Eldorado Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Eldorado Star Party clear sky chart from 2005-11-05 to 2017-09-21.

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
52%
15475
30%
47024
20%
15432
62%
15432
42%
24943

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
42%
884
30%
2315
14%
883
53%
883
41%
1359
January16th to endNight
45%
768
36%
2304
19%
768
59%
768
40%
1246
February1st to 15thNight
38%
704
31%
2108
15%
698
53%
698
41%
1112
February16th to endNight
29%
632
33%
1894
11%
632
49%
632
40%
985
March1st to 15thNight
34%
672
31%
2112
13%
672
50%
672
36%
1157
March16th to endNight
31%
576
28%
2112
16%
576
49%
576
35%
1064
April1st to 15thNight
27%
539
30%
1819
12%
539
49%
539
38%
930
April16th to endNight
34%
540
33%
1800
15%
540
60%
540
43%
880
May1st to 15thNight
32%
540
26%
1653
15%
540
48%
540
38%
904
May16th to endNight
45%
561
25%
1684
18%
561
58%
561
37%
954
June1st to 15thNight
62%
540
24%
1620
20%
540
72%
540
56%
761
June16th to endNight
70%
540
25%
1620
27%
540
72%
540
45%
854
July1st to 15thNight
78%
510
22%
1530
25%
510
79%
510
46%
806
July16th to endNight
85%
564
30%
1657
36%
531
88%
531
55%
781
August1st to 15thNight
90%
539
30%
1789
38%
536
90%
536
50%
831
August16th to endNight
77%
573
24%
1910
28%
573
79%
573
35%
1062
September1st to 15thNight
78%
540
24%
1929
28%
540
79%
540
35%
1042
September16th to endNight
72%
510
28%
1881
30%
510
75%
510
34%
1005
October1st to 15thNight
65%
495
35%
1815
33%
495
72%
495
45%
829
October16th to endNight
58%
613
37%
2021
25%
613
68%
613
48%
962
November1st to 15thNight
55%
875
31%
2275
15%
875
63%
875
51%
1225
November16th to endNight
47%
900
33%
2340
16%
900
56%
900
45%
1320
December1st to 15thNight
47%
900
33%
2340
16%
900
55%
900
41%
1380
December16th to endNight
39%
960
29%
2496
13%
960
49%
960
40%
1494

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
8%424324346%54%
47826
Night
7%313313347%59%
47230
Cloud CoverDay
8%423324346%54%
47824
Night
7%313323347%59%
47230
TransparencyDay
29%49%20%22%12%
47531
Night
25%410%21%22%14%
47029
SeeingDay
9%421%34%24%5%
5407
Night
8%430%39%15%1
15481

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
11%5%23322237%54%
1632
16th to endDay
9%413324345%58%
1920
February1st to 15thDay
6%323323337%60%
1750
16th to endDay
8%322213335%61%
1580
March1st to 15thDay
12%423323345%54%
1848
16th to endDay
11%414322235%58%
2112
April1st to 15thDay
8%224313346%57%
2125
16th to endDay
8%423313336%58%
2160
May1st to 15thDay
10%424423347%50%
2297
16th to endDay
11%5%24423446%49%
2430
June1st to 15thDay
5%312313447%60%
2340
16th to endDay
8%424335%45%8%49%
2340
July1st to 15thDay
7%4245%36%5%47%46%
2340
16th to endDay
42135%35%5%6%8%51%
2395
August1st to 15thDay
2113435%5%5%8%57%
2160
16th to endDay
8%4246%45%5%6%9%41%
2292
September1st to 15thDay
11%5%26%6%46%5%5%6%40%
2031
16th to endDay
8%4245%24346%51%
1871
October1st to 15thDay
8%414313346%57%
1815
16th to endDay
7%31221233468%
1837
November1st to 15thDay
8%413222348%59%
1583
16th to endDay
8%5%23212235%61%
1620
December1st to 15thDay
13%5%24313335%53%
1620
16th to endDay
10%6%23223345%55%
1728
January1st to 15thNight
9%5%23413235%58%
2315
16th to endNight
8%413323345%59%
2304
February1st to 15thNight
7%5%22313246%60%
2102
16th to endNight
8%31321335%6%60%
1894
March1st to 15thNight
11%413223446%55%
2112
16th to endNight
7%413324345%59%
2112
April1st to 15thNight
7%41321335%8%58%
1819
16th to endNight
6%312214335%65%
1800
May1st to 15thNight
7%422324436%57%
1652
16th to endNight
7%32332345%9%53%
1683
June1st to 15thNight
211121346%8%65%
1620
16th to endNight
421331445%9%59%
1620
July1st to 15thNight
5%31331436%10%57%
1620
16th to endNight
221231335%11%61%
1770
August1st to 15thNight
211222435%8%65%
1800
16th to endNight
6%312325%5%7%11%48%
1910
September1st to 15thNight
6%32342445%9%53%
1929
16th to endNight
8%4133235%6%8%51%
1881
October1st to 15thNight
7%313212336%64%
1815
16th to endNight
5%31231233468%
2021
November1st to 15thNight
6%41331223466%
2275
16th to endNight
8%32331233462%
2340
December1st to 15thNight
10%6%13213246%56%
2340
16th to endNight
8%434423336%55%
2496

