Benton Harbor
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Benton Harbor clear sky chart from 2005-11-05 to 2017-09-16.

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
34%
15952
15%
46808
10%
15910
39%
15910
19%
33410

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
12%
900
7%
2506
2%
895
16%
895
9%
2107
January16th to endNight
14%
960
5%
2688
2%
960
16%
960
8%
2317
February1st to 15thNight
16%
733
8%
2178
3%
733
21%
733
10%
1766
February16th to endNight
19%
631
12%
1893
5%
631
25%
631
11%
1496
March1st to 15thNight
27%
720
14%
2157
8%
720
32%
720
17%
1556
March16th to endNight
31%
695
17%
2039
10%
695
38%
695
20%
1419
April1st to 15thNight
30%
539
14%
1797
10%
539
38%
539
18%
1235
April16th to endNight
36%
540
20%
1677
13%
540
43%
540
23%
1109
May1st to 15thNight
38%
540
16%
1620
10%
540
44%
540
24%
1090
May16th to endNight
50%
562
17%
1543
11%
561
54%
561
32%
984
June1st to 15thNight
54%
540
17%
1440
11%
540
59%
540
37%
878
June16th to endNight
54%
540
14%
1440
10%
540
57%
540
33%
918
July1st to 15thNight
65%
510
19%
1360
14%
510
67%
510
43%
796
July16th to endNight
68%
564
21%
1417
17%
531
70%
531
42%
824
August1st to 15thNight
71%
539
23%
1581
20%
536
74%
536
39%
892
August16th to endNight
63%
573
21%
1879
21%
573
67%
573
32%
1067
September1st to 15thNight
62%
588
26%
1848
24%
588
66%
588
33%
1061
September16th to endNight
54%
661
25%
1826
19%
661
57%
661
33%
1136
October1st to 15thNight
45%
660
23%
1834
17%
660
50%
660
28%
1189
October16th to endNight
22%
704
13%
2288
7%
704
29%
704
14%
1648
November1st to 15thNight
30%
700
19%
2276
13%
700
39%
700
18%
1558
November16th to endNight
21%
720
11%
2340
8%
720
25%
720
10%
1834
December1st to 15thNight
11%
873
5%
2493
2%
873
15%
873
7%
2151
December16th to endNight
10%
960
5%
2688
1%
960
13%
960
6%
2379

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
13%9%46%5%3445%7%35%
47956
Night
16%11%47%5%34446%32%
46976
Cloud CoverDay
14%9%46%5%3445%7%35%
47965
Night
16%10%47%5%34345%32%
46981
TransparencyDay
48%311%22%12%1
47642
Night
53%210%20%11%1
46808
SeeingDay
17%8%26%26%15%6%
5954
Night
22%8%25%28%12%1
15956

By Month

Percentage Cloud Cover NE (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
17%20%7%12%8%4433312%
1432
16th to endDay
14%18%10%12%11%35%33411%
1536
February1st to 15thDay
13%16%9%11%9%5%444417%
1681
16th to endDay
13%13%8%12%8%35%35%5%20%
1580
March1st to 15thDay
14%11%5%8%7%35%45%7%27%
1791
16th to endDay
17%8%36%5%3445%7%34%
2196
April1st to 15thDay
18%10%36%424336%35%
2151
16th to endDay
15%7%25%5%3445%6%39%
2283
May1st to 15thDay
16%8%36%4345%5%7%34%
2331
16th to endDay
10%425%5%25%5%6%8%43%
2570
June1st to 15thDay
9%5%25%43445%8%45%
2520
16th to endDay
8%424435%5%6%8%45%
2520
July1st to 15thDay
6%314435%5%5%9%50%
2520
16th to endDay
5%314425%5%6%11%49%
2655
August1st to 15thDay
6%325%435%5%6%8%47%
2368
16th to endDay
9%5%2442446%7%46%
2321
September1st to 15thDay
11%5%2442446%7%47%
2099
16th to endDay
11%6%35%42436%9%41%
1824
October1st to 15thDay
18%7%25%424445%39%
1792
16th to endDay
24%6%26%4445%5%6%28%
1584
November1st to 15thDay
17%12%25%423445%35%
1582
16th to endDay
19%18%5%10%5%24345%21%
1620
December1st to 15thDay
17%22%12%12%5%2331414%
1464
16th to endDay
21%19%10%10%7%2333413%
1536
January1st to 15thNight
20%18%7%11%8%3333415%
2506
16th to endNight
15%17%10%13%9%35%32413%
2688
February1st to 15thNight
15%15%7%13%7%44335%19%
2176
16th to endNight
16%15%7%10%7%3434423%
1893
March1st to 15thNight
17%12%48%5%24345%31%
2144
16th to endNight
16%8%37%5%35%447%33%
2039
April1st to 15thNight
18%8%45%5%345%5%6%32%
1797
16th to endNight
19%6%25%433346%38%
1677
May1st to 15thNight
17%7%36%4335%5%8%34%
1620
16th to endNight
12%5%26%42445%8%42%
1541
June1st to 15thNight
10%6%235%2446%9%46%
1440
16th to endNight
8%425%5%347%7%9%41%
1440
July1st to 15thNight
4224435%5%7%9%49%
1440
16th to endNight
7%3134245%7%8%52%
1513
August1st to 15thNight
6%3144345%6%9%50%
1590
16th to endNight
10%3144345%5%7%49%
1879
September1st to 15thNight
13%423423446%50%
1848
16th to endNight
12%6%25%324446%46%
1826
October1st to 15thNight
19%6%24324346%42%
1834
16th to endNight
27%9%36%42334430%
2288
November1st to 15thNight
17%13%46%324345%34%
2276
16th to endNight
21%19%5%8%42333422%
2340
December1st to 15thNight
23%21%11%9%5%1323313%
2493
16th to endNight
22%22%9%12%7%3322310%
2688

