Desert Pines Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Desert Pines Observatory 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
72%
23995
36%
74359
31%
23944
78%
23944
53%
35153

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
64%
758
34%
2457
30%
756
73%
756
48%
1166
January11th to 20thNight
66%
748
37%
2430
33%
748
76%
748
50%
1135
January21st to endNight
61%
792
36%
2574
32%
792
71%
792
41%
1317
February1st to 10thNight
67%
720
37%
2295
35%
720
76%
720
52%
1062
February11th to 20thNight
61%
700
34%
2099
28%
700
71%
700
46%
1082
February21st to endNight
55%
592
39%
1691
29%
592
68%
592
51%
857
March1st to 10thNight
58%
720
37%
1980
27%
720
69%
720
53%
1008
March11th to 20thNight
67%
720
38%
1980
28%
720
75%
720
58%
973
March21st to endNight
67%
792
38%
2178
26%
792
76%
792
57%
1080
April1st to 10thNight
70%
720
38%
1980
27%
720
78%
720
66%
903
April11th to 20thNight
64%
575
42%
1819
33%
575
76%
575
63%
742
April21st to endNight
71%
540
47%
1769
39%
540
82%
540
72%
657
May1st to 10thNight
71%
540
43%
1620
32%
540
81%
540
70%
651
May11th to 20thNight
75%
531
42%
1594
36%
531
80%
531
69%
651
May21st to endNight
76%
582
44%
1746
36%
582
81%
582
80%
660
June1st to 10thNight
81%
540
37%
1620
32%
540
83%
540
68%
679
June11th to 20thNight
83%
540
40%
1620
33%
540
86%
540
78%
628
June21st to endNight
82%
540
31%
1620
26%
540
83%
540
58%
739
July1st to 10thNight
82%
525
24%
1575
21%
525
82%
525
45%
819
July11th to 20thNight
83%
522
21%
1566
19%
522
83%
522
38%
886
July21st to endNight
78%
591
17%
1674
14%
558
77%
558
30%
1037
August1st to 10thNight
86%
537
26%
1602
24%
534
86%
534
47%
830
August11th to 20thNight
80%
534
30%
1602
28%
534
80%
534
40%
875
August21st to endNight
86%
636
31%
2014
32%
636
86%
636
44%
1047
September1st to 10thNight
78%
720
32%
1980
28%
720
79%
720
46%
1108
September11th to 20thNight
83%
720
40%
1980
34%
720
84%
720
60%
968
September21st to endNight
77%
720
39%
1980
29%
720
83%
720
60%
957
October1st to 10thNight
76%
720
40%
2052
31%
720
82%
720
63%
957
October11th to 20thNight
79%
720
44%
2160
35%
720
86%
720
71%
883
October21st to endNight
77%
792
46%
2376
38%
792
84%
792
72%
973
November1st to 10thNight
74%
740
45%
2220
37%
740
80%
740
67%
946
November11th to 20thNight
74%
760
43%
2308
36%
760
82%
760
64%
996
November21st to endNight
63%
760
37%
2470
33%
760
71%
760
47%
1191
December1st to 10thNight
66%
760
38%
2470
35%
760
73%
760
50%
1154
December11th to 20thNight
61%
760
33%
2927
32%
758
71%
758
34%
1546
December21st to endNight
60%
828
23%
4331
32%
817
67%
817
28%
1990

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
431332345%6%66%
74994
Night
4313323446%66%
74869
TransparencyDay
19%35%12%24%37%
74721
Night
19%35%13%25%35%
74664
SeeingDay
6%7%23%34%24%7%
13790
Night
5%216%41%31%5%
24011

