Camp Onas
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camp Onas clear sky chart from 2005-11-05 to

2017-09-12
.

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
31%
15041
20%
46815
9%
15009
43%
15009
22%
29584

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
19%
720
20%
2506
7%
716
36%
716
15%
1581
January16th to endNight
16%
768
22%
2544
5%
768
38%
768
17%
1598
February1st to 15thNight
12%
704
18%
2261
3%
701
30%
701
16%
1453
February16th to endNight
15%
631
27%
1893
6%
631
39%
631
18%
1185
March1st to 15thNight
19%
720
20%
2106
6%
720
35%
720
18%
1355
March16th to endNight
19%
768
23%
2024
8%
768
33%
768
23%
1333
April1st to 15thNight
20%
718
18%
1796
4%
718
28%
718
23%
1203
April16th to endNight
27%
720
19%
1800
5%
720
35%
720
26%
1215
May1st to 15thNight
27%
494
17%
1574
8%
494
37%
494
20%
1029
May16th to endNight
41%
374
15%
1497
12%
374
48%
374
19%
925
June1st to 15thNight
41%
360
15%
1440
12%
360
52%
360
19%
892
June16th to endNight
54%
360
18%
1440
19%
360
62%
360
27%
801
July1st to 15thNight
49%
340
12%
1360
15%
340
52%
340
20%
839
July16th to endNight
57%
383
17%
1425
18%
361
64%
361
28%
778
August1st to 15thNight
61%
581
18%
1651
11%
578
64%
578
33%
1025
August16th to endNight
56%
764
19%
1910
11%
764
58%
764
33%
1273
September1st to 15thNight
45%
707
23%
1768
12%
707
51%
707
33%
1160
September16th to endNight
49%
657
25%
1779
17%
657
56%
657
33%
1120
October1st to 15thNight
39%
660
22%
1974
15%
660
48%
660
25%
1241
October16th to endNight
29%
704
24%
2159
11%
704
46%
704
26%
1299
November1st to 15thNight
30%
700
22%
2277
10%
700
47%
700
24%
1364
November16th to endNight
25%
720
20%
2423
9%
720
39%
720
18%
1544
December1st to 15thNight
20%
720
16%
2520
6%
720
34%
720
14%
1649
December16th to endNight
16%
768
19%
2688
4%
768
35%
768
15%
1722

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
15%6%25%5%3445%7%39%
47858
Night
15%5%2442445%7%42%
46986
Cloud CoverDay
15%5%25%5%3445%7%40%
47867
Night
15%5%2442445%7%42%
46992
TransparencyDay
42%411%22%15%2
47547
Night
41%412%23%16%2
46815
SeeingDay
19%14%27%22%11%4
5713
Night
19%15%29%25%9%
15042

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%45%5%35%5%46%38%
1432
16th to endDay
14%7%26%5%25%45%5%40%
1680
February1st to 15thDay
16%7%35%5%2345%6%38%
1600
16th to endDay
15%7%36%6%35%35%438%
1580
March1st to 15thDay
16%6%36%6%3435%5%37%
1844
16th to endDay
18%6%34423345%42%
2199
April1st to 15thDay
18%6%24424346%41%
2152
16th to endDay
15%425%43445%6%42%
2160
May1st to 15thDay
20%7%245%245%5%7%34%
2388
16th to endDay
16%7%25%4345%6%8%36%
2618
June1st to 15thDay
15%5%245%45%6%5%9%35%
2520
16th to endDay
12%5%25%5%35%5%6%9%38%
2520
July1st to 15thDay
10%5%25%6%35%5%7%9%35%
2520
16th to endDay
8%426%5%36%6%7%8%37%
2645
August1st to 15thDay
13%5%25%5%36%6%6%8%37%
2286
16th to endDay
13%5%2443445%8%42%
2292
September1st to 15thDay
14%5%2442345%7%45%
2112
16th to endDay
15%415%5%24347%44%
1851
October1st to 15thDay
17%5%13424346%44%
1655
16th to endDay
18%5%13323446%44%
1711
November1st to 15thDay
17%6%24423336%45%
1581
16th to endDay
17%5%24324446%44%
1536
December1st to 15thDay
16%7%25%42445%8%38%
1440
16th to endDay
18%7%345%24447%37%
1536
January1st to 15thNight
16%6%26%424446%41%
2506
16th to endNight
16%8%24424446%42%
2544
February1st to 15thNight
14%8%25%5%2345%6%40%
2260
16th to endNight
16%6%23424445%45%
1893
March1st to 15thNight
17%6%13435%347%43%
2093
16th to endNight
18%6%24423335%46%
2024
April1st to 15thNight
17%4243245%6%7%40%
1796
16th to endNight
17%6%14423447%43%
1800
May1st to 15thNight
18%7%335%2446%6%38%
1574
16th to endNight
17%5%2443436%7%41%
1495
June1st to 15thNight
18%5%25%3345%5%6%40%
1440
16th to endNight
10%4135%25%5%6%10%45%
1440
July1st to 15thNight
10%425%5%36%5%7%9%38%
1440
16th to endNight
8%4134346%8%10%43%
1521
August1st to 15thNight
11%414425%5%6%8%44%
1662
16th to endNight
12%5%245%3446%8%41%
1910
September1st to 15thNight
14%5%24324346%48%
1768
16th to endNight
12%6%24423346%48%
1779
October1st to 15thNight
16%5%2432335%5%45%
1974
16th to endNight
18%423322345%48%
2159
November1st to 15thNight
16%425%412335%48%
2277
16th to endNight
17%5%35%42445%7%38%
2423
December1st to 15thNight
20%5%35%435%45%6%36%
2520
16th to endNight
18%6%35%43345%7%38%
2688

