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 2017-09-18.

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%
14941
19%
46846
8%
14909
41%
14909
22%
30181

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
20%
720
20%
2506
8%
716
36%
716
18%
1581
January16th to endNight
19%
768
21%
2664
6%
768
40%
768
17%
1675
February1st to 15thNight
19%
704
17%
2198
5%
701
34%
701
17%
1468
February16th to endNight
19%
631
24%
1893
7%
631
40%
631
20%
1237
March1st to 15thNight
17%
720
17%
2160
6%
720
30%
720
17%
1454
March16th to endNight
22%
768
24%
2004
8%
768
35%
768
24%
1318
April1st to 15thNight
19%
718
17%
1796
4%
718
27%
718
22%
1276
April16th to endNight
23%
648
18%
1728
4%
648
32%
648
22%
1166
May1st to 15thNight
22%
528
17%
1608
6%
528
32%
528
17%
1103
May16th to endNight
33%
375
13%
1497
9%
374
41%
374
18%
946
June1st to 15thNight
35%
360
14%
1440
10%
360
48%
360
18%
922
June16th to endNight
41%
360
14%
1440
13%
360
50%
360
25%
812
July1st to 15thNight
45%
340
12%
1360
14%
340
50%
340
22%
800
July16th to endNight
50%
376
15%
1418
16%
354
57%
354
23%
845
August1st to 15thNight
49%
500
17%
1571
11%
498
54%
498
29%
944
August16th to endNight
53%
764
20%
1910
10%
764
56%
764
34%
1242
September1st to 15thNight
41%
720
21%
1821
10%
720
46%
720
31%
1194
September16th to endNight
47%
669
26%
1847
18%
669
53%
669
34%
1121
October1st to 15thNight
36%
660
22%
1889
12%
660
47%
660
26%
1228
October16th to endNight
27%
704
16%
2244
7%
704
40%
704
20%
1464
November1st to 15thNight
31%
700
21%
2277
10%
700
46%
700
22%
1442
November16th to endNight
26%
720
20%
2367
8%
720
40%
720
19%
1541
December1st to 15thNight
24%
720
17%
2520
6%
720
38%
720
18%
1620
December16th to endNight
20%
768
19%
2688
6%
768
36%
768
15%
1782

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
16%5%25%5%3445%7%39%
47956
Night
16%6%2442445%6%41%
47016
Cloud CoverDay
16%5%25%43445%7%39%
47966
Night
16%6%2442445%6%41%
47021
TransparencyDay
43%411%22%15%2
47644
Night
42%412%22%15%2
46846
SeeingDay
21%11%28%22%10%3
5817
Night
21%11%31%26%8%
14941

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
15%6%245%246%5%6%40%
1432
16th to endDay
14%7%244345%5%7%41%
1560
February1st to 15thDay
14%7%26%6%36%5%5%6%34%
1663
16th to endDay
15%7%35%5%34345%39%
1580
March1st to 15thDay
18%6%26%5%34448%36%
1790
16th to endDay
17%6%35%423446%41%
2217
April1st to 15thDay
17%7%35%5%2345%5%38%
2152
16th to endDay
17%424423447%44%
2231
May1st to 15thDay
23%6%35%42435%7%33%
2352
16th to endDay
17%5%25%5%3345%7%39%
2618
June1st to 15thDay
22%6%2443446%7%34%
2520
16th to endDay
13%5%25%5%35%5%6%9%36%
2520
July1st to 15thDay
11%436%6%46%5%6%8%36%
2520
16th to endDay
12%425%5%35%6%6%7%38%
2654
August1st to 15thDay
12%426%6%45%5%6%7%37%
2364
16th to endDay
11%425%435%46%8%43%
2292
September1st to 15thDay
12%5%16%5%24446%44%
2139
16th to endDay
14%413424347%48%
1838
October1st to 15thDay
20%6%24424346%41%
1740
16th to endDay
17%5%135%25%448%41%
1627
November1st to 15thDay
19%5%23424337%43%
1581
16th to endDay
18%5%34323446%43%
1590
December1st to 15thDay
17%425%5%15%5%46%40%
1440
16th to endDay
18%8%25%5%245%47%35%
1536
January1st to 15thNight
16%6%25%5%2345%6%41%
2506
16th to endNight
14%8%35%42335%6%41%
2664
February1st to 15thNight
14%8%346%2445%6%39%
2197
16th to endNight
15%6%25%5%24345%43%
1893
March1st to 15thNight
18%6%2442445%6%39%
2147
16th to endNight
16%6%24313446%45%
2004
April1st to 15thNight
16%7%25%5%345%45%39%
1796
16th to endNight
19%6%25%42334442%
1728
May1st to 15thNight
20%7%245%33447%36%
1608
16th to endNight
19%5%2432445%8%38%
1495
June1st to 15thNight
22%5%24324447%39%
1440
16th to endNight
14%324425%45%8%44%
1440
July1st to 15thNight
13%425%5%3446%10%40%
1440
16th to endNight
10%425%6%445%6%9%40%
1514
August1st to 15thNight
10%5%1443446%8%46%
1581
16th to endNight
13%4145%25%46%6%45%
1910
September1st to 15thNight
15%425%42435%6%46%
1821
16th to endNight
14%414413435%52%
1847
October1st to 15thNight
18%5%25%423345%44%
1889
16th to endNight
19%4245%24346%40%
2244
November1st to 15thNight
17%5%35%423445%44%
2277
16th to endNight
19%6%24425%445%39%
2367
December1st to 15thNight
18%5%25%42445%6%38%
2520
16th to endNight
20%7%24424446%38%
2688