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
11%5%23322237%54%
1632
16th to endDay
9%413314345%59%
1920
February1st to 15thDay
6%324323336%60%
1750
16th to endDay
8%312223335%61%
1580
March1st to 15thDay
12%423323336%54%
1848
16th to endDay
11%423312225%59%
2110
April1st to 15thDay
8%324323346%58%
2125
16th to endDay
8%423312336%58%
2160
May1st to 15thDay
10%424423347%50%
2297
16th to endDay
11%5%24423446%50%
2430
June1st to 15thDay
5%212313447%61%
2340
16th to endDay
8%4243245%5%7%50%
2340
July1st to 15thDay
8%4145%46%45%7%47%
2340
16th to endDay
42245%35%5%6%8%52%
2395
August1st to 15thDay
2113335%5%6%8%57%
2160
16th to endDay
9%4147%35%5%5%9%42%
2292
September1st to 15thDay
11%5%26%6%36%5%5%6%40%
2031
16th to endDay
9%42443335%6%51%
1871
October1st to 15thDay
9%414313346%57%
1815
16th to endDay
7%31111233368%
1837
November1st to 15thDay
7%413212347%60%
1583
16th to endDay
9%5%13223235%61%
1620
December1st to 15thDay
13%5%14213335%53%
1620
16th to endDay
10%6%23323345%55%
1728
January1st to 15thNight
9%5%23323235%57%
2315
16th to endNight
8%413223345%59%
2304
February1st to 15thNight
7%5%22312246%60%
2102
16th to endNight
8%31322235%6%60%
1894
March1st to 15thNight
11%413223346%56%
2112
16th to endNight
7%413324245%60%
2112
April1st to 15thNight
7%313213347%58%
1819
16th to endNight
6%311213345%65%
1800
May1st to 15thNight
7%323324446%57%
1652
16th to endNight
8%32332345%9%53%
1683
June1st to 15thNight
211121346%8%65%
1620
16th to endNight
411232445%9%59%
1620
July1st to 15thNight
5%21322337%10%57%
1620
16th to endNight
211131335%11%61%
1770
August1st to 15thNight
211222445%8%65%
1800
16th to endNight
6%3124246%6%11%48%
1910
September1st to 15thNight
6%32442345%9%53%
1929
16th to endNight
9%41332447%8%51%
1881
October1st to 15thNight
7%312212236%64%
1815
16th to endNight
5%31221232468%
2021
November1st to 15thNight
6%31321223466%
2275
16th to endNight
8%41331233462%
2340
December1st to 15thNight
11%5%23213246%56%
2340
16th to endNight
8%5%24413336%55%
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
32%2321%25%14%
1633
16th to endDay
27%36%14%30%17%
1920
February1st to 15thDay
26%35%17%24%22%
1751
16th to endDay
26%3318%30%17%
1580
March1st to 15thDay
32%36%17%21%19%
1848
16th to endDay
30%27%18%24%16%
2112
April1st to 15thDay
27%37%16%24%20%
2125
16th to endDay
27%38%19%21%19%
2160
May1st to 15thDay
33%49%16%21%13%
2297
16th to endDay
36%49%20%20%8%
2434
June1st to 15thDay
22%5%10%27%26%8%
2340
16th to endDay
30%7%13%23%19%5%
2340
July1st to 15thDay
35%6%14%27%14%2
2201
16th to endDay
24%8%19%30%15%1
2246
August1st to 15thDay
23%6%17%31%19%2
2147
16th to endDay
36%8%17%21%14%2
2292
September1st to 15thDay
42%6%12%19%14%4
2031
16th to endDay
32%412%19%20%9%
1871
October1st to 15thDay
28%5%9%22%23%10%
1815
16th to endDay
21%35%15%33%21%
1837
November1st to 15thDay
24%310%24%21%15%
1583
16th to endDay
27%36%13%23%25%
1620
December1st to 15thDay
33%35%18%24%13%
1620
