Port Crescent State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Port Crescent State Park clear sky chart from 2005-11-05 to 2017-12-20.

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
34%
15861
14%
48016
9%
15821
39%
15821
19%
33901

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%
898
9%
2506
2%
895
20%
895
11%
2021
January16th to endNight
18%
885
10%
2613
4%
885
25%
885
12%
2052
February1st to 15thNight
17%
701
9%
2287
3%
701
23%
701
10%
1748
February16th to endNight
24%
631
13%
1901
5%
631
32%
631
14%
1424
March1st to 15thNight
25%
720
15%
2070
8%
720
31%
720
17%
1515
March16th to endNight
33%
768
18%
2112
10%
768
40%
768
22%
1483
April1st to 15thNight
28%
595
16%
1792
8%
595
35%
595
22%
1212
April16th to endNight
39%
540
19%
1620
11%
540
45%
540
24%
1065
May1st to 15thNight
45%
540
16%
1620
13%
540
49%
540
25%
1067
May16th to endNight
48%
493
17%
1570
13%
492
55%
492
28%
941
June1st to 15thNight
44%
360
15%
1260
14%
360
50%
360
25%
757
June16th to endNight
55%
360
16%
1260
15%
360
61%
360
29%
724
July1st to 15thNight
65%
446
17%
1296
16%
446
66%
446
40%
730
July16th to endNight
60%
564
15%
1475
12%
531
62%
531
36%
900
August1st to 15thNight
64%
539
19%
1609
17%
536
66%
536
35%
942
August16th to endNight
57%
573
22%
1719
15%
573
61%
573
34%
1015
September1st to 15thNight
54%
671
19%
1912
14%
671
57%
671
31%
1188
September16th to endNight
56%
717
24%
1980
17%
717
60%
717
33%
1229
October1st to 15thNight
39%
720
16%
2090
12%
720
44%
720
22%
1454
October16th to endNight
25%
768
13%
2409
8%
768
33%
768
13%
1805
November1st to 15thNight
29%
760
14%
2471
12%
760
33%
760
14%
1796
November16th to endNight
20%
780
9%
2704
5%
780
24%
780
9%
2121
December1st to 15thNight
12%
848
6%
2798
2%
848
17%
848
8%
2268
December16th to endNight
13%
984
8%
2942
2%
984
19%
984
8%
2444

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
13%8%36%5%345%5%7%35%
48815
Night
15%10%47%6%34446%32%
48191
Cloud CoverDay
13%8%36%5%3445%7%34%
48825
Night
15%10%47%6%34446%31%
48195
TransparencyDay
48%413%22%10%1
48508
Night
52%311%21%10%1
48016
SeeingDay
17%7%26%26%15%6%
6152
Night
20%8%27%28%13%2
15867

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%14%6%10%8%46%5%35%17%
1432
16th to endDay
13%14%8%11%9%5%6%6%6%413%
1608
February1st to 15thDay
13%14%6%10%7%45%5%45%22%
1575
16th to endDay
13%10%5%8%8%46%5%5%7%25%
1572
March1st to 15thDay
13%9%310%7%35%5%46%28%
1879
16th to endDay
14%9%5%8%6%35%446%31%
2112
April1st to 15thDay
17%9%45%5%23447%33%
2166
16th to endDay
14%6%25%435%45%7%39%
2340
May1st to 15thDay
16%5%25%5%3436%7%38%
2331
16th to endDay
11%425%5%2445%7%45%
2542
June1st to 15thDay
10%5%245%3446%7%43%
2700
16th to endDay
10%5%245%345%6%8%42%
2700
July1st to 15thDay
7%3144145%6%10%49%
2581
16th to endDay
8%3144346%7%9%46%
2589
August1st to 15thDay
8%415%435%5%5%9%44%
2340
16th to endDay
10%5%25%43445%8%46%
2483
September1st to 15thDay
14%5%243245%5%8%43%
2034
16th to endDay
14%5%25%42445%8%41%
1980
October1st to 15thDay
19%8%36%6%23445%36%
1869
16th to endDay
24%9%36%5%35%45%7%23%
1813
November1st to 15thDay
17%13%46%6%35%45%7%26%
1717
16th to endDay
17%15%6%11%8%45%445%17%
1586
December1st to 15thDay
13%17%8%11%8%4445%415%
1488
16th to endDay
19%16%7%11%7%45%5%45%14%
1378
January1st to 15thNight
20%12%6%9%8%4445%5%18%
2506
16th to endNight
13%12%7%9%9%45%45%6%20%
2613
February1st to 15thNight
14%15%6%9%6%35%446%23%
2285
16th to endNight
15%12%49%7%245%5%6%25%
1901
March1st to 15thNight
13%11%5%8%6%24445%32%
2058
16th to endNight
14%9%5%6%5%34435%36%
2112
April1st to 15thNight
19%10%44422448%33%
1792
16th to endNight
17%7%25%5%33446%39%
1620
May1st to 15thNight
13%6%36%445%5%5%7%38%
1620
16th to endNight
12%5%23425%5%5%6%45%
1568
June1st to 15thNight
12%5%25%42446%8%41%
1260
16th to endNight
9%5%245%26%6%5%8%43%
1260
July1st to 15thNight
6%41443445%7%52%
1375
16th to endNight
7%4245%345%6%9%46%
1576
August1st to 15thNight
8%315%4345%7%9%46%
1620
16th to endNight
9%5%15%42435%7%49%
1719
September1st to 15thNight
13%5%25%423346%46%
1912
16th to endNight
12%5%35%32445%6%44%
1980
October1st to 15thNight
17%7%27%6%34436%36%
2090
16th to endNight
24%11%36%5%34445%26%
2409
November1st to 15thNight
15%12%5%8%6%34446%28%
2471
16th to endNight
21%14%6%9%6%3444419%
2704
December1st to 15thNight
19%16%8%10%7%34435%16%
2798
16th to endNight
19%16%9%9%6%35%5%45%15%
2942

