Dacula
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dacula 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
48%
16917
23%
51106
15%
16874
56%
16874
28%
31542

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
25%
780
23%
2522
9%
776
41%
776
21%
1555
January16th to endNight
26%
832
26%
2671
12%
832
43%
832
22%
1640
February1st to 15thNight
29%
764
25%
2291
9%
761
45%
761
25%
1418
February16th to endNight
23%
683
24%
2049
8%
683
38%
683
24%
1287
March1st to 15thNight
30%
780
25%
2223
11%
780
43%
780
28%
1382
March16th to endNight
37%
832
22%
2288
11%
832
45%
832
29%
1433
April1st to 15thNight
43%
714
25%
2077
15%
714
53%
714
35%
1209
April16th to endNight
48%
579
25%
1806
16%
579
58%
579
33%
1038
May1st to 15thNight
51%
585
21%
1755
12%
585
58%
585
30%
1071
May16th to endNight
58%
609
20%
1827
13%
609
62%
609
28%
1172
June1st to 15thNight
70%
585
17%
1755
15%
585
71%
585
30%
1097
June16th to endNight
76%
585
16%
1755
12%
585
78%
585
32%
1063
July1st to 15thNight
69%
555
13%
1665
11%
555
70%
555
26%
1096
July16th to endNight
76%
612
15%
1739
12%
579
78%
579
28%
1117
August1st to 15thNight
67%
575
18%
1721
18%
572
67%
572
26%
1146
August16th to endNight
66%
621
16%
2070
19%
621
66%
621
22%
1370
September1st to 15thNight
63%
777
19%
2142
17%
777
64%
777
26%
1467
September16th to endNight
61%
777
23%
2145
19%
777
65%
777
31%
1384
October1st to 15thNight
55%
752
31%
2089
24%
752
62%
752
37%
1237
October16th to endNight
51%
768
36%
2304
25%
768
65%
768
38%
1262
November1st to 15thNight
51%
760
30%
2438
25%
760
62%
760
36%
1329
November16th to endNight
42%
780
29%
2535
19%
780
56%
780
31%
1417
December1st to 15thNight
35%
780
24%
2535
14%
780
48%
780
25%
1548
December16th to endNight
30%
832
21%
2704
13%
832
41%
832
20%
1804

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
13%5%244345%5%7%42%
52026
Night
12%42442445%7%45%
51305
TransparencyDay
39%7%12%19%17%4
51727
Night
36%6%11%20%19%6%
51108
SeeingDay
15%7%19%22%22%12%
6798
Night
14%7%22%28%22%4
16919

