Deltona
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Deltona clear sky chart from 2005-11-05 to 2017-09-17.

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
59%
15990
20%
46925
16%
15950
64%
15950
29%
29648

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%
719
20%
2327
14%
716
53%
716
24%
1444
January16th to endNight
42%
768
24%
2487
17%
768
53%
768
27%
1509
February1st to 15thNight
42%
701
24%
2105
15%
700
52%
700
32%
1251
February16th to endNight
43%
631
25%
1812
13%
631
54%
631
32%
1093
March1st to 15thNight
53%
720
29%
1980
17%
720
63%
720
43%
1107
March16th to endNight
53%
768
25%
2112
18%
768
58%
768
40%
1223
April1st to 15thNight
54%
718
24%
1976
16%
718
59%
718
39%
1147
April16th to endNight
59%
720
27%
1814
17%
720
63%
720
42%
1093
May1st to 15thNight
69%
596
26%
1676
19%
596
72%
596
42%
932
May16th to endNight
72%
561
21%
1682
18%
561
73%
561
32%
1039
June1st to 15thNight
69%
540
13%
1620
12%
540
69%
540
24%
1107
June16th to endNight
71%
540
8%
1620
7%
540
71%
540
22%
1160
July1st to 15thNight
70%
510
8%
1530
6%
510
70%
510
21%
1099
July16th to endNight
75%
564
9%
1595
9%
531
77%
531
22%
1111
August1st to 15thNight
79%
539
8%
1609
7%
536
79%
536
26%
1091
August16th to endNight
65%
738
10%
2004
9%
738
65%
738
22%
1435
September1st to 15thNight
67%
720
9%
1980
8%
720
67%
720
19%
1458
September16th to endNight
60%
665
12%
1837
11%
665
61%
665
18%
1389
October1st to 15thNight
68%
660
26%
1899
27%
660
70%
660
31%
1188
October16th to endNight
63%
704
27%
2112
27%
704
67%
704
33%
1268
November1st to 15thNight
59%
700
27%
2101
22%
700
67%
700
33%
1254
November16th to endNight
53%
720
28%
2211
21%
720
63%
720
32%
1306
December1st to 15thNight
52%
720
26%
2340
23%
720
59%
720
28%
1422
December16th to endNight
51%
768
22%
2496
20%
768
58%
768
27%
1522

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%37%7%46%6%6%8%35%
47834
Night
8%425%5%35%5%6%9%43%
47132
TransparencyDay
43%8%13%16%12%5%
47535
Night
35%8%15%20%13%6%
46935
SeeingDay
9%315%21%24%25%
5828
Night
9%318%31%29%7%
15997