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%14%7%10%8%46%5%45%16%
1432
16th to endDay
13%14%8%13%10%5%5%45%5%13%
1608
February1st to 15thDay
13%14%5%10%8%45%445%21%
1575
16th to endDay
12%11%48%7%45%6%5%8%24%
1572
March1st to 15thDay
14%9%49%7%36%5%45%28%
1890
16th to endDay
14%8%5%9%5%4445%6%31%
2111
April1st to 15thDay
17%9%35%5%33447%34%
2166
16th to endDay
14%7%24425%45%8%39%
2340
May1st to 15thDay
15%6%25%5%2445%7%39%
2331
16th to endDay
11%5%25%5%2345%7%46%
2542
June1st to 15thDay
10%5%245%25%5%6%8%43%
2700
16th to endDay
10%4344246%6%9%41%
2700
July1st to 15thDay
7%31442347%10%50%
2581
16th to endDay
8%324435%5%7%9%47%
2589
August1st to 15thDay
9%415%425%5%6%9%45%
2340
16th to endDay
11%5%25%4245%5%8%46%
2483
September1st to 15thDay
14%425%3245%5%8%43%
2034
16th to endDay
14%6%2442445%8%41%
1980
October1st to 15thDay
19%7%36%5%24436%35%
1869
16th to endDay
24%10%37%5%345%46%22%
1813
November1st to 15thDay
18%12%48%5%45%446%26%
1717
16th to endDay
16%18%6%10%7%3445%5%16%
1586
December1st to 15thDay
15%18%8%11%10%45%44413%
1488
16th to endDay
20%15%7%11%9%35%435%12%
1378
January1st to 15thNight
20%12%6%9%9%45%445%16%
2506
16th to endNight
13%11%7%10%10%5%6%445%19%
2613
February1st to 15thNight
14%15%6%8%7%46%446%21%
2278
16th to endNight
15%11%49%6%345%5%6%25%
1901
March1st to 15thNight
14%11%5%8%5%34445%32%
2070
16th to endNight
15%9%46%5%34446%36%
2112
April1st to 15thNight
20%9%35%41345%7%34%
1792
16th to endNight
17%6%35%43335%6%39%
1620
May1st to 15thNight
13%6%26%5%35%448%38%
1619
16th to endNight
13%325%335%5%6%7%44%
1568
June1st to 15thNight
13%426%5%245%6%8%41%
1260
16th to endNight
9%425%5%35%45%9%43%
1260
July1st to 15thNight
6%414425%46%8%51%
1375
16th to endNight
7%326%5%345%5%9%46%
1576
August1st to 15thNight
9%3144345%6%8%46%
1620
16th to endNight
10%5%25%42345%7%48%
1719
September1st to 15thNight
14%5%25%424346%46%
1912
16th to endNight
12%6%25%4245%5%6%44%
1980
October1st to 15thNight
17%7%36%6%44446%34%
2090
16th to endNight
24%11%47%5%34435%25%
2409
November1st to 15thNight
15%13%5%8%6%34445%26%
2471
16th to endNight
22%15%410%7%3434418%
2704
December1st to 15thNight
19%16%8%11%7%35%335%14%
2798
16th to endNight
19%16%9%9%6%45%445%13%
2942

