Green Swamp Wildlife Management Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Green Swamp Wildlife Management Area clear sky chart from 2005-11-05 to 2017-12-04.

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
58%
16223
20%
47866
16%
16182
63%
16182
29%
30309

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
45%
718
19%
2327
15%
716
52%
716
24%
1462
January16th to endNight
44%
768
23%
2427
18%
768
51%
768
27%
1500
February1st to 15thNight
45%
701
25%
2103
17%
698
54%
698
34%
1255
February16th to endNight
41%
631
24%
1845
13%
631
52%
631
32%
1111
March1st to 15thNight
47%
720
30%
1980
16%
720
58%
720
40%
1133
March16th to endNight
52%
768
26%
2112
19%
768
58%
768
40%
1208
April1st to 15thNight
57%
718
23%
1976
17%
718
62%
718
42%
1115
April16th to endNight
59%
720
27%
1857
17%
720
65%
720
44%
1086
May1st to 15thNight
70%
548
25%
1628
20%
548
74%
548
41%
918
May16th to endNight
74%
561
23%
1682
18%
561
76%
561
34%
1029
June1st to 15thNight
68%
540
12%
1620
10%
540
68%
540
23%
1136
June16th to endNight
71%
540
8%
1620
7%
540
72%
540
21%
1168
July1st to 15thNight
72%
510
6%
1530
5%
510
72%
510
19%
1169
July16th to endNight
74%
564
5%
1595
5%
531
75%
531
18%
1197
August1st to 15thNight
78%
539
5%
1625
5%
536
78%
536
22%
1165
August16th to endNight
67%
708
9%
2045
9%
708
67%
708
19%
1468
September1st to 15thNight
65%
720
8%
1980
7%
720
65%
720
17%
1488
September16th to endNight
60%
717
15%
1980
14%
717
61%
717
20%
1442
October1st to 15thNight
67%
720
24%
2034
24%
720
69%
720
32%
1295
October16th to endNight
58%
768
30%
2304
26%
768
65%
768
34%
1363
November1st to 15thNight
59%
760
29%
2281
25%
760
66%
760
39%
1261
November16th to endNight
51%
780
30%
2428
24%
780
62%
780
34%
1418
December1st to 15thNight
51%
736
25%
2391
22%
736
58%
736
29%
1436
December16th to endNight
52%
768
23%
2496
22%
768
57%
768
29%
1486

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
8%5%36%7%46%5%6%8%36%
48607
Night
7%425%5%35%5%6%9%44%
48075
TransparencyDay
43%9%13%15%13%5%
48308
Night
34%9%15%19%14%6%
47878
SeeingDay
9%213%22%24%26%
6067
Night
9%318%33%26%8%
16231

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
11%6%24435%45%9%40%
1611
16th to endDay
10%5%35%5%2435%7%45%
1794
February1st to 15thDay
12%6%3443445%7%44%
1750
16th to endDay
9%5%25%5%24347%48%
1627
March1st to 15thDay
6%3145%45%45%7%51%
1980
16th to endDay
8%5%35%6%3445%5%48%
2111
April1st to 15thDay
6%415%6%36%46%7%45%
1972
16th to endDay
5%4245%46%5%6%8%45%
2100
May1st to 15thDay
5%425%6%35%5%6%7%47%
2329
16th to endDay
7%437%8%5%7%6%7%7%35%
2431
June1st to 15thDay
12%7%48%8%5%7%7%6%9%23%
2340
16th to endDay
7%6%49%9%6%9%7%8%9%21%
2340
July1st to 15thDay
9%7%48%9%5%9%8%8%8%20%
2340
16th to endDay
6%6%49%10%6%9%7%8%8%19%
2465
August1st to 15thDay
6%6%38%9%6%9%8%8%11%21%
2321
16th to endDay
9%7%48%10%5%7%6%7%10%21%
2145
September1st to 15thDay
8%7%39%10%5%9%7%7%9%21%
1980
16th to endDay
9%7%39%8%6%8%6%8%8%23%
1980
October1st to 15thDay
8%5%27%7%5%7%6%7%7%36%
1926
16th to endDay
8%5%25%435%5%5%7%46%
1920
November1st to 15thDay
5%4245%35%45%7%52%
1907
16th to endDay
8%5%25%5%35%45%8%45%
1859
December1st to 15thDay
8%6%37%5%2446%7%42%
1651
16th to endDay
7%5%25%5%35%5%6%8%44%
1728
January1st to 15thNight
9%6%36%5%3445%8%41%
2327
16th to endNight
12%5%34425%5%5%7%43%
2427
February1st to 15thNight
10%6%2431335%6%50%
2103
16th to endNight
8%5%26%423448%48%
1845
March1st to 15thNight
6%325%32335%7%55%
1980
16th to endNight
5%41442445%7%54%
2112
April1st to 15thNight
6%21432336%11%53%
1976
16th to endNight
7%313324448%55%
1857
May1st to 15thNight
4213435%5%5%10%54%
1628
16th to endNight
4215%5%35%47%9%48%
1682
June1st to 15thNight
11%425%6%36%6%7%10%34%
1620
16th to endNight
6%5%35%6%48%7%8%12%30%
1620
July1st to 15thNight
6%5%37%7%46%6%8%11%30%
1620
16th to endNight
4436%7%6%8%8%9%12%28%
1703
August1st to 15thNight
25%27%7%47%7%9%13%32%
1636
16th to endNight
7%6%26%6%35%7%9%11%32%
2045
September1st to 15thNight
7%5%36%7%47%7%8%13%28%
1980
16th to endNight
9%7%38%6%45%6%6%10%31%
1980
October1st to 15thNight
6%5%25%5%25%5%6%9%44%
2034
16th to endNight
8%5%2442445%6%50%
2304
November1st to 15thNight
5%42342345%7%55%
2281
16th to endNight
7%425%5%34447%50%
2428
December1st to 15thNight
9%5%35%43445%8%46%
2391
16th to endNight
7%436%5%25%46%8%44%
2496

