Long Point on Lake Chautauqua
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Long Point on Lake Chautauqua 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
27%
14834
12%
46552
7%
14796
32%
14796
14%
35010

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
7%
716
5%
2424
3%
716
11%
716
4%
2140
January16th to endNight
9%
768
5%
2496
2%
768
13%
768
4%
2213
February1st to 15thNight
8%
703
5%
2287
2%
701
12%
701
5%
1984
February16th to endNight
11%
631
8%
1985
2%
631
19%
631
7%
1647
March1st to 15thNight
15%
720
11%
1980
6%
720
20%
720
10%
1620
March16th to endNight
23%
768
16%
2112
7%
768
29%
768
15%
1592
April1st to 15thNight
21%
718
12%
1824
4%
718
26%
718
18%
1382
April16th to endNight
29%
591
18%
1671
6%
591
38%
591
23%
1131
May1st to 15thNight
34%
534
15%
1614
8%
534
40%
534
19%
1143
May16th to endNight
42%
374
18%
1497
17%
374
50%
374
21%
897
June1st to 15thNight
41%
360
13%
1440
10%
360
51%
360
19%
886
June16th to endNight
43%
360
13%
1440
15%
360
50%
360
20%
903
July1st to 15thNight
54%
340
15%
1360
20%
340
58%
340
27%
755
July16th to endNight
54%
547
15%
1578
12%
514
58%
514
30%
964
August1st to 15thNight
59%
527
17%
1575
13%
524
62%
524
31%
949
August16th to endNight
58%
588
17%
1638
11%
588
60%
588
32%
1030
September1st to 15thNight
48%
660
21%
1663
12%
660
53%
660
29%
1141
September16th to endNight
43%
657
18%
1837
12%
657
48%
657
24%
1265
October1st to 15thNight
36%
660
15%
1980
13%
660
41%
660
20%
1376
October16th to endNight
16%
704
10%
2112
4%
704
23%
704
11%
1673
November1st to 15thNight
26%
700
16%
2311
12%
700
33%
700
15%
1645
November16th to endNight
15%
720
9%
2520
7%
720
21%
720
8%
2037
December1st to 15thNight
10%
720
5%
2520
3%
720
13%
720
4%
2212
December16th to endNight
5%
768
3%
2688
0%
768
9%
768
3%
2425

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%12%5%8%5%34446%27%
47414
Night
16%13%5%8%6%34445%27%
46734
Cloud CoverDay
17%12%5%8%6%3445%6%27%
47424
Night
15%12%5%8%6%34445%27%
46738
TransparencyDay
57%410%17%8%
47114
Night
59%49%16%8%1
46552
SeeingDay
24%12%26%20%10%4
5261
Night
25%15%26%21%9%1
14840

