Angelus Oaks Heliport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Angelus Oaks Heliport clear sky chart from 2005-11-05 to 2018-03-11.

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
64%
16749
35%
48995
27%
16709
71%
16709
51%
24215

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
50%
776
29%
2522
22%
776
61%
776
37%
1338
January16th to endNight
51%
832
33%
2524
24%
832
62%
832
37%
1407
February1st to 15thNight
54%
759
33%
2288
28%
758
63%
758
41%
1232
February16th to endNight
45%
684
30%
2051
25%
684
55%
684
34%
1176
March1st to 15thNight
52%
764
28%
2292
22%
764
62%
764
37%
1259
March16th to endNight
54%
768
30%
2037
21%
768
62%
768
44%
1152
April1st to 15thNight
44%
719
32%
1799
13%
719
54%
719
45%
1010
April16th to endNight
53%
720
34%
1800
15%
720
62%
720
56%
928
May1st to 15thNight
61%
560
35%
1640
22%
560
68%
560
58%
733
May16th to endNight
58%
561
34%
1685
21%
561
67%
561
59%
744
June1st to 15thNight
73%
540
33%
1620
26%
540
77%
540
70%
660
June16th to endNight
81%
464
39%
1544
36%
464
86%
464
80%
540
July1st to 15thNight
89%
451
31%
1471
30%
451
89%
451
62%
607
July16th to endNight
85%
594
32%
1621
26%
559
86%
559
56%
780
August1st to 15thNight
90%
717
37%
1790
25%
713
90%
713
74%
844
August16th to endNight
90%
764
43%
1910
29%
764
90%
764
75%
898
September1st to 15thNight
87%
720
40%
1868
31%
720
89%
720
72%
858
September16th to endNight
82%
716
49%
1980
41%
716
89%
716
81%
800
October1st to 15thNight
67%
720
38%
1980
30%
720
75%
720
60%
952
October16th to endNight
71%
768
42%
2329
38%
768
79%
768
58%
1039
November1st to 15thNight
65%
760
33%
2470
30%
760
74%
760
50%
1149
November16th to endNight
63%
780
36%
2535
36%
780
70%
780
43%
1258
December1st to 15thNight
52%
780
31%
2535
26%
780
62%
780
37%
1361
December16th to endNight
46%
832
33%
2704
26%
832
58%
832
32%
1490

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
4313313346%64%
49602
Night
3413313345%65%
49197
TransparencyDay
20%35%15%27%28%
49300
Night
20%25%14%27%29%
49000
SeeingDay
6%13%34%32%9%3
6492
Night
5%6%19%30%29%8%
16761

By Month

Percentage Cloud Cover SW (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
8%5%1432336%8%53%
1746
16th to endDay
8%7%14423346%52%
2051
February1st to 15thDay
6%5%24313446%56%
1901
16th to endDay
9%9%34423336%48%
1709
March1st to 15thDay
5%6%133145%48%54%
1904
16th to endDay
45%24424447%54%
2184
April1st to 15thDay
7%6%23313346%56%
2149
16th to endDay
331321235%8%63%
2160
May1st to 15thDay
221332235%7%64%
2310
16th to endDay
221312347%68%
2429
June1st to 15thDay
1212113245%73%
2340
16th to endDay
11111111284%
2402
July1st to 15thDay
2112323347%68%
2385
16th to endDay
221332446%8%60%
2435
August1st to 15thDay
111213335%74%
2160
16th to endDay
11231334473%
2292
September1st to 15thDay
212223346%70%
2091
16th to endDay
11121223378%
1980
October1st to 15thDay
331221234468%
1980
16th to endDay
222212345%71%
1893
November1st to 15thDay
4414312345%63%
1719
16th to endDay
6%313424347%58%
1755
December1st to 15thDay
5%5%24435%46%8%49%
1755
16th to endDay
10%5%34323435%52%
1872
January1st to 15thNight
7%6%2432336%6%54%
2522
16th to endNight
8%7%2442335%5%53%
2524
February1st to 15thNight
6%8%13313347%55%
2281
16th to endNight
8%10%24423446%48%
2051
March1st to 15thNight
48%1343445%7%52%
2292
16th to endNight
37%2432345%7%55%
2037
April1st to 15thNight
47%1241245%6%58%
1799
16th to endNight
2313314346%66%
1800
May1st to 15thNight
122223347%68%
1640
16th to endNight
21221335%6%70%
1684
June1st to 15thNight
11112245%77%
1620
16th to endNight
11111288%
1544
July1st to 15thNight
111122223476%
1561
16th to endNight
1212223346%67%
1731
August1st to 15thNight
121123480%
1800
16th to endNight
11111112382%
1910
September1st to 15thNight
11212235%78%
1868
16th to endNight
111112385%
1980
October1st to 15thNight
331321233470%
1980
16th to endNight
121221343473%
2329
November1st to 15thNight
2423223335%65%
2470
16th to endNight
25%14324347%58%
2535
December1st to 15thNight
7%6%2442335%8%52%
2535
16th to endNight
9%6%35%323445%51%
2704

