Fingal Wildlife Centre
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fingal Wildlife Centre clear sky chart from 2005-11-05 to 2017-08-12.

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%
14852
16%
46236
11%
14815
45%
14815
21%
31475

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%
717
11%
2351
4%
716
23%
716
9%
1844
January16th to endNight
18%
768
11%
2496
5%
768
26%
768
11%
1948
February1st to 15thNight
19%
701
10%
2287
3%
701
28%
701
11%
1739
February16th to endNight
26%
631
14%
1945
6%
631
34%
631
15%
1449
March1st to 15thNight
29%
720
16%
2015
9%
720
35%
720
19%
1468
March16th to endNight
35%
768
20%
2112
11%
768
41%
768
24%
1459
April1st to 15thNight
33%
679
17%
1837
8%
679
39%
679
23%
1307
April16th to endNight
43%
540
21%
1620
11%
540
50%
540
27%
1030
May1st to 15thNight
46%
540
16%
1620
11%
540
51%
540
24%
1088
May16th to endNight
55%
447
17%
1570
17%
447
60%
447
29%
903
June1st to 15thNight
55%
360
15%
1410
18%
360
61%
360
27%
777
June16th to endNight
60%
360
19%
1260
18%
360
67%
360
29%
722
July1st to 15thNight
70%
408
19%
1299
22%
408
72%
408
37%
713
July16th to endNight
67%
564
17%
1595
15%
531
69%
531
37%
905
August1st to 15thNight
72%
527
19%
1575
14%
524
74%
524
38%
894
August16th to endNight
66%
533
24%
1583
17%
533
70%
533
38%
911
September1st to 15thNight
61%
660
25%
1740
16%
660
65%
660
35%
1086
September16th to endNight
59%
657
22%
1815
16%
657
62%
657
34%
1114
October1st to 15thNight
48%
660
21%
1953
19%
660
52%
660
28%
1236
October16th to endNight
26%
704
15%
2128
8%
704
35%
704
18%
1514
November1st to 15thNight
38%
700
21%
2297
17%
700
46%
700
23%
1455
November16th to endNight
25%
720
12%
2520
7%
720
31%
720
12%
1832
December1st to 15thNight
16%
720
8%
2520
3%
720
23%
720
10%
1916
December16th to endNight
15%
768
8%
2688
2%
768
22%
768
8%
2165

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%8%46%6%35%5%5%7%32%
47725
Night
15%8%46%5%3445%6%34%
46418
Cloud CoverDay
14%8%36%6%35%5%5%7%33%
47735
Night
15%8%36%5%3445%6%34%
46422
TransparencyDay
48%413%21%11%1
47425
Night
49%311%22%11%1
46236
SeeingDay
16%423%28%19%7%
5480
Night
19%6%25%30%15%2
14860

