Silver City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Silver City 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
62%
15340
34%
47075
25%
15298
72%
15298
47%
23142

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
58%
718
32%
2327
27%
716
69%
716
44%
1141
January16th to endNight
53%
768
38%
2496
28%
768
69%
768
42%
1232
February1st to 15thNight
55%
701
35%
2266
26%
698
70%
698
51%
1032
February16th to endNight
44%
632
42%
1801
24%
632
63%
632
49%
902
March1st to 15thNight
49%
720
40%
1980
21%
720
65%
720
52%
982
March16th to endNight
55%
768
39%
2112
21%
768
69%
768
57%
1005
April1st to 15thNight
46%
578
36%
1837
18%
578
67%
578
48%
840
April16th to endNight
47%
540
43%
1800
24%
540
74%
540
58%
695
May1st to 15thNight
52%
539
33%
1768
23%
539
68%
539
57%
740
May16th to endNight
60%
562
36%
1684
23%
561
72%
561
56%
775
June1st to 15thNight
70%
540
30%
1620
24%
540
75%
540
56%
746
June16th to endNight
72%
540
23%
1620
18%
540
75%
540
47%
806
July1st to 15thNight
74%
510
18%
1530
16%
510
75%
510
33%
917
July16th to endNight
74%
564
15%
1593
15%
531
75%
531
30%
976
August1st to 15thNight
76%
539
20%
1662
21%
536
76%
536
32%
982
August16th to endNight
75%
573
22%
1910
25%
573
76%
573
28%
1152
September1st to 15thNight
75%
540
25%
1800
27%
540
76%
540
31%
1030
September16th to endNight
74%
712
37%
2006
27%
712
80%
712
54%
1007
October1st to 15thNight
73%
684
36%
2052
27%
684
79%
684
56%
964
October16th to endNight
74%
704
43%
2112
31%
704
83%
704
68%
879
November1st to 15thNight
69%
700
43%
2100
31%
700
79%
700
64%
896
November16th to endNight
62%
720
42%
2163
31%
720
71%
720
51%
1043
December1st to 15thNight
61%
720
37%
2340
30%
720
71%
720
46%
1117
December16th to endNight
54%
768
34%
2496
28%
768
64%
768
40%
1283

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
331332445%6%59%
48112
Night
321332345%6%62%
47278
TransparencyDay
22%46%16%28%22%
47807
Night
20%36%17%28%21%
47084
SeeingDay
7%10%23%31%20%6%
5241
Night
45%20%36%26%6%
15347

