Lone Palm Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lone Palm Observatory clear sky chart from 2005-11-06 to 2024-01-12.

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
60%
24732
18%
74492
15%
24678
64%
24678
27%
48065

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
46%
758
22%
2459
16%
757
56%
757
28%
1453
January11th to 20thNight
50%
728
25%
2365
19%
728
61%
728
29%
1406
January21st to endNight
41%
792
22%
2574
15%
792
51%
792
26%
1603
February1st to 10thNight
48%
720
22%
2164
16%
720
55%
720
30%
1319
February11th to 20thNight
50%
700
24%
2071
15%
699
60%
699
38%
1179
February21st to endNight
53%
592
28%
1628
19%
592
60%
592
40%
944
March1st to 10thNight
52%
720
29%
1980
19%
720
60%
720
43%
1100
March11th to 20thNight
58%
720
27%
1980
20%
720
64%
720
42%
1124
March21st to endNight
56%
792
27%
2178
18%
792
64%
792
39%
1284
April1st to 10thNight
58%
720
24%
1980
19%
720
62%
720
43%
1109
April11th to 20thNight
58%
711
20%
1865
14%
711
61%
711
34%
1192
April21st to endNight
63%
720
25%
1800
15%
720
66%
720
41%
1092
May1st to 10thNight
68%
720
24%
1800
17%
720
70%
720
46%
1050
May11th to 20thNight
67%
531
15%
1592
11%
531
69%
531
29%
1024
May21st to endNight
71%
582
18%
1744
14%
582
72%
582
28%
1140
June1st to 10thNight
63%
540
11%
1620
9%
540
64%
540
19%
1185
June11th to 20thNight
72%
540
14%
1620
12%
540
73%
540
24%
1124
June21st to endNight
73%
540
10%
1620
9%
540
73%
540
23%
1138
July1st to 10thNight
74%
525
5%
1575
5%
525
74%
525
18%
1171
July11th to 20thNight
74%
522
7%
1566
6%
522
74%
522
21%
1115
July21st to endNight
76%
591
9%
1672
8%
558
76%
558
22%
1167
August1st to 10thNight
78%
537
8%
1600
7%
534
78%
534
25%
1087
August11th to 20thNight
75%
636
6%
1700
5%
636
75%
636
25%
1207
August21st to endNight
65%
792
7%
2119
7%
792
65%
792
19%
1613
September1st to 10thNight
67%
720
7%
1980
7%
720
67%
720
17%
1493
September11th to 20thNight
64%
720
5%
1980
5%
720
64%
720
17%
1512
September21st to endNight
61%
720
13%
1980
13%
720
61%
720
19%
1488
October1st to 10thNight
59%
720
17%
2052
18%
720
61%
720
23%
1398
October11th to 20thNight
66%
720
23%
2160
23%
720
70%
720
28%
1358
October21st to endNight
60%
792
23%
2376
22%
792
65%
792
31%
1438
November1st to 10thNight
55%
740
21%
2221
18%
740
61%
740
28%
1428
November11th to 20thNight
55%
760
24%
2280
21%
760
61%
760
28%
1456
November21st to endNight
53%
760
23%
2280
20%
760
58%
760
26%
1488
December1st to 10thNight
60%
760
26%
2465
22%
760
68%
760
31%
1420
December11th to 20thNight
53%
759
19%
2970
19%
758
58%
758
22%
1845
December21st to endNight
52%
832
14%
4476
19%
817
58%
817
15%
2915

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%5%36%7%47%7%8%10%36%
74894
Night
8%5%36%6%45%6%7%9%42%
74829
TransparencyDay
38%11%17%17%13%4
74617
Night
36%10%17%20%13%5%
74625
SeeingDay
8%418%28%25%18%
14602
Night
8%317%31%30%9%
24744

