Iola
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Iola clear sky chart from 2005-11-05 to 2017-04-26.

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
42%
15412
25%
45792
15%
15366
51%
15366
34%
26568

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
30%
899
26%
2327
9%
895
42%
895
36%
1412
January16th to endNight
31%
960
30%
2496
11%
960
43%
960
38%
1478
February1st to 15thNight
27%
880
20%
2288
7%
876
35%
876
29%
1494
February16th to endNight
27%
636
27%
1898
9%
636
40%
636
30%
1120
March1st to 15thNight
34%
540
23%
1980
13%
540
46%
540
25%
1157
March16th to endNight
26%
576
17%
2112
10%
576
36%
576
21%
1303
April1st to 15thNight
33%
539
23%
1880
14%
539
48%
539
28%
1050
April16th to endNight
32%
528
21%
1660
14%
528
45%
528
27%
1018
May1st to 15thNight
38%
494
22%
1485
17%
494
47%
494
29%
938
May16th to endNight
46%
515
18%
1541
16%
513
52%
513
31%
937
June1st to 15thNight
61%
495
20%
1485
14%
495
66%
495
40%
823
June16th to endNight
62%
495
21%
1485
15%
495
67%
495
50%
741
July1st to 15thNight
67%
465
20%
1395
18%
465
69%
465
42%
762
July16th to endNight
76%
522
24%
1468
25%
489
78%
489
44%
772
August1st to 15thNight
77%
494
26%
1475
31%
491
78%
491
43%
781
August16th to endNight
73%
525
26%
1652
29%
525
75%
525
43%
848
September1st to 15thNight
61%
495
26%
1737
30%
495
64%
495
31%
978
September16th to endNight
63%
492
31%
1815
29%
492
71%
492
37%
898
October1st to 15thNight
47%
632
30%
1952
21%
632
53%
632
34%
1112
October16th to endNight
39%
704
31%
2112
15%
704
52%
704
41%
1113
November1st to 15thNight
41%
766
31%
2166
15%
766
54%
766
40%
1187
November16th to endNight
31%
900
27%
2373
10%
900
43%
900
35%
1426
December1st to 15thNight
30%
900
21%
2514
9%
900
39%
900
30%
1580
December16th to endNight
31%
960
27%
2496
10%
960
43%
960
30%
1640

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%5%2442445%7%45%
45854
Night
10%5%24323347%51%
45987
TransparencyDay
38%312%26%15%2
45554
Night
33%311%27%19%4
45792
SeeingDay
13%6%25%29%20%4
5187
Night
13%8%30%32%13%1
15414

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 15thDay
10%6%245%23335%51%
1611
16th to endDay
12%5%46%424247%46%
1728
February1st to 15thDay
11%9%46%433246%43%
1575
16th to endDay
12%7%35%424345%44%
1582
March1st to 15thDay
14%8%35%5%35%5%45%39%
1980
16th to endDay
22%7%35%423335%37%
2110
April1st to 15thDay
14%7%34424346%44%
2067
16th to endDay
17%7%36%434335%37%
2209
May1st to 15thDay
20%7%35%434446%34%
2136
16th to endDay
16%6%27%436%5%5%8%32%
2222
June1st to 15thDay
9%4245%35%46%9%44%
2145
16th to endDay
6%212435%47%9%52%
2145
July1st to 15thDay
9%414425%5%7%9%44%
2145
16th to endDay
6%314435%5%7%9%47%
2284
August1st to 15thDay
6%3235%35%45%11%49%
2145
16th to endDay
7%42442446%7%50%
2198
September1st to 15thDay
14%5%25%5%23346%46%
1890
16th to endDay
9%41342345%7%53%
1815
October1st to 15thDay
13%5%24323336%51%
1666
16th to endDay
11%424322345%54%
1760
November1st to 15thDay
9%413323346%57%
1692
16th to endDay
15%5%13212235%55%
1581
December1st to 15thDay
15%7%35%5%12347%43%
1440
16th to endDay
15%8%36%42335%6%42%
1728
January1st to 15thNight
10%5%23432346%52%
2327
16th to endNight
8%5%24323346%55%
2496
February1st to 15thNight
10%8%35%423345%46%
2278
16th to endNight
10%6%25%5%23346%49%
1898
March1st to 15thNight
12%6%24425%446%46%
1980
16th to endNight
18%6%25%32435%5%42%
2112
April1st to 15thNight
10%6%24324446%50%
1880
16th to endNight
15%5%35%422446%46%
1660
May1st to 15thNight
14%5%35%4235%5%7%44%
1484
16th to endNight
11%5%25%425%45%10%44%
1539
June1st to 15thNight
6%3223345%5%10%52%
1485
16th to endNight
421232345%9%59%
1485
July1st to 15thNight
6%315%3245%5%10%51%
1485
16th to endNight
5%1133345%6%10%52%
1576
August1st to 15thNight
5%2133346%5%8%56%
1485
16th to endNight
6%313424448%56%
1652
September1st to 15thNight
11%425%424347%50%
1737
16th to endNight
7%32332345%6%56%
1815
October1st to 15thNight
14%324323335%54%
1952
16th to endNight
8%413313346%59%
2112
November1st to 15thNight
10%423212335%59%
2166
16th to endNight
14%5%23213235%54%
2373
December1st to 15thNight
15%6%25%222447%46%
2514
16th to endNight
14%8%35%424246%44%
2496

