Livonia
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Livonia clear sky chart from 2005-11-05 to

2017-09-12
.

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
36%
15708
15%
46876
10%
15668
42%
15668
20%
32496

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
16%
898
9%
2506
4%
895
21%
895
12%
1981
January16th to endNight
19%
835
9%
2563
4%
835
24%
835
10%
2029
February1st to 15thNight
18%
701
9%
2263
3%
701
25%
701
10%
1755
February16th to endNight
23%
631
14%
1893
6%
631
31%
631
15%
1388
March1st to 15thNight
26%
720
15%
2071
8%
720
32%
720
17%
1508
March16th to endNight
32%
768
18%
2112
10%
768
39%
768
21%
1494
April1st to 15thNight
29%
596
14%
1815
7%
596
36%
596
19%
1257
April16th to endNight
34%
540
19%
1620
7%
540
44%
540
23%
1072
May1st to 15thNight
37%
540
14%
1620
8%
540
43%
540
21%
1115
May16th to endNight
47%
562
15%
1684
10%
561
54%
561
28%
1071
June1st to 15thNight
50%
465
16%
1380
12%
465
57%
465
30%
862
June16th to endNight
53%
490
18%
1390
14%
490
59%
490
33%
879
July1st to 15thNight
61%
510
17%
1360
13%
510
64%
510
40%
820
July16th to endNight
65%
564
19%
1518
15%
531
70%
531
39%
879
August1st to 15thNight
63%
539
20%
1609
15%
536
67%
536
36%
962
August16th to endNight
64%
573
24%
1732
18%
573
69%
573
35%
1007
September1st to 15thNight
59%
661
24%
1898
19%
661
63%
661
35%
1117
September16th to endNight
57%
657
24%
1815
18%
657
61%
657
33%
1132
October1st to 15thNight
46%
660
21%
1900
17%
660
51%
660
27%
1221
October16th to endNight
25%
704
15%
2195
9%
704
34%
704
17%
1531
November1st to 15thNight
36%
700
20%
2276
16%
700
44%
700
23%
1454
November16th to endNight
25%
720
14%
2391
9%
720
31%
720
14%
1725
December1st to 15thNight
18%
720
8%
2520
4%
720
23%
720
9%
1945
December16th to endNight
13%
954
7%
2745
2%
954
18%
954
9%
2292

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%8%36%6%35%45%7%32%
47751
Night
15%8%46%5%3445%6%36%
47056
Cloud CoverDay
14%8%36%6%35%45%7%32%
47761
Night
15%8%46%5%3445%6%35%
47060
TransparencyDay
49%6%11%19%11%1
47449
Night
48%5%11%21%11%1
46876
SeeingDay
16%9%28%23%14%6%
5790
Night
19%9%28%29%12%1
15714

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
19%14%6%9%8%45%45%6%16%
1432
16th to endDay
15%17%7%10%8%46%445%15%
1659
February1st to 15thDay
15%15%5%10%8%5%5%5%5%5%19%
1597
16th to endDay
14%14%5%11%7%35%447%20%
1580
March1st to 15thDay
17%11%5%8%7%24446%27%
1877
16th to endDay
17%9%5%7%7%34445%28%
2112
April1st to 15thDay
19%10%45%435%446%31%
2142
16th to endDay
17%8%35%5%24446%37%
2340
May1st to 15thDay
19%8%35%5%45%446%31%
2331
16th to endDay
13%5%35%5%3445%7%40%
2431
June1st to 15thDay
11%5%26%5%35%45%8%39%
2567
16th to endDay
10%5%25%6%46%6%9%10%33%
2560
July1st to 15thDay
7%425%5%45%5%5%8%44%
2520
16th to endDay
9%4246%36%5%7%10%38%
2545
August1st to 15thDay
8%5%26%7%36%6%7%8%37%
2340
16th to endDay
10%425%6%35%5%7%9%38%
2468
September1st to 15thDay
11%6%345%45%6%5%8%39%
1969
16th to endDay
12%5%25%5%345%6%9%39%
1815
October1st to 15thDay
15%7%245%2445%7%38%
1730
16th to endDay
21%8%36%5%34345%32%
1675
November1st to 15thDay
14%7%35%6%3445%6%38%
1582
16th to endDay
18%12%46%6%25%45%5%28%
1566
December1st to 15thDay
17%11%7%10%7%35%35%5%21%
1440
16th to endDay
22%15%8%11%6%33346%14%
1473
January1st to 15thNight
21%13%5%7%6%3435%5%23%
2506
16th to endNight
14%14%7%10%8%45%445%21%
2563
February1st to 15thNight
15%13%5%9%7%25%44425%
2261
16th to endNight
17%10%5%7%6%35%345%29%
1893
March1st to 15thNight
17%10%36%5%2445%5%32%
2059
16th to endNight
15%7%36%5%35%45%7%35%
2112
April1st to 15thNight
17%9%445%3445%7%33%
1815
16th to endNight
15%6%26%4245%6%6%39%
1620
May1st to 15thNight
18%6%35%5%25%447%35%
1620
16th to endNight
12%5%345%34447%44%
1682
June1st to 15thNight
9%4245%25%46%8%46%
1380
16th to endNight
8%314435%5%6%9%45%
1390
July1st to 15thNight
7%3243245%5%7%53%
1440
16th to endNight
44244246%5%9%52%
1623
August1st to 15thNight
4425%5%35%5%5%9%49%
1620
16th to endNight
10%423324347%52%
1732
September1st to 15thNight
11%4233245%47%51%
1898
16th to endNight
12%43442345%7%48%
1815
October1st to 15thNight
15%6%3432445%6%43%
1900
16th to endNight
21%7%25%5%34445%34%
2195
November1st to 15thNight
15%6%345%25%5%46%40%
2276
16th to endNight
22%11%46%424346%29%
2391
December1st to 15thNight
20%13%6%8%5%25%44423%
2520
16th to endNight
23%14%6%9%6%34445%16%
2745

