Charlie Elliott WLC
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Charlie Elliott WLC clear sky chart from 2005-11-06 to 2024-01-15.

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
47%
23944
23%
74429
15%
23888
56%
23888
27%
45706

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 10thNight
24%
760
24%
2459
8%
757
42%
757
20%
1515
January11th to 20thNight
29%
739
26%
2399
12%
739
45%
739
21%
1498
January21st to endNight
24%
792
28%
2520
11%
792
43%
792
23%
1547
February1st to 10thNight
31%
720
25%
2160
12%
720
45%
720
25%
1370
February11th to 20thNight
26%
703
23%
2098
8%
699
40%
699
21%
1343
February21st to endNight
24%
592
24%
1776
10%
592
38%
592
23%
1144
March1st to 10thNight
33%
720
28%
2074
14%
720
44%
720
29%
1268
March11th to 20thNight
32%
720
22%
1980
9%
720
43%
720
26%
1271
March21st to endNight
35%
792
25%
2178
10%
792
46%
792
28%
1353
April1st to 10thNight
38%
720
25%
1980
14%
720
48%
720
33%
1183
April11th to 20thNight
44%
561
27%
1803
17%
561
55%
561
32%
1014
April21st to endNight
53%
540
31%
1632
20%
540
63%
540
36%
900
May1st to 10thNight
51%
540
25%
1620
13%
540
60%
540
35%
913
May11th to 20thNight
54%
531
17%
1592
11%
531
58%
531
28%
1009
May21st to endNight
62%
582
21%
1744
17%
582
64%
582
31%
1084
June1st to 10thNight
67%
540
16%
1620
14%
540
69%
540
28%
1051
June11th to 20thNight
71%
540
19%
1620
16%
540
73%
540
38%
939
June21st to endNight
72%
540
16%
1620
12%
540
73%
540
32%
979
July1st to 10thNight
68%
525
13%
1575
12%
525
69%
525
26%
1042
July11th to 20thNight
74%
522
11%
1566
9%
522
75%
522
26%
1031
July21st to endNight
74%
591
16%
1672
14%
558
75%
558
29%
1077
August1st to 10thNight
69%
537
14%
1600
14%
534
70%
534
24%
1079
August11th to 20thNight
68%
534
18%
1700
19%
534
68%
534
23%
1133
August21st to endNight
60%
603
17%
1989
17%
603
61%
603
21%
1344
September1st to 10thNight
65%
720
19%
1980
17%
720
66%
720
31%
1296
September11th to 20thNight
61%
720
22%
1980
19%
720
64%
720
31%
1284
September21st to endNight
61%
720
27%
1980
20%
720
65%
720
33%
1245
October1st to 10thNight
55%
720
28%
1980
21%
720
62%
720
36%
1181
October11th to 20thNight
50%
720
33%
2102
24%
720
61%
720
36%
1194
October21st to endNight
52%
792
32%
2376
26%
792
63%
792
35%
1340
November1st to 10thNight
50%
740
30%
2327
25%
740
61%
740
36%
1280
November11th to 20thNight
40%
760
30%
2470
20%
760
56%
760
30%
1368
November21st to endNight
40%
760
27%
2470
18%
760
54%
760
28%
1447
December1st to 10thNight
33%
760
27%
2470
14%
760
50%
760
23%
1526
December11th to 20thNight
34%
759
27%
2899
16%
758
47%
758
22%
1651
December21st to endNight
29%
829
15%
4418
12%
817
41%
817
11%
2807

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%5%25%5%35%5%6%8%42%
74888
Night
12%5%25%5%345%5%8%45%
74895
TransparencyDay
39%5%11%20%19%5%
74611
Night
37%5%11%20%20%7%
74691
SeeingDay
16%9%21%24%20%10%
13852
Night
15%9%21%29%22%4
23954