16th to endDay
32%26%19%28%10%
1728
January1st to 15thNight
30%25%17%25%19%
2315
16th to endNight
27%35%16%25%21%
2304
February1st to 15thNight
25%37%14%24%25%
2112
16th to endNight
25%35%16%28%20%
1894
March1st to 15thNight
29%36%16%23%19%
2112
16th to endNight
27%49%19%21%17%
2112
April1st to 15thNight
25%410%19%16%22%
1819
16th to endNight
21%410%24%20%18%
1800
May1st to 15thNight
27%410%23%19%13%
1653
16th to endNight
27%7%14%21%22%7%
1685
June1st to 15thNight
15%5%15%30%26%6%
1620
16th to endNight
21%7%13%29%21%7%
1620
July1st to 15thNight
22%6%18%31%18%3
1530
16th to endNight
14%6%21%36%19%1
1657
August1st to 15thNight
16%6%14%31%27%3
1789
16th to endNight
26%8%18%26%15%3
1910
September1st to 15thNight
26%7%14%25%20%5%
1929
16th to endNight
28%6%14%24%15%11%
1881
October1st to 15thNight
21%312%27%23%11%
1815
16th to endNight
20%36%15%30%23%
2021
November1st to 15thNight
22%37%23%27%16%
2275
16th to endNight
26%37%12%22%28%
2340
December1st to 15thNight
30%38%19%23%15%
2340
16th to endNight
31%37%16%24%16%
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
13%5%33%33%12%2
90
16th to endDay
9%13%31%32%13%
96
February1st to 15thDay
6%6%35%28%20%2
90
16th to endDay
9%448%28%8%
81
March1st to 15thDay
16%438%25%13%1
90
16th to endDay
47%33%37%16%1
96
April1st to 15thDay
8%15%44%27%4
244
16th to endDay
5%13%42%26%10%1
270
May1st to 15thDay
14%8%41%27%7%
434
16th to endDay
15%5%30%36%11%
517
June1st to 15thDay
5%218%48%22%2
495
16th to endDay
9%114%42%27%4
495
July1st to 15thDay
7%16%45%35%4
475
16th to endDay
3435%44%11%
444
August1st to 15thDay
4228%48%15%
315
16th to endDay
10%19%31%33%13%
332
September1st to 15thDay
6%6%26%44%15%
186
16th to endDay
10%421%47%14%
105
October1st to 15thDay
37%44%38%5%
90
16th to endDay
10%322%30%30%3
96
November1st to 15thDay
20%6%24%28%17%2
90
16th to endDay
26%12%24%17%16%2
90
December1st to 15thDay
23%322%25%17%7%
90
16th to endDay
13%9%47%22%6%
96
January1st to 15thNight
12%6%33%39%9%
888
16th to endNight
11%6%34%37%9%
768
February1st to 15thNight
11%8%37%34%7%
704
16th to endNight
10%10%46%28%3
632
March1st to 15thNight
14%6%43%29%5%
672
16th to endNight
7%9%49%30%3
576
April1st to 15thNight
7%10%53%25%3
539
16th to endNight
46%51%32%5%
540
May1st to 15thNight
6%9%50%27%5%
540
16th to endNight
9%338%36%11%
563
June1st to 15thNight
230%55%9%
540
16th to endNight
3120%53%20%1
540
July1st to 15thNight
6%8%56%25%1
510
16th to endNight
115%54%36%1
564
August1st to 15thNight
2243%47%4
539
16th to endNight
8%6%41%38%4
573
September1st to 15thNight
6%6%44%37%4
540
16th to endNight
10%9%49%27%2
510
October1st to 15thNight
8%220%48%19%1
495
16th to endNight
6%328%37%21%2
613
November1st to 15thNight
8%329%40%17%1
875
16th to endNight
11%5%31%36%14%1
900
December1st to 15thNight
14%5%30%38%10%
900
16th to endNight
11%7%36%34%9%
960
Page generated at 2017-09-22 06:35:38. Version ac04

Copyright 2017 A. Danko


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