Kennelly's Mountain
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kennelly's Mountain clear sky chart from 2005-11-05 to 2017-12-04.

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
26%
14978
13%
47858
7%
14948
34%
14948
16%
34268

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
13%
720
6%
2506
2%
716
18%
716
6%
2052
January16th to endNight
17%
768
11%
2602
5%
768
24%
768
10%
1976
February1st to 15thNight
14%
702
9%
2287
3%
701
22%
701
9%
1771
February16th to endNight
17%
631
14%
1979
5%
631
29%
631
12%
1453
March1st to 15thNight
15%
720
12%
2061
5%
720
23%
720
13%
1549
March16th to endNight
28%
768
19%
2061
8%
768
36%
768
21%
1417
April1st to 15thNight
21%
718
15%
1796
4%
718
27%
718
18%
1334
April16th to endNight
29%
639
17%
1719
7%
639
36%
639
21%
1205
May1st to 15thNight
31%
363
17%
1443
14%
363
42%
363
16%
949
May16th to endNight
32%
375
14%
1497
9%
374
45%
374
18%
934
June1st to 15thNight
30%
360
9%
1440
6%
360
41%
360
15%
966
June16th to endNight
40%
360
9%
1440
10%
360
46%
360
18%
912
July1st to 15thNight
47%
340
15%
1360
20%
340
54%
340
27%
759
July16th to endNight
50%
376
14%
1418
13%
354
57%
354
27%
800
August1st to 15thNight
49%
488
13%
1559
10%
486
53%
486
26%
986
August16th to endNight
48%
681
20%
1827
10%
681
54%
681
36%
1131
September1st to 15thNight
40%
720
15%
1800
6%
720
44%
720
29%
1246
September16th to endNight
47%
717
22%
1974
15%
717
52%
717
31%
1253
October1st to 15thNight
30%
720
16%
2160
10%
720
38%
720
19%
1498
October16th to endNight
20%
768
11%
2367
5%
768
28%
768
11%
1820
November1st to 15thNight
25%
760
16%
2570
12%
760
33%
760
14%
1831
November16th to endNight
17%
780
10%
2730
6%
780
23%
780
9%
2122
December1st to 15thNight
13%
736
6%
2574
2%
736
19%
736
7%
2108
December16th to endNight
10%
768
8%
2688
3%
768
18%
768
7%
2196

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
17%9%37%6%34446%31%
48649
Night
16%10%47%5%34446%32%
48028
TransparencyDay
52%6%11%18%9%1
48337
Night
51%6%11%19%9%
47858
SeeingDay
23%14%30%19%8%3
5671
Night
22%14%30%22%8%
14980