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
39%5%9%19%17%6%
1612
16th to endDay
37%5%7%15%24%9%
1794
February1st to 15thDay
38%5%8%12%20%14%
1752
16th to endDay
36%410%15%21%11%
1627
March1st to 15thDay
30%6%10%22%21%8%
1980
16th to endDay
35%410%19%19%9%
2112
April1st to 15thDay
34%6%11%18%20%8%
1972
16th to endDay
34%6%10%17%22%8%
2100
May1st to 15thDay
32%8%11%20%18%8%
2329
16th to endDay
44%8%11%18%14%2
2435
June1st to 15thDay
55%9%14%16%4
2340
16th to endDay
54%12%18%11%2
2340
July1st to 15thDay
57%13%19%8%
2201
16th to endDay
55%15%18%9%1
2310
August1st to 15thDay
51%16%25%6%
2308
16th to endDay
54%16%17%10%1
2145
September1st to 15thDay
55%15%16%10%2
1980
16th to endDay
52%11%14%12%6%1
1980
October1st to 15thDay
42%9%10%15%13%8%
1926
16th to endDay
36%6%8%14%20%13%
1920
November1st to 15thDay
30%5%9%23%21%10%
1907
16th to endDay
35%7%8%19%16%12%
1859
December1st to 15thDay
40%6%11%18%16%6%
1651
16th to endDay
35%6%11%20%17%8%
1728
January1st to 15thNight
41%5%11%19%15%6%
2327
16th to endNight
37%6%10%17%18%9%
2427
February1st to 15thNight
33%48%17%21%14%
2112
16th to endNight
34%5%13%16%23%6%
1845
March1st to 15thNight
28%411%27%20%7%
1980
16th to endNight
27%5%13%25%19%8%
2112
April1st to 15thNight
25%6%16%24%20%6%
1976
16th to endNight
25%6%15%23%21%7%
1857
May1st to 15thNight
25%7%16%23%18%8%
1629
16th to endNight
29%10%16%23%17%2
1684
June1st to 15thNight
41%12%20%19%5%
1620
16th to endNight
41%15%22%16%3
1620
July1st to 15thNight
42%18%26%10%1
1530
16th to endNight
42%18%27%10%1
1595
August1st to 15thNight
37%18%33%9%
1625
16th to endNight
40%17%25%15%1
2045
September1st to 15thNight
44%17%21%12%3
1980
16th to endNight
45%12%17%17%5%2
1980
October1st to 15thNight
33%10%12%20%17%6%
2034
16th to endNight
33%5%8%16%25%10%
2304
November1st to 15thNight
28%411%23%23%8%
2281
16th to endNight
32%5%9%21%19%12%
2428
December1st to 15thNight
35%6%11%24%15%6%
2391
16th to endNight
35%6%13%21%15%8%
2496

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
15%12%34%20%15%2
90
16th to endDay
11%16%33%21%15%1
96
February1st to 15thDay
12%16%20%24%20%6%
90
16th to endDay
13%6%34%30%14%
128
March1st to 15thDay
7%7%28%33%19%2
270
16th to endDay
11%5%23%31%22%5%
288
April1st to 15thDay
7%6%22%28%27%8%
270
16th to endDay
5%214%28%33%15%
270
May1st to 15thDay
6%214%27%27%21%
288
16th to endDay
6%10%18%32%30%
331
June1st to 15thDay
17%16%11%23%39%
315
16th to endDay
7%210%22%56%
315
July1st to 15thDay
6%17%20%63%
305
16th to endDay
8%6%11%22%50%
326
August1st to 15thDay
11%48%19%54%
313
16th to endDay
12%7%9%18%51%
332
September1st to 15thDay
10%7%12%25%42%
315
16th to endDay
10%5%14%31%38%
314
October1st to 15thDay
9%310%29%33%13%
315
16th to endDay
10%321%33%23%7%
336
November1st to 15thDay
6%115%37%30%9%
325
16th to endDay
10%420%37%23%4
239
December1st to 15thDay
6%435%31%20%4
100
16th to endDay
7%215%44%26%4
96
January1st to 15thNight
12%7%27%37%14%
720
16th to endNight
13%7%30%35%13%
768
February1st to 15thNight
14%5%31%35%12%
704
16th to endNight
9%6%34%39%9%
631
March1st to 15thNight
6%7%34%38%12%
720
16th to endNight
7%428%42%14%1
768
April1st to 15thNight
6%5%25%44%17%
718
16th to endNight
7%323%44%20%
720
May1st to 15thNight
5%116%46%25%4
549
16th to endNight
5%19%39%36%6%
563
June1st to 15thNight
11%15%27%39%15%
540
16th to endNight
8%315%43%28%
540
July1st to 15thNight
8%28%44%33%
510
16th to endNight
4211%45%34%
564
August1st to 15thNight
328%50%34%
539
16th to endNight
12%5%16%38%26%
708
September1st to 15thNight
11%5%23%38%19%
720
16th to endNight
14%6%26%40%10%
717
October1st to 15thNight
9%11%40%34%4
720
16th to endNight
11%219%36%27%2
768
November1st to 15thNight
7%223%39%22%3
760
16th to endNight
9%327%39%18%
780
December1st to 15thNight
9%5%27%35%20%1
736
16th to endNight
9%5%24%39%19%1
768
Page generated at 2017-12-05 10:19:04. Version ac04

Copyright 2017 A. Danko


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