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 2017-03-15.

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%
14143
13%
45230
7%
14113
33%
14113
15%
32498

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%
704
18%
1889
8%
704
36%
704
21%
1301
April1st to 15thNight
20%
658
15%
1646
4%
658
27%
658
18%
1225
April16th to endNight
30%
586
18%
1576
7%
586
37%
586
22%
1093
May1st to 15thNight
32%
333
18%
1323
15%
333
44%
333
18%
849
May16th to endNight
32%
343
14%
1369
10%
342
45%
342
19%
843
June1st to 15thNight
28%
330
9%
1320
6%
330
39%
330
14%
904
June16th to endNight
41%
330
9%
1320
10%
330
48%
330
19%
820
July1st to 15thNight
48%
310
15%
1240
21%
310
55%
310
28%
679
July16th to endNight
50%
348
13%
1306
11%
326
56%
326
27%
738
August1st to 15thNight
48%
447
14%
1428
10%
445
52%
445
26%
898
August16th to endNight
48%
624
19%
1674
9%
624
54%
624
35%
1043
September1st to 15thNight
39%
660
15%
1650
6%
660
42%
660
28%
1147
September16th to endNight
44%
657
20%
1809
12%
657
49%
657
30%
1163
October1st to 15thNight
29%
660
16%
1980
10%
660
38%
660
18%
1397
October16th to endNight
20%
704
10%
2170
4%
704
27%
704
11%
1692
November1st to 15thNight
25%
700
17%
2367
13%
700
33%
700
14%
1685
November16th to endNight
17%
720
10%
2520
6%
720
23%
720
9%
1963
December1st to 15thNight
13%
720
6%
2520
2%
720
19%
720
7%
2061
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%47%6%34446%31%
45517
Night
16%10%47%5%34446%32%
45400
TransparencyDay
53%6%11%17%9%1
45205
Night
52%6%11%18%9%
45230
SeeingDay
22%13%31%19%9%3
4689
Night
22%14%31%22%8%
14145

