Cayuga
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cayuga clear sky chart from 2005-11-05 to 2017-08-12.

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
37%
14768
15%
46550
10%
14732
42%
14732
19%
32184

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
16%
716
11%
2431
6%
716
24%
716
9%
1901
January16th to endNight
16%
768
11%
2496
4%
768
25%
768
10%
1918
February1st to 15thNight
17%
701
8%
2287
1%
701
25%
701
10%
1802
February16th to endNight
25%
631
11%
1997
5%
631
32%
631
13%
1495
March1st to 15thNight
26%
720
14%
1980
8%
720
31%
720
16%
1514
March16th to endNight
33%
768
20%
2112
10%
768
40%
768
24%
1461
April1st to 15thNight
31%
718
15%
1833
6%
718
36%
718
22%
1347
April16th to endNight
42%
558
20%
1638
9%
558
50%
558
27%
1059
May1st to 15thNight
46%
531
16%
1611
11%
531
51%
531
25%
1068
May16th to endNight
52%
374
18%
1497
18%
374
60%
374
23%
858
June1st to 15thNight
50%
360
14%
1440
14%
360
58%
360
21%
860
June16th to endNight
56%
360
13%
1440
17%
360
62%
360
24%
848
July1st to 15thNight
66%
340
17%
1360
24%
340
69%
340
33%
694
July16th to endNight
63%
538
16%
1569
14%
505
66%
505
33%
917
August1st to 15thNight
68%
527
18%
1575
15%
524
70%
524
36%
927
August16th to endNight
67%
569
22%
1619
15%
569
71%
569
37%
948
September1st to 15thNight
56%
660
23%
1677
13%
660
60%
660
33%
1086
September16th to endNight
56%
657
22%
1826
15%
657
59%
657
32%
1146
October1st to 15thNight
44%
660
18%
1980
17%
660
49%
660
25%
1308
October16th to endNight
25%
704
13%
2112
7%
704
33%
704
17%
1531
November1st to 15thNight
38%
700
20%
2342
17%
700
45%
700
23%
1504
November16th to endNight
25%
720
12%
2520
7%
720
31%
720
13%
1803
December1st to 15thNight
17%
720
7%
2520
3%
720
21%
720
9%
1967
December16th to endNight
15%
768
6%
2688
2%
768
20%
768
7%
2222

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%9%46%5%35%45%7%32%
47415
Night
15%9%36%5%3445%6%34%
46732
Cloud CoverDay
14%9%46%6%35%45%7%32%
47425
Night
15%8%36%5%3445%6%34%
46736
TransparencyDay
49%5%13%20%10%1
47115
Night
49%5%12%20%10%1
46550
SeeingDay
17%7%23%26%17%7%
5210
Night
20%7%26%30%13%1
14776

