Oconee Observing Field
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oconee Observing Field clear sky chart from 2005-11-06 to 2024-01-14.

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
47%
24036
22%
74413
14%
23980
55%
23980
26%
46256

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 10thNight
22%
760
23%
2459
8%
757
41%
757
19%
1511
January11th to 20thNight
29%
736
26%
2391
13%
736
46%
736
22%
1480
January21st to endNight
24%
792
26%
2565
11%
792
42%
792
21%
1580
February1st to 10thNight
31%
720
24%
2160
11%
720
45%
720
24%
1362
February11th to 20thNight
25%
703
22%
2098
8%
699
39%
699
22%
1341
February21st to endNight
25%
592
24%
1776
9%
592
38%
592
22%
1156
March1st to 10thNight
33%
720
27%
2038
14%
720
44%
720
28%
1246
March11th to 20thNight
31%
720
22%
1980
8%
720
42%
720
26%
1272
March21st to endNight
32%
792
23%
2178
9%
792
43%
792
27%
1367
April1st to 10thNight
36%
720
25%
1980
14%
720
45%
720
31%
1204
April11th to 20thNight
43%
621
27%
1838
15%
621
54%
621
33%
1055
April21st to endNight
49%
540
31%
1620
19%
540
59%
540
36%
910
May1st to 10thNight
52%
540
24%
1620
14%
540
61%
540
36%
918
May11th to 20thNight
57%
531
16%
1592
10%
531
60%
531
27%
1027
May21st to endNight
61%
582
21%
1744
17%
582
64%
582
29%
1100
June1st to 10thNight
63%
540
15%
1620
12%
540
64%
540
26%
1080
June11th to 20thNight
68%
540
17%
1620
14%
540
70%
540
34%
977
June21st to endNight
70%
540
14%
1620
11%
540
71%
540
28%
1051
July1st to 10thNight
68%
525
13%
1575
11%
525
69%
525
23%
1078
July11th to 20thNight
72%
522
11%
1566
10%
522
73%
522
25%
1050
July21st to endNight
73%
591
14%
1672
12%
558
74%
558
26%
1118
August1st to 10thNight
69%
537
12%
1600
12%
534
69%
534
21%
1126
August11th to 20thNight
64%
534
16%
1639
16%
534
65%
534
22%
1130
August21st to endNight
62%
638
14%
2024
14%
638
63%
638
20%
1387
September1st to 10thNight
65%
720
17%
1980
15%
720
65%
720
27%
1321
September11th to 20thNight
61%
720
20%
1980
16%
720
63%
720
29%
1308
September21st to endNight
58%
720
25%
1980
18%
720
63%
720
31%
1257
October1st to 10thNight
57%
720
27%
1980
21%
720
64%
720
37%
1186
October11th to 20thNight
52%
720
31%
2137
25%
720
62%
720
36%
1220
October21st to endNight
50%
792
32%
2376
25%
792
62%
792
35%
1334
November1st to 10thNight
52%
740
30%
2274
24%
740
61%
740
35%
1265
November11th to 20thNight
41%
760
28%
2470
19%
760
54%
760
29%
1398
November21st to endNight
40%
760
26%
2470
17%
760
53%
760
28%
1464
December1st to 10thNight
35%
760
27%
2470
14%
760
51%
760
22%
1524
December11th to 20thNight
36%
759
27%
2903
16%
758
48%
758
21%
1671
December21st to endNight
30%
829
15%
4418
12%
817
42%
817
11%
2782

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%25%5%35%5%6%8%43%
74895
Night
13%5%25%5%345%6%7%45%
74875
TransparencyDay
39%7%11%19%18%5%
74618
Night
37%7%11%19%20%7%
74671
SeeingDay
16%9%23%24%19%9%
13938
Night
15%9%22%30%20%3
24046

