Sioux Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sioux Falls clear sky chart from 2005-11-06 to 2024-03-18.

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%
25041
18%
80631
10%
24946
45%
24946
25%
51404

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 10thNight
30%
941
11%
4504
7%
926
39%
926
11%
3375
January11th to 20thNight
29%
948
16%
4180
7%
930
34%
930
13%
2774
January21st to endNight
24%
1031
11%
4494
4%
1023
33%
1023
11%
3247
February1st to 10thNight
28%
950
14%
2470
4%
950
34%
950
23%
1752
February11th to 20thNight
29%
928
16%
2404
6%
924
35%
924
25%
1651
February21st to endNight
32%
631
19%
1887
6%
631
43%
631
25%
1234
March1st to 10thNight
29%
649
18%
2169
10%
649
38%
649
25%
1350
March11th to 20thNight
31%
564
19%
2068
13%
564
42%
564
20%
1314
March21st to endNight
30%
594
12%
2178
9%
594
36%
594
16%
1481
April1st to 10thNight
29%
540
14%
1919
9%
540
38%
540
21%
1236
April11th to 20thNight
29%
533
20%
1599
12%
533
42%
533
22%
1049
April21st to endNight
31%
540
19%
1620
12%
540
43%
540
24%
1058
May1st to 10thNight
35%
540
16%
1620
11%
540
41%
540
26%
1036
May11th to 20thNight
37%
531
17%
1594
9%
531
44%
531
28%
997
May21st to endNight
40%
583
14%
1553
5%
582
44%
582
28%
1040
June1st to 10thNight
52%
540
20%
1347
7%
540
55%
540
41%
818
June11th to 20thNight
47%
540
20%
1260
7%
540
50%
540
43%
778
June21st to endNight
58%
540
20%
1260
7%
540
61%
540
48%
755
July1st to 10thNight
65%
525
20%
1225
8%
525
67%
525
52%
722
July11th to 20thNight
62%
522
24%
1416
11%
522
66%
522
54%
726
July21st to endNight
65%
591
22%
1673
15%
558
68%
558
48%
856
August1st to 10thNight
61%
537
19%
1601
17%
534
65%
534
34%
945
August11th to 20thNight
61%
534
26%
1600
25%
534
68%
534
41%
872
August21st to endNight
60%
594
28%
1782
27%
594
67%
594
48%
913
September1st to 10thNight
55%
540
23%
1856
22%
540
62%
540
37%
975
September11th to 20thNight
49%
540
27%
1980
22%
540
61%
540
34%
1010
September21st to endNight
42%
540
28%
1980
18%
540
57%
540
34%
1012
October1st to 10thNight
37%
648
25%
2088
15%
648
46%
648
30%
1207
October11th to 20thNight
32%
720
24%
2160
10%
720
42%
720
30%
1273
October21st to endNight
33%
864
24%
2448
11%
864
42%
864
29%
1534
November1st to 10thNight
37%
925
25%
2405
11%
925
46%
925
35%
1487
November11th to 20thNight
32%
950
23%
2612
9%
950
42%
950
28%
1679
November21st to endNight
33%
950
21%
2660
11%
950
41%
950
30%
1666
December1st to 10thNight
30%
950
13%
2660
5%
950
37%
950
23%
1810
December11th to 20thNight
28%
949
14%
3200
7%
949
35%
949
19%
2048
December21st to endNight
22%
1039
9%
5159
6%
1026
31%
1026
9%
3724

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
12%7%36%6%35%5%5%7%41%
78668
Night
10%7%37%5%345%5%7%43%
81159
TransparencyDay
42%6%14%24%12%1
78374
Night
40%6%14%24%14%2
80973
SeeingDay
15%10%32%29%12%2
14953
Night
13%9%35%33%10%1
25075

