Valle de Guadalupe
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Valle de Guadalupe clear sky chart from 2005-11-05 to 2017-09-24.

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
78%
16283
34%
47056
31%
16240
80%
16240
51%
23778

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
68%
716
29%
2312
29%
716
73%
716
40%
1195
January16th to endNight
65%
768
36%
2304
31%
768
72%
768
41%
1241
February1st to 15thNight
68%
699
32%
2111
32%
699
73%
699
39%
1167
February16th to endNight
62%
632
29%
1895
31%
632
65%
632
32%
1135
March1st to 15thNight
72%
720
31%
2145
34%
720
76%
720
45%
1116
March16th to endNight
76%
768
32%
2064
29%
768
78%
768
50%
1119
April1st to 15thNight
73%
719
31%
1799
22%
719
75%
719
48%
1040
April16th to endNight
76%
720
34%
1800
22%
720
77%
720
59%
951
May1st to 15thNight
75%
584
31%
1664
23%
584
76%
584
51%
866
May16th to endNight
77%
561
30%
1685
23%
561
77%
561
47%
880
June1st to 15thNight
84%
540
32%
1620
28%
540
84%
540
59%
744
June16th to endNight
94%
540
39%
1620
34%
540
94%
540
77%
630
July1st to 15thNight
90%
510
30%
1530
25%
510
90%
510
64%
664
July16th to endNight
90%
641
35%
1664
27%
602
90%
602
61%
791
August1st to 15thNight
92%
717
36%
1790
24%
713
92%
713
72%
852
August16th to endNight
91%
764
42%
1910
30%
764
91%
764
71%
927
September1st to 15thNight
88%
720
38%
1890
32%
720
89%
720
66%
906
September16th to endNight
89%
692
46%
1914
44%
692
90%
692
72%
834
October1st to 15thNight
80%
660
39%
1815
37%
660
82%
660
55%
913
October16th to endNight
81%
704
39%
2073
39%
704
83%
704
53%
1010
November1st to 15thNight
79%
700
36%
2275
40%
700
82%
700
53%
1028
November16th to endNight
76%
720
35%
2340
40%
720
79%
720
47%
1127
December1st to 15thNight
69%
720
33%
2340
35%
720
72%
720
38%
1251
December16th to endNight
63%
768
32%
2496
31%
768
68%
768
34%
1391

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
4212212346%66%
47859
Night
5%313313346%63%
47259
TransparencyDay
19%2415%26%32%
47561
Night
21%2415%24%31%
47058
SeeingDay
5%7%27%39%14%4
5954
Night
6%25%31%39%15%
16295

