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 2017-05-01.

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
63%
15820
16%
45616
14%
15780
66%
15780
26%
30368

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
54%
716
15%
2327
12%
716
59%
716
23%
1503
January16th to endNight
55%
768
22%
2487
18%
768
62%
768
29%
1474
February1st to 15thNight
54%
703
25%
2084
20%
699
60%
699
34%
1242
February16th to endNight
59%
631
27%
1735
19%
631
66%
631
36%
1045
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%
663
23%
1659
16%
663
76%
663
43%
992
May16th to endNight
67%
573
11%
1599
10%
573
67%
573
24%
1137
June1st to 15thNight
64%
495
8%
1485
7%
495
64%
495
16%
1126
June16th to endNight
78%
495
7%
1485
6%
495
78%
495
20%
1060
July1st to 15thNight
68%
465
6%
1395
6%
465
68%
465
14%
1079
July16th to endNight
81%
522
8%
1469
8%
489
82%
489
26%
997
August1st to 15thNight
75%
574
7%
1554
6%
571
75%
571
25%
1083
August16th to endNight
68%
700
5%
1826
4%
700
68%
700
18%
1392
September1st to 15thNight
67%
660
4%
1815
3%
660
67%
660
13%
1438
September16th to endNight
57%
657
5%
1815
5%
657
57%
657
12%
1499
October1st to 15thNight
65%
660
13%
1930
15%
660
66%
660
19%
1388
October16th to endNight
54%
704
16%
2112
16%
704
56%
704
21%
1496
November1st to 15thNight
61%
700
23%
2101
21%
700
66%
700
29%
1317
November16th to endNight
55%
720
21%
2160
18%
720
60%
720
25%
1427
December1st to 15thNight
57%
720
19%
2223
18%
720
61%
720
23%
1474
December16th to endNight
64%
768
21%
2496
21%
768
68%
768
29%
1509

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%
46125
Night
6%5%25%6%36%6%7%10%37%
45820
TransparencyDay
46%12%15%14%9%2
45827
Night
37%11%18%19%11%2
45622
SeeingDay
9%112%24%26%24%
5548
Night
8%214%31%31%12%
15828

