CopperHead Ridge Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the CopperHead Ridge Observatory clear sky chart from 2005-11-06 to 2024-01-14.

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%
24340
22%
74350
15%
24292
55%
24292
28%
46140

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
27%
758
24%
2459
10%
757
45%
757
26%
1465
January11th to 20thNight
29%
735
24%
2386
12%
735
45%
735
23%
1507
January21st to endNight
28%
792
28%
2574
14%
792
46%
792
28%
1521
February1st to 10thNight
31%
720
20%
2340
11%
720
43%
720
24%
1436
February11th to 20thNight
20%
700
22%
2184
7%
699
37%
699
22%
1399
February21st to endNight
26%
592
28%
1698
11%
592
42%
592
27%
1076
March1st to 10thNight
34%
720
28%
1980
14%
720
47%
720
32%
1189
March11th to 20thNight
30%
720
21%
1980
10%
720
41%
720
26%
1321
March21st to endNight
32%
792
20%
2178
10%
792
41%
792
26%
1450
April1st to 10thNight
35%
720
24%
1939
10%
720
45%
720
31%
1210
April11th to 20thNight
40%
711
25%
1775
11%
711
49%
711
36%
1103
April21st to endNight
42%
640
25%
1720
13%
640
49%
640
33%
1084
May1st to 10thNight
45%
540
19%
1620
10%
540
52%
540
31%
989
May11th to 20thNight
49%
531
15%
1593
10%
531
53%
531
26%
1053
May21st to endNight
63%
582
17%
1745
15%
582
64%
582
28%
1124
June1st to 10thNight
64%
540
17%
1620
16%
540
65%
540
29%
1032
June11th to 20thNight
64%
540
15%
1620
12%
540
67%
540
31%
1016
June21st to endNight
67%
540
16%
1620
14%
540
69%
540
28%
1044
July1st to 10thNight
70%
525
13%
1575
13%
525
70%
525
28%
1027
July11th to 20thNight
73%
522
14%
1566
13%
522
74%
522
27%
1027
July21st to endNight
71%
591
16%
1672
14%
558
72%
558
30%
1065
August1st to 10thNight
65%
537
14%
1600
12%
534
65%
534
23%
1116
August11th to 20thNight
64%
534
17%
1598
14%
534
65%
534
23%
1099
August21st to endNight
68%
761
17%
1949
12%
761
69%
761
32%
1299
September1st to 10thNight
69%
720
22%
1867
18%
720
70%
720
35%
1196
September11th to 20thNight
61%
720
23%
1980
19%
720
63%
720
29%
1307
September21st to endNight
52%
720
21%
1980
17%
720
57%
720
26%
1358
October1st to 10thNight
56%
720
24%
2130
23%
720
61%
720
32%
1300
October11th to 20thNight
50%
720
32%
2160
25%
720
62%
720
34%
1238
October21st to endNight
49%
792
32%
2376
23%
792
64%
792
36%
1349
November1st to 10thNight
50%
740
29%
2221
23%
740
59%
740
33%
1288
November11th to 20thNight
44%
760
29%
2391
21%
760
56%
760
32%
1362
November21st to endNight
45%
760
28%
2470
19%
760
58%
760
32%
1407
December1st to 10thNight
32%
760
23%
2470
14%
760
45%
760
22%
1583
December11th to 20thNight
37%
760
27%
2933
16%
758
51%
758
24%
1706
December21st to endNight
35%
825
16%
4381
14%
817
47%
817
16%
2394

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%44%
74948
Night
14%6%25%5%345%5%7%45%
74817
TransparencyDay
39%412%23%18%4
74670
Night
39%410%21%20%5%
74614
SeeingDay
16%7%21%24%21%11%
14206
Night
16%7%23%32%20%3
24358

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
18%6%34443346%46%
1706
