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 2018-04-23.

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%
16855
15%
49489
10%
16813
39%
16813
19%
35422

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%
975
7%
2716
2%
970
16%
970
9%
2293
January16th to endNight
14%
1040
6%
2912
2%
1040
17%
1040
9%
2484
February1st to 15thNight
15%
795
9%
2363
3%
795
21%
795
9%
1925
February16th to endNight
18%
683
12%
2049
5%
683
24%
683
11%
1624
March1st to 15thNight
27%
780
14%
2337
9%
780
32%
780
18%
1679
March16th to endNight
31%
753
18%
2209
11%
753
38%
753
21%
1526
April1st to 15thNight
29%
584
14%
1947
10%
584
36%
584
17%
1355
April16th to endNight
36%
558
20%
1732
14%
558
43%
558
23%
1149
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
55%
717
26%
1980
21%
717
59%
717
34%
1217
October1st to 15thNight
46%
720
22%
2001
16%
720
50%
720
28%
1310
October16th to endNight
23%
768
14%
2496
8%
768
30%
768
14%
1790
November1st to 15thNight
30%
760
18%
2471
13%
760
38%
760
18%
1715
November16th to endNight
21%
780
12%
2535
8%
780
26%
780
11%
1958
December1st to 15thNight
12%
946
5%
2701
2%
946
15%
946
7%
2312
December16th to endNight
10%
1040
5%
2912
1%
1040
13%
1040
5%
2575

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%
50033
Night
16%11%5%7%5%34446%31%
49657
Cloud CoverDay
14%9%46%5%2445%7%35%
50042
Night
16%11%47%5%34345%32%
49662
TransparencyDay
49%311%22%12%1
49719
Night
54%210%19%11%1
49489
SeeingDay
18%8%26%25%14%5%
6665
Night
23%8%25%28%12%1
16859

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%9%5%433312%
1552
16th to endDay
13%18%10%12%10%35%33412%
1664
February1st to 15thDay
15%15%8%11%10%4444416%
1825
16th to endDay
14%13%8%11%8%3435%5%20%
1710
March1st to 15thDay
14%11%5%8%7%35%45%7%27%
1941
16th to endDay
17%8%36%5%3445%7%34%
2379
April1st to 15thDay
18%10%36%423446%34%
2331
16th to endDay
15%7%35%5%3445%6%38%
2342
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%42%
1980
October1st to 15thDay
19%7%25%424445%38%
1955
16th to endDay
24%7%26%4445%5%6%28%
1728
November1st to 15thDay
18%12%25%424445%33%
1717
16th to endDay
18%17%5%9%5%24345%22%
1755
December1st to 15thDay
16%22%12%11%5%2332414%
1586
16th to endDay
20%20%9%10%8%2333412%
1664
January1st to 15thNight
19%17%7%11%9%3333414%
2716
16th to endNight
15%17%10%12%9%35%32414%
2912
February1st to 15thNight
15%15%7%13%8%44335%19%
2361
16th to endNight
18%15%7%10%7%3433423%
2049
March1st to 15thNight
16%11%5%7%5%23345%32%
2324
16th to endNight
15%8%47%5%35%45%7%33%
2209
April1st to 15thNight
19%8%45%5%3445%6%32%
1947
16th to endNight
18%7%26%434346%38%
1732
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
11%6%25%3245%5%6%47%
1980
October1st to 15thNight
19%6%24324345%41%
2001
16th to endNight
26%9%36%42323431%
2496
November1st to 15thNight
18%13%46%334345%33%
2471
16th to endNight
20%19%5%8%42323423%
2535
December1st to 15thNight
22%20%11%10%5%2323314%
2701
16th to endNight
22%21%8%12%8%3322310%
2912

