Pine Islands
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pine Islands clear sky chart from 2005-11-05 to

2017-09-12
.

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
31%
14952
11%
46634
8%
14917
35%
14917
15%
34937

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%
859
3%
2632
1%
857
15%
857
5%
2322
January16th to endNight
20%
768
7%
2496
5%
768
23%
768
8%
2077
February1st to 15thNight
19%
702
7%
2287
3%
701
23%
701
7%
1902
February16th to endNight
25%
631
8%
2018
4%
631
30%
631
11%
1568
March1st to 15thNight
24%
720
12%
1995
6%
720
29%
720
16%
1500
March16th to endNight
35%
768
19%
2112
11%
768
41%
768
24%
1454
April1st to 15thNight
28%
700
14%
1809
6%
700
32%
700
20%
1334
April16th to endNight
37%
540
18%
1620
11%
540
43%
540
22%
1127
May1st to 15thNight
45%
480
15%
1560
14%
480
48%
480
21%
1043
May16th to endNight
46%
374
14%
1497
13%
374
55%
374
22%
879
June1st to 15thNight
50%
360
11%
1341
14%
360
54%
360
21%
846
June16th to endNight
51%
360
12%
1260
13%
360
55%
360
24%
774
July1st to 15thNight
59%
340
16%
1190
20%
340
62%
340
32%
653
July16th to endNight
53%
470
15%
1497
16%
441
53%
441
27%
899
August1st to 15thNight
59%
539
15%
1609
13%
536
61%
536
29%
1003
August16th to endNight
54%
597
18%
1743
11%
597
58%
597
29%
1104
September1st to 15thNight
48%
707
14%
1793
8%
707
50%
707
28%
1240
September16th to endNight
50%
657
17%
1826
12%
657
53%
657
25%
1267
October1st to 15thNight
31%
660
13%
1980
10%
660
36%
660
15%
1496
October16th to endNight
19%
704
9%
2123
4%
704
25%
704
9%
1739
November1st to 15thNight
25%
700
13%
2410
11%
700
30%
700
12%
1831
November16th to endNight
15%
720
7%
2520
4%
720
20%
720
6%
2115
December1st to 15thNight
10%
720
2%
2520
1%
720
12%
720
3%
2286
December16th to endNight
11%
876
5%
2796
2%
876
13%
876
4%
2478

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%36%5%3445%6%33%
48022
Night
18%11%47%6%34445%28%
46801
Cloud CoverDay
17%9%36%5%2445%6%33%
48032
Night
19%11%47%5%34446%29%
46805
TransparencyDay
50%7%12%19%9%
47708
Night
57%5%11%16%9%
46634
SeeingDay
21%7%26%26%13%4
5705
Night
24%9%26%25%12%1
14958

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
21%16%6%12%5%35%5%5%413%
1300
16th to endDay
16%17%8%10%9%35%335%15%
1728
February1st to 15thDay
13%15%7%12%7%5%444420%
1575
16th to endDay
14%15%7%9%7%3443424%
1452
March1st to 15thDay
15%10%45%6%45%445%33%
1954
16th to endDay
14%7%3442445%6%41%
2112
April1st to 15thDay
21%8%35%424345%34%
2147
16th to endDay
19%6%245%2435%6%39%
2340
May1st to 15thDay
18%6%345%24446%38%
2391
16th to endDay
13%4244245%6%7%43%
2618
June1st to 15thDay
16%5%245%3436%8%38%
2616
16th to endDay
13%6%344345%6%9%39%
2700
July1st to 15thDay
10%41442446%8%48%
2700
16th to endDay
10%425%42445%9%45%
2565
August1st to 15thDay
11%5%1443345%8%46%
2340
16th to endDay
12%425%5%3445%8%43%
2447
September1st to 15thDay
16%6%25%5%2345%6%40%
2085
16th to endDay
17%5%245%34446%40%
1804
October1st to 15thDay
26%7%26%5%33335%32%
1650
16th to endDay
33%10%48%5%2343418%
1746
November1st to 15thDay
23%12%5%6%6%34346%22%
1447
16th to endDay
27%15%6%7%8%35%44412%
1440
December1st to 15thDay
22%24%8%8%7%35%4338%
1440
16th to endDay
21%20%7%10%7%45%435%8%
1425
January1st to 15thNight
22%17%7%13%6%3432412%
2632
16th to endNight
17%16%7%11%8%3435%5%14%
2496
February1st to 15thNight
13%18%8%12%7%35%345%15%
2285
16th to endNight
17%12%6%10%5%45%445%24%
2018
March1st to 15thNight
17%12%46%7%34346%30%
1983
16th to endNight
14%9%47%5%23335%40%
2112
April1st to 15thNight
22%9%35%42335%434%
1809
16th to endNight
17%7%35%5%34446%37%
1620
May1st to 15thNight
18%6%25%5%3445%7%36%
1560
16th to endNight
13%4245%34448%43%
1495
June1st to 15thNight
14%5%345%445%5%8%39%
1341
16th to endNight
13%5%2434446%8%40%
1260
July1st to 15thNight
9%424424346%52%
1260
16th to endNight
9%5%25%4345%5%8%45%
1599
August1st to 15thNight
10%5%25%425%5%48%46%
1620
16th to endNight
13%425%42445%6%45%
1743
September1st to 15thNight
15%5%245%3445%7%39%
1793
16th to endNight
18%435%5%25%446%39%
1826
October1st to 15thNight
25%8%36%5%23445%29%
1980
16th to endNight
33%11%46%5%23445%18%
2123
November1st to 15thNight
22%14%36%5%3435%5%24%
2410
16th to endNight
27%17%6%8%6%2333414%
2520
December1st to 15thNight
23%26%8%10%6%343337%
2520
16th to endNight
23%20%8%10%7%3334310%
2796

