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Landers
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Landers clear sky chart from 2005-11-05 to 2019-05-11.

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
74%
18386
40%
53676
31%
18347
82%
18347
66%
23043

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
68%
838
35%
2717
29%
836
78%
836
48%
1251
January16th to endNight
63%
896
39%
2758
30%
896
76%
896
52%
1280
February1st to 15thNight
64%
819
40%
2468
31%
818
78%
818
58%
1106
February16th to endNight
60%
736
38%
2207
34%
736
71%
736
55%
1016
March1st to 15thNight
62%
840
37%
2499
30%
840
75%
840
58%
1108
March16th to endNight
66%
896
39%
2416
26%
896
77%
896
63%
1119
April1st to 15thNight
56%
839
40%
2099
17%
839
70%
839
62%
1035
April16th to endNight
63%
820
41%
2068
20%
820
73%
820
72%
925
May1st to 15thNight
71%
616
45%
1849
30%
616
78%
616
78%
699
May16th to endNight
70%
609
39%
1829
27%
609
76%
609
78%
697
June1st to 15thNight
80%
585
37%
1755
29%
585
84%
585
82%
652
June16th to endNight
84%
585
37%
1755
31%
585
86%
585
83%
656
July1st to 15thNight
90%
555
33%
1665
30%
555
90%
555
72%
673
July16th to endNight
90%
612
35%
1737
29%
579
91%
579
62%
773
August1st to 15thNight
93%
748
39%
1894
26%
745
94%
745
80%
847
August16th to endNight
92%
828
43%
2070
30%
828
93%
828
80%
938
September1st to 15thNight
92%
780
43%
2044
35%
780
93%
780
79%
888
September16th to endNight
88%
776
49%
2145
43%
776
93%
776
87%
836
October1st to 15thNight
78%
780
46%
2145
36%
780
86%
780
76%
903
October16th to endNight
82%
832
45%
2519
42%
832
89%
832
73%
991
November1st to 15thNight
78%
820
42%
2665
39%
820
88%
820
69%
1023
November16th to endNight
76%
840
42%
2730
40%
840
84%
840
62%
1114
December1st to 15thNight
69%
840
38%
2730
32%
840
80%
840
52%
1217
December16th to endNight
61%
896
37%
2912
30%
896
74%
896
49%
1296

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
111112235%76%
54176
Night
111112235%78%
53875
TransparencyDay
11%25%14%27%38%
53871
Night
10%25%14%29%37%
53681
SeeingDay
310%23%34%21%5%
8012
Night
1416%33%34%9%
18396

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
321221225%6%68%
1881
16th to endDay
1212313346%68%
2168
February1st to 15thDay
1112113347%71%
2051
16th to endDay
112214346%70%
1839
March1st to 15thDay
11111235%7%72%
2120
16th to endDay
12112247%74%
2509
April1st to 15thDay
1111212236%75%
2509
16th to endDay
1111136%82%
2495
May1st to 15thDay
1111123481%
2658
16th to endDay
1222483%
2637
June1st to 15thDay
112485%
2535
16th to endDay
11111289%
2535
July1st to 15thDay
212212245%72%
2535
16th to endDay
21232445%6%66%
2675
August1st to 15thDay
111121224476%
2307
16th to endDay
11112346%75%
2484
September1st to 15thDay
1121223379%
2244
16th to endDay
11111287%
2145
October1st to 15thDay
111222481%
2145
16th to endDay
11113483%
2054
November1st to 15thDay
1111223478%
1854
16th to endDay
111113246%74%
1890
December1st to 15thDay
2212222239%67%
1890
16th to endDay
2212222337%68%
2016
January1st to 15thNight
122223447%67%
2717
16th to endNight
21221235%6%70%
2758
February1st to 15thNight
212212335%73%
2461
16th to endNight
22121246%7%68%
2207
March1st to 15thNight
211212348%71%
2499
16th to endNight
2212246%76%
2416
April1st to 15thNight
11212335%76%
2099
16th to endNight
11226%82%
2068
May1st to 15thNight
1225%84%
1849
16th to endNight
212485%
1828
June1st to 15thNight
112387%
1755
16th to endNight
111290%
1755
July1st to 15thNight
11112235%78%
1755
16th to endNight
112123345%73%
1845
August1st to 15thNight
1111135%82%
1903
16th to endNight
1111135%82%
2070
September1st to 15thNight
11113483%
2044
16th to endNight
1291%
2145
October1st to 15thNight
111225%83%
2145
16th to endNight
111122483%
2519
November1st to 15thNight
112235%80%
2665
16th to endNight
211111235%76%
2730
December1st to 15thNight
222223338%68%
2730
16th to endNight
222212247%70%
2912

