Wright Brothers National Memorial
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wright Brothers National Memorial 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
49%
16261
19%
49109
13%
16224
55%
16224
26%
31451

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
33%
776
18%
2589
9%
776
44%
776
18%
1688
January16th to endNight
31%
832
22%
2704
12%
832
46%
832
22%
1701
February1st to 15thNight
32%
762
19%
2392
11%
761
45%
761
23%
1548
February16th to endNight
34%
683
24%
2049
13%
683
48%
683
28%
1242
March1st to 15thNight
41%
764
21%
2182
15%
764
50%
764
28%
1380
March16th to endNight
43%
768
19%
2049
13%
768
49%
768
28%
1362
April1st to 15thNight
45%
718
21%
1796
9%
718
51%
718
35%
1152
April16th to endNight
53%
720
19%
1800
9%
720
55%
720
33%
1200
May1st to 15thNight
53%
711
15%
1791
8%
711
55%
711
30%
1213
May16th to endNight
67%
399
18%
1522
20%
399
68%
399
25%
884
June1st to 15thNight
66%
360
15%
1440
17%
360
68%
360
22%
856
June16th to endNight
75%
360
15%
1440
18%
360
75%
360
24%
824
July1st to 15thNight
72%
356
12%
1376
14%
356
73%
356
23%
839
July16th to endNight
72%
564
13%
1595
11%
531
74%
531
28%
1025
August1st to 15thNight
65%
647
13%
1717
8%
644
66%
644
26%
1187
August16th to endNight
63%
764
16%
1910
11%
764
64%
764
29%
1322
September1st to 15thNight
65%
720
20%
1800
14%
720
67%
720
28%
1258
September16th to endNight
52%
717
17%
1931
14%
717
54%
717
22%
1398
October1st to 15thNight
54%
720
24%
2160
22%
720
60%
720
28%
1373
October16th to endNight
48%
768
32%
2304
25%
768
59%
768
32%
1344
November1st to 15thNight
44%
760
16%
2421
14%
760
50%
760
22%
1584
November16th to endNight
45%
780
23%
2535
18%
780
53%
780
25%
1525
December1st to 15thNight
37%
780
19%
2694
11%
780
49%
780
20%
1714
December16th to endNight
34%
832
21%
2912
12%
832
47%
832
20%
1832

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
12%5%2443445%8%43%
49504
Night
13%5%2442445%7%42%
49294
Cloud CoverDay
12%5%2443445%8%43%
49514
Night
13%5%25%42445%8%42%
49298
TransparencyDay
38%7%14%23%14%2
49207
Night
39%6%13%21%15%3
49109
SeeingDay
16%418%27%26%7%
6520
Night
16%5%20%30%21%4
16268

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%6%35%4345%46%41%
1676
16th to endDay
17%6%244235%5%5%42%
1872
February1st to 15thDay
15%6%25%6%2435%6%40%
1798
16th to endDay
12%5%245%24447%46%
1710
March1st to 15thDay
12%6%14313345%51%
2002
16th to endDay
15%5%25%433346%44%
2175
April1st to 15thDay
11%6%23323446%51%
2152
16th to endDay
10%424425%448%49%
2160
May1st to 15thDay
10%424435%5%6%8%44%
2158
16th to endDay
11%41442445%10%45%
2602
June1st to 15thDay
8%3244345%7%12%43%
2520
16th to endDay
5%3245%36%6%8%12%40%
2520
July1st to 15thDay
6%425%5%45%6%8%11%38%
2500
16th to endDay
8%425%5%36%6%8%10%39%
2465
August1st to 15thDay
10%5%245%35%5%6%11%38%
2218
16th to endDay
12%425%5%446%7%11%35%
2292
September1st to 15thDay
11%5%25%5%35%5%7%8%39%
2160
16th to endDay
18%6%36%5%35%45%6%33%
2025
October1st to 15thDay
16%6%25%5%33345%42%
1800
16th to endDay
12%42432435%5%50%
1920
November1st to 15thDay
19%41432435%6%42%
1767
16th to endDay
12%42332335%7%49%
1755
December1st to 15thDay
16%7%345%3435%6%40%
1593
16th to endDay
18%6%25%423436%41%
1664
January1st to 15thNight
13%5%45%6%34447%39%
2589
16th to endNight
16%7%34424346%43%
2704
February1st to 15thNight
18%6%34323346%42%
2391
16th to endNight
12%5%25%42345%7%47%
2049
March1st to 15thNight
13%423423446%47%
2170
16th to endNight
15%5%25%42346%6%42%
2049
April1st to 15thNight
10%5%25%42335%6%48%
1796
16th to endNight
14%5%2442435%6%46%
1800
May1st to 15thNight
11%5%245%345%7%9%40%
1791
16th to endNight
11%41433335%10%46%
1520
June1st to 15thNight
9%5%245%246%7%8%43%
1440
16th to endNight
6%323436%6%8%13%41%
1440
July1st to 15thNight
6%325%6%36%6%7%14%37%
1457
16th to endNight
8%415%435%5%8%12%39%
1703
August1st to 15thNight
9%6%25%6%45%6%6%10%35%
1728
16th to endNight
12%6%25%43447%10%36%
1910
September1st to 15thNight
15%4245%35%5%7%8%38%
1800
16th to endNight
18%7%36%5%3445%6%34%
1931
October1st to 15thNight
15%5%25%423347%45%
2160
16th to endNight
13%424312445%52%
2304
November1st to 15thNight
17%7%25%5%33447%39%
2421
16th to endNight
13%5%24323447%46%
2535
December1st to 15thNight
14%7%25%5%3445%7%39%
2694
16th to endNight
15%8%25%424446%42%
2912

