Prinyer's Cove
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Prinyer's Cove 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
32%
14736
14%
46816
9%
14706
38%
14706
17%
32571

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
14%
720
8%
2506
4%
716
21%
716
7%
1983
January16th to endNight
20%
768
10%
2572
5%
768
27%
768
10%
1953
February1st to 15thNight
17%
703
9%
2287
4%
701
23%
701
10%
1774
February16th to endNight
24%
631
13%
1967
6%
631
33%
631
14%
1433
March1st to 15thNight
24%
720
14%
2054
7%
720
31%
720
14%
1517
March16th to endNight
31%
768
19%
2064
8%
768
40%
768
22%
1399
April1st to 15thNight
28%
718
17%
1796
5%
718
33%
718
22%
1301
April16th to endNight
33%
661
18%
1741
5%
661
42%
661
23%
1169
May1st to 15thNight
37%
384
17%
1464
14%
384
46%
384
15%
928
May16th to endNight
42%
374
16%
1497
13%
374
54%
374
18%
882
June1st to 15thNight
40%
360
12%
1440
13%
360
48%
360
17%
907
June16th to endNight
48%
360
11%
1440
13%
360
55%
360
18%
867
July1st to 15thNight
55%
340
16%
1360
23%
340
60%
340
27%
718
July16th to endNight
53%
376
17%
1418
19%
354
63%
354
27%
744
August1st to 15thNight
56%
521
15%
1592
12%
519
59%
519
27%
968
August16th to endNight
59%
696
23%
1842
12%
696
64%
696
37%
1102
September1st to 15thNight
54%
707
19%
1768
10%
707
56%
707
33%
1147
September16th to endNight
49%
657
22%
1807
14%
657
54%
657
31%
1141
October1st to 15thNight
34%
660
16%
1980
13%
660
39%
660
18%
1392
October16th to endNight
21%
704
9%
2153
4%
704
28%
704
12%
1652
November1st to 15thNight
32%
700
18%
2340
15%
700
39%
700
18%
1572
November16th to endNight
19%
720
12%
2520
7%
720
27%
720
10%
1906
December1st to 15thNight
14%
720
6%
2520
3%
720
19%
720
8%
1982
December16th to endNight
11%
768
8%
2688
2%
768
18%
768
8%
2134

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
15%7%36%5%345%5%7%35%
47852
Night
17%8%36%5%3445%6%34%
46986
Cloud CoverDay
15%7%35%5%3445%7%37%
47862
Night
18%8%36%5%3445%6%34%
46991
TransparencyDay
46%6%13%21%10%1
47540
Night
49%5%12%19%11%1
46816
SeeingDay
18%11%20%27%17%4
5448
Night
19%19%22%24%12%1
14738