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
22%16%6%12%5%25%345%16%
1300
16th to endDay
15%17%9%10%6%34435%17%
1728
February1st to 15thDay
14%15%8%12%6%45%33421%
1575
16th to endDay
16%16%6%9%6%25%5%3324%
1452
March1st to 15thDay
16%11%46%445%346%32%
1965
16th to endDay
14%7%3443445%6%41%
2111
April1st to 15thDay
22%9%35%424345%34%
2147
16th to endDay
20%6%34424346%39%
2340
May1st to 15thDay
18%7%245%24446%38%
2391
16th to endDay
14%4234245%6%8%42%
2618
June1st to 15thDay
17%5%24435%46%7%37%
2616
16th to endDay
14%6%25%4245%6%9%38%
2700
July1st to 15thDay
11%42442436%7%47%
2700
16th to endDay
12%4245%245%5%8%44%
2565
August1st to 15thDay
12%5%25%5%24448%45%
2340
16th to endDay
14%416%5%3445%6%42%
2447
September1st to 15thDay
16%6%25%6%2335%7%40%
2085
16th to endDay
17%6%25%435%45%5%39%
1804
October1st to 15thDay
26%7%35%5%23336%31%
1650
16th to endDay
34%8%36%6%3442420%
1746
November1st to 15thDay
24%11%36%5%35%447%23%
1447
16th to endDay
27%15%5%7%5%35%5%45%15%
1440
December1st to 15thDay
22%24%7%8%42345%5%10%
1440
16th to endDay
22%20%7%9%6%34335%12%
1425
January1st to 15thNight
22%17%6%11%7%35%42414%
2632
16th to endNight
16%16%8%10%7%24445%18%
2496
February1st to 15thNight
13%19%7%10%7%35%44418%
2278
16th to endNight
17%12%6%8%6%35%44425%
2018
March1st to 15thNight
17%10%46%7%4434430%
1995
16th to endNight
14%9%47%42333441%
2112
April1st to 15thNight
23%10%35%423345%33%
1809
16th to endNight
17%8%35%5%33446%36%
1620
May1st to 15thNight
18%6%26%424447%37%
1559
16th to endNight
13%3245%35%45%9%42%
1495
June1st to 15thNight
15%5%25%5%3446%7%39%
1341
16th to endNight
13%5%25%43446%10%40%
1260
July1st to 15thNight
9%334424446%52%
1260
16th to endNight
10%425%5%3446%7%45%
1599
August1st to 15thNight
10%425%4345%5%7%46%
1620
16th to endNight
12%425%42445%6%45%
1743
September1st to 15thNight
15%4245%4446%7%40%
1793
16th to endNight
17%5%145%34447%40%
1826
October1st to 15thNight
25%7%36%5%245%4431%
1980
16th to endNight
33%9%37%5%23335%22%
2123
November1st to 15thNight
22%12%45%43445%6%26%
2410
16th to endNight
27%15%5%7%5%24445%16%
2520
December1st to 15thNight
22%26%7%9%5%243449%
2520
16th to endNight
22%21%7%10%7%3333413%
2796