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%13%6%10%7%3344421%
1432
16th to endDay
14%15%5%10%10%45%345%21%
1620
February1st to 15thDay
11%16%6%11%8%36%44421%
1575
16th to endDay
16%15%5%7%6%445%4425%
1494
March1st to 15thDay
15%13%48%8%45%435%25%
1887
16th to endDay
12%9%46%6%34345%39%
2163
April1st to 15thDay
21%12%36%423335%32%
2152
16th to endDay
20%9%45%32433438%
2251
May1st to 15thDay
20%8%36%5%24446%33%
2508
16th to endDay
16%6%36%5%345%5%7%34%
2618
June1st to 15thDay
22%7%35%5%3445%6%30%
2520
16th to endDay
17%6%26%5%446%5%8%32%
2520
July1st to 15thDay
13%5%25%6%35%5%6%8%36%
2520
16th to endDay
11%5%25%6%46%6%6%9%34%
2654
August1st to 15thDay
13%6%37%6%45%5%5%7%34%
2388
16th to endDay
13%5%26%5%346%5%7%37%
2363
September1st to 15thDay
17%6%25%42435%7%39%
2160
16th to endDay
14%6%245%34347%43%
1985
October1st to 15thDay
21%9%36%5%34445%31%
1800
16th to endDay
24%11%38%6%44335%23%
1857
November1st to 15thDay
15%10%36%6%34445%33%
1618
16th to endDay
20%14%6%8%5%34435%22%
1560
December1st to 15thDay
19%17%7%10%8%35%43414%
1468
16th to endDay
21%18%7%8%5%2433420%
1536
January1st to 15thNight
16%13%6%11%9%45%5%45%17%
2506
16th to endNight
12%13%5%8%8%35%445%25%
2602
February1st to 15thNight
13%14%7%10%7%45%446%22%
2285
16th to endNight
14%11%5%7%6%3446%7%28%
1979
March1st to 15thNight
16%12%6%7%7%33335%29%
2049
16th to endNight
13%8%45%6%34346%39%
2061
April1st to 15thNight
19%10%35%443445%34%
1796
16th to endNight
17%8%25%434447%37%
1719
May1st to 15thNight
20%9%35%424335%37%
1443
16th to endNight
14%6%25%4235%7%8%39%
1495
June1st to 15thNight
18%6%37%5%3445%5%36%
1440
16th to endNight
15%6%25%425%5%5%8%38%
1440
July1st to 15thNight
8%325%42445%8%48%
1440
16th to endNight
9%4244236%7%8%46%
1514
August1st to 15thNight
9%425%5%345%6%8%43%
1569
16th to endNight
9%41433435%7%50%
1827
September1st to 15thNight
15%6%245%3445%5%42%
1800
16th to endNight
14%5%24323346%48%
1974
October1st to 15thNight
19%7%25%5%23345%37%
2160
16th to endNight
22%11%36%5%34446%26%
2367
November1st to 15thNight
17%11%36%5%35%445%32%
2570
16th to endNight
20%14%48%6%34346%23%
2730
December1st to 15thNight
19%17%6%9%6%3444419%
2574
16th to endNight
22%14%6%9%7%3443419%
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
64%6%9%11%6%1
1433
16th to endDay
65%5%9%11%7%1
1620
February1st to 15thDay
65%5%10%13%4
1577
16th to endDay
60%6%9%11%10%1
1494
March1st to 15thDay
61%5%9%15%6%1
1898
16th to endDay
46%48%19%14%5%
2163
April1st to 15thDay
55%47%17%13%2
2152
16th to endDay
49%47%19%15%3
2251
May1st to 15thDay
51%5%9%16%14%2
2508
16th to endDay
47%7%12%19%11%1
2622
June1st to 15thDay
52%7%10%18%9%
2520
16th to endDay
48%8%10%19%11%1
2520
July1st to 15thDay
40%6%14%25%11%
2371
16th to endDay
44%9%14%22%8%
2487
August1st to 15thDay
46%8%15%19%9%
2374
16th to endDay
42%7%16%23%8%
2363
September1st to 15thDay
43%6%13%24%12%
2160
16th to endDay
41%6%12%29%10%
1985
October1st to 15thDay
54%5%11%19%9%
1800
16th to endDay
63%6%10%14%4
1857
November1st to 15thDay
51%6%14%17%8%
1618
16th to endDay
64%6%9%12%5%1
1560
December1st to 15thDay
71%6%9%10%2
1468
16th to endDay
68%5%10%10%5%
1536
January1st to 15thNight
67%7%10%9%4
2506
16th to endNight
59%6%9%15%7%
2602
February1st to 15thNight
61%6%12%14%4
2287
16th to endNight
54%6%10%18%9%
1979
March1st to 15thNight
58%411%18%7%
2061
16th to endNight
45%5%11%20%15%2
2061
April1st to 15thNight
52%5%8%18%14%1
1796
16th to endNight
46%5%7%20%16%2
1719
May1st to 15thNight
48%5%8%18%15%3
1443
16th to endNight
41%8%12%21%13%2
1497
June1st to 15thNight
48%7%12%20%11%
1440
16th to endNight
42%8%14%21%13%
1440
July1st to 15thNight
33%6%13%28%16%1
1360
16th to endNight
33%7%18%26%14%
1418
August1st to 15thNight
36%10%18%23%11%1
1559
16th to endNight
32%6%16%32%11%
1827
September1st to 15thNight
41%7%13%26%10%
1800
16th to endNight
37%5%13%35%8%
1974
October1st to 15thNight
47%6%11%21%13%
2160
16th to endNight
58%6%12%16%5%
2367
November1st to 15thNight
52%6%12%17%9%
2570
16th to endNight
62%6%11%15%3
2730
December1st to 15thNight
67%7%10%11%2
2574
16th to endNight
68%5%9%10%5%
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
31%21%25%13%8%
60
16th to endDay
37%14%35%11%1
78
February1st to 15thDay
38%21%34%32
90
16th to endDay
33%22%29%10%3
153
March1st to 15thDay
26%18%34%15%4
270
16th to endDay
25%19%30%14%9%1
288
April1st to 15thDay
28%24%25%13%6%1
270
16th to endDay
30%17%24%15%10%1
270
May1st to 15thDay
30%12%27%18%6%4
288
16th to endDay
22%15%35%17%6%2
331
June1st to 15thDay
28%12%30%19%8%
315
16th to endDay
16%12%35%22%10%1
315
July1st to 15thDay
13%7%34%30%10%4
305
16th to endDay
13%7%34%27%11%4
326
August1st to 15thDay
14%6%30%31%8%8%
313
16th to endDay
15%7%29%26%11%9%
332
September1st to 15thDay
17%8%27%19%15%11%
315
16th to endDay
15%7%28%21%17%9%
314
October1st to 15thDay
25%16%26%21%8%2
315
16th to endDay
32%18%30%14%4
320
November1st to 15thDay
25%14%29%19%8%2
182
16th to endDay
32%20%37%5%22
90
December1st to 15thDay
22%25%32%17%1
67
16th to endDay
40%29%26%3
64
January1st to 15thNight
24%22%32%15%3
720
16th to endNight
21%17%35%20%4
768
February1st to 15thNight
20%19%39%17%3
704
16th to endNight
21%19%37%16%4
631
March1st to 15thNight
26%19%33%17%2
720
16th to endNight
20%17%28%23%8%1
768
April1st to 15thNight
27%18%30%19%4
718
16th to endNight
23%16%28%23%7%
639
May1st to 15thNight
25%10%27%26%8%1
363
16th to endNight
17%9%35%27%9%
375
June1st to 15thNight
19%11%32%28%8%
360
16th to endNight
18%7%30%31%11%
360
July1st to 15thNight
8%7%32%37%13%1
340
16th to endNight
9%330%40%15%
376
August1st to 15thNight
11%424%40%17%1
488
16th to endNight
11%430%32%18%1
681
September1st to 15thNight
19%6%28%25%16%2
720
16th to endNight
18%8%22%28%19%2
717
October1st to 15thNight
23%12%29%23%10%1
720
16th to endNight
29%15%30%18%6%
768
November1st to 15thNight
23%15%31%21%8%
760
16th to endNight
30%19%26%15%6%
780
December1st to 15thNight
28%21%31%15%2
736
16th to endNight
33%15%32%14%2
768
Page generated at 2017-12-05 10:19:02. Version ac04

Copyright 2017 A. Danko


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