Droop Mountain Battlefield State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Droop Mountain Battlefield State Park clear sky chart from 2005-11-05 to 2017-08-12.

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
39%
15619
16%
46808
10%
15581
46%
15581
21%
31272

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
18%
718
15%
2327
7%
716
27%
716
10%
1634
January16th to endNight
14%
768
14%
2496
5%
768
26%
768
13%
1701
February1st to 15thNight
18%
701
14%
2287
5%
701
29%
701
14%
1500
February16th to endNight
15%
631
14%
1894
5%
631
26%
631
13%
1347
March1st to 15thNight
25%
720
15%
1980
8%
720
32%
720
17%
1382
March16th to endNight
26%
768
14%
2112
8%
768
31%
768
17%
1530
April1st to 15thNight
30%
718
14%
1874
6%
718
36%
718
22%
1309
April16th to endNight
42%
620
18%
1700
9%
620
48%
620
24%
1126
May1st to 15thNight
39%
540
12%
1620
7%
540
44%
540
20%
1146
May16th to endNight
53%
561
13%
1684
10%
561
55%
561
24%
1128
June1st to 15thNight
62%
540
14%
1620
11%
540
66%
540
28%
1029
June16th to endNight
62%
540
16%
1620
11%
540
66%
540
30%
997
July1st to 15thNight
60%
510
10%
1530
9%
510
62%
510
24%
1031
July16th to endNight
73%
564
15%
1595
12%
531
75%
531
33%
969
August1st to 15thNight
67%
527
18%
1575
15%
524
68%
524
28%
1039
August16th to endNight
67%
604
18%
1654
14%
604
68%
604
32%
1070
September1st to 15thNight
63%
660
24%
1728
17%
660
65%
660
34%
1095
September16th to endNight
51%
657
19%
1815
16%
657
53%
657
25%
1228
October1st to 15thNight
49%
660
23%
1969
21%
660
55%
660
26%
1234
October16th to endNight
36%
704
23%
2112
14%
704
48%
704
23%
1326
November1st to 15thNight
42%
700
23%
2164
17%
700
51%
700
25%
1340
November16th to endNight
34%
720
18%
2406
13%
720
42%
720
18%
1546
December1st to 15thNight
24%
720
11%
2520
8%
720
30%
720
11%
1750
December16th to endNight
21%
768
16%
2526
7%
768
33%
768
12%
1815

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
14%6%36%6%35%5%5%7%33%
47142
Night
12%5%25%5%35%5%5%8%38%
47001
Cloud CoverDay
15%6%36%6%35%5%5%7%34%
47152
Night
13%5%25%5%35%5%5%7%39%
47005
TransparencyDay
48%7%12%18%11%1
46853
Night
42%7%15%20%12%2
46808
SeeingDay
20%12%20%21%15%8%
5393
Night
20%13%20%27%16%2
15626

By Month

Percentage Cloud Cover NE (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
13%7%5%8%7%45%7%5%6%28%
1611
16th to endDay
13%8%48%6%35%36%6%33%
1728
February1st to 15thDay
12%7%47%6%345%5%6%34%
1575
16th to endDay
13%8%49%5%35%5%46%32%
1575
March1st to 15thDay
14%6%37%5%2445%6%38%
1969
16th to endDay
16%9%46%5%34445%34%
2112
April1st to 15thDay
13%7%5%5%5%34447%40%
2074
16th to endDay
17%6%36%5%3445%7%35%
2270
May1st to 15thDay
20%7%36%7%36%45%7%28%
2331
16th to endDay
13%6%27%8%47%5%6%8%29%
2431
June1st to 15thDay
11%5%25%6%46%7%6%9%33%
2340
16th to endDay
10%5%37%7%47%5%7%7%32%
2340
July1st to 15thDay
14%6%36%7%46%7%6%8%27%
2340
16th to endDay
9%6%38%7%48%6%6%9%28%
2465
August1st to 15thDay
15%6%36%6%37%7%8%9%24%
2288
16th to endDay
11%6%38%7%5%6%6%7%8%29%
2184
September1st to 15thDay
14%5%26%5%345%6%7%37%
1900
16th to endDay
21%6%36%6%36%45%5%31%
1815
October1st to 15thDay
18%6%25%42335%6%39%
1661
16th to endDay
16%6%25%433345%43%
1760
November1st to 15thDay
11%5%245%2445%6%46%
1691
16th to endDay
15%6%36%6%345%45%38%
1550
December1st to 15thDay
16%8%35%5%36%45%7%32%
1440
16th to endDay
18%9%46%6%445%5%5%30%
1692
January1st to 15thNight
15%5%37%7%47%5%6%7%30%
2327
16th to endNight
12%7%37%7%35%5%5%8%32%
2496
February1st to 15thNight
11%6%36%6%345%5%8%37%
2285
16th to endNight
11%6%37%7%37%6%6%8%30%
1894
March1st to 15thNight
14%6%26%5%46%46%6%35%
1968
16th to endNight
14%7%26%6%35%5%6%7%34%
2112
April1st to 15thNight
12%5%35%6%35%45%9%37%
1874
16th to endNight
13%6%24435%5%5%9%40%
1700
May1st to 15thNight
18%7%35%5%345%47%36%
1620
16th to endNight
12%5%25%5%25%47%10%39%
1682
June1st to 15thNight
8%4235%25%5%7%11%44%
1620
16th to endNight
7%415%4245%7%9%46%
1620
July1st to 15thNight
10%5%25%5%35%6%6%8%40%
1620
16th to endNight
5%3145%35%5%7%12%44%
1703
August1st to 15thNight
12%3146%46%47%9%40%
1586
16th to endNight
10%5%2443446%7%44%
1654
September1st to 15thNight
12%41442446%7%48%
1728
16th to endNight
17%6%145%33437%40%
1815
October1st to 15thNight
13%5%25%443346%45%
1969
16th to endNight
12%5%345%345%46%43%
2112
November1st to 15thNight
11%6%2442445%7%44%
2164
16th to endNight
15%5%35%5%35%5%46%38%
2406
December1st to 15thNight
15%7%37%7%46%5%5%6%31%
2520
16th to endNight
16%8%35%7%45%6%5%6%31%
2526

