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 2005-11-05 to 2019-06-24.

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%
17975
23%
54026
15%
17932
56%
17932
27%
33571

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%
839
24%
2717
10%
836
43%
836
20%
1667
January16th to endNight
27%
896
25%
2905
13%
896
43%
896
22%
1786
February1st to 15thNight
32%
824
25%
2471
11%
820
47%
820
24%
1538
February16th to endNight
26%
735
24%
2205
9%
735
40%
735
23%
1389
March1st to 15thNight
30%
840
26%
2356
10%
840
43%
840
27%
1455
March16th to endNight
36%
896
21%
2464
10%
896
44%
896
29%
1532
April1st to 15thNight
40%
835
25%
2303
14%
835
49%
835
33%
1384
April16th to endNight
49%
624
27%
1918
17%
624
60%
624
34%
1088
May1st to 15thNight
56%
630
22%
1890
14%
630
63%
630
33%
1117
May16th to endNight
61%
657
20%
1970
15%
657
64%
657
29%
1245
June1st to 15thNight
64%
630
16%
1890
12%
630
66%
630
27%
1250
June16th to endNight
74%
609
16%
1828
13%
609
75%
609
32%
1136
July1st to 15thNight
69%
555
12%
1665
10%
555
70%
555
24%
1140
July16th to endNight
75%
612
13%
1739
12%
579
76%
579
27%
1141
August1st to 15thNight
70%
575
17%
1715
16%
572
70%
572
23%
1184
August16th to endNight
64%
653
15%
2068
15%
653
65%
653
22%
1391
September1st to 15thNight
63%
780
17%
2145
15%
780
64%
780
26%
1450
September16th to endNight
59%
777
22%
2145
17%
777
63%
777
30%
1383
October1st to 15thNight
55%
780
29%
2194
23%
780
62%
780
35%
1310
October16th to endNight
51%
832
34%
2496
25%
832
64%
832
37%
1378
November1st to 15thNight
51%
820
30%
2570
24%
820
61%
820
33%
1445
November16th to endNight
42%
840
28%
2730
18%
840
55%
840
30%
1540
December1st to 15thNight
37%
840
25%
2730
15%
840
51%
840
23%
1690
December16th to endNight
33%
896
21%
2912
14%
896
43%
896
19%
1932

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
12%5%25%5%35%5%5%7%42%
54785
Night
11%5%2442445%7%45%
54226
TransparencyDay
39%6%11%19%17%5%
54486
Night
36%6%11%19%19%7%
54029
SeeingDay
16%7%21%23%20%10%
7807
Night
14%8%22%29%21%3
17978

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
17%7%25%323445%44%
1881
16th to endDay
16%5%14314345%47%
2021
February1st to 15thDay
17%5%24415%346%42%
2050
16th to endDay
19%5%1432345%5%43%
1840
March1st to 15thDay
15%424324446%47%
2264
16th to endDay
13%5%24424446%45%
2463
April1st to 15thDay
12%425%5%3335%6%48%
2316
16th to endDay
8%3235%34447%50%
2644
May1st to 15thDay
9%424425%5%5%8%47%
2721
16th to endDay
10%5%25%5%36%5%6%8%40%
2847
June1st to 15thDay
10%426%6%46%6%7%10%35%
2730
16th to endDay
43246%46%6%8%13%40%
2639
July1st to 15thDay
6%5%36%7%47%7%8%10%31%
2535
16th to endDay
6%436%8%48%8%8%11%28%
2673
August1st to 15thDay
10%5%37%7%48%6%8%9%28%
2487
16th to endDay
12%6%36%8%47%6%6%8%30%
2467
September1st to 15thDay
11%5%26%6%36%5%6%8%36%
2145
16th to endDay
14%6%25%5%245%46%42%
2145
October1st to 15thDay
14%41431335%6%51%
2096
16th to endDay
11%31432233458%
2080
November1st to 15thDay
14%423323336%52%
1945
16th to endDay
12%424323345%52%
1890
December1st to 15thDay
17%6%2442445%5%42%
1890
16th to endDay
22%8%35%324345%37%
2016
January1st to 15thNight
14%7%25%31435%6%45%
2717
16th to endNight
16%6%34423345%47%
2905
February1st to 15thNight
16%5%24324446%46%
2463
16th to endNight
15%5%25%424446%45%
2205
March1st to 15thNight
11%424324446%48%
2356
16th to endNight
12%5%2442435%7%48%
2464
April1st to 15thNight
13%31332345%7%50%
2303
16th to endNight
7%414424448%52%
1918
May1st to 15thNight
7%424435%5%6%8%48%
1889
16th to endNight
8%3245%35%5%6%8%44%
1970
June1st to 15thNight
8%5%345%45%7%7%12%36%
1890
16th to endNight
43145%36%7%8%12%41%
1828
July1st to 15thNight
7%325%6%46%7%9%13%33%
1755
16th to endNight
43245%48%7%9%14%35%
1847
August1st to 15thNight
7%336%6%47%6%9%11%32%
1726
16th to endNight
9%5%26%6%45%5%9%9%35%
2068
September1st to 15thNight
9%425%7%45%5%6%11%36%
2145
16th to endNight
11%6%26%4235%5%6%45%
2145
October1st to 15thNight
12%42442334453%
2194
16th to endNight
9%22332434458%
2496
November1st to 15thNight
12%414322246%54%
2570
16th to endNight
11%423423345%53%
2730
December1st to 15thNight
16%5%24423446%45%
2730
16th to endNight
19%8%25%423345%39%
2912