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
20%12%46%6%2435%5%27%
1432
16th to endDay
13%14%6%7%7%5%7%5%5%5%21%
1650
February1st to 15thDay
14%11%6%12%8%35%5%5%5%21%
1575
16th to endDay
19%11%46%5%345%45%28%
1506
March1st to 15thDay
16%8%48%8%44445%28%
1894
16th to endDay
16%6%36%5%33345%40%
2160
April1st to 15thDay
20%7%36%5%34446%34%
2152
16th to endDay
17%5%26%6%34447%38%
2229
May1st to 15thDay
14%6%27%5%345%5%7%36%
2485
16th to endDay
12%435%4245%6%8%41%
2618
June1st to 15thDay
18%5%25%5%345%5%8%35%
2520
16th to endDay
12%5%25%5%245%6%8%40%
2520
July1st to 15thDay
9%324435%5%6%8%46%
2520
16th to endDay
9%325%5%35%5%7%9%41%
2654
August1st to 15thDay
8%426%435%6%5%9%42%
2355
16th to endDay
11%3134245%6%8%46%
2348
September1st to 15thDay
13%5%2442445%6%46%
2112
16th to endDay
13%5%25%424447%44%
1821
October1st to 15thDay
18%6%245%235%5%7%36%
1650
16th to endDay
25%8%26%5%34447%27%
1718
November1st to 15thDay
14%6%45%5%35%5%6%6%35%
1517
16th to endDay
21%10%28%5%35%5%47%25%
1440
December1st to 15thDay
20%14%5%7%6%35%5%5%6%19%
1440
16th to endDay
23%14%5%7%6%33445%21%
1536
January1st to 15thNight
22%12%47%6%34445%22%
2506
16th to endNight
16%13%47%7%35%446%24%
2572
February1st to 15thNight
15%13%5%10%6%35%445%25%
2285
16th to endNight
17%9%46%5%4445%6%29%
1967
March1st to 15thNight
20%8%47%5%3434433%
2042
16th to endNight
16%8%35%422445%42%
2064
April1st to 15thNight
22%7%35%315%346%34%
1796
16th to endNight
15%5%244345%5%6%41%
1741
May1st to 15thNight
19%5%34434446%39%
1464
16th to endNight
12%5%245%35%5%5%6%43%
1495
June1st to 15thNight
15%5%26%4345%7%9%36%
1440
16th to endNight
12%5%25%435%46%8%39%
1440
July1st to 15thNight
7%3145%35%45%8%49%
1440
16th to endNight
8%32442348%9%47%
1514
August1st to 15thNight
9%4245%3446%8%45%
1602
16th to endNight
6%3244245%6%8%51%
1842
September1st to 15thNight
14%42442335%7%47%
1768
16th to endNight
15%324423446%48%
1807
October1st to 15thNight
19%7%35%6%34346%35%
1980
16th to endNight
23%7%36%6%35%446%27%
2153
November1st to 15thNight
18%6%35%43445%7%36%
2340
16th to endNight
24%8%35%5%25%5%5%6%26%
2520
December1st to 15thNight
22%13%46%42445%6%24%
2520
16th to endNight
22%13%5%7%6%3445%6%20%
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
21%13%47%6%35%45%6%22%
1432
16th to endDay
14%14%49%7%5%7%5%5%5%21%
1650
February1st to 15thDay
15%12%6%11%9%25%45%5%21%
1575
16th to endDay
20%11%46%5%35%445%29%
1506
March1st to 15thDay
17%9%47%7%345%6%5%28%
1905
16th to endDay
16%7%35%433436%41%
2159
April1st to 15thDay
20%8%24434446%36%
2152
16th to endDay
17%425%5%345%5%7%39%
2229
May1st to 15thDay
14%5%35%5%345%5%7%38%
2485
16th to endDay
12%4244346%6%8%43%
2618
June1st to 15thDay
18%5%3443445%8%37%
2520
16th to endDay
12%5%245%2345%9%44%
2520
July1st to 15thDay
8%3244345%5%8%49%
2520
16th to endDay
9%415%5%25%5%5%9%44%
2654
August1st to 15thDay
8%4245%25%47%8%45%
2355
16th to endDay
11%32333446%8%49%
2348
September1st to 15thDay
14%42442345%7%46%
2112
16th to endDay
12%6%25%42445%6%44%
1821
October1st to 15thDay
19%5%25%435%45%6%37%
1650
16th to endDay
26%8%346%2445%5%27%
1718
November1st to 15thDay
15%7%36%5%36%45%7%34%
1517
16th to endDay
23%10%37%6%345%46%24%
1440
December1st to 15thDay
23%13%5%8%6%345%5%5%19%
1440
16th to endDay
24%16%5%6%5%3445%5%18%
1536
January1st to 15thNight
23%12%47%6%35%445%20%
2506
16th to endNight
17%13%38%6%35%5%5%7%23%
2572
February1st to 15thNight
16%14%6%11%5%44435%24%
2278
16th to endNight
18%9%47%5%2445%6%28%
1967
March1st to 15thNight
21%9%36%5%3434433%
2054
16th to endNight
17%7%35%422436%40%
2064
April1st to 15thNight
23%7%35%313447%35%
1796
16th to endNight
16%425%423447%42%
1741
May1st to 15thNight
19%5%25%42445%6%39%
1464
16th to endNight
13%424435%5%5%7%43%
1495
June1st to 15thNight
15%6%25%5%335%6%8%36%
1440
16th to endNight
11%5%26%445%45%9%40%
1440
July1st to 15thNight
6%3245%35%5%5%9%49%
1440
16th to endNight
9%325%42447%10%47%
1514
August1st to 15thNight
10%415%5%25%5%6%8%45%
1602
16th to endNight
7%3144245%5%8%51%
1842
September1st to 15thNight
14%5%14424347%47%
1768
16th to endNight
15%5%24312447%47%
1807
October1st to 15thNight
20%7%36%424345%36%
1980
16th to endNight