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
15%6%244245%6%6%40%
1432
16th to endDay
14%7%24325%5%5%7%41%
1560
February1st to 15thDay
15%6%25%6%36%6%5%6%34%
1663
16th to endDay
15%7%25%5%35%445%40%
1580
March1st to 15thDay
18%5%25%5%24348%36%
1800
16th to endDay
17%6%34423345%43%
2217
April1st to 15thDay
18%6%25%5%2435%6%38%
2152
16th to endDay
17%42442445%5%44%
2231
May1st to 15thDay
23%5%3442445%6%33%
2352
16th to endDay
18%5%25%43445%7%38%
2618
June1st to 15thDay
21%6%2442445%7%34%
2520
16th to endDay
13%5%25%435%5%6%9%36%
2520
July1st to 15thDay
11%5%36%6%36%5%6%8%37%
2520
16th to endDay
11%5%25%5%36%5%6%8%38%
2654
August1st to 15thDay
12%5%25%5%45%6%6%8%37%
2364
16th to endDay
11%425%4345%5%7%44%
2292
September1st to 15thDay
13%5%25%5%33446%44%
2139
16th to endDay
15%32432335%6%49%
1838
October1st to 15thDay
19%6%24333345%42%
1740
16th to endDay
17%423434447%41%
1627
November1st to 15thDay
18%6%24423336%43%
1581
16th to endDay
18%5%24323346%43%
1590
December1st to 15thDay
17%5%35%5%245%46%40%
1440
16th to endDay
19%7%35%5%2445%7%35%
1536
January1st to 15thNight
16%6%25%42345%6%41%
2506
16th to endNight
15%7%35%42335%6%41%
2664
February1st to 15thNight
13%8%35%5%345%46%39%
2190
16th to endNight
16%6%245%34345%42%
1893
March1st to 15thNight
18%6%2442435%6%38%
2160
16th to endNight
16%6%3432335%6%44%
2003
April1st to 15thNight
17%7%25%5%24436%38%
1796
16th to endNight
19%7%15%423345%42%
1728
May1st to 15thNight
21%7%25%434346%36%
1608
16th to endNight
19%5%2342445%9%38%
1495
June1st to 15thNight
22%5%2443335%6%38%
1440
16th to endNight
14%32442445%8%45%
1440
July1st to 15thNight
12%5%2443446%10%40%
1440
16th to endNight
9%5%25%6%35%5%6%9%39%
1514
August1st to 15thNight
10%4244345%6%7%46%
1581
16th to endNight
12%3245%25%46%7%45%
1910
September1st to 15thNight
14%425%42345%5%46%
1821
16th to endNight
14%5%24324336%51%
1847
October1st to 15thNight
17%5%15%5%14345%44%
1889
16th to endNight
19%5%145%2345%5%40%
2244
November1st to 15thNight
17%6%25%423345%44%
2277
16th to endNight
19%6%245%24445%39%
2367
December1st to 15thNight
19%6%3442445%6%38%
2520
16th to endNight
20%7%235%24446%37%
2688