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
16%18%10%16%8%2343410%
1513
16th to endDay
11%19%11%18%11%443238%
1728
February1st to 15thDay
16%20%11%14%10%4422210%
1575
16th to endDay
15%18%7%12%10%2433418%
1484
March1st to 15thDay
17%18%8%12%42334421%
1969
16th to endDay
17%14%8%7%5%23445%26%
2112
April1st to 15thDay
20%13%5%5%5%24446%27%
2122
16th to endDay
18%12%34423345%37%
2298
May1st to 15thDay
19%9%36%6%24446%32%
2337
16th to endDay
16%5%35%5%2445%7%39%
2618
June1st to 15thDay
17%7%35%5%3445%8%34%
2520
16th to endDay
16%5%25%435%6%6%9%34%
2520
July1st to 15thDay
12%426%5%35%6%5%9%37%
2520
16th to endDay
13%5%26%5%35%6%7%9%33%
2481
August1st to 15thDay
13%7%25%6%36%6%6%8%33%
2288
16th to endDay
14%6%26%5%25%5%6%8%36%
2200
September1st to 15thDay
20%7%36%5%24446%33%
1966
16th to endDay
18%6%35%43446%7%33%
1793
October1st to 15thDay
22%7%38%6%345%45%27%
1650
16th to endDay
27%15%47%435%33418%
1760
November1st to 15thDay
14%18%45%5%3345%6%28%
1544
16th to endDay
20%25%6%7%5%2433416%
1440
December1st to 15thDay
18%24%13%12%42333212%
1440
16th to endDay
19%23%14%16%4242227%
1536
January1st to 15thNight
18%21%7%16%9%3323210%
2424
16th to endNight
12%20%11%15%12%4422310%
2496
February1st to 15thNight
13%20%7%15%9%46%22213%
2285
16th to endNight
13%14%7%15%11%35%43318%
1985
March1st to 15thNight
16%15%7%11%7%4333420%
1968
16th to endNight
15%11%6%8%6%25%44429%
2112
April1st to 15thNight
19%13%46%424436%30%
1824
16th to endNight
12%10%35%5%2445%7%38%
1671
May1st to 15thNight
18%8%246%35%447%32%
1614
16th to endNight
13%5%36%433448%42%
1495
June1st to 15thNight
13%5%26%435%5%6%7%37%
1440
16th to endNight
13%6%25%5%35%45%8%39%
1440
July1st to 15thNight
8%326%5%335%7%7%45%
1440
16th to endNight
9%4236%26%5%6%8%43%
1685
August1st to 15thNight
9%425%5%345%7%9%44%
1586
16th to endNight
11%4245%245%5%8%43%
1638
September1st to 15thNight
16%5%245%35%45%442%
1663
16th to endNight
19%5%26%4345%47%37%
1837
October1st to 15thNight
19%7%35%5%24446%34%
1980
16th to endNight
28%11%46%435%44422%
2112
November1st to 15thNight
18%13%35%5%3445%6%30%
2311
16th to endNight
18%22%6%8%5%24345%18%
2520
December1st to 15thNight
19%23%12%10%5%2432311%
2520
16th to endNight
18%22%12%15%7%243238%
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
16%18%9%16%9%3344410%
1513
16th to endDay
11%19%11%18%11%443338%
1728
February1st to 15thDay
15%20%10%14%10%4422311%
1575
16th to endDay
15%18%7%12%9%3423418%
1484
March1st to 15thDay
17%18%8%11%5%2333421%
1980
16th to endDay
16%13%9%7%5%23345%27%
2111
April1st to 15thDay
20%13%5%6%424346%27%
2122
16th to endDay
18%12%24433346%37%
2298
May1st to 15thDay
18%9%36%6%35%346%31%
2337
16th to endDay
16%6%25%5%2445%7%38%
2618
June1st to 15thDay
17%7%36%5%2446%8%34%
2520
16th to endDay
16%5%245%35%5%6%9%34%
2520
July1st to 15thDay
11%5%27%5%45%6%6%8%37%
2520
16th to endDay
14%5%26%5%36%6%6%9%32%
2481
August1st to 15thDay
13%7%26%6%36%6%7%8%32%
2288
16th to endDay
14%6%25%5%345%6%8%35%
2200
September1st to 15thDay
21%7%26%5%3445%6%32%
1966
16th to endDay
18%7%36%435%5%5%7%32%
1793
October1st to 15thDay
22%8%36%6%44446%28%
1650
16th to endDay
25%15%47%6%3434419%
1760
November1st to 15thDay
13%18%445%25%35%7%28%
1544
16th to endDay
19%23%6%8%5%2344416%
1440
December1st to 15thDay
18%23%12%12%5%2332312%
1440
16th to endDay
18%23%14%15%6%242227%
1536
January1st to 15thNight
18%19%8%15%9%3333311%
2424
16th to endNight
12%18%11%14%12%4432211%
2496
February1st to 15thNight
13%18%8%14%10%46%33213%
2278
16th to endNight
13%13%7%15%11%45%33318%
1985
March1st to 15thNight
16%14%8%11%6%4333420%
1980
16th to endNight
14%12%6%8%6%34445%29%
2112
April1st to 15thNight
19%13%5%5%324436%30%
1824
16th to endNight
12%10%35%5%3445%7%38%
1671
May1st to 15thNight
18%7%35%5%36%5%47%33%
1613
16th to endNight
12%5%35%5%34348%43%
1495
June1st to 15thNight
12%6%36%4445%6%8%37%
1440
16th to endNight
12%6%25%435%5%6%7%39%
1440
July1st to 15thNight
7%425%6%245%6%8%45%
1440
16th to endNight
9%425%435%47%8%43%
1685
August1st to 15thNight
9%315%5%345%7%10%44%
1586
16th to endNight
11%424435%6%6%8%44%
1638
September1st to 15thNight
15%6%2442445%6%42%
1663
16th to endNight
