Albert Lea
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Albert Lea clear sky chart from 2005-11-05 to 2017-09-10.

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
36%
16061
17%
46820
9%
16014
43%
16014
25%
31064

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
25%
900
12%
2506
5%
895
31%
895
18%
1829
January16th to endNight
22%
960
13%
2505
4%
960
28%
960
17%
1912
February1st to 15thNight
24%
879
13%
2288
3%
875
30%
875
20%
1676
February16th to endNight
28%
744
17%
2006
6%
744
37%
744
24%
1366
March1st to 15thNight
31%
567
17%
2007
10%
567
40%
567
22%
1249
March16th to endNight
30%
576
12%
2106
9%
576
37%
576
16%
1458
April1st to 15thNight
29%
539
16%
1797
11%
539
39%
539
20%
1184
April16th to endNight
29%
540
17%
1689
11%
540
39%
540
19%
1184
May1st to 15thNight
35%
540
16%
1528
10%
540
41%
540
26%
1019
May16th to endNight
39%
563
15%
1497
5%
561
45%
561
29%
1003
June1st to 15thNight
49%
540
14%
1440
5%
540
52%
540
32%
949
June16th to endNight
57%
540
18%
1440
8%
540
60%
540
43%
842
July1st to 15thNight
61%
510
15%
1360
7%
510
64%
510
47%
760
July16th to endNight
70%
564
24%
1476
16%
531
72%
531
46%
811
August1st to 15thNight
64%
539
23%
1610
22%
536
68%
536
38%
912
August16th to endNight
58%
573
21%
1803
21%
573
63%
573
36%
1020
September1st to 15thNight
59%
525
24%
1750
24%
525
66%
525
37%
929
September16th to endNight
44%
530
22%
1819
15%
530
55%
530
31%
1020
October1st to 15thNight
37%
660
24%
1980
15%
660
46%
660
31%
1196
October16th to endNight
33%
704
18%
2112
9%
704
41%
704
22%
1393
November1st to 15thNight
31%
808
22%
2373
10%
808
41%
808
26%
1511
November16th to endNight
24%
900
15%
2520
7%
900
32%
900
20%
1776
December1st to 15thNight
22%
900
9%
2520
3%
900
28%
900
15%
1931
December16th to endNight
20%
960
13%
2688
4%
960
27%
960
13%
2134

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%8%36%5%35%45%7%36%
47817
Night
12%7%36%5%3445%6%41%
46995
Cloud CoverDay
25%7%25%424446%31%
47828
Night
24%7%25%423345%36%
46999
Cloud CoverDay
13%8%36%5%3445%7%36%
47826
Night
12%7%36%5%3445%7%41%
46999
TransparencyDay
46%7%14%21%9%
47509
Night
42%5%13%23%12%1
46821
SeeingDay
16%7%29%27%14%3
6063
Night
16%8%32%29%11%1
16062

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%12%6%9%8%47%46%6%24%
1432
16th to endDay
10%12%7%10%8%46%5%6%8%20%
1719
February1st to 15thDay
9%13%5%10%8%45%46%6%24%
1575
16th to endDay
13%9%38%6%26%45%7%30%
1467
March1st to 15thDay
14%10%5%8%5%35%446%31%
1953
16th to endDay
19%9%46%5%2445%7%29%
2118
April1st to 15thDay
18%9%36%5%2445%7%31%
2151
16th to endDay
24%11%35%42444428%
2269
May1st to 15thDay
20%9%26%5%3445%7%30%
2421
16th to endDay
17%5%25%435%45%7%37%
2617
June1st to 15thDay
15%5%26%42445%7%40%
2520
16th to endDay
10%424435%5%7%9%43%
2520
July1st to 15thDay
6%314435%46%9%49%
2520
16th to endDay
8%425%4245%6%9%45%
2590
August1st to 15thDay
9%5%25%5%35%6%5%9%41%
2340
16th to endDay
12%5%245%245%48%44%
2398
September1st to 15thDay
12%32442435%8%47%
2097
16th to endDay
12%6%26%43445%7%43%
1799
October1st to 15thDay
15%5%24424346%46%
1650
16th to endDay
16%8%37%413446%38%
1760
November1st to 15thDay