11th to 20thDay
16%6%35%43435%5%45%
1647
21st to endDay
16%5%25%324445%50%
1782
February1st to 10thDay
15%5%25%5%345%6%7%41%
1620
11th to 20thDay
20%7%24423345%45%
1658
21st to endDay
19%7%35%5%34446%40%
1556
March1st to 10thDay
15%42332435%6%51%
1980
11th to 20thDay
16%5%35%4345%6%8%41%
1980
21st to endDay
17%6%25%5%3446%6%41%
2178
April1st to 10thDay
11%4133245%5%8%55%
2020
11th to 20thDay
13%425%435%45%7%49%
2134
21st to endDay
13%5%25%435%5%5%7%46%
2255
May1st to 10thDay
11%5%25%5%36%5%7%9%43%
2340
11th to 20thDay
13%5%26%5%45%5%6%9%39%
2301
21st to endDay
11%5%35%5%46%5%5%9%40%
2531
June1st to 10thDay
9%5%36%6%45%6%7%10%41%
2340
11th to 20thDay
9%425%5%45%6%8%12%40%
2340
21st to endDay
6%5%25%5%46%7%8%12%39%
2340
July1st to 10thDay
8%6%26%7%46%7%8%10%36%
2340
11th to 20thDay
6%5%26%6%5%7%8%9%12%33%
2340
21st to endDay
7%5%36%7%46%7%7%10%37%
2547
August1st to 10thDay
10%6%26%7%47%7%8%11%34%
2327
11th to 20thDay
10%6%36%8%5%6%7%8%9%30%
2303
21st to endDay
9%5%36%6%45%6%7%10%39%
2387
September1st to 10thDay
10%425%5%35%6%6%7%47%
2088
11th to 20thDay
12%6%15%5%346%5%8%45%
1980
21st to endDay
19%7%26%5%35%446%41%
1980
October1st to 10thDay
14%5%24423346%53%
1828
11th to 20thDay
12%5%24433345%55%
1800
21st to endDay
13%42442334455%
1980
November1st to 10thDay
14%5%23323336%57%
1857
11th to 20thDay
13%42432235%7%54%
1786
21st to endDay
14%5%34433447%50%
1710
December1st to 10thDay
18%8%25%434446%41%
1710
11th to 20thDay
16%5%13223346%54%
2153
21st to endDay
17%6%244345%6%7%42%
3124
January1st to 10thNight
17%6%24432446%48%
2459
11th to 20thNight
16%6%36%5%34445%44%
2386
21st to endNight
16%5%25%424445%50%
2574
February1st to 10thNight
16%6%245%245%5%6%44%
2340
11th to 20thNight
20%6%3442445%5%45%
2184
21st to endNight
17%6%35%433446%45%
1698
March1st to 10thNight
13%5%24424446%52%
1980
11th to 20thNight
17%6%35%445%446%43%
1980
21st to endNight
16%6%26%5%3445%7%42%
2178
April1st to 10thNight
13%5%25%424447%49%
1939
11th to 20thNight
13%4345%2345%7%50%
1775
21st to endNight
15%5%245%2445%6%48%
1720
May1st to 10thNight
9%5%26%5%35%46%7%47%
1620
11th to 20thNight
12%7%36%5%35%5%6%9%37%
1592
21st to endNight
11%6%25%5%45%6%7%9%40%
1744
June1st to 10thNight
9%5%25%6%47%5%7%12%37%
1620
11th to 20thNight
10%5%25%5%45%5%7%11%41%
1620
21st to endNight
8%435%5%47%7%8%11%38%
1620
July1st to 10thNight
6%6%38%6%46%7%7%12%35%
1620
11th to 20thNight
6%5%26%6%5%7%8%8%11%36%
1620
21st to endNight
7%5%35%6%46%6%9%14%35%
1771
August1st to 10thNight
11%6%37%6%46%7%8%10%32%
1611
11th to 20thNight
12%6%46%7%46%7%8%8%33%
1598
21st to endNight
9%7%36%5%35%5%8%10%38%
1949
September1st to 10thNight
8%5%35%5%35%5%7%9%45%
1867
11th to 20thNight
12%7%25%6%345%6%6%43%
1980
21st to endNight
15%8%26%6%35%5%6%6%39%
1980
October1st to 10thNight
13%6%25%434446%49%
2130
11th to 20thNight
14%5%14323446%54%
2160
21st to endNight
13%6%14323345%56%
2376
November1st to 10thNight
14%6%25%32334455%
2221
11th to 20thNight
13%424424445%52%
