Saginaw
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Saginaw clear sky chart from 2005-11-05 to 2017-09-17.

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
37%
15723
15%
46892
10%
15682
43%
15682
21%
32498

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
17%
898
8%
2506
2%
895
22%
895
12%
1998
January16th to endNight
23%
912
9%
2640
4%
912
28%
912
12%
2083
February1st to 15thNight
21%
702
11%
2258
4%
701
28%
701
12%
1720
February16th to endNight
25%
631
14%
1893
6%
631
34%
631
14%
1417
March1st to 15thNight
30%
720
16%
2092
10%
720
35%
720
20%
1484
March16th to endNight
35%
768
18%
2112
11%
768
42%
768
23%
1479
April1st to 15thNight
30%
563
15%
1790
10%
563
35%
563
20%
1226
April16th to endNight
37%
540
21%
1620
10%
540
47%
540
26%
1066
May1st to 15thNight
38%
540
15%
1620
9%
540
44%
540
22%
1093
May16th to endNight
47%
562
16%
1618
10%
561
54%
561
30%
1036
June1st to 15thNight
50%
411
15%
1311
14%
411
54%
411
29%
781
June16th to endNight
59%
427
16%
1327
14%
427
63%
427
31%
791
July1st to 15thNight
66%
510
17%
1360
14%
510
68%
510
43%
795
July16th to endNight
63%
564
18%
1456
16%
531
65%
531
39%
866
August1st to 15thNight
67%
539
20%
1609
16%
536
70%
536
36%
936
August16th to endNight
61%
573
22%
1746
17%
573
65%
573
35%
994
September1st to 15thNight
58%
651
22%
1911
17%
651
62%
651
34%
1134
September16th to endNight
59%
665
22%
1837
17%
665
61%
665
34%
1120
October1st to 15thNight
45%
660
20%
1890
17%
660
49%
660
26%
1252
October16th to endNight
28%
704
13%
2230
8%
704
35%
704
16%
1622
November1st to 15thNight
36%
700
19%
2276
15%
700
42%
700
20%
1527
November16th to endNight
25%
720
12%
2409
7%
720
32%
720
14%
1782
December1st to 15thNight
17%
803
8%
2603
3%
803
23%
803
11%
2023
December16th to endNight
17%
960
9%
2778
2%
960
23%
960
11%
2273

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%8%36%6%35%45%7%34%
47869
Night
15%8%46%5%3445%6%35%
47065
Cloud CoverDay
14%8%36%6%35%45%7%34%
47878
Night
15%8%46%5%3445%6%35%
47070
TransparencyDay
48%5%12%21%10%1
47560
Night
48%411%21%11%1
46892
SeeingDay
17%6%25%25%16%8%
5896
Night
19%6%27%31%12%1
15728

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%14%6%8%8%37%5%5%5%17%
1432
16th to endDay
15%17%8%10%8%5%5%44415%
1584
February1st to 15thDay
12%16%5%10%6%45%5%5%6%20%
1601
16th to endDay
12%12%6%8%8%46%45%6%23%
1580
March1st to 15thDay
15%10%37%8%43447%29%
1857
16th to endDay
16%9%47%8%44445%30%
2112
April1st to 15thDay
20%10%45%434346%31%
2166
16th to endDay
16%7%36%5%34446%37%
2340
May1st to 15thDay
19%7%35%424447%36%
2331
16th to endDay
11%5%35%5%35%46%7%41%
2495
June1st to 15thDay
11%6%26%5%345%6%7%40%
2646
16th to endDay
10%425%5%46%5%8%10%37%
2627
July1st to 15thDay
6%3245%35%5%6%9%46%
2520
16th to endDay
8%325%5%36%5%6%9%42%
2612
August1st to 15thDay
9%416%446%6%5%9%40%
2340
16th to endDay
10%5%25%5%35%46%7%43%
2455
September1st to 15thDay
11%425%435%5%5%8%42%
2037
16th to endDay
12%5%25%5%25%45%9%41%
1829
October1st to 15thDay
16%7%35%6%35%345%38%
1738
16th to endDay
22%8%46%6%34446%27%
1639
November1st to 15thDay
14%10%26%6%35%35%6%35%
1582
16th to endDay
16%12%48%6%36%447%24%
1548
December1st to 15thDay
15%15%5%10%7%35%35%423%
1356
16th to endDay
19%16%8%9%7%2345%6%16%
1442
January1st to 15thNight
21%13%5%9%7%34435%22%
2506
16th to endNight
14%12%8%9%7%45%5%5%5%20%
2640
February1st to 15thNight
13%14%410%6%35%445%26%
2256
16th to endNight
15%13%49%7%34445%26%
1893
March1st to 15thNight
16%9%46%5%2345%5%35%
2079
16th to endNight
14%8%46%5%2445%6%36%
2112
April1st to 15thNight
20%9%46%323447%34%
1790
16th to endNight
17%6%2442435%6%41%
1620
May1st to 15thNight
15%6%36%5%35%448%35%
1620
16th to endNight
12%325%5%345%5%7%44%
1616
June1st to 15thNight
10%6%25%33447%7%43%
1311
16th to endNight
8%4245%35%6%5%9%44%
1327
July1st to 15thNight
6%32442445%8%53%
1440
16th to endNight
6%2244245%5%8%50%
1555
August1st to 15thNight
7%3135%345%6%8%49%
1620
16th to endNight
9%5%14323447%53%
1746
September1st to 15thNight
10%424324446%51%
1911
16th to endNight
11%5%2442445%6%49%
1837
October1st to 15thNight
16%6%35%42435%6%41%
1890
16th to endNight
21%8%37%6%43445%30%
2230
November1st to 15thNight
14%8%35%5%34446%37%
2276
16th to endNight
21%11%46%6%35%45%6%25%
2409
December1st to 15thNight
18%15%7%8%5%33445%22%
2603
16th to endNight
21%14%8%8%6%34445%19%
2778

