Miami
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Miami 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
55%
16937
16%
48859
12%
16898
60%
16898
22%
32869

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
44%
776
15%
2522
11%
776
51%
776
19%
1660
January16th to endNight
46%
832
21%
2681
17%
832
55%
832
22%
1675
February1st to 15thNight
52%
762
24%
2258
20%
759
59%
759
29%
1365
February16th to endNight
52%
659
31%
1812
18%
659
63%
659
33%
1053
March1st to 15thNight
46%
720
23%
1980
14%
720
55%
720
27%
1252
March16th to endNight
53%
768
23%
2112
17%
768
58%
768
29%
1287
April1st to 15thNight
62%
718
23%
1973
18%
718
68%
718
38%
1116
April16th to endNight
57%
720
22%
1800
12%
720
63%
720
31%
1143
May1st to 15thNight
63%
719
22%
1799
14%
719
66%
719
39%
1058
May16th to endNight
58%
636
13%
1758
11%
636
59%
636
22%
1248
June1st to 15thNight
53%
540
8%
1620
6%
540
54%
540
12%
1272
June16th to endNight
64%
540
7%
1620
5%
540
65%
540
19%
1154
July1st to 15thNight
65%
510
5%
1530
5%
510
65%
510
17%
1126
July16th to endNight
67%
564
9%
1595
9%
531
72%
531
25%
1052
August1st to 15thNight
68%
632
8%
1702
7%
629
68%
629
22%
1185
August16th to endNight
62%
764
7%
2008
5%
764
62%
764
20%
1499
September1st to 15thNight
61%
720
4%
1980
4%
720
61%
720
16%
1538
September16th to endNight
57%
717
6%
1980
4%
717
59%
717
12%
1610
October1st to 15thNight
56%
720
10%
2101
11%
720
56%
720
15%
1569
October16th to endNight
47%
768
15%
2304
12%
768
52%
768
17%
1638
November1st to 15thNight
52%
760
19%
2281
16%
760
57%
760
21%
1531
November16th to endNight
48%
780
22%
2340
17%
780
55%
780
19%
1611
December1st to 15thNight
48%
780
19%
2399
14%
780
54%
780
20%
1620
December16th to endNight
60%
832
24%
2704
22%
832
66%
832
27%
1607

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%7%5%7%7%8%10%28%
49374
Night
6%425%6%36%6%7%10%38%
49064
TransparencyDay
41%14%17%15%9%2
49076
Night
38%10%17%19%11%2
48866
SeeingDay
9%9%10%23%27%19%
6677
Night
8%15%10%24%27%13%
16946

