Coronado State Monument
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Coronado State Monument clear sky chart from 2005-11-06 to 2024-03-08.

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
56%
24354
31%
79780
21%
24254
66%
24254
40%
40566

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
55%
757
30%
4017
26%
736
70%
736
27%
1991
January11th to 20thNight
52%
757
39%
3944
26%
740
66%
740
33%
1533
January21st to endNight
50%
825
23%
4287
24%
814
66%
814
26%
2151
February1st to 10thNight
48%
760
32%
2470
22%
760
63%
760
44%
1208
February11th to 20thNight
42%
743
30%
2221
17%
740
57%
740
39%
1206
February21st to endNight
38%
628
37%
1884
19%
628
58%
628
44%
949
March1st to 10thNight
43%
750
36%
2112
17%
750
59%
750
43%
1149
March11th to 20thNight
47%
720
32%
1980
17%
720
58%
720
41%
1113
March21st to endNight
44%
743
33%
2129
16%
743
60%
743
40%
1150
April1st to 10thNight
38%
540
35%
1800
18%
540
60%
540
40%
849
April11th to 20thNight
37%
533
34%
1777
19%
533
59%
533
36%
878
April21st to endNight
38%
540
34%
1800
18%
540
61%
540
40%
837
May1st to 10thNight
44%
540
31%
1800
20%
540
61%
540
42%
853
May11th to 20thNight
47%
531
25%
1679
18%
531
58%
531
36%
897
May21st to endNight
50%
584
33%
1582
18%
582
63%
582
49%
826
June1st to 10thNight
60%
540
29%
1440
20%
540
66%
540
47%
764
June11th to 20thNight
61%
540
35%
1440
23%
540
69%
540
59%
715
June21st to endNight
64%
540
25%
1440
19%
540
67%
540
43%
825
July1st to 10thNight
70%
525
17%
1496
15%
525
71%
525
33%
918
July11th to 20thNight
74%
522
17%
1566
16%
522
76%
522
33%
919
July21st to endNight
73%
591
15%
1674
15%
558
74%
558
26%
1078
August1st to 10thNight
77%
537
16%
1634
15%
534
78%
534
34%
948
August11th to 20thNight
71%
534
21%
1778
22%
534
74%
534
30%
1037
August21st to endNight
78%
594
24%
1980
27%
594
81%
594
40%
1033
September1st to 10thNight
70%
540
28%
1800
29%
540
74%
540
34%
994
September11th to 20thNight
73%
540
37%
1800
34%
540
79%
540
44%
896
September21st to endNight
68%
620
34%
2014
29%
620
75%
620
50%
953
October1st to 10thNight
60%
720
31%
2160
21%
720
67%
720
44%
1137
October11th to 20thNight
65%
720
41%
2160
25%
720
76%
720
60%
944
October21st to endNight
61%
792
40%
2376
24%
792
73%
792
54%
1116
November1st to 10thNight
65%
740
44%
2220
28%
740
77%
740
63%
959
November11th to 20thNight
62%
933
39%
2453
23%
933
70%
933
63%
1186
November21st to endNight
55%
950
37%
2470
21%
950
64%
950
47%
1365
December1st to 10thNight
54%
950
36%
2645
21%
950
64%
950
49%
1360
December11th to 20thNight
49%
948
31%
3115
19%
948
59%
948
37%
1660
December21st to endNight
45%
1027
21%
4637
18%
1017
55%
1017
29%
2169

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
33234245%6%8%61%
78761
Night
442442445%7%60%
80850
TransparencyDay
21%5%8%22%27%16%
78487
Night
24%5%8%21%27%15%
80645
SeeingDay
6%13%26%32%20%3
14064
Night
5%8%27%41%18%1
24383

