Chuchupate Ranger Station
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chuchupate Ranger Station clear sky chart from 2005-11-05 to 2017-09-18.

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
68%
15718
33%
46870
28%
15676
73%
15676
53%
22380

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
55%
716
25%
2449
23%
716
63%
716
37%
1255
January16th to endNight
52%
768
30%
2457
25%
768
62%
768
35%
1328
February1st to 15thNight
57%
700
30%
2110
27%
699
64%
699
41%
1118
February16th to endNight
52%
632
26%
1895
26%
632
58%
632
36%
1080
March1st to 15thNight
55%
720
23%
2151
21%
720
60%
720
38%
1160
March16th to endNight
58%
768
28%
1992
19%
768
65%
768
48%
1106
April1st to 15thNight
48%
719
27%
1799
12%
719
55%
719
46%
1010
April16th to endNight
57%
720
32%
1800
14%
720
64%
720
58%
910
May1st to 15thNight
64%
650
31%
1730
18%
650
68%
650
61%
834
May16th to endNight
57%
555
32%
1679
19%
555
66%
555
57%
732
June1st to 15thNight
76%
360
35%
1440
38%
360
83%
360
63%
486
June16th to endNight
90%
360
43%
1440
51%
360
92%
360
83%
414
July1st to 15thNight
93%
340
34%
1360
41%
340
94%
340
69%
446
July16th to endNight
93%
570
39%
1595
34%
533
94%
533
72%
650
August1st to 15thNight
92%
717
38%
1790
25%
713
92%
713
84%
788
August16th to endNight
94%
764
46%
1910
30%
764
94%
764
84%
843
September1st to 15thNight
92%
720
44%
1800
34%
720
93%
720
81%
812
September16th to endNight
86%
667
46%
1844
41%
667
91%
667
82%
746
October1st to 15thNight
74%
660
35%
1884
33%
660
79%
660
59%
877
October16th to endNight
72%
704
40%
2112
38%
704
79%
704
61%
944
November1st to 15thNight
71%
700
33%
2271
34%
700
76%
700
52%
1018
November16th to endNight
66%
720
33%
2340
31%
720
73%
720
47%
1111
December1st to 15thNight
60%
720
30%
2340
26%
720
67%
720
37%
1235
December16th to endNight
52%
768
27%
2682
25%
768
59%
768
30%
1477

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
2312223346%66%
47919
Night
2313323346%64%
47061
TransparencyDay
17%37%17%28%26%
47607
Night
17%38%19%28%22%
46873
SeeingDay
5%12%30%36%11%3
5950
Night
45%17%33%31%7%
15729

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
341433445%8%53%
1488
16th to endDay
5%9%36%324346%50%
1764
February1st to 15thDay
3435%4245%6%8%51%
1751
16th to endDay
5%7%35%42345%6%49%
1579
March1st to 15thDay
35%23425%6%6%9%49%
1806
16th to endDay
2424325%46%9%53%
2230
April1st to 15thDay
45%2342435%7%56%
2149
16th to endDay
231232345%8%63%
2160
May1st to 15thDay
321221245%7%67%
2220
16th to endDay
3312222346%67%
2432
June1st to 15thDay
112212346%73%
2520
16th to endDay
112385%
2520
July1st to 15thDay
111213335%74%
2520
16th to endDay
111212335%74%
2457
August1st to 15thDay
11111135%81%
2160
16th to endDay
121223479%
2292
September1st to 15thDay
1111225%81%
2160
16th to endDay
1121223480%
1841
October1st to 15thDay
1313213445%67%
1744
16th to endDay
1112323345%69%
1760
November1st to 15thDay
2412213347%65%
1587
16th to endDay
142432435%6%60%
1620
December1st to 15thDay
24243345%6%8%52%
1620
16th to endDay
5%6%35%4335%5%6%50%
1539
January1st to 15thNight
3425%436%5%5%8%50%
2449
16th to endNight
46%26%4245%6%7%49%
2457
February1st to 15thNight
26%35%4246%48%52%
2101
16th to endNight
45%26%5%25%6%47%48%
1895
March1st to 15thNight
25%245%36%5%8%7%47%
2151
16th to endNight
24243245%6%8%53%
1992
April1st to 15thNight
35%35%326%347%53%
1799
16th to endNight
222221335%8%65%
1800
May1st to 15thNight
2311223447%68%
1730
16th to endNight
2212212235%71%
1678
June1st to 15thNight
112212246%75%
1440
16th to endNight
11389%
1440
July1st to 15thNight
111112225%79%
1440
16th to endNight
1111212380%
1706
August1st to 15thNight
111112385%
1800
16th to endNight
11112386%
1910
September1st to 15thNight
111122383%
1800
16th to endNight
111222481%
1844
October1st to 15thNight
12232445%6%67%
1884
16th to endNight
1312212347%67%
2112
November1st to 15thNight
2413315%348%61%
2271
16th to endNight
241332446%8%57%
2340
December1st to 15thNight
34145%36%5%6%7%52%
2340
16th to endNight
5%6%34435%5%6%8%46%
2682