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
72%8%9%8%1
1301
16th to endDay
72%48%9%4
1728
February1st to 15thDay
67%8%8%12%3
1577
16th to endDay
63%6%10%13%6%
1452
March1st to 15thDay
52%5%16%16%7%
1965
16th to endDay
42%6%13%19%16%2
2112
April1st to 15thDay
51%49%21%11%1
2147
16th to endDay
46%5%9%22%14%2
2340
May1st to 15thDay
45%5%11%21%13%1
2391
16th to endDay
36%9%14%22%14%2
2622
June1st to 15thDay
43%7%12%24%11%
2616
16th to endDay
39%8%16%21%13%
2700
July1st to 15thDay
30%9%15%28%15%1
2541
16th to endDay
37%7%13%28%12%
2405
August1st to 15thDay
35%8%17%24%13%
2327
16th to endDay
38%9%14%25%9%
2447
September1st to 15thDay
42%8%14%24%8%
2085
16th to endDay
44%8%12%26%8%
1804
October1st to 15thDay
55%5%10%17%10%
1650
16th to endDay
68%6%10%9%4
1746
November1st to 15thDay
61%6%12%11%6%
1447
16th to endDay
74%5%11%5%2
1440
December1st to 15thDay
79%5%8%5%1
1440
16th to endDay
77%5%9%5%1
1425
January1st to 15thNight
76%6%8%43
2632
16th to endNight
69%6%10%8%4
2496
February1st to 15thNight
70%6%8%11%3
2287
16th to endNight
62%5%12%13%6%
2018
March1st to 15thNight
56%412%17%7%
1995
16th to endNight
46%410%19%16%2
2112
April1st to 15thNight
52%48%19%13%1
1809
16th to endNight
48%5%8%17%18%2
1620
May1st to 15thNight
46%6%9%18%16%3
1560
16th to endNight
38%7%13%24%15%1
1497
June1st to 15thNight
43%5%11%23%14%
1341
16th to endNight
39%6%13%26%13%
1260
July1st to 15thNight
31%5%12%27%20%1
1190
16th to endNight
37%6%13%28%14%
1497
August1st to 15thNight
35%7%16%25%13%
1609
16th to endNight
38%6%15%26%13%
1743
September1st to 15thNight
41%7%15%23%10%
1793
16th to endNight
44%7%13%26%9%
1826
October1st to 15thNight
57%6%9%16%10%
1980
16th to endNight
67%5%9%12%4
2123
November1st to 15thNight
58%6%12%14%6%
2410
16th to endNight
72%5%10%9%2
2520
December1st to 15thNight
81%5%7%31
2520
16th to endNight
78%47%5%2
2796

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%14%45%14%3
62
16th to endDay
40%9%25%18%6%
96
February1st to 15thDay
28%20%37%13%
90
16th to endDay
30%17%35%16%
81
March1st to 15thDay
24%10%30%26%6%
255
16th to endDay
20%7%35%21%11%2
288
April1st to 15thDay
24%10%31%20%10%2
270
16th to endDay
24%9%30%19%11%3
270
May1st to 15thDay
23%7%25%23%13%5%
288
16th to endDay
17%429%29%13%4
331
June1st to 15thDay
21%8%23%28%16%2
411
16th to endDay
16%427%35%14%1
495
July1st to 15thDay
12%6%24%33%18%5%
475
16th to endDay
15%425%30%18%5%
331
August1st to 15thDay
15%118%34%19%9%
313
16th to endDay
21%316%30%18%9%
332
September1st to 15thDay
16%325%24%20%10%
299
16th to endDay
20%320%31%18%5%
254
October1st to 15thDay
28%8%26%21%11%3
255
16th to endDay
34%15%26%17%5%
258
November1st to 15thDay
22%13%29%25%8%
67
16th to endDay
28%16%38%16%
60
December1st to 15thDay
31%25%26%13%11
60
16th to endDay
35%34%23%6%
64
January1st to 15thNight
31%16%29%17%4
862
16th to endNight
25%10%30%23%9%1
768
February1st to 15thNight
23%14%32%23%5%
704
16th to endNight
24%10%30%25%9%
631
March1st to 15thNight
22%13%31%26%5%
720
16th to endNight
18%5%32%29%12%1
768
April1st to 15thNight
27%8%29%28%6%
700
16th to endNight
21%7%26%28%15%
540
May1st to 15thNight
20%418%38%15%2
480
16th to endNight
14%427%33%19%
375
June1st to 15thNight
16%418%41%16%1
360
16th to endNight
17%221%35%22%1
360
July1st to 15thNight
10%220%37%25%3
340
16th to endNight
11%223%33%26%2
470
August1st to 15thNight
12%216%36%27%4
539
16th to endNight
14%221%28%28%4
597
September1st to 15thNight
17%5%21%28%20%6%
707
16th to endNight
18%7%19%30%19%5%
657
October1st to 15thNight
27%9%25%22%12%1
660
16th to endNight
37%13%24%19%4
704
November1st to 15thNight
28%12%27%19%11%
700
16th to endNight
35%12%29%17%4
720
December1st to 15thNight
36%19%28%12%3
720
16th to endNight
32%14%30%17%3
876
Page generated at 2017-09-13 07:39:06. Version ac04

Copyright 2017 A. Danko


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