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 2005-11-05 to 2017-04-07.

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%
15298
23%
45383
15%
15260
56%
15260
29%
28192

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
31%
718
24%
2327
12%
716
47%
716
25%
1390
January16th to endNight
28%
768
25%
2496
12%
768
44%
768
27%
1506
February1st to 15thNight
29%
701
22%
2287
10%
701
45%
701
26%
1352
February16th to endNight
25%
631
29%
1841
12%
631
43%
631
29%
1111
March1st to 15thNight
35%
720
26%
1980
14%
720
46%
720
30%
1238
March16th to endNight
37%
768
21%
2112
12%
768
45%
768
27%
1385
April1st to 15thNight
36%
686
24%
1808
10%
686
45%
686
33%
1132
April16th to endNight
44%
611
23%
1601
11%
611
50%
611
33%
1019
May1st to 15thNight
47%
495
17%
1485
9%
495
53%
495
27%
967
May16th to endNight
64%
513
18%
1540
14%
513
66%
513
32%
938
June1st to 15thNight
64%
495
17%
1485
16%
495
66%
495
29%
946
June16th to endNight
72%
495
17%
1485
15%
495
74%
495
31%
926
July1st to 15thNight
70%
465
14%
1395
13%
465
70%
465
28%
903
July16th to endNight
72%
522
14%
1469
13%
489
74%
489
30%
931
August1st to 15thNight
69%
494
17%
1474
16%
491
70%
491
27%
977
August16th to endNight
70%
627
17%
1677
13%
627
71%
627
31%
1115
September1st to 15thNight
70%
660
23%
1746
19%
660
71%
660
34%
1110
September16th to endNight
52%
657
19%
1815
16%
657
55%
657
23%
1276
October1st to 15thNight
53%
660
29%
1962
26%
660
60%
660
32%
1191
October16th to endNight
48%
704
35%
2112
23%
704
66%
704
38%
1171
November1st to 15thNight
50%
700
30%
2110
22%
700
61%
700
35%
1202
November16th to endNight
44%
720
28%
2340
19%
720
56%
720
31%
1325
December1st to 15thNight
38%
720
23%
2340
15%
720
49%
720
25%
1452
December16th to endNight
34%
768
23%
2496
15%
768
46%
768
22%
1629

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%244345%5%8%43%
45845
Night
13%5%2442445%7%45%
45580
TransparencyDay
38%412%22%17%4
45546
Night
37%410%21%19%5%
45383
SeeingDay
15%418%22%23%14%
5017
Night
15%6%22%31%20%2
15305

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
17%5%3443435%6%43%
1611
16th to endDay
14%424324345%49%
1728
February1st to 15thDay
14%6%2442345%6%44%
1575
16th to endDay
14%5%24423347%47%
1628
March1st to 15thDay
14%42322435%7%49%
1980
16th to endDay
17%5%2442345%5%44%
2111
April1st to 15thDay
12%41322435%7%51%
1956
16th to endDay
13%415%435%5%46%45%
2038
May1st to 15thDay
13%5%25%5%35%5%6%9%36%
2136
16th to endDay
9%425%5%35%5%5%9%42%
2223
June1st to 15thDay
9%315%5%35%6%7%11%39%
2145
16th to endDay
5%4245%45%7%7%12%41%
2145
July1st to 15thDay
8%6%36%6%46%6%7%10%33%
2145
16th to endDay
7%5%26%7%47%7%8%10%31%
2283
August1st to 15thDay
10%5%25%7%46%7%8%10%30%
2145
16th to endDay
10%5%25%6%46%6%7%9%34%
2160
September1st to 15thDay
9%3145%35%6%6%9%43%
1881
16th to endDay
20%7%25%4245%36%38%
1815
October1st to 15thDay
14%424222236%53%
1667
16th to endDay
12%42342333456%
1760
November1st to 15thDay
13%313312336%56%
1745
16th to endDay
14%433433446%48%
1620
December1st to 15thDay
15%7%1432445%6%45%
1620
16th to endDay
20%8%14322345%42%
1728
January1st to 15thNight
16%5%23422445%48%
2327
16th to endNight
16%425%423345%47%
2496
February1st to 15thNight
15%5%23414445%48%
2278
16th to endNight
13%5%24423346%49%
1841
March1st to 15thNight
14%5%24424446%48%
1980
16th to endNight
16%5%25%424346%43%
2112
April1st to 15thNight
12%5%24423347%49%
1808
16th to endNight
14%424423446%48%
1601
May1st to 15thNight
11%6%26%435%47%9%38%
1484
16th to endNight
8%424335%6%6%10%43%
1538
June1st to 15thNight
9%425%5%36%5%7%11%38%
1485
16th to endNight
7%3245%35%6%7%11%41%
1485
July1st to 15thNight
7%5%26%5%36%7%7%11%35%
1485
16th to endNight
5%425%6%36%6%8%14%36%
1577
August1st to 15thNight
10%5%25%5%45%6%7%9%36%
1485
16th to endNight
8%5%26%5%35%6%8%10%37%
1677
September1st to 15thNight
8%4245%2447%9%44%
1746
16th to endNight
16%7%25%5%25%5%5%5%36%
1815
October1st to 15thNight
14%5%24323435%49%
1962
16th to endNight
12%41422223459%
2112
November1st to 15thNight
13%413323335%55%
2110
16th to endNight
14%32421345%6%50%
2340
December1st to 15thNight
15%6%25%424335%45%
2340
16th to endNight
21%6%34323436%39%
2496

