Hiawatha High School
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hiawatha High School clear sky chart from 2005-11-05 to 2017-08-12.

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
41%
15817
22%
46627
13%
15770
49%
15770
32%
27929

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%
900
22%
2327
8%
895
40%
895
31%
1480
January16th to endNight
27%
960
25%
2496
9%
960
38%
960
31%
1572
February1st to 15thNight
26%
879
15%
2288
5%
875
32%
875
23%
1629
February16th to endNight
28%
678
24%
1940
7%
678
41%
678
31%
1181
March1st to 15thNight
34%
540
22%
1980
13%
540
46%
540
26%
1116
March16th to endNight
25%
576
15%
2112
9%
576
34%
576
18%
1393
April1st to 15thNight
30%
539
20%
1872
12%
539
45%
539
26%
1077
April16th to endNight
31%
540
21%
1656
13%
540
44%
540
23%
1077
May1st to 15thNight
38%
539
19%
1620
14%
539
46%
539
25%
1050
May16th to endNight
43%
563
18%
1666
12%
561
49%
561
32%
1023
June1st to 15thNight
56%
540
19%
1440
10%
540
60%
540
41%
844
June16th to endNight
60%
540
24%
1458
13%
540
65%
540
51%
771
July1st to 15thNight
67%
510
17%
1530
13%
510
69%
510
41%
836
July16th to endNight
70%
564
24%
1594
22%
531
74%
531
44%
833
August1st to 15thNight
75%
527
23%
1575
25%
524
79%
524
43%
843
August16th to endNight
67%
525
24%
1630
26%
525
70%
525
38%
893
September1st to 15thNight
57%
495
25%
1727
25%
495
63%
495
30%
981
September16th to endNight
58%
492
29%
1815
25%
492
68%
492
38%
904
October1st to 15thNight
44%
635
28%
1955
20%
635
50%
635
34%
1116
October16th to endNight
37%
704
27%
2112
13%
704
48%
704
37%
1168
November1st to 15thNight
41%
811
29%
2211
13%
811
52%
811
41%
1227
November16th to endNight
32%
900
24%
2481
9%
900
44%
900
33%
1487
December1st to 15thNight
30%
900
19%
2520
7%
900
39%
900
25%
1657
December16th to endNight
28%
960
22%
2622
8%
960
39%
960
25%
1771

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
23%5%24423446%38%
47332
Night
22%5%14323345%43%
46823
Cloud CoverDay
10%6%35%42445%7%44%
47330
Night
10%5%2442345%7%49%
46823
TransparencyDay
38%5%13%24%14%2
47030
Night
34%413%26%17%3
46628
SeeingDay
13%6%28%30%17%3
5793
Night
12%8%32%32%11%1
15819

By Month

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
25%5%25%424435%35%
1611
16th to endDay
25%9%25%423245%33%
1728
February1st to 15thDay
26%5%36%5%33345%31%
1575
16th to endDay
25%7%26%423335%35%
1542
March1st to 15thDay
25%9%25%423345%32%
1980
16th to endDay
29%9%34423335%30%
2112
April1st to 15thDay
29%7%2432323435%
2076
16th to endDay
33%7%25%423446%26%
2301
May1st to 15thDay
27%5%25%32445%6%32%
2331
16th to endDay
28%5%245%23446%32%
2445
June1st to 15thDay
24%424424345%39%
2520
16th to endDay
19%2134245%6%7%42%
2498
July1st to 15thDay
23%3134235%7%7%36%
2340
16th to endDay
21%21332445%7%42%
2466
August1st to 15thDay
15%4234245%5%8%43%
2289
16th to endDay
16%315%433446%45%
2220
September1st to 15thDay
19%5%24424446%42%
1900
16th to endDay
15%424324346%48%
1815
October1st to 15thDay
19%5%2331324448%
1664
16th to endDay
17%423313345%50%
1760
November1st to 15thDay
20%41321233452%
1644
16th to endDay
26%7%23312345%40%
1476
December1st to 15thDay
27%7%37%5%23335%30%
1440
16th to endDay
27%8%37%42233431%
1599
January1st to 15thNight
22%5%2443333440%
2327
16th to endNight
24%6%26%322335%39%
2496
February1st to 15thNight
25%7%26%43334433%
2278
16th to endNight
21%7%2432345%6%37%
1940
March1st to 15thNight
24%6%14323335%40%
1980
16th to endNight
30%8%14423345%31%
2112
April1st to 15thNight
26%5%14323245%41%
1872
16th to endNight
30%6%24323346%31%
1656
May1st to 15thNight
28%5%24422246%36%
1619
16th to endNight
27%414323336%39%
1665
June1st to 15thNight
21%312223446%46%
1440
16th to endNight
18%12213448%51%
1458
July1st to 15thNight
21%31232235%8%44%
1620
16th to endNight
20%1332345%8%45%
1702
August1st to 15thNight
12%2332345%8%52%
1585
16th to endNight
14%314322436%52%
1630
September1st to 15thNight
17%5%23433346%46%
1727
16th to endNight
16%212313345%54%
1815
October1st to 15thNight
21%313312225%50%
1955
16th to endNight
17%423212225%54%
2112
November1st to 15thNight
19%312212345%52%
2211
16th to endNight
26%41222234445%
2481
December1st to 15thNight
27%7%25%32333436%
2520
16th to endNight
27%8%36%31122336%
2622

