Little Point Sable
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Little Point Sable 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
39%
16014
12%
46772
9%
15972
41%
15972
17%
34838

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%
900
3%
2506
1%
895
14%
895
5%
2262
January16th to endNight
15%
960
3%
2688
2%
960
16%
960
5%
2437
February1st to 15thNight
19%
770
5%
2241
2%
770
22%
770
8%
1931
February16th to endNight
24%
631
7%
1893
4%
631
27%
631
9%
1582
March1st to 15thNight
34%
720
12%
2160
8%
720
38%
720
17%
1580
March16th to endNight
40%
687
17%
2034
13%
687
45%
687
21%
1425
April1st to 15thNight
36%
539
14%
1797
11%
539
41%
539
18%
1263
April16th to endNight
47%
540
19%
1662
15%
540
52%
540
23%
1109
May1st to 15thNight
51%
540
14%
1614
12%
540
54%
540
23%
1120
May16th to endNight
57%
562
15%
1498
11%
561
61%
561
31%
991
June1st to 15thNight
60%
540
13%
1440
10%
540
61%
540
34%
918
June16th to endNight
67%
540
14%
1440
10%
540
69%
540
33%
916
July1st to 15thNight
74%
510
17%
1360
13%
510
75%
510
42%
784
July16th to endNight
71%
564
16%
1417
14%
531
72%
531
38%
883
August1st to 15thNight
73%
539
22%
1542
19%
536
74%
536
39%
880
August16th to endNight
65%
573
20%
1854
20%
573
67%
573
30%
1105
September1st to 15thNight
61%
568
20%
1805
21%
568
63%
568
29%
1100
September16th to endNight
59%
657
20%
1815
16%
657
61%
657
31%
1168
October1st to 15thNight
48%
660
18%
1864
14%
660
52%
660
25%
1281
October16th to endNight
26%
704
9%
2288
6%
704
30%
704
13%
1723
November1st to 15thNight
33%
700
15%
2276
14%
700
37%
700
15%
1650
November16th to endNight
20%
750
6%
2370
5%
750
22%
750
8%
1979
December1st to 15thNight
12%
900
2%
2520
1%
900
13%
900
4%
2309
December16th to endNight
12%
960
4%
2688
1%
960
15%
960
5%
2442

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%47%5%34446%35%
47897
Night
15%11%5%7%6%34346%30%
46940
Cloud CoverDay
14%9%46%5%24346%35%
47906
Night
16%11%5%7%6%34345%31%
46945
TransparencyDay
48%6%12%20%10%1
47583
Night
54%6%11%17%9%1
46772
SeeingDay
16%319%32%22%5%
6004
Night
20%7%23%30%15%2
16018

