El Dorado
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the El Dorado 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
50%
15621
26%
47076
18%
15576
57%
15576
32%
27715

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
33%
899
26%
2327
10%
895
42%
895
28%
1508
January16th to endNight
27%
960
27%
2496
9%
960
39%
960
29%
1628
February1st to 15thNight
29%
843
23%
2252
7%
840
39%
840
29%
1443
February16th to endNight
25%
577
27%
1839
11%
577
38%
577
25%
1108
March1st to 15thNight
32%
540
24%
1980
14%
540
45%
540
23%
1181
March16th to endNight
34%
576
22%
2112
16%
576
44%
576
24%
1228
April1st to 15thNight
36%
539
26%
1812
16%
539
50%
539
31%
1001
April16th to endNight
42%
540
25%
1800
20%
540
54%
540
30%
1025
May1st to 15thNight
46%
540
22%
1796
19%
540
56%
540
29%
1073
May16th to endNight
57%
563
23%
1684
19%
561
63%
561
35%
982
June1st to 15thNight
76%
540
21%
1620
21%
540
79%
540
43%
876
June16th to endNight
72%
540
24%
1620
24%
540
75%
540
40%
900
July1st to 15thNight
76%
510
20%
1530
22%
510
78%
510
38%
868
July16th to endNight
85%
564
24%
1594
29%
531
86%
531
43%
860
August1st to 15thNight
84%
539
24%
1682
29%
536
85%
536
45%
867
August16th to endNight
73%
573
22%
1910
26%
573
74%
573
29%
1140
September1st to 15thNight
72%
540
24%
1800
26%
540
73%
540
34%
1009
September16th to endNight
73%
588
33%
1980
33%
588
75%
588
39%
1043
October1st to 15thNight
64%
684
31%
2052
25%
684
68%
684
41%
1124
October16th to endNight
56%
704
36%
2112
26%
704
65%
704
42%
1135
November1st to 15thNight
50%
700
30%
2100
21%
700
58%
700
36%
1192
November16th to endNight
40%
720
33%
2160
21%
720
52%
720
30%
1305
December1st to 15thNight
36%
882
23%
2322
12%
882
44%
882
29%
1538
December16th to endNight
32%
960
23%
2496
10%
960
41%
960
27%
1681

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
12%5%25%5%35%45%7%42%
48043
Night
11%424423447%50%
47273
TransparencyDay
40%5%10%19%19%5%
47744
Night
33%410%21%21%8%
47077
SeeingDay
12%5%18%26%26%10%
5672
Night
14%6%23%30%21%3
15622

