Cedar Key
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cedar Key clear sky chart from 2005-11-05 to

2017-09-12
.

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%
15731
22%
46897
19%
15692
67%
15692
32%
28442

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
47%
717
20%
2327
15%
716
55%
716
27%
1406
January16th to endNight
47%
768
24%
2391
18%
768
56%
768
27%
1477
February1st to 15thNight
51%
701
26%
2105
19%
699
58%
699
34%
1241
February16th to endNight
50%
631
23%
1893
14%
631
58%
631
30%
1160
March1st to 15thNight
61%
720
29%
1986
20%
720
67%
720
42%
1142
March16th to endNight
63%
768
27%
2112
21%
768
67%
768
42%
1201
April1st to 15thNight
65%
718
24%
1976
18%
718
68%
718
39%
1160
April16th to endNight
69%
628
29%
1804
23%
628
73%
628
44%
975
May1st to 15thNight
76%
539
27%
1619
23%
539
79%
539
44%
852
May16th to endNight
79%
561
26%
1682
23%
561
79%
561
41%
934
June1st to 15thNight
69%
540
15%
1620
15%
540
69%
540
28%
1038
June16th to endNight
76%
540
11%
1620
10%
540
76%
540
30%
1028
July1st to 15thNight
70%
510
9%
1530
9%
510
70%
510
23%
1032
July16th to endNight
73%
564
7%
1595
8%
531
74%
531
22%
1111
August1st to 15thNight
72%
539
6%
1687
7%
536
72%
536
24%
1122
August16th to endNight
69%
651
11%
1988
13%
651
69%
651
22%
1360
September1st to 15thNight
64%
707
9%
1944
9%
707
64%
707
22%
1401
September16th to endNight
66%
657
17%
1815
15%
657
66%
657
24%
1262
October1st to 15thNight
71%
660
28%
1829
27%
660
74%
660
39%
1069
October16th to endNight
66%
704
30%
2112
30%
704
70%
704
37%
1194
November1st to 15thNight
69%
700
33%
2101
32%
700
73%
700
42%
1124
November16th to endNight
60%
720
28%
2325
25%
720
67%
720
35%
1282
December1st to 15thNight
54%
720
27%
2340
25%
720
60%
720
31%
1375
December16th to endNight
56%
768
24%
2496
24%
768
60%
768
29%
1496

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%424435%5%6%9%44%
47747
Night
8%425%5%345%6%9%45%
47104
TransparencyDay
33%6%17%20%15%6%
47448
Night
34%5%15%20%16%6%
46907
SeeingDay
9%17%20%34%25%
5607
Night
10%211%29%32%12%
15740

