Twentynine Palms Airport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Twentynine Palms Airport clear sky chart from 2005-11-06 to 2024-01-17.

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%
24718
41%
74447
32%
24672
83%
24672
65%
31560

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 10thNight
67%
759
37%
2457
31%
756
78%
756
52%
1085
January11th to 20thNight
70%
748
40%
2430
34%
748
82%
748
56%
1042
January21st to endNight
58%
792
43%
2399
29%
792
75%
792
52%
1133
February1st to 10thNight
66%
720
41%
2160
32%
720
79%
720
57%
971
February11th to 20thNight
61%
700
41%
2098
31%
700
77%
700
58%
948
February21st to endNight
57%
592
41%
1776
34%
592
72%
592
57%
787
March1st to 10thNight
59%
720
36%
2160
28%
720
73%
720
55%
982
March11th to 20thNight
64%
720
40%
2018
29%
720
77%
720
62%
917
March21st to endNight
60%
792
41%
2160
24%
792
75%
792
63%
983
April1st to 10thNight
60%
720
41%
1800
20%
720
72%
720
63%
879
April11th to 20thNight
62%
711
43%
1779
20%
711
73%
711
71%
820
April21st to endNight
68%
680
46%
1760
23%
680
79%
680
80%
742
May1st to 10thNight
69%
540
46%
1620
30%
540
77%
540
77%
612
May11th to 20thNight
73%
531
45%
1595
31%
531
80%
531
80%
598
May21st to endNight
73%
583
42%
1746
30%
582
79%
582
80%
641
June1st to 10thNight
81%
540
38%
1620
32%
540
84%
540
81%
605
June11th to 20thNight
81%
540
40%
1620
33%
540
84%
540
84%
594
June21st to endNight
83%
540
38%
1620
32%
540
85%
540
78%
619
July1st to 10thNight
93%
525
37%
1575
33%
525
93%
525
79%
610
July11th to 20thNight
90%
522
37%
1566
32%
522
90%
522
66%
671
July21st to endNight
86%
591
36%
1674
31%
558
87%
558
57%
776
August1st to 10thNight
89%
655
38%
1720
25%
652
91%
652
72%
781
August11th to 20thNight
94%
712
41%
1780
28%
712
95%
712
79%
812
August21st to endNight
93%
792
45%
1980
32%
792
93%
792
76%
918
September1st to 10thNight
90%
720
41%
1865
33%
720
91%
720
76%
844
September11th to 20thNight
92%
720
49%
1980
43%
720
95%
720
86%
785
September21st to endNight
87%
720
48%
1980
40%
720
93%
720
83%
804
October1st to 10thNight
78%
720
45%
1980
36%
720
86%
720
73%
856
October11th to 20thNight
83%
720
51%
1980
43%
720
90%
720
81%
810
October21st to endNight
81%
792
46%
2480
43%
792
89%
792
78%
906
November1st to 10thNight
77%
740
43%
2405
38%
740
89%
740
72%
902
November11th to 20thNight
80%
760
44%
2470
43%
760
89%
760
69%
953
November21st to endNight
70%
760
41%
2470
39%
760
80%
760
59%
1034
December1st to 10thNight
70%
760
39%
2470
34%
760
80%
760
53%
1104
December11th to 20thNight
66%
758
37%
2891
31%
758
77%
758
43%
1296
December21st to endNight
60%
823
25%
4363
32%
817
73%
817
34%
1740

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
2112212346%77%
74906
Night
1112212346%77%
74961
TransparencyDay
11%3413%26%44%
74633
Night
11%3413%28%42%
74756
SeeingDay
38%19%34%27%10%
14368
Night
2417%38%34%6%
24739

