Anderson Mesa Station
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Anderson Mesa Station clear sky chart from 2005-11-06 to 2025-06-10.

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
53%
25524
33%
112479
21%
25158
66%
25158
38%
44739

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
45%
787
39%
5571
22%
756
64%
756
26%
1901
January11th to 20thNight
44%
786
30%
5405
23%
760
60%
760
36%
1405
January21st to endNight
39%
868
33%
5857
20%
836
58%
836
21%
2375
February1st to 10thNight
42%
800
32%
2595
19%
800
62%
800
43%
1174
February11th to 20thNight
38%
780
33%
2339
19%
780
56%
780
44%
1113
February21st to endNight
38%
660
36%
1960
22%
660
56%
660
43%
926
March1st to 10thNight
34%
792
40%
4226
15%
764
54%
764
32%
1375
March11th to 20thNight
44%
791
24%
4391
18%
760
59%
760
25%
1960
March21st to endNight
38%
864
27%
4574
12%
836
57%
836
28%
1823
April1st to 10thNight
38%
800
31%
2200
11%
800
54%
800
46%
1080
April11th to 20thNight
35%
632
35%
2016
15%
632
56%
632
44%
874
April21st to endNight
43%
600
43%
1810
20%
600
65%
600
53%
766
May1st to 10thNight
44%
582
37%
3453
19%
569
60%
569
30%
1275
May11th to 20thNight
48%
575
30%
3229
22%
551
62%
551
41%
956
May21st to endNight
45%
629
23%
3725
19%
604
59%
604
47%
926
June1st to 10thNight
55%
599
33%
1795
23%
599
63%
599
60%
783
June11th to 20thNight
55%
570
36%
1710
26%
570
64%
570
68%
675
June21st to endNight
65%
570
31%
1710
24%
570
71%
570
60%
757
July1st to 10thNight
74%
541
35%
2371
21%
535
77%
535
44%
869
July11th to 20thNight
78%
540
15%
2497
16%
533
80%
533
22%
1504
July21st to endNight
72%
610
17%
2580
16%
569
74%
569
23%
1332
August1st to 10thNight
77%
557
17%
2753
20%
545
79%
545
21%
1623
August11th to 20thNight
78%
546
23%
2412
23%
543
80%
543
37%
978
August21st to endNight
80%
643
27%
2982
29%
636
82%
636
35%
1312
September1st to 10thNight
75%
760
30%
2090
24%
760
78%
760
49%
1107
September11th to 20thNight
73%
760
40%
2090
29%
760
80%
760
64%
971
September21st to endNight
68%
760
38%
2090
24%
760
78%
760
60%
969
October1st to 10thNight
57%
740
48%
3206
21%
740
70%
740
48%
1137
October11th to 20thNight
61%
748
31%
3361
27%
740
73%
740
46%
1244
October21st to endNight
55%
822
45%
3779
27%
813
71%
813
50%
1197
November1st to 10thNight
55%
780
41%
2340
25%
780
71%
780
54%
1060
November11th to 20thNight
57%
800
38%
2590
26%
800
73%
800
56%
1044
November21st to endNight
47%
800
37%
2600
25%
800
63%
800
43%
1192
December1st to 10thNight
50%
784
46%
3879
24%
780
64%
780
39%
1295
December11th to 20thNight
45%
784
24%
4370
22%
778
60%
778
30%
1610
December21st to endNight
40%
864
31%
5923
20%
839
56%
839
22%
2151

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
2315%44445%7%61%
124075
Night
131433435%7%66%
123140
TransparencyDay
20%5%8%17%28%22%
123843
Night
16%5%9%18%31%22%
122960
SeeingDay
9%17%28%27%15%4
15653
Night
5%12%25%33%21%4
25832

