Fort Clinch State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Clinch State Park clear sky chart from 2005-11-05 to 2017-09-14.

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
51%
15874
20%
46881
14%
15836
58%
15836
25%
29624

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
34%
717
20%
2327
10%
716
47%
716
20%
1439
January16th to endNight
38%
768
22%
2496
14%
768
49%
768
23%
1521
February1st to 15thNight
38%
701
22%
2128
13%
700
49%
700
24%
1313
February16th to endNight
38%
631
24%
1841
13%
631
49%
631
25%
1136
March1st to 15thNight
45%
720
27%
1980
15%
720
56%
720
32%
1164
March16th to endNight
47%
768
24%
2112
13%
768
56%
768
32%
1245
April1st to 15thNight
50%
718
24%
1976
16%
718
58%
718
33%
1177
April16th to endNight
54%
711
28%
1794
16%
711
61%
711
37%
1048
May1st to 15thNight
60%
539
25%
1619
17%
539
65%
539
33%
915
May16th to endNight
59%
561
21%
1682
12%
561
65%
561
27%
1010
June1st to 15thNight
63%
540
15%
1620
12%
540
64%
540
25%
1042
June16th to endNight
62%
540
11%
1620
8%
540
64%
540
21%
1101
July1st to 15thNight
66%
510
11%
1530
9%
510
67%
510
24%
1002
July16th to endNight
68%
564
12%
1595
10%
531
73%
531
23%
1056
August1st to 15thNight
67%
539
11%
1609
10%
536
68%
536
21%
1091
August16th to endNight
60%
702
11%
1944
10%
702
61%
702
20%
1416
September1st to 15thNight
59%
716
11%
1969
9%
716
60%
716
19%
1464
September16th to endNight
48%
657
12%
1815
7%
657
53%
657
14%
1377
October1st to 15thNight
54%
660
25%
1900
24%
660
58%
660
26%
1202
October16th to endNight
58%
704
28%
2112
25%
704
66%
704
30%
1255
November1st to 15thNight
49%
700
26%
2101
22%
700
56%
700
28%
1264
November16th to endNight
43%
720
25%
2275
17%
720
55%
720
25%
1365
December1st to 15thNight
42%
720
22%
2340
16%
720
52%
720
22%
1445
December16th to endNight
47%
768
21%
2496
15%
768
55%
768
21%
1576

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
9%5%25%5%35%5%6%9%41%
47821
Night
9%5%25%5%345%6%8%43%
47086
TransparencyDay
36%9%16%19%13%5%
47522
Night
36%7%14%19%14%6%
46889
SeeingDay
10%9%9%21%29%19%
5726
Night
10%16%12%23%27%8%
15883