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
3425%41244364%
1611
16th to endDay
7%324312347%59%
1728
February1st to 15thDay
332321324467%
1588
16th to endDay
232332345%5%64%
1671
March1st to 15thDay
2314423435%64%
1980
16th to endDay
221221225%5%70%
2112
April1st to 15thDay
2212314245%69%
2109
16th to endDay
112211235%77%
2160
May1st to 15thDay
112213445%70%
2180
16th to endDay
2111312435%71%
2429
June1st to 15thDay
2112223238%68%
2340
16th to endDay
22133245%5%6%61%
2340
July1st to 15thDay
5%425%6%46%7%7%9%39%
2340
16th to endDay
7%5%36%7%5%8%8%8%9%28%
2467
August1st to 15thDay
5%5%25%6%48%7%8%9%37%
2286
16th to endDay
6%436%5%46%6%7%8%40%
2292
September1st to 15thDay
7%5%16%5%35%6%7%8%41%
2160
16th to endDay
4213323446%62%
1950
October1st to 15thDay
32123145%46%65%
1705
16th to endDay
2212212236%73%
1760
November1st to 15thDay
1212222236%71%
1759
16th to endDay
3324322325%66%
1797
December1st to 15thDay
441231345%6%62%
1620
16th to endDay
4424423337%58%
1728
January1st to 15thNight
4323423345%62%
2327
16th to endNight
6%324312345%61%
2496
February1st to 15thNight
221331445%6%65%
2262
16th to endNight
3213224335%67%
1801
March1st to 15thNight
221332235%6%67%
1980
16th to endNight
221221322474%
2112
April1st to 15thNight
2112213445%68%
1837
16th to endNight
12212225%78%
1800
May1st to 15thNight
21131225%5%72%
1768
16th to endNight
2112323235%70%
1684
June1st to 15thNight
2212223346%67%
1620
16th to endNight
12233246%6%8%57%
1620
July1st to 15thNight
32246%47%6%9%13%37%
1620
16th to endNight
3325%6%48%7%10%13%33%
1701
August1st to 15thNight
4425%5%25%7%10%12%38%
1671
16th to endNight
3425%6%5%8%7%8%9%39%
1910
September1st to 15thNight
5%425%5%35%7%8%9%43%
1800
16th to endNight
4313312245%68%
2006
October1st to 15thNight
2212213345%68%
2052
16th to endNight
11111123478%
2112
November1st to 15thNight
111212235%75%
2100
16th to endNight
431321233467%
2163
December1st to 15thNight
5%313223347%62%
2340
16th to endNight
4424433346%58%
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
23%3316%33%20%
1612
16th to endDay
24%3217%33%19%
1728
February1st to 15thDay
19%2416%31%26%
1588
16th to endDay
19%3118%34%22%
1671
March1st to 15thDay
21%3113%34%25%
1980
16th to endDay
15%1313%38%26%
2112
April1st to 15thDay
17%1213%39%24%
2109
16th to endDay
11%2110%35%38%
2160
May1st to 15thDay
14%3314%32%32%
2180
16th to endDay
14%3410%29%37%
2432
June1st to 15thDay
15%1110%26%42%
2340
16th to endDay
19%46%13%20%35%
2340
July1st to 15thDay
35%6%12%18%12%13%
2201
16th to endDay
43%9%21%18%7%
2312
August1st to 15thDay
35%8%15%22%14%3
2271
16th to endDay
35%7%15%17%17%7%
2292
September1st to 15thDay
35%6%8%20%19%8%
2160
16th to endDay
20%4317%34%18%
1950
October1st to 15thDay
18%35%16%31%24%
1705
16th to endDay
14%1314%34%30%
1760
November1st to 15thDay
15%2318%33%27%
1759
16th to endDay
21%2314%35%22%
1797
December1st to 15thDay
19%36%23%31%15%
1620
16th to endDay
25%46%22%31%10%
1728
January1st to 15thNight
23%35%15%34%17%
2327
16th to endNight
24%2220%33%17%
2496
February1st to 15thNight
17%3418%30%25%
2273
16th to endNight
17%4220%34%20%
1801
March1st to 15thNight
17%3315%36%24%
1980
16th to endNight
15%2215%38%26%
2112
April1st to 15thNight
16%3215%39%21%
1837
16th to endNight
10%1213%34%36%
1800
May1st to 15thNight
14%1312%33%34%
1769
16th to endNight
16%2312%28%35%
1685
June1st to 15thNight
16%2311%26%39%
1620
16th to endNight
21%48%12%20%32%
1620
July1st to 15thNight
32%7%16%20%13%10%
1530
16th to endNight
35%7%28%22%5%1
1593
August1st to 15thNight
30%8%20%21%13%5%
1662
16th to endNight
34%8%15%19%15%5%
1910
September1st to 15thNight
31%7%14%21%14%10%
1800
16th to endNight
19%25%18%35%17%
2006
October1st to 15thNight
17%36%17%30%25%
2052
16th to endNight
10%1319%31%33%
2112
November1st to 15thNight
12%1319%36%26%
2100
16th to endNight
19%2315%30%27%
2163
December1st to 15thNight
20%35%22%30%16%
2340
16th to endNight
25%38%21%28%11%
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
14%15%30%28%5%5%
90
16th to endDay
8%13%25%31%14%7%
96
February1st to 15thDay
6%6%17%32%31%5%
90
16th to endDay
7%30%30%18%11%1
172
March1st to 15thDay
8%18%34%25%11%2
270
16th to endDay
5%26%37%19%7%3
288
April1st to 15thDay
7%24%34%24%8%1
269
16th to endDay
9%23%37%22%41
270
May1st to 15thDay
6%18%36%28%10%
288
16th to endDay
312%38%34%10%1
330
June1st to 15thDay
45%30%40%16%2
315
16th to endDay
5%220%39%26%5%
315
July1st to 15thDay
5%27%40%34%10%
305
16th to endDay
10%3326%37%17%
327
August1st to 15thDay
9%15%29%39%14%
315
16th to endDay
7%17%31%37%14%
332
September1st to 15thDay
12%210%40%27%6%
315
16th to endDay
7%327%39%19%3
285
October1st to 15thDay
6%421%26%28%12%
107
16th to endDay
9%217%29%29%12%
96
November1st to 15thDay
5%15%21%35%14%7%
90
16th to endDay
7%18%32%32%7%1
90
December1st to 15thDay
4425%35%24%5%
90
16th to endDay
11%19%23%37%5%2
96
January1st to 15thNight
6%7%22%35%21%6%
720
16th to endNight
8%7%23%36%17%5%
768
February1st to 15thNight
36%30%34%20%5%
704
16th to endNight
312%34%35%12%1
632
March1st to 15thNight
310%33%29%19%3
720
16th to endNight
39%28%39%17%2
768
April1st to 15thNight
312%34%36%11%1
578
16th to endNight
212%35%35%11%2
540
May1st to 15thNight
27%32%42%12%1
540
16th to endNight
3329%43%19%1
563
June1st to 15thNight
3217%49%24%2
540
16th to endNight
3214%42%33%3
540
July1st to 15thNight
45%35%44%10%
510
16th to endNight
41423%52%14%
564
August1st to 15thNight
5%1220%51%18%
539
16th to endNight
41423%53%13%
573
September1st to 15thNight
6%1333%48%6%
540
16th to endNight
6%111%39%33%7%
712
October1st to 15thNight
4117%43%28%5%
684
16th to endNight
2317%39%28%8%
704
November1st to 15thNight
2321%36%29%7%
700
16th to endNight
6%419%33%27%8%
720
December1st to 15thNight
7%6%20%35%22%7%
720
16th to endNight
6%10%22%39%16%4
768
Page generated at 2017-10-07 12:07:53. Version ac04

Copyright 2017 A. Danko


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