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 2017-05-01.

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%
15472
20%
45647
16%
15431
63%
15431
29%
28871

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
69%
506
27%
1502
21%
506
74%
506
41%
851
May16th to endNight
74%
513
21%
1538
17%
513
76%
513
33%
956
June1st to 15thNight
70%
495
13%
1485
11%
495
71%
495
25%
1015
June16th to endNight
73%
495
8%
1485
7%
495
73%
495
21%
1055
July1st to 15thNight
71%
465
6%
1395
6%
465
71%
465
19%
1071
July16th to endNight
74%
522
6%
1469
5%
489
76%
489
19%
1094
August1st to 15thNight
78%
494
5%
1488
5%
491
78%
491
23%
1055
August16th to endNight
67%
649
9%
1874
9%
649
67%
649
20%
1348
September1st to 15thNight
65%
660
8%
1815
8%
660
65%
660
18%
1352
September16th to endNight
57%
657
13%
1815
12%
657
58%
657
19%
1352
October1st to 15thNight
68%
660
25%
1864
24%
660
70%
660
32%
1183
October16th to endNight
58%
704
28%
2112
24%
704
65%
704
32%
1264
November1st to 15thNight
57%
700
30%
2101
25%
700
64%
700
38%
1186
November16th to endNight
50%
720
28%
2241
22%
720
61%
720
33%
1321
December1st to 15thNight
50%
720
26%
2340
22%
720
58%
720
28%
1412
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%
46092
Night
7%425%5%35%5%6%9%44%
45856
TransparencyDay
43%9%12%15%13%6%
45793
Night
34%9%15%19%14%6%
45659
SeeingDay
9%314%21%24%27%
5217
Night
9%319%33%26%8%
15480

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%7%7%46%
2136
16th to endDay
8%437%8%5%7%6%7%7%33%
2223
June1st to 15thDay
11%6%47%8%5%7%7%6%9%24%
2145
16th to endDay
8%6%49%9%6%9%7%8%9%21%
2145
July1st to 15thDay
10%8%49%9%49%8%8%7%19%
2145
16th to endDay
6%6%49%10%6%10%7%8%8%19%
2283
August1st to 15thDay
6%6%38%10%6%9%8%8%11%20%
2128
16th to endDay
8%7%48%10%5%7%6%7%10%21%
1965
September1st to 15thDay
7%8%39%10%5%8%7%7%8%22%
1815
16th to endDay
9%7%39%9%6%8%6%8%8%22%
1815
October1st to 15thDay
8%426%6%5%7%6%7%7%37%
1766
16th to endDay
8%5%25%5%35%5%5%7%45%
1760
November1st to 15thDay
6%4245%25%45%7%51%
1757
16th to endDay
8%5%25%5%35%45%8%44%
1716
December1st to 15thDay
9%6%47%5%2446%7%41%
1620
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
42134245%6%10%53%
1502
16th to endNight
5%315%5%45%47%9%47%
1538
June1st to 15thNight
9%425%5%36%6%7%11%36%
1485
16th to endNight
6%4346%48%7%8%12%32%
1485
July1st to 15thNight
6%6%37%7%46%6%8%11%31%
1485
16th to endNight
4437%7%5%8%8%9%12%29%
1577
August1st to 15thNight
25%27%7%47%7%9%13%33%
1499
16th to endNight
6%6%37%6%35%6%9%11%32%
1874
September1st to 15thNight
7%5%36%7%47%7%8%13%29%
1815
16th to endNight
10%7%38%6%45%6%6%10%29%
1815
October1st to 15thNight
6%5%25%5%25%47%9%45%
1864
16th to endNight
8%5%2442445%6%50%
2112
November1st to 15thNight
6%42442345%7%54%
2101
16th to endNight
7%425%5%34447%49%
2241
December1st to 15thNight
9%5%35%43445%8%46%
2340
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
33%8%11%20%17%8%
2136
16th to endDay
45%8%11%18%13%1
2227
June1st to 15thDay
52%9%15%17%4
2145
16th to endDay
54%12%18%11%2
2145
July1st to 15thDay
59%13%17%8%
2006
16th to endDay
54%15%18%10%1
2128
August1st to 15thDay
52%15%25%6%
2115
16th to endDay
54%16%18%10%1
1965
September1st to 15thDay
55%14%16%10%3
1815
16th to endDay
53%11%14%11%6%1
1815
October1st to 15thDay
41%9%10%15%14%9%
1766
16th to endDay
36%6%8%14%21%12%
1760
November1st to 15thDay
31%48%22%22%10%
1757
16th to endDay
35%7%8%18%15%13%
1716
December1st to 15thDay
40%6%11%17%17%6%
1620
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%8%17%24%17%7%
1503
16th to endNight
30%11%16%23%17%1
1540
June1st to 15thNight
38%12%22%20%6%
1485
16th to endNight
40%15%23%17%3
1485
July1st to 15thNight
43%18%26%9%1
1395
16th to endNight
41%18%27%11%1
1469
August1st to 15thNight
36%18%35%9%
1488
16th to endNight
40%16%25%15%1
1874
September1st to 15thNight
43%17%22%13%3
1815
16th to endNight
47%12%17%15%5%2
1815
October1st to 15thNight
33%9%12%19%18%6%
1864
16th to endNight
33%5%8%15%25%9%
2112
November1st to 15thNight
29%411%22%22%9%
2101
16th to endNight
33%5%9%21%17%12%
2241
December1st to 15thNight
36%6%10%24%15%7%
2340
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
7%211%25%27%24%
229
16th to endDay
7%8%17%32%32%
267
June1st to 15thDay
12%15%12%24%43%
255
16th to endDay
6%19%22%58%
255
July1st to 15thDay
7%27%20%62%
245
16th to endDay
6%15%10%22%52%
270
August1st to 15thDay
13%15%9%18%52%
253
16th to endDay
10%6%8%18%55%
268
September1st to 15thDay
10%5%11%24%47%
255
16th to endDay
11%15%12%27%41%
254
October1st to 15thDay
9%39%28%34%14%
255
16th to endDay
10%120%31%27%8%
272
November1st to 15thDay
7%116%33%30%10%
265
16th to endDay
9%323%36%22%5%
186
December1st to 15thDay
6%438%33%16%
90
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%16%46%25%4
507
16th to endNight
6%19%40%36%6%
515
June1st to 15thNight
9%1428%40%15%
495
16th to endNight
8%316%43%28%
495
July1st to 15thNight
9%39%44%32%
465
16th to endNight
4211%47%33%
522
August1st to 15thNight
328%51%33%
494
16th to endNight
11%5%16%38%27%
649
September1st to 15thNight
10%5%23%38%20%
660
16th to endNight
15%7%25%40%10%
657
October1st to 15thNight
9%10%40%34%4
660
16th to endNight
11%218%35%28%2
704
November1st to 15thNight
8%224%39%21%3
700
16th to endNight
9%328%39%18%
720
December1st to 15thNight
9%5%28%35%19%1
720
16th to endNight
9%5%24%39%19%1
768
Page generated at 2017-05-02 08:43:33. Version ac04

Copyright 2017 A. Danko


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