West Delray Regional Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the West Delray Regional Park clear sky chart from 2005-11-05 to 2017-09-22.

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
65%
16277
18%
46986
15%
16240
68%
16240
29%
30317

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
56%
716
16%
2327
13%
716
61%
716
25%
1454
January16th to endNight
56%
768
23%
2490
20%
768
63%
768
31%
1451
February1st to 15thNight
56%
701
25%
2097
22%
700
61%
700
35%
1233
February16th to endNight
62%
631
29%
1735
21%
631
69%
631
39%
1011
March1st to 15thNight
58%
720
26%
1980
17%
720
64%
720
40%
1154
March16th to endNight
65%
768
25%
2112
21%
768
68%
768
39%
1231
April1st to 15thNight
73%
718
23%
1967
20%
718
75%
718
47%
1073
April16th to endNight
68%
720
23%
1800
15%
720
70%
720
40%
1091
May1st to 15thNight
74%
719
24%
1800
16%
719
76%
719
47%
1039
May16th to endNight
72%
607
15%
1728
13%
607
72%
607
28%
1154
June1st to 15thNight
65%
540
9%
1620
8%
540
65%
540
18%
1209
June16th to endNight
78%
540
9%
1620
8%
540
78%
540
23%
1119
July1st to 15thNight
70%
510
5%
1530
5%
510
70%
510
19%
1116
July16th to endNight
79%
564
9%
1595
9%
531
80%
531
27%
1069
August1st to 15thNight
78%
614
7%
1684
6%
611
77%
611
29%
1119
August16th to endNight
71%
764
6%
1991
5%
764
71%
764
21%
1486
September1st to 15thNight
66%
720
4%
1980
4%
720
66%
720
17%
1509
September16th to endNight
60%
685
6%
1892
6%
685
60%
685
14%
1495
October1st to 15thNight
69%
660
17%
1928
20%
660
70%
660
25%
1311
October16th to endNight
56%
704
17%
2112
18%
704
59%
704
24%
1429
November1st to 15thNight
65%
700
26%
2101
24%
700
69%
700
34%
1266
November16th to endNight
55%
720
23%
2160
20%
720
61%
720
25%
1418
December1st to 15thNight
60%
720
21%
2241
19%
720
63%
720
26%
1440
December16th to endNight
65%
768
22%
2496
22%
768
69%
768
31%
1440

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
8%6%37%8%5%7%7%7%9%28%
47880
Night
6%425%5%36%6%7%10%39%
47187
TransparencyDay
46%10%14%16%9%2
47581
Night
36%8%18%21%11%3
46990
SeeingDay
9%210%22%28%28%
6088
Night
8%211%29%33%14%
16287

By Month

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
10%6%37%7%46%6%6%9%31%
1611
16th to endDay
8%6%37%6%36%5%6%9%35%
1731
February1st to 15thDay
10%6%26%5%35%47%9%37%
1762
16th to endDay
6%5%246%36%5%6%9%42%
1738
March1st to 15thDay
5%425%7%47%6%7%10%37%
1980
16th to endDay
6%436%7%47%6%7%10%36%
2111
April1st to 15thDay
5%4346%45%8%7%11%38%
1978
16th to endDay
7%426%6%47%6%8%9%35%
2160
May1st to 15thDay
3325%5%47%6%7%11%41%
2152
16th to endDay
9%6%47%8%5%8%8%8%9%22%
2392
June1st to 15thDay
12%7%410%9%5%8%8%8%8%16%
2340
16th to endDay
8%6%48%9%6%9%8%8%11%18%
2340
July1st to 15thDay
8%7%49%9%6%9%8%9%9%18%
2340
16th to endDay
7%7%48%9%5%9%8%9%10%20%
2465
August1st to 15thDay
8%5%38%9%5%8%9%9%12%19%
2252
16th to endDay
9%6%38%9%5%7%8%9%10%19%
2205
September1st to 15thDay
9%6%38%11%6%9%9%9%9%15%
1980
16th to endDay
11%9%410%10%6%9%8%7%8%13%
1881
October1st to 15thDay
7%7%38%9%6%7%7%8%10%22%
1701
16th to endDay
12%7%37%8%5%6%6%6%9%26%
1760
November1st to 15thDay
8%436%7%47%6%7%8%36%
1757
16th to endDay
10%5%37%7%47%6%6%7%32%
1800
December1st to 15thDay
11%7%47%7%35%5%5%7%33%
1716
16th to endDay
6%6%26%6%37%5%8%10%35%
1728
January1st to 15thNight
8%5%25%5%35%7%7%10%37%
2327
16th to endNight
5%5%25%5%36%5%7%10%44%
2490
February1st to 15thNight
9%425%5%24447%49%
2090
16th to endNight
4214426%5%7%8%50%
1735
March1st to 15thNight
43245%36%5%5%8%50%
1980
16th to endNight
5%323436%5%6%9%50%
2112
April1st to 15thNight
3113425%5%6%10%55%
1967
16th to endNight
5%423435%7%6%9%47%
1800
May1st to 15thNight
3314325%5%5%9%55%
1799
16th to endNight
6%5%35%5%47%7%9%11%34%
1728
June1st to 15thNight
10%6%37%7%37%8%8%12%24%
1620
16th to endNight
5%325%6%47%8%10%12%31%
1620
July1st to 15thNight
6%5%46%7%36%7%8%11%31%
1620
16th to endNight
4326%5%47%6%7%12%38%
1703
August1st to 15thNight
4425%436%6%8%14%37%
1695
16th to endNight
7%5%36%6%37%7%9%12%29%
1991
September1st to 15thNight
6%5%36%7%5%8%9%8%13%24%
1980
16th to endNight
8%6%38%9%5%8%7%10%10%21%
1892
October1st to 15thNight
7%425%7%36%7%7%11%34%
1928
16th to endNight
12%6%25%6%35%5%7%8%34%
2112
November1st to 15thNight
6%5%245%25%5%6%11%42%
2101
16th to endNight
10%5%36%5%45%5%5%9%38%
2160
December1st to 15thNight
7%5%35%6%35%6%6%10%38%
2241
16th to endNight
5%3245%35%6%7%10%43%
2496