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
16%6%3441444444%
1746
16th to endDay
18%5%24313345%46%
1904
February1st to 15thDay
18%5%14424445%43%
1900
16th to endDay
19%6%14323445%42%
1710
March1st to 15thDay
16%5%235%23347%45%
2067
16th to endDay
16%42442345%8%42%
2287
April1st to 15thDay
12%5%25%434446%45%
2211
16th to endDay
11%42432345%7%49%
2427
May1st to 15thDay
11%42442345%7%47%
2526
16th to endDay
11%5%25%5%35%46%9%38%
2639
June1st to 15thDay
8%4246%45%6%8%11%35%
2535
16th to endDay
42135%46%6%8%10%44%
2535
July1st to 15thDay
10%5%25%5%5%6%8%8%10%30%
2535
16th to endDay
7%5%26%5%5%7%8%8%10%31%
2673
August1st to 15thDay
10%5%25%7%47%6%7%10%32%
2477
16th to endDay
13%7%36%5%46%7%6%10%28%
2474
September1st to 15thDay
12%5%25%6%45%6%7%8%35%
2145
16th to endDay
14%5%244345%5%7%43%
2145
October1st to 15thDay
12%41331334455%
2041
16th to endDay
11%41331233460%
1920
November1st to 15thDay
12%423323445%54%
1747
16th to endDay
14%5%14323336%50%
1755
December1st to 15thDay
19%5%15%5%2245%5%41%
1755
16th to endDay
23%8%35%42333436%
1872
January1st to 15thNight
17%6%24324245%45%
2522
16th to endNight
17%5%24423345%45%
2671
February1st to 15thNight
17%424423236%47%
2283
16th to endNight
17%414433345%45%
2049
March1st to 15thNight
13%5%24423445%48%
2223
16th to endNight
13%5%1433345%6%47%
2288
April1st to 15thNight
12%41332345%7%51%
2077
16th to endNight
9%425%32345%6%51%
1806
May1st to 15thNight
9%4245%25%5%5%8%47%
1754
16th to endNight
10%5%245%35%5%6%7%44%
1826
June1st to 15thNight
6%324445%6%8%12%40%
1755
16th to endNight
42135%36%7%9%11%42%
1755
July1st to 15thNight
7%425%7%36%6%8%11%35%
1755
16th to endNight
43245%48%8%9%14%34%
1847
August1st to 15thNight
8%5%25%6%346%7%11%37%
1732
16th to endNight
11%5%25%5%45%6%7%10%35%
2070
September1st to 15thNight
8%426%7%36%5%6%9%39%
2142
16th to endNight
12%4245%2445%7%45%
2145
October1st to 15thNight
11%414413347%53%
2089
16th to endNight
10%31331333461%
2304
November1st to 15thNight
11%313323246%57%
2438
16th to endNight
14%413323345%53%
2535
December1st to 15thNight
16%5%25%413347%45%
2535
16th to endNight
21%7%24433346%36%
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
41%410%16%23%4
1747
16th to endDay
39%36%20%21%8%
1904
February1st to 15thDay
41%48%19%22%3
1902
16th to endDay
42%47%19%19%6%
1710
March1st to 15thDay
39%410%19%20%6%
2067
16th to endDay
40%5%12%20%16%3
2288
April1st to 15thDay
38%410%22%19%4
2211
16th to endDay
33%6%9%21%23%5%
2427
May1st to 15thDay
34%6%13%22%19%2
2526
16th to endDay
40%9%13%23%12%1
2643
June1st to 15thDay
37%10%19%21%7%1
2535
16th to endDay
30%9%17%25%13%2
2535
July1st to 15thDay
40%12%19%18%6%1
2396
16th to endDay
41%12%17%19%7%1
2518
August1st to 15thDay
43%11%16%17%9%1
2464
16th to endDay
48%10%15%15%9%
2474
September1st to 15thDay
43%9%14%16%13%2
2145
16th to endDay
39%6%11%19%18%3
2145
October1st to 15thDay
32%411%19%26%6%
2041
16th to endDay
28%35%18%31%12%
1920
November1st to 15thDay
31%48%15%30%9%
1747
16th to endDay
35%36%17%28%8%
1755
December1st to 15thDay
43%48%19%15%8%
1755
16th to endDay
51%38%17%13%6%
1872
January1st to 15thNight
41%37%18%23%5%
2522
16th to endNight
41%25%18%23%8%
2671
February1st to 15thNight
39%37%19%21%9%
2292
16th to endNight
39%47%20%22%6%
2049
March1st to 15thNight
36%49%18%21%9%
2223
16th to endNight
36%5%10%21%21%5%
2288
April1st to 15thNight
31%410%23%22%7%
2077
16th to endNight
31%5%10%21%21%8%
1806
May1st to 15thNight
34%7%14%20%19%3
1755
16th to endNight
36%8%12%24%13%3
1828
June1st to 15thNight
32%10%19%25%9%1
1755
16th to endNight
28%12%19%23%14%2
1755
July1st to 15thNight
36%12%21%20%7%2
1665
16th to endNight
33%12%23%19%8%2
1739
August1st to 15thNight
38%10%16%21%11%1
1721
16th to endNight
40%10%18%17%11%
2070
September1st to 15thNight
39%10%13%18%14%3
2142
16th to endNight
35%8%13%19%17%5%
2145
October1st to 15thNight
31%5%11%18%25%7%
2089
16th to endNight
28%3417%32%13%
2304
November1st to 15thNight
29%36%18%28%12%
2438
16th to endNight
33%36%18%26%10%
2535
December1st to 15thNight
39%49%21%18%7%
2535
16th to endNight
47%38%17%17%5%
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
18%18%37%21%3
135
16th to endDay
15%29%33%18%21
144
February1st to 15thDay
22%22%35%17%1
135
16th to endDay
28%15%40%13%2
120
March1st to 15thDay
18%19%32%20%8%
252
16th to endDay
17%15%31%22%12%1
352
April1st to 15thDay
17%13%26%21%17%3
330
16th to endDay
15%9%22%28%21%2
319
May1st to 15thDay
13%7%26%19%20%11%
348
16th to endDay
20%217%23%22%14%
395
June1st to 15thDay
11%28%23%31%22%
375
16th to endDay
7%113%27%26%24%
375
July1st to 15thDay
11%17%22%30%26%
365
16th to endDay
9%6%20%38%23%
390
August1st to 15thDay
18%17%22%27%23%
358
16th to endDay
16%19%24%26%21%
396
September1st to 15thDay
12%312%21%31%18%
375
16th to endDay
16%211%24%31%13%
374
October1st to 15thDay
16%222%24%21%13%
345
16th to endDay
12%8%19%25%27%5%
336
November1st to 15thDay
25%10%23%18%20%1
165
16th to endDay
10%10%28%32%11%5%
135
December1st to 15thDay
29%14%26%22%5%
135
16th to endDay
31%20%30%13%2
144
January1st to 15thNight
21%18%29%23%7%
780
16th to endNight
19%16%34%23%5%
832
February1st to 15thNight
19%15%32%28%4
764
16th to endNight
18%17%36%23%3
683
March1st to 15thNight
17%13%35%28%5%
780
16th to endNight
15%12%29%28%12%
832
April1st to 15thNight
14%11%29%28%15%
714
16th to endNight
11%6%29%30%20%1
579
May1st to 15thNight
11%426%29%24%3
585
16th to endNight
13%116%30%32%5%
611
June1st to 15thNight
7%13%32%34%11%
585
16th to endNight
5%9%33%38%12%
585
July1st to 15thNight
9%15%25%45%13%
555
16th to endNight
5%6%26%49%10%
612
August1st to 15thNight
11%16%26%43%10%
575
16th to endNight
14%7%26%40%10%
621
September1st to 15thNight
11%19%24%42%9%
777
16th to endNight
16%112%32%32%3
777
October1st to 15thNight
14%320%26%26%7%
752
16th to endNight
11%7%24%29%24%3
768
November1st to 15thNight
13%6%25%30%23%1
760
16th to endNight
16%10%27%28%16%1
780
December1st to 15thNight
17%10%31%28%11%
780
16th to endNight
24%11%29%28%5%
832
Page generated at 2018-10-09 10:39:11. Version ac04

Copyright 2018 A. Danko


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