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
17%18%9%14%9%5%433310%
1432
16th to endDay
14%17%13%16%10%5%42238%
1536
February1st to 15thDay
13%15%8%12%12%44445%13%
1618
16th to endDay
13%14%9%13%9%5%5%33416%
1580
March1st to 15thDay
13%10%5%10%7%35%447%28%
1790
16th to endDay
15%8%47%6%3435%7%34%
2199
April1st to 15thDay
20%9%35%425%446%33%
2151
16th to endDay
17%7%25%6%34446%37%
2298
May1st to 15thDay
15%5%35%5%34448%38%
2334
16th to endDay
10%4244345%6%8%46%
2617
June1st to 15thDay
12%5%25%5%34448%43%
2520
16th to endDay
9%314425%5%5%9%48%
2520
July1st to 15thDay
6%41342345%8%54%
2520
16th to endDay
7%323425%47%8%51%
2655
August1st to 15thDay
6%32433446%10%49%
2407
16th to endDay
13%41442335%6%50%
2346
September1st to 15thDay
14%6%13423437%47%
2062
16th to endDay
12%5%25%435%45%8%41%
1815
October1st to 15thDay
19%7%25%32345%6%37%
1766
16th to endDay
24%9%37%5%34346%25%
1584
November1st to 15thDay
18%12%47%423346%31%
1582
16th to endDay
22%22%6%9%5%13235%15%
1589
December1st to 15thDay
18%23%14%13%7%2212210%
1440
16th to endDay
20%24%11%11%8%233229%
1536
January1st to 15thNight
20%19%8%13%10%3322212%
2506
16th to endNight
13%20%11%13%11%45%23310%
2688
February1st to 15thNight
12%16%9%14%9%5%423416%
2239
16th to endNight
15%15%7%11%9%5%4345%17%
1893
March1st to 15thNight
13%9%5%8%6%2445%6%32%
2147
16th to endNight
15%8%35%6%3445%7%34%
2034
April1st to 15thNight
19%10%45%42436%6%31%
1797
16th to endNight
18%6%34424446%40%
1662
May1st to 15thNight
16%6%25%7%3445%7%34%
1614
16th to endNight
9%6%345%3445%9%42%
1496
June1st to 15thNight
11%426%43435%7%46%
1440
16th to endNight
9%5%24425%5%6%9%45%
1440
July1st to 15thNight
7%2134245%6%9%52%
1440
16th to endNight
6%3245%335%6%9%50%
1513
August1st to 15thNight
6%3143335%5%8%52%
1551
16th to endNight
12%423434446%49%
1854
September1st to 15thNight
14%5%23424446%48%
1805
16th to endNight
13%424433447%47%
1815
October1st to 15thNight
20%6%25%414247%40%
1864
16th to endNight
25%10%36%5%23345%28%
2288
November1st to 15thNight
18%15%45%334335%32%
2276
16th to endNight
21%22%5%8%5%2333417%
2370
December1st to 15thNight
22%23%11%12%5%232229%
2520
16th to endNight
21%23%9%11%6%2333310%
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
17%17%10%13%8%5%5%32311%
1432
16th to endDay
14%17%14%14%11%5%42339%
1536
February1st to 15thDay
13%14%9%12%12%35%34413%
1618
16th to endDay
13%14%9%13%9%46%34416%
1580
March1st to 15thDay
14%10%5%9%6%34446%29%
1800
16th to endDay
15%9%47%5%3435%7%33%
2198
April1st to 15thDay
20%10%44423436%33%
2151
16th to endDay
17%8%245%3445%6%37%
2298
May1st to 15thDay
16%6%35%424448%38%
2334
16th to endDay
10%42442446%8%46%
2617
June1st to 15thDay
13%5%25%42435%8%43%
2520
16th to endDay
10%323425%45%8%48%
2520
July1st to 15thDay
8%31342345%8%54%
2520
16th to endDay
8%323325%46%8%51%
2655
August1st to 15thDay
7%32432447%9%50%
2407
16th to endDay
13%424324346%49%
2346
September1st to 15thDay
15%5%13413347%47%
2062
16th to endDay
12%6%25%4245%49%41%
1815
October1st to 15thDay
19%8%24423446%37%
1766
16th to endDay
25%10%36%5%35%346%25%
1584
November1st to 15thDay
18%12%46%5%24346%31%
1582
16th to endDay
22%23%6%9%5%23235%15%
1589
December1st to 15thDay
18%22%14%14%7%2211211%
1440
16th to endDay
20%24%11%11%7%322239%
1536
January1st to 15thNight
21%19%9%12%9%3322213%
2506
16th to endNight
12%20%10%13%11%45%33311%
2688
February1st to 15thNight
12%16%9%14%9%5%423417%
2232
16th to endNight
15%15%7%11%9%44345%18%
1893
March1st to 15thNight
14%9%5%8%5%23446%33%
2160
16th to endNight
16%8%35%5%3445%6%35%
2034
April1st to 15thNight
19%10%45%43426%6%31%
1797
16th to endNight
19%6%25%424346%40%
1662
May1st to 15thNight
17%5%26%5%4445%6%36%
1613
16th to endNight
9%6%35%43445%9%42%
1496
June1st to 15thNight
11%425%43446%6%46%
1440
16th to endNight
9%42443446%10%44%
1440
July1st to 15thNight
7%1134245%6%9%53%
1440
16th to endNight
6%315%42447%7%51%
1513
August1st to 15thNight
6%3243335%5%8%53%
1551
16th to endNight
13%41343445%6%49%
1854
September1st to 15thNight
14%5%13424346%49%
1805
16th to endNight
14%314434346%48%
1815
October1st to 15thNight