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 10thDay
12%5%25%6%35%5%6%8%44%
1706
11th to 20thDay
6%5%35%4445%7%11%47%
1635
21st to endDay
12%5%37%445%5%5%8%43%
1782
February1st to 10thDay
11%6%25%6%35%6%5%8%43%
1792
11th to 20thDay
6%425%5%35%5%6%7%52%
1772
21st to endDay
9%5%25%5%45%5%6%8%47%
1628
March1st to 10thDay
5%425%5%35%5%6%10%51%
1980
11th to 20thDay
7%3245%35%6%8%8%48%
1980
21st to endDay
7%4245%35%6%6%9%50%
2178
April1st to 10thDay
5%4245%45%6%7%10%48%
1980
11th to 20thDay
8%436%6%47%7%8%9%39%
2044
21st to endDay
6%326%6%45%5%7%9%48%
2160
May1st to 10thDay
5%413435%5%7%9%54%
2172
11th to 20thDay
8%6%37%6%47%6%7%8%38%
2301
21st to endDay
8%6%36%7%5%8%8%8%9%33%
2531
June1st to 10thDay
14%7%38%7%5%8%7%8%11%23%
2340
11th to 20thDay
6%427%8%5%8%10%9%11%28%
2340
21st to endDay
8%5%37%8%5%8%8%10%11%25%
2340
July1st to 10thDay
9%6%37%8%5%9%8%9%11%25%
2340
11th to 20thDay
9%6%37%9%5%8%7%9%12%25%
2340
21st to endDay
8%5%38%8%6%8%9%9%12%24%
2547
August1st to 10thDay
6%426%7%6%9%9%11%13%27%
2327
11th to 20thDay
6%5%37%9%5%9%9%10%13%25%
2178
21st to endDay
10%7%38%9%5%6%8%9%11%24%
2231
September1st to 10thDay
7%6%37%9%5%9%8%9%11%25%
1980
11th to 20thDay
9%6%38%8%5%7%9%9%11%24%
1980
21st to endDay
9%7%38%8%6%7%8%8%9%25%
1980
October1st to 10thDay
10%7%37%7%5%7%7%7%10%29%
1906
11th to 20thDay
7%5%35%7%46%7%8%9%40%
1800
21st to endDay
9%425%5%45%5%7%10%44%
1980
November1st to 10thDay
8%435%7%45%6%8%9%40%
1857
11th to 20thDay
10%6%36%6%45%7%7%9%39%
1900
21st to endDay
9%5%36%7%36%6%6%9%39%
1900
December1st to 10thDay
8%436%5%45%5%6%8%44%
1710
11th to 20thDay
11%7%36%6%45%5%6%8%40%
2153
21st to endDay
11%6%47%7%5%8%7%7%8%32%
3124
January1st to 10thNight
10%5%25%5%345%5%8%47%
2459
11th to 20thNight
8%6%25%445%5%6%9%46%
2365
21st to endNight
11%6%35%5%446%6%6%44%
2574
February1st to 10thNight
10%6%35%5%3445%8%46%
2164
11th to 20thNight
9%3244345%6%7%53%
2071
21st to endNight
7%4244345%7%7%53%
1628
March1st to 10thNight
5%2245%2446%7%58%
1980
11th to 20thNight
8%32442446%9%54%
1980
21st to endNight
5%4245%35%5%7%8%53%
2178
April1st to 10thNight
6%224335%46%8%56%
1980
11th to 20thNight
5%435%6%35%6%7%9%47%
1865
21st to endNight
6%325%5%35%5%6%8%53%
1800
May1st to 10thNight
6%31342446%8%59%
1800
11th to 20thNight
7%426%6%45%6%8%10%43%
1592
21st to endNight
7%5%35%5%46%7%8%12%38%
1744
June1st to 10thNight
11%7%37%7%38%8%8%11%28%
1620
11th to 20thNight
7%5%27%6%47%7%8%14%33%
1620
21st to endNight
6%5%27%8%37%6%8%12%35%
1620
July1st to 10thNight
8%6%36%7%48%7%9%12%31%
1620
11th to 20thNight
7%5%36%7%5%7%7%8%11%33%
1620
21st to endNight
5%5%36%6%5%7%7%8%12%35%
1771
August1st to 10thNight
5%426%5%37%6%10%13%36%
1611
11th to 20thNight
5%426%7%5%7%8%10%12%34%
1700
21st to endNight
9%7%46%8%5%7%8%7%12%28%
2119
September1st to 10thNight
6%5%37%8%48%8%9%13%29%
1980
11th to 20thNight
8%7%38%8%5%7%7%8%11%27%
1980
21st to endNight
11%7%48%7%5%5%7%8%9%30%
1980
October1st to 10thNight
11%6%37%5%45%6%7%11%36%
2052
11th to 20thNight
7%5%37%5%35%5%6%8%45%
2160
21st to endNight
9%6%26%4345%6%9%46%
2376
November1st to 10thNight
9%436%6%45%6%6%7%44%
2221
11th to 20thNight
8%5%36%6%45%5%7%9%42%
2280
21st to endNight
11%5%26%6%36%6%7%9%40%
2280
December1st to 10thNight
5%4247%45%6%6%9%48%
2465
11th to 20thNight
14%7%35%43445%8%42%
3042
21st to endNight
12%7%38%7%46%5%6%8%35%
4532