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
42%415%24%10%2
1433
16th to endDay
41%412%26%13%1
1560
February1st to 15thDay
47%6%11%19%13%1
1666
16th to endDay
45%49%23%14%2
1580
March1st to 15thDay
47%313%22%10%2
1800
16th to endDay
43%310%21%17%4
2217
April1st to 15thDay
45%311%20%15%3
2152
16th to endDay
40%39%22%19%4
2231
May1st to 15thDay
50%5%7%20%13%2
2352
16th to endDay
44%5%12%21%14%2
2622
June1st to 15thDay
49%5%12%21%10%1
2520
16th to endDay
41%7%13%23%13%
2520
July1st to 15thDay
44%6%10%20%16%1
2371
16th to endDay
40%5%15%21%14%2
2487
August1st to 15thDay
43%6%13%20%15%
2350
16th to endDay
37%5%10%26%18%1
2292
September1st to 15thDay
39%411%22%19%2
2139
16th to endDay
36%37%24%25%2
1838
October1st to 15thDay
43%49%25%14%2
1740
16th to endDay
42%413%23%14%2
1627
November1st to 15thDay
43%412%20%17%2
1581
16th to endDay
42%310%26%14%2
1590
December1st to 15thDay
45%416%19%13%1
1440
16th to endDay
48%6%15%18%11%
1536
January1st to 15thNight
43%413%22%13%2
2506
16th to endNight
43%410%23%15%2
2664
February1st to 15thNight
46%412%21%12%2
2198
16th to endNight
43%49%23%16%2
1893
March1st to 15thNight
46%411%21%13%2
2160
16th to endNight
40%39%22%19%4
2004
April1st to 15thNight
46%49%20%16%2
1796
16th to endNight
44%38%22%17%3
1728
May1st to 15thNight
49%39%18%14%3
1608
16th to endNight
43%6%17%18%11%1
1497
June1st to 15thNight
46%5%14%20%12%1
1440
16th to endNight
36%416%26%15%
1440
July1st to 15thNight
38%5%14%24%15%1
1360
16th to endNight
39%5%15%24%11%2
1418
August1st to 15thNight
35%6%14%26%15%2
1571
16th to endNight
36%6%11%26%18%
1910
September1st to 15thNight
39%410%24%19%1
1821
16th to endNight
35%37%24%26%1
1847
October1st to 15thNight
42%311%21%17%3
1889
16th to endNight
44%413%22%14%
2244
November1st to 15thNight
42%411%20%18%3
2277
16th to endNight
46%312%23%12%2
2367
December1st to 15thNight
44%5%16%20%12%
2520
16th to endNight
47%412%21%12%
2688

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%25%35%13%5%
60
16th to endDay
29%16%41%11%1
68
February1st to 15thDay
24%20%33%20%1
179
16th to endDay
24%16%35%17%5%
239
March1st to 15thDay
28%18%30%18%3
270
16th to endDay
22%19%34%15%6%1
288
April1st to 15thDay
25%14%34%15%8%1
270
16th to endDay
24%10%32%18%10%3
270
May1st to 15thDay
37%13%21%16%9%1
288
16th to endDay
23%12%27%24%10%1
331
June1st to 15thDay
26%12%22%24%11%2
315
16th to endDay
19%10%33%26%9%1
315
July1st to 15thDay
15%5%31%30%13%3
305
16th to endDay
14%7%27%28%17%3
326
August1st to 15thDay
13%6%28%29%14%8%
313
16th to endDay
12%328%26%18%10%
332
September1st to 15thDay
14%10%25%25%13%9%
315
16th to endDay
18%6%23%22%12%15%
262
October1st to 15thDay
23%7%20%27%13%7%
255
16th to endDay
21%19%25%26%7%
247
November1st to 15thDay
25%11%26%23%11%2
235
16th to endDay
26%13%28%19%11%1
210
December1st to 15thDay
18%25%33%18%31
60
16th to endDay
34%14%37%10%3
64
January1st to 15thNight
24%14%35%21%3
720
16th to endNight
22%16%35%22%2
768
February1st to 15thNight
21%16%34%24%2
704
16th to endNight
23%16%35%21%2
631
March1st to 15thNight
25%18%35%19%2
720
16th to endNight
21%18%34%20%5%
768
April1st to 15thNight
22%16%38%19%3
718
16th to endNight
23%16%31%20%6%
648
May1st to 15thNight
25%14%33%21%4
528
16th to endNight
21%6%32%31%7%
375
June1st to 15thNight
24%6%29%30%9%
360
16th to endNight
16%333%35%11%
360
July1st to 15thNight
14%328%35%17%
340
16th to endNight
12%324%39%19%
376
August1st to 15thNight
12%426%40%15%
500
16th to endNight
13%221%38%21%1
764
September1st to 15thNight
17%5%29%33%13%1
720
16th to endNight
17%5%23%27%21%4
669
October1st to 15thNight
20%7%28%32%10%1
660
16th to endNight
24%12%33%24%6%
704
November1st to 15thNight
22%13%27%25%9%1
700
16th to endNight
25%11%30%24%7%1
720
December1st to 15thNight
23%12%35%21%5%
720
16th to endNight
26%14%34%21%2
768
Page generated at 2017-09-19 07:32:24. Version ac04

Copyright 2017 A. Danko


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