Big Rapids
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Big Rapids clear sky chart from 2005-11-06 to 2024-01-12.

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
32%
24668
15%
74678
9%
24611
38%
24611
19%
52917

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 10thNight
16%
950
8%
2648
3%
946
20%
946
10%
2201
January11th to 20thNight
16%
906
7%
2535
2%
906
19%
906
8%
2144
January21st to endNight
18%
990
7%
2772
3%
990
22%
990
11%
2282
February1st to 10thNight
16%
762
8%
2350
4%
762
20%
762
9%
1913
February11th to 20thNight
18%
700
13%
2098
5%
699
26%
699
12%
1610
February21st to endNight
15%
592
12%
1776
3%
592
24%
592
13%
1359
March1st to 10thNight
27%
720
16%
2160
9%
720
33%
720
19%
1502
March11th to 20thNight
27%
720
21%
2033
10%
720
37%
720
24%
1354
March21st to endNight
26%
734
16%
2120
8%
734
34%
734
20%
1497
April1st to 10thNight
27%
540
15%
1800
8%
540
36%
540
17%
1222
April11th to 20thNight
29%
533
20%
1703
11%
533
40%
533
21%
1131
April21st to endNight
30%
540
18%
1620
7%
540
39%
540
22%
1079
May1st to 10thNight
32%
540
16%
1620
6%
540
40%
540
23%
1093
May11th to 20thNight
35%
531
19%
1566
10%
531
45%
531
26%
1021
May21st to endNight
44%
583
17%
1552
9%
582
51%
582
32%
1005
June1st to 10thNight
42%
540
15%
1440
8%
540
48%
540
34%
895
June11th to 20thNight
47%
540
17%
1440
10%
540
52%
540
35%
893
June21st to endNight
50%
540
18%
1440
10%
540
56%
540
37%
885
July1st to 10thNight
63%
525
18%
1400
14%
525
66%
525
46%
784
July11th to 20thNight
59%
522
21%
1392
15%
522
64%
522
43%
782
July21st to endNight
57%
591
20%
1487
13%
558
62%
558
42%
881
August1st to 10thNight
59%
537
21%
1556
16%
534
62%
534
38%
892
August11th to 20thNight
61%
534
24%
1598
18%
534
67%
534
39%
885
August21st to endNight
56%
594
23%
1913
19%
594
61%
594
34%
1092
September1st to 10thNight
56%
552
22%
1812
19%
552
62%
552
31%
1044
September11th to 20thNight
55%
720
28%
1980
21%
720
61%
720
38%
1172
September21st to endNight
46%
720
21%
1980
15%
720
50%
720
30%
1270
October1st to 10thNight
45%
720
23%
1980
16%
720
50%
720
30%
1265
October11th to 20thNight
29%
720
15%
2222
8%
720
36%
720
19%
1552
October21st to endNight
22%
792
14%
2574
8%
792
32%
792
16%
1874
November1st to 10thNight
29%
740
20%
2406
13%
740
39%
740
20%
1604
November11th to 20thNight
18%
760
13%
2470
6%
760
27%
760
13%
1844
November21st to endNight
21%
760
11%
2470
6%
760
27%
760
12%
1882
December1st to 10thNight
14%
930
6%
2640
2%
930
17%
930
9%
2205
December11th to 20thNight
14%
950
6%
3267
2%
949
19%
949
8%
2708
December21st to endNight
9%
1040
4%
4858
1%
1026
15%
1026
5%
4095

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
14%10%5%7%7%45%5%5%7%32%
74832
Night
15%11%5%8%6%35%45%7%32%
74899
TransparencyDay
52%311%21%12%1
74533
Night
53%311%21%11%1
74719
SeeingDay
18%15%31%22%11%4
14689
Night
19%11%31%28%10%1
24677