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
7%324324447%61%
1708
11th to 20thDay
6%323423446%66%
1674
21st to endDay
7%423323346%63%
1782
February1st to 10thDay
6%312323235%69%
1660
11th to 20thDay
9%414434445%59%
1750
21st to endDay
8%423322337%65%
1563
March1st to 10thDay
6%31332445%7%62%
1980
11th to 20thDay
6%313322345%67%
1980
21st to endDay
421332233473%
2178
April1st to 10thDay
2111213437%73%
1980
11th to 20thDay
2212211325%80%
2087
21st to endDay
211211223480%
2186
May1st to 10thDay
1111212335%79%
2340
11th to 20thDay
11222333478%
2301
21st to endDay
11111112387%
2530
June1st to 10thDay
3212212246%76%
2340
11th to 20thDay
11111223384%
2340
21st to endDay
221332346%6%68%
2340
July1st to 10thDay
3214446%7%7%8%53%
2340
11th to 20thDay
3336%6%46%8%10%11%40%
2340
21st to endDay
7%5%36%7%5%6%7%9%13%31%
2545
August1st to 10thDay
5%325%6%36%6%7%9%48%
2328
11th to 20thDay
3325%5%46%7%8%11%47%
2299
21st to endDay
32245%47%6%7%9%52%
2335
September1st to 10thDay
6%424435%46%7%56%
1980
11th to 20thDay
3213324445%71%
1980
21st to endDay
322323435%71%
1980
October1st to 10thDay
2112224347%72%
1907
11th to 20thDay
2111211235%81%
1800
21st to endDay
2111223345%77%
1980
November1st to 10thDay
221121225%7%76%
1859
11th to 20thDay
221222444473%
1867
21st to endDay
6%324423446%63%
1710
December1st to 10thDay
7%21343345%6%61%
1710
11th to 20thDay
8%6%25%42446%7%52%
2169
21st to endDay
8%425%423445%59%
3146
January1st to 10thNight
6%32332345%6%63%
2457
11th to 20thNight
6%323223345%67%
2430
21st to endNight
7%424424445%60%
2574
February1st to 10thNight
6%313313435%68%
2295
11th to 20thNight
8%413324446%61%
2098
21st to endNight
8%313323345%64%
1691
March1st to 10thNight
5%32233345%7%63%
1980
11th to 20thNight
6%223323335%70%
1980
21st to endNight
4322323346%68%
2178
April1st to 10thNight
2112223345%74%
1980
11th to 20thNight
221221223478%
1819
21st to endNight
31111113483%
1769
May1st to 10thNight
1111213245%79%
1620
11th to 20thNight
1112222235%79%
1594
21st to endNight
11111112388%
1746
June1st to 10thNight
2112122346%76%
1620
11th to 20thNight
1111112125%84%
1620
21st to endNight
1213323446%71%
1620
July1st to 10thNight
3314435%6%7%8%56%
1620
11th to 20thNight
22145%5%5%8%11%14%42%
1620
21st to endNight
3425%6%47%8%10%15%34%
1773
August1st to 10thNight
2214335%6%8%10%56%
1611
11th to 20thNight
3325%5%45%5%7%9%52%
1602
21st to endNight
3314445%6%9%11%51%
2014
September1st to 10thNight
5%3245%3446%9%55%
1980
11th to 20thNight
2213323336%71%
1980
21st to endNight
2212423445%70%
1980
October1st to 10thNight
2212323346%71%
2052
11th to 20thNight
211121233479%
2160
21st to endNight
211221223481%
2376
November1st to 10thNight
2212213335%75%
2220
11th to 20thNight
3212222336%74%
2308
21st to endNight
7%323423346%63%
2470
December1st to 10thNight
7%313223447%64%
2470
11th to 20thNight
8%5%25%5%34446%55%
3041
21st to endNight
9%5%244245%45%57%
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
24%3414%29%26%
1709
11th to 20thDay
21%25%10%29%33%
1674
21st to endDay
23%3216%27%29%
1782
February1st to 10thDay
20%2312%24%40%
1660
11th to 20thDay
27%2413%24%30%
1760
21st to endDay
22%1211%29%34%
1563
March1st to 10thDay
22%1310%30%33%
1980
11th to 20thDay
20%229%26%40%
1980
21st to endDay
17%239%33%37%
2178
April1st to 10thDay
12%226%34%44%
1980
11th to 20thDay
11%116%26%55%
2090
21st to endDay
10%127%26%54%
2186
May1st to 10thDay
10%127%20%59%
2340
11th to 20thDay
11%139%21%55%
2304
21st to endDay
7%11422%66%
2530
June1st to 10thDay
11%11422%60%
2340
11th to 20thDay
7%21216%73%
2340
21st to endDay
16%348%19%51%
2340
July1st to 10thDay
24%6%8%14%18%30%
2276
11th to 20thDay
32%7%18%22%14%7%
2271
21st to endDay
39%9%16%21%11%4
2404
August1st to 10thDay
29%5%11%17%19%18%
2313
11th to 20thDay
27%7%13%18%20%14%
2299
21st to endDay
27%7%9%21%20%17%
2335
September1st to 10thDay
26%46%19%20%24%
1980
11th to 20thDay
16%3312%25%40%
1980
21st to endDay
17%3310%29%39%
1980
October1st to 10thDay
13%25%14%27%39%
1907
11th to 20thDay
9%138%25%54%
1800
21st to endDay
12%239%26%49%
1980
November1st to 10thDay
10%1311%36%38%
1859
11th to 20thDay
15%2310%28%42%
1867
21st to endDay
23%2411%26%35%
1710
December1st to 10thDay
23%2416%27%27%
1710
11th to 20thDay
31%2418%24%21%
2168
21st to endDay