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
36%7%11%20%19%7%
1707
11th to 20thDay
30%7%9%26%22%6%
1635
21st to endDay
40%5%9%17%21%9%
1782
February1st to 10thDay
38%6%11%16%21%8%
1792
11th to 20thDay
29%5%13%23%22%8%
1782
21st to endDay
33%6%13%16%26%6%
1628
March1st to 10thDay
27%7%14%24%21%7%
1980
11th to 20thDay
30%7%15%26%17%6%
1980
21st to endDay
28%9%11%24%22%7%
2178
April1st to 10thDay
28%9%16%25%17%5%
1980
11th to 20thDay
37%10%13%19%18%4
2044
21st to endDay
29%7%13%22%23%5%
2160
May1st to 10thDay
24%7%14%23%24%7%
2172
11th to 20thDay
39%10%15%21%14%1
2305
21st to endDay
41%13%14%18%14%1
2531
June1st to 10thDay
50%13%19%14%4
2340
11th to 20thDay
42%15%22%20%2
2340
21st to endDay
43%15%24%13%3
2340
July1st to 10thDay
44%17%27%10%1
2275
11th to 20thDay
43%17%27%12%1
2271
21st to endDay
43%18%23%14%1
2405
August1st to 10thDay
36%19%33%11%1
2314
11th to 20thDay
40%19%30%10%1
2178
21st to endDay
46%18%23%10%3
2231
September1st to 10thDay
43%20%22%12%3
1980
11th to 20thDay
45%18%22%12%3
1980
21st to endDay
48%15%14%12%10%1
1980
October1st to 10thDay
45%12%13%15%11%4
1906
11th to 20thDay
38%10%9%20%20%3
1800
21st to endDay
33%6%13%19%21%7%
1980
November1st to 10thDay
35%8%15%17%18%7%
1857
11th to 20thDay
39%8%10%21%16%6%
1900
21st to endDay
39%8%12%19%18%5%
1900
December1st to 10thDay
35%8%14%24%14%4
1710
11th to 20thDay
39%7%11%17%17%8%
2150
21st to endDay
46%8%12%15%12%6%
3124
January1st to 10thNight
35%6%13%21%18%7%
2459
11th to 20thNight
34%7%10%25%18%6%
2365
21st to endNight
38%6%11%21%15%9%
2574
February1st to 10thNight
36%6%14%18%18%9%
2164
11th to 20thNight
29%5%13%23%21%9%
2072
21st to endNight
27%7%15%21%24%6%
1628
March1st to 10thNight
24%6%13%28%21%7%
1980
11th to 20thNight
26%6%17%29%16%7%
1980
21st to endNight
27%8%12%25%20%7%
2178
April1st to 10thNight
24%7%19%26%16%7%
1980
11th to 20thNight
31%10%14%22%19%4
1865
21st to endNight
29%6%15%23%22%6%
1800
May1st to 10thNight
23%8%13%26%22%8%
1800
11th to 20thNight
34%11%18%24%11%2
1593
21st to endNight
35%11%18%19%15%1
1745
June1st to 10thNight
46%12%21%16%4
1620
11th to 20thNight
39%13%21%23%4
1620
21st to endNight
39%14%25%17%4
1620
July1st to 10thNight
43%18%26%13%1
1575
11th to 20thNight
40%16%29%14%1
1566
21st to endNight
35%19%30%15%1
1672
August1st to 10thNight
34%17%35%14%
1600
11th to 20thNight
35%18%34%12%1
1700
21st to endNight
46%15%24%12%2
2119
September1st to 10thNight
42%20%22%14%2
1980
11th to 20thNight
46%17%22%14%2
1980
21st to endNight
48%13%16%14%8%2
1980
October1st to 10thNight
41%10%16%19%10%3
2052
11th to 20thNight
36%8%11%23%18%3
2160
21st to endNight
34%8%13%18%19%8%
2376
November1st to 10thNight
38%8%13%16%19%7%
2221
11th to 20thNight
37%9%12%22%13%7%
2280
21st to endNight
39%8%12%19%18%4
2280
December1st to 10thNight
32%7%15%29%11%5%
2465
11th to 20thNight
41%6%13%16%14%10%
3044
21st to endNight
46%8%13%16%12%5%
4532