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%38%7%47%6%7%9%29%
1611
16th to endDay
8%6%36%6%35%6%8%9%35%
1734
February1st to 15thDay
10%6%35%5%46%46%9%37%
1770
16th to endDay
7%325%6%46%5%7%9%41%
1738
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
3335%6%47%7%9%11%37%
1974
16th to endDay
9%7%49%8%5%7%8%9%9%20%
2170
June1st to 15thDay
11%7%410%10%6%9%8%7%7%15%
2145
16th to endDay
6%8%48%9%6%10%9%9%11%15%
2145
July1st to 15thDay
7%8%48%9%6%9%8%10%11%16%
2145
16th to endDay
5%5%38%9%6%8%9%10%13%20%
2283
August1st to 15thDay
6%7%38%9%5%8%9%11%12%17%
2052
16th to endDay
8%6%29%8%6%9%9%11%12%15%
2020
September1st to 15thDay
6%5%411%12%6%11%11%8%9%12%
1815
16th to endDay
11%10%411%10%7%9%7%7%7%12%
1815
October1st to 15thDay
7%7%39%10%5%8%8%11%10%18%
1700
16th to endDay
14%7%37%7%47%6%6%8%27%
1760
November1st to 15thDay
8%6%37%7%46%6%7%9%33%
1757
16th to endDay
10%5%37%8%5%6%6%7%7%31%
1800
December1st to 15thDay
11%6%38%8%47%5%6%7%30%
1734
16th to endDay
7%6%26%6%46%6%9%11%32%
1728
January1st to 15thNight
8%5%35%6%36%6%7%10%35%
2327
16th to endNight
5%5%25%435%6%6%10%44%
2487
February1st to 15thNight
9%5%2433347%9%46%
2080
16th to endNight
5%215%435%5%6%9%48%
1735
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
3414325%5%8%9%52%
1659
16th to endNight
8%5%37%5%38%7%9%11%30%
1598
June1st to 15thNight
10%5%38%7%5%7%7%9%10%23%
1485
16th to endNight
4425%6%5%7%9%9%13%30%
1485
July1st to 15thNight
5%6%47%8%5%8%6%8%10%28%
1485
16th to endNight
33246%46%8%7%12%39%
1577
August1st to 15thNight
44246%37%8%9%15%34%
1565
16th to endNight
6%427%7%47%8%10%13%27%
1826
September1st to 15thNight
5%5%46%9%5%9%9%10%12%21%
1815
16th to endNight
8%7%39%9%6%8%9%8%8%19%
1815
October1st to 15thNight
6%6%37%7%5%7%8%8%12%27%
1930
16th to endNight
12%8%36%6%36%6%6%8%31%
2112
November1st to 15thNight
6%5%25%6%35%5%6%11%40%
2101
16th to endNight
9%6%26%6%36%6%6%7%36%
2160
December1st to 15thNight
9%5%36%5%45%5%8%9%35%
2223
16th to endNight
6%425%5%35%6%7%9%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%8%12%15%11%4
1612
16th to endDay
40%8%13%18%14%5%
1734
February1st to 15thDay
40%5%10%21%15%5%
1773
16th to endDay
35%7%12%23%14%5%
1738
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
34%7%17%23%13%4
1974
16th to endDay
53%12%14%14%5%
2174
June1st to 15thDay
60%12%12%10%3
2145
16th to endDay
54%18%17%8%
2145
July1st to 15thDay
53%20%20%5%
2006
16th to endDay
46%20%24%8%
2128
August1st to 15thDay
47%20%22%7%
2039
16th to endDay
52%19%22%5%
2020
September1st to 15thDay
57%20%15%5%1
1815
16th to endDay
65%14%12%42
1815
October1st to 15thDay
50%13%15%12%7%
1700
16th to endDay
50%8%10%15%11%4
1760
November1st to 15thDay
42%8%12%15%16%4
1757
16th to endDay
47%7%10%12%16%6%
1800
December1st to 15thDay
48%8%10%16%13%2
1734
16th to endDay
40%8%12%20%16%2
1728
January1st to 15thNight
40%8%17%19%10%2
2327
16th to endNight
32%8%17%22%14%5%
2487
February1st to 15thNight
32%5%12%26%16%6%
2088
16th to endNight
29%8%13%26%16%5%
1735
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
25%8%15%32%14%3
1660
16th to endNight
42%11%18%21%6%
1600
June1st to 15thNight
49%13%20%12%4
1485
16th to endNight
38%17%29%12%1
1485
July1st to 15thNight
47%18%23%9%
1395
16th to endNight
32%17%33%14%2
1469
August1st to 15thNight
34%17%32%15%
1554
16th to endNight
42%20%25%11%1
1826
September1st to 15thNight
46%21%22%8%1
1815
16th to endNight
55%17%15%8%2
1815
October1st to 15thNight
44%13%16%14%9%1
1930
16th to endNight
47%8%12%16%11%3
2112
November1st to 15thNight
37%6%12%20%18%5%
2101
16th to endNight
41%7%12%16%14%7%
2160
December1st to 15thNight
41%9%14%17%15%2
2223
16th to endNight
34%8%13%22%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
20%5%25%32%16%
90
16th to endDay
15%9%23%36%10%4
96
February1st to 15thDay
9%6%23%35%19%5%
112
16th to endDay
8%228%35%23%1
239
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
419%27%37%19%
229
16th to endDay
7%17%17%33%31%
267
June1st to 15thDay
9%5%20%28%34%
255
16th to endDay
5%37%27%55%
255
July1st to 15thDay
6%28%28%53%
245
16th to endDay
4211%27%53%
270
August1st to 15thDay
7%5%9%21%55%
253
16th to endDay
12%212%24%47%
268
September1st to 15thDay
7%114%21%53%
255
16th to endDay
15%1210%26%42%
254
October1st to 15thDay
9%8%27%35%18%
255
16th to endDay
14%219%27%23%12%
272
November1st to 15thDay
9%112%34%30%10%
265
16th to endDay
9%222%33%28%2
270
December1st to 15thDay
18%119%31%24%4
204
16th to endDay
8%14%36%35%5%
96
January1st to 15thNight
10%5%20%35%26%2
720
16th to endNight
6%426%41%19%1
768
February1st to 15thNight
10%326%39%18%
704
16th to endNight
6%324%47%18%
631
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
4111%44%34%2
664
16th to endNight
9%27%30%38%11%
575
June1st to 15thNight
9%3419%39%24%
495
16th to endNight
3311%46%35%
495
July1st to 15thNight
7%210%41%36%
465
16th to endNight
319%38%46%
522
August1st to 15thNight
7%18%43%38%
574
16th to endNight
9%1313%36%36%
700
September1st to 15thNight
7%1313%38%35%
660
16th to endNight
12%414%37%29%
657
October1st to 15thNight
8%18%29%39%11%
660
16th to endNight
16%114%28%28%9%
704
November1st to 15thNight
8%119%34%29%5%
700
16th to endNight
12%220%36%23%3
720
December1st to 15thNight
9%318%38%27%2
720
16th to endNight
7%217%34%32%4
768
Page generated at 2017-05-02 08:43:38. Version ac04

Copyright 2017 A. Danko


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