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
10%6%46%5%35%6%5%8%38%
1611
16th to endDay
11%5%25%42445%7%45%
1734
February1st to 15thDay
10%5%35%5%34446%44%
1750
16th to endDay
9%425%7%3445%7%44%
1660
March1st to 15thDay
5%325%6%345%48%48%
1980
16th to endDay
8%425%6%346%47%45%
2111
April1st to 15thDay
7%3245%45%5%6%9%45%
1972
16th to endDay
5%425%5%46%6%6%8%43%
2145
May1st to 15thDay
6%315%5%35%5%6%7%46%
2283
16th to endDay
8%426%6%47%6%8%9%34%
2431
June1st to 15thDay
9%6%37%8%6%8%7%7%8%25%
2340
16th to endDay
9%6%48%9%5%8%8%7%8%24%
2340
July1st to 15thDay
9%7%38%9%6%9%8%8%8%21%
2340
16th to endDay
8%6%48%10%6%9%7%7%7%22%
2465
August1st to 15thDay
5%5%310%10%6%8%7%8%12%21%
2340
16th to endDay
11%6%49%9%6%8%6%7%9%21%
2182
September1st to 15thDay
9%6%38%10%5%7%8%7%9%22%
1980
16th to endDay
11%8%310%10%6%7%6%7%9%18%
1829
October1st to 15thDay
9%5%37%6%36%6%7%8%35%
1730
16th to endDay
10%5%25%5%35%5%5%7%43%
1760
November1st to 15thDay
6%425%5%46%5%6%8%44%
1757
16th to endDay
9%7%36%5%35%5%47%42%
1746
December1st to 15thDay
10%6%36%5%4446%7%39%
1620
16th to endDay
7%5%25%5%35%6%5%8%42%
1728
January1st to 15thNight
11%6%35%4345%5%9%41%
2327
16th to endNight
12%5%3442345%7%44%
2487
February1st to 15thNight
11%42442345%6%50%
2103
16th to endNight
7%325%5%25%5%47%49%
1812
March1st to 15thNight
5%32332445%8%56%
1980
16th to endNight
6%32442335%6%56%
2112
April1st to 15thNight
6%31433446%8%53%
1976
16th to endNight
6%31442345%9%52%
1814
May1st to 15thNight
5%2144245%5%8%56%
1676
16th to endNight
6%325%5%345%7%10%44%
1682
June1st to 15thNight
7%5%27%5%37%5%8%11%34%
1620
16th to endNight
6%5%37%7%45%7%8%10%32%
1620
July1st to 15thNight
7%426%7%36%7%9%11%31%
1620
16th to endNight
5%5%36%7%47%7%8%11%33%
1703
August1st to 15thNight
3327%7%46%7%10%12%34%
1620
16th to endNight
10%436%6%35%6%7%12%31%
2004
September1st to 15thNight
8%6%25%6%47%7%8%11%30%
1980
16th to endNight
10%8%27%7%49%7%8%9%24%
1837
October1st to 15thNight
7%425%4346%7%9%43%
1899
16th to endNight
9%5%25%5%23449%47%
2112
November1st to 15thNight
5%426%5%35%46%8%46%
2101
16th to endNight
8%424325%46%9%47%
2211
December1st to 15thNight
10%425%5%35%45%7%44%
2340
16th to endNight
8%5%25%5%35%5%5%9%43%
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
42%5%10%17%16%8%
1612
16th to endDay
37%5%9%16%20%10%
1734
February1st to 15thDay
40%47%12%20%13%
1752
16th to endDay
38%5%9%16%19%10%
1660
March1st to 15thDay
33%5%10%24%17%8%
1980
16th to endDay
36%5%12%18%19%8%
2112
April1st to 15thDay
33%7%11%19%21%6%
1972
16th to endDay
34%7%10%22%17%8%
2145
May1st to 15thDay
33%7%12%21%18%7%
2283
16th to endDay
41%8%15%18%12%3
2435
June1st to 15thDay
50%9%17%18%4
2340
16th to endDay
51%12%20%13%3
2340
July1st to 15thDay
53%14%19%12%1
2201
16th to endDay
53%13%18%12%1
2310
August1st to 15thDay
50%15%23%9%1
2327
16th to endDay
54%13%19%11%1
2182
September1st to 15thDay
52%14%17%11%3
1980
16th to endDay
57%10%14%11%42
1829
October1st to 15thDay
43%8%10%14%15%7%
1730
16th to endDay
38%6%7%15%21%10%
1760
November1st to 15thDay
35%5%10%19%21%7%
1757
16th to endDay
41%48%17%17%10%
1746
December1st to 15thDay
42%6%11%19%15%5%
1620
16th to endDay
37%6%14%19%13%8%
1728
January1st to 15thNight
39%5%10%20%15%7%
2327
16th to endNight
38%49%17%20%9%
2487
February1st to 15thNight
33%5%9%17%18%15%
2112
16th to endNight
33%6%13%17%21%8%
1812
March1st to 15thNight
25%414%28%19%6%
1980
16th to endNight
27%6%13%22%19%10%
2112
April1st to 15thNight
26%7%13%25%18%8%
1976
16th to endNight
28%5%12%26%19%7%
1814
May1st to 15thNight
25%6%16%26%17%7%
1677
16th to endNight
32%9%15%24%15%1
1684
June1st to 15thNight
40%10%20%23%3
1620
16th to endNight
41%13%22%16%4
1620
July1st to 15thNight
40%15%26%13%2
1530
16th to endNight
38%15%27%16%2
1595
August1st to 15thNight
34%15%36%12%1
1609
16th to endNight
42%12%27%15%1
2004
September1st to 15thNight
41%17%20%15%5%
1980
16th to endNight
49%12%17%15%41
1837
October1st to 15thNight
33%9%11%19%17%7%
1899
16th to endNight
34%410%17%22%9%
2112
November1st to 15thNight
33%6%11%20%20%7%
2101
16th to endNight
32%6%10%20%17%11%
2211
December1st to 15thNight
36%6%12%24%12%6%
2340
16th to endNight
37%6%13%22%12%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
15%12%34%22%11%4
90
16th to endDay
14%16%34%21%9%3
96
February1st to 15thDay
422%28%22%18%3
90
16th to endDay
13%10%38%26%9%1
161
March1st to 15thDay
7%9%30%33%16%4
270
16th to endDay
8%6%26%28%24%5%
288
April1st to 15thDay
5%8%25%25%25%9%
270
16th to endDay
7%417%26%24%19%
270
May1st to 15thDay
6%315%23%29%20%
288
16th to endDay
6%26%24%30%29%
331
June1st to 15thDay
13%17%20%24%31%
315
16th to endDay
8%5%12%25%46%
315
July1st to 15thDay
5%110%25%56%
305
16th to endDay
10%1214%27%44%
326
August1st to 15thDay
6%5%13%24%49%
313
16th to endDay
12%1413%18%48%
332
September1st to 15thDay
14%26%13%26%37%
315
16th to endDay
11%5%13%32%36%
259
October1st to 15thDay
12%312%25%32%13%
255
16th to endDay
10%320%27%26%9%
272
November1st to 15thDay
6%122%27%32%9%
265
16th to endDay
11%326%35%18%4
216
December1st to 15thDay
8%6%43%33%7%
90
16th to endDay
3426%44%17%4
96
January1st to 15thNight
11%7%30%32%16%1
720
16th to endNight
15%7%29%35%11%
768
February1st to 15thNight
12%5%34%33%12%1
704
16th to endNight
9%7%32%40%8%
631
March1st to 15thNight
6%6%29%43%12%1
720
16th to endNight
7%5%29%37%19%1
768
April1st to 15thNight
7%230%39%19%1
718
16th to endNight
7%323%42%21%
720
May1st to 15thNight
7%214%45%28%2
597
16th to endNight
8%18%30%42%8%
563
June1st to 15thNight
10%7%26%44%10%
540
16th to endNight
8%1217%48%20%
540
July1st to 15thNight
10%114%47%25%
510
16th to endNight
41114%53%23%
564
August1st to 15thNight
4117%51%25%
539
16th to endNight
12%15%16%42%21%
738
September1st to 15thNight
11%15%18%44%18%
720
16th to endNight
14%15%22%43%12%
665
October1st to 15thNight
9%19%34%37%7%
660
16th to endNight
12%313%35%31%5%
704
November1st to 15thNight
5%322%39%26%2
700
16th to endNight
9%424%37%20%1
720
December1st to 15thNight
11%425%33%23%1
720
16th to endNight
10%5%24%35%21%1
768
Page generated at 2017-09-18 08:38:20. Version ac04

Copyright 2017 A. Danko


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