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
13%7%42%24%11%3
270
11th to 20thDay
49%38%29%16%4
245
21st to endDay
13%13%45%22%7%
264
February1st to 10thDay
11%10%34%29%13%3
240
11th to 20thDay
6%6%31%38%14%5%
264
21st to endDay
8%6%28%35%20%3
346
March1st to 10thDay
6%8%33%37%14%2
420
11th to 20thDay
9%5%30%32%20%3
420
21st to endDay
5%5%28%35%23%4
462
April1st to 10thDay
6%7%31%34%17%5%
420
11th to 20thDay
7%9%25%33%21%5%
412
21st to endDay
6%5%21%34%25%9%
420
May1st to 10thDay
5%221%35%26%10%
423
11th to 20thDay
9%314%30%28%16%
447
21st to endDay
8%311%25%30%23%
485
June1st to 10thDay
14%28%26%29%21%
450
11th to 20thDay
6%16%24%31%33%
450
21st to endDay
5%15%16%30%42%
450
July1st to 10thDay
6%1311%30%50%
445
11th to 20thDay
5%139%37%45%
444
21st to endDay
7%16%18%28%40%
488
August1st to 10thDay
41415%35%41%
446
11th to 20thDay
41314%31%47%
439
21st to endDay
9%15%20%30%34%
495
September1st to 10thDay
8%3417%30%38%
450
11th to 20thDay
9%18%25%27%30%
450
21st to endDay
9%18%23%35%24%
450
October1st to 10thDay
13%216%35%25%9%
450
11th to 20thDay
7%217%36%30%8%
450
21st to endDay
8%319%36%26%7%
495
November1st to 10thDay
9%7%19%36%21%8%
455
11th to 20thDay
10%6%27%32%22%4
460
21st to endDay
8%424%40%21%3
460
December1st to 10thDay
5%7%28%39%16%4
270
11th to 20thDay
8%9%27%36%16%4
270
21st to endDay
8%7%26%38%18%3
297
January1st to 10thNight
13%7%27%35%16%2
760
11th to 20thNight
9%6%28%38%16%2
728
21st to endNight
12%7%32%36%11%
792
February1st to 10thNight
11%8%24%39%17%1
720
11th to 20thNight
10%6%30%37%16%2
703
21st to endNight
9%428%44%16%
592
March1st to 10thNight
46%33%42%14%1
720
11th to 20thNight
6%5%27%40%20%2
720
21st to endNight
5%429%41%21%1
792
April1st to 10thNight
5%6%26%42%20%1
720
11th to 20thNight
6%5%24%41%22%1
711
21st to endNight
6%222%45%22%3
720
May1st to 10thNight
6%216%47%26%2
720
11th to 20thNight
9%211%34%38%6%
531
21st to endNight
8%17%28%46%10%
584
June1st to 10thNight
11%17%26%44%10%
540
11th to 20thNight
7%1419%45%24%
540
21st to endNight
6%1414%47%29%
540
July1st to 10thNight
7%2312%49%27%
525
11th to 20thNight
7%1210%44%36%
522
21st to endNight
5%1310%49%33%
591
August1st to 10thNight
4211%50%31%
537
11th to 20thNight
41310%48%34%
636
21st to endNight
11%16%18%40%24%
792
September1st to 10thNight
7%25%17%45%24%
720
11th to 20thNight
10%25%21%44%18%
720
21st to endNight
12%36%22%41%16%
720
October1st to 10thNight
14%113%31%35%6%
720
11th to 20thNight
7%312%32%39%7%
720
21st to endNight
11%218%33%32%5%
792
November1st to 10thNight
9%321%34%28%5%
740
11th to 20thNight
8%424%37%24%3
760
21st to endNight
12%422%42%19%2
760
December1st to 10thNight
5%423%38%28%3
760
11th to 20thNight
11%6%23%34%23%3
760
21st to endNight
10%5%25%37%21%2
836
Page generated at 2024-01-09 16:24:25. Version ac07

Copyright 2024 Attilla Danko


Lone Palm Observatory Clear Sky Chart |Charts Home