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
7%413324335%59%
1623
16th to endDay
9%41342335%6%55%
1920
February1st to 15thDay
7%42331345%6%56%
1751
16th to endDay
11%42442445%7%47%
1579
March1st to 15thDay
6%323313348%58%
1814
16th to endDay
5%32321335%7%61%
2157
April1st to 15thDay
6%32331345%6%57%
2149
16th to endDay
5%312112235%71%
2160
May1st to 15thDay
4312212346%67%
2283
16th to endDay
3323211336%68%
2429
June1st to 15thDay
21221235%7%69%
2340
16th to endDay
11112483%
2340
July1st to 15thDay
123313347%68%
2340
16th to endDay
21222247%9%64%
2386
August1st to 15thDay
11111335%77%
2160
16th to endDay
111213335%74%
2292
September1st to 15thDay
11122243473%
2069
16th to endDay
111112482%
1904
October1st to 15thDay
4213212345%68%
1815
16th to endDay
421221223471%
1796
November1st to 15thDay
3312322436%65%
1584
16th to endDay
5%314213346%63%
1620
December1st to 15thDay
8%41441345%7%54%
1620
16th to endDay
10%41432435%453%
1728
January1st to 15thNight
6%414423346%58%
2312
16th to endNight
10%313312347%56%
2304
February1st to 15thNight
6%425%413336%56%
2101
16th to endNight
12%6%25%424446%47%
1895
March1st to 15thNight
7%423313348%58%
2145
16th to endNight
5%42331345%8%57%
2064
April1st to 15thNight
7%5%23324347%56%
1799
16th to endNight
5%41231225%5%65%
1800
May1st to 15thNight
45%14423446%59%
1664
16th to endNight
27%34313236%59%
1684
June1st to 15thNight
1413223347%65%
1620
16th to endNight
111122482%
1620
July1st to 15thNight
131221235%7%68%
1620
16th to endNight
12222347%8%64%
1778
August1st to 15thNight
1121345%8%70%
1800
16th to endNight
1212112326%75%
1910
September1st to 15thNight
121221224473%
1890
16th to endNight
21111112480%
1914
October1st to 15thNight
4313212236%67%
1815
16th to endNight
3312213436%66%
2073
November1st to 15thNight
3213312335%68%
2275
16th to endNight
5%413212345%64%
2340
December1st to 15thNight
9%413424348%53%
2340
16th to endNight
10%6%23314345%54%
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
26%3412%21%32%
1624
16th to endDay
28%36%12%18%29%
1920
February1st to 15thDay
28%2313%20%32%
1751
16th to endDay
35%3316%23%16%
1579
March1st to 15thDay
24%2315%25%27%
1814
16th to endDay
22%26%19%29%18%
2157
April1st to 15thDay
25%2423%29%14%
2149
16th to endDay
17%1421%30%24%
2160
May1st to 15thDay
17%1320%29%27%
2283
16th to endDay
16%1321%36%21%
2432
June1st to 15thDay
12%2414%26%39%
2340
16th to endDay
6%5%19%66%
2340
July1st to 15thDay
14%2213%27%40%
2201
16th to endDay
13%310%24%30%16%
2237
August1st to 15thDay
9%2219%32%34%
2146
16th to endDay
12%2212%34%34%
2292
September1st to 15thDay
14%3111%29%39%
2069
16th to endDay
8%19%34%46%
1904
October1st to 15thDay
18%2315%27%33%
1815
16th to endDay
18%2311%20%44%
1796
November1st to 15thDay
20%2314%20%38%
1584
16th to endDay
21%2411%22%36%
1620
December1st to 15thDay
29%35%15%18%27%
1620
16th to endDay
32%35%16%20%21%
1728
January1st to 15thNight
27%2412%20%32%
2312
16th to endNight
27%25%14%17%31%
2304
February1st to 15thNight
30%2311%17%33%
2112
16th to endNight
36%3313%22%20%
1895
March1st to 15thNight
25%15%15%23%28%
2145
16th to endNight
23%27%19%25%20%
2064
April1st to 15thNight
27%2423%26%15%
1799
16th to endNight
19%15%19%26%27%
1800
May1st to 15thNight
22%26%15%27%25%
1665
16th to endNight
25%1418%27%22%
1685
June1st to 15thNight
17%1215%27%35%
1620
16th to endNight
8%5%19%65%
1620
July1st to 15thNight
13%1213%28%39%
1530
16th to endNight
15%26%27%34%13%
1664
August1st to 15thNight
11%1318%33%31%
1790
16th to endNight
12%1210%35%36%
1910
September1st to 15thNight
13%2110%30%40%
1890
16th to endNight
11%7%37%42%
1914
October1st to 15thNight
19%2316%27%31%
1815
16th to endNight
19%2311%20%41%
2073
November1st to 15thNight
18%2218%18%38%
2275
16th to endNight
22%2315%21%35%
2340
December1st to 15thNight
30%25%14%20%27%
2340
16th to endNight
32%36%14%18%23%
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%9%20%38%12%
102
16th to endDay
12%15%35%26%9%
288
February1st to 15thDay
8%9%40%28%11%1
266
16th to endDay
11%16%33%26%8%2
238
March1st to 15thDay
7%15%33%30%10%3
270
16th to endDay
6%14%37%27%10%3
288
April1st to 15thDay
10%15%37%23%10%2
269
16th to endDay
415%42%25%9%2
270
May1st to 15thDay
10%11%34%31%7%3
288
16th to endDay
5%7%36%36%11%2
330
June1st to 15thDay
2430%40%17%3
315
16th to endDay
218%50%19%8%
315
July1st to 15thDay
13%56%20%7%
305
16th to endDay
216%54%23%11%
327
August1st to 15thDay
113%57%17%9%
315
16th to endDay
212%54%17%12%
332
September1st to 15thDay
5%22%52%13%5%
315
16th to endDay
47%28%44%10%4
288
October1st to 15thDay
212%43%29%10%1
255
16th to endDay
8%5%30%34%16%4
212
November1st to 15thDay
48%17%36%25%6%
90
16th to endDay
10%10%26%22%26%4
90
December1st to 15thDay
410%13%40%26%5%
90
16th to endDay
15%6%19%36%20%1
96
January1st to 15thNight
7%310%37%28%11%
720
16th to endNight
12%49%35%29%9%
768
February1st to 15thNight
7%47%38%33%8%
704
16th to endNight
14%28%43%24%7%
632
March1st to 15thNight
7%47%41%30%8%
720
16th to endNight
7%2440%33%11%
768
April1st to 15thNight
9%26%39%34%7%
719
16th to endNight
6%27%39%33%10%
720
May1st to 15thNight
5%17%36%37%11%
585
16th to endNight
325%36%44%8%
563
June1st to 15thNight
21438%44%9%
540
16th to endNight
124%58%14%
540
July1st to 15thNight
113%65%17%
510
16th to endNight
28%60%27%
641
August1st to 15thNight
11%59%27%
717
16th to endNight
27%51%37%
764
September1st to 15thNight
219%54%23%
720
16th to endNight
3129%44%19%
692
October1st to 15thNight
5%2435%38%13%
660
16th to endNight
5%432%36%20%
704
November1st to 15thNight
415%37%34%15%
700
16th to endNight
7%25%35%32%17%
720
December1st to 15thNight
11%27%35%30%11%
720
16th to endNight
14%49%36%26%9%
768
Page generated at 2017-09-25 06:02:19. Version ac04

Copyright 2017 A. Danko


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