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
17%47%19%31%19%
1882
16th to endDay
17%45%21%29%21%
2168
February1st to 15thDay
14%45%17%31%26%
2051
16th to endDay
14%5%7%18%33%19%
1839
March1st to 15thDay
11%35%20%32%25%
2120
16th to endDay
11%26%22%32%23%
2509
April1st to 15thDay
13%25%16%35%27%
2509
16th to endDay
6%1416%34%36%
2495
May1st to 15thDay
8%1311%34%40%
2658
16th to endDay
7%1411%32%42%
2640
June1st to 15thDay
5%128%18%63%
2535
16th to endDay
6%139%78%
2535
July1st to 15thDay
13%35%9%17%51%
2396
16th to endDay
16%5%7%16%21%33%
2520
August1st to 15thDay
10%239%21%51%
2292
16th to endDay
10%3411%24%46%
2484
September1st to 15thDay
10%348%20%52%
2244
16th to endDay
6%115%27%57%
2145
October1st to 15thDay
9%2310%29%44%
2145
16th to endDay
7%149%29%47%
2054
November1st to 15thDay
11%25%14%33%33%
1854
16th to endDay
11%35%16%32%29%
1890
December1st to 15thDay
17%38%22%26%22%
1890
16th to endDay
18%48%24%26%17%
2016
January1st to 15thNight
17%47%18%27%22%
2717
16th to endNight
15%47%20%26%24%
2758
February1st to 15thNight
14%26%18%29%27%
2472
16th to endNight
14%47%19%31%22%
2207
March1st to 15thNight
12%35%21%31%24%
2499
16th to endNight
10%36%18%38%22%
2416
April1st to 15thNight
11%45%18%33%26%
2099
16th to endNight
6%1314%37%36%
2068
May1st to 15thNight
5%1416%36%36%
1850
16th to endNight
5%1315%36%37%
1829
June1st to 15thNight
4129%18%62%
1755
16th to endNight
415%12%75%
1755
July1st to 15thNight
9%148%18%57%
1665
16th to endNight
11%45%17%25%34%
1737
August1st to 15thNight
6%2310%22%54%
1894
16th to endNight
6%239%28%49%
2070
September1st to 15thNight
6%25%9%20%56%
2044
16th to endNight
315%27%61%
2145
October1st to 15thNight
7%2411%33%41%
2145
16th to endNight
7%148%26%50%
2519
November1st to 15thNight
8%2413%37%33%
2665
16th to endNight
12%25%16%32%30%
2730
December1st to 15thNight
15%47%18%27%25%
2730
16th to endNight
16%310%19%29%20%
2912

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
11%6%22%35%20%3
180
16th to endDay
316%29%31%15%4
344
February1st to 15thDay
414%31%28%15%5%
386
16th to endDay
6%23%28%26%15%
342
March1st to 15thDay
5%21%26%30%14%1
390
16th to endDay
5%15%32%32%12%1
416
April1st to 15thDay
5%21%26%26%15%3
389
16th to endDay
324%28%24%14%4
378
May1st to 15thDay
312%28%36%13%5%
389
16th to endDay
19%32%35%15%4
394
June1st to 15thDay
16%25%36%24%5%
375
16th to endDay
1322%36%25%11%
375
July1st to 15thDay
113%42%30%12%
365
16th to endDay
313%40%28%13%
391
August1st to 15thDay
2116%43%25%10%
359
16th to endDay
1113%40%29%13%
396
September1st to 15thDay
1119%49%24%3
375
16th to endDay
27%21%36%29%3
375
October1st to 15thDay
210%27%40%16%1
375
16th to endDay
26%18%31%31%9%
286
November1st to 15thDay
18%18%33%32%5%
180
16th to endDay
29%25%27%29%6%
180
December1st to 15thDay
7%9%20%29%31%2
180
16th to endDay
7%12%18%29%26%5%
192
January1st to 15thNight
2420%37%24%10%
840
16th to endNight
35%23%33%28%6%
896
February1st to 15thNight
25%22%34%26%8%
824
16th to endNight
26%29%34%20%6%
736
March1st to 15thNight
27%25%33%25%6%
840
16th to endNight
17%21%36%26%7%
896
April1st to 15thNight
17%29%30%24%5%
839
16th to endNight
9%23%31%26%7%
820
May1st to 15thNight
1422%38%28%5%
617
16th to endNight
423%37%28%4
611
June1st to 15thNight
117%43%34%3
585
16th to endNight
12%41%40%4
585
July1st to 15thNight
1332%52%9%
555
16th to endNight
2232%54%7%
612
August1st to 15thNight
227%51%17%
748
16th to endNight
1220%51%23%
828
September1st to 15thNight
229%50%16%
780
16th to endNight
17%30%44%14%
776
October1st to 15thNight
1116%35%36%7%
780
16th to endNight
211%30%38%16%
832
November1st to 15thNight
116%34%36%10%
820
16th to endNight
3314%31%33%13%
840
December1st to 15thNight
3419%36%28%7%
840
16th to endNight
5%8%20%33%24%7%
896
Page generated at 2019-05-11 21:31:07. Version ac04

Copyright 2019 A. Danko


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