Fort Lauderdale
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Lauderdale clear sky chart from 2005-11-05 to 2018-02-22.

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
64%
16923
17%
48854
14%
16883
67%
16883
26%
32358

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
52%
776
15%
2522
12%
776
58%
776
23%
1618
January16th to endNight
54%
832
21%
2694
18%
832
61%
832
28%
1633
February1st to 15thNight
57%
763
25%
2262
21%
759
63%
759
35%
1337
February16th to endNight
61%
659
29%
1812
21%
659
68%
659
37%
1081
March1st to 15thNight
58%
720
24%
1980
16%
720
65%
720
39%
1170
March16th to endNight
62%
768
23%
2112
19%
768
65%
768
37%
1278
April1st to 15thNight
70%
718
23%
1967
20%
718
73%
718
45%
1102
April16th to endNight
64%
720
22%
1800
14%
720
67%
720
37%
1140
May1st to 15thNight
74%
719
22%
1799
15%
719
76%
719
44%
1059
May16th to endNight
68%
627
14%
1749
12%
627
69%
627
26%
1222
June1st to 15thNight
62%
540
8%
1620
7%
540
62%
540
15%
1242
June16th to endNight
79%
540
8%
1620
7%
540
79%
540
20%
1157
July1st to 15thNight
70%
510
5%
1530
6%
510
70%
510
16%
1148
July16th to endNight
81%
564
9%
1595
9%
531
82%
531
26%
1074
August1st to 15thNight
76%
626
7%
1696
6%
623
76%
623
26%
1171
August16th to endNight
68%
764
6%
1993
5%
764
68%
764
18%
1513
September1st to 15thNight
67%
720
4%
1980
3%
720
67%
720
15%
1547
September16th to endNight
59%
717
6%
1980
6%
717
59%
717
12%
1622
October1st to 15thNight
65%
720
13%
2106
14%
720
65%
720
18%
1520
October16th to endNight
54%
768
16%
2304
16%
768
57%
768
21%
1633
November1st to 15thNight
62%
760
22%
2281
20%
760
66%
760
30%
1418
November16th to endNight
56%
780
22%
2340
20%
780
61%
780
25%
1537
December1st to 15thNight
58%
780
20%
2408
18%
780
63%
780
25%
1551
December16th to endNight
66%
832
24%
2704
24%
832
70%
832
31%
1585

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%8%10%26%
49378
Night
6%5%25%6%36%6%7%10%37%
49058
TransparencyDay
45%12%15%14%9%2
49080
Night
37%11%18%19%11%2
48860
SeeingDay
8%112%25%27%23%
6663
Night
8%214%30%31%13%
16931

