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 2019-06-19.

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
66%
18682
18%
53976
16%
18645
69%
18645
30%
34320

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%
836
20%
2717
17%
836
63%
836
27%
1649
January16th to endNight
54%
896
21%
2905
18%
896
61%
896
29%
1733
February1st to 15thNight
60%
821
26%
2455
23%
820
65%
820
36%
1422
February16th to endNight
66%
735
29%
2021
23%
735
71%
735
41%
1160
March1st to 15thNight
58%
840
27%
2310
19%
840
65%
840
42%
1308
March16th to endNight
66%
896
26%
2464
22%
896
69%
896
41%
1415
April1st to 15thNight
75%
838
25%
2296
22%
838
77%
838
48%
1242
April16th to endNight
70%
831
23%
2077
16%
831
72%
831
42%
1233
May1st to 15thNight
73%
839
22%
2100
15%
839
75%
839
44%
1244
May16th to endNight
71%
711
16%
2024
13%
711
71%
711
28%
1356
June1st to 15thNight
68%
630
10%
1890
8%
630
68%
630
20%
1384
June16th to endNight
78%
597
9%
1791
8%
597
78%
597
22%
1259
July1st to 15thNight
72%
555
5%
1665
5%
555
72%
555
20%
1196
July16th to endNight
79%
612
9%
1739
9%
579
80%
579
28%
1157
August1st to 15thNight
78%
652
7%
1792
6%
649
78%
649
30%
1175
August16th to endNight
72%
828
6%
2158
5%
828
72%
828
22%
1583
September1st to 15thNight
66%
780
4%
2145
4%
780
66%
780
16%
1647
September16th to endNight
63%
777
6%
2145
6%
777
63%
777
17%
1642
October1st to 15thNight
69%
780
17%
2278
19%
780
70%
780
25%
1550
October16th to endNight
59%
832
18%
2496
18%
832
62%
832
26%
1648
November1st to 15thNight
67%
820
25%
2461
24%
820
71%
820
34%
1462
November16th to endNight
57%
840
23%
2520
21%
840
62%
840
26%
1636
December1st to 15thNight
61%
840
24%
2615
21%
840
66%
840
29%
1611
December16th to endNight
68%
896
23%
2912
24%
896
71%
896
34%
1608

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%5%37%7%47%7%8%9%29%
54726
Night
6%425%5%36%6%7%10%40%
54177
TransparencyDay
44%10%14%16%10%2
54427
Night
35%8%19%21%11%3
53980
SeeingDay
8%111%24%28%24%
8467
Night
8%211%30%33%14%
18692

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
9%6%36%6%46%6%6%9%34%
1881
16th to endDay
8%6%27%6%46%6%7%9%35%
2019
February1st to 15thDay
9%5%26%5%35%5%7%9%38%
2064
16th to endDay
6%4246%36%5%6%9%43%
2024
March1st to 15thDay
5%425%6%46%6%7%10%41%
2310
16th to endDay
6%425%7%46%6%7%9%38%
2463
April1st to 15thDay
5%4245%45%8%8%10%39%
2309
16th to endDay
6%425%6%46%6%8%9%38%
2488
May1st to 15thDay
4426%5%47%7%7%11%38%
2512
16th to endDay
10%6%48%8%5%7%7%7%8%25%
2800
June1st to 15thDay
11%7%310%10%5%9%8%8%8%17%
2730
16th to endDay
8%5%48%9%5%9%8%9%11%19%
2577
July1st to 15thDay
8%6%38%8%6%9%8%9%10%19%
2535
16th to endDay
7%6%37%9%5%9%8%9%10%21%
2673
August1st to 15thDay
8%5%37%8%5%8%9%9%13%20%
2396
16th to endDay
8%6%38%10%5%8%8%9%11%19%
2390
September1st to 15thDay
9%6%38%11%6%9%10%9%9%15%
2145
16th to endDay
11%8%410%10%6%9%8%7%8%14%
2145
October1st to 15thDay
6%7%38%9%6%8%8%9%9%21%
2010
16th to endDay
11%7%27%7%5%6%6%7%9%28%
2080
November1st to 15thDay
7%436%6%47%7%8%8%36%
2057
16th to endDay
9%5%37%7%47%6%6%7%34%
2100
December1st to 15thDay
10%7%36%6%35%5%5%8%36%
2002
16th to endDay
5%6%25%5%37%6%8%11%37%
2016
January1st to 15thNight
7%5%25%5%35%6%7%9%40%
2717
16th to endNight
5%5%25%5%36%6%7%10%42%
2905
February1st to 15thNight
8%4245%245%5%8%49%
2448
16th to endNight
4214425%5%7%8%51%
2021
March1st to 15thNight
33245%35%5%5%8%53%
2310
16th to endNight
5%313435%5%6%9%52%
2464
April1st to 15thNight
3113325%5%6%10%55%
2296
16th to endNight
5%413425%6%6%9%50%
2077
May1st to 15thNight
4313325%5%6%10%51%
2099
16th to endNight
6%5%36%5%46%6%8%10%35%
2024
June1st to 15thNight
9%5%37%7%37%8%8%12%27%
1890
16th to endNight
5%325%6%47%8%10%12%31%
1791
July1st to 15thNight
5%5%46%7%36%7%8%12%32%
1755
16th to endNight
4326%5%47%6%8%12%38%
1847
August1st to 15thNight
4425%436%6%9%15%38%
1803
16th to endNight
6%5%36%6%37%7%10%12%30%
2158
September1st to 15thNight
6%5%35%8%5%8%10%9%13%23%
2145
16th to endNight
7%5%37%9%47%7%9%10%25%
2145
October1st to 15thNight
7%5%25%7%46%8%7%12%32%
2278
16th to endNight
11%6%25%6%35%5%7%8%37%
2496
November1st to 15thNight
5%4245%35%5%7%11%42%
2461
16th to endNight
9%5%36%5%45%6%6%9%38%
2520
December1st to 15thNight
6%425%6%36%6%6%10%42%
2615
16th to endNight
5%3245%35%6%7%11%45%
2912