25%8%36%5%35%445%26%
2153
November1st to 15thNight
19%5%35%42445%7%36%
2340
16th to endNight
25%10%37%5%345%45%25%
2520
December1st to 15thNight
24%12%5%6%424446%23%
2520
16th to endNight
23%13%5%7%5%2445%6%19%
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
60%6%11%14%5%
1433
16th to endDay
64%5%10%10%7%
1650
February1st to 15thDay
64%5%11%13%3
1577
16th to endDay
57%412%14%10%
1506
March1st to 15thDay
56%414%17%6%1
1905
16th to endDay
44%410%22%15%3
2160
April1st to 15thDay
49%39%21%12%2
2152
16th to endDay
44%5%8%21%16%3
2229
May1st to 15thDay
43%6%11%21%13%2
2485
16th to endDay
37%6%17%24%12%2
2622
June1st to 15thDay
45%6%14%21%10%1
2520
16th to endDay
37%5%16%24%14%1
2520
July1st to 15thDay
31%6%13%32%15%
2371
16th to endDay
35%7%18%27%10%
2487
August1st to 15thDay
34%7%18%25%12%1
2341
16th to endDay
31%6%16%32%13%
2348
September1st to 15thDay
38%415%27%12%
2112
16th to endDay
38%5%13%30%11%
1821
October1st to 15thDay
45%6%14%21%11%
1650
16th to endDay
57%5%13%18%5%
1718
November1st to 15thDay
47%8%13%18%9%1
1517
16th to endDay
59%6%13%13%7%
1440
December1st to 15thDay
66%6%14%9%2
1440
16th to endDay
66%6%10%11%4
1536
January1st to 15thNight
64%6%10%12%5%
2506
16th to endNight
60%5%11%14%7%
2572
February1st to 15thNight
63%412%15%4
2287
16th to endNight
55%413%17%8%
1967
March1st to 15thNight
55%410%19%8%
2054
16th to endNight
44%411%19%17%2
2064
April1st to 15thNight
49%48%20%15%2
1796
16th to endNight
41%5%11%19%19%3
1741
May1st to 15thNight
46%410%19%16%2
1464
16th to endNight
39%6%12%23%15%3
1497
June1st to 15thNight
44%6%12%22%14%
1440
16th to endNight
41%5%14%21%16%1
1440
July1st to 15thNight
30%5%10%28%23%1
1360
16th to endNight
30%6%13%31%16%2
1418
August1st to 15thNight
34%7%17%26%13%
1592
16th to endNight
29%6%13%34%14%1
1842
September1st to 15thNight
35%5%15%28%12%1
1768
16th to endNight
37%412%31%13%
1807
October1st to 15thNight
50%411%22%10%
1980
16th to endNight
59%5%14%13%6%
2153
November1st to 15thNight
46%6%14%19%11%1
2340
16th to endNight
58%7%13%14%5%
2520
December1st to 15thNight
62%7%14%12%2
2520
16th to endNight
64%6%12%10%4
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
15%28%26%20%6%3
60
16th to endDay
31%14%31%16%41
83
February1st to 15thDay
23%13%46%15%1
90
16th to endDay
30%15%24%23%6%
165
March1st to 15thDay
24%17%20%29%8%
270
16th to endDay
25%13%26%23%9%1
288
April1st to 15thDay
23%15%29%19%10%1
270
16th to endDay
17%15%24%23%14%4
270
May1st to 15thDay
21%13%18%28%13%4
288
16th to endDay
13%10%25%29%15%5%
331
June1st to 15thDay
16%11%17%34%17%2
315
16th to endDay
15%10%19%30%20%3
315
July1st to 15thDay
11%7%11%35%26%8%
305
16th to endDay
11%11%15%31%24%6%
326
August1st to 15thDay
12%6%11%29%32%7%
313
16th to endDay
11%7%11%28%26%13%
332
September1st to 15thDay
14%6%16%24%26%12%
299
16th to endDay
15%9%17%30%18%9%
254
October1st to 15thDay
19%10%27%19%19%4
255
16th to endDay
28%14%25%24%7%
264
November1st to 15thDay
12%15%25%30%13%1
171
16th to endDay
26%10%25%21%15%1
60
December1st to 15thDay
10%25%28%26%6%3
60
16th to endDay
43%18%25%12%
64
January1st to 15thNight
23%26%26%16%5%
720
16th to endNight
19%23%27%23%5%
768
February1st to 15thNight
20%22%31%21%4
704
16th to endNight
18%20%27%26%6%
631
March1st to 15thNight
24%21%22%26%5%
720
16th to endNight
19%19%23%27%9%1
768
April1st to 15thNight
21%20%25%24%7%
718
16th to endNight
16%20%23%24%13%1
661
May1st to 15thNight
21%19%16%26%13%2
384
16th to endNight
12%18%20%33%13%2
375
June1st to 15thNight
15%18%18%29%16%1
360
16th to endNight
12%18%15%34%17%1
360
July1st to 15thNight
7%13%16%33%25%3
340
16th to endNight
7%17%15%36%21%2
376
August1st to 15thNight
12%9%11%35%24%5%
521
16th to endNight
7%10%14%33%29%4
696
September1st to 15thNight
14%10%15%28%25%5%
707
16th to endNight
15%12%17%24%22%6%
657
October1st to 15thNight
23%15%21%21%16%1
660
16th to endNight
25%17%27%22%7%
704
November1st to 15thNight
19%19%24%22%12%1
700
16th to endNight
24%26%23%16%8%
720
December1st to 15thNight
28%26%25%14%5%
720
16th to endNight
26%23%28%16%3
768
Page generated at 2017-09-13 07:39:13. Version ac04

Copyright 2017 A. Danko


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