Augusta
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Augusta clear sky chart from 2005-11-05 to 2018-03-11.

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
46%
16439
23%
49066
15%
16394
55%
16394
27%
29952

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
29%
780
24%
2522
11%
776
46%
776
23%
1504
January16th to endNight
30%
832
25%
2704
15%
832
44%
832
24%
1654
February1st to 15thNight
32%
764
24%
2343
11%
759
46%
759
24%
1444
February16th to endNight
29%
683
26%
2043
10%
683
45%
683
26%
1218
March1st to 15thNight
33%
764
27%
2101
13%
764
46%
764
30%
1264
March16th to endNight
35%
768
22%
2112
11%
768
44%
768
28%
1275
April1st to 15thNight
39%
718
25%
1973
13%
718
48%
718
31%
1171
April16th to endNight
44%
612
27%
1692
14%
612
54%
612
31%
1003
May1st to 15thNight
47%
539
21%
1620
11%
539
55%
539
28%
963
May16th to endNight
52%
561
20%
1682
12%
561
58%
561
24%
1040
June1st to 15thNight
58%
540
16%
1620
13%
540
59%
540
24%
1028
June16th to endNight
61%
540
14%
1620
11%
540
63%
540
27%
1002
July1st to 15thNight
62%
510
12%
1530
9%
510
64%
510
23%
1002
July16th to endNight
64%
564
12%
1595
10%
531
69%
531
24%
1064
August1st to 15thNight
64%
539
16%
1609
14%
536
65%
536
25%
1084
August16th to endNight
58%
648
15%
1872
12%
648
59%
648
22%
1287
September1st to 15thNight
64%
720
18%
1980
16%
720
65%
720
29%
1286
September16th to endNight
54%
717
20%
1980
14%
717
60%
717
24%
1324
October1st to 15thNight
54%
720
30%
2070
27%
720
61%
720
33%
1233
October16th to endNight
55%
768
37%
2304
29%
768
68%
768
39%
1225
November1st to 15thNight
50%
760
31%
2320
25%
760
59%
760
33%
1273
November16th to endNight
43%
780
29%
2535
19%
780
57%
780
29%
1412
December1st to 15thNight
39%
780
25%
2535
16%
780
52%
780
24%
1486
December16th to endNight
31%
832
23%
2704
14%
832
44%
832
20%
1710

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
11%5%245%345%5%7%43%
49554
Night
12%5%2443445%7%45%
49269
TransparencyDay
38%411%21%18%5%
49255
Night
37%411%19%19%7%
49072
SeeingDay
13%10%14%22%22%15%
6182
Night
12%16%16%28%21%3
16442