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%47%17%25%4
1882
16th to endDay
38%36%19%23%8%
2021
February1st to 15thDay
42%38%20%19%5%
2052
16th to endDay
42%36%19%21%6%
1840
March1st to 15thDay
38%48%18%19%9%
2264
16th to endDay
38%5%10%21%18%5%
2464
April1st to 15thDay
36%310%22%20%6%
2316
16th to endDay
32%5%10%20%24%6%
2644
May1st to 15thDay
34%6%12%21%20%4
2721
16th to endDay
39%7%11%22%15%2
2851
June1st to 15thDay
41%9%15%20%11%1
2730
16th to endDay
31%11%19%21%13%2
2639
July1st to 15thDay
40%12%18%18%7%2
2396
16th to endDay
42%13%17%18%6%1
2518
August1st to 15thDay
47%11%14%16%8%1
2474
16th to endDay
49%10%14%16%9%
2467
September1st to 15thDay
43%8%12%16%15%2
2145
16th to endDay
40%7%10%19%17%4
2145
October1st to 15thDay
33%411%20%23%6%
2096
16th to endDay
30%3417%31%13%
2080
November1st to 15thDay
34%37%17%25%11%
1945
16th to endDay
34%46%19%26%8%
1890
December1st to 15thDay
43%49%16%18%7%
1890
16th to endDay
48%48%18%13%6%
2016
January1st to 15thNight
39%46%17%24%6%
2717
16th to endNight
40%3417%22%10%
2905
February1st to 15thNight
39%37%18%20%9%
2472
16th to endNight
39%47%17%22%8%
2205
March1st to 15thNight
35%49%17%21%10%
2356
16th to endNight
35%410%18%21%7%
2464
April1st to 15thNight
32%48%24%21%8%
2303
16th to endNight
29%5%10%22%20%11%
1918
May1st to 15thNight
31%6%14%22%19%5%
1890
16th to endNight
34%9%12%23%15%3
1972
June1st to 15thNight
37%10%17%21%12%
1890
16th to endNight
31%10%20%22%13%2
1828
July1st to 15thNight
37%13%19%18%7%3
1665
16th to endNight
32%14%23%19%7%2
1739
August1st to 15thNight
40%12%16%20%9%1
1715
16th to endNight
40%11%19%17%10%
2068
September1st to 15thNight
40%9%16%15%14%4
2145
16th to endNight
38%6%13%18%18%4
2145
October1st to 15thNight
33%410%19%24%8%
2194
16th to endNight
29%35%16%30%14%
2496
November1st to 15thNight
32%36%17%25%14%
2570
16th to endNight
32%37%16%26%12%
2730
December1st to 15thNight
39%48%19%20%7%
2730
16th to endNight
47%47%18%16%5%
2912

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
27%17%32%15%6%
180
16th to endDay
20%25%35%11%6%
192
February1st to 15thDay
30%17%36%12%2
180
16th to endDay
31%11%42%9%4
159
March1st to 15thDay
19%18%32%22%6%
344
16th to endDay
16%14%34%22%11%
416
April1st to 15thDay
18%14%27%21%14%3
390
16th to endDay
12%8%22%29%22%4
379
May1st to 15thDay
11%7%25%26%18%9%
408
16th to endDay
16%315%24%26%13%
459
June1st to 15thDay
14%114%24%23%20%
435
16th to endDay
6%13%27%26%24%
407
July1st to 15thDay
7%19%23%36%21%
365
16th to endDay
8%18%22%38%19%
390
August1st to 15thDay
15%10%23%31%19%
358
16th to endDay
14%110%26%29%18%
396
September1st to 15thDay
13%212%24%30%16%
375
16th to endDay
17%212%30%23%13%
374
October1st to 15thDay
18%318%27%20%10%
375
16th to endDay
12%10%23%26%21%6%
400
November1st to 15thDay
24%7%25%23%17%1
273
16th to endDay
11%14%28%30%11%2
180
December1st to 15thDay
29%13%35%15%6%
180
16th to endDay
32%15%29%17%4
192
January1st to 15thNight
20%16%31%22%7%
840
16th to endNight
20%17%30%26%4
896
February1st to 15thNight
20%13%28%30%5%
824
16th to endNight
18%16%34%27%3
735
March1st to 15thNight
15%16%33%29%5%
840
16th to endNight
16%12%29%27%12%
896
April1st to 15thNight
16%11%28%28%14%
835
16th to endNight
10%7%27%35%16%1
624
May1st to 15thNight
10%324%34%23%3
630
16th to endNight
10%116%32%31%6%
659
June1st to 15thNight
10%111%35%32%7%
630
16th to endNight
5%9%34%39%10%
609
July1st to 15thNight
8%18%27%40%13%
555
16th to endNight
5%8%27%49%8%
612
August1st to 15thNight
9%6%30%43%9%
575
16th to endNight
13%18%26%39%9%
653
September1st to 15thNight
11%110%27%40%8%
780
16th to endNight
14%215%31%31%4
777
October1st to 15thNight
15%320%27%25%7%
780
16th to endNight
11%7%24%31%22%2
832
November1st to 15thNight
14%7%21%33%20%2
820
16th to endNight
12%12%27%28%16%1
840
December1st to 15thNight
20%12%24%28%12%1
840
16th to endNight
23%12%27%28%7%
896
Page generated at 2019-06-24 20:41:28. Version ac04

Copyright 2019 A. Danko


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