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 10thDay
11%13%412%12%6%7%5%45%21%
2414
11th to 20thDay
6%13%6%10%7%410%5%8%10%22%
2669
21st to endDay
7%12%7%13%10%6%7%7%46%22%
3135
February1st to 10thDay
9%11%5%11%9%6%6%6%5%7%27%
1710
11th to 20thDay
8%10%5%8%8%46%5%6%5%34%
1678
21st to endDay
11%10%48%5%46%45%7%37%
1570
March1st to 10thDay
14%10%48%5%23438%38%
2010
11th to 20thDay
13%9%48%6%345%5%7%36%
2057
21st to endDay
19%11%48%6%345%5%7%29%
2178
April1st to 10thDay
16%7%36%5%35%5%5%8%37%
2038
11th to 20thDay
19%8%35%5%34446%37%
2312
21st to endDay
22%7%35%42345%7%38%
2340
May1st to 10thDay
18%7%36%5%445%5%7%36%
2340
11th to 20thDay
17%7%35%6%45%46%7%37%
2302
21st to endDay
18%7%35%5%345%5%8%37%
2721
June1st to 10thDay
12%5%2443446%9%48%
2608
11th to 20thDay
13%5%345%345%5%7%45%
2700
21st to endDay
8%425%435%47%9%49%
2700
July1st to 10thDay
6%3244346%6%10%53%
2700
11th to 20thDay
6%21342445%8%59%
2492
21st to endDay
6%3234345%6%9%55%
2546
August1st to 10thDay
9%435%436%6%6%10%43%
2328
11th to 20thDay
10%425%4345%7%9%47%
2301
21st to endDay
7%324435%35%7%57%
2574
September1st to 10thDay
15%5%24423446%51%
2100
11th to 20thDay
11%424423447%55%
1980
21st to endDay
11%4245%2446%7%52%
1980
October1st to 10thDay
17%7%2442445%6%46%
1853
11th to 20thDay
14%7%24324345%53%
1800
21st to endDay
16%8%36%422346%46%
1907
November1st to 10thDay
10%7%345%3346%8%46%
1673
11th to 20thDay
9%8%310%8%45%445%40%
1566
21st to endDay
11%9%36%5%35%5%5%7%41%
1520
December1st to 10thDay
7%9%310%7%46%46%8%35%
1520
11th to 20thDay
8%12%410%8%5%7%5%5%7%30%
1904
21st to endDay
17%7%5%14%8%335%5%7%25%
2442
January1st to 10thNight
10%11%411%13%46%5%5%6%25%
4536
11th to 20thNight
5%9%49%9%48%7%9%8%28%
4296
21st to endNight
6%11%7%12%6%5%7%6%5%7%28%
4532
February1st to 10thNight
9%11%39%7%445%5%6%37%
2470
11th to 20thNight
8%9%48%6%35%45%7%41%
2403
21st to endNight
8%8%37%6%446%6%7%42%
1887
March1st to 10thNight
10%8%46%5%3445%7%44%
2169
11th to 20thNight
11%8%47%5%3445%7%41%
2068
21st to endNight
16%10%36%5%35%45%7%36%
2178
April1st to 10thNight
15%7%35%5%345%5%7%40%
1919
11th to 20thNight
18%8%36%434346%43%
1599
21st to endNight
16%7%45%5%25%46%6%41%
1620
May1st to 10thNight
14%6%2443447%8%44%
1620
11th to 20thNight
14%7%3333445%8%46%
1593
21st to endNight
15%6%25%5%345%7%9%40%
1552
June1st to 10thNight
8%425%32446%7%55%
1347
11th to 20thNight
7%42443447%9%53%
1260
21st to endNight
6%3134235%5%8%59%
1260
July1st to 10thNight
5%3142245%5%9%60%
1260
11th to 20thNight
411332345%8%66%
1463
21st to endNight
43133245%7%9%60%
1772
August1st to 10thNight
7%324437%6%6%8%50%
1611
11th to 20thNight
7%423324448%59%
1600
21st to endNight
6%22422336%7%63%
1782
September1st to 10thNight
9%31442345%7%58%
1856
11th to 20thNight
9%5%2332345%7%58%
1980
21st to endNight
10%423323447%58%
1980
October1st to 10thNight
16%5%13423446%52%
2088
11th to 20thNight
12%6%24423446%52%
2160
21st to endNight
14%7%25%423346%50%
2448
November1st to 10thNight
9%5%245%2445%6%52%
2405
11th to 20thNight
9%6%27%5%245%6%8%45%
2612
21st to endNight
9%7%36%5%3345%8%47%
2660
December1st to 10thNight
8%9%48%6%35%5%6%8%39%
2660
11th to 20thNight
10%9%46%6%35%5%5%8%39%
3288
21st to endNight
17%10%5%13%7%34446%28%
5225