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
13%6%26%4345%47%40%
1676
16th to endDay
17%6%25%4235%5%6%41%
1872
February1st to 15thDay
15%6%25%5%3345%6%40%
1798
16th to endDay
12%5%25%423446%46%
1710
March1st to 15thDay
12%6%23323346%51%
2013
16th to endDay
15%5%25%434347%44%
2174
April1st to 15thDay
11%6%2332335%6%50%
2152
16th to endDay
9%42442435%8%49%
2160
May1st to 15thDay
9%424335%6%6%8%44%
2158
16th to endDay
11%414425%45%10%45%
2602
June1st to 15thDay
7%314335%5%6%12%44%
2520
16th to endDay
5%4145%35%6%8%12%41%
2520
July1st to 15thDay
6%4245%35%6%8%12%40%
2500
16th to endDay
7%425%435%6%8%10%40%
2465
August1st to 15thDay
10%5%345%35%5%6%11%38%
2218
16th to endDay
11%5%245%35%5%7%10%36%
2292
September1st to 15thDay
10%5%245%36%5%6%8%40%
2160
16th to endDay
17%6%37%6%35%446%34%
2025
October1st to 15thDay
15%5%26%5%34345%43%
1800
16th to endDay
12%5%23323446%50%
1920
November1st to 15thDay
19%5%2343445%6%41%
1767
16th to endDay
12%424423347%49%
1755
December1st to 15thDay
15%7%245%2345%6%40%
1593
16th to endDay
18%6%25%5%34437%40%
1664
January1st to 15thNight
13%6%36%6%35%45%7%38%
2589
16th to endNight
16%7%24423345%43%
2704
February1st to 15thNight
17%6%34423346%41%
2384
16th to endNight
12%5%25%425%35%7%47%
2049
March1st to 15thNight
13%5%24424447%47%
2182
16th to endNight
15%5%26%43445%6%42%
2049
April1st to 15thNight
10%5%25%32435%7%48%
1796
16th to endNight
14%5%2442335%8%45%
1800
May1st to 15thNight
11%5%25%5%346%6%9%39%
1790
16th to endNight
10%435%4144411%46%
1520
June1st to 15thNight
9%5%23435%6%6%9%42%
1440
16th to endNight
5%3235%36%5%9%12%42%
1440
July1st to 15thNight
6%3346%35%5%8%14%37%
1457
16th to endNight
8%4246%35%6%9%12%38%
1703
August1st to 15thNight
10%426%6%36%5%7%9%35%
1728
16th to endNight
12%5%26%5%2447%9%37%
1910
September1st to 15thNight
14%5%245%35%6%7%8%37%
1800
16th to endNight
17%8%26%5%34446%34%
1931
October1st to 15thNight
15%5%25%434336%45%
2160
16th to endNight
13%5%24322346%51%
2304
November1st to 15thNight
17%6%25%5%2445%7%38%
2421
16th to endNight
13%5%24424446%45%
2535
December1st to 15thNight
14%7%35%5%3445%8%39%
2694
16th to endNight
15%7%25%424436%42%
2912

