Hannibal
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hannibal clear sky chart from 2005-11-05 to 2017-12-02.

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
40%
16210
21%
47821
13%
16163
48%
16163
28%
30125

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
26%
900
19%
2479
8%
895
36%
895
25%
1660
January16th to endNight
21%
960
19%
2496
5%
960
31%
960
23%
1715
February1st to 15thNight
24%
880
12%
2288
3%
876
30%
876
20%
1641
February16th to endNight
26%
634
22%
1896
8%
634
38%
634
25%
1205
March1st to 15thNight
27%
618
19%
2058
9%
618
38%
618
21%
1332
March16th to endNight
27%
576
14%
2061
10%
576
35%
576
16%
1422
April1st to 15thNight
30%
539
20%
1797
12%
539
43%
539
25%
1095
April16th to endNight
38%
540
21%
1800
17%
540
48%
540
24%
1157
May1st to 15thNight
38%
539
19%
1601
13%
539
45%
539
25%
1054
May16th to endNight
47%
563
22%
1497
13%
561
54%
561
32%
973
June1st to 15thNight
61%
540
20%
1440
13%
540
64%
540
42%
846
June16th to endNight
59%
540
20%
1440
12%
540
63%
540
38%
875
July1st to 15thNight
65%
510
18%
1360
14%
510
67%
510
38%
838
July16th to endNight
73%
564
25%
1508
23%
531
75%
531
45%
828
August1st to 15thNight
77%
539
24%
1621
27%
536
78%
536
43%
881
August16th to endNight
74%
573
24%
1910
28%
573
77%
573
38%
1022
September1st to 15thNight
64%
540
29%
1800
30%
540
69%
540
35%
1000
September16th to endNight
60%
633
32%
1947
23%
633
68%
633
38%
1066
October1st to 15thNight
46%
720
28%
2160
19%
720
53%
720
35%
1248
October16th to endNight
34%
768
27%
2304
15%
768
46%
768
31%
1367
November1st to 15thNight
35%
760
25%
2464
14%
760
48%
760
28%
1426
November16th to endNight
28%
904
23%
2659
11%
904
39%
904
28%
1670
December1st to 15thNight
25%
910
15%
2547
6%
910
33%
910
21%
1817
December16th to endNight
21%
960
15%
2688
4%
960
30%
960
16%
1987

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%6%35%5%3445%7%40%
48633
Night
12%6%35%424446%44%
48004
TransparencyDay
42%412%24%14%2
48319
Night
40%311%25%16%2
47823
SeeingDay
14%6%24%29%18%5%
6163
Night
16%8%29%31%13%1
16211