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%18%7%12%9%4343413%
1552
16th to endDay
14%18%10%11%10%3443413%
1664
February1st to 15thDay
14%15%9%12%9%35%33317%
1825
16th to endDay
15%14%7%11%7%45%445%20%
1710
March1st to 15thDay
14%12%6%8%5%3445%7%27%
1951
16th to endDay
18%8%36%5%2445%7%33%
2378
April1st to 15thDay
20%10%35%423346%34%
2331
16th to endDay
16%8%24424347%39%
2342
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
11%5%25%42436%8%42%
1980
October1st to 15thDay
19%7%35%324445%39%
1955
16th to endDay
24%7%25%5%35%45%6%28%
1728
November1st to 15thDay
18%12%35%423436%34%
1717
16th to endDay
19%18%5%9%424345%22%
1755
December1st to 15thDay
17%21%13%12%42223414%
1586
16th to endDay
21%20%9%10%8%2324412%
1664
January1st to 15thNight
20%17%7%11%9%3433414%
2716
16th to endNight
15%17%10%13%9%3433415%
2912
February1st to 15thNight
15%16%7%12%8%4333419%
2354
16th to endNight
18%15%7%10%6%3423423%
2049
March1st to 15thNight
17%11%5%8%5%24335%33%
2337
16th to endNight
16%8%47%5%3445%6%33%
2209
April1st to 15thNight
20%9%36%5%3345%6%32%
1947
16th to endNight
19%6%25%433345%39%
1732
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%425%33445%6%47%
1980
October1st to 15thNight
19%6%23333445%42%
2001
16th to endNight
27%9%35%423335%31%
2496
November1st to 15thNight
19%13%35%43334434%
2471
16th to endNight
21%19%5%7%32322424%
2535
December1st to 15thNight
21%21%10%9%6%2333414%
2701
16th to endNight
22%21%9%11%7%3332310%
2912

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%210%8%2
1553
16th to endDay
75%210%7%3
1664
February1st to 15thDay
72%27%12%4
1827
16th to endDay
67%29%15%5%
1710
March1st to 15thDay
58%213%17%7%
1951
16th to endDay
49%213%26%6%1
2379
April1st to 15thDay
52%38%21%13%
2331
16th to endDay
46%212%20%13%4
2342
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
37%311%30%16%1
1980
October1st to 15thDay
47%29%25%13%1
1955
16th to endDay
56%213%18%7%
1728
November1st to 15thDay
52%210%20%11%1
1717
16th to endDay
64%111%18%3
1755
December1st to 15thDay
75%17%11%3
1586
16th to endDay
77%210%7%2
1664
January1st to 15thNight
73%19%10%3
2716
16th to endNight
74%211%9%1
2912
February1st to 15thNight
70%19%13%5%
2363
16th to endNight
66%28%17%4
2049
March1st to 15thNight
54%211%19%9%1
2337
16th to endNight
50%212%23%9%1
2209
April1st to 15thNight
53%29%20%13%
1947
16th to endNight
47%29%20%15%4
1732
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
36%27%29%21%2
1980
October1st to 15thNight
43%28%25%18%1
2001
16th to endNight
57%111%20%8%
2496
November1st to 15thNight
53%29%20%12%2
2471
16th to endNight
65%211%17%3
2535
December1st to 15thNight
76%17%11%2
2701
16th to endNight
80%18%7%1
2912

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
20%14%37%22%5%
135
16th to endDay
27%11%37%18%4
144
February1st to 15thDay
25%25%35%11%2
135
16th to endDay
23%17%40%13%4
120
March1st to 15thDay
25%22%27%19%22
136
16th to endDay
30%9%26%22%9%1
352
April1st to 15thDay
30%12%29%20%6%1
330
16th to endDay
24%7%30%20%12%5%
289
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
11%7%14%26%27%13%
314
October1st to 15thDay
22%421%29%19%2
291
16th to endDay
32%6%31%26%3
144
November1st to 15thDay
24%8%20%30%13%2
135
16th to endDay
28%17%37%11%5%
135
December1st to 15thDay
29%24%28%11%5%
135
16th to endDay
24%34%34%6%
144
January1st to 15thNight
29%14%32%18%4
975
16th to endNight
25%13%33%23%3
1040
February1st to 15thNight
27%11%32%23%5%
798
16th to endNight
26%12%32%23%4
683
March1st to 15thNight
24%11%29%25%7%
780
16th to endNight
19%7%33%29%8%1
753
April1st to 15thNight
25%9%30%25%8%
584
16th to endNight
22%6%30%29%9%1
558
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%27%6%
717
October1st to 15thNight
23%419%31%18%1
720
16th to endNight
33%11%26%21%7%
768
November1st to 15thNight
27%9%28%24%10%
760
16th to endNight
35%12%24%21%5%
780
December1st to 15thNight
33%15%29%18%3
946
16th to endNight
33%14%32%16%2
1040
Page generated at 2018-04-24 10:03:02. Version ac04

Copyright 2018 A. Danko


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