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
19%15%6%10%6%35%445%19%
1504
16th to endDay
14%17%6%12%9%35%445%16%
1728
February1st to 15thDay
16%18%6%9%8%45%34418%
1575
16th to endDay
18%13%6%9%7%35%345%22%
1473
March1st to 15thDay
17%12%5%9%7%35%447%24%
1969
16th to endDay
16%11%5%6%5%34346%31%
2112
April1st to 15thDay
19%10%5%6%424445%30%
2114
16th to endDay
18%7%35%423347%38%
2331
May1st to 15thDay
14%7%36%6%45%45%6%35%
2340
16th to endDay
11%5%25%5%345%5%7%42%
2618
June1st to 15thDay
13%6%345%345%6%8%38%
2520
16th to endDay
11%5%24435%6%6%9%40%
2520
July1st to 15thDay
7%5%25%435%5%6%10%42%
2520
16th to endDay
10%5%25%5%46%6%8%9%36%
2489
August1st to 15thDay
9%425%5%36%6%8%10%38%
2288
16th to endDay
11%5%25%43445%8%43%
2220
September1st to 15thDay
13%5%35%4345%5%8%38%
1950
16th to endDay
14%5%25%5%3446%7%38%
1804
October1st to 15thDay
18%7%26%6%35%346%35%
1650
16th to endDay
21%11%47%6%35%445%24%
1760
November1st to 15thDay
13%7%35%5%45%46%8%35%
1514
16th to endDay
19%13%47%5%3436%7%24%
1440
December1st to 15thDay
19%15%6%8%5%3445%6%20%
1440
16th to endDay
22%15%7%9%7%34445%14%
1536
January1st to 15thNight
21%14%5%9%6%24435%22%
2431
16th to endNight
14%15%7%10%6%2445%5%22%
2496
February1st to 15thNight
15%15%6%10%6%35%445%22%
2285
16th to endNight
17%11%5%8%6%35%446%26%
1997
March1st to 15thNight
19%9%47%6%345%46%27%
1968
16th to endNight
16%8%46%423346%38%
2112
April1st to 15thNight
19%9%35%5%2435%5%34%
1833
16th to endNight
11%6%25%6%345%5%5%43%
1638
May1st to 15thNight
18%425%5%2445%7%38%
1611
16th to endNight
11%4245%245%6%7%45%
1495
June1st to 15thNight
11%6%345%35%6%6%8%39%
1440
16th to endNight
8%5%246%35%6%5%7%43%
1440
July1st to 15thNight
5%3244245%5%8%54%
1440
16th to endNight
7%3144245%7%8%48%
1676
August1st to 15thNight
7%3135%346%7%10%46%
1586
16th to endNight
8%314435%45%6%51%
1619
September1st to 15thNight
13%6%2442345%7%46%
1677
16th to endNight
12%5%25%5%23446%47%
1826
October1st to 15thNight
15%7%25%42345%6%41%
1980
16th to endNight
21%9%35%5%345%5%6%29%
2112
November1st to 15thNight
14%7%25%42445%8%38%
2342
16th to endNight
20%10%45%5%24446%29%
2520
December1st to 15thNight
22%14%5%7%43345%6%21%
2520
16th to endNight
21%13%7%9%6%3445%5%16%
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
19%15%6%9%6%35%445%19%
1504
16th to endDay
13%17%6%12%10%35%446%16%
1728
February1st to 15thDay
15%18%7%10%8%35%335%17%
1575
16th to endDay
18%12%6%8%8%34445%22%
1473
March1st to 15thDay
17%12%5%8%7%34446%24%
1980
16th to endDay
15%11%5%6%5%24446%32%
2111
April1st to 15thDay
19%11%47%5%24446%30%
2114
16th to endDay
18%7%35%423447%38%
2331
May1st to 15thDay
14%7%36%7%35%45%6%35%
2340
16th to endDay
11%5%35%4345%5%7%42%
2618
June1st to 15thDay
12%7%25%5%35%5%5%9%38%
2520
16th to endDay
11%5%15%425%6%6%9%40%
2520
July1st to 15thDay
7%5%245%35%47%10%42%
2520
16th to endDay
10%5%25%5%46%6%8%10%35%
2489
August1st to 15thDay
8%425%5%35%6%8%10%38%
2288
16th to endDay
11%5%25%5%34448%43%
2220
September1st to 15thDay
13%435%5%445%5%7%38%
1950
16th to endDay
14%5%245%3446%7%38%
1804
October1st to 15thDay
18%7%36%6%34346%35%
1650
16th to endDay
21%11%37%7%35%45%5%24%
1760
November1st to 15thDay
12%7%36%5%45%45%8%34%
1514
16th to endDay
19%12%47%5%3446%7%24%
1440
December1st to 15thDay
18%14%6%8%5%3335%7%20%
1440
16th to endDay
22%15%7%9%7%3445%5%14%
1536
January1st to 15thNight
21%13%5%9%5%34445%22%
2431
16th to endNight
14%15%7%10%5%2446%5%22%
2496
February1st to 15thNight
15%15%5%9%6%45%445%22%
2278
16th to endNight
16%11%5%8%6%3445%6%26%
1997
March1st to 15thNight
20%9%47%6%345%46%27%
1980
16th to endNight
16%8%46%423346%38%
2112
April1st to 15thNight
19%8%36%5%2435%6%33%
1833
16th to endNight
11%6%25%6%245%45%43%
1638
May1st to 15thNight
17%5%25%6%2445%7%37%
1610
16th to endNight
11%42443446%7%45%
1495
June1st to 15thNight
11%6%35%435%5%6%8%39%
1440
16th to endNight
8%5%246%35%5%6%7%43%
1440
July1st to 15thNight
5%3234245%5%9%53%
1440
16th to endNight
7%414425%47%8%48%
1676
August1st to 15thNight
7%3145%346%7%9%47%
1586
16th to endNight
8%314435%45%6%52%
1619
September1st to 15thNight
13%6%2442345%7%46%
1677
16th to endNight
12%5%25%5%235%47%46%
1826