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%
1885
16th to endDay
11%9%46%6%34445%39%
1983
April1st to 15thDay
21%12%36%433335%32%
1972
16th to endDay
20%8%35%32433438%
2063
May1st to 15thDay
18%8%36%5%24446%35%
2298
16th to endDay
15%6%36%5%35%5%5%7%35%
2394
June1st to 15thDay
22%8%45%5%3445%6%29%
2310
16th to endDay
17%6%26%5%446%5%8%32%
2310
July1st to 15thDay
13%5%25%6%36%5%6%8%36%
2310
16th to endDay
11%5%25%6%46%6%6%9%34%
2458
August1st to 15thDay
14%6%37%5%45%5%5%7%35%
2189
16th to endDay
13%5%26%6%346%5%7%37%
2165
September1st to 15thDay
18%6%25%42435%7%38%
1980
16th to endDay
15%6%245%34446%41%
1820
October1st to 15thDay
22%9%26%5%34445%30%
1650
16th to endDay
26%11%38%6%34335%23%
1702
November1st to 15thDay
15%10%36%6%245%45%34%
1491
16th to endDay
20%14%6%8%5%34435%22%
1440
December1st to 15thDay
19%16%7%10%9%35%43415%
1440
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
12%8%45%5%34346%39%
1889
April1st to 15thNight
18%10%35%444435%34%
1646
16th to endNight
17%8%25%424347%38%
1576
May1st to 15thNight
18%8%35%424336%39%
1323
16th to endNight
14%6%244235%6%7%40%
1367
June1st to 15thNight
18%6%37%5%3445%5%35%
1320
16th to endNight
15%5%25%325%5%5%8%40%
1320
July1st to 15thNight
8%335%42445%9%48%
1320
16th to endNight
8%4244236%7%8%46%
1402
August1st to 15thNight
9%425%6%3446%8%44%
1438
16th to endNight
9%425%33435%6%50%
1674
September1st to 15thNight
16%7%245%34445%42%
1650
16th to endNight
15%5%24323346%47%
1809
October1st to 15thNight
20%8%25%5%23445%35%
1980
16th to endNight
23%12%37%5%34445%24%
2170
November1st to 15thNight
16%11%36%435%445%32%
2367
16th to endNight
20%14%49%6%34346%23%
2520
December1st to 15thNight
19%17%6%9%6%3444420%
2520
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
1896
16th to endDay
46%5%8%20%14%5%
1983
April1st to 15thDay
55%37%16%13%2
1972
16th to endDay
49%47%17%17%3
2063
May1st to 15thDay
49%5%9%16%15%2
2298
16th to endDay
46%7%12%19%12%2
2398
June1st to 15thDay
53%7%10%17%10%
2310
16th to endDay
47%7%10%20%12%1
2310
July1st to 15thDay
40%6%14%25%11%
2161
16th to endDay
44%9%14%21%8%
2291
August1st to 15thDay
46%7%14%20%10%
2175
16th to endDay
43%7%16%22%8%
2165
September1st to 15thDay
44%6%13%24%11%
1980
16th to endDay
42%6%12%27%10%
1820
October1st to 15thDay
55%5%10%18%9%
1650
16th to endDay
64%6%10%13%4
1702
November1st to 15thDay
50%7%15%18%8%
1491
16th to endDay
64%5%10%12%5%1
1440
December1st to 15thDay
71%6%9%10%2
1440
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%14%2
1889
April1st to 15thNight
52%5%7%18%14%1
1646
16th to endNight
46%47%20%17%3
1576
May1st to 15thNight
46%5%8%19%17%3
1323
16th to endNight
39%8%11%21%15%2
1369
June1st to 15thNight
49%7%11%19%10%1
1320
16th to endNight
40%8%14%21%14%
1320
July1st to 15thNight
31%6%14%29%16%1
1240
16th to endNight
33%7%18%24%15%
1306
August1st to 15thNight
36%9%17%23%12%1
1428
16th to endNight
33%6%16%31%11%
1674
September1st to 15thNight
42%6%13%26%10%
1650
16th to endNight
38%5%13%33%8%
1809
October1st to 15thNight
49%6%11%19%12%
1980
16th to endNight
60%6%12%14%5%
2170
November1st to 15thNight
52%6%11%17%10%
2367
16th to endNight
62%6%11%15%3
2520
December1st to 15thNight
66%7%10%11%2
2520
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
269
16th to endDay
23%20%27%15%11%1
224
April1st to 15thDay
27%25%23%14%8%1
210
16th to endDay
25%14%26%17%13%2
210
May1st to 15thDay
24%11%30%21%7%5%
228
16th to endDay
19%14%36%18%7%2
267
June1st to 15thDay
29%11%29%18%9%1
255
16th to endDay
15%9%34%25%11%2
255
July1st to 15thDay
12%5%35%29%11%4
245
16th to endDay
11%8%36%27%11%4
270
August1st to 15thDay
15%6%29%30%8%9%
253
16th to endDay
14%6%30%27%11%9%
268
September1st to 15thDay
18%7%29%18%16%10%
255
16th to endDay
18%7%33%21%12%6%
254
October1st to 15thDay
26%15%24%23%7%2
255
16th to endDay
33%16%32%13%4
261
November1st to 15thDay
23%13%31%19%11%1
145
16th to endDay
33%15%36%8%33
60
December1st to 15thDay
21%26%33%16%1
60
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
19%18%27%23%8%1
704
April1st to 15thNight
26%19%31%19%3
658
16th to endNight
23%15%29%23%7%
586
May1st to 15thNight
23%9%30%26%8%1
333
16th to endNight
18%8%36%27%10%
343
June1st to 15thNight
19%12%33%26%7%
330
16th to endNight
19%6%28%32%12%
330
July1st to 15thNight
7%7%31%38%13%1
310
16th to endNight
8%332%39%15%
348
August1st to 15thNight
11%425%40%16%1
447
16th to endNight
12%431%33%16%1
624
September1st to 15thNight
20%7%29%24%16%2
660
16th to endNight
19%8%24%28%17%1
657
October1st to 15thNight
25%12%28%22%9%
660
16th to endNight
30%15%28%18%6%
704
November1st to 15thNight
22%15%31%21%7%1
700
16th to endNight
31%19%26%15%6%
720
December1st to 15thNight
28%21%31%15%2
720
16th to endNight
33%15%32%14%2
768
Page generated at 2017-03-16 11:05:31. Version ac04

Copyright 2017 A. Danko


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