St. Sebastian River Preserve State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the St. Sebastian River Preserve State Park clear sky chart from 2005-11-05 to 2017-12-20.

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%
16508
18%
48042
15%
16468
66%
16468
28%
31252

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
49%
717
18%
2327
15%
716
56%
716
25%
1474
January16th to endNight
47%
768
23%
2496
18%
768
57%
768
28%
1519
February1st to 15thNight
50%
701
24%
2109
18%
698
59%
698
34%
1254
February16th to endNight
57%
631
27%
1761
17%
631
66%
631
39%
1027
March1st to 15thNight
57%
720
28%
1980
19%
720
65%
720
39%
1150
March16th to endNight
61%
768
23%
2112
18%
768
65%
768
39%
1249
April1st to 15thNight
67%
718
22%
1970
19%
718
70%
718
42%
1121
April16th to endNight
65%
720
25%
1800
16%
720
69%
720
40%
1120
May1st to 15thNight
75%
687
24%
1767
16%
687
76%
687
42%
1067
May16th to endNight
74%
561
18%
1682
14%
561
75%
561
28%
1080
June1st to 15thNight
68%
540
10%
1620
9%
540
68%
540
20%
1165
June16th to endNight
75%
540
10%
1620
8%
540
75%
540
22%
1154
July1st to 15thNight
69%
510
7%
1530
6%
510
69%
510
19%
1111
July16th to endNight
77%
564
8%
1595
8%
531
78%
531
22%
1119
August1st to 15thNight
77%
566
8%
1636
8%
563
77%
563
25%
1124
August16th to endNight
68%
764
6%
1992
5%
764
68%
764
20%
1490
September1st to 15thNight
67%
720
6%
1980
6%
720
67%
720
17%
1518
September16th to endNight
59%
717
9%
1980
9%
717
59%
717
15%
1556
October1st to 15thNight
64%
720
19%
2095
21%
720
65%
720
24%
1409
October16th to endNight
60%
768
22%
2304
20%
768
64%
768
26%
1472
November1st to 15thNight
63%
760
22%
2281
20%
760
67%
760
28%
1467
November16th to endNight
55%
780
25%
2340
21%
780
61%
780
27%
1498
December1st to 15thNight
55%
780
22%
2506
20%
780
60%
780
24%
1599
December16th to endNight
61%
788
23%
2559
22%
788
66%
788
30%
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%5%36%7%47%7%7%9%32%
48777
Night
7%5%25%5%35%5%7%10%40%
48251
TransparencyDay
41%10%16%16%11%3
48478
Night
36%9%16%19%12%4
48054
SeeingDay
9%111%22%28%25%
6314
Night
9%213%28%32%12%
16517

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
11%6%37%5%46%7%7%8%32%
1611
16th to endDay
9%5%25%5%35%5%6%8%42%
1728
February1st to 15thDay
9%5%26%5%3435%8%43%
1741
16th to endDay
8%5%25%4345%5%7%45%
1710
March1st to 15thDay
5%426%6%446%6%8%44%
1980
16th to endDay
8%425%6%35%6%5%8%42%
2111
April1st to 15thDay
5%325%6%46%6%7%9%42%
1978
16th to endDay
7%425%5%36%7%7%9%38%
2160
May1st to 15thDay
6%3145%46%7%6%10%43%
2192
16th to endDay
8%437%8%5%7%6%8%9%29%
2431
June1st to 15thDay
10%6%48%8%5%7%7%8%11%20%
2340
16th to endDay
8%6%47%7%6%9%7%8%11%23%
2340
July1st to 15thDay
9%6%37%7%49%10%9%11%21%
2340
16th to endDay
8%5%38%9%5%9%8%9%10%20%
2465
August1st to 15thDay
5%437%9%5%8%8%10%12%23%
2300
16th to endDay
10%6%38%8%6%8%8%9%9%19%
2205
September1st to 15thDay
7%349%8%6%8%10%9%10%21%
1980
16th to endDay
10%7%38%9%7%8%8%7%9%18%
1980
October1st to 15thDay
9%5%37%7%5%7%7%8%10%27%
1863
16th to endDay
10%6%35%6%35%5%5%9%37%
1920
November1st to 15thDay
6%5%26%7%48%6%6%6%38%
1907
16th to endDay
8%6%37%7%46%5%6%8%36%
1950
December1st to 15thDay
10%6%36%5%46%6%6%7%35%
1781
16th to endDay
7%5%25%6%46%5%7%8%39%
1764
January1st to 15thNight
10%5%36%5%25%5%6%9%39%
2327
16th to endNight
9%5%25%435%46%8%43%
2496
February1st to 15thNight
11%5%24323446%50%
2109
16th to endNight
7%313325%46%8%51%
1761
March1st to 15thNight
431443445%9%53%
1980
16th to endNight
6%3244345%6%9%50%
2112
April1st to 15thNight
4213335%45%8%55%
1970
16th to endNight
6%324435%46%9%49%
1800
May1st to 15thNight
5%31333445%8%54%
1767
16th to endNight
5%425%436%7%9%13%37%
1682
June1st to 15thNight
9%7%35%7%47%7%9%12%25%
1620
16th to endNight
6%426%6%37%7%9%11%32%
1620
July1st to 15thNight
8%6%36%5%36%8%9%11%31%
1620
16th to endNight
4436%6%36%7%8%12%35%
1703
August1st to 15thNight
3425%5%47%8%9%14%33%
1647
16th to endNight
9%5%26%6%46%8%8%10%29%
1992
September1st to 15thNight
6%6%37%7%48%7%9%13%25%
1980
16th to endNight
9%8%39%8%5%6%7%7%10%23%
1980
October1st to 15thNight
7%6%36%6%45%6%7%8%37%
2095
16th to endNight
11%6%245%345%6%9%39%
2304
November1st to 15thNight
6%335%5%46%6%6%8%41%
2281
16th to endNight
8%5%35%5%35%5%6%9%39%
2340
December1st to 15thNight
8%5%36%6%35%5%6%8%39%
2506
16th to endNight
5%425%5%36%5%6%9%43%
2559