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%49%18%24%17%
1488
16th to endDay
32%39%15%20%18%
1764
February1st to 15thDay
26%38%22%23%15%
1751
16th to endDay
31%48%22%25%6%
1579
March1st to 15thDay
23%5%16%21%19%13%
1806
16th to endDay
23%5%11%27%21%10%
2230
April1st to 15thDay
23%410%27%23%9%
2149
16th to endDay
15%411%26%28%12%
2160
May1st to 15thDay
14%310%22%33%15%
2220
16th to endDay
16%29%24%35%11%
2435
June1st to 15thDay
11%36%16%32%30%
2520
16th to endDay
5%137%27%54%
2520
July1st to 15thDay
10%15%7%21%53%
2371
16th to endDay
11%26%13%31%34%
2305
August1st to 15thDay
8%138%27%51%
2146
16th to endDay
8%138%38%40%
2292
September1st to 15thDay
7%1411%32%42%
2160
16th to endDay
8%1211%39%36%
1841
October1st to 15thDay
16%35%19%30%25%
1744
16th to endDay
14%27%14%31%28%
1760
November1st to 15thDay
17%36%21%30%20%
1587
16th to endDay
22%39%17%25%21%
1620
December1st to 15thDay
23%6%10%21%23%14%
1620
16th to endDay
30%5%9%22%18%13%
1539
January1st to 15thNight
25%5%9%18%23%16%
2449
16th to endNight
29%49%15%20%20%
2457
February1st to 15thNight
23%5%9%19%24%16%
2112
16th to endNight
29%6%10%22%24%7%
1895
March1st to 15thNight
24%5%12%22%20%14%
2151
16th to endNight
20%6%15%25%23%8%
1992
April1st to 15thNight
23%315%26%23%7%
1799
16th to endNight
12%411%29%31%9%
1800
May1st to 15thNight
12%411%26%34%11%
1731
16th to endNight
13%210%26%37%9%
1679
June1st to 15thNight
9%29%19%32%26%
1440
16th to endNight
439%29%53%
1440
July1st to 15thNight
9%5%10%22%51%
1360
16th to endNight
8%25%18%28%36%
1595
August1st to 15thNight
5%1310%31%48%
1790
16th to endNight
6%28%44%37%
1910
September1st to 15thNight
6%1411%32%43%
1800
16th to endNight
5%1315%41%32%
1844
October1st to 15thNight
14%35%21%29%25%
1884
16th to endNight
13%27%16%32%27%
2112
November1st to 15thNight
15%48%21%29%20%
2271
16th to endNight
20%39%17%27%22%
2340
December1st to 15thNight
25%6%9%17%25%15%
2340
16th to endNight
30%6%9%22%19%12%
2682

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
10%23%43%18%2
116
16th to endDay
14%23%33%21%41
262
February1st to 15thDay
8%20%32%31%5%1
266
16th to endDay
12%21%38%22%4
238
March1st to 15thDay
8%22%31%27%9%
270
16th to endDay
8%21%32%27%8%1
288
April1st to 15thDay
13%21%37%18%8%
269
16th to endDay
7%27%35%23%41
270
May1st to 15thDay
10%13%35%28%9%3
288
16th to endDay
8%11%33%35%9%3
330
June1st to 15thDay
29%36%34%13%2
315
16th to endDay
1333%41%13%6%
315
July1st to 15thDay
1120%47%20%8%
305
16th to endDay
2116%51%19%9%
327
August1st to 15thDay
1226%48%13%7%
315
16th to endDay
117%58%12%8%
332
September1st to 15thDay
1330%48%12%4
315
16th to endDay
1431%46%14%1
264
October1st to 15thDay
314%36%36%7%
255
16th to endDay
412%34%37%11%
272
November1st to 15thDay
27%17%31%32%9%
93
16th to endDay
414%35%33%12%
90
December1st to 15thDay
6%8%24%47%12%
90
16th to endDay
12%21%30%26%9%
65
January1st to 15thNight
5%5%26%35%18%8%
720
16th to endNight
8%10%22%33%20%4
768
February1st to 15thNight
5%6%23%34%21%7%
704
16th to endNight
8%9%25%32%18%6%
632
March1st to 15thNight
312%23%34%21%4
720
16th to endNight
49%22%36%24%3
768
April1st to 15thNight
8%8%29%31%18%3
719
16th to endNight
310%25%33%22%4
720
May1st to 15thNight
36%22%34%28%4
651
16th to endNight
47%24%30%29%2
557
June1st to 15thNight
2314%46%30%2
360
16th to endNight
8%45%41%3
360
July1st to 15thNight
1127%59%9%
340
16th to endNight
121%61%14%
570
August1st to 15thNight
1229%55%10%
717
16th to endNight
1121%59%15%
764
September1st to 15thNight
330%51%13%
720
16th to endNight
19%32%44%11%
667
October1st to 15thNight
2315%40%30%7%
660
16th to endNight
3218%30%33%12%
704
November1st to 15thNight
25%16%34%30%10%
700
16th to endNight
4420%35%25%8%
720
December1st to 15thNight
5%6%22%38%22%5%
720
16th to endNight
9%10%22%34%17%4
768
Page generated at 2017-09-19 04:32:28. Version ac04

Copyright 2017 A. Danko


Chuchupate Ranger Station Clear Sky Chart | Charts Home