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
46%7%10%17%13%4
1612
16th to endDay
42%6%9%19%15%5%
1731
February1st to 15thDay
41%5%7%22%15%6%
1764
16th to endDay
36%5%12%23%15%6%
1738
March1st to 15thDay
37%6%12%25%15%3
1980
16th to endDay
37%7%12%21%14%5%
2112
April1st to 15thDay
34%8%15%22%16%2
1978
16th to endDay
38%8%9%21%17%3
2160
May1st to 15thDay
34%7%12%24%15%5%
2152
16th to endDay
49%11%13%18%7%
2396
June1st to 15thDay
59%12%13%10%4
2340
16th to endDay
51%15%20%11%1
2340
July1st to 15thDay
50%18%20%8%
2201
16th to endDay
48%16%24%10%
2310
August1st to 15thDay
47%14%25%11%1
2239
16th to endDay
51%15%21%10%
2205
September1st to 15thDay
55%16%19%7%1
1980
16th to endDay
63%13%11%6%3
1881
October1st to 15thDay
49%13%11%16%7%1
1701
16th to endDay
51%7%8%14%12%4
1760
November1st to 15thDay
41%6%9%19%17%5%
1757
16th to endDay
46%6%8%13%17%6%
1800
December1st to 15thDay
47%7%10%17%14%2
1716
16th to endDay
40%6%11%20%17%3
1728
January1st to 15thNight
39%7%16%22%11%2
2327
16th to endNight
33%6%15%25%14%5%
2490
February1st to 15thNight
33%49%27%17%6%
2099
16th to endNight
28%6%14%27%17%5%
1735
March1st to 15thNight
29%5%13%28%17%4
1980
16th to endNight
29%5%16%27%16%4
2112
April1st to 15thNight
21%6%20%30%17%2
1967
16th to endNight
29%6%16%24%19%4
1800
May1st to 15thNight
24%5%15%34%15%5%
1800
16th to endNight
39%7%19%26%6%
1730
June1st to 15thNight
47%13%20%15%3
1620
16th to endNight
37%15%31%13%1
1620
July1st to 15thNight
43%15%29%10%
1530
16th to endNight
32%15%34%15%1
1595
August1st to 15thNight
32%14%35%16%1
1684
16th to endNight
41%17%28%11%1
1991
September1st to 15thNight
46%16%25%10%1
1980
16th to endNight
51%15%19%9%3
1892
October1st to 15thNight
42%8%17%18%11%1
1928
16th to endNight
45%5%12%19%12%4
2112
November1st to 15thNight
35%412%23%18%5%
2101
16th to endNight
43%49%19%14%8%
2160
December1st to 15thNight
40%6%13%20%15%2
2241
16th to endNight
34%5%15%24%17%3
2496

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%5%21%28%22%
90
16th to endDay
15%10%21%35%11%5%
96
February1st to 15thDay
9%224%38%16%7%
103
16th to endDay
8%5%21%36%26%1
239
March1st to 15thDay
4125%39%24%4
270
16th to endDay
5%319%38%25%7%
288
April1st to 15thDay
3217%34%29%12%
270
16th to endDay
5%12%33%31%15%
270
May1st to 15thDay
410%26%36%21%
288
16th to endDay
8%1417%35%32%
331
June1st to 15thDay
13%6%16%29%33%
315
16th to endDay
5%116%30%53%
315
July1st to 15thDay
6%6%29%56%
305
16th to endDay
6%37%22%59%
326
August1st to 15thDay
8%11426%56%
313
16th to endDay
11%329%24%49%
332
September1st to 15thDay
8%137%22%55%
315
16th to endDay
11%226%27%49%
278
October1st to 15thDay
10%323%40%20%
255
16th to endDay
14%317%26%23%15%
272
November1st to 15thDay
10%112%32%29%12%
265
16th to endDay
9%219%35%29%3
270
December1st to 15thDay
16%215%30%29%6%
186
16th to endDay
11%16%44%29%7%
96
January1st to 15thNight
11%417%36%27%2
720
16th to endNight
7%423%41%22%1
768
February1st to 15thNight
11%320%43%20%1
704
16th to endNight
5%322%45%22%
631
March1st to 15thNight
6%324%39%23%3
720
16th to endNight
5%218%47%24%2
768
April1st to 15thNight
4112%47%30%3
718
16th to endNight
7%113%43%31%2
720
May1st to 15thNight
418%45%37%2
720
16th to endNight
7%2430%40%13%
609
June1st to 15thNight
10%2217%42%24%
540
16th to endNight
419%42%41%
540
July1st to 15thNight
7%15%44%40%
510
16th to endNight
415%39%48%
564
August1st to 15thNight
7%5%44%39%
614
16th to endNight
10%210%40%35%
764
September1st to 15thNight
8%139%38%38%
720
16th to endNight
13%29%40%33%
685
October1st to 15thNight
9%15%27%43%12%
660
16th to endNight
18%111%28%30%10%
704
November1st to 15thNight
8%116%35%33%5%
700
16th to endNight
12%316%37%27%3
720
December1st to 15thNight
11%314%38%28%3
720
16th to endNight
7%314%34%35%5%
768
Page generated at 2017-09-23 06:43:45. Version ac04

Copyright 2017 A. Danko


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