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
18%19%7%12%7%4443413%
1432
16th to endDay
14%19%11%12%11%3443312%
1536
February1st to 15thDay
13%16%9%12%9%35%33317%
1681
16th to endDay
14%14%8%11%7%45%445%19%
1580
March1st to 15thDay
14%12%5%9%5%3445%7%26%
1801
16th to endDay
18%8%26%5%2435%7%34%
2195
April1st to 15thDay
20%10%35%424346%35%
2151
16th to endDay
16%8%24424347%39%
2283
May1st to 15thDay
17%7%35%5%2445%6%34%
2331
16th to endDay
11%425%435%5%6%8%43%
2570
June1st to 15thDay
10%425%43445%7%46%
2520
16th to endDay
9%3245%25%5%6%8%46%
2520
July1st to 15thDay
7%4144345%5%8%50%
2520
16th to endDay
6%313425%5%6%11%49%
2655
August1st to 15thDay
6%4245%35%47%8%47%
2368
16th to endDay
10%5%25%4235%5%8%46%
2321
September1st to 15thDay
12%5%2442446%7%46%
2099
16th to endDay
12%5%25%42447%8%41%
1824
October1st to 15thDay
18%7%35%324445%40%
1792
16th to endDay
24%6%35%5%45%45%6%28%
1584
November1st to 15thDay
17%12%35%423435%36%
1582
16th to endDay
20%18%5%9%424345%21%
1620
December1st to 15thDay
18%22%13%12%42223314%
1464
16th to endDay
22%20%10%10%6%2334412%
1536
January1st to 15thNight
20%18%7%10%8%3433415%
2506
16th to endNight
15%17%10%13%9%3433413%
2688
February1st to 15thNight
15%16%7%12%8%4233420%
2169
16th to endNight
16%15%7%11%6%3423423%
1893
March1st to 15thNight
18%11%48%5%24345%32%
2157
16th to endNight
16%8%37%5%3445%6%33%
2039
April1st to 15thNight
19%8%36%5%3345%6%33%
1797
16th to endNight
20%5%25%433345%39%
1677
May1st to 15thNight
18%7%35%5%3345%7%35%
1619
16th to endNight
12%425%42446%8%43%
1541
June1st to 15thNight
10%5%135%2346%8%47%
1440
16th to endNight
8%425%436%6%6%9%42%
1440
July1st to 15thNight
5%223435%5%7%9%50%
1440
16th to endNight
7%213325%47%8%52%
1513
August1st to 15thNight
5%323435%45%8%51%
1590
16th to endNight
10%31443435%7%49%
1879
September1st to 15thNight
13%324323346%51%
1848
16th to endNight
12%5%25%324446%46%
1826
October1st to 15thNight
19%6%23333445%43%
1834
16th to endNight
27%9%36%423335%30%
2288
November1st to 15thNight
18%12%25%43334436%
2276
16th to endNight
22%19%6%7%32333423%
2340
December1st to 15thNight
22%21%10%9%5%2333313%
2493
16th to endNight
23%21%9%11%6%3332310%
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
76%211%7%2
1433
16th to endDay
77%28%7%3
1536
February1st to 15thDay
72%27%12%4
1683
16th to endDay
67%29%14%4
1580
March1st to 15thDay
58%114%17%7%
1801
16th to endDay
49%213%26%6%1
2196
April1st to 15thDay
51%28%21%14%
2151
16th to endDay
46%213%20%13%4
2283
May1st to 15thDay
49%312%24%10%
2331
16th to endDay
38%412%28%14%1
2574
June1st to 15thDay
36%311%27%19%1
2520
16th to endDay
35%414%24%18%2
2520
July1st to 15thDay
33%410%27%21%2
2371
16th to endDay
29%416%28%18%3
2488
August1st to 15thDay
33%312%30%18%2
2353
16th to endDay
35%413%26%16%2
2321
September1st to 15thDay
36%312%26%18%3
2099
16th to endDay
38%310%31%14%1
1824
October1st to 15thDay
46%29%26%14%
1792
16th to endDay
56%214%18%6%
1584
November1st to 15thDay
51%210%21%12%1
1582
16th to endDay
