Pineland Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pineland Observatory clear sky chart from 2005-11-05 to 2017-09-24.

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
66%
16004
19%
47058
17%
15968
69%
15968
30%
29612

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
59%
716
18%
2327
17%
716
63%
716
28%
1410
January16th to endNight
56%
768
25%
2376
21%
768
62%
768
31%
1419
February1st to 15thNight
52%
699
23%
2107
18%
699
59%
699
33%
1276
February16th to endNight
61%
631
27%
1830
20%
631
67%
631
40%
1027
March1st to 15thNight
63%
720
30%
1980
21%
720
71%
720
46%
1086
March16th to endNight
66%
768
28%
2112
23%
768
68%
768
43%
1191
April1st to 15thNight
71%
718
23%
1976
20%
718
74%
718
46%
1065
April16th to endNight
65%
720
26%
1887
19%
720
69%
720
43%
1109
May1st to 15thNight
80%
596
25%
1676
21%
596
82%
596
47%
921
May16th to endNight
78%
561
19%
1683
17%
561
79%
561
34%
1025
June1st to 15thNight
70%
540
8%
1620
7%
540
70%
540
20%
1175
June16th to endNight
76%
540
6%
1620
6%
540
76%
540
21%
1190
July1st to 15thNight
74%
510
5%
1530
5%
510
74%
510
19%
1158
July16th to endNight
78%
564
6%
1595
6%
531
79%
531
23%
1145
August1st to 15thNight
72%
539
5%
1689
6%
536
72%
536
22%
1195
August16th to endNight
68%
729
6%
2066
6%
729
68%
729
17%
1548
September1st to 15thNight
65%
720
6%
1980
6%
720
65%
720
17%
1495
September16th to endNight
63%
693
7%
1914
7%
693
63%
693
17%
1474
October1st to 15thNight
70%
660
23%
1848
23%
660
72%
660
33%
1147
October16th to endNight
57%
704
23%
2112
22%
704
61%
704
29%
1314
November1st to 15thNight
64%
700
29%
2101
27%
700
69%
700
38%
1190
November16th to endNight
61%
720
28%
2193
25%
720
66%
720
34%
1274
December1st to 15thNight
61%
720
24%
2340
24%
720
64%
720
30%
1390
December16th to endNight
65%
768
24%
2496
25%
768
68%
768
35%
1388

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
6%425%5%36%6%7%10%41%
47852
Night
6%425%5%35%5%7%9%43%
47262
TransparencyDay
35%10%18%19%12%4
47553
Night
33%9%17%19%14%4
47065
SeeingDay
8%19%21%29%29%
5855
Night
8%112%32%31%12%
16016

By Month

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
9%5%35%3245%6%9%44%
1611
16th to endDay
9%414425%5%5%8%48%
1845
February1st to 15thDay
9%42432335%7%52%
1750
16th to endDay
5%4134235%5%9%55%
1641
March1st to 15thDay
3213325%46%10%58%
1980
16th to endDay
5%314425%5%5%7%53%
2111
April1st to 15thDay
5%11342446%10%54%
1972
16th to endDay
5%31442446%9%54%
2072
May1st to 15thDay
31123135%6%10%60%
2282
16th to endDay
5%3245%36%6%7%11%42%
2431
June1st to 15thDay
10%6%36%6%36%6%8%12%27%
2340
16th to endDay
6%5%25%6%5%7%8%10%13%27%
2340
July1st to 15thDay
6%437%9%5%9%9%9%12%21%
2340
16th to endDay
6%426%8%5%9%11%10%14%20%
2465
August1st to 15thDay
45%27%8%49%8%10%12%26%
2256
16th to endDay
8%5%36%8%5%8%8%8%11%25%
2123
September1st to 15thDay
7%437%8%5%7%6%10%12%25%
1980
16th to endDay
9%6%37%8%5%8%8%7%10%25%
1905
October1st to 15thDay
6%425%6%35%5%7%9%41%
1779
16th to endDay
9%414435%5%5%7%46%
1760
November1st to 15thDay
6%31442445%8%53%
1757
16th to endDay
6%32342446%9%50%
1764
December1st to 15thDay
8%435%435%5%6%8%44%
1620
16th to endDay
5%415%4245%8%9%48%
1728
January1st to 15thNight
7%5%25%5%35%5%7%9%41%
2327
16th to endNight
9%4245%35%5%6%8%44%
2376
February1st to 15thNight
9%5%245%3345%5%49%
2103
16th to endNight
5%313436%35%10%51%
1830
March1st to 15thNight
421242446%10%55%
1980
16th to endNight
32144335%6%9%54%
2112
April1st to 15thNight
42134235%5%10%55%
1976
16th to endNight
44145%25%45%9%52%
1887
May1st to 15thNight
21133245%6%9%57%
1676
16th to endNight
5%4145%3447%8%48%
1682
June1st to 15thNight
10%5%35%6%46%8%9%10%30%
1620
16th to endNight
5%327%6%5%7%6%11%12%30%
1620
July1st to 15thNight
5%436%7%5%6%9%9%12%28%
1620
16th to endNight
4325%6%47%9%11%13%31%
1703
August1st to 15thNight
5%6%25%7%46%7%8%12%32%
1700
16th to endNight
9%5%26%7%5%6%7%9%13%28%
2066
September1st to 15thNight
7%6%27%7%5%7%7%9%12%26%
1980
16th to endNight
9%7%37%6%37%7%9%11%23%
1914
October1st to 15thNight
5%5%146%25%6%7%9%45%
1848
16th to endNight
10%5%25%5%345%47%43%
2112
November1st to 15thNight
6%425%4145%48%52%
2101
16th to endNight
7%3245%2345%8%50%
2193
December1st to 15thNight
7%426%4345%5%8%46%
2340
16th to endNight
5%4244345%6%9%49%
2496