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%35%4245%48%42%
1611
16th to endDay
13%5%35%5%23447%45%
1728
February1st to 15thDay
14%6%35%423336%45%
1727
16th to endDay
12%5%25%324346%48%
1631
March1st to 15thDay
8%42331345%8%54%
1980
16th to endDay
8%425%43445%5%51%
2111
April1st to 15thDay
6%5%245%245%5%8%49%
1972
16th to endDay
6%31442436%8%53%
2173
May1st to 15thDay
6%313425%46%9%51%
2331
16th to endDay
8%3135%45%6%7%10%43%
2431
June1st to 15thDay
8%425%6%46%6%7%11%35%
2340
16th to endDay
7%426%7%47%7%8%11%32%
2340
July1st to 15thDay
6%425%6%46%7%10%13%32%
2340
16th to endDay
6%435%6%47%7%8%12%31%
2465
August1st to 15thDay
7%5%27%8%5%9%8%8%12%26%
2340
16th to endDay
11%5%36%7%46%8%8%10%28%
2242
September1st to 15thDay
10%6%27%6%47%7%8%9%28%
1967
16th to endDay
19%7%26%6%46%5%6%9%24%
1815
October1st to 15thDay
13%5%25%5%24447%42%
1729
16th to endDay
9%424434447%50%
1760
November1st to 15thDay
9%5%25%32445%7%50%
1757
16th to endDay
10%5%35%5%24336%48%
1683
December1st to 15thDay
14%5%35%435%35%7%42%
1620
16th to endDay
9%425%5%35%5%6%7%43%
1728
January1st to 15thNight
12%6%35%43445%6%43%
2327
16th to endNight
13%6%24434346%45%
2496
February1st to 15thNight
13%5%245%33335%48%
2124
16th to endNight
12%425%434345%47%
1841
March1st to 15thNight
7%425%42345%7%52%
1980
16th to endNight
8%424423347%55%
2112
April1st to 15thNight
8%423324448%53%
1976
16th to endNight
6%32332346%8%55%
1794
May1st to 15thNight
6%2133245%6%9%53%
1619
16th to endNight
6%4235%345%6%10%46%
1682
June1st to 15thNight
8%4245%36%5%9%12%37%
1620
16th to endNight
7%5%25%445%6%9%14%34%
1620
July1st to 15thNight
6%315%6%45%6%9%13%36%
1620
16th to endNight
3425%6%47%7%9%13%33%
1703
August1st to 15thNight
5%426%6%46%7%10%12%34%
1620
16th to endNight
10%5%36%6%35%8%9%11%29%
1944
September1st to 15thNight
11%6%36%7%5%6%7%6%9%28%
1969
16th to endNight
15%7%37%6%46%5%7%10%24%
1815
October1st to 15thNight
12%5%25%42335%7%44%
1900
16th to endNight
8%3245%345%46%51%
2112
November1st to 15thNight
9%42442435%7%49%
2101
16th to endNight
10%5%35%5%24446%48%
2275
December1st to 15thNight
12%6%35%424447%43%
2340
16th to endNight
10%6%25%5%3446%8%42%
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
40%5%9%19%16%8%
1612
16th to endDay
38%48%19%20%8%
1728
February1st to 15thDay
40%48%14%21%11%
1729
16th to endDay
36%49%18%19%11%
1631
March1st to 15thDay
27%412%25%21%7%
1980
16th to endDay
33%6%14%18%20%7%
2112
April1st to 15thDay
29%8%11%22%20%8%
1972
16th to endDay
26%5%15%25%21%6%
2173
May1st to 15thDay
27%6%14%27%18%4
2331
16th to endDay
31%10%16%24%14%3
2435
June1st to 15thDay
36%11%20%22%7%
2340
16th to endDay
37%14%23%18%6%
2340
July1st to 15thDay
32%13%32%18%2
2201
16th to endDay
36%13%27%18%4
2310
August1st to 15thDay
40%17%26%13%1
2327
16th to endDay
42%16%24%14%1
2242
September1st to 15thDay
43%13%19%14%8%
1967
16th to endDay
51%11%14%12%7%2
1815
October1st to 15thDay
38%6%9%19%17%7%
1729
16th to endDay
32%5%8%19%21%11%
1760
November1st to 15thDay
33%5%10%22%20%8%
1757
16th to endDay
35%5%9%20%18%10%
1683
December1st to 15thDay
41%5%12%21%14%4
1620
16th to endDay
37%7%13%21%12%7%
1728
January1st to 15thNight
38%6%10%19%17%7%
2327
16th to endNight
39%49%15%19%11%
2496
February1st to 15thNight
38%47%15%20%13%
2133
16th to endNight
37%410%17%18%10%
1841
March1st to 15thNight
30%413%24%18%8%
1980
16th to endNight
30%413%20%21%9%
2112
April1st to 15thNight
30%5%10%22%21%9%
1976
16th to endNight
26%5%14%23%22%6%
1794
May1st to 15thNight
26%8%15%25%19%5%
1620
16th to endNight
30%9%17%25%13%3
1684
June1st to 15thNight
35%10%21%24%7%
1620
16th to endNight
35%14%21%19%6%
1620
July1st to 15thNight
35%12%29%19%2
1530
16th to endNight
34%15%25%21%2
1595
August1st to 15thNight
35%16%29%15%3
1609
16th to endNight
41%15%23%15%3
1944
September1st to 15thNight
47%12%16%15%6%1
1969
16th to endNight
51%10%14%12%8%2
1815
October1st to 15thNight
37%6%10%18%18%7%
1900
16th to endNight
33%6%8%18%21%12%
2112
November1st to 15thNight
33%6%9%19%21%8%
2101
16th to endNight
36%49%18%18%11%
2275
December1st to 15thNight
39%413%20%15%5%
2340
16th to endNight
39%6%12%21%12%8%
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
15%5%24%32%14%7%
90
16th to endDay
14%6%28%33%17%
96
February1st to 15thDay
11%5%27%30%22%3
90
16th to endDay
12%8%23%44%10%
132
March1st to 15thDay
9%15%19%34%18%2
270
16th to endDay
9%14%18%32%19%5%
288
April1st to 15thDay
7%14%22%26%24%6%
270
16th to endDay
5%11%14%21%33%14%
270
May1st to 15thDay
5%11%11%35%26%10%
288
16th to endDay
7%10%414%35%27%
331
June1st to 15thDay
10%10%214%33%28%
315
16th to endDay
10%9%18%34%34%
315
July1st to 15thDay
36%2335%48%
305
16th to endDay
6%9%29%33%37%
326
August1st to 15thDay
9%6%110%34%38%
313
16th to endDay
12%5%18%35%37%
332
September1st to 15thDay
13%7%414%33%26%
310
16th to endDay
21%8%6%14%30%18%
254
October1st to 15thDay
19%8%7%29%27%8%
255
16th to endDay
7%7%13%28%35%7%
272
November1st to 15thDay
12%13%12%32%21%7%
265
16th to endDay
11%9%15%29%27%6%
153
December1st to 15thDay
4323%43%24%1
90
16th to endDay
16%14%32%34%2
96
January1st to 15thNight
13%24%21%26%11%2
720
16th to endNight
12%20%22%31%12%
768
February1st to 15thNight
13%21%21%29%12%1
704
16th to endNight
13%19%21%35%10%
631
March1st to 15thNight
9%19%17%35%17%
720
16th to endNight
10%18%17%32%19%2
768
April1st to 15thNight
9%18%17%26%26%2
718
16th to endNight
8%19%13%26%27%4
711
May1st to 15thNight
6%17%10%31%29%3
540
16th to endNight
9%17%5%16%36%13%
563
June1st to 15thNight
8%16%219%38%14%
540
16th to endNight
7%17%313%39%18%
540
July1st to 15thNight
7%12%311%43%22%
510
16th to endNight
416%19%46%22%
564
August1st to 15thNight
6%9%29%48%23%
539
16th to endNight
12%8%411%36%25%
702
September1st to 15thNight
14%9%212%45%15%
716
16th to endNight
20%9%417%36%11%
657
October1st to 15thNight
15%10%9%22%33%7%
660
16th to endNight
10%11%12%26%30%8%
704
November1st to 15thNight
10%18%15%31%21%3
700
16th to endNight
10%20%18%27%19%5%
720
December1st to 15thNight
10%21%18%22%22%3
720
16th to endNight
10%21%13%30%22%1
768
Page generated at 2017-09-15 10:29:57. Version ac04

Copyright 2017 A. Danko


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