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
14%8%5%7%8%445%5%6%29%
1611
16th to endDay
14%8%48%5%3445%5%34%
1728
February1st to 15thDay
12%8%47%6%35%45%6%35%
1575
16th to endDay
14%9%49%6%25%446%32%
1575
March1st to 15thDay
15%6%37%425%35%6%39%
1980
16th to endDay
17%9%35%5%34445%35%
2111
April1st to 15thDay
13%7%45%42445%6%41%
2074
16th to endDay
18%5%25%5%345%5%7%36%
2270
May1st to 15thDay
20%6%36%6%35%5%5%6%29%
2331
16th to endDay
13%6%27%6%5%6%5%5%8%31%
2431
June1st to 15thDay
13%425%6%46%6%6%9%34%
2340
16th to endDay
11%5%36%7%47%6%7%7%32%
2340
July1st to 15thDay
15%6%36%7%35%7%5%9%28%
2340
16th to endDay
9%6%46%7%47%7%7%9%29%
2465
August1st to 15thDay
16%6%26%6%47%7%7%9%25%
2288
16th to endDay
12%6%37%8%47%6%6%8%29%
2184
September1st to 15thDay
14%5%25%5%25%6%6%8%37%
1900
16th to endDay
21%6%36%5%35%45%5%32%
1815
October1st to 15thDay
19%5%25%5%23346%40%
1661
16th to endDay
17%7%25%5%23335%44%
1760
November1st to 15thDay
11%6%2442435%6%47%
1691
16th to endDay
15%7%36%5%35%45%5%38%
1550
December1st to 15thDay
17%8%35%5%35%46%6%33%
1440
16th to endDay
19%9%36%5%4446%5%30%
1692
January1st to 15thNight
15%5%38%6%36%5%6%7%30%
2327
16th to endNight
13%6%47%6%35%45%7%33%
2496
February1st to 15thNight
11%6%27%6%345%5%8%37%
2278
16th to endNight
11%6%37%8%36%6%6%7%31%
1894
March1st to 15thNight
14%5%36%5%36%6%5%6%36%
1980
16th to endNight
14%6%36%6%245%5%7%35%
2112
April1st to 15thNight
12%6%35%6%35%45%8%38%
1874
16th to endNight
13%6%24435%46%8%40%
1700
May1st to 15thNight
17%7%25%42445%7%36%
1619
16th to endNight
12%5%25%5%2446%9%40%
1682
June1st to 15thNight
8%324435%5%7%10%45%
1620
16th to endNight
8%415%4245%7%10%46%
1620
July1st to 15thNight
10%5%15%5%35%6%6%8%40%
1620
16th to endNight
5%324435%5%7%11%46%
1703
August1st to 15thNight
12%3135%36%5%6%8%41%
1586
16th to endNight
10%425%5%3346%8%44%
1654
September1st to 15thNight
13%31332446%7%49%
1728
16th to endNight
17%6%24433437%41%
1815
October1st to 15thNight
13%5%25%433445%46%
1969
16th to endNight
13%5%245%25%45%7%43%
2112
November1st to 15thNight
12%6%3442446%6%45%
2164
16th to endNight
16%5%35%435%5%47%39%
2406
December1st to 15thNight
16%6%36%7%46%5%5%6%31%
2520
16th to endNight
16%7%36%7%345%6%6%31%
2526