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 10thDay
17%7%25%32445%6%46%
1706
11th to 20thDay
15%7%34425%446%45%
1647
21st to endDay
18%7%24423445%45%
1789
February1st to 10thDay
17%7%36%426%45%7%39%
1800
11th to 20thDay
21%6%2342345%5%45%
1748
21st to endDay
19%6%25%5%345%5%6%40%
1480
March1st to 10thDay
14%5%24434446%51%
1921
11th to 20thDay
17%5%35%4245%5%6%44%
1980
21st to endDay
15%6%245%35%5%5%7%43%
2178
April1st to 10thDay
13%435%5%3345%6%50%
1980
11th to 20thDay
12%5%25%5%3445%7%48%
2082
21st to endDay
8%42443445%8%53%
2340
May1st to 10thDay
9%424325%5%5%8%52%
2340
11th to 20thDay
10%6%36%5%46%6%6%8%41%
2301
21st to endDay
10%5%25%6%36%5%7%8%43%
2531
June1st to 10thDay
11%5%26%7%46%6%8%10%34%
2340
11th to 20thDay
6%4246%36%6%7%12%43%
2340
21st to endDay
6%425%7%5%7%7%8%12%37%
2340
July1st to 10thDay
7%5%37%6%5%8%8%9%11%31%
2340
11th to 20thDay
7%5%37%7%47%7%8%11%33%
2340
21st to endDay
7%436%8%5%7%8%9%12%32%
2547
August1st to 10thDay
9%5%38%7%5%8%7%9%11%28%
2327
11th to 20thDay
11%5%36%8%5%7%6%6%10%33%
2258
21st to endDay
13%7%37%7%47%7%7%8%31%
2311
September1st to 10thDay
11%5%26%6%46%5%7%9%39%
1980
11th to 20thDay
14%5%35%5%35%5%5%8%42%
1980
21st to endDay
14%7%25%5%3445%6%45%
1980
October1st to 10thDay
13%6%2442345%7%51%
1980
11th to 20thDay
14%32332345%6%56%
1822
21st to endDay
11%425%424435%55%
1980
November1st to 10thDay
11%434424445%55%
1800
11th to 20thDay
14%424323346%55%
1710
21st to endDay
14%5%24435%45%7%48%
1710
December1st to 10thDay
18%6%35%5%35%5%5%6%39%
1710
11th to 20thDay
18%6%2442435%6%47%
2153
21st to endDay
21%7%34424346%41%
3124
January1st to 10thNight
16%7%35%424346%45%
2459
11th to 20thNight
17%7%2442445%6%45%
2391
21st to endNight
17%6%35%5%23445%47%
2565
February1st to 10thNight
17%5%35%43445%6%45%
2160
11th to 20thNight
19%6%24424446%45%
2098
21st to endNight
16%6%26%5%34446%44%
1776
March1st to 10thNight
12%6%35%434446%50%
2038
11th to 20thNight
15%5%245%2445%7%46%
1980
21st to endNight
13%5%25%4245%6%7%47%
2178
April1st to 10thNight
12%4244345%5%7%50%
1980
11th to 20thNight
13%5%2332345%8%52%
1838
21st to endNight
8%3144345%5%7%55%
1620
May1st to 10thNight
7%5%244345%5%8%55%
1620
11th to 20thNight
8%426%6%47%6%7%8%43%
1592
21st to endNight
11%5%25%5%45%6%7%9%43%
1744
June1st to 10thNight
9%6%35%5%46%7%7%12%35%
1620
11th to 20thNight
5%4246%45%6%8%12%45%
1620
21st to endNight
7%5%25%6%47%8%9%11%38%
1620
July1st to 10thNight
8%426%6%46%7%9%12%35%
1620
11th to 20thNight
6%5%26%6%46%8%10%14%34%
1620
21st to endNight
6%425%5%48%6%10%13%36%
1771
August1st to 10thNight
7%5%36%6%5%8%8%9%12%30%
1611
11th to 20thNight
10%437%6%46%6%9%9%36%
1639
21st to endNight
11%7%36%7%45%6%8%9%34%
2024
September1st to 10thNight
10%5%25%6%45%6%6%11%39%
1980
11th to 20thNight
12%5%25%6%445%6%8%43%
1980
21st to endNight
11%5%26%5%345%5%6%48%
1980
October1st to 10thNight
12%5%24424446%53%
1980
11th to 20thNight
13%323424445%57%
2137
21st to endNight
11%324434445%56%
2376
November1st to 10thNight
10%5%25%32335%6%56%
2274
11th to 20thNight
14%5%24333345%54%
2470
21st to endNight
14%4245%3445%6%49%
2470
December1st to 10thNight
16%6%345%245%5%7%45%
2470
11th to 20thNight
17%6%2432335%5%51%
3042
21st to endNight
18%9%36%5%35%45%6%36%
4532

