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 2018-03-21.

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%
16492
22%
49195
19%
16453
67%
16453
32%
29727

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
45%
777
21%
2522
15%
776
55%
776
26%
1527
January16th to endNight
47%
832
26%
2590
20%
832
56%
832
27%
1585
February1st to 15thNight
52%
761
25%
2285
18%
759
58%
759
33%
1368
February16th to endNight
51%
683
25%
2049
16%
683
59%
683
30%
1249
March1st to 15thNight
60%
780
29%
2152
19%
780
67%
780
42%
1227
March16th to endNight
63%
792
28%
2178
21%
792
67%
792
42%
1237
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
65%
720
10%
1980
9%
720
65%
720
22%
1423
September16th to endNight
67%
717
19%
1980
18%
717
68%
717
26%
1352
October1st to 15thNight
71%
720
27%
1995
26%
720
73%
720
38%
1173
October16th to endNight
66%
768
32%
2304
31%
768
71%
768
38%
1295
November1st to 15thNight
71%
760
32%
2281
32%
760
75%
760
44%
1202
November16th to endNight
61%
780
30%
2519
27%
780
68%
780
36%
1376
December1st to 15thNight
54%
780
27%
2535
24%
780
61%
780
31%
1482
December16th to endNight
57%
832
24%
2704
24%
832
61%
832
29%
1619

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%
49638
Night
8%425%5%345%6%9%45%
49402
TransparencyDay
33%6%17%21%15%6%
49339
Night
34%5%15%21%16%6%
49205
SeeingDay
9%17%21%34%23%
6265
Night
10%211%30%32%12%
16501

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%25%43436%6%44%
1746
16th to endDay
10%5%2432445%7%48%
1983
February1st to 15thDay
15%5%34424345%46%
1900
16th to endDay
9%5%2432445%6%51%
1710
March1st to 15thDay
7%313313448%56%
2138
16th to endDay
7%5%14324447%55%
2173
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%31%
1980
16th to endDay
10%6%26%6%35%5%6%10%36%
1980
October1st to 15thDay
6%5%24425%45%7%51%
1963
16th to endDay
6%423333346%56%
1920
November1st to 15thDay
5%32231345%9%58%
1907
16th to endDay
8%424324338%53%
1768
December1st to 15thDay
9%5%34423448%47%
1755
16th to endDay
8%5%345%25%5%6%7%44%
1872
January1st to 15thNight
12%6%25%43445%9%41%
2522
16th to endNight
14%5%3442445%6%44%
2590
February1st to 15thNight
11%5%2442445%6%48%
2283
16th to endNight
9%8%25%424435%48%
2049
March1st to 15thNight
6%5%13423447%54%
2152
16th to endNight
8%424423345%56%
2178
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%36%6%47%6%8%11%27%
1980
16th to endNight
10%5%25%6%36%6%6%11%33%
1980
October1st to 15thNight
5%42443446%9%50%
1995
16th to endNight
6%425%42345%7%53%
2304
November1st to 15thNight
5%21342345%6%58%
2281
16th to endNight
7%325%42435%7%52%
2519
December1st to 15thNight
11%6%35%423348%47%
2535
16th to endNight
8%6%25%5%3446%8%43%
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
39%29%20%20%6%
1747
16th to endDay
34%38%19%23%10%
1983
February1st to 15thDay
40%28%14%19%14%
1902
16th to endDay
31%411%16%25%11%
1710
March1st to 15thDay
26%312%23%24%9%
2138
16th to endDay
29%312%25%21%9%
2174
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
39%11%27%14%5%
1980
16th to endDay
41%7%16%22%9%3
1980
October1st to 15thDay
30%5%13%19%20%11%
1963
16th to endDay
27%38%17%27%14%
1920
November1st to 15thDay
23%211%27%24%10%
1907
16th to endDay
31%29%21%24%11%
1768
December1st to 15thDay
34%312%24%17%7%
1755
16th to endDay
35%411%25%14%7%
1872
January1st to 15thNight
39%310%19%20%6%
2522
16th to endNight
39%37%14%24%9%
2590
February1st to 15thNight
35%38%17%21%14%
2292
16th to endNight
37%49%14%25%8%
2049
March1st to 15thNight
29%211%23%21%10%
2152
16th to endNight
29%211%25%19%11%
2178
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%24%15%3
1980
16th to endNight
42%7%17%20%8%2
1980
October1st to 15thNight
31%413%19%20%10%
1995
16th to endNight
30%36%17%27%13%
2304
November1st to 15thNight
26%37%27%25%9%
2281
16th to endNight
31%38%22%19%14%
2519
December1st to 15thNight
36%29%28%15%6%
2535
16th to endNight
38%310%24%15%7%
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%317%35%18%6%
135
16th to endDay
9%7%20%38%21%2
144
February1st to 15thDay
11%217%31%26%9%
135
16th to endDay
319%35%35%5%
120
March1st to 15thDay
8%421%38%23%3
323
16th to endDay
9%118%37%28%3
311
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
19%119%33%35%
315
16th to endDay
13%10%46%28%
314
October1st to 15thDay
7%6%28%38%18%
315
16th to endDay
7%212%30%36%11%
336
November1st to 15thDay
5%18%31%38%14%
325
16th to endDay
6%6%29%41%15%
148
December1st to 15thDay
8%311%40%28%5%
135
16th to endDay
6%211%29%37%11%
144
January1st to 15thNight
14%423%32%22%2
780
16th to endNight
17%5%19%36%20%1
832
February1st to 15thNight
13%322%38%19%2
764
16th to endNight
10%321%41%20%1
683
March1st to 15thNight
7%321%42%22%3
780
16th to endNight
10%117%39%28%3
792
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%
720
16th to endNight
12%123%46%14%
717
October1st to 15thNight
7%18%34%40%7%
720
16th to endNight
9%111%37%33%5%
768
November1st to 15thNight
6%39%43%30%6%
760
16th to endNight
9%217%40%26%3
780
December1st to 15thNight
13%218%32%28%4
780
16th to endNight
12%216%36%28%3
832
Page generated at 2018-03-22 11:34:27. Version ac04

Copyright 2018 A. Danko


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