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 10thDay
17%7%34424445%46%
1706
11th to 20thDay
16%8%25%433446%46%
1656
21st to endDay
19%6%35%4345%46%43%
1832
February1st to 10thDay
16%7%36%6%346%5%7%38%
1800
11th to 20thDay
21%6%34424446%43%
1748
21st to endDay
19%7%36%5%34445%39%
1480
March1st to 10thDay
15%434424337%50%
1885
11th to 20thDay
18%6%345%34446%42%
1980
21st to endDay
16%5%25%5%345%6%6%42%
2178
April1st to 10thDay
13%5%25%4245%5%6%48%
1980
11th to 20thDay
12%5%25%5%35%45%7%48%
2120
21st to endDay
8%424435%45%7%53%
2326
May1st to 10thDay
8%6%245%345%5%7%51%
2340
11th to 20thDay
10%6%35%6%36%6%6%8%40%
2301
21st to endDay
10%436%6%45%6%6%9%42%
2531
June1st to 10thDay
10%6%36%7%5%7%7%7%9%34%
2340
11th to 20thDay
6%3246%47%7%8%11%41%
2340
21st to endDay
6%425%6%48%7%7%11%40%
2340
July1st to 10thDay
9%6%37%8%5%7%8%9%10%29%
2340
11th to 20thDay
9%436%7%5%7%8%8%11%32%
2340
21st to endDay
6%5%36%7%5%8%8%9%12%31%
2547
August1st to 10thDay
8%5%36%8%5%8%8%10%11%28%
2327
11th to 20thDay
10%6%36%7%5%6%7%8%9%33%
2196
21st to endDay
12%7%48%7%46%6%7%9%30%
2346
September1st to 10thDay
11%5%36%6%45%7%7%8%38%
1980
11th to 20thDay
14%6%25%5%45%5%6%7%42%
1980
21st to endDay
14%6%245%345%45%47%
1980
October1st to 10thDay
13%424423447%54%
1980
11th to 20thDay
13%5%13424348%55%
1855
21st to endDay
11%5%24324345%55%
1980
November1st to 10thDay
12%5%2442334457%
1747
11th to 20thDay
14%424424446%53%
1710
21st to endDay
14%5%245%345%46%48%
1710
December1st to 10thDay
17%9%35%5%35%45%6%39%
1710
11th to 20thDay
19%6%35%433335%46%
2153
21st to endDay
22%6%25%42345%7%39%
3124
January1st to 10thNight
17%7%24434446%46%
2459
11th to 20thNight
16%7%35%42445%5%44%
2399
21st to endNight
17%6%35%423445%47%
2520
February1st to 10thNight
15%6%25%6%34447%43%
2160
11th to 20thNight
20%6%24423445%44%
2098
21st to endNight
18%6%25%5%345%5%5%43%
1776
March1st to 10thNight
11%7%35%434345%50%
2074
11th to 20thNight
15%5%245%345%5%8%44%
1980
21st to endNight
13%5%24425%5%6%7%48%
2178
April1st to 10thNight
11%4244245%5%9%50%
1980
11th to 20thNight
13%5%244235%5%8%51%
1803
21st to endNight
7%5%2443446%8%54%
1632
May1st to 10thNight
8%424445%46%8%51%
1620
11th to 20thNight
9%5%25%7%46%5%7%8%42%
1592
21st to endNight
9%5%35%5%36%5%6%8%44%
1744
June1st to 10thNight
7%5%26%6%47%6%8%11%37%
1620
11th to 20thNight
6%325%5%35%5%8%12%46%
1620
21st to endNight
6%4247%37%6%9%12%39%
1620
July1st to 10thNight
8%5%36%7%37%6%8%13%35%
1620
11th to 20thNight
7%435%5%5%7%7%11%13%34%
1620
21st to endNight
6%425%6%47%8%9%13%36%
1771
August1st to 10thNight
5%6%36%6%47%8%7%14%33%
1611
11th to 20thNight
10%426%8%5%7%7%6%10%35%
1700
21st to endNight
13%6%35%7%45%6%7%9%35%
1989
September1st to 10thNight
8%5%36%7%45%6%8%11%39%
1980
11th to 20thNight
12%5%26%6%345%6%7%45%
1980
21st to endNight
11%6%26%4346%5%7%46%
1980
October1st to 10thNight
12%5%25%4245%46%52%
1980
11th to 20thNight
12%5%25%333345%56%
2102
21st to endNight
11%4135%24445%56%
2376
November1st to 10thNight
11%5%24323346%56%
2327
11th to 20thNight
14%5%24413345%55%
2470
21st to endNight
14%5%25%5%33447%48%
2470
December1st to 10thNight
16%6%245%335%5%7%44%
2470
11th to 20thNight
17%6%24323345%50%
3042
21st to endNight
19%8%36%5%35%45%7%35%
4532

