Wayah Bald
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wayah Bald clear sky chart from 2005-11-05 to 2017-12-20.

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
46%
15915
19%
48084
14%
15872
53%
15872
23%
31651

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
27%
720
19%
2327
11%
716
40%
716
17%
1547
January16th to endNight
23%
768
20%
2496
9%
768
37%
768
17%
1657
February1st to 15thNight
27%
704
20%
2124
9%
701
40%
701
22%
1371
February16th to endNight
21%
631
20%
1893
9%
631
32%
631
16%
1319
March1st to 15thNight
28%
720
20%
2046
10%
720
37%
720
19%
1397
March16th to endNight
33%
768
15%
2112
9%
768
37%
768
21%
1448
April1st to 15thNight
36%
664
21%
1922
11%
664
46%
664
26%
1198
April16th to endNight
45%
540
22%
1659
14%
540
54%
540
26%
1035
May1st to 15thNight
46%
540
14%
1620
7%
540
52%
540
22%
1097
May16th to endNight
61%
561
16%
1683
11%
561
64%
561
24%
1123
June1st to 15thNight
65%
540
12%
1620
9%
540
67%
540
25%
1093
June16th to endNight
72%
540
15%
1620
13%
540
73%
540
31%
1001
July1st to 15thNight
68%
510
9%
1530
8%
510
69%
510
22%
1082
July16th to endNight
73%
564
12%
1595
11%
531
74%
531
23%
1101
August1st to 15thNight
65%
539
14%
1609
13%
536
65%
536
20%
1145
August16th to endNight
66%
573
17%
1868
17%
573
67%
573
21%
1270
September1st to 15thNight
60%
720
14%
1980
13%
720
61%
720
22%
1399
September16th to endNight
61%
717
21%
1980
19%
717
62%
717
28%
1299
October1st to 15thNight
53%
720
29%
2022
23%
720
59%
720
32%
1239
October16th to endNight
49%
768
31%
2304
24%
768
60%
768
32%
1341
November1st to 15thNight
50%
760
26%
2445
23%
760
57%
760
29%
1435
November16th to endNight
46%
780
25%
2535
20%
780
55%
780
25%
1542
December1st to 15thNight
36%
780
20%
2535
14%
780
45%
780
17%
1697
December16th to endNight
32%
788
18%
2559
12%
788
40%
788
15%
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
13%6%36%6%35%5%5%7%35%
48757
Night
10%6%36%5%35%5%5%7%40%
48282
TransparencyDay
46%8%10%16%14%3
48458
Night
40%8%12%18%15%4
48085
SeeingDay
15%9%20%21%18%13%
5731
Night
14%10%20%27%22%5%
15917

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
13%8%5%6%5%35%34439%
1611
16th to endDay
13%6%35%434445%44%
1728
February1st to 15thDay
12%8%27%6%35%446%38%
1736
16th to endDay
13%7%38%42345%7%39%
1580
March1st to 15thDay
14%7%36%5%2445%7%37%
1914
16th to endDay
15%8%45%5%3445%5%35%
2111
April1st to 15thDay
11%6%26%5%35%6%7%6%38%
2037
16th to endDay
14%6%36%5%34446%41%
2300
May1st to 15thDay
14%7%37%7%45%446%34%
2331
16th to endDay
13%7%37%6%45%5%6%8%30%
2431
June1st to 15thDay
10%5%38%8%5%7%7%7%8%26%
2340
16th to endDay
7%5%27%8%47%7%8%8%31%
2340
July1st to 15thDay
12%7%48%9%5%7%7%7%9%19%
2340
16th to endDay
11%6%38%8%5%8%8%7%8%22%
2465
August1st to 15thDay
10%7%47%9%5%8%7%6%10%22%
2340
16th to endDay
16%7%39%8%5%6%5%6%7%21%
2320
September1st to 15thDay
15%7%39%8%45%5%5%6%26%
1980
16th to endDay
17%6%25%6%345%5%7%34%
1980
October1st to 15thDay
13%5%23323445%49%
1938
16th to endDay
11%6%2432332455%
1920
November1st to 15thDay
12%434423435%51%
1741
16th to endDay
13%7%24424445%45%
1755
December1st to 15thDay
14%7%37%5%245%45%37%
1755
16th to endDay
17%9%36%5%33345%36%
1764
January1st to 15thNight
12%7%36%6%45%45%5%38%
2327
16th to endNight
11%7%47%7%34445%39%
2496
February1st to 15thNight
10%6%35%5%35%45%6%42%
2115
16th to endNight
11%6%5%8%6%35%445%36%
1893
March1st to 15thNight
11%8%47%5%35%446%38%
2046
16th to endNight
11%7%46%5%35%45%6%39%
2112
April1st to 15thNight
10%5%245%2446%6%46%
1922
16th to endNight
10%5%35%42435%7%45%
1659
May1st to 15thNight
13%5%35%6%3446%8%38%
1619
16th to endNight
7%5%25%6%45%6%7%8%40%
1682
June1st to 15thNight
7%335%5%36%6%9%11%36%
1620
16th to endNight
5%3245%36%5%8%12%43%
1620
July1st to 15thNight
8%5%25%7%47%7%7%11%32%
1620
16th to endNight
7%425%5%36%8%7%13%33%
1703
August1st to 15thNight
10%436%7%46%5%7%9%34%
1620
16th to endNight
10%5%36%5%35%6%9%10%33%
1868
September1st to 15thNight
9%5%37%6%46%7%7%8%32%
1980
16th to endNight
13%5%245%3445%8%42%
1980
October1st to 15thNight
11%5%24423436%51%
2022
16th to endNight
8%5%25%42333455%
2304
November1st to 15thNight
10%5%24433336%50%
2445
16th to endNight
11%6%245%34445%46%
2535
December1st to 15thNight
13%7%37%5%345%5%6%37%
2535
16th to endNight
14%10%47%6%35%45%6%31%
2559