10%8%35%42435%5%44%
1485
16th to endDay
13%10%47%6%23347%35%
1440
December1st to 15thDay
17%10%49%9%5%6%5%5%5%22%
1440
16th to endDay
18%15%7%10%6%36%445%19%
1536
January1st to 15thNight
9%8%48%7%46%6%6%7%29%
2506
16th to endNight
11%10%5%10%7%35%46%6%27%
2505
February1st to 15thNight
10%12%6%8%6%3435%6%32%
2285
16th to endNight
9%7%46%6%345%6%7%37%
2006
March1st to 15thNight
14%9%35%422346%43%
1995
16th to endNight
16%9%46%5%3445%6%33%
2106
April1st to 15thNight
16%9%345%24445%39%
1797
16th to endNight
23%8%35%424435%36%
1689
May1st to 15thNight
17%6%2432335%6%43%
1528
16th to endNight
13%6%25%5%245%5%8%41%
1496
June1st to 15thNight
11%414435%46%9%44%
1440
16th to endNight
8%21432345%8%55%
1440
July1st to 15thNight
331342245%9%58%
1440
16th to endNight
421332335%9%59%
1577
August1st to 15thNight
6%315%42446%8%52%
1620
16th to endNight
9%424323335%58%
1803
September1st to 15thNight
9%314322347%56%
1750
16th to endNight
10%433313346%53%
1819
October1st to 15thNight
14%413423335%50%
1980
16th to endNight
16%8%25%423346%41%
2112
November1st to 15thNight
12%7%35%42434445%
2373
16th to endNight
13%9%36%5%24446%37%
2520
December1st to 15thNight
13%10%48%8%45%446%28%
2520
16th to endNight
18%13%6%9%7%34445%22%
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
23%9%37%8%46%45%5%21%
1432
16th to endDay
24%10%5%9%7%36%45%6%17%
1719
February1st to 15thDay
24%10%48%7%34345%22%
1575
16th to endDay
26%8%37%5%15%345%26%
1467
March1st to 15thDay
26%9%38%42443427%
1964
16th to endDay
30%8%35%423445%26%
2118
April1st to 15thDay
31%8%25%423346%26%
2151
16th to endDay
37%10%2442234422%
2269
May1st to 15thDay
33%7%25%423335%26%
2421
16th to endDay
32%5%24424345%31%
2617
June1st to 15thDay
30%5%25%423345%32%
2520
16th to endDay
25%42332345%7%36%
2520
July1st to 15thDay
15%9%1443445%7%39%
2520
16th to endDay
23%3143235%5%8%37%
2590
August1st to 15thDay
16%425%435%5%5%8%38%
2340
16th to endDay
19%5%23423447%42%
2398
September1st to 15thDay
18%314423347%45%
2097
16th to endDay
19%5%25%433445%40%
1799
October1st to 15thDay
24%414323335%42%
1650
16th to endDay
23%8%26%413435%36%
1760
November1st to 15thDay
23%6%2431435%439%
1485
16th to endDay
28%7%26%422335%32%
1440
December1st to 15thDay
31%9%38%8%335%3418%
1440
16th to endDay
30%13%5%8%5%2433417%
1536
January1st to 15thNight
23%7%27%6%45%5%46%26%
2506
16th to endNight
26%9%38%5%3435%5%22%
2505
February1st to 15thNight
23%10%48%5%2323429%
2278
16th to endNight
23%6%25%5%3345%6%32%
2006
March1st to 15thNight
27%8%23412235%37%
2007
16th to endNight
28%8%35%433445%29%
2106
April1st to 15thNight
30%8%2342333433%
1797
16th to endNight
35%7%2332332429%
1689
May1st to 15thNight
31%5%13312245%37%
1527
16th to endNight
30%414323346%34%
1496
June1st to 15thNight
25%41442445%7%36%
1440
16th to endNight
24%213312347%46%
1440
July1st to 15thNight
13%8%12312347%48%
1440
16th to endNight
19%22322337%50%
1577
August1st to 15thNight
14%4332435%8%48%
1620
16th to endNight
16%41431223454%
1803
September1st to 15thNight
16%313322246%52%
1750
16th to endNight
18%423312336%50%
1819
October1st to 15thNight
22%41342333446%
1980
16th to endNight
23%8%14422345%38%