27%2417%32%19%
3146
January1st to 10thNight
22%2415%33%24%
2457
11th to 20thNight
20%2313%29%31%
2430
21st to endNight
26%3313%30%24%
2574
February1st to 10thNight
20%2313%22%39%
2295
11th to 20thNight
25%25%14%24%30%
2099
21st to endNight
22%2311%30%32%
1691
March1st to 10thNight
21%2312%27%35%
1980
11th to 20thNight
19%2211%24%43%
1980
21st to endNight
18%2312%32%32%
2178
April1st to 10thNight
13%229%33%41%
1980
11th to 20thNight
12%118%26%51%
1819
21st to endNight
9%116%29%54%
1769
May1st to 10thNight
10%138%24%54%
1620
11th to 20thNight
10%229%22%55%
1595
21st to endNight
6%115%23%65%
1746
June1st to 10thNight
11%216%22%58%
1620
11th to 20thNight
7%11215%73%
1620
21st to endNight
15%346%16%55%
1620
July1st to 10thNight
23%5%11%15%14%32%
1575
11th to 20thNight
26%9%18%25%15%7%
1566
21st to endNight
33%10%23%19%11%4
1674
August1st to 10thNight
20%7%14%22%18%20%
1602
11th to 20thNight
27%5%14%21%18%14%
1602
21st to endNight
22%6%12%22%20%17%
2014
September1st to 10thNight
25%5%8%22%18%22%
1980
11th to 20thNight
15%4413%27%37%
1980
21st to endNight
17%3311%29%38%
1980
October1st to 10thNight
15%25%15%24%39%
2052
11th to 20thNight
10%2210%25%51%
2160
21st to endNight
10%1210%27%50%
2376
November1st to 10thNight
13%1212%32%40%
2220
11th to 20thNight
14%1312%29%40%
2308
21st to endNight
23%2312%28%32%
2470
December1st to 10thNight
21%25%17%26%29%
2470
11th to 20thNight
31%2416%26%21%
3041
21st to endNight
29%3415%29%20%
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
10%6%28%38%17%
270
11th to 20thDay
11%231%36%16%4
258
21st to endDay
5%7%29%37%18%3
264
February1st to 10thDay
6%8%30%32%18%6%
280
11th to 20thDay
16%13%33%31%8%1
415
21st to endDay
13%15%39%25%7%1
346
March1st to 10thDay
10%15%35%28%9%3
420
11th to 20thDay
9%13%30%30%14%5%
420
21st to endDay
7%18%38%24%11%2
462
April1st to 10thDay
5%15%30%27%19%4
420
11th to 20thDay
6%17%32%30%13%2
412
21st to endDay
315%30%32%16%4
420
May1st to 10thDay
413%33%29%16%4
423
11th to 20thDay
29%30%38%17%4
448
21st to endDay
27%33%38%17%3
485
June1st to 10thDay
46%23%41%21%6%
450
11th to 20thDay
2422%43%23%5%
450
21st to endDay
3120%42%28%6%
450
July1st to 10thDay
319%38%40%10%
446
11th to 20thDay
326%34%40%17%
444
21st to endDay
6%26%25%43%18%
487
August1st to 10thDay
415%33%41%15%
447
11th to 20thDay
415%30%43%16%
437
21st to endDay
226%31%40%20%
495
September1st to 10thDay
7%313%36%33%8%
450
11th to 20thDay
2215%40%32%9%
450
21st to endDay
6%5%22%34%25%8%
450
October1st to 10thDay
26%24%35%26%7%
377
11th to 20thDay
3321%36%31%6%
270
21st to endDay
1423%33%30%9%
297
November1st to 10thDay
46%29%39%20%3
270
11th to 20thDay
4425%39%26%3
270
21st to endDay
7%8%26%39%17%2
270
December1st to 10thDay
8%429%33%24%2
270
11th to 20thDay
9%432%40%13%1
270
21st to endDay
13%9%32%26%16%3
297
January1st to 10thNight
8%121%44%22%3
760
11th to 20thNight
7%221%42%24%4
748
21st to endNight
10%220%45%20%3
792
February1st to 10thNight
7%219%43%23%6%
720
11th to 20thNight
9%421%47%17%2
704
21st to endNight
9%5%27%43%15%1
592
March1st to 10thNight
6%427%45%16%2
720
11th to 20thNight
7%319%39%25%6%
720
21st to endNight
4421%45%24%2
792
April1st to 10thNight
2320%52%21%2
720
11th to 20thNight
35%24%46%20%1
575
21st to endNight
3321%50%21%2
540
May1st to 10thNight
1421%49%23%2
540
11th to 20thNight
1218%49%27%2
531
21st to endNight
2218%49%28%1
584
June1st to 10thNight
2211%51%33%1
540
11th to 20thNight
2112%50%34%2
540
21st to endNight
119%41%44%3
540
July1st to 10thNight
215%33%54%4
525
11th to 20thNight
3322%64%8%
522
21st to endNight
41323%55%13%
591
August1st to 10thNight
31121%62%12%
537
11th to 20thNight
41424%60%7%
534
21st to endNight
31323%59%11%
636
September1st to 10thNight
6%16%29%48%10%
720
11th to 20thNight
27%38%43%8%
720
21st to endNight
3113%41%37%5%
720
October1st to 10thNight
3215%47%31%3
720
11th to 20thNight
2215%45%31%5%
720
21st to endNight
2115%43%30%9%
792
November1st to 10thNight
3117%44%30%5%
740
11th to 20thNight
3117%44%32%3
760
21st to endNight
8%321%43%21%4
760
December1st to 10thNight
10%119%42%25%4
760
11th to 20thNight
8%322%45%17%4
760
21st to endNight
10%320%43%19%5%
836
Page generated at 2024-01-14 07:55:04. Version ac07

Copyright 2024 Attilla Danko


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