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%47%6%7%9%30%
1746
16th to endDay
8%6%36%6%35%6%8%9%34%
1879
February1st to 15thDay
9%6%35%5%36%47%9%37%
1922
16th to endDay
7%325%6%45%5%7%9%42%
1808
March1st to 15thDay
6%325%7%47%7%8%9%36%
1980
16th to endDay
6%5%27%7%47%7%8%9%34%
2111
April1st to 15thDay
5%435%6%36%7%8%13%35%
1978
16th to endDay
6%436%6%48%7%8%10%34%
2160
May1st to 15thDay
3325%6%36%7%9%10%39%
2152
16th to endDay
8%7%48%8%5%7%8%9%9%21%
2373
June1st to 15thDay
11%7%5%10%10%6%9%8%7%7%14%
2340
16th to endDay
6%7%38%9%6%10%9%9%11%16%
2340
July1st to 15thDay
7%7%47%9%5%9%8%10%12%17%
2340
16th to endDay
5%5%38%9%6%8%9%10%12%19%
2465
August1st to 15thDay
6%6%28%8%48%9%11%12%19%
2238
16th to endDay
9%6%28%8%6%9%9%10%12%16%
2205
September1st to 15thDay
7%5%310%11%6%10%11%9%9%13%
1980
16th to endDay
11%9%411%10%7%9%7%7%7%13%
1980
October1st to 15thDay
8%6%39%10%5%8%7%11%10%17%
1854
16th to endDay
13%7%37%7%47%6%6%8%26%
1920
November1st to 15thDay
7%5%36%7%46%6%7%9%34%
1907
16th to endDay
10%5%37%8%46%6%7%7%32%
1950
December1st to 15thDay
10%6%37%7%47%5%6%7%33%
1878
16th to endDay
7%5%25%6%46%6%9%12%34%
1872
January1st to 15thNight
8%5%35%6%35%6%7%10%36%
2522
16th to endNight
5%5%25%5%35%6%7%9%42%
2694
February1st to 15thNight
8%5%243335%7%9%46%
2258
16th to endNight
5%215%435%5%6%9%49%
1812
March1st to 15thNight
4315%425%6%6%9%48%
1980
16th to endNight
5%315%5%35%6%5%11%47%
2112
April1st to 15thNight
32134245%7%11%53%
1967
16th to endNight
5%4245%35%6%7%9%45%
1800
May1st to 15thNight
2314325%5%8%9%53%
1799
16th to endNight
8%5%36%5%38%7%9%11%31%
1748
June1st to 15thNight
11%6%38%7%5%7%7%9%10%23%
1620
16th to endNight
4425%6%5%7%9%10%13%30%
1620
July1st to 15thNight
45%47%8%48%6%8%10%30%
1620
16th to endNight
33246%46%7%7%13%39%
1703
August1st to 15thNight
44146%37%7%8%15%35%
1707
16th to endNight
7%427%7%46%8%10%13%27%
1993
September1st to 15thNight
5%5%36%9%5%9%8%10%12%22%
1980
16th to endNight
8%7%38%9%6%7%8%8%9%21%
1980
October1st to 15thNight
6%6%37%7%5%7%8%8%12%26%
2106
16th to endNight
12%8%36%6%36%6%6%7%31%
2304
November1st to 15thNight
6%5%25%6%36%6%6%11%40%
2281
16th to endNight
9%6%25%6%36%6%7%7%37%
2340
December1st to 15thNight
8%5%35%5%45%5%7%9%38%
2408
16th to endNight
6%424425%6%7%11%44%
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
45%8%12%15%13%4
1747
16th to endDay
40%8%13%18%14%5%
1879
February1st to 15thDay
39%6%12%21%15%5%
1925
16th to endDay
35%7%12%22%16%5%
1808
March1st to 15thDay
36%8%16%21%14%2
1980
16th to endDay
38%8%14%19%13%5%
2112
April1st to 15thDay
33%10%17%23%13%2
1978
16th to endDay
38%8%14%19%15%3
2160
May1st to 15thDay
33%7%16%23%13%5%
2152
16th to endDay
51%12%14%16%5%
2377
June1st to 15thDay
61%13%12%9%3
2340
16th to endDay
52%19%18%8%
2340
July1st to 15thDay
51%20%21%6%
2201
16th to endDay
46%20%24%8%
2310
August1st to 15thDay
45%20%22%10%1
2225
16th to endDay
51%18%21%7%
2205
September1st to 15thDay
55%20%16%6%1
1980
16th to endDay
64%14%12%5%3
1980
October1st to 15thDay
51%13%15%11%6%
1854
16th to endDay
50%8%10%14%10%5%
1920
November1st to 15thDay
41%8%13%16%16%4
1907
16th to endDay
46%7%10%13%16%5%
1950
December1st to 15thDay
45%8%10%17%13%3
1878
16th to endDay
38%8%13%21%15%2
1872
January1st to 15thNight
40%8%17%20%11%2
2522
16th to endNight
34%8%16%21%13%4
2694
February1st to 15thNight
31%6%14%27%15%5%
2266
16th to endNight
28%8%13%25%18%5%
1812
March1st to 15thNight
28%7%15%24%18%4
1980
16th to endNight
30%7%17%24%16%4
2112
April1st to 15thNight
23%7%20%29%16%3
1967
16th to endNight
30%9%15%22%18%4
1800
May1st to 15thNight
24%8%15%31%14%5%
1800
16th to endNight
40%11%19%23%6%
1750
June1st to 15thNight
50%13%19%12%3
1620
16th to endNight
38%18%29%12%1
1620
July1st to 15thNight
44%17%26%10%
1530
16th to endNight
31%17%34%14%1
1595
August1st to 15thNight
34%16%30%17%1
1696
16th to endNight
41%19%25%12%1
1993
September1st to 15thNight
45%20%23%8%1
1980
16th to endNight
53%17%16%8%3
1980
October1st to 15thNight
45%13%17%14%8%1
2106
16th to endNight
47%8%11%16%11%4
2304
November1st to 15thNight
36%6%13%21%17%4
2281
16th to endNight
40%7%12%16%14%7%
2340
December1st to 15thNight
38%9%14%17%16%3
2408
16th to endNight
31%8%14%25%17%2
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
19%8%28%31%12%
135
16th to endDay
13%6%29%37%9%2
144
February1st to 15thDay
8%420%42%20%5%
159
16th to endDay
7%226%33%26%3
265
March1st to 15thDay
5%130%38%19%4
270
16th to endDay
8%121%39%23%4
288
April1st to 15thDay
4121%36%26%9%
270
16th to endDay
7%14%34%33%9%
270
May1st to 15thDay
4110%29%37%16%
288
16th to endDay
6%18%19%34%29%
331
June1st to 15thDay
9%18%20%28%30%
315
16th to endDay
448%30%51%
315
July1st to 15thDay
5%27%33%51%
305
16th to endDay
4211%27%53%
326
August1st to 15thDay
7%48%26%52%
313
16th to endDay
12%313%27%43%
332
September1st to 15thDay
8%213%22%52%
315
16th to endDay
14%1212%29%39%
314
October1st to 15thDay
10%9%27%35%16%
315
16th to endDay
13%319%30%21%11%
336
November1st to 15thDay
8%112%36%31%9%
325
16th to endDay
8%222%36%26%2
330
December1st to 15thDay
15%118%32%26%4
258
16th to endDay
5%11%34%38%9%
144
January1st to 15thNight
11%5%21%34%25%2
780
16th to endNight
6%427%41%18%1
832
February1st to 15thNight
9%325%41%19%
764
16th to endNight
5%323%45%21%
659
March1st to 15thNight
7%226%38%23%2
720
16th to endNight
6%221%46%22%1
768
April1st to 15thNight
3116%47%28%2
718
16th to endNight
8%117%42%28%1
720
May1st to 15thNight
411%44%35%2
720
16th to endNight
9%27%31%39%11%
629
June1st to 15thNight
11%2418%38%23%
540
16th to endNight
3211%45%36%
540
July1st to 15thNight
6%210%41%38%
510
16th to endNight
318%37%48%
564
August1st to 15thNight
7%19%44%38%
626
16th to endNight
9%313%37%35%
764
September1st to 15thNight
8%1312%37%36%
720
16th to endNight
12%415%38%29%
717
October1st to 15thNight
9%18%29%39%11%
720
16th to endNight
16%114%29%28%8%
768
November1st to 15thNight
8%118%34%31%5%
760
16th to endNight
12%220%36%24%3
780
December1st to 15thNight
9%318%38%27%2
780
16th to endNight
6%216%34%34%5%
832
Page generated at 2018-02-23 11:21:32. Version ac04

Copyright 2018 A. Danko


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