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 10thDay
221332345%6%68%
1708
11th to 20thDay
4212212346%73%
1674
21st to endDay
2213325%446%69%
1953
February1st to 10thDay
2212213336%74%
1800
11th to 20thDay
1113223447%72%
1750
21st to endDay
1212223446%73%
1480
March1st to 10thDay
22222336%8%71%
1800
11th to 20thDay
2212312347%74%
1940
21st to endDay
1112113436%77%
2193
April1st to 10thDay
1212312347%74%
2160
11th to 20thDay
1111112235%82%
2129
21st to endDay
11111122485%
2200
May1st to 10thDay
111122236%82%
2340
11th to 20thDay
1111212487%
2301
21st to endDay
11111222485%
2530
June1st to 10thDay
11111225%86%
2340
11th to 20thDay
11112390%
2340
21st to endDay
211211221384%
2340
July1st to 10thDay
2111212335%78%
2340
11th to 20thDay
221221235%6%74%
2340
21st to endDay
33135%25%5%6%8%61%
2545
August1st to 10thDay
2212213345%76%
2205
11th to 20thDay
211122245%5%75%
2122
21st to endDay
2111212346%76%
2376
September1st to 10thDay
111323445%75%
2093
11th to 20thDay
111122390%
1980
21st to endDay
11121223484%
1980
October1st to 10thDay
1111222335%79%
1980
11th to 20thDay
1111112387%
1980
21st to endDay
1121222485%
1868
November1st to 10thDay
111212335%82%
1674
11th to 20thDay
1112222347%76%
1710
21st to endDay
211221335%6%75%
1710
December1st to 10thDay
2313333448%66%
1710
11th to 20thDay
231242445%11%60%
2169
21st to endDay
5%3123235%6%8%60%
3146
January1st to 10thNight
221232345%8%67%
2457
11th to 20thNight
121222435%7%71%
2430
21st to endNight
3213423345%70%
2399
February1st to 10thNight
2212313435%73%
2160
11th to 20thNight
321222335%7%71%
2098
21st to endNight
1212214346%73%
1776
March1st to 10thNight
211232336%7%70%
2160
11th to 20thNight
2212212347%74%
2018
21st to endNight
1112213348%75%
2160
April1st to 10thNight
1112223446%75%
1800
11th to 20thNight
111121223483%
1779
21st to endNight
1111237%83%
1760
May1st to 10thNight
1111226%86%
1620
11th to 20thNight
11211225%86%
1594
21st to endNight
111112489%
1746
June1st to 10thNight
11122487%
1620
11th to 20thNight
1111111390%
1620
21st to endNight
11121212387%
1620
July1st to 10thNight
1111222485%
1620
11th to 20thNight
1113223346%75%
1620
21st to endNight
331232445%6%68%
1773
August1st to 10thNight
221112345%79%
1729
11th to 20thNight
111112245%81%
1780
21st to endNight
11121223482%
1980
September1st to 10thNight
1112211335%81%
1865
11th to 20thNight
111112291%
1980
21st to endNight
1111122388%
1980
October1st to 10thNight
111122223481%
1980
11th to 20thNight
11111112388%
1980
21st to endNight
1111235%85%
2480
November1st to 10thNight
11112235%83%
2405
11th to 20thNight
1111113336%79%
2470
21st to endNight
221222335%6%74%
2470
December1st to 10thNight
321222345%8%68%
2470
11th to 20thNight
221232446%10%63%
3041
21st to endNight
32133245%6%8%63%
4521

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 10thDay
17%46%20%36%17%
1709
11th to 20thDay
15%35%19%34%23%
1674
21st to endDay
17%36%18%32%24%
1953
February1st to 10thDay
15%25%15%30%33%
1800
11th to 20thDay
13%3415%29%35%
1760
21st to endDay
13%46%16%31%31%
1480
March1st to 10thDay
12%35%16%32%31%
1800
11th to 20thDay
11%35%16%32%32%
1940
21st to endDay
9%3319%37%28%
2193
April1st to 10thDay
13%3314%32%34%
2160
11th to 20thDay
7%2210%31%48%
2132
21st to endDay
6%1212%32%46%
2200
May1st to 10thDay
7%2211%29%48%
2340
11th to 20thDay
5%218%28%56%
2304
21st to endDay
6%229%28%53%
2530
June1st to 10thDay
6%127%22%62%
2340
11th to 20thDay
3115%14%76%
2340
21st to endDay
9%1129%77%
2340
July1st to 10thDay
10%326%14%65%
2276
11th to 20thDay
11%4412%24%44%
2271
21st to endDay
19%5%7%15%22%32%
2404
August1st to 10thDay
11%348%21%53%
2190
11th to 20thDay
10%3411%23%48%
2122
21st to endDay
10%3310%22%53%
2376
September1st to 10thDay
11%4410%15%57%
2093
11th to 20thDay
4116%19%69%
1980
21st to endDay
7%226%23%60%
1980
October1st to 10thDay
9%339%25%52%
1980
11th to 20thDay
5%238%25%58%
1980
21st to endDay
8%129%22%57%
1868
November1st to 10thDay
8%3313%31%43%
1674
11th to 20thDay
10%3313%29%42%
1710
21st to endDay
12%2416%32%35%
1710
December1st to 10thDay
19%35%20%25%27%
1710
11th to 20thDay
19%6%11%23%26%15%
2168
21st to endDay
21%5%9%26%26%14%
3146
January1st to 10thNight
15%5%6%20%33%22%
2457
11th to 20thNight
14%36%18%32%26%
2430
21st to endNight
18%35%19%26%28%
2399
February1st to 10thNight
15%2415%28%36%
2160
11th to 20thNight
15%2414%30%34%
2099
21st to endNight
13%35%15%32%32%
1776
March1st to 10thNight
14%45%18%31%28%
2160
11th to 20thNight
11%3416%33%32%
2018
21st to endNight
10%35%17%36%28%
2160
April1st to 10thNight
12%3417%33%32%
1800
11th to 20thNight
8%2312%31%44%
1779
21st to endNight
42411%33%46%
1760
May1st to 10thNight
5%2214%33%44%
1620
11th to 20thNight
5%1310%30%51%
1595
21st to endNight
32212%37%44%
1746
June1st to 10thNight
4128%24%60%
1620
11th to 20thNight
4115%14%74%
1620
21st to endNight
7%11411%77%
1620
July1st to 10thNight
6%225%16%69%
1575
11th to 20thNight
11%3411%25%45%
1566
21st to endNight
15%46%17%25%32%
1674
August1st to 10thNight
9%339%20%56%
1720
11th to 20thNight
6%3310%25%52%
1780
21st to endNight
8%229%23%56%
1980
September1st to 10thNight
8%348%19%58%
1865
11th to 20thNight
4125%20%68%
1980
21st to endNight
5%217%20%64%
1980
October1st to 10thNight
9%239%29%48%
1980
11th to 20thNight
6%126%26%59%
1980
21st to endNight
5%239%20%60%
2480
November1st to 10thNight
8%239%34%44%
2405
11th to 20thNight
9%2311%30%44%
2470
21st to endNight
13%3413%32%35%
2470
December1st to 10thNight
16%45%18%25%31%
2470
11th to 20thNight
18%6%9%17%32%20%
3041
21st to endNight
18%6%9%24%28%14%
4521