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
15%5%25%413446%45%
1746
16th to endDay
15%6%24423446%46%
1872
February1st to 15thDay
16%435%3145%5%6%43%
1842
16th to endDay
17%6%24324335%47%
1716
March1st to 15thDay
13%425%324446%49%
2096
16th to endDay
15%5%25%423436%47%
2111
April1st to 15thDay
9%42342435%7%49%
1975
16th to endDay
8%3144345%6%8%49%
2277
May1st to 15thDay
9%5%14425%46%8%45%
2331
16th to endDay
10%6%246%46%5%6%9%38%
2431
June1st to 15thDay
9%5%245%36%6%7%11%37%
2340
16th to endDay
5%3145%46%7%9%10%40%
2340
July1st to 15thDay
7%6%36%7%5%6%7%7%9%33%
2340
16th to endDay
6%426%7%5%7%8%8%12%30%
2465
August1st to 15thDay
8%5%26%7%46%8%8%10%30%
2340
16th to endDay
12%6%26%7%47%7%7%9%27%
2315
September1st to 15thDay
8%5%25%5%35%6%6%8%41%
1980
16th to endDay
15%7%346%2445%6%40%
1980
October1st to 15thDay
14%5%14322335%52%
1890
16th to endDay
10%31432333360%
1920
November1st to 15thDay
12%5%22323245%54%
1865
16th to endDay
13%424324336%51%
1755
December1st to 15thDay
18%6%1442335%6%43%
1755
16th to endDay
20%7%24423446%39%
1872
January1st to 15thNight
13%6%25%32335%6%46%
2522
16th to endNight
17%5%2432323447%
2704
February1st to 15thNight
16%6%13423346%45%
2338
16th to endNight
13%5%24434346%48%
2043
March1st to 15thNight
12%424424445%51%
2101
16th to endNight
12%42342446%6%47%
2112
April1st to 15thNight
11%413424446%52%
1973
16th to endNight
9%215%5%25%45%6%50%
1692
May1st to 15thNight
8%424435%5%6%9%44%
1619
16th to endNight
7%4245%46%6%8%7%42%
1682
June1st to 15thNight
10%5%25%5%45%6%5%11%35%
1620
16th to endNight
4325%445%7%10%12%38%
1620
July1st to 15thNight
7%425%6%46%6%8%11%33%
1620
16th to endNight
5%425%6%47%8%8%13%32%
1703
August1st to 15thNight
8%425%5%37%8%8%12%31%
1620
16th to endNight
11%6%26%6%45%5%5%11%33%
1872
September1st to 15thNight
8%425%5%35%6%6%10%39%
1980
16th to endNight
13%5%25%5%445%5%6%40%
1980
October1st to 15thNight
14%424313246%52%
2070
16th to endNight
8%314313335%59%
2304
November1st to 15thNight
11%314312246%57%
2320
16th to endNight
13%423314336%52%
2535
December1st to 15thNight
15%5%1442335%6%47%
2535
16th to endNight
19%6%24423346%41%
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
38%29%18%24%5%
1747
16th to endDay
38%26%19%24%8%
1872
February1st to 15thDay
39%36%20%22%6%
1844
16th to endDay
39%2422%23%6%
1716
March1st to 15thDay
36%27%21%19%12%
2096
16th to endDay
37%211%22%20%5%
2112
April1st to 15thDay
33%39%21%24%7%
1975
16th to endDay
30%49%24%24%7%
2277
May1st to 15thDay
35%313%24%19%3
2331
16th to endDay
40%414%25%12%2
2435
June1st to 15thDay
39%6%17%25%11%
2340
16th to endDay
31%7%18%26%12%2
2340
July1st to 15thDay
41%7%18%21%7%3
2201
16th to endDay
41%8%18%20%8%1
2310
August1st to 15thDay
44%8%15%21%9%1
2327
16th to endDay
48%7%16%17%9%
2315
September1st to 15thDay
38%6%14%17%17%4
1980
16th to endDay
45%49%17%17%5%
1980
October1st to 15thDay
34%27%21%24%9%
1890
16th to endDay
29%2319%31%14%
1920
November1st to 15thDay
32%17%20%25%12%
1865
16th to endDay
34%27%20%23%11%
1755
December1st to 15thDay
41%39%18%20%7%
1755
16th to endDay
46%27%20%16%6%
1872
January1st to 15thNight
38%37%17%25%8%
2522
16th to endNight
41%2317%23%11%
2704
February1st to 15thNight
40%16%19%20%11%
2347
16th to endNight
37%27%19%24%9%
2043
March1st to 15thNight
34%28%19%24%10%
2101
16th to endNight
34%311%21%20%8%
2112
April1st to 15thNight
32%38%22%23%9%
1973
16th to endNight
32%39%20%24%9%
1692
May1st to 15thNight
34%415%22%18%4
1620
16th to endNight
35%7%13%25%16%1
1684
June1st to 15thNight
40%5%16%26%11%
1620
16th to endNight
33%8%20%21%12%3
1620
July1st to 15thNight
39%9%22%18%7%3
1530
16th to endNight
37%11%22%19%7%1
1595
August1st to 15thNight
39%9%18%22%9%
1609
16th to endNight
44%6%19%19%8%
1872
September1st to 15thNight
37%7%16%18%14%5%
1980
16th to endNight
44%411%19%15%5%
1980
October1st to 15thNight
34%28%18%25%9%
2070
16th to endNight
27%25%20%29%15%
2304
November1st to 15thNight
30%26%18%26%15%
2320
16th to endNight
33%37%16%25%14%
2535
December1st to 15thNight
37%210%20%20%8%
2535
16th to endNight
44%18%20%16%6%
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
16%13%38%25%5%
135
16th to endDay
16%18%32%25%6%1
144
February1st to 15thDay
20%13%42%21%2
135
16th to endDay
19%11%35%22%9%1
126
March1st to 15thDay
12%16%30%27%11%
312
16th to endDay
14%16%26%27%13%1
288
April1st to 15thDay
12%20%19%18%21%7%
270
16th to endDay
8%14%14%26%27%9%
270
May1st to 15thDay
8%15%19%22%22%11%
288
16th to endDay
14%12%7%19%23%21%
331
June1st to 15thDay
11%11%416%26%28%
315
16th to endDay
7%9%5%24%22%30%
315
July1st to 15thDay
5%7%216%35%31%
305
16th to endDay
8%10%213%33%30%
326
August1st to 15thDay
13%7%215%35%25%
313
16th to endDay
13%6%316%23%35%
332
September1st to 15thDay
12%6%6%20%28%24%
315
16th to endDay
18%7%9%21%26%16%
314
October1st to 15thDay
19%5%12%28%22%11%
315
16th to endDay
9%8%17%25%27%10%
336
November1st to 15thDay
18%10%13%29%22%5%
283
16th to endDay
8%5%23%31%23%5%
135
December1st to 15thDay
26%5%28%27%12%
135
16th to endDay
28%9%30%20%8%2
144
January1st to 15thNight
15%21%28%27%7%
780
16th to endNight
15%20%28%30%5%
832
February1st to 15thNight
16%21%25%30%6%
764
16th to endNight
13%21%30%30%4
683
March1st to 15thNight
13%21%27%30%7%
764
16th to endNight
13%21%24%28%11%
768
April1st to 15thNight
12%20%23%27%15%
718
16th to endNight
9%19%17%32%19%
612
May1st to 15thNight
9%18%17%34%18%1
540
16th to endNight
7%18%9%26%31%5%
563
June1st to 15thNight
10%17%427%34%6%
540
16th to endNight
5%17%5%24%36%10%
540
July1st to 15thNight
8%13%224%41%9%
510
16th to endNight
6%17%222%43%7%
564
August1st to 15thNight
11%10%224%43%8%
539
16th to endNight
14%9%423%38%9%
648
September1st to 15thNight
9%8%5%24%44%6%
720
16th to endNight
16%9%9%28%31%5%
717
October1st to 15thNight
14%10%13%30%26%4
720
16th to endNight
9%10%19%31%25%3
768
November1st to 15thNight
12%15%16%32%19%3
760
16th to endNight
12%19%19%28%17%1
780
December1st to 15thNight
14%19%20%30%13%1
780
16th to endNight
19%19%24%28%7%
832
Page generated at 2018-03-12 13:28:06. Version ac04

Copyright 2018 A. Danko


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