Escondido Ranch
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Escondido Ranch clear sky chart from 2005-11-05 to 2017-12-01.

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
51%
15565
27%
47878
18%
15524
60%
15524
37%
26453

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%
895
24%
2327
11%
895
49%
895
32%
1508
January16th to endNight
41%
797
27%
2333
14%
797
51%
797
30%
1406
February1st to 15thNight
38%
704
28%
2112
12%
700
52%
700
34%
1207
February16th to endNight
30%
632
28%
1894
9%
632
45%
632
37%
1047
March1st to 15thNight
32%
570
28%
2010
13%
570
49%
570
30%
1120
March16th to endNight
27%
576
24%
2112
13%
576
43%
576
31%
1125
April1st to 15thNight
22%
539
26%
1977
8%
539
45%
539
35%
989
April16th to endNight
30%
540
26%
1824
13%
540
49%
540
31%
1040
May1st to 15thNight
27%
539
24%
1620
11%
539
42%
539
36%
921
May16th to endNight
41%
562
29%
1683
17%
561
58%
561
40%
933
June1st to 15thNight
65%
540
25%
1620
22%
540
74%
540
60%
727
June16th to endNight
62%
540
21%
1620
20%
540
68%
540
42%
886
July1st to 15thNight
73%
510
20%
1530
21%
510
77%
510
45%
806
July16th to endNight
80%
564
27%
1594
28%
531
85%
531
51%
792
August1st to 15thNight
84%
539
31%
1787
33%
536
88%
536
58%
754
August16th to endNight
75%
573
24%
1967
26%
573
79%
573
37%
1056
September1st to 15thNight
73%
540
20%
1980
23%
540
75%
540
30%
1119
September16th to endNight
67%
537
23%
1980
24%
537
70%
537
28%
1138
October1st to 15thNight
74%
540
34%
1980
33%
540
79%
540
44%
913
October16th to endNight
63%
729
38%
2265
26%
729
70%
729
50%
1086
November1st to 15thNight
57%
760
28%
2280
18%
760
62%
760
37%
1302
November16th to endNight
58%
974
34%
2534
19%
974
64%
974
46%
1430
December1st to 15thNight
48%
905
27%
2353
17%
905
52%
905
31%
1560
December16th to endNight
43%
960
24%
2496
13%
960
49%
960
33%
1588

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
9%42443445%7%48%
48537
Night
8%31332335%7%55%
48075
TransparencyDay
34%6%10%20%18%9%
48238
Night
27%5%13%23%18%11%
47880
SeeingDay
8%319%37%24%6%
5428
Night
10%328%41%14%1
15572