66%111%17%3
1620
December1st to 15thDay
76%17%10%2
1464
16th to endDay
76%210%8%2
1536
January1st to 15thNight
73%19%11%3
2506
16th to endNight
76%211%8%1
2688
February1st to 15thNight
69%19%13%5%
2178
16th to endNight
66%28%18%4
1893
March1st to 15thNight
55%212%18%9%1
2157
16th to endNight
51%213%23%7%1
2039
April1st to 15thNight
51%29%20%14%
1797
16th to endNight
47%29%20%15%4
1677
May1st to 15thNight
47%212%23%11%1
1620
16th to endNight
38%313%26%15%2
1543
June1st to 15thNight
34%212%29%18%2
1440
16th to endNight
37%416%23%16%1
1440
July1st to 15thNight
29%312%29%21%3
1360
16th to endNight
28%415%26%21%4
1417
August1st to 15thNight
30%312%29%21%2
1581
16th to endNight
34%310%27%19%4
1879
September1st to 15thNight
34%39%28%21%3
1848
16th to endNight
38%27%28%20%2
1826
October1st to 15thNight
42%28%26%18%1
1834
16th to endNight
57%111%19%7%1
2288
November1st to 15thNight
51%28%20%13%2
2276
16th to endNight
66%210%16%3
2340
December1st to 15thNight
77%17%11%2
2493
16th to endNight
80%18%7%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
22%18%35%17%5%
90
16th to endDay
30%9%36%18%41
96
February1st to 15thDay
20%31%35%10%3
90
16th to endDay
19%17%38%17%6%1
81
March1st to 15thDay
28%21%26%19%3
91
16th to endDay
31%11%26%18%9%2
288
April1st to 15thDay
30%10%28%21%7%1
270
16th to endDay
24%7%31%20%10%5%
270
May1st to 15thDay
26%10%28%20%10%4
288
16th to endDay
16%9%30%27%12%4
470
June1st to 15thDay
11%7%30%31%14%4
495
16th to endDay
10%6%34%29%13%5%
495
July1st to 15thDay
9%5%26%33%16%8%
475
16th to endDay
6%224%34%22%8%
515
August1st to 15thDay
9%118%29%26%14%
341
16th to endDay
16%415%27%25%11%
332
September1st to 15thDay
14%213%33%24%12%
315
16th to endDay
13%5%15%28%23%13%
257
October1st to 15thDay
18%6%22%28%21%2
233
16th to endDay
30%8%34%23%3
96
November1st to 15thDay
13%11%21%32%18%3
90
16th to endDay
34%13%37%8%5%
90
December1st to 15thDay
34%22%25%14%3
90
16th to endDay
23%36%36%21
96
January1st to 15thNight
30%15%31%18%4
900
16th to endNight
26%13%32%24%3
960
February1st to 15thNight
26%12%32%23%5%
736
16th to endNight
25%12%31%24%5%
631
March1st to 15thNight
25%12%29%24%8%
720
16th to endNight
20%8%32%29%8%1
695
April1st to 15thNight
23%10%30%26%8%
539
16th to endNight
22%6%30%28%9%2
540
May1st to 15thNight
21%427%31%12%1
540
16th to endNight
15%224%39%17%
563
June1st to 15thNight
14%220%41%19%1
540
16th to endNight
10%224%39%22%1
540
July1st to 15thNight
8%17%45%24%3
510
16th to endNight
9%13%41%31%4
564
August1st to 15thNight
7%11%45%29%5%
539
16th to endNight
12%212%34%32%5%
573
September1st to 15thNight
15%412%34%26%6%
588
16th to endNight
15%418%28%26%6%
661
October1st to 15thNight
22%5%20%30%19%1
660
16th to endNight
33%11%26%21%7%
704
November1st to 15thNight
26%9%28%24%10%
700
16th to endNight
35%12%24%21%5%
720
December1st to 15thNight
34%15%28%18%2
873
16th to endNight
33%13%32%16%2
960
Page generated at 2017-09-17 12:05:47. Version ac04

Copyright 2017 A. Danko


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