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 2017-12-04.

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
43%
16160
25%
48056
15%
16114
52%
16114
34%
27811

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%
540
21%
1696
14%
540
44%
540
26%
1048
May1st to 15thNight
39%
539
21%
1620
16%
539
47%
539
29%
1013
May16th to endNight
46%
563
20%
1685
17%
561
53%
561
31%
1014
June1st to 15thNight
62%
540
18%
1620
13%
540
67%
540
40%
900
June16th to endNight
61%
540
22%
1620
16%
540
66%
540
49%
819
July1st to 15thNight
69%
510
20%
1530
17%
510
70%
510
43%
831
July16th to endNight
76%
564
26%
1594
27%
531
78%
531
45%
836
August1st to 15thNight
76%
539
25%
1610
30%
536
77%
536
42%
856
August16th to endNight
72%
573
28%
1803
31%
573
74%
573
43%
928
September1st to 15thNight
63%
540
26%
1895
30%
540
65%
540
33%
1037
September16th to endNight
63%
537
32%
1980
30%
537
72%
537
37%
986
October1st to 15thNight
46%
690
28%
2130
20%
690
52%
690
33%
1227
October16th to endNight
40%
768
33%
2304
17%
768
53%
768
42%
1197
November1st to 15thNight
39%
832
29%
2352
14%
832
51%
832
39%
1311
November16th to endNight
32%
975
28%
2571
11%
975
44%
975
35%
1544
December1st to 15thNight
31%
920
21%
2569
9%
920
40%
920
31%
1610
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%24424447%46%
48424
Night
10%5%24323347%51%
48251
TransparencyDay
37%312%27%15%2
48124
Night
33%311%28%19%4
48056
SeeingDay
13%6%24%30%20%4
6095
Night
13%8%30%32%14%1
16162

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
18%7%37%434335%37%
2262
May1st to 15thDay
19%7%35%434446%36%
2331
16th to endDay
15%6%26%436%5%5%8%34%
2430
June1st to 15thDay
9%425%5%3445%8%46%
2340
16th to endDay
6%212425%47%9%52%
2340
July1st to 15thDay
9%414425%5%6%9%45%
2340
16th to endDay
6%314435%5%7%9%47%
2466
August1st to 15thDay
6%3235%35%5%6%11%47%
2340
16th to endDay
7%42442446%7%50%
2399
September1st to 15thDay
13%5%245%23336%48%
2062
16th to endDay
9%41342445%7%52%
1980
October1st to 15thDay
13%5%24323336%51%
1817
16th to endDay
11%414323345%55%
1920
November1st to 15thDay
10%5%13313346%55%
1836
16th to endDay
15%5%13212235%56%
1713
December1st to 15thDay
15%7%35%5%12347%43%
1467
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
16%5%35%422446%45%
1696
May1st to 15thNight
14%5%25%423446%46%
1619
16th to endNight
11%424425%45%10%45%
1683
June1st to 15thNight
6%3224345%5%10%52%
1620
16th to endNight
421232445%9%59%
1620
July1st to 15thNight
6%315%3245%5%10%52%
1620
16th to endNight
5%1133345%6%10%52%
1702
August1st to 15thNight
5%2143246%5%8%55%
1620
16th to endNight
6%314424348%57%
1803
September1st to 15thNight
10%424424446%52%
1895
16th to endNight
7%32332345%7%56%
1980
October1st to 15thNight
15%424323335%53%
2130
16th to endNight
8%413313346%60%
2304
November1st to 15thNight
11%423212336%57%
2352
16th to endNight
14%5%23213235%54%
2571
December1st to 15thNight
15%6%2422245%7%45%
2569
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
48%310%23%12%1
2262
May1st to 15thDay
48%311%22%12%
2331
16th to endDay
46%5%14%22%9%1
2434
June1st to 15thDay
35%5%13%27%16%1
2340
16th to endDay
25%5%14%32%19%2
2340
July1st to 15thDay
33%5%14%30%14%1
2201
16th to endDay
28%5%16%33%14%1
2311
August1st to 15thDay
30%5%16%26%19%1
2326
16th to endDay
30%414%26%17%6%
2399
September1st to 15thDay
37%210%25%17%6%
2062
16th to endDay
30%38%33%20%3
1980
October1st to 15thDay
34%310%25%21%5%
1817
16th to endDay
30%210%28%21%6%
1920
November1st to 15thDay
30%311%28%20%6%
1836
16th to endDay
32%19%30%24%1
1713
December1st to 15thDay
42%212%29%12%
1467
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%23%17%2
1696
May1st to 15thNight
39%412%24%18%1
1620
16th to endNight
36%418%25%13%1
1685
June1st to 15thNight
27%5%14%33%17%2
1620
16th to endNight
21%316%34%20%2
1620
July1st to 15thNight
27%313%33%18%3
1530
16th to endNight
23%5%14%30%23%2
1594
August1st to 15thNight
25%5%14%33%18%4
1610
16th to endNight
25%311%30%21%7%
1803
September1st to 15thNight
32%310%25%18%7%
1895
16th to endNight
26%410%30%25%3
1980
October1st to 15thNight
34%28%22%23%8%
2130
16th to endNight
25%28%30%26%6%
2304
November1st to 15thNight
29%210%26%22%8%
2352
16th to endNight
33%28%28%23%3
2571
December1st to 15thNight
38%214%28%15%
2569
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
20%11%38%19%7%2
372
May1st to 15thDay
19%9%29%26%12%1
468
16th to endDay
19%8%28%28%11%3
517
June1st to 15thDay
8%5%24%33%24%4
495
16th to endDay
7%327%37%20%4
495
July1st to 15thDay
11%217%37%25%5%
475
16th to endDay
6%7%34%40%9%
515
August1st to 15thDay
8%210%34%35%8%
493
16th to endDay
7%114%34%34%8%
439
September1st to 15thDay
8%211%34%32%10%
217
16th to endDay
8%215%43%20%8%
135
October1st to 15thDay
12%5%37%28%5%11%
135
16th to endDay
11%9%44%25%8%1
144
November1st to 15thDay
22%5%22%25%18%4
135
16th to endDay
25%16%30%16%9%1
135
December1st to 15thDay
14%13%46%16%7%4
100
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
19%7%36%28%8%
540
May1st to 15thNight
15%6%31%32%12%1
540
16th to endNight
12%429%32%18%2
563
June1st to 15thNight
5%422%44%22%
540
16th to endNight
4227%44%19%1
540
July1st to 15thNight
8%214%45%28%1
510
16th to endNight
6%8%38%43%3
564
August1st to 15thNight
7%15%46%37%2
539
16th to endNight
7%10%41%36%2
573
September1st to 15thNight
10%315%40%26%3
540
16th to endNight
9%218%39%24%5%
537
October1st to 15thNight
17%427%30%18%1
690
16th to endNight
10%7%37%30%11%
768
November1st to 15thNight
13%9%33%28%12%1
832
16th to endNight
18%12%34%26%7%
975
December1st to 15thNight
19%10%35%28%5%
920
16th to endNight
17%10%35%30%5%
960
Page generated at 2017-12-05 09:18:59. Version ac04

Copyright 2017 A. Danko


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