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 10thDay
6%10%26%34%20%4
270
11th to 20thDay
8%8%18%41%21%4
258
21st to endDay
7%12%28%31%17%4
435
February1st to 10thDay
6%10%26%32%21%5%
420
11th to 20thDay
6%18%28%33%14%2
415
21st to endDay
7%18%29%29%16%1
346
March1st to 10thDay
6%19%25%34%15%1
420
11th to 20thDay
5%14%25%35%16%5%
420
21st to endDay
5%19%29%31%14%2
462
April1st to 10thDay
6%14%20%30%21%8%
420
11th to 20thDay
317%28%28%19%5%
412
21st to endDay
315%25%29%20%9%
420
May1st to 10thDay
211%22%36%24%5%
423
11th to 20thDay
29%23%34%25%8%
448
21st to endDay
19%23%34%25%8%
485
June1st to 10thDay
26%17%34%30%11%
450
11th to 20thDay
420%29%33%14%
450
21st to endDay
3217%38%27%14%
450
July1st to 10thDay
19%36%32%21%
446
11th to 20thDay
27%33%35%23%
444
21st to endDay
217%36%32%23%
487
August1st to 10thDay
2111%34%36%17%
447
11th to 20thDay
218%31%34%24%
437
21st to endDay
27%30%39%21%
495
September1st to 10thDay
2112%38%33%14%
450
11th to 20thDay
414%36%35%11%
450
21st to endDay
25%17%31%34%12%
450
October1st to 10thDay
18%20%32%34%6%
450
11th to 20thDay
1418%38%33%7%
450
21st to endDay
25%17%31%34%11%
311
November1st to 10thDay
25%17%36%34%7%
270
11th to 20thDay
26%20%33%31%8%
270
21st to endDay
27%24%34%24%9%
270
December1st to 10thDay
45%17%46%23%4
270
11th to 20thDay
48%20%36%28%4
270
21st to endDay
7%10%29%32%18%3
297
January1st to 10thNight
36%21%40%25%6%
760
11th to 20thNight
25%20%43%24%6%
748
21st to endNight
4427%38%22%4
792
February1st to 10thNight
35%22%40%25%6%
720
11th to 20thNight
36%26%39%22%5%
704
21st to endNight
28%30%38%18%4
592
March1st to 10thNight
37%27%39%21%3
720
11th to 20thNight
28%23%34%25%8%
720
21st to endNight
19%27%37%22%4
792
April1st to 10thNight
28%25%38%24%3
720
11th to 20thNight
28%26%37%23%4
711
21st to endNight
17%23%39%26%5%
680
May1st to 10thNight
15%23%38%31%2
540
11th to 20thNight
1419%37%35%4
531
21st to endNight
16%19%40%30%3
584
June1st to 10thNight
313%46%35%2
540
11th to 20thNight
1116%45%36%2
540
21st to endNight
1113%39%41%4
540
July1st to 10thNight
1337%51%7%
525
11th to 20thNight
2433%56%6%
522
21st to endNight
21432%56%7%
591
August1st to 10thNight
25%32%50%10%
655
11th to 20thNight
1122%64%12%
712
21st to endNight
1323%57%15%
792
September1st to 10thNight
115%28%55%10%
720
11th to 20thNight
15%40%45%9%
720
21st to endNight
110%36%44%9%
720
October1st to 10thNight
1216%40%37%3
720
11th to 20thNight
2212%41%37%8%
720
21st to endNight
1413%37%35%11%
792
November1st to 10thNight
1217%37%33%10%
740
11th to 20thNight
2313%40%34%9%
760
21st to endNight
3419%42%25%7%
760
December1st to 10thNight
4220%45%24%5%
760
11th to 20thNight
4421%43%25%4
760
21st to endNight
5%7%23%40%20%5%
836
Page generated at 2024-01-14 06:55:04. Version ac07

Copyright 2024 Attilla Danko


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