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
43%6%10%18%15%4
1882
16th to endDay
42%6%10%20%14%5%
2019
February1st to 15thDay
39%6%10%24%14%5%
2066
16th to endDay
34%6%11%23%18%6%
2024
March1st to 15thDay
34%6%13%25%15%4
2310
16th to endDay
36%6%12%22%15%5%
2464
April1st to 15thDay
33%8%16%22%16%2
2309
16th to endDay
35%8%10%23%18%3
2488
May1st to 15thDay
36%8%13%23%13%5%
2512
16th to endDay
49%10%11%17%11%
2804
June1st to 15thDay
57%13%14%10%3
2730
16th to endDay
50%16%20%11%1
2577
July1st to 15thDay
49%18%22%8%
2396
16th to endDay
47%16%25%10%
2518
August1st to 15thDay
45%14%26%11%1
2383
16th to endDay
50%15%22%9%
2390
September1st to 15thDay
54%17%19%6%
2145
16th to endDay
60%14%13%8%3
2145
October1st to 15thDay
49%12%12%16%7%1
2010
16th to endDay
48%8%8%15%13%5%
2080
November1st to 15thDay
39%7%11%20%16%4
2057
16th to endDay
45%7%9%15%16%5%
2100
December1st to 15thDay
43%7%10%20%14%3
2002
16th to endDay
36%6%12%24%16%2
2016
January1st to 15thNight
36%6%15%23%14%3
2717
16th to endNight
34%6%15%24%13%5%
2905
February1st to 15thNight
31%412%29%15%5%
2457
16th to endNight
27%6%13%27%20%5%
2021
March1st to 15thNight
27%415%29%17%5%
2310
16th to endNight
27%5%15%28%18%5%
2464
April1st to 15thNight
21%6%20%31%17%2
2296
16th to endNight
28%5%16%25%19%5%
2077
May1st to 15thNight
26%6%17%31%14%4
2100
16th to endNight
40%7%16%24%10%
2026
June1st to 15thNight
44%13%22%15%3
1890
16th to endNight
37%17%29%13%1
1791
July1st to 15thNight
41%15%30%11%
1665
16th to endNight
32%15%35%15%1
1739
August1st to 15thNight
30%14%36%16%1
1792
16th to endNight
39%17%31%10%1
2158
September1st to 15thNight
45%18%25%9%1
2145
16th to endNight
48%14%21%11%3
2145
October1st to 15thNight
42%8%19%18%9%1
2278
16th to endNight
42%5%12%19%14%5%
2496
November1st to 15thNight
33%5%14%24%16%4
2461
16th to endNight
42%5%10%19%15%7%
2520
December1st to 15thNight
37%6%13%21%16%3
2615
16th to endNight
30%5%15%28%17%3
2912

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
16%424%34%19%1
180
16th to endDay
13%6%35%31%9%3
192
February1st to 15thDay
10%116%43%21%6%
195
16th to endDay
7%416%35%32%4
343
March1st to 15thDay
4127%41%22%3
390
16th to endDay
5%322%37%24%6%
416
April1st to 15thDay
4219%34%28%10%
390
16th to endDay
4114%35%30%13%
379
May1st to 15thDay
6%10%31%34%17%
408
16th to endDay
13%1419%32%28%
459
June1st to 15thDay
12%5%16%30%33%
435
16th to endDay
6%116%30%53%
388
July1st to 15thDay
5%6%30%55%
365
16th to endDay
6%28%25%56%
390
August1st to 15thDay
7%116%29%53%
358
16th to endDay
10%219%28%47%
396
September1st to 15thDay
9%137%25%52%
375
16th to endDay
10%117%32%44%
374
October1st to 15thDay
10%15%26%37%17%
375
16th to endDay
11%316%31%24%13%
400
November1st to 15thDay
8%110%35%32%12%
385
16th to endDay
8%220%38%26%2
390
December1st to 15thDay
11%218%34%27%5%
292
16th to endDay
6%39%41%30%8%
192
January1st to 15thNight
10%418%36%27%2
840
16th to endNight
8%325%41%20%1
896
February1st to 15thNight
10%318%43%22%1
824
16th to endNight
5%219%43%28%
735
March1st to 15thNight
5%324%40%23%2
840
16th to endNight
6%217%47%24%1
896
April1st to 15thNight
4112%47%31%4
838
16th to endNight
7%113%44%31%2
831
May1st to 15thNight
6%18%43%37%2
840
16th to endNight
8%2429%41%13%
713
June1st to 15thNight
10%2215%44%25%
630
16th to endNight
418%41%43%
597
July1st to 15thNight
6%15%42%43%
555
16th to endNight
415%39%48%
612
August1st to 15thNight
7%5%45%40%
652
16th to endNight
9%29%40%37%
828
September1st to 15thNight
8%129%39%37%
780
16th to endNight
12%29%40%34%
777
October1st to 15thNight
9%15%27%43%12%
780
16th to endNight
16%110%29%32%9%
832
November1st to 15thNight
7%114%33%36%5%
820
16th to endNight
11%316%39%26%3
840
December1st to 15thNight
10%315%38%29%3
840
16th to endNight
6%213%34%35%6%
896
Page generated at 2019-06-20 08:02:27. Version ac04

Copyright 2019 A. Danko


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