2112
November1st to 15thNight
24%6%15%42234440%
2373
16th to endNight
26%8%36%42333433%
2520
December1st to 15thNight
27%9%47%7%3343423%
2520
16th to endNight
31%12%38%7%2223420%
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%13%6%8%9%47%46%7%23%
1432
16th to endDay
10%12%7%11%8%45%5%6%8%20%
1719
February1st to 15thDay
8%14%5%10%8%46%46%6%25%
1575
16th to endDay
13%9%39%5%26%45%7%30%
1467
March1st to 15thDay
14%11%48%5%35%5%45%31%
1964
16th to endDay
18%10%46%5%2445%7%29%
2116
April1st to 15thDay
18%9%46%5%2345%7%30%
2151
16th to endDay
24%11%35%424445%28%
2269
May1st to 15thDay
19%9%36%43445%7%30%
2421
16th to endDay
16%6%25%435%45%6%37%
2617
June1st to 15thDay
14%6%26%5%2445%7%40%
2520
16th to endDay
10%5%244345%6%9%43%
2520
July1st to 15thDay
5%3145%35%46%10%48%
2520
16th to endDay
6%425%435%5%6%9%45%
2590
August1st to 15thDay
8%5%25%5%35%6%6%9%40%
2340
16th to endDay
12%5%2443445%8%43%
2398
September1st to 15thDay
11%42442346%8%47%
2097
16th to endDay
11%6%26%5%3445%7%42%
1799
October1st to 15thDay
15%6%34334446%45%
1650
16th to endDay
16%8%36%41345%5%38%
1760
November1st to 15thDay
10%8%35%42445%6%43%
1485
16th to endDay
14%10%46%5%24348%35%
1440
December1st to 15thDay
16%10%49%9%45%6%5%5%21%
1440
16th to endDay
18%14%6%10%6%35%445%19%
1536
January1st to 15thNight
9%8%48%7%47%5%6%7%29%
2506
16th to endNight
11%10%5%10%7%35%5%5%7%27%
2505
February1st to 15thNight
9%12%5%8%6%3436%5%32%
2278
16th to endNight
9%7%36%7%345%7%7%37%
2006
March1st to 15thNight
14%9%34432347%43%
2007
16th to endNight
16%8%46%6%3445%6%33%
2106
April1st to 15thNight
15%10%24424445%39%
1797
16th to endNight
22%9%25%43333436%
1689
May1st to 15thNight
17%5%34424247%43%
1527
16th to endNight
13%6%35%5%235%5%8%40%
1496
June1st to 15thNight
10%4244245%6%9%44%
1440
16th to endNight
8%21432445%9%54%
1440
July1st to 15thNight
321341345%9%58%
1440
16th to endNight
321342336%8%59%
1577
August1st to 15thNight
5%3245%2445%10%51%
1620
16th to endNight
8%423323335%57%
1803
September1st to 15thNight
9%314233247%56%
1750
16th to endNight
10%5%2432335%6%52%
1819
October1st to 15thNight
13%5%24423345%50%
1980
16th to endNight
15%7%35%5%23446%41%
2112
November1st to 15thNight
12%7%26%424345%45%
2373
16th to endNight
13%10%46%5%24446%37%
2520
December1st to 15thNight
13%10%48%8%45%5%46%27%
2520
16th to endNight
18%13%6%9%7%34445%22%
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
58%6%11%15%8%
1433
16th to endDay
61%6%14%13%4
1719
February1st to 15thDay
58%5%12%16%6%
1576
16th to endDay
51%5%12%20%7%1
1467
March1st to 15thDay
52%7%13%19%6%
1964
16th to endDay
54%7%13%19%5%
2118
April1st to 15thDay
51%5%13%19%8%
2151
16th to endDay
57%5%13%15%6%1
2269
May1st to 15thDay
52%7%15%18%6%
2421
16th to endDay
45%8%13%19%11%1
2621
June1st to 15thDay
41%7%14%24%11%
2520
16th to endDay
34%8%17%24%12%1
2520
July1st to 15thDay
32%7%17%28%12%1
2371
16th to endDay
33%8%17%25%14%1
2428
August1st to 15thDay
37%9%14%26%10%1
2326
16th to endDay
37%7%14%25%12%1
2398
September1st to 15thDay
34%7%13%30%13%
2097
16th to endDay
40%7%13%27%10%
1799
October1st to 15thDay
40%413%24%15%1
1650
16th to endDay
