Lucerne Valley
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lucerne Valley 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
70%
15963
37%
46800
29%
15923
77%
15923
61%
20663

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
62%
716
32%
2327
27%
716
72%
716
47%
1091
January16th to endNight
60%
768
36%
2340
28%
768
71%
768
46%
1154
February1st to 15thNight
62%
699
35%
2108
31%
698
71%
698
51%
993
February16th to endNight
54%
632
34%
1895
30%
632
65%
632
45%
951
March1st to 15thNight
57%
720
33%
2160
26%
720
69%
720
51%
990
March16th to endNight
57%
768
35%
2036
23%
768
68%
768
55%
1009
April1st to 15thNight
49%
719
36%
1799
14%
719
62%
719
57%
889
April16th to endNight
56%
720
39%
1800
16%
720
67%
720
69%
824
May1st to 15thNight
61%
555
39%
1634
23%
554
69%
554
71%
642
May16th to endNight
57%
561
36%
1685
21%
561
68%
561
69%
658
June1st to 15thNight
71%
540
35%
1620
27%
540
76%
540
79%
610
June16th to endNight
79%
418
41%
1498
40%
418
85%
418
83%
476
July1st to 15thNight
91%
412
34%
1432
35%
412
91%
412
69%
523
July16th to endNight
87%
582
33%
1610
27%
548
88%
548
63%
720
August1st to 15thNight
91%
717
38%
1790
24%
713
92%
713
81%
797
August16th to endNight
91%
764
43%
1910
29%
764
92%
764
78%
870
September1st to 15thNight
91%
720
42%
1866
32%
720
93%
720
78%
824
September16th to endNight
86%
680
49%
1881
42%
680
92%
680
87%
735
October1st to 15thNight
73%
660
43%
1815
35%
660
81%
660
72%
785
October16th to endNight
79%
704
44%
2143
41%
704
87%
704
66%
877
November1st to 15thNight
76%
700
37%
2275
37%
700
84%
700
61%
929
November16th to endNight
73%
720
39%
2340
39%
720
80%
720
58%
984
December1st to 15thNight
63%
720
34%
2340
29%
720
72%
720
46%
1100
December16th to endNight
56%
768
33%
2496
28%
768
66%
768
41%
1232

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
111212346%73%
48043
Night
11212246%75%
46997
TransparencyDay
13%36%15%27%33%
47737
Night
11%37%17%29%30%
46805
SeeingDay
413%29%34%14%4
5877
Night
16%18%32%31%8%
15974