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 10thDay
41%37%20%24%5%
1707
11th to 20thDay
41%37%20%22%7%
1656
21st to endDay
42%35%19%24%7%
1832
February1st to 10thDay
45%48%18%19%6%
1800
11th to 20thDay
43%45%20%23%6%
1758
21st to endDay
47%48%15%19%8%
1480
March1st to 10thDay
37%29%18%23%11%
1885
11th to 20thDay
43%410%18%18%6%
1980
21st to endDay
41%49%22%18%5%
2178
April1st to 10thDay
37%410%21%21%7%
1980
11th to 20thDay
36%47%21%23%9%
2120
21st to endDay
31%410%26%25%4
2326
May1st to 10thDay
31%5%12%23%24%4
2340
11th to 20thDay
40%6%16%21%15%2
2305
21st to endDay
37%6%11%25%18%2
2531
June1st to 10thDay
44%7%15%22%11%2
2340
11th to 20thDay
33%8%19%26%14%1
2340
21st to endDay
36%9%19%20%14%3
2340
July1st to 10thDay
43%9%20%17%8%2
2275
11th to 20thDay
41%11%19%19%8%2
2271
21st to endDay
40%11%19%22%8%1
2405
August1st to 10thDay
44%10%20%21%5%
2314
11th to 20thDay
44%9%18%18%10%2
2196
21st to endDay
49%7%15%18%10%2
2346
September1st to 10thDay
40%8%15%15%18%4
1980
11th to 20thDay
40%7%10%18%22%3
1980
21st to endDay
39%48%22%21%6%
1980
October1st to 10thDay
32%39%21%28%7%
1980
11th to 20thDay
30%47%26%26%8%
1855
21st to endDay
32%26%16%32%12%
1980
November1st to 10thDay
32%28%15%30%13%
1747
11th to 20thDay
34%36%19%26%12%
1710
21st to endDay
38%37%20%25%7%
1710
December1st to 10thDay
46%48%18%18%7%
1710
11th to 20thDay
43%25%16%25%8%
2150
21st to endDay
44%5%7%19%22%3
3124
January1st to 10thNight
41%46%20%24%6%
2459
11th to 20thNight
42%46%20%21%7%
2399
21st to endNight
41%3420%24%9%
2520
February1st to 10thNight
42%37%19%20%9%
2160
11th to 20thNight
43%35%18%22%9%
2099
21st to endNight
43%48%17%18%11%
1776
March1st to 10thNight
37%37%18%21%14%
2074
11th to 20thNight
39%5%11%17%21%7%
1980
21st to endNight
35%5%9%22%21%7%
2178
April1st to 10thNight
33%311%22%22%9%
1980
11th to 20thNight
32%47%24%23%11%
1803
21st to endNight
28%5%11%24%25%7%
1632
May1st to 10thNight
30%5%13%24%22%6%
1620
11th to 20thNight
39%6%17%18%18%3
1593
21st to endNight
37%6%12%23%19%3
1745
June1st to 10thNight
38%8%18%21%14%1
1620
11th to 20thNight
29%6%21%30%11%3
1620
21st to endNight
33%8%23%20%13%3
1620
July1st to 10thNight
38%11%22%18%8%3
1575
11th to 20thNight
36%12%26%15%9%2
1566
21st to endNight
34%11%25%21%7%2
1672
August1st to 10thNight
39%11%20%23%6%
1600
11th to 20thNight
41%10%18%18%12%1
1700
21st to endNight
45%8%17%17%11%2
1989
September1st to 10thNight
37%8%16%18%17%4
1980
11th to 20thNight
38%7%13%19%20%5%
1980
21st to endNight
36%5%11%18%22%7%
1980
October1st to 10thNight
33%49%19%27%8%
1980
11th to 20thNight
31%46%22%27%10%
2102
21st to endNight
31%3419%28%15%
2376
November1st to 10thNight
31%38%17%28%14%
2327
11th to 20thNight
34%26%18%27%14%
2470
21st to endNight
37%37%19%26%9%
2470
December1st to 10thNight
40%5%8%21%21%6%
2470
11th to 20thNight
38%26%17%29%8%
3044
21st to endNight
49%46%20%17%3
4532