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%6%36%5%35%447%43%
1611
16th to endDay
10%9%46%334446%40%
1728
February1st to 15thDay
12%7%47%6%43446%37%
1575
16th to endDay
10%8%36%5%2445%6%41%
1542
March1st to 15thDay
11%10%47%5%35%45%6%37%
1980
16th to endDay
16%11%36%5%34445%34%
2110
April1st to 15thDay
14%9%25%42434443%
2076
16th to endDay
21%7%25%42335%8%33%
2301
May1st to 15thDay
13%7%36%5%25%5%6%6%36%
2331
16th to endDay
12%6%25%6%335%48%39%
2445
June1st to 15thDay
8%5%35%5%25%45%7%47%
2520
16th to endDay
5%2145%35%6%7%9%48%
2498
July1st to 15thDay
8%3245%246%8%9%44%
2340
16th to endDay
5%314435%5%6%8%51%
2466
August1st to 15thDay
7%4345%35%5%6%9%46%
2289
16th to endDay
9%425%5%345%5%7%47%
2220
September1st to 15thDay
11%5%24335%447%46%
1900
16th to endDay
6%5%1442445%6%53%
1815
October1st to 15thDay
11%5%23423345%52%
1664
16th to endDay
10%5%23323446%53%
1760
November1st to 15thDay
7%424313345%58%
1644
16th to endDay
11%8%3441245%6%46%
1476
December1st to 15thDay
10%9%47%6%35%447%37%
1440
16th to endDay
14%9%48%434346%36%
1599
January1st to 15thNight
7%6%35%5%34346%48%
2327
16th to endNight
8%7%36%423446%49%
2496
February1st to 15thNight
11%9%47%6%3445%5%37%
2278
16th to endNight
7%7%3432447%8%45%
1940
March1st to 15thNight
8%7%14425%447%48%
1980
16th to endNight
17%9%35%42345%6%36%
2112
April1st to 15thNight
12%6%24323347%49%
1872
16th to endNight
16%7%25%423447%41%
1656
May1st to 15thNight
13%6%35%5%3345%6%42%
1619
16th to endNight
10%43433435%8%48%
1665
June1st to 15thNight
5%4133245%5%8%54%
1440
16th to endNight
21123245%5%11%58%
1458
July1st to 15thNight
5%4234245%6%9%51%
1620
16th to endNight
321343447%10%54%
1702
August1st to 15thNight
331342446%9%54%
1585
16th to endNight
7%424423446%55%
1630
September1st to 15thNight
10%5%24424448%49%
1727
16th to endNight
8%31232345%6%58%
1815
October1st to 15thNight
12%424422345%54%
1955
16th to endNight
11%424212235%58%
2112
November1st to 15thNight
7%42322335%7%59%
2211
16th to endNight
11%5%23324346%51%
2481
December1st to 15thNight
12%8%25%433445%44%
2520
16th to endNight
14%9%46%422335%42%
2622