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
43%5%11%20%15%3
1677
16th to endDay
42%410%22%15%4
1872
February1st to 15thDay
43%39%21%17%3
1801
16th to endDay
38%5%11%25%15%3
1710
March1st to 15thDay
34%5%12%25%16%4
2013
16th to endDay
40%5%11%22%16%2
2175
April1st to 15thDay
33%413%25%19%3
2152
16th to endDay
33%5%13%24%17%5%
2160
May1st to 15thDay
35%9%17%22%13%1
2158
16th to endDay
34%9%15%27%12%
2606
June1st to 15thDay
31%9%18%28%11%
2520
16th to endDay
32%11%19%23%11%
2520
July1st to 15thDay
33%12%19%25%9%
2352
16th to endDay
34%11%18%23%11%
2310
August1st to 15thDay
38%9%20%19%11%
2205
16th to endDay
39%9%18%22%9%1
2292
September1st to 15thDay
38%9%14%20%14%2
2160
16th to endDay
49%6%10%18%13%
2025
October1st to 15thDay
43%47%23%19%1
1800
16th to endDay
34%5%7%25%24%3
1920
November1st to 15thDay
42%414%18%15%3
1767
16th to endDay
34%411%25%19%4
1755
December1st to 15thDay
44%413%24%11%1
1593
16th to endDay
44%411%22%13%3
1664
January1st to 15thNight
44%5%10%20%16%3
2589
16th to endNight
42%310%21%15%5%
2704
February1st to 15thNight
44%38%21%18%3
2392
16th to endNight
36%412%23%18%5%
2049
March1st to 15thNight
37%5%11%25%15%4
2182
16th to endNight
41%410%23%15%3
2049
April1st to 15thNight
35%414%20%20%4
1796
16th to endNight
37%6%11%21%17%5%
1800
May1st to 15thNight
38%8%16%22%12%1
1791
16th to endNight
32%10%16%25%12%1
1522
June1st to 15thNight
36%9%17%24%12%
1440
16th to endNight
31%11%22%22%11%1
1440
July1st to 15thNight
34%12%22%19%10%
1376
16th to endNight
33%12%21%23%9%
1595
August1st to 15thNight
41%8%19%19%9%
1717
16th to endNight
41%7%17%23%8%1
1910
September1st to 15thNight
41%8%15%18%13%2
1800
16th to endNight
49%7%10%18%13%
1931
October1st to 15thNight
39%5%9%23%20%2
2160
16th to endNight
34%37%25%24%4
2304
November1st to 15thNight
44%5%11%17%16%4
2421
16th to endNight
38%310%22%19%5%
2535
December1st to 15thNight
43%5%13%20%13%2
2694
16th to endNight
43%413%20%13%3
2912

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
17%15%28%29%9%
119
16th to endDay
20%9%29%23%15%1
144
February1st to 15thDay
22%13%31%28%4
224
16th to endDay
15%7%33%31%12%
291
March1st to 15thDay
17%11%30%28%10%1
312
16th to endDay
18%5%26%32%14%2
288
April1st to 15thDay
16%7%25%27%20%3
270
16th to endDay
12%220%35%24%5%
270
May1st to 15thDay
14%324%34%19%3
288
16th to endDay
15%112%25%30%15%
331
June1st to 15thDay
11%111%26%33%16%
315
16th to endDay
8%12%30%38%10%
315
July1st to 15thDay
7%5%26%44%14%
305
16th to endDay
9%6%20%49%13%
326
August1st to 15thDay
14%5%22%41%15%
313
16th to endDay
14%5%20%40%17%
332
September1st to 15thDay
15%110%26%32%13%
315
16th to endDay
23%211%28%28%6%
314
October1st to 15thDay
26%114%27%24%5%
315
16th to endDay
13%6%20%24%26%9%
336
November1st to 15thDay
20%6%22%28%16%5%
293
16th to endDay
14%11%23%25%23%1
285
December1st to 15thDay
27%9%27%19%13%2
123
16th to endDay
23%5%31%32%7%
96
January1st to 15thNight
15%15%29%26%11%
780
16th to endNight
20%11%30%31%6%
832
February1st to 15thNight
21%9%32%32%4
764
16th to endNight
16%9%34%28%9%
683
March1st to 15thNight
16%7%29%33%12%1
764
16th to endNight
18%426%34%13%1
768
April1st to 15thNight
13%430%34%16%
718
16th to endNight
16%419%37%18%2
720
May1st to 15thNight
13%319%41%19%3
711
16th to endNight
13%19%34%31%9%
400
June1st to 15thNight
11%210%34%35%6%
360
16th to endNight
6%18%37%41%5%
360
July1st to 15thNight
5%8%31%44%10%
356
16th to endNight
9%5%28%44%11%
564
August1st to 15thNight
13%6%29%40%9%
647
16th to endNight
16%5%22%40%13%
764
September1st to 15thNight
16%18%27%35%10%
720
16th to endNight
23%110%26%32%4
717
October1st to 15thNight
17%216%31%25%6%
720
16th to endNight
15%7%23%25%21%5%
768
November1st to 15thNight
21%421%30%16%4
760
16th to endNight
16%11%21%29%19%1
780
December1st to 15thNight
18%9%27%27%16%
780
16th to endNight
19%11%30%30%8%
832
Page generated at 2018-03-12 13:28:14. Version ac04

Copyright 2018 A. Danko


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