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
46%5%8%15%18%5%
1612
16th to endDay
40%5%9%19%18%6%
1728
February1st to 15thDay
45%5%7%18%19%3
1738
16th to endDay
43%5%11%17%18%3
1580
March1st to 15thDay
45%5%9%17%17%5%
1914
16th to endDay
48%6%11%16%13%2
2112
April1st to 15thDay
40%7%12%20%16%3
2037
16th to endDay
43%6%9%20%17%3
2300
May1st to 15thDay
48%8%11%17%11%2
2331
16th to endDay
48%10%13%15%10%1
2435
June1st to 15thDay
49%12%15%17%4
2340
16th to endDay
44%12%14%16%11%1
2340
July1st to 15thDay
55%13%13%12%4
2201
16th to endDay
51%13%14%12%6%1
2310
August1st to 15thDay
51%13%12%14%6%1
2327
16th to endDay
57%10%12%12%6%
2320
September1st to 15thDay
54%8%9%13%10%3
1980
16th to endDay
45%7%12%13%18%2
1980
October1st to 15thDay
35%6%9%17%25%6%
1938
16th to endDay
33%36%20%25%11%
1920
November1st to 15thDay
34%5%6%15%28%9%
1741
16th to endDay
38%5%7%15%26%7%
1755
December1st to 15thDay
46%7%6%14%17%6%
1755
16th to endDay
49%5%9%14%16%5%
1764
January1st to 15thNight
45%6%9%14%18%6%
2327
16th to endNight
46%5%7%15%19%5%
2496
February1st to 15thNight
41%5%11%17%19%4
2124
16th to endNight
47%6%8%18%16%2
1893
March1st to 15thNight
44%7%10%16%16%5%
2046
16th to endNight
42%7%13%19%13%1
2112
April1st to 15thNight
35%6%12%24%17%3
1922
16th to endNight
38%5%12%22%17%3
1659
May1st to 15thNight
41%9%15%20%11%1
1620
16th to endNight
37%12%16%22%9%1
1684
June1st to 15thNight
36%13%23%20%5%
1620
16th to endNight
30%12%21%22%11%1
1620
July1st to 15thNight
40%14%20%18%5%
1530
16th to endNight
36%16%22%16%6%1
1595
August1st to 15thNight
41%14%14%18%10%
1609
16th to endNight
41%12%17%19%7%1
1868
September1st to 15thNight
43%11%16%15%10%2
1980
16th to endNight
38%8%14%17%18%2
1980
October1st to 15thNight
33%5%10%21%24%3
2022
16th to endNight
32%46%19%26%9%
2304
November1st to 15thNight
34%5%7%17%24%9%
2445
16th to endNight
38%5%7%18%22%8%
2535
December1st to 15thNight
45%7%9%14%16%6%
2535
16th to endNight
51%6%8%13%14%4
2559

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%20%40%10%31
90
16th to endDay
16%43%31%44
96
February1st to 15thDay
20%35%40%4
90
16th to endDay
28%29%33%7%1
81
March1st to 15thDay
24%12%29%21%11%
204
16th to endDay
18%15%28%21%12%2
288
April1st to 15thDay
17%15%24%24%14%3
270
16th to endDay
17%9%22%23%18%8%
270
May1st to 15thDay
12%21%23%16%14%11%
288
16th to endDay
15%8%18%22%16%18%
331
June1st to 15thDay
10%315%25%23%22%
315
16th to endDay
8%424%18%19%25%
315
July1st to 15thDay
9%419%21%20%23%
305
16th to endDay
7%9%22%27%32%
326
August1st to 15thDay
15%113%23%22%23%
313
16th to endDay
15%112%18%24%26%
332
September1st to 15thDay
14%5%12%16%32%18%
315
16th to endDay
16%211%25%28%14%
314
October1st to 15thDay
17%6%15%26%23%10%
315
16th to endDay
13%11%18%26%22%6%
336
November1st to 15thDay
17%9%29%28%11%3
159
16th to endDay
13%15%34%21%13%2
135
December1st to 15thDay
22%25%31%15%4
135
16th to endDay
22%22%41%11%2
108
January1st to 15thNight
21%18%27%24%7%
720
16th to endNight
18%18%33%26%3
768
February1st to 15thNight
19%17%31%28%3
704
16th to endNight
21%23%28%22%3
631
March1st to 15thNight
16%21%28%26%6%
720
16th to endNight
16%14%27%27%12%1
768
April1st to 15thNight
16%17%26%26%12%1
664
16th to endNight
13%9%22%32%19%2
540
May1st to 15thNight
14%7%23%27%23%3
540
16th to endNight
9%315%30%31%9%
563
June1st to 15thNight
7%112%30%37%10%
540
16th to endNight
5%11%26%43%11%
540
July1st to 15thNight
8%17%24%47%10%
510
16th to endNight
7%7%19%46%17%
564
August1st to 15thNight
11%7%24%42%12%
539
16th to endNight
11%16%20%46%13%
573
September1st to 15thNight
11%210%23%40%11%
720
16th to endNight
15%211%28%35%5%
717
October1st to 15thNight
14%8%18%23%28%7%
720
16th to endNight
11%12%20%30%20%4
768
November1st to 15thNight
13%9%18%30%22%5%
760
16th to endNight
14%13%18%34%17%1
780
December1st to 15thNight
18%13%22%32%11%1
780
16th to endNight
20%14%27%30%7%
788
Page generated at 2017-12-21 07:04:51. Version ac04

Copyright 2017 A. Danko


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