Canton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Canton clear sky chart from 2005-11-05 to 2017-09-19.

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
46%
15473
23%
46961
15%
15430
55%
15430
27%
29133

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
24%
720
23%
2327
9%
716
40%
716
20%
1469
January16th to endNight
25%
768
24%
2442
11%
768
41%
768
21%
1558
February1st to 15thNight
27%
704
25%
2112
10%
701
42%
701
25%
1302
February16th to endNight
23%
631
24%
1893
8%
631
37%
631
23%
1198
March1st to 15thNight
28%
720
22%
2073
10%
720
39%
720
25%
1336
March16th to endNight
37%
768
21%
2112
12%
768
44%
768
29%
1336
April1st to 15thNight
41%
617
25%
1875
15%
617
51%
617
32%
1078
April16th to endNight
48%
540
26%
1709
18%
540
57%
540
32%
983
May1st to 15thNight
49%
540
20%
1620
12%
540
57%
540
28%
1017
May16th to endNight
62%
561
20%
1682
14%
561
66%
561
31%
1025
June1st to 15thNight
71%
540
16%
1620
14%
540
72%
540
29%
1039
June16th to endNight
75%
540
17%
1620
15%
540
76%
540
34%
969
July1st to 15thNight
70%
510
14%
1530
12%
510
70%
510
27%
1003
July16th to endNight
71%
564
16%
1595
15%
531
73%
531
28%
1030
August1st to 15thNight
72%
539
19%
1648
20%
536
72%
536
28%
1035
August16th to endNight
64%
573
19%
1910
21%
573
65%
573
22%
1275
September1st to 15thNight
62%
693
18%
1953
17%
693
63%
693
28%
1310
September16th to endNight
56%
673
25%
1858
17%
673
62%
673
31%
1188
October1st to 15thNight
53%
660
34%
1815
24%
660
60%
660
39%
1055
October16th to endNight
50%
704
33%
2115
25%
704
62%
704
36%
1181
November1st to 15thNight
48%
700
30%
2276
24%
700
59%
700
34%
1221
November16th to endNight
38%
720
27%
2340
17%
720
52%
720
27%
1371
December1st to 15thNight
31%
720
22%
2340
13%
720
43%
720
23%
1461
December16th to endNight
29%
768
19%
2496
13%
768
38%
768
18%
1693

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%5%245%35%5%5%7%40%
47846
Night
12%5%2442445%7%45%
47160
TransparencyDay
40%6%12%19%17%4
47547
Night
37%6%11%20%19%5%
46963
SeeingDay
16%7%19%22%21%12%
5354
Night
14%8%23%27%21%3
15475

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 15thDay
19%6%25%31435%5%41%
1611
16th to endDay
18%6%24424345%43%
1779
February1st to 15thDay
17%6%24324447%41%
1750
16th to endDay
20%5%15%324335%41%
1580
March1st to 15thDay
17%6%15%5%2345%7%39%
1885
16th to endDay
17%5%24434446%42%
2111
April1st to 15thDay
13%6%244335%5%6%44%
2082
16th to endDay
13%3244345%47%47%
2250
May1st to 15thDay
12%5%25%43446%7%42%
2331
16th to endDay
10%425%6%35%6%6%8%40%
2431
June1st to 15thDay
9%5%25%6%36%7%8%11%33%
2340
16th to endDay
6%313447%7%8%10%42%
2340
July1st to 15thDay
11%425%7%48%6%8%9%30%
2340
16th to endDay
8%5%25%7%5%8%8%7%9%30%
2465
August1st to 15thDay
9%5%25%5%47%7%8%9%33%
2298
16th to endDay
13%6%26%8%5%7%7%8%8%26%
2292
September1st to 15thDay
13%5%25%5%35%6%5%8%37%
1993
16th to endDay
16%5%2343445%7%42%
1848
October1st to 15thDay
13%414323335%54%
1815
16th to endDay
13%32331323457%
1755
November1st to 15thDay
14%32321434455%
1582
16th to endDay
16%5%24424335%48%
1620
December1st to 15thDay
20%6%2442345%5%40%
1620
16th to endDay
25%8%2442434435%
1728
January1st to 15thNight
19%6%3432335%5%42%
2327
16th to endNight
18%7%3342335%5%42%
2442
February1st to 15thNight
15%5%24423346%47%
2103
16th to endNight
17%5%2442434444%
1893
March1st to 15thNight
14%5%245%24346%45%
2073
16th to endNight
12%5%24423446%47%
2112
April1st to 15thNight
12%313314448%49%
1875
16th to endNight
9%42442445%7%49%
1709
May1st to 15thNight
10%424435%5%47%45%
1619
16th to endNight
7%3245%345%6%10%46%
1682
June1st to 15thNight
6%4246%35%6%7%10%42%
1620
16th to endNight
5%3145%25%6%8%12%44%
1620
July1st to 15thNight
6%336%6%36%6%8%10%38%
1620
16th to endNight
5%4245%37%7%7%12%37%
1703
August1st to 15thNight
6%5%245%25%6%6%11%41%
1659
16th to endNight
10%6%25%5%35%5%6%10%36%
1910
September1st to 15thNight
9%5%35%5%36%45%8%41%
1953
16th to endNight
13%31442445%6%47%
1858
October1st to 15thNight
11%313312346%56%
1815
16th to endNight
10%42432323458%
2115
November1st to 15thNight
11%423213336%56%
2276
16th to endNight
14%6%23323345%49%
2340
December1st to 15thNight
15%6%35%423346%42%
2340
16th to endNight
22%7%35%434346%35%
2496

