Towns County Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Towns County Park clear sky chart from 2005-11-05 to 2018-01-20.

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
49%
16021
21%
48491
15%
15979
56%
15979
24%
31299

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
30%
780
20%
2522
10%
776
42%
776
17%
1660
January16th to endNight
28%
788
21%
2557
12%
788
41%
788
18%
1685
February1st to 15thNight
32%
703
22%
2112
12%
701
43%
701
22%
1357
February16th to endNight
23%
631
21%
1893
9%
631
35%
631
17%
1302
March1st to 15thNight
31%
720
20%
2052
12%
720
39%
720
20%
1389
March16th to endNight
39%
768
18%
2112
11%
768
43%
768
23%
1431
April1st to 15thNight
40%
653
22%
1911
14%
653
49%
653
29%
1155
April16th to endNight
50%
540
22%
1671
17%
540
56%
540
27%
1040
May1st to 15thNight
52%
540
15%
1620
9%
540
56%
540
25%
1076
May16th to endNight
67%
561
17%
1683
12%
561
69%
561
28%
1073
June1st to 15thNight
68%
540
13%
1620
11%
540
69%
540
28%
1036
June16th to endNight
77%
540
16%
1620
14%
540
77%
540
32%
1003
July1st to 15thNight
71%
510
11%
1530
10%
510
71%
510
25%
1044
July16th to endNight
77%
564
14%
1595
12%
531
77%
531
27%
1041
August1st to 15thNight
71%
539
15%
1609
13%
536
71%
536
25%
1085
August16th to endNight
69%
573
17%
1886
18%
573
70%
573
25%
1236
September1st to 15thNight
62%
714
16%
1974
14%
714
63%
714
25%
1351
September16th to endNight
64%
717
24%
1980
21%
717
67%
717
31%
1244
October1st to 15thNight
56%
720
31%
2013
24%
720
62%
720
34%
1195
October16th to endNight
51%
768
33%
2304
25%
768
61%
768
32%
1342
November1st to 15thNight
54%
760
28%
2453
25%
760
61%
760
31%
1392
November16th to endNight
43%
780
26%
2535
20%
780
54%
780
25%
1530
December1st to 15thNight
39%
780
20%
2535
14%
780
48%
780
18%
1689
December16th to endNight
31%
832
18%
2704
13%
832
39%
832
15%
1943

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%6%25%5%35%5%5%7%36%
49036
Night
12%6%25%43445%7%42%
48689
TransparencyDay
44%7%11%17%15%3
48737
Night
40%6%12%19%16%4
48492
SeeingDay
16%7%18%21%20%15%
5813
Night
15%9%17%29%22%5%
16024