2391
21st to endNight
15%424324447%51%
2470
December1st to 10thNight
19%6%25%5%24336%43%
2470
11th to 20thNight
17%5%24434445%49%
3042
21st to endNight
20%5%2442445%8%43%
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
43%27%24%19%5%
1707
11th to 20thDay
42%46%22%23%3
1647
21st to endDay
38%26%25%22%7%
1782
February1st to 10thDay
41%410%21%19%5%
1620
11th to 20thDay
42%36%23%20%6%
1667
21st to endDay
46%49%16%18%7%
1556
March1st to 10thDay
35%37%23%25%7%
1980
11th to 20thDay
40%5%10%22%17%6%
1980
21st to endDay
44%310%22%17%3
2178
April1st to 10thDay
29%411%25%25%7%
2020
11th to 20thDay
36%39%23%21%8%
2134
21st to endDay
37%412%26%18%4
2255
May1st to 10thDay
37%417%22%15%4
2340
11th to 20thDay
43%5%17%20%12%3
2305
21st to endDay
41%5%14%27%13%1
2531
June1st to 10thDay
37%5%16%27%14%1
2340
11th to 20thDay
35%5%20%23%15%2
2340
21st to endDay
36%7%18%23%14%1
2340
July1st to 10thDay
40%8%16%20%13%3
2275
11th to 20thDay
38%9%22%20%10%1
2271
21st to endDay
40%7%20%22%10%1
2405
August1st to 10thDay
42%7%17%25%9%
2314
11th to 20thDay
46%8%16%19%10%1
2303
21st to endDay
39%6%19%22%11%3
2387
September1st to 10thDay
36%5%14%21%19%4
2088
11th to 20thDay
38%5%12%20%22%3
1980
21st to endDay
46%46%22%18%3
1980
October1st to 10thDay
35%38%24%26%4
1828
11th to 20thDay
33%27%28%22%8%
1800
21st to endDay
33%36%24%25%9%
1980
November1st to 10thDay
32%27%22%28%8%
1857
11th to 20thDay
33%27%24%27%7%
1786
21st to endDay
36%38%23%25%5%
1710
December1st to 10thDay
44%39%22%19%4
1710
11th to 20thDay
33%28%22%27%9%
2150
21st to endDay
43%27%25%20%2
3124
January1st to 10thNight
39%29%20%23%7%
2459
11th to 20thNight
44%38%19%22%5%
2386
21st to endNight
38%35%23%25%6%
2574
February1st to 10thNight
41%39%21%20%5%
2340
11th to 20thNight
44%37%18%21%7%
2186
21st to endNight
41%210%20%20%6%
1698
March1st to 10thNight
35%37%21%24%9%
1980
11th to 20thNight
44%38%20%19%6%
1980
21st to endNight
43%48%21%19%4
2178
April1st to 10thNight
37%39%21%25%5%
1939
11th to 20thNight
35%29%22%23%9%
1775
21st to endNight
38%311%24%19%5%
1720
May1st to 10thNight
36%5%15%24%18%3
1620
11th to 20thNight
42%6%15%19%15%2
1593
21st to endNight
39%7%14%27%12%1
1745
June1st to 10thNight
38%6%15%25%14%2
1620
11th to 20thNight
37%6%18%22%15%2
1620
21st to endNight
38%8%16%22%12%4
1620
July1st to 10thNight
38%9%18%19%13%3
1575
11th to 20thNight
38%9%21%20%9%3
1566
21st to endNight
36%8%22%22%11%1
1672
August1st to 10thNight
46%8%17%19%10%1
1600
11th to 20thNight
44%9%16%19%10%2
1598
21st to endNight
38%7%19%24%9%3
1949
September1st to 10thNight
35%7%14%21%17%6%
1867
11th to 20thNight
40%7%10%19%22%2
1980
21st to endNight
46%5%11%18%18%4
1980
October1st to 10thNight
38%38%23%24%4
2130
11th to 20thNight
33%36%27%24%7%
2160
21st to endNight
33%26%22%26%11%
2376
November1st to 10thNight
35%36%21%25%11%
2221
11th to 20thNight
34%37%20%26%11%
2391
21st to endNight
34%36%24%27%6%
2470
December1st to 10thNight
45%38%20%20%5%
2470
11th to 20thNight
39%37%18%24%10%