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
44%48%15%22%4
1612
16th to endDay
42%37%18%21%5%
1779
February1st to 15thDay
41%48%20%21%3
1752
16th to endDay
45%37%18%19%5%
1580
March1st to 15thDay
42%5%10%17%19%4
1885
16th to endDay
42%5%12%20%15%3
2112
April1st to 15thDay
39%410%21%19%4
2082
16th to endDay
35%6%9%22%20%4
2250
May1st to 15thDay
38%7%13%19%17%3
2331
16th to endDay
38%8%14%22%13%2
2435
June1st to 15thDay
41%10%17%22%7%1
2340
16th to endDay
31%9%18%24%13%2
2340
July1st to 15thDay
43%11%19%17%7%1
2201
16th to endDay
43%11%18%17%8%1
2310
August1st to 15thDay
42%11%17%20%8%1
2285
16th to endDay
51%10%13%15%8%1
2292
September1st to 15thDay
41%9%13%18%14%3
1993
16th to endDay
39%6%12%17%19%3
1848
October1st to 15thDay
33%410%16%26%9%
1815
16th to endDay
32%35%18%30%10%
1755
November1st to 15thDay
32%36%15%32%9%
1582
16th to endDay
38%38%15%26%7%
1620
December1st to 15thDay
44%5%8%19%15%6%
1620
16th to endDay
52%38%16%14%4
1728
January1st to 15thNight
42%37%18%22%4
2327
16th to endNight
43%36%19%21%6%
2442
February1st to 15thNight
39%37%20%20%8%
2112
16th to endNight
41%36%21%22%4
1893
March1st to 15thNight
40%49%18%18%8%
2073
16th to endNight
37%5%10%24%18%3
2112
April1st to 15thNight
32%411%23%22%6%
1875
16th to endNight
32%5%10%22%20%7%
1709
May1st to 15thNight
36%7%13%20%19%2
1620
16th to endNight
31%9%14%25%15%3
1684
June1st to 15thNight
33%11%20%22%10%1
1620
16th to endNight
28%10%19%23%15%3
1620
July1st to 15thNight
36%10%20%21%9%1
1530
16th to endNight
33%12%20%19%10%2
1595
August1st to 15thNight
34%10%16%24%12%1
1648
16th to endNight
41%10%16%17%13%1
1910
September1st to 15thNight
39%8%14%18%14%4
1953
16th to endNight
36%7%10%22%18%5%
1858
October1st to 15thNight
29%411%17%27%8%
1815
16th to endNight
30%35%17%30%12%
2115
November1st to 15thNight
30%35%17%30%12%
2276
16th to endNight
36%36%18%26%9%
2340
December1st to 15thNight
41%39%19%18%7%
2340
16th to endNight
49%48%15%17%4
2496

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
23%15%38%16%5%
90
16th to endDay
17%35%36%6%4
96
February1st to 15thDay
27%23%37%10%1
90
16th to endDay
32%17%39%9%1
81
March1st to 15thDay
26%15%30%20%6%1
175
16th to endDay
16%14%29%25%12%1
288
April1st to 15thDay
19%11%28%23%15%1
270
16th to endDay
15%5%26%25%22%4
270
May1st to 15thDay
15%9%29%16%16%12%
288
16th to endDay
14%317%29%22%12%
331
June1st to 15thDay
11%19%25%27%24%
315
16th to endDay
9%112%25%25%25%
315
July1st to 15thDay
11%8%22%27%28%
305
16th to endDay
11%6%17%36%27%
326
August1st to 15thDay
15%27%23%28%22%
313
16th to endDay
13%210%25%28%18%
332
September1st to 15thDay
13%7%10%21%28%17%
315
16th to endDay
18%317%27%24%9%
266
October1st to 15thDay
17%323%26%21%7%
255
16th to endDay
14%7%20%25%26%5%
267
November1st to 15thDay
28%16%20%20%12%2
90
16th to endDay
13%15%35%21%12%2
90
December1st to 15thDay
24%15%35%22%2
90
16th to endDay
38%14%29%15%2
96
January1st to 15thNight
25%15%29%21%7%
720
16th to endNight
22%16%32%25%3
768
February1st to 15thNight
20%15%32%27%4
704
16th to endNight
19%19%34%23%3
631
March1st to 15thNight
18%16%34%24%6%
720
16th to endNight
17%11%29%29%12%
768
April1st to 15thNight
15%11%29%26%16%
617
16th to endNight
11%7%26%36%16%1
540
May1st to 15thNight
10%7%26%30%23%2
540
16th to endNight
10%216%32%31%6%
563
June1st to 15thNight
8%110%35%34%10%
540
16th to endNight
5%8%34%40%11%
540
July1st to 15thNight
6%18%25%45%12%
510
16th to endNight
6%16%24%49%11%
564
August1st to 15thNight
9%8%28%42%10%
539
16th to endNight
12%28%25%40%9%
573
September1st to 15thNight
12%211%27%35%9%
693
16th to endNight
15%118%33%30%1
673
October1st to 15thNight
12%5%24%28%23%5%
660
16th to endNight
11%8%24%30%20%3
704
November1st to 15thNight
13%8%26%27%23%1
700
16th to endNight
18%15%25%26%13%
720
December1st to 15thNight
17%15%30%26%9%
720
16th to endNight
26%12%28%25%6%
768
Page generated at 2017-09-20 04:49:49. Version ac04

Copyright 2017 A. Danko


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