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%7%36%6%24335%39%
1746
16th to endDay
14%7%244245%5%6%41%
1768
February1st to 15thDay
16%8%45%5%33446%36%
1750
16th to endDay
19%6%26%423446%38%
1580
March1st to 15thDay
17%8%25%5%3445%6%37%
1908
16th to endDay
15%8%36%5%25%447%37%
2111
April1st to 15thDay
12%5%25%5%35%5%6%7%39%
2046
16th to endDay
14%5%25%5%35%446%41%
2289
May1st to 15thDay
14%6%36%6%36%5%5%6%36%
2331
16th to endDay
12%7%36%6%35%5%6%8%34%
2431
June1st to 15thDay
10%5%36%7%48%7%7%10%29%
2340
16th to endDay
6%426%7%47%7%8%9%35%
2340
July1st to 15thDay
12%6%37%8%47%6%8%9%23%
2340
16th to endDay
10%6%36%7%5%8%8%8%9%25%
2465
August1st to 15thDay
9%6%36%7%47%7%9%11%27%
2340
16th to endDay
14%7%37%7%46%7%6%8%25%
2307
September1st to 15thDay
12%8%36%7%5%6%5%6%7%29%
1980
16th to endDay
13%5%245%345%7%7%39%
1980
October1st to 15thDay
12%414423435%53%
1947
16th to endDay
12%6%2332323456%
1920
November1st to 15thDay
13%5%14214446%51%
1735
16th to endDay
14%6%34324446%45%
1755
December1st to 15thDay
18%7%36%43445%436%
1755
16th to endDay
22%9%35%423336%35%
1872
January1st to 15thNight
16%6%26%435%446%39%
2522
16th to endNight
16%8%36%5%24345%39%
2557
February1st to 15thNight
13%7%35%434346%42%
2103
16th to endNight
17%9%46%324435%37%
1893
March1st to 15thNight
14%8%35%424346%40%
2052
16th to endNight
13%7%46%433346%41%
2112
April1st to 15thNight
12%42442435%7%47%
1911
16th to endNight
9%5%34435%5%47%45%
1671
May1st to 15thNight
11%5%35%5%25%45%7%41%
1619
16th to endNight
6%4146%35%6%7%10%42%
1682
June1st to 15thNight
7%5%15%5%35%5%7%12%40%
1620
16th to endNight
44145%36%6%7%11%45%
1620
July1st to 15thNight
8%5%246%5%7%6%7%10%35%
1620
16th to endNight
6%4235%37%7%10%12%35%
1703
August1st to 15thNight
7%425%6%45%6%7%11%37%
1620
16th to endNight
10%5%25%445%5%6%11%37%
1886
September1st to 15thNight
8%6%25%7%35%6%7%9%36%
1974
16th to endNight
8%415%3345%7%9%45%
1980
October1st to 15thNight
11%423313347%53%
2013
16th to endNight
9%5%2443324455%
2304
November1st to 15thNight
11%43441335%6%51%
2453
16th to endNight
13%8%24323445%47%
2535
December1st to 15thNight
16%7%36%43445%6%37%
2535
16th to endNight
20%10%36%5%24446%30%
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
47%37%16%20%5%
1747
16th to endDay
41%5%7%19%19%6%
1768
February1st to 15thDay
46%5%7%17%20%3
1752
16th to endDay
45%5%8%18%18%3
1580
March1st to 15thDay
46%5%8%17%17%5%
1908
16th to endDay
46%6%11%17%14%2
2112
April1st to 15thDay
40%5%12%20%16%3
2046
16th to endDay
42%5%9%20%18%4
2289
May1st to 15thDay
45%7%11%18%13%2
2331
16th to endDay
46%8%13%17%11%2
2435
June1st to 15thDay
47%9%18%19%4
2340
16th to endDay
39%11%15%19%12%1
2340
July1st to 15thDay
52%10%16%14%5%
2201
16th to endDay
48%10%17%14%6%1
2310
August1st to 15thDay
46%11%15%17%7%1
2327
16th to endDay
52%10%14%14%7%
2307
September1st to 15thDay
50%9%10%14%11%2
1980
16th to endDay
42%5%14%15%19%3
1980
October1st to 15thDay
34%410%16%27%6%
1947
16th to endDay
34%25%19%26%11%
1920
November1st to 15thDay
34%46%16%29%9%
1735
16th to endDay
39%46%15%26%7%
1755
December1st to 15thDay
47%5%7%15%18%5%
1755
16th to endDay
51%39%14%15%4
1872
January1st to 15thNight
45%5%8%14%20%5%
2522
16th to endNight
47%36%16%20%5%
2557
February1st to 15thNight
41%49%18%20%5%
2112
16th to endNight
47%5%7%19%18%2
1893
March1st to 15thNight
45%5%9%17%16%6%
2052
16th to endNight
44%5%12%22%14%1
2112
April1st to 15thNight
35%412%25%18%4
1911
16th to endNight
37%5%10%22%18%4
1671
May1st to 15thNight
40%8%15%19%13%1
1620
16th to endNight
34%10%19%23%10%2
1684
June1st to 15thNight
34%11%24%22%6%
1620
16th to endNight
30%11%20%22%12%2
1620
July1st to 15thNight
40%11%21%19%6%1
1530
16th to endNight
33%13%24%18%8%1
1595
August1st to 15thNight
37%13%18%19%10%
1609
16th to endNight
40%8%20%19%9%1
1886
September1st to 15thNight
40%10%16%17%12%2
1974
16th to endNight
35%7%13%21%18%2
1980
October1st to 15thNight
31%5%11%20%25%5%
2013
16th to endNight
33%3420%27%10%
2304
November1st to 15thNight
33%36%19%25%10%
2453
16th to endNight
38%46%19%23%8%
2535
December1st to 15thNight
46%5%9%15%16%6%
2535
16th to endNight
54%47%14%14%3
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
25%17%36%16%5%
135
16th to endDay
25%23%32%11%7%
109
February1st to 15thDay
24%27%40%7%
90
16th to endDay
29%20%39%9%
81
March1st to 15thDay
25%12%28%25%7%1
198
16th to endDay
17%15%24%27%13%2
288
April1st to 15thDay
19%13%18%26%18%3
270
16th to endDay
14%7%18%28%21%9%
270
May1st to 15thDay
15%10%23%19%17%13%
288
16th to endDay
16%5%17%20%20%19%
331
June1st to 15thDay
12%29%24%27%24%
315
16th to endDay
10%215%21%22%27%
315
July1st to 15thDay
11%212%20%23%29%
305
16th to endDay
8%5%18%29%37%
326
August1st to 15thDay
15%28%23%19%30%
313
16th to endDay
15%29%15%30%27%
332
September1st to 15thDay
14%49%17%35%17%
315
16th to endDay
13%211%24%31%16%
314
October1st to 15thDay
17%6%15%26%25%8%
315
16th to endDay
16%8%17%26%25%5%
336
November1st to 15thDay
21%9%28%24%13%3
153
16th to endDay
14%14%28%23%14%3
135
December1st to 15thDay
28%16%31%18%31
135
16th to endDay
33%15%38%11%2
144
January1st to 15thNight
23%16%23%27%7%
780
16th to endNight
21%17%25%29%5%
788
February1st to 15thNight
21%17%24%31%4
704
16th to endNight
23%21%25%25%4
631
March1st to 15thNight
20%17%25%28%7%
720
16th to endNight
18%13%24%29%14%
768
April1st to 15thNight
15%14%26%26%14%1
653
16th to endNight
13%8%20%34%21%2
540
May1st to 15thNight
15%5%19%31%24%3
540
16th to endNight
10%210%34%33%8%
563
June1st to 15thNight
8%28%32%37%11%
540
16th to endNight
7%1428%42%15%
540
July1st to 15thNight
9%16%24%45%12%
510
16th to endNight
7%421%47%18%
564
August1st to 15thNight
10%15%23%46%12%
539
16th to endNight
12%1423%45%12%
573
September1st to 15thNight
12%28%27%37%10%
714
16th to endNight
12%211%35%33%4
717
October1st to 15thNight
16%6%16%28%26%6%
720
16th to endNight
12%11%18%29%24%3
768
November1st to 15thNight
13%9%17%33%21%4
760
16th to endNight
18%15%18%30%16%1
780
December1st to 15thNight
20%13%19%33%10%1
780
16th to endNight
25%12%22%31%6%
832
Page generated at 2018-01-21 12:19:22. Version ac04

Copyright 2018 A. Danko


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