October1st to 15thNight
16%7%25%42345%6%41%
1980
16th to endNight
21%9%35%4345%5%6%29%
2112
November1st to 15thNight
14%7%25%42446%8%38%
2342
16th to endNight
20%10%45%5%34446%29%
2520
December1st to 15thNight
22%15%5%7%42346%6%21%
2520
16th to endNight
21%12%8%10%6%35%45%5%16%
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
66%410%14%4
1505
16th to endDay
69%5%10%11%3
1728
February1st to 15thDay
69%48%12%4
1577
16th to endDay
63%411%14%5%
1473
March1st to 15thDay
60%5%12%16%4
1980
16th to endDay
53%49%21%9%1
2112
April1st to 15thDay
54%411%18%11%
2114
16th to endDay
45%411%20%15%2
2331
May1st to 15thDay
46%5%12%23%11%
2340
16th to endDay
39%5%15%24%13%1
2622
June1st to 15thDay
41%6%13%24%12%1
2520
16th to endDay
36%8%15%23%14%
2520
July1st to 15thDay
33%7%12%25%18%1
2371
16th to endDay
39%8%15%22%12%1
2333
August1st to 15thDay
35%7%18%23%13%1
2275
16th to endDay
37%414%28%13%1
2220
September1st to 15thDay
42%6%14%24%11%
1950
16th to endDay
41%6%15%24%11%
1804
October1st to 15thDay
49%413%20%11%1
1650
16th to endDay
60%5%13%15%3
1760
November1st to 15thDay
45%7%16%19%9%1
1514
16th to endDay
59%5%13%14%7%
1440
December1st to 15thDay
64%5%14%12%2
1440
16th to endDay
71%6%9%10%1
1536
January1st to 15thNight
64%410%13%6%
2431
16th to endNight
61%5%11%15%5%
2496
February1st to 15thNight
64%5%11%13%5%
2287
16th to endNight
58%412%17%6%
1997
March1st to 15thNight
58%5%10%18%6%
1980
16th to endNight
46%49%22%14%2
2112
April1st to 15thNight
51%49%20%13%
1833
16th to endNight
41%410%20%18%4
1638
May1st to 15thNight
45%410%25%11%2
1611
16th to endNight
36%6%11%25%16%3
1497
June1st to 15thNight
40%6%10%25%15%1
1440
16th to endNight
38%6%14%23%16%1
1440
July1st to 15thNight
27%6%11%26%23%3
1360
16th to endNight
31%7%15%25%17%3
1569
August1st to 15thNight
29%7%17%29%13%1
1575
16th to endNight
31%5%13%30%16%2
1619
September1st to 15thNight
37%5%12%27%15%1
1677
16th to endNight
37%411%30%14%1
1826
October1st to 15thNight
43%411%23%15%1
1980
16th to endNight
53%5%14%18%6%
2112
November1st to 15thNight
42%6%14%22%13%1
2342
16th to endNight
55%414%17%6%
2520
December1st to 15thNight
63%5%14%13%3
2520
16th to endNight
69%6%10%10%2
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
22%27%30%6%11%1
72
16th to endDay
26%14%37%18%3
96
February1st to 15thDay
18%14%48%17%
90
16th to endDay
14%19%35%28%1
87
March1st to 15thDay
24%9%30%24%11%
270
16th to endDay
24%6%32%23%11%2
288
April1st to 15thDay
26%9%26%24%10%2
270
16th to endDay
19%429%25%14%7%
270
May1st to 15thDay
20%424%27%15%6%
288
16th to endDay
12%6%25%29%17%8%
331
June1st to 15thDay
13%7%20%34%21%2
315
16th to endDay
15%5%24%28%20%5%
315
July1st to 15thDay
11%316%31%26%10%
305
16th to endDay
11%320%29%22%12%
326
August1st to 15thDay
9%114%29%27%17%
297
16th to endDay
13%112%23%27%21%
268
September1st to 15thDay
10%215%23%28%18%
255
16th to endDay
20%315%23%21%15%
254
October1st to 15thDay
20%5%18%25%20%9%
255
16th to endDay
24%10%27%27%9%
272
November1st to 15thDay
10%12%28%32%12%2
102
16th to endDay
21%18%31%18%8%1
60
December1st to 15thDay
18%28%33%11%8%
60
16th to endDay
29%28%32%7%1
64
January1st to 15thNight
27%15%31%19%5%
720
16th to endNight
23%13%35%21%5%
768
February1st to 15thNight
24%14%32%24%4
704
16th to endNight
22%10%30%31%4
631
March1st to 15thNight
25%10%28%28%7%
720
16th to endNight
19%5%33%29%10%1
768
April1st to 15thNight
23%8%28%32%6%
718
16th to endNight
13%6%30%36%12%1
558
May1st to 15thNight
18%222%35%19%1
531
16th to endNight
12%421%38%20%1
375
June1st to 15thNight
14%226%36%18%
360
16th to endNight
11%121%46%18%
360
July1st to 15thNight
6%216%45%27%2
340
16th to endNight
10%116%43%25%2
538
August1st to 15thNight
8%112%41%31%4
527
16th to endNight
9%211%36%35%4
569
September1st to 15thNight
15%415%32%25%6%
660
16th to endNight
16%316%28%29%6%
657
October1st to 15thNight
19%6%20%30%19%2
660
16th to endNight
26%8%32%26%5%
704
November1st to 15thNight
19%6%28%29%13%2
700
16th to endNight
25%13%28%22%8%1
720
December1st to 15thNight
30%14%30%20%4
720
16th to endNight
28%11%34%21%4
768
Page generated at 2017-08-13 14:16:21. Version ac04

Copyright 2017 A. Danko


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