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
121321335%8%66%
1611
16th to endDay
111333335%9%63%
1884
February1st to 15thDay
1221335%8%67%
1751
16th to endDay
12132245%5%8%63%
1579
March1st to 15thDay
111221245%10%67%
1800
16th to endDay
121345%9%69%
2184
April1st to 15thDay
112223347%70%
2149
16th to endDay
1111137%79%
2160
May1st to 15thDay
1112236%78%
2316
16th to endDay
11112136%80%
2429
June1st to 15thDay
11135%83%
2340
16th to endDay
11112287%
2454
July1st to 15thDay
212213346%71%
2433
16th to endDay
111233446%8%63%
2446
August1st to 15thDay
11112345%77%
2160
16th to endDay
112222346%72%
2292
September1st to 15thDay
21213345%74%
2092
16th to endDay
121122482%
1871
October1st to 15thDay
1113246%76%
1815
16th to endDay
1111235%81%
1725
November1st to 15thDay
11213345%75%
1584
16th to endDay
111213337%71%
1620
December1st to 15thDay
111232346%11%62%
1620
16th to endDay
221243435%8%62%
1728
January1st to 15thNight
121221345%9%64%
2327
16th to endNight
121231435%7%65%
2340
February1st to 15thNight
1212213348%67%
2101
16th to endNight
1222245%6%8%63%
1895
March1st to 15thNight
1131335%10%67%
2160
16th to endNight
112212349%70%
2036
April1st to 15thNight
113112347%73%
1799
16th to endNight
111246%80%
1800
May1st to 15thNight
111236%82%
1634
16th to endNight
111125%84%
1684
June1st to 15thNight
111487%
1620
16th to endNight
11290%
1498
July1st to 15thNight
111213480%
1518
16th to endNight
111131233475%
1719
August1st to 15thNight
1112484%
1800
16th to endNight
1112484%
1910
September1st to 15thNight
11122482%
1866
16th to endNight
112390%
1881
October1st to 15thNight
212237%78%
1815
16th to endNight
111223481%
2143
November1st to 15thNight
1212246%77%
2275
16th to endNight
112212337%73%
2340
December1st to 15thNight
121222345%9%64%
2340
16th to endNight
121322445%7%64%
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
17%49%19%31%17%
1612
16th to endDay
19%5%9%21%24%19%
1884
February1st to 15thDay
16%39%21%25%23%
1751
16th to endDay
20%5%9%19%30%14%
1579
March1st to 15thDay
13%47%24%29%20%
1800
16th to endDay
14%5%9%23%29%17%
2184
April1st to 15thDay
16%36%18%36%18%
2149
16th to endDay
8%37%21%33%25%
2160
May1st to 15thDay
8%36%18%32%30%
2316
16th to endDay
9%25%15%39%27%
2432
June1st to 15thDay
5%1411%25%51%
2340
16th to endDay
6%11412%72%
2454
July1st to 15thDay
14%35%9%16%50%
2291
16th to endDay
19%5%6%15%19%33%
2292
August1st to 15thDay
9%35%10%16%53%
2146
16th to endDay
13%35%8%25%43%
2292
September1st to 15thDay
12%46%7%26%43%
2092
16th to endDay
8%138%30%47%
1871
October1st to 15thDay
11%26%14%31%34%
1815
16th to endDay
8%2413%31%38%
1725
November1st to 15thDay
12%26%18%33%25%
1584
16th to endDay
14%46%19%28%25%
1620
December1st to 15thDay
17%5%10%22%24%18%
1620
16th to endDay
21%7%9%25%21%15%
1728
January1st to 15thNight
17%5%8%20%25%21%
2327
16th to endNight
20%411%17%24%22%
2340
February1st to 15thNight
16%410%19%25%22%
2112
16th to endNight
18%6%10%20%28%15%
1895
March1st to 15thNight
13%5%10%22%26%21%
2160
16th to endNight
13%410%24%31%15%
2036
April1st to 15thNight
12%38%24%32%17%
1799
16th to endNight
6%38%23%37%20%
1800
May1st to 15thNight
5%27%21%39%23%
1635
16th to endNight
6%27%21%40%22%
1685
June1st to 15thNight
5%1414%25%49%
1620
16th to endNight
4126%18%67%
1498
July1st to 15thNight
8%2310%19%55%
1432
16th to endNight
13%29%13%26%34%
1610
August1st to 15thNight
6%2310%25%51%
1790
16th to endNight
7%1310%29%46%
1910
September1st to 15thNight
7%15%10%26%48%
1866
16th to endNight
31210%35%47%
1881
October1st to 15thNight
8%26%14%34%33%
1815
16th to endNight
9%25%10%34%38%
2143
November1st to 15thNight
11%36%15%36%27%
2275
16th to endNight
13%38%20%29%25%
2340
December1st to 15thNight
18%410%18%27%19%
2340
16th to endNight
20%6%12%21%24%15%
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
7%20%31%31%8%1
90
16th to endDay
8%21%30%30%6%2
252
February1st to 15thDay
325%28%28%12%2
266
16th to endDay
10%26%30%24%8%
238
March1st to 15thDay
9%19%32%25%11%1
270
16th to endDay
7%21%34%24%10%
288
April1st to 15thDay
10%24%36%16%8%2
269
16th to endDay
8%30%31%23%41
270
May1st to 15thDay
319%34%30%7%4
288
16th to endDay
217%35%31%8%4
330
June1st to 15thDay
212%34%34%11%4
315
16th to endDay
339%35%13%6%
315
July1st to 15thDay
319%46%21%8%
305
16th to endDay
1218%44%21%11%
327
August1st to 15thDay
1323%42%19%8%
315
16th to endDay
219%45%22%9%
332
September1st to 15thDay
2326%46%18%2
315
16th to endDay
36%26%40%20%2
276
October1st to 15thDay
215%33%35%12%
255
16th to endDay
5%9%29%34%21%
195
November1st to 15thDay
45%21%27%27%13%
90
16th to endDay
6%13%31%31%17%
90
December1st to 15thDay
213%30%31%22%1
90
16th to endDay
10%17%23%36%11%
96
January1st to 15thNight
46%21%34%24%9%
720
16th to endNight
48%23%33%24%6%
768
February1st to 15thNight
47%21%35%23%7%
704
16th to endNight
311%27%29%21%5%
632
March1st to 15thNight
29%27%32%22%5%
720
16th to endNight
111%25%31%23%5%
768
April1st to 15thNight
214%32%25%19%5%
719
16th to endNight
112%28%28%22%6%
720
May1st to 15thNight
18%27%38%19%4
555
16th to endNight
10%28%29%26%3
563
June1st to 15thNight
423%44%24%2
540
16th to endNight
19%46%29%3
418
July1st to 15thNight
337%51%7%
412
16th to endNight
1436%50%7%
582
August1st to 15thNight
15%28%50%14%
717
16th to endNight
424%51%18%
764
September1st to 15thNight
428%47%17%
720
16th to endNight
110%29%42%15%
680
October1st to 15thNight
320%33%32%9%
660
16th to endNight
1411%32%33%16%
704
November1st to 15thNight
415%33%33%11%
700
16th to endNight
2416%32%30%12%
720
December1st to 15thNight
37%22%32%27%6%
720
16th to endNight
411%24%31%21%5%
768
Page generated at 2017-09-22 04:35:29. Version ac04

Copyright 2017 A. Danko


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