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
12%6%2442436%7%44%
1611
16th to endDay
10%5%3432446%7%47%
1830
February1st to 15thDay
16%5%34423335%47%
1750
16th to endDay
10%5%2432446%6%50%
1580
March1st to 15thDay
8%41331345%9%55%
1974
16th to endDay
8%5%13324447%54%
2111
April1st to 15thDay
5%3143245%6%9%52%
1972
16th to endDay
6%21322335%8%59%
2164
May1st to 15thDay
431342336%7%57%
2331
16th to endDay
5%213425%6%6%10%51%
2431
June1st to 15thDay
9%5%25%5%35%7%8%11%36%
2340
16th to endDay
6%4245%35%8%9%12%36%
2340
July1st to 15thDay
7%325%5%47%9%11%15%27%
2340
16th to endDay
7%5%26%7%5%8%9%9%13%23%
2465
August1st to 15thDay
11%5%25%5%47%9%10%14%24%
2258
16th to endDay
9%5%26%6%38%6%9%11%28%
2202
September1st to 15thDay
10%5%25%6%46%7%8%12%30%
1936
16th to endDay
10%6%36%6%36%6%6%11%34%
1815
October1st to 15thDay
6%5%25%42445%7%51%
1800
16th to endDay
6%423333346%56%
1760
November1st to 15thDay
6%32331335%9%57%
1757
16th to endDay
8%424424438%52%
1632
December1st to 15thDay
10%5%34434448%47%
1620
16th to endDay
9%5%345%25%5%6%7%44%
1728
January1st to 15thNight
11%6%25%43445%10%41%
2327
16th to endNight
14%5%34425%45%6%43%
2391
February1st to 15thNight
11%5%24424345%50%
2103
16th to endNight
9%8%25%424446%47%
1893
March1st to 15thNight
6%5%134245%47%53%
1986
16th to endNight
8%42442335%5%56%
2112
April1st to 15thNight
6%5%234345%5%9%50%
1976
16th to endNight
5%31431345%8%56%
1804
May1st to 15thNight
5%21232346%10%57%
1619
16th to endNight
5%31332447%8%53%
1682
June1st to 15thNight
10%5%25%5%345%6%10%40%
1620
16th to endNight
6%4246%36%6%7%14%38%
1620
July1st to 15thNight
6%426%7%46%7%9%14%32%
1620
16th to endNight
3435%7%49%8%10%13%27%
1703
August1st to 15thNight
7%326%6%46%9%9%13%30%
1698
16th to endNight
9%426%7%45%6%8%12%32%
1988
September1st to 15thNight
10%5%37%7%47%6%8%11%27%
1944
16th to endNight
11%5%36%6%36%6%6%11%31%
1815
October1st to 15thNight
5%42443345%9%50%
1829
16th to endNight
6%425%42445%7%52%
2112
November1st to 15thNight
6%31342345%6%57%
2101
16th to endNight
8%325%42445%7%51%
2325
December1st to 15thNight
11%6%35%423348%46%
2340
16th to endNight
9%6%26%5%2446%8%44%
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
38%29%21%20%7%
1612
16th to endDay
35%39%19%22%10%
1830
February1st to 15thDay
40%26%14%20%15%
1752
16th to endDay
32%411%15%24%11%
1580
March1st to 15thDay
27%212%24%24%8%
1974
16th to endDay
29%311%25%21%9%
2112
April1st to 15thDay
26%5%12%23%24%7%
1972
16th to endDay
22%412%27%25%8%
2164
May1st to 15thDay
24%415%25%22%7%
2331
16th to endDay
26%6%18%28%17%3
2435
June1st to 15thDay
37%8%23%25%5%
2340
16th to endDay
35%10%25%22%6%
2340
July1st to 15thDay
38%13%33%14%1
2201
16th to endDay
44%10%29%13%2
2310
August1st to 15thDay
41%12%30%13%1
2245
16th to endDay
42%10%27%17%1
2202
September1st to 15thDay
40%11%27%14%5%
1936
16th to endDay
42%7%16%21%8%3
1815
October1st to 15thDay
30%412%19%20%12%
1800
16th to endDay
28%38%18%27%13%
1760
November1st to 15thDay
24%211%26%23%11%
1757
16th to endDay
32%29%20%22%12%
1632
December1st to 15thDay
35%211%24%18%6%
1620
16th to endDay
35%411%25%14%8%
1728
January1st to 15thNight
39%311%19%19%6%
2327
16th to endNight
40%38%14%24%9%
2391
February1st to 15thNight
34%27%17%22%15%
2112
16th to endNight
37%49%14%24%9%
1893
March1st to 15thNight
29%212%24%21%9%
1986
16th to endNight
29%211%25%19%11%
2112
April1st to 15thNight
30%413%21%23%6%
1976
16th to endNight
25%411%29%22%6%
1804
May1st to 15thNight
23%5%14%27%20%8%
1620
16th to endNight
27%5%17%27%20%2
1684
June1st to 15thNight
38%7%22%26%5%
1620
16th to endNight
33%10%26%23%5%
1620
July1st to 15thNight
40%11%30%15%2
1530
16th to endNight
39%14%30%11%3
1595
August1st to 15thNight
38%11%35%13%1
1687
16th to endNight
40%12%26%16%3
1988
September1st to 15thNight
45%10%25%14%3
1944
16th to endNight
45%7%18%18%8%2
1815
October1st to 15thNight
30%413%19%20%11%
1829
16th to endNight
31%37%17%27%12%
2112
November1st to 15thNight
27%27%26%24%10%
2101
16th to endNight
32%39%22%17%15%
2325
December1st to 15thNight
37%29%28%15%5%
2340
16th to endNight
38%310%24%15%7%
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
16%315%33%21%10%
90
16th to endDay
9%10%21%34%21%2
96
February1st to 15thDay
11%324%25%26%8%
90
16th to endDay
425%40%24%3
81
March1st to 15thDay
9%317%39%25%4
264
16th to endDay
9%19%36%29%3
288
April1st to 15thDay
6%316%36%29%7%
270
16th to endDay
5%11%36%37%9%
270
May1st to 15thDay
8%18%32%35%13%
288
16th to endDay
6%411%46%30%
331
June1st to 15thDay
16%1113%37%30%
315
16th to endDay
8%1435%50%
315
July1st to 15thDay
6%1332%55%
305
16th to endDay
8%25%34%46%
326
August1st to 15thDay
16%5%30%44%
313
16th to endDay
10%11337%45%
332
September1st to 15thDay
20%19%31%37%
299
16th to endDay
14%111%46%25%
254
October1st to 15thDay
8%428%40%17%
255
16th to endDay
7%111%30%37%12%
272
November1st to 15thDay
6%210%33%34%12%
265
16th to endDay
5%5%33%42%12%
102
December1st to 15thDay
10%213%38%28%6%
90
16th to endDay
7%112%27%37%14%
96
January1st to 15thNight
14%422%32%23%2
720
16th to endNight
17%5%19%35%20%1
768
February1st to 15thNight
13%323%38%19%1
704
16th to endNight
11%323%42%17%
631
March1st to 15thNight
8%219%42%23%3
720
16th to endNight
10%116%39%27%3
768
April1st to 15thNight
8%213%40%30%3
718
16th to endNight
7%114%35%36%4
628
May1st to 15thNight
7%17%41%33%8%
540
16th to endNight
6%1425%47%14%
563
June1st to 15thNight
13%1215%46%19%
540
16th to endNight
9%9%45%34%
540
July1st to 15thNight
8%19%35%44%
510
16th to endNight
6%16%39%46%
564
August1st to 15thNight
8%2442%41%
539
16th to endNight
10%2111%40%33%
651
September1st to 15thNight
11%1113%41%29%
707
16th to endNight
14%1124%45%13%
657
October1st to 15thNight
7%17%34%41%7%
660
16th to endNight
9%111%36%35%6%
704
November1st to 15thNight
7%39%44%29%6%
700
16th to endNight
9%218%40%25%3
720
December1st to 15thNight
14%218%32%28%4
720
16th to endNight
13%216%35%27%3
768
Page generated at 2017-09-13 07:39:23. Version ac04

Copyright 2017 A. Danko


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