20%6%24423336%41%
1864
16th to endNight
25%9%37%5%23445%28%
2288
November1st to 15thNight
18%15%5%5%434335%32%
2276
16th to endNight
21%22%6%8%5%2344417%
2370
December1st to 15thNight
22%23%11%11%6%222339%
2520
16th to endNight
21%23%9%11%7%1333311%
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
80%5%6%7%
1433
16th to endDay
83%5%5%41
1536
February1st to 15thDay
72%8%8%9%
1620
16th to endDay
72%6%9%8%3
1580
March1st to 15thDay
55%8%14%14%6%1
1800
16th to endDay
47%6%16%21%6%1
2199
April1st to 15thDay
51%5%11%20%11%
2151
16th to endDay
46%5%13%18%13%3
2298
May1st to 15thDay
44%6%12%23%11%1
2334
16th to endDay
34%7%15%27%13%1
2621
June1st to 15thDay
39%6%12%24%15%
2520
16th to endDay
31%9%17%24%15%1
2520
July1st to 15thDay
27%6%14%31%17%2
2371
16th to endDay
29%8%14%28%16%3
2488
August1st to 15thDay
28%8%18%30%13%1
2392
16th to endDay
34%5%14%27%15%1
2346
September1st to 15thDay
35%6%13%27%13%1
2062
16th to endDay
38%7%16%25%10%
1815
October1st to 15thDay
45%7%12%23%10%
1766
16th to endDay
58%6%16%13%4
1584
November1st to 15thDay
55%5%11%19%8%
1582
16th to endDay
73%411%8%2
1589
December1st to 15thDay
83%36%41
1440
16th to endDay
82%47%41
1536
January1st to 15thNight
79%45%7%2
2506
16th to endNight
79%5%8%41
2688
February1st to 15thNight
73%5%6%10%3
2241
16th to endNight
69%5%10%9%4
1893
March1st to 15thNight
51%7%13%16%9%1
2160
16th to endNight
47%7%12%22%9%1
2034
April1st to 15thNight
52%5%9%17%14%1
1797
16th to endNight
44%6%9%20%14%4
1662
May1st to 15thNight
47%5%12%20%12%1
1614
16th to endNight
38%6%12%24%14%3
1498
June1st to 15thNight
36%5%13%26%15%1
1440
16th to endNight
32%9%16%23%15%2
1440
July1st to 15thNight
25%7%13%29%20%3
1360
16th to endNight
29%9%15%25%17%3
1417
August1st to 15thNight
27%6%14%34%15%1
1542
16th to endNight
34%7%10%26%19%2
1854
September1st to 15thNight
36%6%11%26%17%1
1805
16th to endNight
37%6%13%31%10%
1815
October1st to 15thNight
45%5%10%25%12%
1864
16th to endNight
57%7%14%14%5%
2288
November1st to 15thNight
55%5%11%16%10%1
2276
16th to endNight
70%5%12%8%2
2370
December1st to 15thNight
82%46%42
2520
16th to endNight
80%5%7%42
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%6%41%26%3
90
16th to endDay
31%223%32%9%1
96
February1st to 15thDay
11%21%42%20%5%
90
16th to endDay
25%7%30%27%7%1
81
March1st to 15thDay
30%10%25%25%8%
90
16th to endDay
27%5%24%25%14%2
285
April1st to 15thDay
28%427%28%10%1
270
16th to endDay
22%321%33%13%4
270
May1st to 15thDay
21%320%32%16%4
291
16th to endDay
13%220%34%22%6%
517
June1st to 15thDay
13%216%38%24%3
495
16th to endDay
10%118%38%24%5%
495
July1st to 15thDay
8%113%36%32%8%
475
16th to endDay
7%111%40%30%7%
515
August1st to 15thDay
8%29%36%28%13%
380
16th to endDay
18%114%24%31%9%
332
September1st to 15thDay
14%212%30%29%10%
299
16th to endDay
13%418%25%29%9%
254
October1st to 15thDay
19%221%26%23%5%
217
16th to endDay
25%131%36%6%
96
November1st to 15thDay
15%6%21%36%16%3
90
16th to endDay
36%5%34%16%6%
90
December1st to 15thDay
33%13%36%11%5%
90
16th to endDay
34%16%38%10%
96
January1st to 15thNight
29%11%32%20%6%
900
16th to endNight
20%9%37%27%5%
960
February1st to 15thNight
18%13%33%28%6%
773
16th to endNight
22%12%28%28%7%
631
March1st to 15thNight
19%7%29%31%11%1
720
16th to endNight
19%326%33%14%2
687
April1st to 15thNight
21%7%28%31%9%1
539
16th to endNight
21%322%34%16%2
540
May1st to 15thNight
19%317%42%15%2
540
16th to endNight
11%317%37%25%4
563
June1st to 15thNight
14%114%39%26%4
540
16th to endNight
9%113%42%27%4
540
July1st to 15thNight
7%9%37%38%5%
510
16th to endNight
8%19%41%32%6%
564
August1st to 15thNight
8%110%41%32%6%
539
16th to endNight
14%111%32%32%6%
573
September1st to 15thNight
17%211%35%22%8%
568
16th to endNight
15%416%27%29%7%
657
October1st to 15thNight
23%318%29%21%2
660
16th to endNight
30%10%25%24%7%1
704
November1st to 15thNight
25%9%24%27%11%
700
16th to endNight
30%13%25%22%7%
750
December1st to 15thNight
34%14%28%19%2
900
16th to endNight
30%13%32%19%3
960
Page generated at 2017-09-13 07:39:26. Version ac04

Copyright 2017 A. Danko


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