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
43%9%10%18%14%4
1612
16th to endDay
36%6%8%21%19%8%
1728
February1st to 15thDay
36%49%18%20%10%
1743
16th to endDay
34%6%13%19%19%6%
1710
March1st to 15thDay
33%6%12%25%17%4
1980
16th to endDay
34%8%14%19%17%5%
2112
April1st to 15thDay
30%9%16%20%18%3
1978
16th to endDay
35%7%13%18%20%4
2160
May1st to 15thDay
31%8%14%22%17%6%
2192
16th to endDay
42%10%16%18%11%
2435
June1st to 15thDay
50%11%18%16%2
2340
16th to endDay
46%13%23%12%3
2340
July1st to 15thDay
45%17%24%11%
2201
16th to endDay
46%14%24%12%
2310
August1st to 15thDay
40%17%30%11%
2287
16th to endDay
49%16%24%8%
2205
September1st to 15thDay
46%17%22%10%2
1980
16th to endDay
53%14%17%10%3
1980
October1st to 15thDay
44%11%13%15%12%3
1863
16th to endDay
41%5%11%13%21%6%
1920
November1st to 15thDay
39%6%11%21%16%5%
1907
16th to endDay
41%7%9%17%14%9%
1950
December1st to 15thDay
45%5%11%19%12%5%
1781
16th to endDay
36%8%15%20%14%4
1764
January1st to 15thNight
39%6%13%21%13%5%
2327
16th to endNight
37%5%10%23%15%8%
2496
February1st to 15thNight
33%49%20%21%10%
2118
16th to endNight
28%6%15%23%19%6%
1761
March1st to 15thNight
28%5%10%29%19%5%
1980
16th to endNight
28%7%14%22%19%7%
2112
April1st to 15thNight
25%7%17%25%18%5%
1970
16th to endNight
29%7%14%21%22%4
1800
May1st to 15thNight
26%7%12%27%17%6%
1768
16th to endNight
32%13%18%23%12%
1684
June1st to 15thNight
46%10%21%16%4
1620
16th to endNight
40%14%24%17%3
1620
July1st to 15thNight
41%16%25%14%1
1530
16th to endNight
34%19%29%15%1
1595
August1st to 15thNight
34%16%34%14%
1636
16th to endNight
43%16%27%12%
1992
September1st to 15thNight
45%18%21%12%2
1980
16th to endNight
51%14%16%12%31
1980
October1st to 15thNight
41%9%14%15%16%3
2095
16th to endNight
38%8%10%15%20%7%
2304
November1st to 15thNight
38%7%10%20%17%5%
2281
16th to endNight
39%6%11%18%16%7%
2340
December1st to 15thNight
41%6%12%21%11%6%
2506
16th to endNight
33%7%16%23%14%5%
2559

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
21%5%30%23%14%5%
90
16th to endDay
15%12%30%19%18%3
96
February1st to 15thDay
7%428%32%21%5%
90
16th to endDay
12%427%36%18%
211
March1st to 15thDay
5%426%38%20%5%
270
16th to endDay
7%422%30%26%8%
288
April1st to 15thDay
4123%33%28%8%
270
16th to endDay
8%112%32%28%16%
270
May1st to 15thDay
5%19%30%35%17%
288
16th to endDay
7%15%19%35%29%
331
June1st to 15thDay
13%1319%24%38%
315
16th to endDay
6%28%30%51%
315
July1st to 15thDay
6%432%54%
305
16th to endDay
10%9%27%51%
326
August1st to 15thDay
6%6%29%55%
313
16th to endDay
12%37%24%50%
332
September1st to 15thDay
9%412%26%46%
315
16th to endDay
11%215%32%36%
314
October1st to 15thDay
14%16%23%35%17%
315
16th to endDay
12%218%30%26%8%
336
November1st to 15thDay
7%212%34%31%10%
325
16th to endDay
9%217%39%27%3
330
December1st to 15thDay
10%319%38%22%4
161
16th to endDay
10%212%27%36%10%
108
January1st to 15thNight
12%6%20%32%23%3
720
16th to endNight
11%426%38%17%
768
February1st to 15thNight
12%424%39%17%1
704
16th to endNight
9%224%44%19%
631
March1st to 15thNight
6%326%42%18%2
720
16th to endNight
7%220%38%27%2
768
April1st to 15thNight
5%318%41%28%2
718
16th to endNight
7%114%44%27%4
720
May1st to 15thNight
7%18%44%32%5%
688
16th to endNight
7%5%25%43%16%
563
June1st to 15thNight
11%1416%48%18%
540
16th to endNight
7%210%46%32%
540
July1st to 15thNight
10%118%40%37%
510
16th to endNight
7%1446%39%
564
August1st to 15thNight
5%16%47%39%
566
16th to endNight
12%310%41%32%
764
September1st to 15thNight
9%1310%44%30%
720
16th to endNight
13%1215%42%24%
717
October1st to 15thNight
12%15%30%38%11%
720
16th to endNight
15%113%28%33%7%
768
November1st to 15thNight
8%216%33%33%6%
760
16th to endNight
11%319%35%26%3
780
December1st to 15thNight
12%317%37%25%3
780
16th to endNight
7%417%33%32%3
788
Page generated at 2017-12-21 07:04:43. Version ac04

Copyright 2017 A. Danko


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