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
18%13%6%11%8%5%5%43417%
1584
16th to endDay
17%15%7%10%7%35%5%45%16%
1728
February1st to 15thDay
16%14%5%10%8%46%336%19%
1575
16th to endDay
15%10%5%10%8%47%5%5%5%19%
1527
March1st to 15thDay
17%10%5%9%6%445%46%24%
1933
16th to endDay
17%9%5%7%6%3445%7%29%
2112
April1st to 15thDay
18%9%5%6%5%35%45%7%28%
2120
16th to endDay
16%9%35%42435%7%37%
2340
May1st to 15thDay
15%7%36%6%35%45%7%33%
2331
16th to endDay
10%5%36%435%5%6%8%40%
2545
June1st to 15thDay
10%5%35%5%26%46%7%40%
2547
16th to endDay
9%5%244446%7%10%39%
2700
July1st to 15thDay
8%4145%345%6%10%44%
2576
16th to endDay
7%425%5%25%5%8%10%40%
2465
August1st to 15thDay
6%5%25%6%37%6%7%10%39%
2288
16th to endDay
10%425%5%35%5%7%8%42%
2256
September1st to 15thDay
11%6%35%5%35%46%7%40%
1889
16th to endDay
16%5%234245%7%9%38%
1815
October1st to 15thDay
14%7%36%6%45%5%47%36%
1676
16th to endDay
25%9%36%5%3345%6%26%
1741
November1st to 15thDay
14%6%36%436%5%5%6%37%
1561
16th to endDay
20%10%5%7%6%35%5%6%7%21%
1440
December1st to 15thDay
20%14%6%8%5%3445%6%20%
1440
16th to endDay
21%15%7%11%8%34345%13%
1536
January1st to 15thNight
21%14%6%8%5%35%44421%
2351
16th to endNight
16%16%8%8%8%25%45%5%19%
2496
February1st to 15thNight
16%14%6%8%6%4445%5%24%
2285
16th to endNight
17%9%5%8%8%35%5%46%25%
1945
March1st to 15thNight
19%8%46%6%34448%28%
2003
16th to endNight
16%8%36%5%34346%36%
2112
April1st to 15thNight
19%7%45%42445%6%34%
1837
16th to endNight
11%6%35%6%35%45%6%41%
1620
May1st to 15thNight
15%7%26%6%25%46%8%34%
1620
16th to endNight
10%4344246%5%7%46%
1568
June1st to 15thNight
11%415%4245%7%8%44%
1410
16th to endNight
9%4145%35%5%5%8%46%
1260
July1st to 15thNight
6%3245%24348%55%
1378
16th to endNight
7%4234235%5%10%49%
1703
August1st to 15thNight
5%313435%6%7%10%47%
1586
16th to endNight
8%423414447%53%
1583
September1st to 15thNight
10%4246%3445%6%48%
1740
16th to endNight
12%3144245%5%6%47%
1815
October1st to 15thNight
15%5%2443335%6%43%
1953
16th to endNight
20%8%36%5%345%6%6%29%
2128
November1st to 15thNight
13%6%35%5%35%45%7%38%
2297
16th to endNight
21%10%5%6%435%45%6%25%
2520
December1st to 15thNight
21%12%6%6%6%3445%6%21%
2520
16th to endNight
22%13%6%9%6%35%445%17%
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
18%13%5%9%9%46%435%17%
1584
16th to endDay
17%14%6%10%9%45%5%5%5%16%
1728
February1st to 15thDay
16%14%5%9%8%5%5%335%20%
1575
16th to endDay
15%10%5%11%7%47%5%6%5%20%
1527
March1st to 15thDay
18%10%6%7%6%45%446%25%
1944
16th to endDay
17%8%47%5%35%447%30%
2111
April1st to 15thDay
18%9%46%6%35%45%7%29%
2120
16th to endDay
16%8%35%42435%6%38%
2340
May1st to 15thDay
16%6%36%6%35%5%5%8%34%
2331
16th to endDay
10%5%25%435%46%8%41%
2545
June1st to 15thDay
10%5%25%5%35%6%6%7%41%
2547
16th to endDay
9%425%445%5%8%9%40%
2700
July1st to 15thDay
8%423425%5%6%10%45%
2576
16th to endDay
7%4245%346%8%11%41%
2465
August1st to 15thDay
7%425%5%46%6%8%9%40%
2288
16th to endDay
10%424435%46%8%44%
2256
September1st to 15thDay
12%5%25%5%35%5%5%6%41%
1889
16th to endDay
16%41342447%8%39%
1815
October1st to 15thDay
14%6%26%6%446%47%36%
1676
16th to endDay
25%9%35%5%3445%5%26%
1741
November1st to 15thDay
14%7%25%436%45%7%37%
1561
16th to endDay
20%10%47%6%45%5%5%7%21%
1440
December1st to 15thDay
20%14%5%8%6%35%35%7%19%
1440
16th to endDay
21%15%7%11%9%24345%13%
1536
January1st to 15thNight
22%14%6%7%6%34445%20%
2351
16th to endNight
16%15%7%8%7%25%45%5%19%
2496
February1st to 15thNight
15%15%5%8%6%4445%5%24%
2278
16th to endNight
18%9%5%7%8%35%445%26%
1945
March1st to 15thNight
20%7%45%6%3445%7%28%
2015
16th to endNight
16%8%36%42445%6%36%
2112
April1st to 15thNight
19%8%35%425%35%6%34%
1837
16th to endNight
11%6%25%5%35%45%6%41%
1620
May1st to 15thNight
15%6%35%5%35%46%8%34%
1619
16th to endNight
10%4343345%5%7%46%
1568
June1st to 15thNight
11%425%4245%6%8%44%
1410
16th to endNight
9%315%44446%8%46%
1260
July1st to 15thNight
6%3245%34438%55%
1378
16th to endNight
8%42342446%10%49%
1703
August1st to 15thNight
5%314435%5%8%9%47%
1586
16th to endNight
9%324324347%53%
1583
September1st to 15thNight
10%4145%3445%6%48%
1740
16th to endNight
12%3244245%6%6%47%