By Month

Percentage Cloud Cover SE (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
18%7%1442323446%
1611
16th to endDay
20%7%2331233446%
1728
February1st to 15thDay
18%6%24413345%44%
1609
16th to endDay
18%6%35%42335%440%
1643
March1st to 15thDay
19%7%25%423345%41%
1980
16th to endDay
14%6%35%6%34346%41%
2110
April1st to 15thDay
11%6%245%245%5%6%45%
2136
16th to endDay
12%5%26%5%2445%6%42%
2160
May1st to 15thDay
15%7%36%5%35%446%36%
2152
16th to endDay
8%5%25%6%47%6%6%8%38%
2430
June1st to 15thDay
5%335%7%46%6%7%8%39%
2340
16th to endDay
5%425%6%47%6%9%8%38%
2340
July1st to 15thDay
9%435%6%46%6%8%11%34%
2340
16th to endDay
7%426%7%36%6%8%11%34%
2466
August1st to 15thDay
5%315%5%5%6%6%9%8%40%
2266
16th to endDay
11%4246%47%6%6%8%38%
2292
September1st to 15thDay
11%4245%35%6%46%44%
2160
16th to endDay
9%414435%46%7%47%
1963
October1st to 15thDay
10%5%23424345%52%
1706
16th to endDay
16%41231223359%
1760
November1st to 15thDay
11%424422335%54%
1758
16th to endDay
16%6%34323325%47%
1800
December1st to 15thDay
19%7%35%413335%41%
1565
16th to endDay
17%8%35%42333441%
1728
January1st to 15thNight
16%6%24322335%49%
2327
16th to endNight
19%6%33212235%47%
2496
February1st to 15thNight
15%6%2432333449%
2243
16th to endNight
17%6%23322245%48%
1839
March1st to 15thNight
15%5%24424446%45%
1980
16th to endNight
14%5%25%423347%46%
2112
April1st to 15thNight
9%4144235%46%53%
1812
16th to endNight
10%5%24424447%50%
1800
May1st to 15thNight
11%425%42446%7%47%
1795
16th to endNight
6%425%4345%5%10%47%
1683
June1st to 15thNight
421342446%12%53%
1620
16th to endNight
5%2234345%5%9%54%
1620
July1st to 15thNight
5%423435%5%6%10%47%
1620
16th to endNight
31133246%9%12%51%
1702
August1st to 15thNight
41123245%5%14%52%
1692
16th to endNight
7%414436%5%8%11%41%
1910
September1st to 15thNight
8%3143335%5%8%51%
1800
16th to endNight
7%31342445%6%56%
1980
October1st to 15thNight
9%413323445%57%
2052
16th to endNight
11%31222323461%
2112
November1st to 15thNight
9%424424445%53%
2100
16th to endNight
15%5%2431332352%
2160
December1st to 15thNight
18%6%24323336%44%
2322
16th to endNight
16%7%25%423345%43%
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
43%2418%23%7%
1612
16th to endDay
43%25%16%25%7%
1728
February1st to 15thDay
42%26%20%19%7%
1611
16th to endDay
46%3417%20%7%
1643
March1st to 15thDay
46%37%17%18%5%
1980
16th to endDay
43%5%8%19%20%2
2112
April1st to 15thDay
38%5%8%20%20%6%
2136
16th to endDay
41%5%8%21%20%3
2160
May1st to 15thDay
48%5%8%14%17%5%
2152
16th to endDay
39%7%15%24%9%1
2434
June1st to 15thDay
38%8%12%24%16%1
2340
16th to endDay
38%6%13%21%17%2
2340
July1st to 15thDay
39%8%17%21%12%
2201
16th to endDay
39%8%16%23%10%1
2311
August1st to 15thDay
34%9%16%22%15%1
2252
16th to endDay
41%7%16%20%11%2
2292
September1st to 15thDay
39%6%12%16%19%6%
2160
16th to endDay
32%6%9%20%22%8%
1963
October1st to 15thDay
33%48%17%21%14%
1706
16th to endDay
31%1317%32%13%
1760
November1st to 15thDay
33%36%20%27%8%
1758
16th to endDay
41%2415%27%7%
1800
December1st to 15thDay
46%37%18%16%7%
1565
16th to endDay
46%37%18%19%4
1728
January1st to 15thNight
40%26%17%25%8%
2327
16th to endNight
40%36%17%22%9%
2496
February1st to 15thNight
38%36%19%23%7%
2252
16th to endNight
39%36%21%19%10%
1839
March1st to 15thNight
39%49%18%18%8%
1980
16th to endNight
38%48%21%22%4
2112
April1st to 15thNight
30%5%10%21%21%10%
1812
16th to endNight
33%49%21%24%6%
1800
May1st to 15thNight
35%6%9%21%19%7%
1796
16th to endNight
30%6%15%26%17%1
1685
June1st to 15thNight
22%8%15%30%21%1
1620
16th to endNight
26%5%13%25%23%4
1620
July1st to 15thNight
27%7%19%29%14%2
1530
16th to endNight
22%7%21%30%16%2
1594
August1st to 15thNight
21%6%20%29%17%4
1682
16th to endNight
33%8%16%22%15%3
1910
September1st to 15thNight
30%6%16%19%18%8%
1800
16th to endNight
27%49%20%26%11%
1980
October1st to 15thNight
27%49%17%23%17%
2052
16th to endNight
26%35%15%29%18%
2112
November1st to 15thNight
31%37%19%26%11%
2100
16th to endNight
37%2415%28%12%
2160
December1st to 15thNight
40%49%19%18%7%
2322
16th to endNight
42%37%19%20%5%
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
18%17%42%11%10%
90
16th to endDay
19%26%38%13%2
96
February1st to 15thDay
21%22%40%13%3
90
16th to endDay
19%23%38%11%7%
81
March1st to 15thDay
26%16%41%15%
90
16th to endDay
13%17%30%31%7%
96
April1st to 15thDay
17%15%33%21%9%2
255
16th to endDay
20%9%27%22%15%4
270
May1st to 15thDay
20%6%29%28%12%3
289
16th to endDay
11%5%27%30%19%5%
517
June1st to 15thDay
7%111%39%32%8%
495
16th to endDay
7%213%32%33%10%
495
July1st to 15thDay
8%210%33%34%10%
475
16th to endDay
6%15%22%44%19%
515
August1st to 15thDay
7%323%42%21%
419
16th to endDay
15%1423%32%22%
332
September1st to 15thDay
9%17%22%39%20%
315
16th to endDay
7%10%32%38%11%
183
October1st to 15thDay
5%129%34%20%7%
107
16th to endDay
17%5%18%31%21%5%
96
November1st to 15thDay
13%7%30%37%8%2
90
16th to endDay
23%11%36%16%6%5%
90
December1st to 15thDay
24%12%37%15%7%2
90
16th to endDay
27%16%37%12%42
96
January1st to 15thNight
20%13%28%29%8%
900
16th to endNight
23%10%35%26%4
960
February1st to 15thNight
20%12%35%26%5%
843
16th to endNight
20%14%37%24%3
577
March1st to 15thNight
18%10%34%30%5%
540
16th to endNight
17%9%34%28%10%
576
April1st to 15thNight
11%12%36%26%12%
539
16th to endNight
16%7%29%31%14%
540
May1st to 15thNight
13%5%29%38%12%
540
16th to endNight
7%125%36%24%3
563
June1st to 15thNight
6%9%42%36%5%
540
16th to endNight
5%10%31%43%8%
540
July1st to 15thNight
5%19%33%41%8%
510
16th to endNight
3431%46%13%
564
August1st to 15thNight
5%328%45%16%
539
16th to endNight
10%1327%44%11%
573
September1st to 15thNight
11%5%36%37%8%
540
16th to endNight
8%27%35%39%6%
588
October1st to 15thNight
11%216%32%32%4
684
16th to endNight
14%421%30%25%3
704
November1st to 15thNight
9%6%26%32%22%2
700
16th to endNight
18%8%28%29%14%
720
December1st to 15thNight
22%8%28%29%10%
882
16th to endNight
23%11%28%27%7%
960
Page generated at 2017-10-07 13:07:51. Version ac04

Copyright 2017 A. Danko


El Dorado Clear Sky Chart | Charts Home