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 10thDay
65%5%11%13%5%
2415
11th to 20thDay
56%5%9%23%7%
2669
21st to endDay
60%8%14%13%6%
3135
February1st to 10thDay
56%7%12%16%9%1
1710
11th to 20thDay
50%6%13%21%9%2
1687
21st to endDay
47%7%14%19%11%1
1570
March1st to 10thDay
46%6%15%24%7%1
2010
11th to 20thDay
48%7%12%23%9%
2057
21st to endDay
55%7%14%18%41
2178
April1st to 10thDay
45%7%14%23%11%1
2038
11th to 20thDay
49%5%10%22%12%2
2312
21st to endDay
47%5%12%25%10%
2340
May1st to 10thDay
48%7%13%20%12%1
2340
11th to 20thDay
46%7%15%22%10%
2306
21st to endDay
46%8%13%22%12%1
2721
June1st to 10thDay
33%8%17%27%13%2
2608
11th to 20thDay
38%7%14%24%14%3
2700
21st to endDay
30%8%16%29%14%2
2700
July1st to 10thDay
26%9%18%31%14%1
2626
11th to 20thDay
24%6%14%29%22%6%
2416
21st to endDay
24%7%18%30%18%2
2405
August1st to 10thDay
35%9%17%25%11%2
2314
11th to 20thDay
33%7%16%31%11%1
2301
21st to endDay
27%6%13%31%19%4
2574
September1st to 10thDay
34%6%11%28%19%2
2100
11th to 20thDay
32%6%17%31%15%1
1980
21st to endDay
31%7%11%31%19%1
1980
October1st to 10thDay
38%6%13%27%15%1
1853
11th to 20thDay
35%413%28%18%3
1800
21st to endDay
42%314%24%15%1
1907
November1st to 10thDay
36%5%16%26%14%3
1673
11th to 20thDay
46%6%14%22%12%
1566
21st to endDay
43%6%15%24%12%1
1520
December1st to 10thDay
47%5%18%19%9%2
1520
11th to 20thDay
54%5%18%18%5%
1901
21st to endDay
58%5%14%16%7%1
2442
January1st to 10thNight
59%6%10%18%7%
4536
11th to 20thNight
49%6%15%20%9%1
4296
21st to endNight
53%9%14%14%9%1
4532
February1st to 10thNight
47%5%12%23%11%1
2470
11th to 20thNight
43%6%12%23%13%3
2404
21st to endNight
41%7%14%22%14%3
1887
March1st to 10thNight
40%5%19%25%9%2
2169
11th to 20thNight
44%6%10%26%13%1
2068
21st to endNight
49%7%15%21%7%1
2178
April1st to 10thNight
42%7%14%23%12%1
1919
11th to 20thNight
43%5%11%23%16%2
1599
21st to endNight
42%6%12%25%13%2
1620
May1st to 10thNight
37%8%14%25%14%1
1620
11th to 20thNight
37%7%15%24%16%2
1594
21st to endNight
39%9%15%21%14%2
1553
June1st to 10thNight
28%7%17%27%19%2
1347
11th to 20thNight
27%7%17%25%19%4
1260
21st to endNight
23%7%17%29%22%2
1260
July1st to 10thNight
21%7%16%33%21%2
1225
11th to 20thNight
16%7%16%32%23%6%
1416
21st to endNight
19%8%15%33%21%4
1673
August1st to 10thNight
30%9%16%28%15%3
1601
11th to 20thNight
24%8%13%36%17%2
1600
21st to endNight
21%6%16%28%24%5%
1782
September1st to 10thNight
26%6%14%28%23%3
1856
11th to 20thNight
27%6%14%34%17%2
1980
21st to endNight
27%6%12%32%21%2
1980
October1st to 10thNight
34%5%12%28%20%1
2088
11th to 20thNight
35%411%28%19%3
2160
21st to endNight
38%5%14%24%18%2
2448
November1st to 10thNight
32%5%15%24%20%4
2405
11th to 20thNight
37%7%15%25%15%1
2612
21st to endNight
38%415%27%15%1
2660
December1st to 10thNight
44%6%17%23%9%
2660
11th to 20thNight
44%6%22%21%6%
3290
21st to endNight
58%6%10%19%7%1
5225

