49%6%34447%31%
2496
February1st to 15thNight
10%11%48%6%2445%6%34%
2278
16th to endNight
10%8%36%6%25%446%41%
1997
March1st to 15thNight
14%7%35%323436%45%
2008
16th to endNight
16%9%46%5%44446%33%
2103
April1st to 15thNight
16%8%345%24445%40%
1797
16th to endNight
23%7%25%323345%39%
1704
May1st to 15thNight
18%6%245%23446%42%
1532
16th to endNight
12%6%345%3445%7%43%
1496
June1st to 15thNight
11%4135%247%6%8%43%
1440
16th to endNight
8%31331345%11%53%
1440
July1st to 15thNight
4313424449%58%
1440
16th to endNight
431332345%9%59%
1586
August1st to 15thNight
5%4144235%6%10%50%
1620
16th to endNight
9%41432335%6%55%
1815
September1st to 15thNight
9%42432244458%
1800
16th to endNight
11%5%23323347%52%
1983
October1st to 15thNight
13%5%235%23446%48%
2160
16th to endNight
14%7%35%5%23445%43%
2304
November1st to 15thNight
11%6%35%5%14345%47%
2352
16th to endNight
14%10%36%5%23346%39%
2520
December1st to 15thNight
15%10%49%7%34446%29%
2520
16th to endNight
19%12%5%8%7%34446%24%
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%412%16%10%
1433
16th to endDay
60%414%14%5%
1725
February1st to 15thDay
55%313%20%6%
1576
16th to endDay
49%6%12%21%8%1
1476
March1st to 15thDay
48%6%16%20%6%
1962
16th to endDay
54%6%13%19%5%
2121
April1st to 15thDay
52%5%12%19%9%
2151
16th to endDay
56%412%17%7%1
2253
May1st to 15thDay
52%5%14%20%6%
2416
16th to endDay
46%6%14%19%11%2
2621
June1st to 15thDay
40%7%14%24%12%
2520
16th to endDay
35%7%15%26%14%
2520
July1st to 15thDay
32%6%16%27%13%2
2371
16th to endDay
31%8%17%25%14%1
2420
August1st to 15thDay
36%8%13%27%12%1
2326
16th to endDay
38%7%12%26%14%1
2387
September1st to 15thDay
33%6%13%31%14%
2160
16th to endDay
38%5%13%30%11%
1965
October1st to 15thDay
42%411%23%16%1
1800
16th to endDay
45%313%25%11%
1919
November1st to 15thDay
37%5%13%26%15%1
1503
16th to endDay
47%5%18%21%7%
1440
December1st to 15thDay
58%5%14%14%6%
1440
16th to endDay
65%410%12%6%
1536
January1st to 15thNight
48%6%14%19%10%
2506
16th to endNight
52%415%19%7%
2496
February1st to 15thNight
50%413%22%9%
2288
16th to endNight
42%5%14%25%11%2
1997
March1st to 15thNight
40%414%27%11%1
2008
16th to endNight
51%5%13%21%6%
2103
April1st to 15thNight
44%411%24%12%1
1797
16th to endNight
47%412%21%12%2
1704
May1st to 15thNight
42%6%11%24%13%
1533
16th to endNight
39%6%13%25%14%1
1498
June1st to 15thNight
35%9%14%25%13%1
1440
16th to endNight
26%6%16%27%20%3
1440
July1st to 15thNight
23%5%17%32%17%3
1360
16th to endNight
20%7%15%33%19%3
1484
August1st to 15thNight
27%7%13%30%18%2
1610
16th to endNight
29%5%14%28%17%4
1815
September1st to 15thNight
28%410%29%25%1
1800
16th to endNight
32%411%30%19%1
1983
October1st to 15thNight
36%312%26%18%2
2160
16th to endNight
41%414%21%16%1
2304
November1st to 15thNight
37%412%24%18%2
2352
16th to endNight
46%5%14%23%8%1
2520
December1st to 15thNight
55%5%14%17%6%
2520
16th to endNight
61%411%14%7%
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
21%7%35%26%7%1
90
16th to endDay
17%7%35%30%7%2
96
February1st to 15thDay
8%20%36%30%4
90
16th to endDay
29%11%24%19%13%1
81
March1st to 15thDay
23%15%36%17%6%
90
16th to endDay
39%9%24%23%1
105
April1st to 15thDay
22%11%30%25%9%
270
16th to endDay
31%12%27%19%7%2
363
May1st to 15thDay
22%12%33%20%8%2
468
16th to endDay
21%9%28%24%13%2
517
June1st to 15thDay
16%5%25%32%17%2
495
16th to endDay
9%6%32%32%16%3
495
July1st to 15thDay
7%224%34%21%9%
475
16th to endDay
9%124%32%26%5%
515
August1st to 15thDay
8%222%35%25%6%
493
16th to endDay
14%421%30%22%7%
427
September1st to 15thDay
9%326%28%23%7%
315
16th to endDay
13%9%31%31%10%3
177
October1st to 15thDay
22%7%33%20%11%3
135
16th to endDay
22%14%31%19%11%
144
November1st to 15thDay
35%36%37%12%4
90
16th to endDay
37%15%25%14%6%
90
December1st to 15thDay
24%12%34%23%5%
90
16th to endDay
33%18%29%16%2
96
January1st to 15thNight
14%12%37%26%7%1
900
16th to endNight
18%10%38%26%6%
960
February1st to 15thNight
16%10%37%26%7%1
880
16th to endNight
15%11%36%27%7%1
735
March1st to 15thNight
19%8%33%27%9%
568
16th to endNight
19%8%37%25%8%1
576
April1st to 15thNight
20%9%34%28%6%
539
16th to endNight
26%6%34%25%6%2
540
May1st to 15thNight
19%7%32%31%8%
540
16th to endNight
15%6%31%33%11%
563
June1st to 15thNight
13%425%42%13%
540
16th to endNight
9%225%47%14%
540
July1st to 15thNight
4123%38%30%2
510
16th to endNight
5%16%49%26%2
564
August1st to 15thNight
7%117%45%25%2
539
16th to endNight
10%219%40%21%5%
573
September1st to 15thNight
10%221%38%22%4
540
16th to endNight
14%6%29%30%17%1
582
October1st to 15thNight
16%6%36%25%13%1
720
16th to endNight
18%10%32%29%9%
768
November1st to 15thNight
14%9%37%28%8%
790
16th to endNight
19%13%37%21%8%
900
December1st to 15thNight
20%11%37%25%5%
900
16th to endNight
25%9%31%26%7%
960
Page generated at 2017-11-01 16:23:32. Version ac04

Copyright 2017 A. Danko


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