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%5%46%7%46%6%6%10%31%
1746
16th to endDay
8%5%25%5%46%6%8%9%35%
1892
February1st to 15thDay
9%5%25%6%36%46%10%39%
1926
16th to endDay
6%425%5%35%6%8%10%42%
1808
March1st to 15thDay
6%5%26%5%46%6%7%11%36%
1980
16th to endDay
7%435%5%45%7%8%10%37%
2111
April1st to 15thDay
4415%435%6%9%12%39%
1972
16th to endDay
7%425%5%37%7%8%12%35%
2160
May1st to 15thDay
4325%5%37%9%7%11%41%
2152
16th to endDay
9%6%47%8%5%8%8%9%10%20%
2363
June1st to 15thDay
12%7%5%9%9%7%9%7%7%8%14%
2340
16th to endDay
6%7%38%9%6%11%10%10%9%15%
2340
July1st to 15thDay
5%6%39%9%6%9%8%9%12%18%
2340
16th to endDay
5%427%9%5%10%9%10%12%22%
2465
August1st to 15thDay
5%6%28%7%5%9%9%10%11%22%
2235
16th to endDay
8%5%28%8%5%8%9%9%12%18%
2190
September1st to 15thDay
8%6%38%10%6%9%8%9%11%15%
1980
16th to endDay
11%9%49%9%5%8%7%8%8%15%
1980
October1st to 15thDay
9%7%39%8%6%8%8%9%11%18%
1857
16th to endDay
13%8%27%6%35%6%7%9%28%
1920
November1st to 15thDay
8%6%36%6%46%7%7%8%34%
1907
16th to endDay
10%6%35%6%47%6%6%9%33%
1950
December1st to 15thDay
10%6%36%5%46%6%6%9%33%
1888
16th to endDay
6%5%246%35%6%9%11%35%
1872
January1st to 15thNight
7%5%25%6%46%6%7%10%36%
2522
16th to endNight
6%435%5%35%6%7%10%42%
2681
February1st to 15thNight
7%425%5%3445%9%47%
2255
16th to endNight
43144245%5%10%52%
1812
March1st to 15thNight
4325%5%35%6%6%8%47%
1980
16th to endNight
5%314435%6%6%10%48%
2112
April1st to 15thNight
322332446%10%55%
1973
16th to endNight
6%314435%6%7%10%46%
1800
May1st to 15thNight
32125%2447%10%55%
1799
16th to endNight
8%5%36%6%47%6%7%11%32%
1757
June1st to 15thNight
11%6%27%8%5%8%9%7%10%21%
1620
16th to endNight
44247%5%7%9%10%15%27%
1620
July1st to 15thNight
4447%7%38%7%9%12%29%
1620
16th to endNight
2425%5%36%6%8%12%40%
1703
August1st to 15thNight
4425%6%46%7%9%14%34%
1713
16th to endNight
6%5%26%8%47%8%9%12%28%
2008
September1st to 15thNight
7%5%36%7%5%8%8%10%12%24%
1980
16th to endNight
8%6%48%8%5%8%8%8%10%21%
1980
October1st to 15thNight
7%6%27%8%47%8%9%11%25%
2101
16th to endNight
12%8%37%6%445%5%8%32%
2304
November1st to 15thNight
7%6%246%46%5%6%9%39%
2281
16th to endNight
9%5%26%6%36%5%6%8%38%
2340
December1st to 15thNight
9%5%35%5%35%6%7%10%37%
2399
16th to endNight
6%424435%6%6%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
42%10%14%16%12%3
1747
16th to endDay
38%9%15%17%15%3
1892
February1st to 15thDay
36%7%13%22%16%4
1929
16th to endDay
29%9%14%25%16%4
1808
March1st to 15thDay
33%10%16%21%15%2
1980
16th to endDay
32%10%17%20%13%4
2112
April1st to 15thDay
27%10%21%24%14%1
1972
16th to endDay
32%10%17%20%16%3
2160
May1st to 15thDay
29%11%16%23%14%5%
2152
16th to endDay
46%14%16%18%4
2367
June1st to 15thDay
56%15%15%9%2
2340
16th to endDay
47%21%20%9%1
2340
July1st to 15thDay
45%22%23%8%
2201
16th to endDay
39%21%28%10%
2310
August1st to 15thDay
41%21%21%12%2
2222
16th to endDay
45%20%23%9%
2190
September1st to 15thDay
49%22%20%6%1
1980
16th to endDay
54%19%14%8%2
1980
October1st to 15thDay
49%15%14%13%5%
1857
16th to endDay
46%8%13%14%12%4
1920
November1st to 15thDay
41%8%13%16%15%3
1907
16th to endDay
40%9%14%12%19%4
1950
December1st to 15thDay
41%10%11%17%15%3
1888
16th to endDay
36%10%13%22%15%1
1872
January1st to 15thNight
40%9%15%20%10%2
2522
16th to endNight
37%8%13%21%14%3
2681
February1st to 15thNight
33%6%12%24%16%5%
2263
16th to endNight
26%7%14%24%20%5%
1812
March1st to 15thNight
33%7%12%24%18%4
1980
16th to endNight
30%9%15%24%17%3
2112
April1st to 15thNight
24%6%18%32%15%2
1973
16th to endNight
31%7%17%22%17%3
1800
May1st to 15thNight
23%7%16%33%14%4
1800
16th to endNight
44%9%17%22%6%
1759
June1st to 15thNight
51%15%18%11%3
1620
16th to endNight
39%16%30%12%
1620
July1st to 15thNight
43%16%28%11%
1530
16th to endNight
32%15%34%15%2
1595
August1st to 15thNight
34%18%28%17%2
1702
16th to endNight
43%15%27%13%
2008
September1st to 15thNight
46%18%23%9%1
1980
16th to endNight
53%16%17%8%3
1980
October1st to 15thNight
47%14%17%11%7%1
2101
16th to endNight
50%6%12%15%10%4
2304
November1st to 15thNight
43%7%10%18%17%3
2281
16th to endNight
45%7%9%16%15%5%
2340
December1st to 15thNight
43%8%12%17%15%3
2399
16th to endNight
32%8%12%26%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
17%6%36%27%11%
135
16th to endDay
12%13%28%34%9%1
144
February1st to 15thDay
6%5%21%44%22%
163
16th to endDay
9%12%16%37%21%1
265
March1st to 15thDay
7%14%25%37%13%1
270
16th to endDay
8%13%22%31%20%3
288
April1st to 15thDay
212%20%34%24%5%
270
16th to endDay
7%12%11%40%27%1
270
May1st to 15thDay
210%11%31%32%11%
288
16th to endDay
5%10%415%41%22%
331
June1st to 15thDay
10%10%419%27%26%
315
16th to endDay
5%9%28%30%43%
315
July1st to 15thDay
36%8%34%45%
305
16th to endDay
49%26%33%43%
326
August1st to 15thDay
8%6%8%34%41%
313
16th to endDay
11%4312%28%39%
332
September1st to 15thDay
10%5%411%25%44%
315
16th to endDay
14%5%29%26%40%
314
October1st to 15thDay
12%6%6%26%34%13%
315
16th to endDay
19%7%13%26%25%8%
336
November1st to 15thDay
8%8%11%33%30%8%
325
16th to endDay
15%11%19%31%18%2
330
December1st to 15thDay
14%8%15%34%22%3
268
16th to endDay
326%38%45%2
144
January1st to 15thNight
10%20%18%27%20%2
780
16th to endNight
7%20%20%35%15%
832
February1st to 15thNight
8%17%17%35%20%
764
16th to endNight
6%17%18%35%20%1
659
March1st to 15thNight
8%19%19%32%18%2
720
16th to endNight
6%18%16%35%21%1
768
April1st to 15thNight
317%10%40%26%1
718
16th to endNight
8%17%11%37%24%1
720
May1st to 15thNight
317%8%32%34%3
720
16th to endNight
7%18%419%39%11%
638
June1st to 15thNight
11%17%213%32%23%
540
16th to endNight
416%27%32%36%
540
July1st to 15thNight
5%11%1436%39%
510
16th to endNight
316%2426%46%
564
August1st to 15thNight
7%9%16%37%37%
632
16th to endNight
9%8%410%33%33%
764
September1st to 15thNight
10%8%39%30%37%
720
16th to endNight
12%8%49%33%31%
717
October1st to 15thNight
13%8%6%22%35%13%
720
16th to endNight
18%9%13%23%26%9%
768
November1st to 15thNight
11%15%13%29%23%6%
760
16th to endNight
12%17%14%28%23%3
780
December1st to 15thNight
11%17%14%28%25%2
780
16th to endNight
5%17%9%29%31%5%
832
Page generated at 2018-02-23 11:21:32. Version ac04

Copyright 2018 A. Danko


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