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
19%14%5%9%8%46%5%5%5%16%
1432
16th to endDay
15%17%8%9%9%36%45%415%
1659
February1st to 15thDay
15%15%5%10%8%45%5%45%19%
1597
16th to endDay
14%13%5%11%7%36%447%21%
1580
March1st to 15thDay
18%10%5%9%6%34346%27%
1888
16th to endDay
17%10%47%7%43446%28%
2111
April1st to 15thDay
19%10%45%5%25%447%30%
2142
16th to endDay
17%8%26%5%24346%38%
2340
May1st to 15thDay
19%9%36%5%35%447%31%
2331
16th to endDay
13%5%26%5%25%45%7%40%
2431
June1st to 15thDay
10%5%25%6%36%5%5%8%39%
2567
16th to endDay
10%5%35%6%46%6%8%10%33%
2560
July1st to 15thDay
7%425%5%36%5%5%8%44%
2520
16th to endDay
8%4346%26%6%7%10%38%
2545
August1st to 15thDay
8%5%26%6%35%7%7%8%37%
2340
16th to endDay
11%4246%36%5%7%9%38%
2468
September1st to 15thDay
12%6%245%35%5%5%8%39%
1969
16th to endDay
12%5%26%5%35%5%6%10%38%
1815
October1st to 15thDay
14%7%25%5%2445%7%38%
1730
16th to endDay
20%8%36%5%34346%32%
1675
November1st to 15thDay
14%7%26%5%35%45%7%38%
1582
16th to endDay
17%12%47%6%3445%6%27%
1566
December1st to 15thDay
17%11%8%10%8%3445%5%21%
1440
16th to endDay
21%15%8%11%6%33445%13%
1473
January1st to 15thNight
21%13%48%6%3345%5%22%
2506
16th to endNight
14%14%7%10%8%445%45%21%
2563
February1st to 15thNight
15%13%5%9%7%35%445%25%
2254
16th to endNight
17%9%6%7%7%35%345%29%
1893
March1st to 15thNight
18%9%47%5%25%45%5%31%
2071
16th to endNight
16%6%36%5%35%447%36%
2112
April1st to 15thNight
18%8%35%5%3445%7%33%
1815
16th to endNight
15%6%35%425%5%6%6%39%
1620
May1st to 15thNight
18%6%35%5%25%45%6%36%
1619
16th to endNight
12%5%35%434448%44%
1682
June1st to 15thNight
9%424426%35%9%46%
1380
16th to endNight
8%325%43446%9%45%
1390
July1st to 15thNight
6%41442445%8%53%
1440
16th to endNight
43243246%5%8%53%
1623
August1st to 15thNight
4424435%5%6%9%48%
1620
16th to endNight
10%423334348%51%
1732
September1st to 15thNight
10%4133245%47%51%
1898
16th to endNight
12%425%423447%47%
1815
October1st to 15thNight
15%5%35%33345%7%42%
1900
16th to endNight
20%7%26%5%3445%5%34%
2195
November1st to 15thNight
14%7%34435%5%5%6%40%
2276
16th to endNight
22%10%46%42435%6%29%
2391
December1st to 15thNight
20%12%5%8%5%35%445%23%
2520
16th to endNight
22%14%6%10%6%24445%16%
2745

