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 2018-10-08.

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%
17412
21%
51090
16%
17372
64%
17372
29%
32171

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
43%
779
20%
2522
14%
776
53%
776
24%
1576
January16th to endNight
41%
832
24%
2694
18%
832
52%
832
28%
1627
February1st to 15thNight
42%
761
22%
2285
14%
760
52%
760
31%
1374
February16th to endNight
46%
683
27%
1961
16%
683
57%
683
34%
1156
March1st to 15thNight
51%
780
29%
2145
17%
780
62%
780
43%
1193
March16th to endNight
53%
832
26%
2288
18%
832
59%
832
41%
1309
April1st to 15thNight
53%
778
24%
2141
16%
778
59%
778
39%
1254
April16th to endNight
59%
771
26%
1942
17%
771
63%
771
42%
1166
May1st to 15thNight
68%
646
25%
1816
19%
646
71%
646
41%
1027
May16th to endNight
70%
609
20%
1826
16%
609
71%
609
29%
1174
June1st to 15thNight
70%
585
13%
1755
11%
585
70%
585
24%
1205
June16th to endNight
72%
585
8%
1755
7%
585
72%
585
23%
1249
July1st to 15thNight
73%
555
8%
1665
6%
555
73%
555
22%
1184
July16th to endNight
75%
612
8%
1739
8%
579
77%
579
21%
1226
August1st to 15thNight
78%
575
10%
1715
9%
572
78%
572
26%
1159
August16th to endNight
65%
800
9%
2172
9%
800
66%
800
22%
1554
September1st to 15thNight
67%
780
9%
2145
8%
780
68%
780
19%
1576
September16th to endNight
64%
777
12%
2145
12%
777
65%
777
21%
1551
October1st to 15thNight
68%
752
26%
2160
26%
752
70%
752
31%
1348
October16th to endNight
62%
768
28%
2304
27%
768
67%
768
33%
1375
November1st to 15thNight
60%
760
26%
2281
21%
760
68%
760
34%
1343
November16th to endNight
55%
780
29%
2395
23%
780
64%
780
33%
1409
December1st to 15thNight
53%
780
26%
2535
23%
780
61%
780
29%
1512
December16th to endNight
53%
832
24%
2704
21%
832
59%
832
28%
1624

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%46%6%6%8%35%
52030
Night
7%425%5%35%5%6%9%43%
51297
TransparencyDay
43%9%14%16%12%5%
51731
Night
34%8%16%20%13%6%
51100
SeeingDay
9%416%23%23%23%
7259
Night
9%318%31%29%7%
17419

