Concho Colts Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Concho Colts Observatory clear sky chart from 2005-11-05 to 2017-10-06.

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
61%
15465
33%
47093
24%
15425
71%
15425
47%
23024

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
63%
719
31%
2327
28%
716
72%
716
44%
1113
January16th to endNight
58%
768
35%
2496
29%
768
70%
768
44%
1223
February1st to 15thNight
56%
700
31%
2287
25%
700
67%
700
49%
1054
February16th to endNight
43%
632
40%
1818
23%
632
63%
632
50%
876
March1st to 15thNight
50%
720
38%
1980
23%
720
64%
720
51%
988
March16th to endNight
54%
768
36%
2112
20%
768
67%
768
57%
1022
April1st to 15thNight
43%
618
34%
1877
16%
618
62%
618
48%
869
April16th to endNight
46%
540
37%
1800
22%
540
66%
540
53%
748
May1st to 15thNight
51%
539
34%
1634
21%
539
64%
539
57%
741
May16th to endNight
56%
562
34%
1684
21%
561
68%
561
59%
732
June1st to 15thNight
63%
540
32%
1620
25%
540
69%
540
63%
705
June16th to endNight
74%
540
28%
1620
25%
540
76%
540
58%
737
July1st to 15thNight
70%
510
17%
1530
15%
510
71%
510
31%
924
July16th to endNight
72%
564
13%
1593
10%
531
72%
531
23%
1044
August1st to 15thNight
77%
539
19%
1611
18%
536
77%
536
29%
1000
August16th to endNight
75%
573
23%
1875
24%
573
76%
573
28%
1132
September1st to 15thNight
77%
621
27%
1881
24%
621
80%
621
36%
1080
September16th to endNight
75%
716
41%
1980
28%
716
82%
716
63%
923
October1st to 15thNight
65%
684
38%
2037
24%
684
75%
684
63%
884
October16th to endNight
72%
704
40%
2112
29%
704
81%
704
61%
934
November1st to 15thNight
67%
700
40%
2100
30%
700
76%
700
62%
915
November16th to endNight
62%
720
39%
2283
32%
720
71%
720
53%
1014
December1st to 15thNight
57%
720
35%
2340
28%
720
69%
720
47%
1069
December16th to endNight
48%
768
32%
2496
24%
768
61%
768
37%
1297

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
231342445%6%60%
48096
Night
2213323446%64%
47290
TransparencyDay
23%5%7%16%27%19%
47791
Night
19%49%19%29%18%
47096
SeeingDay
7%10%23%29%19%8%
5332
Night
36%23%34%25%6%
15472

