Torch Lake Township
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Torch Lake Township 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
29%
15814
11%
46886
7%
15772
33%
15772
14%
35461

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
10%
900
2%
2506
1%
895
11%
895
4%
2277
January16th to endNight
12%
960
4%
2688
2%
960
14%
960
4%
2413
February1st to 15thNight
16%
756
4%
2293
2%
756
19%
756
6%
1985
February16th to endNight
23%
631
8%
1893
4%
631
26%
631
8%
1574
March1st to 15thNight
27%
720
14%
2134
7%
720
33%
720
16%
1555
March16th to endNight
31%
729
19%
2073
11%
729
38%
729
19%
1450
April1st to 15thNight
25%
539
13%
1790
8%
539
32%
539
14%
1266
April16th to endNight
31%
540
19%
1620
8%
540
40%
540
19%
1082
May1st to 15thNight
32%
540
14%
1620
8%
540
39%
540
18%
1113
May16th to endNight
41%
562
15%
1498
8%
561
48%
561
26%
969
June1st to 15thNight
37%
402
13%
1302
8%
402
43%
402
19%
846
June16th to endNight
46%
408
13%
1308
8%
408
51%
408
23%
806
July1st to 15thNight
54%
510
14%
1360
9%
510
58%
510
34%
812
July16th to endNight
47%
564
16%
1417
9%
531
54%
531
32%
859
August1st to 15thNight
59%
539
19%
1554
16%
536
63%
536
33%
893
August16th to endNight
53%
573
17%
1780
12%
573
57%
573
26%
1101
September1st to 15thNight
50%
606
16%
1866
12%
606
54%
606
27%
1180
September16th to endNight
48%
661
17%
1826
13%
661
51%
661
28%
1208
October1st to 15thNight
33%
660
16%
1875
11%
660
38%
660
18%
1368
October16th to endNight
21%
704
8%
2288
5%
704
26%
704
9%
1832
November1st to 15thNight
23%
700
14%
2276
11%
700
28%
700
12%
1728
November16th to endNight
15%
750
6%
2431
5%
750
17%
750
5%
2105
December1st to 15thNight
8%
900
1%
2700
1%
900
8%
900
3%
2493
December16th to endNight
11%
960
3%
2788
1%
960
13%
960
4%
2546

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
15%10%47%5%34446%32%
47871
Night
16%12%5%9%6%34345%27%
47054
Cloud CoverDay
15%10%47%5%24446%32%
47880
Night
16%12%5%9%6%34345%28%
47059
TransparencyDay
51%411%20%9%
47557
Night
59%410%17%8%
46886
SeeingDay
17%14%23%25%14%4
6005
Night
19%21%22%24%10%1
15818

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
18%16%13%14%10%433326%
1432
16th to endDay
13%18%11%17%12%35%3338%
1536
February1st to 15thDay
13%15%8%14%14%34345%12%
1564
16th to endDay
13%16%8%12%9%45%5%35%16%
1580
March1st to 15thDay
12%9%5%8%8%45%446%29%
1815
16th to endDay
15%7%47%5%3435%7%34%
2163
April1st to 15thDay
20%11%34423446%33%
2157
16th to endDay
16%11%35%42445%6%36%
2340
May1st to 15thDay
15%6%36%5%3445%5%38%
2331
16th to endDay
11%6%244245%5%8%44%
2615
June1st to 15thDay
14%425%43446%8%41%
2655
16th to endDay
13%5%25%4245%5%9%41%
2646
July1st to 15thDay
10%32332446%8%49%
2520
16th to endDay
9%41442446%10%47%
2655
August1st to 15thDay
8%4245%3445%9%46%
2397
16th to endDay
14%5%24423447%45%
2420
September1st to 15thDay
15%5%2343345%6%43%
2082
16th to endDay
17%424425%5%47%39%
1824
October1st to 15thDay
23%8%36%6%23347%29%
1755
16th to endDay
28%14%47%6%345%45%15%
1584
November1st to 15thDay
17%16%6%7%433346%25%
1582
16th to endDay
21%25%9%11%5%2323312%
1527
December1st to 15thDay
20%22%13%17%8%222117%
1260
16th to endDay
20%24%11%14%7%232237%
1431
January1st to 15thNight
18%17%10%16%13%322239%
2506
16th to endNight
14%17%8%15%13%3423310%
2688
February1st to 15thNight
12%17%9%14%12%4432412%
2291
16th to endNight
15%14%7%14%9%45%24417%
1893
March1st to 15thNight
13%10%49%6%24345%33%
2121
16th to endNight
14%8%48%5%2445%5%35%
2073
April1st to 15thNight
21%10%35%6%24445%30%
1790
16th to endNight
17%8%345%23436%39%
1620
May1st to 15thNight
14%7%36%5%46%45%9%32%
1620
16th to endNight
12%5%25%5%245%5%6%43%
1496
June1st to 15thNight
13%5%25%6%34446%41%
1302
16th to endNight
11%6%245%245%5%9%41%
1308
July1st to 15thNight
9%424425%5%5%7%49%
1440
16th to endNight
7%425%5%1346%7%49%
1513
August1st to 15thNight
7%41443436%9%49%
1563
16th to endNight
13%5%1443435%6%47%
1780
September1st to 15thNight
15%5%26%424346%45%
1866
16th to endNight
18%5%25%42345%7%39%
1826
October1st to 15thNight
23%9%36%5%32245%32%
1875
16th to endNight
27%14%47%6%3443419%
2288
November1st to 15thNight
20%16%5%6%5%23345%26%
2276
16th to endNight
22%24%8%10%5%3332312%
2431
December1st to 15thNight
19%25%13%15%6%221117%
2700
16th to endNight
19%21%11%14%7%342337%
2788