1815
October1st to 15thNight
15%5%25%423446%44%
1953
16th to endNight
20%8%36%5%345%6%5%30%
2128
November1st to 15thNight
13%6%35%435%5%5%7%39%
2297
16th to endNight
22%9%47%5%25%45%5%25%
2520
December1st to 15thNight
22%12%5%7%5%3435%6%22%
2520
16th to endNight
22%13%6%9%6%36%445%17%
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
70%39%11%4
1585
16th to endDay
69%210%12%4
1728
February1st to 15thDay
66%39%14%5%
1577
16th to endDay
62%411%16%4
1527
March1st to 15thDay
60%312%15%7%
1944
16th to endDay
52%410%21%10%
2112
April1st to 15thDay
53%311%19%11%
2120
16th to endDay
45%312%20%15%2
2340
May1st to 15thDay
47%311%24%11%1
2331
16th to endDay
38%414%25%14%1
2549
June1st to 15thDay
38%5%13%26%13%1
2547
16th to endDay
35%6%15%24%16%
2700
July1st to 15thDay
32%5%10%30%18%2
2426
16th to endDay
33%5%18%25%14%2
2310
August1st to 15thDay
35%5%17%25%13%1
2275
16th to endDay
35%415%28%13%2
2256
September1st to 15thDay
40%415%27%11%
1889
16th to endDay
39%415%28%12%
1815
October1st to 15thDay
46%413%21%13%1
1676
16th to endDay
57%314%16%6%
1741
November1st to 15thDay
45%415%22%10%1
1561
16th to endDay
62%314%14%4
1440
December1st to 15thDay
65%414%11%3
1440
16th to endDay
74%310%9%2
1536
January1st to 15thNight
66%29%12%7%
2351
16th to endNight
65%211%15%4
2496
February1st to 15thNight
61%410%16%6%
2287
16th to endNight
59%210%20%6%
1945
March1st to 15thNight
53%410%22%7%1
2015
16th to endNight
47%39%24%12%2
2112
April1st to 15thNight
50%38%22%12%1
1837
16th to endNight
41%38%22%19%3
1620
May1st to 15thNight
47%310%23%12%3
1620
16th to endNight
36%313%26%16%3
1570
June1st to 15thNight
36%312%29%16%1
1410
16th to endNight
34%5%11%26%19%2
1260
July1st to 15thNight
30%47%31%22%4
1299
16th to endNight
30%413%27%19%3
1595
August1st to 15thNight
29%5%15%32%15%2
1575
16th to endNight
31%411%32%17%3
1583
September1st to 15thNight
35%312%29%16%2
1740
16th to endNight
35%413%30%15%
1815
October1st to 15thNight
41%312%23%19%
1953
16th to endNight
53%312%21%8%
2128
November1st to 15thNight
44%313%24%12%2
2297
16th to endNight
59%213%18%5%
2520
December1st to 15thNight
63%214%13%5%
2520
16th to endNight
69%311%12%3
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
20%14%40%15%8%2
85
16th to endDay
30%7%39%19%3
96
February1st to 15thDay
24%6%46%22%
90
16th to endDay
17%13%43%20%4
81
March1st to 15thDay
23%10%27%27%10%
234
16th to endDay
21%432%28%10%2
288
April1st to 15thDay
24%431%27%11%1
270
16th to endDay
21%229%22%14%8%
270
May1st to 15thDay
21%321%30%15%6%
288
16th to endDay
13%320%32%19%10%
331
June1st to 15thDay
12%320%35%22%5%
342
16th to endDay
10%124%35%22%5%
495
July1st to 15thDay
10%216%32%27%10%
431
16th to endDay
8%14%30%31%14%
326
August1st to 15thDay
7%112%35%24%19%
297
16th to endDay
12%110%28%28%19%
268
September1st to 15thDay
12%210%25%32%16%
255
16th to endDay
20%213%23%26%12%
254
October1st to 15thDay
16%5%21%27%21%6%
255
16th to endDay
26%7%33%23%9%
253
November1st to 15thDay
13%6%29%28%14%5%
87
16th to endDay
23%15%36%16%5%3
60
December1st to 15thDay
25%23%33%11%5%1
60
16th to endDay
32%21%28%17%
64
January1st to 15thNight
29%12%34%18%5%
720
16th to endNight
25%11%30%26%5%
768
February1st to 15thNight
23%9%34%26%5%
704
16th to endNight
22%7%30%31%6%
631
March1st to 15thNight
23%6%31%29%8%
720
16th to endNight
21%331%29%13%1
768
April1st to 15thNight
23%5%29%31%8%
679
16th to endNight
14%330%35%14%2
540
May1st to 15thNight
16%222%37%17%1
540
16th to endNight
13%220%38%20%4
449
June1st to 15thNight
15%120%37%23%1
360
16th to endNight
10%18%44%23%2
360
July1st to 15thNight
8%11%41%33%4
408
16th to endNight
9%111%43%28%5%
564
August1st to 15thNight
7%10%40%33%6%
527
16th to endNight
11%12%33%35%6%
533
September1st to 15thNight
12%313%31%29%8%
660
16th to endNight
13%217%31%27%7%
657
October1st to 15thNight
18%5%20%32%21%2
660
16th to endNight
23%9%32%26%6%
704
November1st to 15thNight
17%7%28%30%14%2
700
16th to endNight
28%12%25%21%10%1
720
December1st to 15thNight
30%13%31%19%5%
720
16th to endNight
28%11%33%21%4
768
Page generated at 2017-08-13 14:16:19. Version ac04

Copyright 2017 A. Danko


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