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
40%414%26%12%1
1612
16th to endDay
43%316%22%12%1
1728
February1st to 15thDay
47%415%22%8%1
1576
16th to endDay
42%414%21%15%1
1542
March1st to 15thDay
46%411%22%13%1
1980
16th to endDay
51%412%20%8%1
2112
April1st to 15thDay
43%411%22%16%
2076
16th to endDay
48%5%12%22%10%
2301
May1st to 15thDay
45%7%11%21%13%
2331
16th to endDay
42%6%15%23%10%1
2449
June1st to 15thDay
36%7%12%26%15%2
2520
16th to endDay
27%7%17%29%16%2
2498
July1st to 15thDay
32%7%15%28%12%3
2201
16th to endDay
27%6%15%31%16%2
2311
August1st to 15thDay
30%7%16%27%17%
2275
16th to endDay
35%5%11%23%17%5%
2220
September1st to 15thDay
36%6%12%20%19%4
1900
16th to endDay
31%5%11%27%22%1
1815
October1st to 15thDay
34%310%25%22%3
1664
16th to endDay
31%313%26%19%4
1760
November1st to 15thDay
27%411%28%22%4
1644
16th to endDay
37%310%29%16%
1476
December1st to 15thDay
46%5%15%23%9%
1440
16th to endDay
49%314%20%10%1
1599
January1st to 15thNight
36%414%26%17%
2327
16th to endNight
36%414%26%15%2
2496
February1st to 15thNight
47%412%21%11%1
2288
16th to endNight
35%414%23%17%4
1940
March1st to 15thNight
36%313%27%16%2
1980
16th to endNight
48%412%22%9%2
2112
April1st to 15thNight
36%310%28%18%2
1872
16th to endNight
43%411%24%15%
1656
May1st to 15thNight
42%411%23%15%1
1620
16th to endNight
34%6%17%25%14%1
1667
June1st to 15thNight
26%6%16%31%14%4
1440
16th to endNight
19%5%14%33%23%3
1458
July1st to 15thNight
26%5%16%29%18%4
1530
16th to endNight
22%5%15%32%21%1
1594
August1st to 15thNight
23%6%16%30%19%2
1575
16th to endNight
28%410%27%20%8%
1630
September1st to 15thNight
34%410%22%20%6%
1727
16th to endNight
25%411%29%25%3
1815
October1st to 15thNight
32%310%24%23%5%
1955
16th to endNight
30%310%27%23%4
2112
November1st to 15thNight
25%313%25%24%7%
2211
16th to endNight
33%311%29%19%2
2481
December1st to 15thNight
41%5%14%26%12%
2520
16th to endNight
44%412%23%12%2
2622

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%14%40%18%32
90
16th to endDay
15%14%44%20%4
96
February1st to 15thDay
12%23%40%18%5%
90
16th to endDay
14%17%40%16%9%1
81
March1st to 15thDay
14%21%40%21%12
90
16th to endDay
29%16%33%17%3
96
April1st to 15thDay
22%8%33%22%13%
195
16th to endDay
27%11%32%21%6%1
411
May1st to 15thDay
17%11%32%25%10%2
468
16th to endDay
17%6%37%25%11%2
517
June1st to 15thDay
8%5%25%34%21%4
495
16th to endDay
45%34%31%19%4
495
July1st to 15thDay
11%119%38%23%5%
475
16th to endDay
5%112%46%30%4
515
August1st to 15thDay
8%114%38%31%6%
474
16th to endDay
11%218%35%26%6%
388
September1st to 15thDay
10%224%37%22%4
175
16th to endDay
5%230%40%14%7%
90
October1st to 15thDay
7%11%30%36%410%
90
16th to endDay
6%7%43%34%6%2
96
November1st to 15thDay
6%432%28%23%4
90
16th to endDay
34%10%41%10%4
90
December1st to 15thDay
13%21%42%14%44
90
16th to endDay
28%18%28%22%2
96
January1st to 15thNight
11%13%39%27%6%
900
16th to endNight
14%12%41%26%6%
960
February1st to 15thNight
15%12%39%27%4
880
16th to endNight
12%11%42%26%6%
678
March1st to 15thNight
12%11%37%30%8%
540
16th to endNight
23%11%35%23%6%
576
April1st to 15thNight
15%11%39%28%5%
539
16th to endNight
21%10%34%25%7%
540
May1st to 15thNight
16%9%30%32%9%1
540
16th to endNight
12%434%32%13%1
563
June1st to 15thNight
9%325%44%16%1
540
16th to endNight
4230%45%16%1
540
July1st to 15thNight
6%117%47%24%2
510
16th to endNight
5%14%46%29%1
564
August1st to 15thNight
313%50%30%1
527
16th to endNight
7%315%40%28%5%
525
September1st to 15thNight
13%320%38%21%3
495
16th to endNight
8%325%39%20%2
492
October1st to 15thNight
15%6%29%32%14%1
635
16th to endNight
14%8%36%30%9%
704
November1st to 15thNight
9%13%32%33%10%
811
16th to endNight
13%13%37%27%7%1
900
December1st to 15thNight
17%14%33%27%5%
900
16th to endNight
18%10%36%28%6%
960
Page generated at 2017-08-13 13:16:46. Version ac04

Copyright 2017 A. Danko


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