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
12%10%48%6%34446%35%
1458
16th to endDay
14%11%47%6%34346%32%
1728
February1st to 15thDay
14%8%38%5%36%5%46%33%
1575
16th to endDay
12%9%36%5%35%45%5%36%
1576
March1st to 15thDay
13%10%47%6%24445%35%
1912
16th to endDay
17%9%36%6%345%46%32%
2161
April1st to 15thDay
16%8%36%5%33246%39%
2151
16th to endDay
19%5%26%6%2335%7%35%
2160
May1st to 15thDay
17%6%45%6%3445%7%33%
2346
16th to endDay
13%5%36%5%35%5%6%7%38%
2617
June1st to 15thDay
6%435%436%6%7%9%42%
2520
16th to endDay
8%424435%5%5%11%44%
2520
July1st to 15thDay
6%3144346%8%10%45%
2520
16th to endDay
5%3245%26%5%7%10%45%
2554
August1st to 15thDay
7%4145%35%6%7%9%44%
2328
16th to endDay
9%325%435%5%6%8%45%
2292
September1st to 15thDay
12%5%1343345%7%48%
2160
16th to endDay
8%3245%345%47%50%
1998
October1st to 15thDay
15%6%24323346%47%
1800
16th to endDay
14%6%24322435%49%
1920
November1st to 15thDay
16%5%25%223436%47%
1723
16th to endDay
17%7%44323436%41%
1628
December1st to 15thDay
18%9%45%6%3435%5%34%
1450
16th to endDay
18%11%46%424445%32%
1536
January1st to 15thNight
12%8%36%5%34346%40%
2479
16th to endNight
11%10%5%8%424346%38%
2496
February1st to 15thNight
14%10%45%6%34445%35%
2278
16th to endNight
14%7%25%324335%44%
1896
March1st to 15thNight
16%8%35%424335%41%
2058
16th to endNight
17%7%46%6%35%45%7%31%
2061
April1st to 15thNight
13%6%25%433436%45%
1797
16th to endNight
17%6%36%423445%42%
1800
May1st to 15thNight
14%6%35%6%3335%7%40%
1601
16th to endNight
10%5%26%5%2445%8%44%
1496
June1st to 15thNight
7%424434348%52%
1440
16th to endNight
8%215%435%5%6%9%47%
1440
July1st to 15thNight
7%3235%35%35%9%49%
1440
16th to endNight
5%2134235%5%8%55%
1612
August1st to 15thNight
4213335%5%6%9%53%
1631
16th to endNight
6%32442445%8%54%
1910
September1st to 15thNight
10%5%14323447%52%
1800
16th to endNight
5%3245%24347%54%
1947
October1st to 15thNight
11%414324336%52%
2160
16th to endNight
14%5%14323345%51%
2304
November1st to 15thNight
12%6%25%423335%51%
2464
16th to endNight
15%7%34323445%45%
2659
December1st to 15thNight
20%8%35%5%2445%5%34%
2547
16th to endNight
20%10%5%7%5%3434431%
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
49%39%23%13%
1459
16th to endDay
52%214%21%8%
1728
February1st to 15thDay
51%412%21%8%
1576
16th to endDay
49%213%22%11%
1576
March1st to 15thDay
50%311%24%8%1
1912
16th to endDay
51%5%14%19%8%
2163
April1st to 15thDay
47%29%25%13%1
2151
16th to endDay
47%312%22%12%1
2160
May1st to 15thDay
49%5%12%24%8%
2346
16th to endDay
43%5%12%21%14%2
2621
June1st to 15thDay
34%5%14%26%16%2
2520
16th to endDay
34%5%14%26%16%3
2520
July1st to 15thDay
32%5%16%28%13%3
2371
16th to endDay
30%6%14%30%16%1
2395
August1st to 15thDay
34%5%13%27%17%1
2314
16th to endDay
35%5%10%22%19%5%
2292
September1st to 15thDay
34%39%26%20%5%
2160
16th to endDay
31%39%32%20%2
1998
October1st to 15thDay
39%28%25%20%3
1800
16th to endDay
37%211%26%19%3
1920
November1st to 15thDay
39%210%22%21%3
1723
16th to endDay
44%311%27%11%
1628
December1st to 15thDay
52%214%20%9%
1450
16th to endDay
53%311%20%9%1
1536
January1st to 15thNight
45%210%26%14%
2479
16th to endNight
47%214%23%11%
2496
February1st to 15thNight
51%212%20%10%1
2288
16th to endNight
43%213%26%13%1
1896
March1st to 15thNight
46%210%25%12%2
2058
16th to endNight
52%411%21%8%
2061
April1st to 15thNight
40%310%25%16%3
1797
16th to endNight
43%48%24%15%3
1800
May1st to 15thNight
43%412%22%16%
1602
16th to endNight
38%5%12%22%19%3
1498
June1st to 15thNight
29%315%29%20%2
1440
16th to endNight
31%5%12%26%20%4
1440
July1st to 15thNight
33%411%27%19%4
1360
16th to endNight
25%413%34%19%2
1508
August1st to 15thNight
25%5%12%32%20%3
1621
16th to endNight
27%412%25%22%6%
1910
September1st to 15thNight
31%37%24%25%6%
1800
16th to endNight
29%38%29%26%2
1947
October1st to 15thNight
33%38%26%22%5%
2160
16th to endNight
35%37%26%21%3
2304
November1st to 15thNight
36%310%24%19%6%
2464
16th to endNight
40%210%29%16%
2659
December1st to 15thNight
51%212%21%10%
2547
16th to endNight
56%310%18%9%1
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
30%11%41%15%2
90
16th to endDay
16%17%44%16%4
96
February1st to 15thDay
15%22%36%17%7%
90
16th to endDay
16%20%27%29%41
81
March1st to 15thDay
23%14%44%14%3
90
16th to endDay
25%15%31%21%5%
147
April1st to 15thDay
20%13%28%23%13%
270
16th to endDay
24%331%28%10%1
270
May1st to 15thDay
21%9%32%23%9%3
405
16th to endDay
18%7%30%26%11%5%
517
June1st to 15thDay
8%423%33%23%6%
495
16th to endDay
10%5%26%34%17%4
495
July1st to 15thDay
8%220%39%22%7%
475
16th to endDay
7%114%33%33%9%
515
August1st to 15thDay
8%112%37%31%8%
481
16th to endDay
8%212%31%32%12%
332
September1st to 15thDay
13%310%31%30%11%
315
16th to endDay
8%418%32%25%11%
260
October1st to 15thDay
21%13%17%29%12%5%
135
16th to endDay
18%9%31%30%9%
144
November1st to 15thDay
12%5%31%25%16%7%
135
16th to endDay
31%14%26%18%8%
135
December1st to 15thDay
22%13%35%18%6%4
94
16th to endDay
30%16%40%11%1
96
January1st to 15thNight
16%13%38%24%6%
900
16th to endNight
17%15%39%24%3
960
February1st to 15thNight
19%13%36%27%3
880
16th to endNight
19%13%36%27%2
634
March1st to 15thNight
21%11%35%24%6%
618
16th to endNight
21%10%31%28%6%
576
April1st to 15thNight
16%12%37%26%6%
539
16th to endNight
20%5%30%35%7%
540
May1st to 15thNight
17%5%29%36%11%
540
16th to endNight
11%329%35%18%1
563
June1st to 15thNight
8%220%43%23%1
540
16th to endNight
10%220%44%20%2
540
July1st to 15thNight
10%112%41%30%3
510
16th to endNight
6%111%39%38%2
564
August1st to 15thNight
6%8%43%36%3
539
16th to endNight
6%19%38%38%5%
573
September1st to 15thNight
14%114%37%25%6%
540
16th to endNight
9%419%33%27%6%
633
October1st to 15thNight
14%5%27%31%17%3
720
16th to endNight
18%7%35%27%10%
768
November1st to 15thNight
15%9%35%29%9%
760
16th to endNight
20%9%38%24%6%
904
December1st to 15thNight
24%11%34%24%4
910
16th to endNight
25%12%33%23%4
960
Page generated at 2017-12-03 10:16:43. Version ac04

Copyright 2017 A. Danko


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