18%6%36%4245%46%37%
1837
October1st to 15thNight
19%7%26%5%2445%6%35%
1980
16th to endNight
28%11%45%6%24445%22%
2112
November1st to 15thNight
17%13%36%43345%6%30%
2311
16th to endNight
18%21%6%8%5%33335%19%
2520
December1st to 15thNight
19%22%11%11%6%2432311%
2520
16th to endNight
18%21%11%14%8%343328%
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
78%36%8%3
1514
16th to endDay
82%36%5%1
1728
February1st to 15thDay
81%35%6%2
1577
16th to endDay
70%38%12%4
1484
March1st to 15thDay
66%39%14%5%
1980
16th to endDay
58%47%18%8%1
2112
April1st to 15thDay
57%310%18%9%
2122
16th to endDay
49%39%20%14%2
2298
May1st to 15thDay
53%310%21%9%
2337
16th to endDay
44%414%21%12%1
2622
June1st to 15thDay
47%5%13%23%10%1
2520
16th to endDay
44%5%16%21%12%
2520
July1st to 15thDay
42%5%10%23%16%1
2371
16th to endDay
45%5%14%21%10%1
2325
August1st to 15thDay
46%6%13%22%10%
2275
16th to endDay
43%5%12%25%11%1
2200
September1st to 15thDay
50%5%10%21%10%
1966
16th to endDay
48%5%10%22%12%
1793
October1st to 15thDay
57%5%9%15%10%1
1650
16th to endDay
69%311%11%3
1760
November1st to 15thDay
55%411%15%10%3
1544
16th to endDay
71%38%11%41
1440
December1st to 15thDay
79%28%7%1
1440
16th to endDay
85%35%4
1536
January1st to 15thNight
80%26%5%4
2424
16th to endNight
80%26%7%2
2496
February1st to 15thNight
77%37%9%2
2287
16th to endNight
71%28%13%3
1985
March1st to 15thNight
67%36%16%5%
1980
16th to endNight
57%48%16%12%1
2112
April1st to 15thNight
55%310%19%9%
1824
16th to endNight
45%5%11%20%13%4
1671
May1st to 15thNight
50%5%9%22%10%1
1614
16th to endNight
40%6%11%25%13%2
1497
June1st to 15thNight
42%6%12%24%13%
1440
16th to endNight
42%7%11%25%11%1
1440
July1st to 15thNight
35%5%13%25%18%1
1360
16th to endNight
36%5%14%24%15%2
1578
August1st to 15thNight
34%6%15%31%10%2
1575
16th to endNight
35%6%14%26%14%2
1638
September1st to 15thNight
42%5%11%24%14%1
1663
16th to endNight
46%410%21%14%1
1837
October1st to 15thNight
49%410%18%15%
1980
16th to endNight
63%412%13%4
2112
November1st to 15thNight
53%5%11%16%8%4
2311
16th to endNight
69%38%14%4
2520
December1st to 15thNight
80%27%7%2
2520
16th to endNight
82%37%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
36%31%21%5%4
73
16th to endDay
33%36%23%5%1
96
February1st to 15thDay
37%30%31%1
90
16th to endDay
27%14%51%6%
107
March1st to 15thDay
30%22%28%14%4
270
16th to endDay
30%19%28%14%5%1
288
April1st to 15thDay
31%18%25%14%7%2
270
16th to endDay
22%15%30%16%9%5%
270
May1st to 15thDay
33%12%25%20%6%1
288
16th to endDay
19%14%30%22%7%6%
331
June1st to 15thDay
21%8%32%24%11%1
315
16th to endDay
20%11%27%28%9%3
315
July1st to 15thDay
17%6%27%26%15%6%
305
16th to endDay
13%5%29%26%17%6%
326
August1st to 15thDay
16%5%22%26%20%9%
297
16th to endDay
21%416%24%20%13%
268
September1st to 15thDay
18%6%17%25%23%8%
255
16th to endDay
19%7%22%24%18%8%
254
October1st to 15thDay
25%6%25%24%15%2
255
16th to endDay
36%18%27%14%2
272
November1st to 15thDay
25%9%31%25%5%2
132
16th to endDay
38%18%26%15%1
60
December1st to 15thDay
40%30%16%8%13
60
16th to endDay
43%21%31%3
64
January1st to 15thNight
33%25%28%10%2
720
16th to endNight
26%27%30%13%2
768
February1st to 15thNight
29%26%30%11%1
704
16th to endNight
27%23%31%15%2
631
March1st to 15thNight
32%18%29%15%3
720
16th to endNight
24%16%30%20%6%1
768
April1st to 15thNight
30%14%31%17%5%
718
16th to endNight
20%11%33%24%7%1
591
May1st to 15thNight
21%9%25%32%10%
534
16th to endNight
16%8%29%28%14%2
375
June1st to 15thNight
15%6%31%30%16%
360
16th to endNight
16%5%28%36%12%
360
July1st to 15thNight
9%223%40%20%2
340
16th to endNight
12%322%35%24%1
547
August1st to 15thNight
11%317%41%21%3
527
16th to endNight
14%318%30%29%4
588
September1st to 15thNight
20%6%17%27%23%3
660
16th to endNight
22%6%21%23%21%4
657
October1st to 15thNight
26%10%22%25%12%2
660
16th to endNight
38%13%26%18%3
704
November1st to 15thNight
29%13%26%23%5%1
700
16th to endNight
35%21%24%11%6%
720
December1st to 15thNight
36%26%23%10%2
720
16th to endNight
34%24%29%9%1
768
Page generated at 2017-08-13 14:16:46. Version ac04

Copyright 2017 A. Danko


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