By Month

Percentage Cloud Cover SW (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
26%35%32346%7%59%
2858
11th to 20thDay
231332345%7%67%
2860
21st to endDay
36%36%5%35%5%6%7%53%
3146
February1st to 10thDay
35%25%3345%5%7%59%
1710
11th to 20thDay
25%3442445%7%59%
1844
21st to endDay
15%14424447%63%
1570
March1st to 10thDay
23144245%6%8%60%
2005
11th to 20thDay
35%234245%5%6%61%
1980
21st to endDay
44143235%6%8%60%
2225
April1st to 10thDay
2313323447%68%
2160
11th to 20thDay
331342445%7%64%
2131
21st to endDay
221331435%8%66%
2160
May1st to 10thDay
211332345%8%68%
2160
11th to 20thDay
322443446%7%60%
2213
21st to endDay
221222346%6%69%
2690
June1st to 10thDay
11123245%7%10%65%
2520
11th to 20thDay
1112213447%73%
2520
21st to endDay
33134245%6%8%61%
2520
July1st to 10thDay
3323435%7%8%12%50%
2412
11th to 20thDay
2213435%6%9%13%50%
2340
21st to endDay
42245%47%9%11%13%39%
2545
August1st to 10thDay
32135%35%7%10%12%48%
2293
11th to 20thDay
32245%35%6%8%13%49%
2123
21st to endDay
2213436%6%8%13%52%
2376
September1st to 10thDay
4413425%6%7%8%55%
2160
11th to 20thDay
42133246%6%7%62%
2160
21st to endDay
321332335%6%70%
1939
October1st to 10thDay
5%2134345%6%6%62%
1800
11th to 20thDay
211232324477%
1800
21st to endDay
4213222235%74%
1980
November1st to 10thDay
2212222346%74%
1855
11th to 20thDay
221221336%6%72%
1710
21st to endDay
3423325%336%65%
1710
December1st to 10thDay
3414323348%65%
1530
11th to 20thDay
44245%35%5%6%8%54%
1926
21st to endDay
342442335%8%63%
2830
January1st to 10thNight
29%345%2445%7%55%
4097
11th to 20thNight
4323323345%67%
4110
21st to endNight
5%7%35%4335%5%9%50%
4521
February1st to 10thNight
25%2432335%7%63%
2470
11th to 20thNight
46%2442445%7%58%
2221
21st to endNight
45%2432335%5%66%
1884
March1st to 10thNight
4424433447%62%
2112
11th to 20thNight
5%6%24424435%60%
1980
21st to endNight
5%5%23433447%62%
2129
April1st to 10thNight
4214424347%65%
1800
11th to 20thNight
4424423446%62%
1777
21st to endNight
4323323446%66%
1800
May1st to 10thNight
322432446%7%63%
1800
11th to 20thNight
5%425%335%5%6%6%56%
1679
21st to endNight
322332436%6%65%
1582
June1st to 10thNight
2113435%5%7%10%58%
1440
11th to 20thNight
2213323447%70%
1440
21st to endNight
3325%435%7%7%9%52%
1440
July1st to 10thNight
3325%7%47%8%10%9%43%
1541
11th to 20thNight
2325%6%5%8%6%10%12%42%
1620
21st to endNight
2436%8%48%9%11%13%32%
1773
August1st to 10thNight
33236%46%8%10%13%43%
1643
11th to 20thNight
5%426%6%46%7%8%11%41%
1778
21st to endNight
3213445%6%10%14%48%
1980
September1st to 10thNight
5%3246%36%7%8%9%48%
1800
11th to 20thNight
44134345%5%9%58%
1800
21st to endNight
4213424446%66%
2014
October1st to 10thNight
5%324424447%62%
2160
11th to 20thNight
311222233477%
2160
21st to endNight
3313323335%72%
2376
November1st to 10thNight
2112212235%77%
2220
11th to 20thNight
2312212346%74%
2453
21st to endNight
5%5%23323247%63%
2470
December1st to 10thNight
431332345%6%65%
2645
11th to 20thNight
44245%2446%9%56%
3271
21st to endNight
46%24423446%59%
4864