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 10thDay
40%5%8%18%25%4
1707
11th to 20thDay
41%47%19%23%6%
1647
21st to endDay
42%35%18%25%7%
1789
February1st to 10thDay
45%49%18%18%7%
1800
11th to 20thDay
41%35%21%22%6%
1758
21st to endDay
44%5%8%14%21%9%
1480
March1st to 10thDay
36%47%18%23%12%
1921
11th to 20thDay
41%6%11%18%18%7%
1980
21st to endDay
40%6%9%21%18%5%
2178
April1st to 10thDay
36%410%21%21%8%
1980
11th to 20thDay
35%5%9%20%21%10%
2082
21st to endDay
29%5%11%26%25%4
2340
May1st to 10thDay
29%7%13%23%23%5%
2340
11th to 20thDay
40%8%16%19%15%2
2305
21st to endDay
37%8%11%24%18%2
2531
June1st to 10thDay
42%10%16%19%12%2
2340
11th to 20thDay
31%10%18%26%13%1
2340
21st to endDay
36%12%18%18%13%3
2340
July1st to 10thDay
40%14%19%17%8%3
2275
11th to 20thDay
40%13%19%18%7%2
2271
21st to endDay
39%14%20%20%7%1
2405
August1st to 10thDay
45%13%18%19%5%
2314
11th to 20thDay
44%12%16%17%9%1
2258
21st to endDay
49%9%16%15%9%2
2311
September1st to 10thDay
40%9%13%17%17%4
1980
11th to 20thDay
40%8%9%19%22%3
1980
21st to endDay
39%7%10%20%19%6%
1980
October1st to 10thDay
33%5%9%20%26%7%
1980
11th to 20thDay
30%48%24%26%8%
1822
21st to endDay
32%4415%32%13%
1980
November1st to 10thDay
32%47%15%27%13%
1800
11th to 20thDay
33%37%21%25%12%
1710
21st to endDay
36%5%8%19%24%7%
1710
December1st to 10thDay
45%6%8%16%18%7%
1710
11th to 20thDay
40%46%15%26%9%
2150
21st to endDay
44%47%18%22%4
3124
January1st to 10thNight
41%46%19%24%6%
2459
11th to 20thNight
40%46%19%22%7%
2391
21st to endNight
41%4418%24%10%
2565
February1st to 10thNight
40%48%18%20%9%
2160
11th to 20thNight
41%5%5%18%22%9%
2099
21st to endNight
42%5%7%16%19%11%
1776
March1st to 10thNight
36%48%17%22%14%
2038
11th to 20thNight
38%6%12%16%21%8%
1980
21st to endNight
36%6%10%21%20%8%
2178
April1st to 10thNight
33%5%9%21%22%10%
1980
11th to 20thNight
31%5%7%24%22%11%
1838
21st to endNight
28%7%11%24%23%8%
1620
May1st to 10thNight
28%6%13%24%21%7%
1620
11th to 20thNight
37%10%16%19%16%3
1593
21st to endNight
36%9%12%22%18%3
1745
June1st to 10thNight
39%10%19%18%13%1
1620
11th to 20thNight
30%10%20%27%11%2
1620
21st to endNight
34%12%20%18%12%3
1620
July1st to 10thNight
38%14%20%17%8%4
1575
11th to 20thNight
35%14%25%16%7%2
1566
21st to endNight
33%16%23%20%7%1
1672
August1st to 10thNight
40%15%18%21%5%
1600
11th to 20thNight
40%13%18%18%9%2
1639
21st to endNight
44%11%19%15%10%2
2024
September1st to 10thNight
38%11%16%17%15%4
1980
11th to 20thNight
39%8%13%17%18%5%
1980
21st to endNight
36%7%11%17%22%7%
1980
October1st to 10thNight
33%410%18%28%7%
1980
11th to 20thNight
31%47%20%27%10%
2137
21st to endNight
30%45%17%29%15%
2376
November1st to 10thNight
30%48%17%26%15%
2274
11th to 20thNight
34%36%17%25%14%
2470
21st to endNight
36%47%17%25%9%
2470
December1st to 10thNight
38%6%9%19%21%7%
2470
11th to 20thNight
38%47%15%28%9%
3044
21st to endNight
48%5%6%19%19%3
4532