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 10thDay
23%23%40%11%2
270
11th to 20thDay
23%21%34%13%8%1
252
21st to endDay
22%27%36%11%4
264
February1st to 10thDay
24%21%35%15%5%
240
11th to 20thDay
38%17%34%11%1
240
21st to endDay
24%22%37%15%2
198
March1st to 10thDay
19%18%35%20%7%1
325
11th to 20thDay
23%16%33%20%7%1
420
21st to endDay
19%18%32%23%7%1
462
April1st to 10thDay
20%15%27%25%12%1
420
11th to 20thDay
13%16%32%21%15%3
412
21st to endDay
15%10%28%26%17%4
420
May1st to 10thDay
13%14%29%25%15%5%
423
11th to 20thDay
14%6%20%28%21%11%
447
21st to endDay
15%5%13%29%25%13%
485
June1st to 10thDay
11%417%25%30%13%
450
11th to 20thDay
8%414%25%26%22%
450
21st to endDay
10%214%31%25%17%
450
July1st to 10thDay
10%38%23%32%23%
445
11th to 20thDay
9%15%23%34%26%
444
21st to endDay
6%27%22%38%25%
488
August1st to 10thDay
13%311%24%28%21%
446
11th to 20thDay
11%16%24%36%22%
439
21st to endDay
15%29%27%30%17%
495
September1st to 10thDay
10%49%29%30%18%
450
11th to 20thDay
16%212%25%31%13%
450
21st to endDay
14%315%26%34%8%
450
October1st to 10thDay
16%5%20%31%18%10%
450
11th to 20thDay
16%8%23%24%23%6%
450
21st to endDay
16%8%24%29%18%4
495
November1st to 10thDay
20%6%27%30%14%3
345
11th to 20thDay
18%16%36%24%5%1
270
21st to endDay
15%14%31%24%12%3
270
December1st to 10thDay
29%18%29%18%6%1
270
11th to 20thDay
26%18%31%19%6%
270
21st to endDay
32%14%29%19%5%1
297
January1st to 10thNight
23%18%30%22%6%1
760
11th to 20thNight
22%15%28%26%9%
739
21st to endNight
22%15%34%25%4
792
February1st to 10thNight
21%13%30%30%6%
720
11th to 20thNight
23%17%30%27%3
703
21st to endNight
21%15%35%26%3
592
March1st to 10thNight
16%15%32%31%6%
720
11th to 20thNight
18%12%33%26%10%
720
21st to endNight
16%15%29%29%11%
792
April1st to 10thNight
15%13%31%28%14%
720
11th to 20thNight
15%11%26%30%17%1
561
21st to endNight
9%9%22%38%21%1
540
May1st to 10thNight
10%7%26%35%20%1
540
11th to 20thNight
13%320%34%25%6%
531
21st to endNight
11%211%34%32%9%
584
June1st to 10thNight
9%29%40%34%6%
540
11th to 20thNight
6%112%30%36%15%
540
21st to endNight
7%28%35%39%9%
540
July1st to 10thNight
10%26%26%43%14%
525
11th to 20thNight
8%1424%48%15%
522
21st to endNight
7%25%27%49%10%
591
August1st to 10thNight
8%36%29%40%14%
537
11th to 20thNight
9%36%24%49%9%
534
21st to endNight
15%38%26%38%10%
603
September1st to 10thNight
8%310%27%41%10%
720
11th to 20thNight
13%212%26%41%6%
720
21st to endNight
12%413%32%35%5%
720
October1st to 10thNight
15%418%31%26%7%
720
11th to 20thNight
12%6%25%30%23%3
720
21st to endNight
15%9%19%32%22%3
792
November1st to 10thNight
13%9%23%32%21%1
740
11th to 20thNight
14%13%27%31%14%1
760
21st to endNight
16%12%27%32%13%1
760
December1st to 10thNight
21%12%27%28%10%1
760
11th to 20thNight
21%12%28%28%11%1
760
21st to endNight
28%14%24%27%7%
836
Page generated at 2024-01-12 07:31:47. Version ac07

Copyright 2024 Attilla Danko


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