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
19%43442334445%
1611
16th to endDay
13%5%24323445%48%
1901
February1st to 15thDay
14%5%24422335%50%
1750
16th to endDay
12%5%12223336%55%
1580
March1st to 15thDay
15%6%245%13246%46%
1949
16th to endDay
9%425%424347%51%
2110
April1st to 15thDay
9%42422345%8%51%
1971
16th to endDay
10%5%24424446%48%
2130
May1st to 15thDay
9%5%35%5%35%5%5%7%43%
2331
16th to endDay
6%5%25%5%46%5%7%9%41%
2430
June1st to 15thDay
22135%35%5%6%9%55%
2340
16th to endDay
6%4146%46%6%6%10%42%
2340
July1st to 15thDay
8%425%6%45%5%6%7%43%
2340
16th to endDay
5%3236%35%46%9%48%
2464
August1st to 15thDay
12134245%5%9%60%
2160
16th to endDay
6%425%6%45%5%6%9%41%
2232
September1st to 15thDay
8%437%6%47%5%5%8%38%
1980
16th to endDay
10%5%15%5%37%5%6%8%39%
1980
October1st to 15thDay
6%32432445%6%55%
1980
16th to endDay
6%213313335%64%
1947
November1st to 15thDay
11%5%35%4235%46%47%
1907
16th to endDay
11%424423345%55%
1755
December1st to 15thDay
22%8%34323236%39%
1621
16th to endDay
16%6%24423435%45%
1728
January1st to 15thNight
19%5%2332324448%
2327
16th to endNight
14%424324345%50%
2333
February1st to 15thNight
11%413313447%53%
2102
16th to endNight
10%313313346%58%
1894
March1st to 15thNight
13%423313346%53%
2010
16th to endNight
7%41442335%7%54%
2112
April1st to 15thNight
6%31332445%10%53%
1977
16th to endNight
7%43442445%8%50%
1824
May1st to 15thNight
5%3143245%6%11%49%
1619
16th to endNight
421342447%10%54%
1683
June1st to 15thNight
1111112449%70%
1620
16th to endNight
332232436%10%57%
1620
July1st to 15thNight
5%21232345%10%58%
1620
16th to endNight
41231435%9%62%
1702
August1st to 15thNight
11111235%9%70%
1797
16th to endNight
331442436%9%55%
1967
September1st to 15thNight
6%42442446%9%49%
1980
16th to endNight
9%5%1433446%8%48%
1980
October1st to 15thNight
5%213223246%65%
1980
16th to endNight
5%312212335%68%
2265
November1st to 15thNight
8%424423347%54%
2280
16th to endNight
8%312312345%62%
2534
December1st to 15thNight
19%423312335%48%
2353
16th to endNight
16%5%24213345%50%
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
42%36%14%17%14%
1612
16th to endDay
37%46%18%19%13%
1901
February1st to 15thDay
37%46%13%20%18%
1751
16th to endDay
31%37%19%24%12%
1580
March1st to 15thDay
39%47%15%19%14%
1949
16th to endDay
32%411%17%18%15%
2112
April1st to 15thDay
30%5%11%18%19%14%
1971
16th to endDay
36%48%19%16%14%
2130
May1st to 15thDay
37%7%9%18%16%9%
2331
16th to endDay
35%8%11%18%21%4
2434
June1st to 15thDay
23%7%12%25%23%6%
2340
16th to endDay
35%9%14%22%15%1
2340
July1st to 15thDay
36%7%14%23%16%1
2201
16th to endDay
29%7%18%34%9%
2309
August1st to 15thDay
21%7%15%35%18%
2147
16th to endDay
37%9%16%24%10%1
2232
September1st to 15thDay
41%9%14%18%13%2
1980
16th to endDay
40%8%12%16%13%7%
1980
October1st to 15thDay
28%6%11%19%26%8%
1980
16th to endDay
22%47%17%27%21%
1947
November1st to 15thDay
37%5%8%17%20%10%
1907
16th to endDay
31%5%6%18%19%18%
1755
December1st to 15thDay
48%36%14%16%10%
1621
16th to endDay
41%47%17%17%11%
1728
January1st to 15thNight
39%46%14%18%16%
2327
16th to endNight
35%5%7%17%19%15%
2333
February1st to 15thNight
31%48%15%16%22%
2112
16th to endNight
28%47%20%23%15%
1894
March1st to 15thNight
32%410%16%18%16%
2010
16th to endNight
29%6%12%18%18%13%
2112
April1st to 15thNight
26%413%20%20%14%
1977
16th to endNight
31%6%11%20%17%12%
1824
May1st to 15thNight
27%7%16%22%14%11%
1620
16th to endNight
23%8%16%28%19%3
1685
June1st to 15thNight
12%5%18%32%27%4
1620
16th to endNight
22%8%18%29%19%1
1620
July1st to 15thNight
21%7%24%32%13%
1530
16th to endNight
16%8%27%37%9%
1594
August1st to 15thNight
11%5%23%46%12%
1787
16th to endNight
23%9%23%33%8%1
1967
September1st to 15thNight
30%8%18%23%15%3
1980
16th to endNight
33%8%14%22%14%6%
1980
October1st to 15thNight
20%5%13%28%21%10%
1980
16th to endNight
20%37%19%26%23%
2265
November1st to 15thNight
30%5%12%20%21%10%
2280
16th to endNight
24%48%21%19%21%
2534
December1st to 15thNight
39%5%7%17%17%12%
2353
16th to endNight
37%38%16%19%14%
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
15%5%34%31%12%1
90
16th to endDay
17%10%33%20%16%1
96
February1st to 15thDay
10%8%33%26%15%5%
90
16th to endDay
7%7%39%40%31
81
March1st to 15thDay
26%6%24%27%12%2
90
16th to endDay
11%5%33%41%8%
96
April1st to 15thDay
10%8%30%44%6%
90
16th to endDay
7%11%42%29%7%
240
May1st to 15thDay
11%7%46%30%4
468
16th to endDay
9%433%40%12%
517
June1st to 15thDay
2110%55%27%3
495
16th to endDay
5%112%42%30%7%
495
July1st to 15thDay
5%114%41%33%4
475
16th to endDay
4439%43%7%
513
August1st to 15thDay
1442%35%14%
315
16th to endDay
9%18%40%26%13%
272
September1st to 15thDay
6%226%48%15%
135
16th to endDay
9%1217%42%25%
135
October1st to 15thDay
5%2424%36%27%
135
16th to endDay
9%213%33%32%8%
144
November1st to 15thDay
17%217%33%24%4
135
16th to endDay
11%7%22%34%16%7%
135
December1st to 15thDay
41%312%15%23%4
90
16th to endDay
20%10%29%26%12%1
96
January1st to 15thNight
20%427%36%9%
900
16th to endNight
17%6%29%38%8%
797
February1st to 15thNight
14%7%35%34%7%
704
16th to endNight
13%7%45%30%3
632
March1st to 15thNight
16%6%42%29%4
570
16th to endNight
9%7%52%28%1
576
April1st to 15thNight
7%5%61%21%3
539
16th to endNight
7%7%51%28%4
540
May1st to 15thNight
6%6%58%26%2
540
16th to endNight
6%444%39%6%
563
June1st to 15thNight
128%57%11%
540
16th to endNight
426%53%14%1
540
July1st to 15thNight
5%114%60%19%
510
16th to endNight
39%63%22%
564
August1st to 15thNight
29%63%22%2
539
16th to endNight
5%9%54%28%1
573
September1st to 15thNight
8%8%42%34%5%
540
16th to endNight
14%10%37%31%5%
537
October1st to 15thNight
5%15%47%28%2
540
16th to endNight
6%323%45%20%
729
November1st to 15thNight
9%225%43%17%1
760
16th to endNight
9%423%41%19%1
974
December1st to 15thNight
23%420%37%12%1
905
16th to endNight
20%5%26%35%12%
960
Page generated at 2017-12-02 08:14:15. Version ac04

Copyright 2017 A. Danko


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