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 10thDay
25%23%38%12%2
270
11th to 20thDay
22%22%35%13%7%1
249
21st to endDay
26%26%34%10%4
264
February1st to 10thDay
28%18%37%13%4
240
11th to 20thDay
36%17%37%10%
240
21st to endDay
29%17%43%7%4
198
March1st to 10thDay
19%19%32%24%6%1
361
11th to 20thDay
22%15%36%18%7%1
420
21st to endDay
21%18%33%20%8%1
462
April1st to 10thDay
21%15%29%24%11%1
420
11th to 20thDay
13%17%29%22%16%3
412
21st to endDay
13%11%27%27%18%3
420
May1st to 10thDay
13%12%29%28%12%6%
423
11th to 20thDay
14%421%29%24%8%
447
21st to endDay
14%5%16%29%24%13%
485
June1st to 10thDay
14%215%31%26%13%
450
11th to 20thDay
7%416%26%27%20%
450
21st to endDay
8%218%29%26%17%
450
July1st to 10thDay
7%210%26%33%22%
445
11th to 20thDay
9%29%22%39%20%
444
21st to endDay
6%29%25%38%19%
488
August1st to 10thDay
11%315%22%31%17%
446
11th to 20thDay
11%28%27%33%20%
439
21st to endDay
16%312%25%29%16%
495
September1st to 10thDay
12%411%28%31%14%
450
11th to 20thDay
16%215%26%30%12%
450
21st to endDay
15%416%30%26%9%
450
October1st to 10thDay
17%422%29%19%8%
450
11th to 20thDay
15%8%23%26%21%7%
450
21st to endDay
15%10%26%26%18%5%
495
November1st to 10thDay
17%8%28%28%17%3
398
11th to 20thDay
18%14%37%24%5%1
270
21st to endDay
16%14%32%27%9%2
270
December1st to 10thDay
27%16%34%16%7%1
270
11th to 20thDay
27%14%37%16%6%
270
21st to endDay
29%17%33%14%5%2
297
January1st to 10thNight
22%18%33%21%5%
760
11th to 20thNight
21%16%30%26%7%
736
21st to endNight
20%18%34%24%3
792
February1st to 10thNight
21%14%29%29%6%
720
11th to 20thNight
23%16%33%26%3
703
21st to endNight
20%15%36%27%2
592
March1st to 10thNight
15%18%30%33%4
720
11th to 20thNight
18%13%32%27%10%1
720
21st to endNight
17%15%32%27%9%1
792
April1st to 10thNight
16%15%30%27%12%
720
11th to 20thNight
16%11%27%30%15%1
621
21st to endNight
9%7%28%38%16%1
540
May1st to 10thNight
9%7%26%39%16%1
540
11th to 20thNight
11%321%37%24%4
531
21st to endNight
12%214%32%33%6%
584
June1st to 10thNight
10%212%41%31%4
540
11th to 20thNight
5%315%32%34%11%
540
21st to endNight
8%210%37%37%6%
540
July1st to 10thNight
8%29%28%39%14%
525
11th to 20thNight
7%17%27%46%11%
522
21st to endNight
5%19%28%49%7%
591
August1st to 10thNight
9%17%33%41%10%
537
11th to 20thNight
12%110%27%42%8%
534
21st to endNight
14%29%28%38%8%
638
September1st to 10thNight
11%210%30%39%8%
720
11th to 20thNight
13%313%29%37%5%
720
21st to endNight
13%316%31%32%4
720
October1st to 10thNight
14%318%33%25%6%
720
11th to 20thNight
14%6%22%30%23%3
720
21st to endNight
14%8%23%32%21%2
792
November1st to 10thNight
11%9%21%36%19%3
740
11th to 20thNight
17%12%27%31%13%1
760
21st to endNight
14%11%29%29%14%1
760
December1st to 10thNight
20%14%26%30%9%2
760
11th to 20thNight
20%13%27%29%11%
760
21st to endNight
26%14%25%28%7%
836
Page generated at 2024-01-11 13:32:02. Version ac07

Copyright 2024 Attilla Danko


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