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 10thDay
16%10%37%25%10%2
270
11th to 20thDay
18%13%35%28%6%1
270
21st to endDay
16%11%38%24%10%1
297
February1st to 10thDay
13%18%40%27%3
270
11th to 20thDay
13%17%41%22%7%
270
21st to endDay
16%16%44%21%2
225
March1st to 10thDay
19%16%41%18%5%1
270
11th to 20thDay
22%11%36%21%8%1
261
21st to endDay
27%14%30%21%7%2
264
April1st to 10thDay
23%18%38%18%3
298
11th to 20thDay
26%15%31%23%5%1
590
21st to endDay
25%15%27%21%10%2
600
May1st to 10thDay
22%11%31%26%8%1
603
11th to 20thDay
23%11%29%24%10%3
625
21st to endDay
20%8%29%31%11%2
679
June1st to 10thDay
8%9%25%34%21%3
630
11th to 20thDay
13%8%35%29%11%3
630
21st to endDay
9%6%34%33%16%2
630
July1st to 10thDay
6%322%41%23%5%
621
11th to 20thDay
6%7%31%35%17%3
618
21st to endDay
6%326%41%21%3
684
August1st to 10thDay
10%423%39%21%4
626
11th to 20thDay
11%426%34%22%3
615
21st to endDay
8%6%28%35%19%4
693
September1st to 10thDay
16%9%27%29%17%2
390
11th to 20thDay
10%6%34%34%14%3
270
21st to endDay
13%17%33%27%9%2
270
October1st to 10thDay
21%11%30%25%9%4
270
11th to 20thDay
15%19%34%23%9%
270
21st to endDay
24%17%35%18%6%1
297
November1st to 10thDay
19%11%36%23%7%3
270
11th to 20thDay
14%19%43%17%7%
270
21st to endDay
20%17%33%23%8%
270
December1st to 10thDay
10%13%44%22%10%1
270
11th to 20thDay
15%14%40%27%4
270
21st to endDay
21%14%40%22%3
297
January1st to 10thNight
11%11%39%30%9%1
950
11th to 20thNight
12%12%37%31%6%1
950
21st to endNight
15%10%39%28%7%
1045
February1st to 10thNight
13%12%40%29%6%1
950
11th to 20thNight
12%12%40%30%5%1
929
21st to endNight
13%8%40%30%8%1
631
March1st to 10thNight
14%10%42%28%6%1
649
11th to 20thNight
15%11%38%31%4
564
21st to endNight
18%11%34%27%9%1
594
April1st to 10thNight
19%11%39%27%4
540
11th to 20thNight
22%14%30%26%6%1
533
21st to endNight
19%12%34%25%9%1
540
May1st to 10thNight
18%9%35%30%8%
540
11th to 20thNight
17%9%34%31%9%1
531
21st to endNight
17%6%32%32%12%
584
June1st to 10thNight
9%6%27%39%18%1
540
11th to 20thNight
8%438%39%11%1
540
21st to endNight
8%5%25%49%14%
540
July1st to 10thNight
6%222%45%24%1
525
11th to 20thNight
4128%49%17%
522
21st to endNight
5%225%51%18%
591
August1st to 10thNight
6%224%46%20%1
537
11th to 20thNight
8%324%40%25%1
534
21st to endNight
5%429%42%19%1
594
September1st to 10thNight
9%427%43%14%2
540
11th to 20thNight
10%6%31%35%14%2
540
21st to endNight
12%7%35%34%11%1
540
October1st to 10thNight
17%9%35%28%11%
648
11th to 20thNight
16%13%36%29%7%
720
21st to endNight
18%11%34%28%9%
864
November1st to 10thNight
12%9%37%32%9%1
925
11th to 20thNight
13%12%39%29%7%1
950
21st to endNight
13%11%38%31%7%
950
December1st to 10thNight
13%11%38%31%6%
950
11th to 20thNight
16%8%39%29%7%
950
21st to endNight
21%12%36%26%6%
1045
Page generated at 2024-03-15 13:01:43. Version ac07

Copyright © 2024 Attilla Danko.


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