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
14%6%46%5%35%446%38%
1432
16th to endDay
14%7%25%5%24446%40%
1680
February1st to 15thDay
16%7%35%5%2346%5%38%
1600
16th to endDay
15%7%45%6%35%35%438%
1580
March1st to 15thDay
16%7%36%6%3435%5%37%
1854
16th to endDay
18%6%35%423345%42%
2198
April1st to 15thDay
18%6%24433346%41%
2152
16th to endDay
15%425%5%2445%6%43%
2160
May1st to 15thDay
20%6%245%25%45%6%35%
2388
16th to endDay
16%6%25%435%5%6%8%36%
2618
June1st to 15thDay
15%5%245%35%6%6%9%34%
2520
16th to endDay
12%426%5%36%5%5%9%38%
2520
July1st to 15thDay
11%5%35%6%35%5%7%9%36%
2520
16th to endDay
8%435%5%36%6%7%9%38%
2645
August1st to 15thDay
13%425%436%6%6%7%38%
2286
16th to endDay
13%4245%3445%8%42%
2292
September1st to 15thDay
14%5%2442345%6%45%
2112
16th to endDay
15%415%5%2445%6%44%
1851
October1st to 15thDay
17%5%13424347%44%
1655
16th to endDay
18%5%23323446%45%
1711
November1st to 15thDay
16%6%34423346%45%
1581
16th to endDay
17%5%2332435%6%44%
1536
December1st to 15thDay
17%6%25%42445%7%39%
1440
16th to endDay
18%7%25%5%24447%37%
1536
January1st to 15thNight
16%6%25%5%24446%42%
2506
16th to endNight
16%8%25%424346%42%
2544
February1st to 15thNight
14%8%345%2345%5%40%
2253
16th to endNight
16%6%23423445%45%
1893
March1st to 15thNight
17%6%23334347%42%
2106
16th to endNight
18%6%24423336%45%
2024
April1st to 15thNight
17%42432446%7%41%
1796
16th to endNight
17%6%2342345%7%42%
1800
May1st to 15thNight
18%7%3442445%6%38%
1574
16th to endNight
16%5%25%42445%7%40%
1495
June1st to 15thNight
18%42442445%7%40%
1440
16th to endNight
10%323425%46%10%45%
1440
July1st to 15thNight
10%5%25%5%36%5%7%9%38%
1440
16th to endNight
8%323435%5%8%11%43%
1521
August1st to 15thNight
10%5%15%335%5%5%8%44%
1662
16th to endNight
12%5%235%245%5%9%41%
1910
September1st to 15thNight
14%5%14423345%48%
1768
16th to endNight
12%6%15%423346%48%
1779
October1st to 15thNight
16%5%24323446%45%
1974
16th to endNight
18%5%23322345%48%
2159
November1st to 15thNight
16%5%25%312335%48%
2277
16th to endNight
17%5%35%42445%7%38%
2423
December1st to 15thNight
19%5%25%435%45%6%36%
2520
16th to endNight
18%6%35%43335%7%38%
2688