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
17%14%6%8%8%46%5%5%5%17%
1432
16th to endDay
15%17%8%10%8%5%5%34415%
1584
February1st to 15thDay
12%16%5%11%7%46%5%46%20%
1601
16th to endDay
12%12%6%8%8%46%45%5%24%
1580
March1st to 15thDay
15%10%38%7%44447%29%
1867
16th to endDay
16%8%5%7%8%44445%30%
2111
April1st to 15thDay
20%10%45%43435%6%31%
2166
16th to endDay
16%6%36%5%34446%37%
2340
May1st to 15thDay
19%7%345%24447%36%
2331
16th to endDay
11%5%36%5%35%45%7%41%
2495
June1st to 15thDay
11%6%25%5%3446%7%40%
2646
16th to endDay
10%426%5%36%5%8%10%37%
2627
July1st to 15thDay
6%3245%35%5%7%9%46%
2520
16th to endDay
8%325%5%36%5%6%9%42%
2612
August1st to 15thDay
9%5%15%5%35%7%5%9%40%
2340
16th to endDay
10%5%25%435%46%7%43%
2455
September1st to 15thDay
12%425%425%5%5%8%42%
2037
16th to endDay
12%5%25%5%25%45%9%41%
1829
October1st to 15thDay
15%7%25%6%35%345%38%
1738
16th to endDay
22%9%46%5%35%346%27%
1639
November1st to 15thDay
15%10%26%6%25%446%35%
1582
16th to endDay
16%12%48%6%36%447%24%
1548
December1st to 15thDay
16%14%6%10%7%35%44422%
1356
16th to endDay
19%15%8%9%7%3345%6%16%
1442
January1st to 15thNight
21%12%5%9%7%34335%22%
2506
16th to endNight
14%12%8%9%7%45%5%5%5%20%
2640
February1st to 15thNight
13%14%5%10%6%35%445%26%
2249
16th to endNight
15%12%410%7%34445%26%
1893
March1st to 15thNight
16%9%46%5%23445%35%
2092
16th to endNight
15%8%46%42435%7%36%
2112
April1st to 15thNight
20%8%46%313447%34%
1790
16th to endNight
17%6%24424346%41%
1620
May1st to 15thNight
15%6%36%5%25%447%36%
1619
16th to endNight
12%3245%35%5%5%7%43%
1616
June1st to 15thNight
10%5%25%4345%6%7%43%
1311
16th to endNight
8%4245%25%6%5%9%44%
1327
July1st to 15thNight
6%32442445%7%53%
1440
16th to endNight
6%3244345%6%9%50%
1555
August1st to 15thNight
7%3135%246%6%8%49%
1620
16th to endNight
9%414323446%52%
1746
September1st to 15thNight
10%424324446%51%
1911
16th to endNight
11%5%2442435%6%49%
1837
October1st to 15thNight
16%6%35%42435%5%41%
1890
16th to endNight
21%8%37%6%44445%30%
2230
November1st to 15thNight
14%8%35%5%34446%37%
2276
16th to endNight
21%11%46%6%3445%6%25%
2409
December1st to 15thNight
18%15%7%8%6%33445%22%
2603
16th to endNight
21%13%8%8%6%34445%19%
2778