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
34%6%14%23%16%3
1612
16th to endDay
32%5%10%24%19%6%
1845
February1st to 15thDay
30%5%9%22%19%11%
1752
16th to endDay
25%6%15%22%22%7%
1641
March1st to 15thDay
21%5%14%28%22%6%
1980
16th to endDay
27%5%13%25%20%8%
2112
April1st to 15thDay
23%6%20%25%18%5%
1972
16th to endDay
27%5%14%23%24%3
2072
May1st to 15thDay
18%7%17%30%20%5%
2282
16th to endDay
33%9%19%25%11%
2435
June1st to 15thDay
47%10%24%13%3
2340
16th to endDay
42%16%25%13%2
2340
July1st to 15thDay
49%18%22%7%1
2201
16th to endDay
45%18%24%9%
2310
August1st to 15thDay
44%18%28%8%
2243
16th to endDay
49%16%24%8%
2123
September1st to 15thDay
46%16%25%9%1
1980
16th to endDay
51%13%20%11%3
1905
October1st to 15thDay
36%8%15%19%16%4
1779
16th to endDay
33%7%12%17%19%9%
1760
November1st to 15thDay
27%5%11%24%21%9%
1757
16th to endDay
29%6%12%21%18%11%
1764
December1st to 15thDay
36%6%14%22%15%5%
1620
16th to endDay
29%7%14%24%18%5%
1728
January1st to 15thNight
36%6%14%25%13%3
2327
16th to endNight
34%5%11%22%19%5%
2376
February1st to 15thNight
34%5%8%19%20%11%
2112
16th to endNight
26%6%13%23%21%7%
1830
March1st to 15thNight
23%5%13%30%21%5%
1980
16th to endNight
25%6%13%27%20%6%
2112
April1st to 15thNight
22%5%18%30%17%4
1976
16th to endNight
28%5%13%23%25%4
1887
May1st to 15thNight
21%7%17%27%20%5%
1677
16th to endNight
31%8%18%25%15%
1684
June1st to 15thNight
43%14%23%14%4
1620
16th to endNight
39%18%26%12%3
1620
July1st to 15thNight
42%19%29%7%1
1530
16th to endNight
36%18%32%12%
1595
August1st to 15thNight
38%16%34%9%
1689
16th to endNight
44%17%27%9%
2066
September1st to 15thNight
45%16%26%9%1
1980
16th to endNight
48%15%21%10%3
1914
October1st to 15thNight
30%10%18%16%18%4
1848
16th to endNight
37%5%11%16%20%7%
2112
November1st to 15thNight
29%410%23%23%8%
2101
16th to endNight
31%5%10%20%19%10%
2193
December1st to 15thNight
34%6%12%24%16%4
2340
16th to endNight
30%5%15%22%21%5%
2496

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
16%6%24%33%15%3
90
16th to endDay
15%10%29%29%13%2
96
February1st to 15thDay
36%25%31%23%10%
90
16th to endDay
9%223%42%19%1
142
March1st to 15thDay
4121%41%27%3
270
16th to endDay
6%221%36%28%4
288
April1st to 15thDay
4216%36%34%4
270
16th to endDay
8%18%40%34%7%
270
May1st to 15thDay
5%7%29%37%19%
288
16th to endDay
6%5%18%34%33%
331
June1st to 15thDay
17%15%12%25%36%
315
16th to endDay
5%115%23%62%
315
July1st to 15thDay
5%1222%66%
305
16th to endDay
9%17%23%57%
326
August1st to 15thDay
7%15%27%57%
313
16th to endDay
13%46%24%50%
332
September1st to 15thDay
8%148%27%49%
315
16th to endDay
9%128%39%40%
287
October1st to 15thDay
8%7%27%37%18%
255
16th to endDay
12%14%31%30%11%
272
November1st to 15thDay
7%212%30%32%15%
265
16th to endDay
7%120%34%32%4
234
December1st to 15thDay
12%123%37%24%1
90
16th to endDay
3212%31%41%9%
96
January1st to 15thNight
10%418%38%26%1
720
16th to endNight
9%5%21%42%19%1
768
February1st to 15thNight
11%324%43%16%
704
16th to endNight
7%124%45%20%
631
March1st to 15thNight
6%123%42%23%1
720
16th to endNight
5%118%48%23%1
768
April1st to 15thNight
4215%48%26%2
718
16th to endNight
6%117%44%27%2
720
May1st to 15thNight
38%42%40%4
597
16th to endNight
5%1435%44%8%
563
June1st to 15thNight
12%2412%48%19%
540
16th to endNight
5%110%41%41%
540
July1st to 15thNight
6%16%39%46%
510
16th to endNight
5%15%34%51%
564
August1st to 15thNight
8%16%41%41%
539
16th to endNight
11%139%38%35%
729
September1st to 15thNight
9%1413%40%31%
720
16th to endNight
13%317%42%21%
693
October1st to 15thNight
8%17%34%38%9%
660
16th to endNight
13%115%33%28%7%
704
November1st to 15thNight
8%116%42%27%4
700
16th to endNight
8%218%39%28%2
720
December1st to 15thNight
10%217%40%26%1
720
16th to endNight
7%118%37%31%2
768
Page generated at 2017-09-25 09:02:29. Version ac04

Copyright 2017 A. Danko


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