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%312%23%10%3
1433
16th to endDay
44%313%23%13%2
1680
February1st to 15thDay
45%412%22%12%2
1603
16th to endDay
48%29%26%11%1
1580
March1st to 15thDay
47%412%22%11%1
1854
16th to endDay
45%210%21%18%2
2199
April1st to 15thDay
44%310%23%13%4
2152
16th to endDay
39%49%19%22%4
2160
May1st to 15thDay
47%5%9%18%15%2
2388
16th to endDay
44%5%13%20%14%1
2622
June1st to 15thDay
43%7%14%22%10%
2520
16th to endDay
41%5%14%23%12%1
2520
July1st to 15thDay
42%5%11%23%14%1
2371
16th to endDay
38%6%12%26%13%2
2478
August1st to 15thDay
41%5%13%21%17%
2273
16th to endDay
38%5%8%23%20%2
2292
September1st to 15thDay
37%5%10%21%23%1
2112
16th to endDay
40%36%22%23%3
1851
October1st to 15thDay
39%414%23%17%2
1655
16th to endDay
40%39%28%16%2
1711
November1st to 15thDay
41%313%20%17%3
1581
16th to endDay
40%310%28%15%1
1536
December1st to 15thDay
44%418%20%11%1
1440
16th to endDay
47%414%21%11%
1536
January1st to 15thNight
44%312%22%13%2
2506
16th to endNight
42%311%27%13%1
2544
February1st to 15thNight
44%412%23%13%2
2261
16th to endNight
40%38%25%18%2
1893
March1st to 15thNight
42%312%23%15%2
2106
16th to endNight
41%210%22%18%3
2024
April1st to 15thNight
41%312%22%16%3
1796
16th to endNight
40%5%8%19%22%3
1800
May1st to 15thNight
45%411%18%18%2
1574
16th to endNight
41%6%15%15%16%3
1497
June1st to 15thNight
42%7%11%22%16%
1440
16th to endNight
33%6%13%31%14%1
1440
July1st to 15thNight
41%6%14%21%14%1
1360
16th to endNight
31%7%18%25%14%2
1425
August1st to 15thNight
34%6%14%24%17%2
1651
16th to endNight
38%5%11%19%22%2
1910
September1st to 15thNight
36%5%10%21%23%1
1768
16th to endNight
37%36%22%27%2
1779
October1st to 15thNight
40%410%26%16%2
1974
16th to endNight
37%310%28%18%1
2159
November1st to 15thNight
38%311%22%18%5%
2277
16th to endNight
44%311%24%14%1
2423
December1st to 15thNight
47%414%20%12%1
2520
16th to endNight
46%313%23%11%1
2688

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
15%43%26%11%3
60
16th to endDay
18%29%36%15%
88
February1st to 15thDay
23%41%24%8%1
117
16th to endDay
21%24%35%14%3
239
March1st to 15thDay
21%24%28%21%4
270
16th to endDay
21%24%32%13%5%2
288
April1st to 15thDay
21%22%30%15%8%1
270
16th to endDay
22%11%33%19%8%4
270
May1st to 15thDay
36%17%20%14%8%2
288
16th to endDay
20%9%27%27%13%1
331
June1st to 15thDay
17%13%26%24%14%3
315
16th to endDay
17%10%33%26%9%2
315
July1st to 15thDay
14%7%25%33%15%3
305
16th to endDay
11%326%30%20%5%
326
August1st to 15thDay
14%5%21%30%19%7%
313
16th to endDay
11%121%32%19%12%
332
September1st to 15thDay
17%9%28%20%15%9%
299
16th to endDay
18%421%27%12%14%
254
October1st to 15thDay
20%5%25%27%13%6%
255
16th to endDay
15%17%36%22%8%
263
November1st to 15thDay
21%11%29%21%14%2
235
16th to endDay
16%26%28%20%7%
156
December1st to 15thDay
18%35%23%13%10%
60
16th to endDay
31%26%35%41
64
January1st to 15thNight
19%24%32%19%3
720
16th to endNight
22%22%34%19%
768
February1st to 15thNight
20%23%37%17%1
704
16th to endNight
20%29%32%16%1
631
March1st to 15thNight
23%23%30%18%2
720
16th to endNight
22%20%34%16%6%
768
April1st to 15thNight
19%22%36%17%4
718
16th to endNight
20%14%33%23%7%
720
May1st to 15thNight
22%10%32%25%8%
494
16th to endNight
18%6%26%34%12%1
375
June1st to 15thNight
18%6%25%35%13%
360
16th to endNight
9%327%49%10%
360
July1st to 15thNight
11%327%40%17%
340
16th to endNight
7%224%42%21%2
383
August1st to 15thNight
13%116%44%22%1
581
16th to endNight
14%216%36%26%2
764
September1st to 15thNight
17%5%25%33%16%1
707
16th to endNight
15%5%23%29%22%3
657
October1st to 15thNight
19%10%26%25%16%1
660
16th to endNight
21%16%29%24%7%
704
November1st to 15thNight
19%15%30%23%10%
700
16th to endNight
19%20%29%22%7%
720
December1st to 15thNight
25%18%30%18%6%
720
16th to endNight
20%22%35%19%2
768
Page generated at 2017-09-13 07:39:02. Version ac04

Copyright 2017 A. Danko


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