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 15thDay
31342445%5%62%
1611
16th to endDay
242222335%5%64%
1728
February1st to 15thDay
16%22212246%66%
1575
16th to endDay
1423424447%61%
1651
March1st to 15thDay
13133235%47%63%
1980
16th to endDay
121321335%6%66%
2112
April1st to 15thDay
132213446%67%
2069
16th to endDay
2212212335%71%
2160
May1st to 15thDay
1213323347%66%
2313
16th to endDay
221342443467%
2429
June1st to 15thDay
111312335%75%
2340
16th to endDay
12232444468%
2340
July1st to 15thDay
4426%7%47%6%7%9%40%
2340
16th to endDay
5%437%8%5%10%9%9%10%25%
2467
August1st to 15thDay
7%5%26%7%47%8%7%8%33%
2340
16th to endDay
5%425%6%47%7%8%8%40%
2325
September1st to 15thDay
5%325%6%46%6%6%7%45%
2076
16th to endDay
222312345%68%
1980
October1st to 15thDay
31231332473%
1719
16th to endDay
2212112235%72%
1760
November1st to 15thDay
1211212336%73%
1759
16th to endDay
2213213325%70%
1674
December1st to 15thDay
13123235%47%64%
1620
16th to endDay
25%24323447%58%
1728
January1st to 15thNight
14123235%45%64%
2327
16th to endNight
2413323445%63%
2496
February1st to 15thNight
2312312346%66%
2277
16th to endNight
12133245%5%6%65%
1818
March1st to 15thNight
1312312345%68%
1980
16th to endNight
121221335%6%69%
2112
April1st to 15thNight
131221335%6%66%
1877
16th to endNight
1212213245%72%
1800
May1st to 15thNight
2212223236%70%
1634
16th to endNight
1112212125%76%
1684
June1st to 15thNight
2111212235%75%
1620
16th to endNight
1112224345%69%
1620
July1st to 15thNight
44145%36%7%6%9%45%
1620
16th to endNight
4325%5%49%7%10%13%31%
1701
August1st to 15thNight
33145%36%7%9%10%42%
1620
16th to endNight
4325%5%46%8%7%10%41%
1875
September1st to 15thNight
3325%4346%6%8%50%
1881
16th to endNight
212212346%71%
1980
October1st to 15thNight
11221223476%
2037
16th to endNight
2112212335%75%
2112
November1st to 15thNight
112213336%73%
2100
16th to endNight
2312212236%71%
2283
December1st to 15thNight
2313322347%65%
2340
16th to endNight
442342445%6%57%
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
20%5%8%23%31%10%
1612
16th to endDay
20%38%19%35%12%
1728
February1st to 15thDay
21%28%24%23%19%
1575
16th to endDay
21%5%5%21%33%14%
1651
March1st to 15thDay
18%36%16%38%16%
1980
16th to endDay
18%27%16%38%17%
2112
April1st to 15thDay
16%36%17%36%20%
2069
16th to endDay
16%25%13%36%25%
2160
May1st to 15thDay
18%25%16%30%25%
2313
16th to endDay
20%3410%33%26%
2432
June1st to 15thDay
12%247%27%45%
2340
16th to endDay
19%36%8%22%40%
2340
July1st to 15thDay
38%10%11%13%9%16%
2201
16th to endDay
47%13%17%14%6%
2312
August1st to 15thDay
44%11%10%12%14%7%
2325
16th to endDay
37%11%10%15%18%6%
2325
September1st to 15thDay
36%8%9%15%20%10%
2076
16th to endDay
18%36%14%31%25%
1980
October1st to 15thDay
16%25%16%33%25%
1719
16th to endDay
15%26%12%40%22%
1760
November1st to 15thDay
12%26%23%34%19%
1759
16th to endDay
16%25%18%32%25%
1674
December1st to 15thDay
17%5%10%27%26%12%
1620
16th to endDay
23%5%12%24%28%5%
1728
January1st to 15thNight
20%48%22%33%10%
2327
16th to endNight
21%48%21%33%9%
2496
February1st to 15thNight
18%39%23%26%18%
2288
16th to endNight
16%46%26%34%12%
1818
March1st to 15thNight
17%35%15%41%16%
1980
16th to endNight
15%37%17%40%15%
2112
April1st to 15thNight
17%26%19%36%16%
1877
16th to endNight
13%26%18%37%22%
1800
May1st to 15thNight
15%27%19%32%22%
1635
16th to endNight
12%37%14%37%24%
1685
June1st to 15thNight
12%238%25%46%
1620
16th to endNight
15%37%8%21%43%
1620
July1st to 15thNight
31%10%13%17%10%16%
1530
16th to endNight
36%13%24%17%6%1
1593
August1st to 15thNight
31%12%15%15%16%8%
1611
16th to endNight
33%9%15%17%16%7%
1875
September1st to 15thNight
27%8%15%16%21%10%
1881
16th to endNight
13%35%19%31%26%
1980
October1st to 15thNight
12%26%22%31%24%
2037
16th to endNight
12%36%15%35%25%
2112
November1st to 15thNight
12%26%22%36%19%
2100
16th to endNight
15%26%19%30%24%
2283
December1st to 15thNight
18%39%25%29%13%
2340
16th to endNight
23%6%13%24%26%6%
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
6%20%28%28%11%4
90
16th to endDay
6%16%20%27%19%9%
96
February1st to 15thDay
35%26%27%30%6%
90
16th to endDay
10%29%26%19%11%2
219
March1st to 15thDay
8%18%28%25%12%5%
270
16th to endDay
6%21%34%24%10%2
288
April1st to 15thDay
8%22%31%19%13%4
269
16th to endDay
14%22%34%20%7%1
270
May1st to 15thDay
5%16%37%24%12%3
288
16th to endDay
7%14%30%33%11%3
330
June1st to 15thDay
28%34%30%18%5%
315
16th to endDay
4218%41%23%9%
315
July1st to 15thDay
6%112%41%25%12%
305
16th to endDay
12%17%28%28%21%
327
August1st to 15thDay
11%10%26%34%17%
315
16th to endDay
7%110%31%33%16%
332
September1st to 15thDay
8%119%36%23%10%
315
16th to endDay
6%6%24%33%21%6%
315
October1st to 15thDay
16%24%35%23%8%
121
16th to endDay
5%315%34%33%8%
96
November1st to 15thDay
6%6%21%32%20%13%
90
16th to endDay
422%23%35%14%
90
December1st to 15thDay
5%12%28%28%15%8%
90
16th to endDay
14%18%18%37%7%3
96
January1st to 15thNight
48%19%39%20%8%
720
16th to endNight
46%27%35%20%6%
768
February1st to 15thNight
37%29%35%18%5%
704
16th to endNight
213%38%29%14%1
632
March1st to 15thNight
412%29%31%19%3
720
16th to endNight
27%33%37%15%3
768
April1st to 15thNight
314%34%32%11%2
618
16th to endNight
311%36%31%13%2
540
May1st to 15thNight
45%34%39%14%2
540
16th to endNight
15%32%38%20%2
563
June1st to 15thNight
2227%47%18%1
540
16th to endNight
2115%49%29%1
540
July1st to 15thNight
6%9%37%38%7%
510
16th to endNight
6%6%23%48%14%
564
August1st to 15thNight
6%422%51%14%
539
16th to endNight
5%7%29%44%11%
573
September1st to 15thNight
48%32%45%8%
621
16th to endNight
2214%38%32%9%
716
October1st to 15thNight
2425%36%23%7%
684
16th to endNight
3317%35%30%8%
704
November1st to 15thNight
1424%34%26%9%
700
16th to endNight
47%22%31%23%9%
720
December1st to 15thNight
5%9%22%33%24%5%
720
16th to endNight
6%10%30%32%14%5%
768
Page generated at 2017-10-07 11:07:56. Version ac04

Copyright 2017 A. Danko


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