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 2018-03-21.

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%
15802
20%
49228
9%
15770
43%
15770
22%
31077

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%
780
20%
2716
7%
776
35%
776
16%
1698
January16th to endNight
16%
832
22%
2756
5%
832
38%
832
17%
1735
February1st to 15thNight
12%
764
17%
2453
3%
761
30%
761
15%
1598
February16th to endNight
15%
683
26%
2049
6%
683
38%
683
17%
1307
March1st to 15thNight
18%
780
21%
2281
5%
780
35%
780
18%
1467
March16th to endNight
20%
792
24%
2090
8%
792
34%
792
24%
1366
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
46%
720
23%
1800
12%
720
52%
720
33%
1175
September16th to endNight
51%
717
27%
1941
19%
717
58%
717
34%
1209
October1st to 15thNight
40%
720
21%
2154
14%
720
48%
720
25%
1359
October16th to endNight
30%
768
27%
2356
13%
768
47%
768
27%
1404
November1st to 15thNight
31%
760
22%
2472
10%
760
46%
760
24%
1489
November16th to endNight
25%
780
22%
2625
10%
780
41%
780
19%
1637
December1st to 15thNight
20%
780
16%
2730
5%
780
34%
780
13%
1806
December16th to endNight
16%
832
19%
2912
4%
832
35%
832
15%
1847

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%
49634
Night
15%5%2442445%6%43%
49399
Cloud CoverDay
15%5%25%5%3445%7%40%
49643
Night
15%5%2442445%7%42%
49405
TransparencyDay
42%411%22%15%2
49323
Night
41%411%23%16%2
49228
SeeingDay
19%15%27%22%11%4
6310
Night
19%15%29%25%9%
15803

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%34446%39%
1552
16th to endDay
14%7%25%5%25%45%5%40%
1820
February1st to 15thDay
17%7%35%5%2345%6%38%
1738
16th to endDay
17%7%35%6%35%35%437%
1710
March1st to 15thDay
16%6%35%6%3435%5%38%
1998
16th to endDay
18%6%34423345%41%
2261
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%244235%5%7%44%
2160
16th to endDay
14%415%5%2435%7%44%
2019
October1st to 15thDay
17%5%13424346%44%
1805
16th to endDay
18%5%24323446%45%
1866
November1st to 15thDay
17%6%34323346%44%
1716
16th to endDay
16%424324346%47%
1664
December1st to 15thDay
16%8%25%42345%7%38%
1560
16th to endDay
17%7%345%2445%6%37%
1664
January1st to 15thNight
16%6%26%424446%42%
2716
16th to endNight
16%8%24424446%42%
2756
February1st to 15thNight
15%8%35%5%2345%5%39%
2452
16th to endNight
17%6%23424445%44%
2049
March1st to 15thNight
17%6%13434346%43%
2268
16th to endNight
18%6%24423235%47%
2090
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%424424446%48%
1800
16th to endNight
11%5%24423446%48%
1941
October1st to 15thNight
16%5%3432335%5%45%
2154
16th to endNight
18%413312345%49%
2356
November1st to 15thNight
16%5%24412345%48%
2472
16th to endNight
16%5%35%42445%7%40%
2625
December1st to 15thNight
19%5%35%435%5%5%6%35%
2730
16th to endNight
17%6%25%433447%39%
2912