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
68%39%13%3
1433
16th to endDay
71%49%10%3
1608
February1st to 15thDay
64%411%15%5%
1577
16th to endDay
57%312%17%6%1
1572
March1st to 15thDay
58%412%16%8%
1890
16th to endDay
54%313%19%8%
2112
April1st to 15thDay
52%311%20%11%
2166
16th to endDay
44%316%19%14%2
2340
May1st to 15thDay
44%310%26%12%2
2331
16th to endDay
38%413%26%15%2
2546
June1st to 15thDay
37%414%27%15%
2700
16th to endDay
37%415%26%14%
2700
July1st to 15thDay
29%314%31%17%2
2431
16th to endDay
34%416%26%16%2
2427
August1st to 15thDay
35%416%29%12%1
2327
16th to endDay
37%414%29%13%1
2483
September1st to 15thDay
39%5%13%31%10%
2034
16th to endDay
41%415%28%9%
1980
October1st to 15thDay
50%39%23%10%1
1869
16th to endDay
60%415%15%3
1813
November1st to 15thDay
58%413%16%7%
1717
16th to endDay
68%412%10%3
1586
December1st to 15thDay
71%411%10%2
1488
16th to endDay
72%410%10%1
1378
January1st to 15thNight
66%29%14%5%
2506
16th to endNight
63%413%15%3
2613
February1st to 15thNight
61%410%16%5%
2287
16th to endNight
59%312%16%7%
1901
March1st to 15thNight
54%311%22%7%1
2070
16th to endNight
50%211%22%11%1
2112
April1st to 15thNight
49%210%22%13%1
1792
16th to endNight
45%38%20%18%3
1620
May1st to 15thNight
44%49%24%14%2
1620
16th to endNight
38%311%28%14%4
1570
June1st to 15thNight
40%311%25%17%1
1260
16th to endNight
36%415%24%19%1
1260
July1st to 15thNight
29%412%30%20%2
1296
16th to endNight
34%417%24%16%2
1475
August1st to 15thNight
33%415%31%13%1
1609
16th to endNight
34%312%30%16%1
1719
September1st to 15thNight
38%311%30%14%
1912
16th to endNight
37%212%33%11%
1980
October1st to 15thNight
48%49%24%11%
2090
16th to endNight
59%311%19%5%
2409
November1st to 15thNight
57%412%18%7%
2471
16th to endNight
66%313%13%3
2704
December1st to 15thNight
69%311%11%4
2798
16th to endNight
70%310%11%3
2942

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
21%10%44%15%8%
90
16th to endDay
27%5%37%25%5%
96
February1st to 15thDay
25%17%37%17%1
90
16th to endDay
13%23%30%23%8%
81
March1st to 15thDay
22%16%31%24%5%
180
16th to endDay
22%6%30%25%10%4
288
April1st to 15thDay
24%8%30%24%11%2
270
16th to endDay
22%8%31%20%12%5%
270
May1st to 15thDay
18%7%29%22%14%5%
288
16th to endDay
13%5%30%26%16%6%
373
June1st to 15thDay
13%6%28%32%14%4
495
16th to endDay
12%5%29%29%16%6%
495
July1st to 15thDay
9%324%32%21%8%
475
16th to endDay
11%223%33%19%9%
449
August1st to 15thDay
10%214%31%25%15%
313
16th to endDay
14%416%25%23%15%
332
September1st to 15thDay
13%119%28%20%17%
315
16th to endDay
15%416%24%26%13%
314
October1st to 15thDay
25%6%24%25%13%5%
315
16th to endDay
29%10%33%20%5%
229
November1st to 15thDay
23%8%31%23%8%2
135
16th to endDay
18%20%32%21%5%1
96
December1st to 15thDay
22%22%35%16%3
90
16th to endDay
28%24%34%12%
73
January1st to 15thNight
26%12%34%19%5%1
900
16th to endNight
16%12%37%24%8%
885
February1st to 15thNight
23%13%34%22%5%
704
16th to endNight
21%10%31%27%8%
631
March1st to 15thNight
20%10%34%25%9%
720
16th to endNight
19%8%28%30%11%1
768
April1st to 15thNight
23%9%32%24%9%
595
16th to endNight
21%7%25%30%12%2
540
May1st to 15thNight
16%5%22%38%14%2
540
16th to endNight
14%5%25%33%19%1
494
June1st to 15thNight
14%325%36%18%1
360
16th to endNight
11%122%39%22%2
360
July1st to 15thNight
10%15%44%25%3
446
16th to endNight
8%118%40%26%4
564
August1st to 15thNight
11%111%38%33%3
539
16th to endNight
13%316%31%29%6%
573
September1st to 15thNight
16%318%29%21%9%
671
16th to endNight
14%5%15%33%22%8%
717
October1st to 15thNight
21%6%24%29%15%1
720
16th to endNight
30%9%26%28%4
768
November1st to 15thNight
21%11%29%23%12%
760
16th to endNight
28%14%27%21%6%
780
December1st to 15thNight
26%16%34%18%4
848
16th to endNight
27%12%35%20%4
984
Page generated at 2017-12-21 07:04:52. Version ac04

Copyright 2017 A. Danko


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