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 10thDay
14%16%8%13%10%5%5%46%5%14%
1517
11th to 20thDay
15%16%8%14%10%7%5%5%4410%
1448
21st to endDay
13%19%13%12%9%5%6%5%4411%
1584
February1st to 10thDay
12%14%7%11%12%6%7%6%45%16%
1606
11th to 20thDay
11%14%8%14%11%45%5%45%18%
1748
21st to endDay
12%16%8%11%8%45%5%5%5%20%
1480
March1st to 10thDay
14%11%6%10%7%45%5%47%28%
1800
11th to 20thDay
11%10%6%7%7%45%5%5%7%32%
1926
21st to endDay
17%12%5%7%6%45%45%6%30%
2250
April1st to 10thDay
18%13%6%7%6%3445%6%28%
2160
11th to 20thDay
18%11%36%6%3445%6%33%
2205
21st to endDay
16%11%37%7%35%45%7%33%
2340
May1st to 10thDay
16%9%36%5%35%46%7%36%
2340
11th to 20thDay
16%8%36%5%3446%7%38%
2327
21st to endDay
12%5%35%6%36%6%6%8%41%
2725
June1st to 10thDay
12%5%35%5%36%5%5%8%44%
2520
11th to 20thDay
13%5%25%5%35%5%6%8%42%
2520
21st to endDay
12%5%36%6%45%5%5%7%42%
2520
July1st to 10thDay
7%4245%35%5%7%10%49%
2520
11th to 20thDay
8%5%35%6%35%5%5%9%46%
2520
21st to endDay
9%425%6%36%5%6%9%45%
2743
August1st to 10thDay
9%6%35%7%36%6%6%10%40%
2373
11th to 20thDay
11%425%6%35%5%6%8%44%
2303
21st to endDay
11%6%25%5%35%5%7%8%44%
2440
September1st to 10thDay
13%5%26%5%36%5%6%9%40%
2129
11th to 20thDay
12%5%35%5%45%5%5%8%44%
1980
21st to endDay
14%7%36%6%4445%8%39%
1980
October1st to 10thDay
18%8%36%6%34446%38%
1980
11th to 20thDay
23%12%36%7%5%5%5%46%24%
1734
21st to endDay
22%13%38%8%45%5%5%5%23%
1782
November1st to 10thDay
13%11%47%6%35%45%7%34%
1672
11th to 20thDay
13%17%7%10%7%35%46%6%22%
1710
21st to endDay
21%18%7%8%6%43345%21%
1710
December1st to 10thDay
14%19%12%13%6%46%33415%
1539
11th to 20thDay
14%17%9%12%9%45%5%5%6%14%
1918
21st to endDay
24%20%8%11%8%444449%
2783
January1st to 10thNight
14%16%8%12%8%5%5%5%5%417%
2648
11th to 20thNight
16%17%8%11%8%5%5%45%5%15%
2535
21st to endNight
11%15%9%13%9%5%6%6%6%7%13%
2772
February1st to 10thNight
13%14%8%11%12%5%6%445%18%
2350
11th to 20thNight
13%12%6%11%9%45%5%5%6%24%
2098
21st to endNight
16%14%6%10%7%35%446%25%
1776
March1st to 10thNight
15%8%5%7%6%45%45%6%34%
2160
11th to 20thNight
12%10%46%5%35%45%6%39%
2033
21st to endNight
17%10%47%7%35%45%7%33%
2120
April1st to 10thNight
17%9%5%7%6%3445%6%35%
1800
11th to 20thNight
19%9%36%42445%7%37%
1703
21st to endNight
18%8%35%43446%7%37%
1620
May1st to 10thNight
13%7%46%6%5%6%5%6%9%35%
1620
11th to 20thNight
16%7%35%44446%8%39%
1565
21st to endNight
11%6%35%5%34447%46%
1551
June1st to 10thNight
12%5%35%5%3446%9%44%
1440
11th to 20thNight
11%5%36%4145%7%9%45%
1440
21st to endNight
9%5%35%5%346%5%9%48%
1440
July1st to 10thNight
6%4133245%6%9%56%
1440
11th to 20thNight
7%423435%5%5%9%54%
1440
21st to endNight
7%4345%35%5%6%8%52%
1575
August1st to 10thNight
8%425%43446%11%48%
1565
11th to 20thNight
8%3245%35%5%6%8%53%
1598
21st to endNight
11%6%25%4245%47%51%
1913
September1st to 10thNight
9%4245%45%46%7%50%
1812
11th to 20thNight
12%424324448%51%
1980
21st to endNight
15%6%25%43445%9%42%
1980
October1st to 10thNight
18%7%2442345%6%45%
1980
11th to 20thNight
20%10%46%5%345%5%7%32%
2222
21st to endNight
23%12%46%6%34346%30%
2574
November1st to 10thNight
12%12%47%435%5%5%7%36%
2406
11th to 20thNight
15%14%5%10%6%45%5%5%7%24%
2470
21st to endNight
18%15%7%8%6%345%46%23%
2470
December1st to 10thNight
15%16%9%12%9%46%445%16%
2640
11th to 20thNight
15%18%7%14%7%45%5%5%5%15%
3279
21st to endNight
26%21%7%11%6%3434412%
4884