46%6%13%23%9%
1760
November1st to 15thDay
39%6%12%23%15%1
1485
16th to endDay
49%5%18%18%8%
1440
December1st to 15thDay
62%7%13%10%5%1
1440
16th to endDay
67%5%9%12%4
1536
January1st to 15thNight
51%6%14%17%9%
2506
16th to endNight
54%6%14%16%7%
2505
February1st to 15thNight
51%5%13%21%8%
2288
16th to endNight
43%6%14%23%11%1
2006
March1st to 15thNight
41%5%14%27%9%1
2007
16th to endNight
50%6%14%21%6%
2106
April1st to 15thNight
45%5%10%23%13%1
1797
16th to endNight
50%5%11%18%12%2
1689
May1st to 15thNight
41%6%13%24%12%1
1528
16th to endNight
38%7%14%23%14%1
1498
June1st to 15thNight
35%8%13%28%12%1
1440
16th to endNight
25%7%15%28%19%2
1440
July1st to 15thNight
22%7%17%31%17%3
1360
16th to endNight
22%6%15%32%19%3
1476
August1st to 15thNight
27%6%14%29%18%2
1610
16th to endNight
29%6%14%28%18%3
1803
September1st to 15thNight
27%412%29%23%1
1750
16th to endNight
32%5%13%29%18%1
1819
October1st to 15thNight
35%5%12%28%16%2
1980
16th to endNight
44%5%13%22%13%
2112
November1st to 15thNight
40%412%22%17%2
2373
16th to endNight
47%5%14%22%8%1
2520
December1st to 15thNight
56%6%13%17%5%
2520
16th to endNight
63%411%13%6%
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
25%11%30%26%42
90
16th to endDay
16%7%44%25%5%1
96
February1st to 15thDay
12%16%41%27%2
90
16th to endDay
30%6%24%29%7%1
81
March1st to 15thDay
22%13%34%25%4
90
16th to endDay
35%6%33%18%5%
102
April1st to 15thDay
25%9%32%23%8%
270
16th to endDay
33%12%24%17%8%2
379
May1st to 15thDay
20%12%35%21%7%2
468
16th to endDay
22%8%29%22%14%2
517
June1st to 15thDay
15%5%28%30%15%4
495
16th to endDay
9%6%34%30%16%3
495
July1st to 15thDay
6%326%34%20%7%
475
16th to endDay
9%225%33%22%5%
515
August1st to 15thDay
8%224%35%25%4
493
16th to endDay
14%5%21%31%19%8%
438
September1st to 15thDay
11%428%28%21%6%
294
16th to endDay
12%9%33%25%13%6%
123
October1st to 15thDay
8%11%33%27%14%4
90
16th to endDay
25%11%35%18%9%
96
November1st to 15thDay
48%32%42%7%4
90
16th to endDay
33%14%26%23%2
90
December1st to 15thDay
24%12%33%24%5%
90
16th to endDay
33%23%22%18%1
96
January1st to 15thNight
14%12%39%24%7%1
900
16th to endNight
17%12%38%26%5%
960
February1st to 15thNight
16%10%38%25%7%1
880
16th to endNight
13%13%37%24%9%1
744
March1st to 15thNight
17%10%34%26%9%
567
16th to endNight
18%9%35%26%7%1
576
April1st to 15thNight
20%10%35%27%5%
539
16th to endNight
26%9%31%24%7%1
540
May1st to 15thNight
19%9%33%29%7%
540
16th to endNight
16%5%32%33%11%
563
June1st to 15thNight
12%427%41%13%
540
16th to endNight
8%227%46%13%
540
July1st to 15thNight
3127%35%29%1
510
16th to endNight
5%117%48%25%2
564
August1st to 15thNight
6%120%42%25%2
539
16th to endNight
11%122%38%22%3
573
September1st to 15thNight
12%322%37%20%4
525
16th to endNight
11%8%32%29%17%1
530
October1st to 15thNight
16%8%34%25%14%1
660
16th to endNight
20%9%29%29%9%
704
November1st to 15thNight
16%11%37%26%7%1
808
16th to endNight
18%14%37%20%8%
900
December1st to 15thNight
19%10%38%25%5%
900
16th to endNight
25%9%33%24%5%
960
Page generated at 2017-09-11 18:35:22. Version ac04

Copyright 2017 A. Danko


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