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%7%36%5%35%6%48%38%
1746
16th to endDay
10%5%25%42445%7%45%
1879
February1st to 15thDay
10%5%35%5%35%5%47%42%
1900
16th to endDay
8%425%7%3445%7%46%
1797
March1st to 15thDay
5%325%6%345%48%50%
2145
16th to endDay
8%425%6%346%46%47%
2287
April1st to 15thDay
7%3245%45%5%6%9%44%
2137
16th to endDay
5%425%5%46%6%6%8%44%
2292
May1st to 15thDay
7%315%5%35%5%6%7%46%
2474
16th to endDay
9%5%27%6%5%7%6%8%8%31%
2639
June1st to 15thDay
9%6%37%8%6%8%7%8%9%25%
2535
16th to endDay
8%6%48%9%5%8%8%7%8%25%
2535
July1st to 15thDay
8%6%38%9%6%9%8%8%8%21%
2535
16th to endDay
8%6%48%10%6%9%7%7%8%21%
2673
August1st to 15thDay
5%5%310%10%6%8%8%8%11%22%
2487
16th to endDay
10%6%48%9%6%8%7%7%8%22%
2365
September1st to 15thDay
8%6%38%10%6%7%8%8%9%21%
2145
16th to endDay
10%7%39%9%6%6%6%7%9%22%
2145
October1st to 15thDay
9%5%38%7%46%6%7%8%33%
1969
16th to endDay
10%5%25%5%35%5%5%7%44%
1920
November1st to 15thDay
6%425%5%46%5%6%8%44%
1907
16th to endDay
9%6%36%5%35%5%47%42%
1891
December1st to 15thDay
10%6%36%5%3446%7%40%
1755
16th to endDay
7%5%25%5%35%5%5%8%44%
1872
January1st to 15thNight
11%6%35%4345%5%9%41%
2522
16th to endNight
12%5%3442345%8%44%
2694
February1st to 15thNight
10%5%2443445%6%49%
2283
16th to endNight
7%3245%24447%52%
1961
March1st to 15thNight
5%32332445%7%56%
2145
16th to endNight
6%32442335%7%57%
2288
April1st to 15thNight
6%41433446%8%52%
2141
16th to endNight
6%31442345%8%53%
1942
May1st to 15thNight
5%3144245%48%55%
1816
16th to endNight
7%325%6%35%6%7%9%41%
1826
June1st to 15thNight
7%5%27%5%37%6%8%11%34%
1755
16th to endNight
6%5%27%6%45%7%8%11%33%
1755
July1st to 15thNight
7%425%6%36%7%9%12%32%
1755
16th to endNight
45%36%7%48%7%8%11%31%
1847
August1st to 15thNight
3327%7%46%7%10%11%35%
1726
16th to endNight
9%436%6%35%6%8%12%31%
2172
September1st to 15thNight
7%5%25%6%47%7%8%12%30%
2145
16th to endNight
9%7%26%7%48%7%8%10%28%
2145
October1st to 15thNight
6%425%5%35%6%6%9%43%
2160
16th to endNight
8%425%5%2345%9%48%
2304
November1st to 15thNight
4425%5%35%46%8%47%
2281
16th to endNight
8%424325%46%8%48%
2395
December1st to 15thNight
9%425%435%45%8%46%
2535
16th to endNight
8%4245%35%5%5%8%45%
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
43%5%9%16%17%7%
1747
16th to endDay
36%5%9%17%20%10%
1879
February1st to 15thDay
40%5%9%12%18%12%
1902
16th to endDay
37%5%9%17%20%9%
1797
March1st to 15thDay
31%5%10%23%18%10%
2145
16th to endDay
35%5%12%19%19%7%
2288
April1st to 15thDay
34%7%11%19%20%6%
2137
16th to endDay
34%6%10%21%17%9%
2292
May1st to 15thDay
33%7%11%20%19%7%
2474
16th to endDay
44%8%14%17%11%2
2643
June1st to 15thDay
48%10%18%17%3
2535
16th to endDay
50%12%20%12%2
2535
July1st to 15thDay
51%15%20%11%1
2396
16th to endDay
53%14%18%12%1
2518
August1st to 15thDay
49%15%23%10%
2474
16th to endDay
53%14%20%11%1
2365
September1st to 15thDay
52%16%17%10%3
2145
16th to endDay
52%10%16%15%41
2145
October1st to 15thDay
44%8%10%15%14%7%
1969
16th to endDay
38%5%7%15%21%11%
1920
November1st to 15thDay
35%5%10%20%20%6%
1907
16th to endDay
40%5%8%18%17%9%
1891
December1st to 15thDay
41%6%12%19%14%6%
1755
16th to endDay
36%6%15%20%13%7%
1872
January1st to 15thNight
40%5%10%19%15%7%
2522
16th to endNight
38%49%18%20%9%
2694
February1st to 15thNight
34%5%11%16%17%14%
2292
16th to endNight
31%5%13%18%22%7%
1961
March1st to 15thNight
25%414%27%19%8%
2145
16th to endNight
26%5%13%24%19%10%
2288
April1st to 15thNight
27%7%13%25%17%8%
2141
16th to endNight
28%5%12%26%19%7%
1942
May1st to 15thNight
26%6%15%25%18%7%
1817
16th to endNight
35%9%15%22%14%1
1828
June1st to 15thNight
39%12%21%23%3
1755
16th to endNight
39%14%24%16%4
1755
July1st to 15thNight
38%16%28%13%2
1665
16th to endNight
39%16%27%15%1
1739
August1st to 15thNight
34%15%34%14%1
1715
16th to endNight
41%13%27%15%1
2172
September1st to 15thNight
40%18%21%14%4
2145
16th to endNight
44%11%20%17%41
2145
October1st to 15thNight
33%8%12%21%16%6%
2160
16th to endNight
34%49%17%22%10%
2304
November1st to 15thNight
31%6%11%22%20%6%
2281
16th to endNight
32%6%10%21%18%10%
2395
December1st to 15thNight
35%6%13%24%12%7%
2535
16th to endNight
35%6%13%24%12%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%15%40%16%7%2
135
16th to endDay
12%15%40%22%6%2
144
February1st to 15thDay
5%17%32%25%15%3
135
16th to endDay
10%8%33%28%17%1
207
March1st to 15thDay
6%12%30%33%14%3
330
16th to endDay
8%7%28%29%21%5%
352
April1st to 15thDay
6%7%27%26%23%7%
330
16th to endDay
8%321%27%21%16%
319
May1st to 15thDay
9%317%25%25%18%
348
16th to endDay
11%28%23%27%25%
395
June1st to 15thDay
12%18%21%24%32%
375
16th to endDay
8%5%12%26%47%
375
July1st to 15thDay
5%110%25%56%
365
16th to endDay
10%1317%26%41%
390
August1st to 15thDay
5%5%14%25%48%
358
16th to endDay
10%1413%19%49%
396
September1st to 15thDay
12%25%16%26%35%
375
16th to endDay
8%5%19%31%34%
374
October1st to 15thDay
11%313%30%29%11%
345
16th to endDay
10%6%21%29%23%8%
336
November1st to 15thDay
5%220%32%30%8%
325
16th to endDay
10%324%38%19%3
271
December1st to 15thDay
8%7%44%28%10%1
135
16th to endDay
2327%46%16%3
144
January1st to 15thNight
11%7%31%33%15%1
780
16th to endNight
14%7%29%35%11%
832
February1st to 15thNight
12%434%34%12%1
764
16th to endNight
9%7%31%40%10%
683
March1st to 15thNight
6%6%31%42%12%1
780
16th to endNight
6%5%29%38%18%1
832
April1st to 15thNight
7%329%38%19%1
778
16th to endNight
7%323%43%20%
771
May1st to 15thNight
7%213%46%28%1
647
16th to endNight
9%18%30%42%7%
611
June1st to 15thNight
10%7%25%44%10%
585
16th to endNight
8%1216%48%23%
585
July1st to 15thNight
10%113%46%27%
555
16th to endNight
41214%53%23%
612
August1st to 15thNight
4116%51%25%
575
16th to endNight
12%15%15%43%22%
800
September1st to 15thNight
11%1419%44%19%
780
16th to endNight
12%1422%44%13%
777
October1st to 15thNight
9%19%34%37%6%
752
16th to endNight
12%214%36%30%4
768
November1st to 15thNight
5%222%39%27%2
760
16th to endNight
9%424%38%21%1
780
December1st to 15thNight
10%424%34%23%1
780
16th to endNight
9%5%24%35%22%1
832
Page generated at 2018-10-09 10:39:14. Version ac04

Copyright 2018 A. Danko


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