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
23%7%6%35%25%3
2859
11th to 20thDay
18%414%37%23%3
2860
21st to endDay
31%5%8%25%26%5%
3146
February1st to 10thDay
24%5%9%26%26%10%
1710
11th to 20thDay
25%47%26%28%11%
1854
21st to endDay
23%3419%31%19%
1570
March1st to 10thDay
22%5%5%21%32%16%
2005
11th to 20thDay
25%5%5%19%32%14%
1980
21st to endDay
22%5%5%21%32%14%
2225
April1st to 10thDay
18%35%18%36%21%
2160
11th to 20thDay
21%4417%31%22%
2134
21st to endDay
17%5%6%20%34%18%
2160
May1st to 10thDay
16%35%18%33%24%
2160
11th to 20thDay
23%6%8%19%27%17%
2216
21st to endDay
15%5%7%16%28%29%
2690
June1st to 10thDay
14%5%8%20%27%26%
2520
11th to 20thDay
13%3411%24%44%
2520
21st to endDay
21%47%20%23%27%
2520
July1st to 10thDay
25%9%12%17%19%18%
2348
11th to 20thDay
21%9%17%26%16%11%
2271
21st to endDay
28%11%20%28%11%2
2404
August1st to 10thDay
25%10%19%20%17%10%
2278
11th to 20thDay
25%8%13%22%22%9%
2123
21st to endDay
22%9%14%27%21%7%
2376
September1st to 10thDay
25%7%9%21%24%14%
2160
11th to 20thDay
21%5%10%17%26%20%
2160
21st to endDay
17%35%22%33%20%
1939
October1st to 10thDay
23%5%7%21%25%20%
1800
11th to 20thDay
14%3314%37%29%
1800
21st to endDay
15%46%21%37%18%
1980
November1st to 10thDay
13%25%23%40%17%
1855
11th to 20thDay
14%46%25%39%11%
1710
21st to endDay
24%3423%34%13%
1710
December1st to 10thDay
22%39%33%24%10%
1530
11th to 20thDay
27%5%10%25%26%5%
1924
21st to endDay
22%38%24%30%13%
2830
January1st to 10thNight
28%7%7%29%24%5%
4097
11th to 20thNight
21%48%38%24%6%
4110
21st to endNight
31%39%26%26%5%
4521
February1st to 10thNight
22%49%24%30%11%
2470
11th to 20thNight
26%6%5%23%27%13%
2221
21st to endNight
22%3318%36%19%
1884
March1st to 10thNight
23%5%322%30%17%
2112
11th to 20thNight
26%45%17%33%14%
1980
21st to endNight
24%5%5%17%33%15%
2129
April1st to 10thNight
21%3318%34%21%
1800
11th to 20thNight
24%4415%28%25%
1777
21st to endNight
20%5%7%16%34%19%
1800
May1st to 10thNight
20%47%13%31%24%
1800
11th to 20thNight
28%5%10%18%20%20%
1680
21st to endNight
19%5%7%15%23%30%
1582
June1st to 10thNight
20%6%11%17%20%25%
1440
11th to 20thNight
16%3411%22%43%
1440
21st to endNight
26%6%11%14%16%27%
1440
July1st to 10thNight
32%8%16%16%12%17%
1496
11th to 20thNight
30%9%20%19%13%9%
1566
21st to endNight
36%11%23%21%7%2
1674
August1st to 10thNight
28%10%21%19%12%10%
1634
11th to 20thNight
33%7%18%18%14%9%
1778
21st to endNight
24%7%19%24%18%8%
1980
September1st to 10thNight
30%6%14%19%18%13%
1800
11th to 20thNight
23%5%12%17%21%23%
1800
21st to endNight
20%37%17%29%24%
2014
October1st to 10thNight
24%48%17%23%23%
2160
11th to 20thNight
13%3414%32%34%
2160
21st to endNight
17%3418%38%20%
2376
November1st to 10thNight
13%2422%41%19%
2220
11th to 20thNight
14%3423%40%16%
2453
21st to endNight
25%2419%34%16%
2470
December1st to 10thNight
20%47%31%30%8%
2645
11th to 20thNight
25%5%8%26%29%7%
3272
21st to endNight
26%46%23%31%9%
4864