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 10thDay
73%39%11%4
1518
11th to 20thDay
78%5%6%9%2
1448
21st to endDay
78%36%9%4
1584
February1st to 10thDay
70%47%15%3
1606
11th to 20thDay
68%38%13%8%1
1758
21st to endDay
67%49%15%6%1
1480
March1st to 10thDay
57%211%19%8%1
1800
11th to 20thDay
53%211%18%12%2
1926
21st to endDay
56%39%20%10%1
2250
April1st to 10thDay
57%39%19%11%
2160
11th to 20thDay
53%29%19%14%2
2205
21st to endDay
52%312%17%14%2
2340
May1st to 10thDay
48%310%25%13%2
2340
11th to 20thDay
46%312%22%15%2
2331
21st to endDay
41%412%27%15%1
2725
June1st to 10thDay
39%310%29%16%2
2520
11th to 20thDay
40%312%24%19%1
2520
21st to endDay
41%313%25%16%2
2520
July1st to 10thDay
31%412%31%18%4
2451
11th to 20thDay
35%410%30%19%2
2445
21st to endDay
36%412%27%19%3
2591
August1st to 10thDay
40%411%30%13%2
2358
11th to 20thDay
37%5%12%28%16%2
2303
21st to endDay
37%412%27%18%2
2440
September1st to 10thDay
41%413%27%14%2
2129
11th to 20thDay
39%312%32%13%1
1980
21st to endDay
45%312%27%13%
1980
October1st to 10thDay
49%38%25%14%1
1980
11th to 20thDay
62%211%19%5%
1734
21st to endDay
64%312%15%6%
1782
November1st to 10thDay
51%312%23%10%1
1672
11th to 20thDay
63%312%16%5%
1710
21st to endDay
68%212%13%4
1710
December1st to 10thDay
74%28%13%2
1539
11th to 20thDay
71%312%11%2
1915
21st to endDay
80%27%8%3
2783
January1st to 10thNight
70%49%13%5%
2648
11th to 20thNight
72%49%9%5%
2535
21st to endNight
70%311%11%5%
2772
February1st to 10thNight
70%37%15%5%
2350
11th to 20thNight
62%38%17%9%1
2099
21st to endNight
62%311%16%8%1
1776
March1st to 10thNight
51%312%23%10%1
2160
11th to 20thNight
45%312%23%14%3
2033
21st to endNight
53%210%23%11%1
2120
April1st to 10thNight
51%38%22%15%1
1800
11th to 20thNight
48%38%22%17%2
1703
21st to endNight
48%211%22%13%4
1620
May1st to 10thNight
47%311%24%12%2
1620
11th to 20thNight
44%310%22%18%3
1566
21st to endNight
39%410%29%16%2
1552
June1st to 10thNight
36%312%29%17%2
1440
11th to 20thNight
36%314%24%22%1
1440
21st to endNight
34%414%30%16%2
1440
July1st to 10thNight
26%412%33%21%4
1400
11th to 20thNight
28%315%33%18%2
1392
21st to endNight
30%416%28%20%3
1487
August1st to 10thNight
32%415%35%13%2
1556
11th to 20thNight
30%315%34%17%1
1598
21st to endNight
33%411%28%21%2
1913
September1st to 10thNight
35%410%31%19%2
1812
11th to 20thNight
33%212%37%14%1
1980
21st to endNight
40%414%31%11%1
1980
October1st to 10thNight
41%39%30%16%2
1980
11th to 20thNight
53%313%23%8%1
2222
21st to endNight
58%211%19%9%
2574
November1st to 10thNight
48%410%25%13%1
2406
11th to 20thNight
60%414%17%6%1
2470
21st to endNight
63%214%16%41
2470
December1st to 10thNight
71%39%12%4
2640
11th to 20thNight
71%312%10%4
3281
21st to endNight
77%210%8%4
4884