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%18%12%13%11%444337%
1432
16th to endDay
13%17%11%19%10%443329%
1536
February1st to 15thDay
13%15%8%14%13%3434413%
1564
16th to endDay
13%16%8%12%8%35%435%18%
1580
March1st to 15thDay
12%10%48%8%3445%6%28%
1825
16th to endDay
15%9%5%7%5%24347%33%
2162
April1st to 15thDay
20%12%3442435%5%33%
2157
16th to endDay
17%10%36%423446%36%
2340
May1st to 15thDay
16%7%35%5%345%5%5%38%
2331
16th to endDay
12%5%244245%5%8%44%
2615
June1st to 15thDay
14%5%245%245%6%9%40%
2655
16th to endDay
14%5%24425%46%8%40%
2646
July1st to 15thDay
10%41342446%8%49%
2520
16th to endDay
9%4233245%5%9%48%
2655
August1st to 15thDay
8%4144445%6%8%46%
2397
16th to endDay
15%5%24424446%44%
2420
September1st to 15thDay
15%5%245%24347%43%
2082
16th to endDay
17%4344245%5%7%39%
1824
October1st to 15thDay
23%9%46%5%24236%30%
1755
16th to endDay
28%15%5%7%6%34346%14%
1584
November1st to 15thDay
18%17%5%7%423346%24%
1582
16th to endDay
19%26%8%11%5%2323411%
1527
December1st to 15thDay
19%22%13%18%7%212227%
1260
16th to endDay
20%24%11%14%8%222237%
1431
January1st to 15thNight
18%16%9%17%12%332229%
2506
16th to endNight
14%18%8%15%12%3423411%
2688
February1st to 15thNight
12%17%9%13%12%4433314%
2284
16th to endNight
15%16%6%13%9%35%33418%
1893
March1st to 15thNight
13%10%5%9%6%2444433%
2134
16th to endNight
14%9%46%6%3445%6%36%
2073
April1st to 15thNight
21%10%36%5%2444431%
1790
16th to endNight
16%9%36%423436%39%
1620
May1st to 15thNight
15%7%35%6%45%5%5%8%33%
1619
16th to endNight
12%5%25%5%2445%7%43%
1496
June1st to 15thNight
13%6%345%25%447%41%
1302
16th to endNight
11%6%34425%46%8%42%
1308
July1st to 15thNight
10%424425%5%5%7%48%
1440
16th to endNight
7%5%244235%48%49%
1513
August1st to 15thNight
7%3144345%6%8%50%
1563
16th to endNight
14%41443345%7%46%
1780
September1st to 15thNight
15%6%24423346%45%
1866
16th to endNight
18%5%25%424347%39%
1826
October1st to 15thNight
23%9%35%5%32336%33%
1875
16th to endNight
26%13%47%7%3443419%
2288
November1st to 15thNight
19%17%5%7%423346%25%
2276
16th to endNight
21%23%7%11%5%2433312%
2431
December1st to 15thNight
19%25%14%15%6%221228%
2700
16th to endNight
19%20%13%13%7%343337%
2788