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
67%6%12%9%4
1433
16th to endDay
70%6%9%8%4
1659
February1st to 15thDay
65%5%9%13%5%
1599
16th to endDay
63%5%10%15%5%
1580
March1st to 15thDay
59%5%11%16%5%1
1888
16th to endDay
56%410%20%6%
2112
April1st to 15thDay
53%5%10%18%11%
2142
16th to endDay
47%413%16%14%2
2340
May1st to 15thDay
53%5%9%18%10%2
2331
16th to endDay
42%6%12%24%12%2
2435
June1st to 15thDay
41%6%11%23%14%1
2567
16th to endDay
41%8%13%18%15%1
2560
July1st to 15thDay
36%6%10%24%19%2
2371
16th to endDay
37%7%14%21%15%2
2387
August1st to 15thDay
39%7%13%24%13%1
2327
16th to endDay
38%8%11%23%15%2
2468
September1st to 15thDay
40%7%12%25%13%
1969
16th to endDay
38%7%11%29%12%
1815
October1st to 15thDay
43%412%24%12%1
1730
16th to endDay
53%5%13%18%8%
1675
November1st to 15thDay
44%5%12%22%12%1
1582
16th to endDay
56%5%12%19%5%
1566
December1st to 15thDay
64%413%12%4
1440
16th to endDay
72%5%11%7%3
1473
January1st to 15thNight
62%412%13%6%
2506
16th to endNight
65%412%12%4
2563
February1st to 15thNight
61%5%10%14%6%
2263
16th to endNight
56%412%18%7%
1893
March1st to 15thNight
53%5%10%18%10%1
2071
16th to endNight
48%5%11%22%10%1
2112
April1st to 15thNight
49%410%20%14%
1815
16th to endNight
43%5%11%18%17%3
1620
May1st to 15thNight
46%6%10%20%12%2
1620
16th to endNight
39%6%11%23%15%3
1684
June1st to 15thNight
36%6%12%27%15%1
1380
16th to endNight
33%7%12%25%19%1
1390
July1st to 15thNight
29%6%10%30%21%2
1360
16th to endNight
26%8%15%25%20%3
1518
August1st to 15thNight
30%7%12%31%15%2
1609
16th to endNight
32%412%28%18%3
1732
September1st to 15thNight
31%6%11%29%20%1
1898
16th to endNight
35%5%10%31%16%
1815
October1st to 15thNight
40%5%11%23%18%1
1900
16th to endNight
50%413%22%7%
2195
November1st to 15thNight
42%5%12%24%13%1
2276
16th to endNight
55%412%20%6%
2391
December1st to 15thNight
62%5%12%13%5%
2520
16th to endNight
69%411%10%4
2745

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%21%30%21%41
90
16th to endDay
29%15%39%12%3
96
February1st to 15thDay
24%18%43%12%1
90
16th to endDay
19%18%39%17%4
81
March1st to 15thDay
32%14%25%19%8%
178
16th to endDay
22%10%34%20%9%2
288
April1st to 15thDay
22%11%31%23%8%1
270
16th to endDay
24%11%31%14%10%7%
270
May1st to 15thDay
25%10%30%19%8%5%
288
16th to endDay
16%9%28%22%15%7%
331
June1st to 15thDay
11%7%35%28%14%2
477
16th to endDay
13%9%32%26%12%5%
495
July1st to 15thDay
9%5%29%29%17%7%
475
16th to endDay
9%424%26%22%11%
405
August1st to 15thDay
9%123%28%17%19%
313
16th to endDay
12%5%16%25%22%17%
332
September1st to 15thDay
11%5%20%22%25%14%
299
16th to endDay
15%318%23%27%10%
254
October1st to 15thDay
18%7%21%25%20%7%
255
16th to endDay
27%10%34%20%5%1
187
November1st to 15thDay
8%16%30%30%13%1
90
16th to endDay
24%24%27%16%7%
81
December1st to 15thDay
23%21%36%13%5%
60
16th to endDay
31%29%28%10%
85
January1st to 15thNight
26%15%33%18%4
900
16th to endNight
21%12%34%26%5%
835
February1st to 15thNight
24%12%35%23%3
704
16th to endNight
22%12%32%27%4
631
March1st to 15thNight
22%12%31%27%6%
720
16th to endNight
18%11%30%28%9%1
768
April1st to 15thNight
21%13%30%28%5%
596
16th to endNight
18%9%33%28%8%1
540
May1st to 15thNight
20%7%27%32%10%1
540
16th to endNight
13%426%35%17%2
563
June1st to 15thNight
9%328%46%12%
465
16th to endNight
9%227%40%18%1
490
July1st to 15thNight
10%120%40%23%3
510
16th to endNight
5%220%46%21%3
564
August1st to 15thNight
7%119%40%27%4
539
16th to endNight
13%114%34%33%2
573
September1st to 15thNight
13%5%18%31%27%4
661
16th to endNight
13%5%18%31%26%4
657
October1st to 15thNight
18%8%23%28%19%2
660
16th to endNight
24%11%32%25%5%
704
November1st to 15thNight
18%9%31%26%12%1
700
16th to endNight
27%15%27%20%8%
720
December1st to 15thNight
28%13%33%18%5%
720
16th to endNight
30%11%34%19%3
954
Page generated at 2017-09-13 07:39:09. Version ac04

Copyright 2017 A. Danko


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