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
37%211%29%18%1
1612
16th to endDay
38%114%27%15%1
1728
February1st to 15thDay
42%313%27%10%2
1576
16th to endDay
41%212%27%14%2
1582
March1st to 15thDay
46%310%22%14%3
1980
16th to endDay
50%312%22%9%1
2112
April1st to 15thDay
41%314%25%14%1
2067
16th to endDay
47%311%23%12%1
2209
May1st to 15thDay
50%311%21%11%
2136
16th to endDay
48%5%14%21%8%1
2226
June1st to 15thDay
36%5%14%27%15%1
2145
16th to endDay
26%5%14%32%18%2
2145
July1st to 15thDay
34%5%14%29%14%2
2006
16th to endDay
29%415%35%13%1
2129
August1st to 15thDay
29%416%26%20%1
2131
16th to endDay
31%414%26%15%6%
2198
September1st to 15thDay
40%210%22%16%6%
1890
16th to endDay
30%38%32%21%3
1815
October1st to 15thDay
34%310%26%20%4
1666
16th to endDay
31%210%28%20%5%
1760
November1st to 15thDay
27%311%29%21%6%
1692
16th to endDay
33%19%30%23%1
1581
December1st to 15thDay
42%212%29%13%
1440
16th to endDay
44%212%24%12%3
1728
January1st to 15thNight
33%210%28%21%3
2327
16th to endNight
31%212%31%17%3
2496
February1st to 15thNight
40%212%27%13%2
2288
16th to endNight
36%211%28%18%3
1898
March1st to 15thNight
39%39%23%17%5%
1980
16th to endNight
42%412%23%15%1
2112
April1st to 15thNight
34%310%26%22%3
1880
16th to endNight
40%311%24%17%2
1660
May1st to 15thNight
39%413%24%16%1
1485
16th to endNight
37%418%24%13%1
1541
June1st to 15thNight
27%415%33%16%1
1485
16th to endNight
20%316%35%20%2
1485
July1st to 15thNight
27%313%32%17%3
1395
16th to endNight
23%5%15%30%23%1
1468
August1st to 15thNight
24%5%13%32%19%4
1475
16th to endNight
25%312%31%19%7%
1652
September1st to 15thNight
34%311%22%19%8%
1737
16th to endNight
26%310%28%27%3
1815
October1st to 15thNight
33%28%22%23%7%
1952
16th to endNight
26%28%31%25%5%
2112
November1st to 15thNight
27%210%26%24%8%
2166
16th to endNight
33%28%29%22%4
2373
December1st to 15thNight
38%213%28%15%
2514
16th to endNight
41%211%25%13%5%
2496

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
24%17%31%21%5%
90
16th to endDay
18%11%36%27%5%1
96
February1st to 15thDay
7%23%44%18%5%
90
16th to endDay
12%17%45%13%9%1
81
March1st to 15thDay
21%20%41%15%2
90
16th to endDay
22%11%33%25%6%1
96
April1st to 15thDay
15%12%37%26%8%
186
16th to endDay
18%12%40%19%7%2
352
May1st to 15thDay
21%10%30%24%12%1
393
16th to endDay
20%6%26%28%13%4
437
June1st to 15thDay
8%5%24%33%24%3
420
16th to endDay
7%225%37%22%5%
420
July1st to 15thDay
12%220%37%23%4
400
16th to endDay
6%8%35%39%9%
445
August1st to 15thDay
6%210%33%37%8%
418
16th to endDay
8%114%31%35%8%
366
September1st to 15thDay
10%312%35%30%7%
165
16th to endDay
6%213%43%22%12%
90
October1st to 15thDay
8%5%31%32%6%15%
90
16th to endDay
10%5%42%30%9%2
96
November1st to 15thDay
14%423%26%24%6%
90
16th to endDay
34%17%27%15%22
90
December1st to 15thDay
14%13%47%15%5%3
90
16th to endDay
19%18%32%25%4
96
January1st to 15thNight
15%12%37%28%5%
900
16th to endNight
11%11%41%30%5%
960
February1st to 15thNight
14%14%37%30%2
880
16th to endNight
13%13%41%27%2
636
March1st to 15thNight
15%11%37%29%6%
540
16th to endNight
21%9%38%23%6%
576
April1st to 15thNight
14%12%35%30%5%
539
16th to endNight
18%7%37%28%8%
528
May1st to 15thNight
15%6%31%32%11%1
495
16th to endNight
12%428%33%18%2
515
June1st to 15thNight
6%423%44%21%
495
16th to endNight
4127%44%20%1
495
July1st to 15thNight
8%215%44%28%
465
16th to endNight
6%8%38%42%3
522
August1st to 15thNight
6%15%47%37%2
494
16th to endNight
7%10%40%38%2
525
September1st to 15thNight
11%316%40%24%3
495
16th to endNight
9%317%39%24%5%
492
October1st to 15thNight
16%327%30%19%2
632
16th to endNight
11%7%38%29%12%
704
November1st to 15thNight
11%10%33%29%13%1
766
16th to endNight
18%12%34%26%7%
900
December1st to 15thNight
19%10%36%28%5%
900
16th to endNight
17%10%35%30%5%
960
Page generated at 2017-04-27 16:48:59. Version ac04

Copyright 2017 A. Danko


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