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
84%35%5%
1433
16th to endDay
82%35%6%1
1536
February1st to 15thDay
74%49%9%1
1566
16th to endDay
69%49%12%3
1580
March1st to 15thDay
55%6%12%17%6%1
1825
16th to endDay
49%413%23%7%1
2163
April1st to 15thDay
51%310%22%11%
2157
16th to endDay
48%311%17%15%2
2340
May1st to 15thDay
46%49%24%11%3
2331
16th to endDay
37%5%11%27%15%2
2619
June1st to 15thDay
39%5%13%27%13%1
2655
16th to endDay
37%7%16%25%13%1
2646
July1st to 15thDay
30%5%12%32%18%1
2371
16th to endDay
30%6%15%28%17%1
2488
August1st to 15thDay
32%5%15%32%12%
2382
16th to endDay
38%5%12%27%14%1
2420
September1st to 15thDay
40%412%28%12%
2082
16th to endDay
40%5%16%25%11%
1824
October1st to 15thDay
55%49%22%7%
1755
16th to endDay
69%5%13%9%2
1584
November1st to 15thDay
60%312%16%6%
1582
16th to endDay
77%310%6%1
1527
December1st to 15thDay
87%15%4
1260
16th to endDay
83%28%41
1431
January1st to 15thNight
83%27%5%1
2506
16th to endNight
79%48%6%1
2688
February1st to 15thNight
75%46%10%2
2293
16th to endNight
71%310%11%3
1893
March1st to 15thNight
54%411%20%8%
2134
16th to endNight
49%311%22%11%
2073
April1st to 15thNight
54%47%20%11%1
1790
16th to endNight
46%311%20%16%2
1620
May1st to 15thNight
48%410%21%11%3
1620
16th to endNight
38%5%12%27%13%2
1498
June1st to 15thNight
44%410%22%16%
1302
16th to endNight
37%6%15%25%14%
1308
July1st to 15thNight
31%413%28%19%2
1360
16th to endNight
32%5%15%28%16%1
1417
August1st to 15thNight
30%5%17%33%12%
1554
16th to endNight
38%5%14%25%15%1
1780
September1st to 15thNight
40%412%25%16%
1866
16th to endNight
41%415%28%8%
1826
October1st to 15thNight
54%39%21%9%
1875
16th to endNight
67%311%13%4
2288
November1st to 15thNight
60%411%15%6%
2276
16th to endNight
77%210%6%1
2431
December1st to 15thNight
86%25%5%
2700
16th to endNight
83%37%41
2788

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
21%14%32%27%4
90
16th to endDay
32%8%22%29%6%1
96
February1st to 15thDay
21%17%34%22%4
90
16th to endDay
19%11%39%25%3
81
March1st to 15thDay
17%17%26%24%12%1
115
16th to endDay
23%16%22%25%11%1
288
April1st to 15thDay
22%19%22%23%10%1
270
16th to endDay
22%18%25%17%13%2
270
May1st to 15thDay
17%18%25%22%11%4
288
16th to endDay
13%18%28%23%12%3
515
June1st to 15thDay
15%16%27%23%14%1
495
16th to endDay
14%15%23%26%15%3
495
July1st to 15thDay
10%13%22%27%18%7%
475
16th to endDay
9%15%22%30%17%5%
515
August1st to 15thDay
8%8%15%34%24%9%
370
16th to endDay
20%7%15%28%18%9%
332
September1st to 15thDay
16%6%19%22%19%15%
315
16th to endDay
17%10%15%29%21%6%
257
October1st to 15thDay
26%12%23%24%9%3
244
16th to endDay
25%16%32%21%31
96
November1st to 15thDay
21%7%30%28%10%2
90
16th to endDay
27%18%26%18%7%
79
December1st to 15thDay
40%16%28%11%11
60
16th to endDay
39%17%37%31
79
January1st to 15thNight
20%27%26%19%5%
900
16th to endNight
18%27%27%19%5%
960
February1st to 15thNight
17%25%27%22%5%
759
16th to endNight
19%23%23%26%7%
631
March1st to 15thNight
14%24%25%23%10%
720
16th to endNight
17%21%22%28%8%
729
April1st to 15thNight
21%22%25%23%6%
539
16th to endNight
19%22%22%25%9%
540
May1st to 15thNight
14%18%27%28%10%
540
16th to endNight
12%20%20%32%13%
563
June1st to 15thNight
14%19%20%33%11%
402
16th to endNight
10%20%16%34%17%1
408
July1st to 15thNight
11%13%14%33%23%3
510
16th to endNight
10%17%17%31%20%2
564
August1st to 15thNight
9%10%11%38%27%2
539
16th to endNight
15%10%15%32%23%1
573
September1st to 15thNight
17%10%18%28%20%5%
606
16th to endNight
18%11%16%29%18%4
661
October1st to 15thNight
26%14%20%24%12%
660
16th to endNight
32%18%20%21%5%
704
November1st to 15thNight
25%23%23%21%6%
700
16th to endNight
29%26%21%17%4
750
December1st to 15thNight
26%31%27%13%1
900
16th to endNight
23%25%27%18%31
960
Page generated at 2017-09-17 12:05:46. Version ac04

Copyright 2017 A. Danko


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