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 10thDay
22%18%35%20%5%1
270
11th to 20thDay
26%19%36%14%5%
243
21st to endDay
21%20%37%17%4
264
February1st to 10thDay
18%29%34%18%1
240
11th to 20thDay
19%32%36%11%2
240
21st to endDay
27%33%31%9%1
198
March1st to 10thDay
24%26%37%10%3
240
11th to 20thDay
21%16%30%24%7%2
366
21st to endDay
26%16%32%19%5%1
462
April1st to 10thDay
25%17%33%20%5%1
420
11th to 20thDay
27%20%30%14%7%2
412
21st to endDay
23%16%30%22%9%1
420
May1st to 10thDay
23%18%30%18%6%3
423
11th to 20thDay
20%14%31%23%10%3
473
21st to endDay
15%13%32%26%12%4
679
June1st to 10thDay
12%12%38%25%10%3
630
11th to 20thDay
16%11%32%28%9%4
630
21st to endDay
13%11%35%26%11%3
630
July1st to 10thDay
8%9%28%31%18%6%
621
11th to 20thDay
8%11%29%29%17%7%
618
21st to endDay
9%8%33%28%15%7%
684
August1st to 10thDay
10%8%27%24%22%9%
492
11th to 20thDay
12%5%21%28%21%12%
439
21st to endDay
15%7%23%29%19%7%
495
September1st to 10thDay
15%9%24%26%18%8%
450
11th to 20thDay
11%8%23%28%23%8%
450
21st to endDay
18%14%21%26%16%6%
450
October1st to 10thDay
21%13%28%21%15%2
450
11th to 20thDay
28%19%29%20%5%
356
21st to endDay
31%20%30%13%42
297
November1st to 10thDay
23%20%34%17%5%1
270
11th to 20thDay
20%24%39%13%3
270
21st to endDay
31%22%29%13%4
270
December1st to 10thDay
25%26%31%13%4
270
11th to 20thDay
24%24%37%13%2
270
21st to endDay
27%25%34%11%31
297
January1st to 10thNight
21%19%34%20%6%1
950
11th to 20thNight
24%15%34%22%5%
906
21st to endNight
19%11%36%28%6%
990
February1st to 10thNight
19%16%36%26%3
762
11th to 20thNight
21%15%37%23%4
703
21st to endNight
25%19%34%19%3
592
March1st to 10thNight
18%14%35%25%8%1
720
11th to 20thNight
18%15%36%24%7%1
720
21st to endNight
21%13%34%25%7%
734
April1st to 10thNight
21%14%33%26%5%1
540
11th to 20thNight
27%11%31%25%6%1
533
21st to endNight
21%13%32%26%7%1
540
May1st to 10thNight
16%11%35%29%8%1
540
11th to 20thNight
18%8%33%29%10%1
531
21st to endNight
13%7%31%31%17%1
584
June1st to 10thNight
13%9%30%34%13%1
540
11th to 20thNight
13%7%28%39%14%1
540
21st to endNight
10%428%41%15%1
540
July1st to 10thNight
6%321%42%24%3
525
11th to 20thNight
7%6%23%42%20%2
522
21st to endNight
9%226%41%21%1
591
August1st to 10thNight
8%323%43%21%2
537
11th to 20thNight
10%220%38%25%5%
534
21st to endNight
14%321%40%20%2
594
September1st to 10thNight
9%6%24%37%19%4
552
11th to 20thNight
13%6%22%34%22%3
720
21st to endNight
17%9%24%30%17%3
720
October1st to 10thNight
21%8%24%32%14%1
720
11th to 20thNight
25%13%30%26%6%1
720
21st to endNight
30%11%31%21%6%1
792
November1st to 10thNight
18%15%32%27%7%1
740
11th to 20thNight
22%16%37%20%5%
760
21st to endNight
25%14%31%25%4
760
December1st to 10thNight
22%18%33%23%3
930
11th to 20thNight
25%15%37%18%41
950
21st to endNight
31%14%35%19%2
1045
Page generated at 2024-01-08 22:31:27. Version ac07

Copyright 2024 Attilla Danko


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