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%6%46%5%34446%39%
1552
16th to endDay
14%7%25%5%24446%39%
1820
February1st to 15thDay
17%7%35%5%2345%5%38%
1738
16th to endDay
17%6%45%5%3435%437%
1710
March1st to 15thDay
16%7%36%6%3435%5%37%
2008
16th to endDay
18%6%35%423345%42%
2260
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%2442445%6%45%
2160
16th to endDay
14%415%5%2445%6%44%
2019
October1st to 15thDay
17%5%13424346%43%
1805
16th to endDay
18%5%23323446%46%
1866
November1st to 15thDay
17%5%34423346%44%
1716
16th to endDay
16%5%23324346%46%
1664
December1st to 15thDay
17%7%25%423447%39%
1560
16th to endDay
18%7%35%5%2445%7%37%
1664
January1st to 15thNight
16%6%25%5%24446%42%
2716
16th to endNight
16%8%25%424346%42%
2756
February1st to 15thNight
15%8%35%5%2345%5%39%
2445
16th to endNight
17%6%23423445%44%
2049
March1st to 15thNight
17%6%23334346%42%
2281
16th to endNight
18%5%24323236%46%
2090
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
13%5%14423346%48%
1800
16th to endNight
11%5%15%423446%48%
1941
October1st to 15thNight
16%6%2432345%5%45%
2154
16th to endNight
17%5%23322345%49%
2356
November1st to 15thNight
15%5%25%312445%48%
2472
16th to endNight
16%5%25%42445%7%40%
2625
December1st to 15thNight
19%6%25%436%45%6%35%
2730
16th to endNight
17%6%25%43345%7%39%
2912

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
45%312%23%11%4
1553
16th to endDay
44%313%23%13%2
1820
February1st to 15thDay
46%412%22%12%2
1741
16th to endDay
49%29%25%10%1
1710
March1st to 15thDay
46%411%22%13%1
2008
16th to endDay
45%210%21%17%2
2261
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%11%20%23%1
2160
16th to endDay
40%36%23%22%2
2019
October1st to 15thDay
40%413%21%18%1
1805
16th to endDay
39%38%28%17%1
1866
November1st to 15thDay
41%313%21%16%2
1716
16th to endDay
38%39%29%16%2
1664
December1st to 15thDay
44%317%20%11%1
1560
16th to endDay
46%415%20%12%
1664
January1st to 15thNight
43%312%22%14%3
2716
16th to endNight
42%311%27%13%1
2756
February1st to 15thNight
45%412%22%12%2
2453
16th to endNight
42%37%25%18%3
2049
March1st to 15thNight
42%311%24%15%2
2281
16th to endNight
41%210%23%18%3
2090
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%11%21%23%1
1800
16th to endNight
36%37%22%27%2
1941
October1st to 15thNight
40%411%25%16%2
2154
16th to endNight
36%310%30%17%2
2356
November1st to 15thNight
38%312%22%17%5%
2472
16th to endNight
42%311%25%15%1
2625
December1st to 15thNight
48%413%20%11%1
2730
16th to endNight
45%313%23%12%1
2912

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
14%43%26%12%21
90
16th to endDay
19%28%37%15%
132
February1st to 15thDay
26%41%24%7%1
165
16th to endDay
25%22%35%13%3
291
March1st to 15thDay
21%27%29%17%3
330
16th to endDay
21%25%32%13%5%2
311
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%27%20%16%9%
315
16th to endDay
15%6%21%27%14%14%
314
October1st to 15thDay
22%5%25%26%13%6%
315
16th to endDay
15%18%32%21%10%1
322
November1st to 15thDay
22%11%30%21%12%2
280
16th to endDay
14%30%29%18%6%
194
December1st to 15thDay
24%31%24%10%10%
90
16th to endDay
25%35%32%6%1
96
January1st to 15thNight
19%25%33%18%3
780
16th to endNight
21%23%34%19%
832
February1st to 15thNight
21%22%37%17%1
764
16th to endNight
21%28%32%16%1
683
March1st to 15thNight
23%24%30%18%2
780
16th to endNight
21%20%34%17%5%
792
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%34%16%1
720
16th to endNight
14%5%22%29%23%4
717
October1st to 15thNight
19%10%25%25%16%2
720
16th to endNight
21%16%29%24%8%
768
November1st to 15thNight
19%14%30%23%11%
760
16th to endNight
18%20%30%21%7%
780
December1st to 15thNight
24%18%31%18%6%
780
16th to endNight
20%23%34%18%2
832
Page generated at 2018-03-22 11:34:24. Version ac04

Copyright 2018 A. Danko


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