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
411%39%36%10%
270
11th to 20thDay
10%15%29%33%12%
270
21st to endDay
312%37%32%15%1
297
February1st to 10thDay
5%19%34%30%10%1
270
11th to 20thDay
8%17%43%27%5%
270
21st to endDay
8%28%38%22%4
225
March1st to 10thDay
7%29%32%25%8%
396
11th to 20thDay
12%25%29%24%11%
420
21st to endDay
13%32%32%16%6%
462
April1st to 10thDay
9%26%37%18%9%1
420
11th to 20thDay
11%29%36%19%5%1
412
21st to endDay
7%29%36%22%5%
420
May1st to 10thDay
5%23%42%24%6%1
423
11th to 20thDay
417%35%29%13%2
448
21st to endDay
415%34%33%13%1
645
June1st to 10thDay
27%21%44%25%2
630
11th to 20thDay
29%23%38%26%2
630
21st to endDay
5%5%22%36%29%3
630
July1st to 10thDay
3316%38%35%5%
518
11th to 20thDay
328%33%42%13%
444
21st to endDay
416%32%47%11%
487
August1st to 10thDay
4210%35%42%7%
447
11th to 20thDay
5%214%38%36%6%
437
21st to endDay
3314%37%37%6%
495
September1st to 10thDay
5%416%37%33%6%
450
11th to 20thDay
2425%39%24%6%
450
21st to endDay
38%23%37%22%6%
314
October1st to 10thDay
5%12%25%28%26%4
270
11th to 20thDay
7%8%24%33%23%4
270
21st to endDay
10%12%19%35%22%2
297
November1st to 10thDay
5%15%32%34%13%1
270
11th to 20thDay
39%25%40%20%2
270
21st to endDay
8%20%26%32%13%2
270
December1st to 10thDay
7%12%33%35%13%
270
11th to 20thDay
9%11%31%37%10%1
270
21st to endDay
11%17%36%29%6%
297
January1st to 10thNight
46%31%43%15%1
760
11th to 20thNight
7%8%28%41%15%1
760
21st to endNight
7%8%31%39%15%1
836
February1st to 10thNight
6%10%35%38%11%1
760
11th to 20thNight
8%10%37%38%7%
744
21st to endNight
8%12%40%36%4
628
March1st to 10thNight
6%13%36%34%11%
750
11th to 20thNight
7%11%30%39%12%
720
21st to endNight
7%14%31%39%8%
743
April1st to 10thNight
5%17%38%34%6%
540
11th to 20thNight
6%19%35%32%8%
533
21st to endNight
7%15%38%35%6%1
540
May1st to 10thNight
413%36%39%9%
540
11th to 20thNight
8%10%30%37%13%1
531
21st to endNight
5%9%32%42%12%
584
June1st to 10thNight
25%26%50%16%1
540
11th to 20thNight
26%28%49%15%1
540
21st to endNight
3422%46%24%1
540
July1st to 10thNight
3214%47%32%2
525
11th to 20thNight
2112%39%42%4
522
21st to endNight
227%37%46%6%
591
August1st to 10thNight
418%33%48%7%
537
11th to 20thNight
5%212%46%31%4
534
21st to endNight
3110%42%40%4
594
September1st to 10thNight
5%215%46%30%2
540
11th to 20thNight
5%215%49%27%2
540
21st to endNight
5%220%45%26%1
620
October1st to 10thNight
6%425%46%18%2
720
11th to 20thNight
45%24%46%19%2
720
21st to endNight
5%6%24%40%21%4
792
November1st to 10thNight
25%26%44%21%1
740
11th to 20thNight
36%26%44%18%2
933
21st to endNight
8%11%23%36%20%2
950
December1st to 10thNight
5%7%30%42%14%1
950
11th to 20thNight
7%10%30%41%12%1
950
21st to endNight
9%10%31%40%9%1
1036
Page generated at 2024-03-05 05:24:00. Version ac07

Copyright © 2024 Attilla Danko.


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