3044
21st to endNight
42%28%23%23%2
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%15%34%22%7%
270
11th to 20thDay
19%14%39%21%6%
249
21st to endDay
21%14%41%18%7%
264
February1st to 10thDay
20%15%36%19%10%
240
11th to 20thDay
33%11%40%11%5%
240
21st to endDay
25%17%33%19%6%
274
March1st to 10thDay
19%11%35%26%9%
420
11th to 20thDay
19%12%41%20%7%
420
21st to endDay
21%11%33%26%8%
462
April1st to 10thDay
19%12%30%24%14%1
420
11th to 20thDay
13%11%30%23%18%4
412
21st to endDay
18%9%28%21%21%3
420
May1st to 10thDay
12%13%27%27%15%6%
423
11th to 20thDay
15%5%18%27%21%13%
447
21st to endDay
16%213%22%31%16%
485
June1st to 10thDay
11%313%28%31%13%
450
11th to 20thDay
12%313%25%26%21%
450
21st to endDay
9%212%32%29%16%
450
July1st to 10thDay
12%18%20%32%26%
445
11th to 20thDay
6%16%25%31%30%
444
21st to endDay
7%38%24%35%24%
488
August1st to 10thDay
14%211%22%29%22%
446
11th to 20thDay
12%17%23%31%25%
439
21st to endDay
11%28%24%33%24%
495
September1st to 10thDay
13%29%18%34%24%
450
11th to 20thDay
13%312%20%32%20%
450
21st to endDay
22%416%26%25%6%
450
October1st to 10thDay
18%5%14%28%23%11%
450
11th to 20thDay
13%6%21%28%24%8%
450
21st to endDay
15%8%23%30%19%5%
495
November1st to 10thDay
20%5%25%26%17%7%
455
11th to 20thDay
14%10%34%25%14%3
346
21st to endDay
14%8%31%27%15%4
270
December1st to 10thDay
23%9%30%29%7%1
270
11th to 20thDay
17%11%30%27%14%1
270
21st to endDay
24%13%29%23%10%2
297
January1st to 10thNight
20%10%36%27%7%
760
11th to 20thNight
20%9%36%30%5%
735
21st to endNight
19%9%40%29%3
792
February1st to 10thNight
19%12%34%31%4
720
11th to 20thNight
24%13%38%24%1
703
21st to endNight
19%14%35%28%4
592
March1st to 10thNight
16%11%35%33%4
720
11th to 20thNight
20%10%34%27%9%
720
21st to endNight
18%10%34%33%6%
792
April1st to 10thNight
16%13%32%30%10%
720
11th to 20thNight
15%9%31%29%15%
711
21st to endNight
17%6%30%35%13%
640
May1st to 10thNight
11%7%30%37%15%1
540
11th to 20thNight
15%6%19%35%24%2
531
21st to endNight
14%211%37%32%3
584
June1st to 10thNight
11%212%39%31%4
540
11th to 20thNight
11%213%33%36%6%
540
21st to endNight
10%110%36%39%4
540
July1st to 10thNight
8%37%30%45%7%
525
11th to 20thNight
7%2432%47%10%
522
21st to endNight
7%26%35%41%8%
591
August1st to 10thNight
14%26%30%40%8%
537
11th to 20thNight
13%35%29%42%7%
534
21st to endNight
10%27%30%43%8%
761
September1st to 10thNight
11%26%33%40%8%
720
11th to 20thNight
15%310%29%38%5%
720
21st to endNight
19%5%13%34%27%2
720
October1st to 10thNight
15%5%16%30%28%6%
720
11th to 20thNight
15%5%24%33%20%3
720
21st to endNight
16%6%23%35%18%2
792
November1st to 10thNight
17%7%22%36%17%2
740
11th to 20thNight
15%8%28%37%12%
760
21st to endNight
15%6%29%35%14%1
760
December1st to 10thNight
21%8%29%35%7%
760
11th to 20thNight
19%6%32%34%9%
760
21st to endNight
25%8%24%35%8%
836
Page generated at 2024-01-11 04:22:38. Version ac07

Copyright 2024 Attilla Danko


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