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
65%7%10%12%3
1433
16th to endDay
71%47%10%5%
1584
February1st to 15thDay
63%5%11%15%4
1603
16th to endDay
59%5%11%16%6%
1580
March1st to 15thDay
54%5%11%20%7%
1867
16th to endDay
54%413%19%6%1
2112
April1st to 15thDay
53%410%21%10%
2166
16th to endDay
46%414%18%13%1
2340
May1st to 15thDay
46%5%12%22%10%2
2331
16th to endDay
41%6%12%25%14%
2499
June1st to 15thDay
40%5%13%25%14%
2646
16th to endDay
38%7%14%22%16%
2627
July1st to 15thDay
30%7%11%28%18%2
2371
16th to endDay
36%6%14%23%15%2
2448
August1st to 15thDay
38%6%13%26%13%1
2327
16th to endDay
37%6%11%27%14%2
2455
September1st to 15thDay
38%6%13%28%11%1
2037
16th to endDay
39%413%28%12%
1829
October1st to 15thDay
47%411%23%12%
1738
16th to endDay
58%414%16%4
1639
November1st to 15thDay
49%5%12%22%9%
1582
16th to endDay
58%413%16%5%1
1548
December1st to 15thDay
63%5%13%13%3
1356
16th to endDay
67%412%11%2
1442
January1st to 15thNight
65%310%13%7%
2506
16th to endNight
62%5%13%13%3
2640
February1st to 15thNight
59%5%8%18%6%
2258
16th to endNight
59%311%17%8%
1893
March1st to 15thNight
51%411%21%10%1
2092
16th to endNight
47%5%11%21%12%1
2112
April1st to 15thNight
49%310%20%15%
1790
16th to endNight
43%410%21%17%3
1620
May1st to 15thNight
47%410%21%12%3
1620
16th to endNight
38%5%11%24%15%4
1618
June1st to 15thNight
37%414%24%18%1
1311
16th to endNight
33%7%14%25%18%1
1327
July1st to 15thNight
28%410%31%22%2
1360
16th to endNight
29%6%16%25%20%1
1456
August1st to 15thNight
29%7%11%33%16%1
1609
16th to endNight
30%5%13%29%18%1
1746
September1st to 15thNight
33%5%11%29%19%
1911
16th to endNight
34%5%13%31%14%
1837
October1st to 15thNight
42%5%10%25%14%
1890
16th to endNight
55%412%20%6%
2230
November1st to 15thNight
46%5%12%22%11%
2276
16th to endNight
57%5%13%17%5%
2409
December1st to 15thNight
63%312%13%5%
2603
16th to endNight
66%5%11%12%4
2778

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
25%7%43%17%5%
90
16th to endDay
31%13%29%22%21
96
February1st to 15thDay
24%18%41%14%1
90
16th to endDay
16%12%34%27%9%
81
March1st to 15thDay
31%8%22%29%7%
157
16th to endDay
25%427%26%12%2
288
April1st to 15thDay
25%9%28%25%9%2
270
16th to endDay
19%8%29%22%12%7%
270
May1st to 15thDay
24%7%27%19%14%7%
288
16th to endDay
16%10%23%23%16%8%
395
June1st to 15thDay
13%7%27%31%12%7%
495
16th to endDay
12%6%29%26%18%6%
495
July1st to 15thDay
9%323%30%20%12%
475
16th to endDay
9%223%30%23%10%
472
August1st to 15thDay
10%115%25%27%20%
313
16th to endDay
15%413%21%26%18%
332
September1st to 15thDay
9%318%23%28%15%
315
16th to endDay
16%216%25%25%14%
259
October1st to 15thDay
19%5%26%27%18%3
255
16th to endDay
27%5%32%28%5%
151
November1st to 15thDay
8%13%30%28%14%4
90
16th to endDay
21%17%33%15%11%
78
December1st to 15thDay
28%15%36%20%
60
16th to endDay
28%17%39%14%
81
January1st to 15thNight
26%9%34%21%6%
900
16th to endNight
20%8%32%31%7%
912
February1st to 15thNight
21%10%35%26%5%
704
16th to endNight
22%9%29%31%6%
631
March1st to 15thNight
21%8%30%32%7%
720
16th to endNight
18%8%28%32%9%1
768
April1st to 15thNight
23%9%31%27%6%
563
16th to endNight
22%430%29%10%1
540
May1st to 15thNight
19%431%34%9%1
540
16th to endNight
14%425%35%16%2
563
June1st to 15thNight
12%327%41%14%
411
16th to endNight
9%221%42%22%
427
July1st to 15thNight
10%16%44%25%2
510
16th to endNight
8%117%44%26%2
564
August1st to 15thNight
8%113%44%29%2
539
16th to endNight
12%117%33%30%4
573
September1st to 15thNight
12%318%34%24%6%
651
16th to endNight
14%416%34%26%4
665
October1st to 15thNight
19%6%21%33%16%1
660
16th to endNight
25%9%30%27%6%
704
November1st to 15thNight
20%9%29%28%12%
700
16th to endNight
26%9%30%25%7%
720
December1st to 15thNight
28%9%32%25%3
803
16th to endNight
29%8%34%23%4
960
Page generated at 2017-09-18 08:38:29. Version ac04

Copyright 2017 A. Danko


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