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
54%6%12%14%9%1
1612
16th to endDay
49%415%17%11%1
1728
February1st to 15thDay
49%5%12%19%11%1
1577
16th to endDay
52%6%11%18%9%
1575
March1st to 15thDay
45%5%13%22%10%2
1980
16th to endDay
51%5%11%19%10%1
2112
April1st to 15thDay
43%6%11%21%13%3
2074
16th to endDay
47%6%11%17%14%3
2270
May1st to 15thDay
53%8%11%16%8%1
2331
16th to endDay
49%9%13%17%7%1
2435
June1st to 15thDay
44%10%14%19%11%
2340
16th to endDay
46%9%14%15%12%1
2340
July1st to 15thDay
50%10%11%13%11%2
2201
16th to endDay
46%11%12%16%11%
2310
August1st to 15thDay
50%9%15%15%9%
2275
16th to endDay
49%9%13%18%7%1
2184
September1st to 15thDay
42%7%11%19%16%2
1900
16th to endDay
52%6%7%17%15%
1815
October1st to 15thDay
44%5%12%21%13%3
1661
16th to endDay
42%412%24%14%2
1760
November1st to 15thDay
37%412%19%20%5%
1691
16th to endDay
46%312%20%16%1
1550
December1st to 15thDay
48%6%13%16%11%2
1440
16th to endDay
53%412%18%8%1
1692
January1st to 15thNight
50%6%15%15%10%1
2327
16th to endNight
48%5%16%18%9%1
2496
February1st to 15thNight
43%6%15%21%11%1
2287
16th to endNight
48%7%15%18%8%
1894
March1st to 15thNight
46%6%14%21%9%1
1980
16th to endNight
46%9%13%18%10%1
2112
April1st to 15thNight
44%6%13%19%12%2
1874
16th to endNight
40%6%15%18%14%4
1700
May1st to 15thNight
47%8%16%15%11%
1620
16th to endNight
39%10%19%22%6%1
1684
June1st to 15thNight
32%12%18%23%12%
1620
16th to endNight
31%11%19%25%11%
1620
July1st to 15thNight
39%11%15%18%11%3
1530
16th to endNight
27%12%20%25%12%1
1595
August1st to 15thNight
37%9%16%21%12%
1575
16th to endNight
36%7%15%26%11%2
1654
September1st to 15thNight
32%8%15%19%21%2
1728
16th to endNight
42%6%10%23%16%
1815
October1st to 15thNight
39%412%25%14%3
1969
16th to endNight
39%412%24%16%2
2112
November1st to 15thNight
38%5%11%18%19%6%
2164
16th to endNight
44%413%19%15%2
2406
December1st to 15thNight
52%5%15%15%9%2
2520
16th to endNight
51%7%12%18%8%
2526

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
34%27%21%8%5%2
90
16th to endDay
43%21%20%11%2
96
February1st to 15thDay
30%41%23%5%
90
16th to endDay
27%26%27%16%2
111
March1st to 15thDay
29%18%24%20%7%
270
16th to endDay
23%21%25%20%7%1
288
April1st to 15thDay
18%22%21%23%12%1
270
16th to endDay
21%11%25%17%17%6%
270
May1st to 15thDay
26%16%23%13%13%5%
288
16th to endDay
19%10%19%21%18%11%
331
June1st to 15thDay
14%9%19%25%18%12%
315
16th to endDay
12%11%28%22%15%9%
315
July1st to 15thDay
18%5%29%21%14%11%
305
16th to endDay
10%216%31%20%18%
326
August1st to 15thDay
20%313%23%21%17%
297
16th to endDay
11%28%24%26%27%
268
September1st to 15thDay
12%410%24%29%18%
255
16th to endDay
24%7%15%21%22%9%
254
October1st to 15thDay
20%9%16%26%20%5%
255
16th to endDay
22%11%24%23%15%2
272
November1st to 15thDay
21%10%19%27%19%2
199
16th to endDay
32%23%20%19%5%
78
December1st to 15thDay
36%26%11%13%6%5%
60
16th to endDay
41%21%25%12%
90
January1st to 15thNight
30%23%23%16%5%
720
16th to endNight
27%23%30%17%1
768
February1st to 15thNight
28%21%28%19%1
704
16th to endNight
22%27%31%17%1
631
March1st to 15thNight
24%19%27%24%4
720
16th to endNight
21%19%26%23%8%
768
April1st to 15thNight
18%20%26%26%7%
718
16th to endNight
20%10%21%30%15%1
620
May1st to 15thNight
23%8%22%31%12%1
540
16th to endNight
15%5%16%29%29%3
563
June1st to 15thNight
8%415%34%32%3
540
16th to endNight
9%316%39%28%2
540
July1st to 15thNight
13%212%37%31%2
510
16th to endNight
5%38%32%40%8%
564
August1st to 15thNight
14%9%38%32%3
527
16th to endNight
12%17%31%38%6%
604
September1st to 15thNight
14%411%29%33%6%
660
16th to endNight
21%5%15%28%26%3
657
October1st to 15thNight
17%11%16%29%21%3
660
16th to endNight
19%17%22%25%14%1
704
November1st to 15thNight
17%14%20%30%15%1
700
16th to endNight
25%16%20%26%9%1
720
December1st to 15thNight
25%20%24%22%5%
720
16th to endNight
29%16%27%23%3
768
Page generated at 2017-08-13 14:16:36. Version ac04

Copyright 2017 A. Danko


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