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%37%21%20%4
1612
16th to endDay
37%26%25%20%7%
1728
February1st to 15thDay
39%37%23%21%4
1577
16th to endDay
36%410%25%18%4
1628
March1st to 15thDay
35%38%24%21%5%
1980
16th to endDay
40%410%22%18%3
2112
April1st to 15thDay
30%310%27%21%6%
1956
16th to endDay
37%49%20%20%7%
2038
May1st to 15thDay
42%418%19%12%2
2136
16th to endDay
37%5%15%25%13%2
2227
June1st to 15thDay
35%5%20%25%12%
2145
16th to endDay
32%7%19%23%14%2
2145
July1st to 15thDay
41%8%15%18%11%3
2006
16th to endDay
41%8%19%19%10%
2128
August1st to 15thDay
43%7%16%21%10%
2132
16th to endDay
42%7%17%19%10%1
2160
September1st to 15thDay
36%7%14%19%19%4
1881
16th to endDay
47%47%18%19%2
1815
October1st to 15thDay
33%37%27%22%5%
1667
16th to endDay
31%25%24%26%8%
1760
November1st to 15thDay
31%28%18%29%9%
1745
16th to endDay
37%27%23%23%4
1620
December1st to 15thDay
39%49%22%19%5%
1620
16th to endDay
44%310%18%19%3
1728
January1st to 15thNight
38%39%17%23%7%
2327
16th to endNight
39%26%23%21%5%
2496
February1st to 15thNight
37%28%22%23%5%
2287
16th to endNight
36%210%24%22%3
1841
March1st to 15thNight
37%38%23%21%6%
1980
16th to endNight
41%48%22%17%4
2112
April1st to 15thNight
36%39%22%22%6%
1808
16th to endNight
37%310%19%19%9%
1601
May1st to 15thNight
40%5%15%20%16%
1485
16th to endNight
33%7%16%28%12%1
1540
June1st to 15thNight
38%6%15%24%12%2
1485
16th to endNight
33%8%16%23%14%3
1485
July1st to 15thNight
37%9%15%20%13%3
1395
16th to endNight
34%9%21%20%11%2
1469
August1st to 15thNight
41%6%17%19%13%1
1474
16th to endNight
37%8%19%23%10%1
1677
September1st to 15thNight
33%8%14%20%17%5%
1746
16th to endNight
47%5%9%14%19%3
1815
October1st to 15thNight
37%38%23%22%5%
1962
16th to endNight
30%25%24%26%10%
2112
November1st to 15thNight
32%36%18%26%12%
2110
16th to endNight
33%36%23%25%7%
2340
December1st to 15thNight
41%39%18%20%5%
2340
16th to endNight
45%38%18%19%4
2496

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%14%32%30%5%
90
16th to endDay
14%14%47%13%9%
96
February1st to 15thDay
14%10%51%18%5%
90
16th to endDay
15%9%37%24%12%
132
March1st to 15thDay
15%9%34%29%10%
270
16th to endDay
19%7%29%31%11%
288
April1st to 15thDay
19%10%29%21%17%1
235
16th to endDay
15%323%21%27%8%
210
May1st to 15thDay
15%6%24%25%17%11%
228
16th to endDay
16%110%14%37%19%
267
June1st to 15thDay
13%19%20%32%21%
255
16th to endDay
7%17%27%29%26%
255
July1st to 15thDay
12%9%25%28%23%
245
16th to endDay
8%1414%31%38%
270
August1st to 15thDay
12%15%16%35%27%
253
16th to endDay
11%1419%33%30%
268
September1st to 15thDay
11%16%12%35%31%
255
16th to endDay
27%114%20%24%10%
254
October1st to 15thDay
19%318%29%20%9%
255
16th to endDay
13%319%28%27%7%
272
November1st to 15thDay
20%323%22%20%9%
253
16th to endDay
8%8%28%18%27%6%
90
December1st to 15thDay
16%5%34%33%7%2
90
16th to endDay
31%10%27%20%10%
96
January1st to 15thNight
18%10%32%29%7%
720
16th to endNight
19%8%39%29%2
768
February1st to 15thNight
19%11%36%30%2
704
16th to endNight
16%14%38%27%3
631
March1st to 15thNight
17%9%32%33%6%
720
16th to endNight
18%8%28%34%8%
768
April1st to 15thNight
15%10%33%29%11%
686
16th to endNight
16%6%27%32%15%
611
May1st to 15thNight
14%5%25%36%16%1
495
16th to endNight
11%212%33%36%3
515
June1st to 15thNight
11%112%35%33%6%
495
16th to endNight
5%28%34%44%5%
495
July1st to 15thNight
9%16%35%40%6%
465
16th to endNight
6%15%29%44%12%
522
August1st to 15thNight
12%15%28%45%7%
494
16th to endNight
10%25%27%45%8%
627
September1st to 15thNight
10%17%32%41%6%
660
16th to endNight
22%212%29%30%2
657
October1st to 15thNight
18%419%30%24%4
660
16th to endNight
15%426%29%21%2
704
November1st to 15thNight
15%5%23%35%17%2
700
16th to endNight
15%8%26%32%15%
720
December1st to 15thNight
19%6%28%35%10%
720
16th to endNight
25%7%25%34%6%
768
Page generated at 2017-04-08 05:35:16. Version ac04

Copyright 2017 A. Danko


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