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
26%37%16%26%19%
1747
16th to endDay
31%35%15%22%20%
2051
February1st to 15thDay
26%4416%26%21%
1901
16th to endDay
35%36%16%26%13%
1709
March1st to 15thDay
26%26%19%26%17%
1904
16th to endDay
27%38%20%26%13%
2184
April1st to 15thDay
27%26%21%30%10%
2149
16th to endDay
16%48%21%31%18%
2160
May1st to 15thDay
17%26%20%31%20%
2310
16th to endDay
14%38%22%35%16%
2432
June1st to 15thDay
12%25%12%29%37%
2340
16th to endDay
9%13419%62%
2402
July1st to 15thDay
15%3410%20%44%
2246
16th to endDay
20%5%7%17%22%26%
2282
August1st to 15thDay
12%4310%23%44%
2146
16th to endDay
15%339%35%32%
2292
September1st to 15thDay
14%448%30%36%
2091
16th to endDay
11%1210%31%42%
1980
October1st to 15thDay
18%1413%27%34%
1980
16th to endDay
13%35%11%28%37%
1893
November1st to 15thDay
22%15%15%30%24%
1719
16th to endDay
25%25%13%26%26%
1755
December1st to 15thDay
30%37%16%20%22%
1755
16th to endDay
33%25%17%22%17%
1872
January1st to 15thNight
28%35%14%24%22%
2522
16th to endNight
31%26%13%21%24%
2524
February1st to 15thNight
26%45%14%24%24%
2292
16th to endNight
33%26%13%24%18%
2051
March1st to 15thNight
29%36%16%23%21%
2292
16th to endNight
25%28%19%28%15%
2037
April1st to 15thNight
22%47%22%28%14%
1799
16th to endNight
16%37%18%36%18%
1800
May1st to 15thNight
13%36%21%35%20%
1641
16th to endNight
13%37%20%37%18%
1685
June1st to 15thNight
9%15%13%27%42%
1620
16th to endNight
6%26%21%63%
1544
July1st to 15thNight
12%338%20%51%
1471
16th to endNight
16%47%18%25%27%
1621
August1st to 15thNight
8%2314%26%44%
1790
16th to endNight
9%2211%34%39%
1910
September1st to 15thNight
10%2411%30%40%
1868
16th to endNight
6%112%34%43%
1980
October1st to 15thNight
17%1413%30%32%
1980
16th to endNight
14%25%7%28%41%
2329
November1st to 15thNight
20%1412%32%28%
2470
16th to endNight
23%3413%25%29%
2535
December1st to 15thNight
30%26%13%22%25%
2535
16th to endNight
31%27%13%24%20%
2704

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
23%14%21%24%13%2
135
16th to endDay
13%18%24%30%9%2
323
February1st to 15thDay
7%20%27%28%12%3
326
16th to endDay
15%24%30%22%7%
290
March1st to 15thDay
12%18%38%20%8%1
312
16th to endDay
9%25%35%22%7%
288
April1st to 15thDay
14%24%37%15%6%1
269
16th to endDay
7%30%38%18%21
270
May1st to 15thDay
6%20%40%24%42
288
16th to endDay
416%43%28%42
330
June1st to 15thDay
211%46%30%5%3
315
16th to endDay
4439%37%10%4
315
July1st to 15thDay
3227%47%11%6%
305
16th to endDay
4120%54%11%8%
327
August1st to 15thDay
2433%43%7%6%
315
16th to endDay
2129%49%12%5%
332
September1st to 15thDay
3444%35%11%1
315
16th to endDay
29%37%39%8%1
315
October1st to 15thDay
5%13%41%30%8%1
315
16th to endDay
49%29%34%18%3
258
November1st to 15thDay
5%8%30%29%22%3
135
16th to endDay
5%16%26%28%20%2
135
December1st to 15thDay
5%11%32%30%17%2
135
16th to endDay
9%13%26%29%16%4
144
January1st to 15thNight
9%7%24%30%19%8%
780
16th to endNight
9%8%23%28%23%5%
832
February1st to 15thNight
9%7%23%31%20%7%
764
16th to endNight
11%12%27%25%18%4
684
March1st to 15thNight
7%10%24%31%20%5%
764
16th to endNight
5%11%23%33%19%6%
768
April1st to 15thNight
6%15%28%27%16%5%
719
16th to endNight
312%28%28%20%7%
720
May1st to 15thNight
19%22%39%20%5%
561
16th to endNight
17%29%30%26%4
563
June1st to 15thNight
1220%44%27%3
540
16th to endNight
15%46%32%3
464
July1st to 15thNight
1433%50%9%
451
16th to endNight
25%27%53%9%
594
August1st to 15thNight
1327%52%14%
717
16th to endNight
3421%52%18%
764
September1st to 15thNight
25%27%48%16%
720
16th to endNight
1112%28%41%14%
716
October1st to 15thNight
3419%31%32%8%
720
16th to endNight
25%16%27%32%15%
768
November1st to 15thNight
3420%33%28%9%
760
16th to endNight
5%5%19%31%27%10%
780
December1st to 15thNight
9%7%25%30%21%6%
780
16th to endNight
11%12%23%26%19%6%
832
Page generated at 2018-03-12 10:28:02. Version ac04

Copyright 2018 A. Danko


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