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
1227%445%345%64%
4098
11th to 20thDay
1213233235%73%
4100
21st to endDay
35%26%44335%7%58%
4510
February1st to 10thDay
1425%43426%8%61%
1804
11th to 20thDay
142444446%7%61%
1950
21st to endDay
3245%5%5%46%7%59%
1668
March1st to 10thDay
15%1434336%7%62%
4954
11th to 20thDay
29%37%5%45%46%7%48%
5000
21st to endDay
121334446%8%63%
5486
April1st to 10thDay
13245%4435%7%62%
2200
11th to 20thDay
1325%333346%69%
2331
21st to endDay
141433235%6%68%
2586
May1st to 10thDay
2425%334245%66%
5880
11th to 20thDay
131434435%7%65%
5841
21st to endDay
1213233345%73%
6423
June1st to 10thDay
1213324246%71%
2589
11th to 20thDay
111211223482%
2470
21st to endDay
121334445%5%66%
2470
July1st to 10thDay
2214345%35%6%65%
4110
11th to 20thDay
3326%8%9%9%7%10%10%32%
4110
21st to endDay
3427%6%7%8%6%9%9%38%
4454
August1st to 10thDay
35%29%8%8%8%6%8%8%32%
4092
11th to 20thDay
2316%5%7%6%6%8%9%47%
4028
21st to endDay
3426%5%6%7%5%6%8%49%
4258
September1st to 10thDay
3426%5%6%6%6%7%7%48%
2090
11th to 20thDay
231333445%5%67%
2090
21st to endDay
221332335%7%68%
2090
October1st to 10thDay
2425%33334467%
3371
11th to 20thDay
2415%333235%70%
3150
21st to endDay
1112222245%79%
3438
November1st to 10thDay
1212333247%72%
1959
11th to 20thDay
113323445%74%
1806
21st to endDay
2423333246%67%
1800
December1st to 10thDay
1214323345%71%
2950
11th to 20thDay
1325%43337%12%56%
3409
21st to endDay
2426%44446%8%57%
4510
January1st to 10thNight
225%34445%7%65%
5867
11th to 20thNight
121222325%7%74%
5880
21st to endNight
25%25%34445%6%59%
6468
February1st to 10thNight
31444436%6%65%
2595
11th to 20thNight
1213435%5%6%7%64%
2338
21st to endNight
131334437%9%63%
1960
March1st to 10thNight
131335%435%8%65%
4940
11th to 20thNight
27%35%45%6%5%6%8%49%
5000
21st to endNight
131434337%8%63%
5489
April1st to 10thNight
31333335%6%69%
2200
11th to 20thNight
1214333346%70%
2016
21st to endNight
111222346%77%
1810
May1st to 10thNight
121434435%6%68%
4100
11th to 20thNight
1112222235%78%
4074
21st to endNight
11111235%6%79%
4474
June1st to 10thNight
1213223345%74%
1795
11th to 20thNight
111221212385%
1710
21st to endNight
1214323346%72%
1710
July1st to 10thNight
121223335%7%70%
2860
11th to 20thNight
2316%7%7%9%8%10%11%38%
2860
21st to endNight
332445%6%5%8%10%50%
3109
August1st to 10thNight
2438%6%6%7%6%9%11%38%
2847
11th to 20thNight
111323447%12%61%
2811
21st to endNight
1214445%5%7%10%58%
3406
September1st to 10thNight
2324345%47%9%57%
2090
11th to 20thNight
2212223245%76%
2090
21st to endNight
1212222246%74%
2090
October1st to 10thNight
121222325%6%74%
3604
11th to 20thNight
2313223236%73%
3778
21st to endNight
121322225%6%75%
4120
November1st to 10thNight
121322335%6%71%
2340
11th to 20thNight
113223345%75%
2590
21st to endNight
2213443346%67%
2600
December1st to 10thNight
121333335%9%70%
4240
11th to 20thNight
131433445%7%64%
4811
21st to endNight
231444435%5%65%
6468

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
20%5%8%23%34%11%
4099
11th to 20thDay
13%5%8%21%22%31%
4100
21st to endDay
21%6%7%15%30%21%
4510
February1st to 10thDay
21%5%9%19%27%19%
1804
11th to 20thDay
19%6%9%23%26%18%
1960
21st to endDay
20%5%10%19%26%20%
1668
March1st to 10thDay
16%48%18%34%20%
4954
11th to 20thDay
26%7%10%21%26%10%
5000
21st to endDay
14%5%10%32%30%9%
5486
April1st to 10thDay
19%47%19%35%16%
2200
11th to 20thDay
16%36%16%35%23%
2334
21st to endDay
16%37%17%39%18%
2586
May1st to 10thDay
19%36%16%38%18%
5880
11th to 20thDay
14%5%8%11%34%28%
5844
21st to endDay
12%248%30%43%
6424
June1st to 10thDay
12%46%12%32%34%
2589
11th to 20thDay
8%137%27%53%
2470
21st to endDay
17%5%6%10%26%36%
2470
July1st to 10thDay
17%5%7%11%10%50%
4046
11th to 20thDay
35%11%13%18%15%8%
4041
21st to endDay
32%13%15%15%20%6%
4314
August1st to 10thDay
41%11%17%13%9%10%
4078
11th to 20thDay
26%11%12%19%17%15%
4067
21st to endDay
30%7%12%19%22%11%
4257
September1st to 10thDay
29%8%10%13%17%22%
2090
11th to 20thDay
17%5%9%13%31%25%
2090
21st to endDay
15%47%15%33%26%
2090
October1st to 10thDay
19%35%11%21%40%
3371
11th to 20thDay
17%27%9%44%22%
3150
21st to endDay
10%2415%36%32%
3438
November1st to 10thDay
13%36%25%33%20%
1959
11th to 20thDay
11%47%18%37%23%
1806
21st to endDay
18%37%19%35%19%
1800
December1st to 10thDay
15%36%23%33%19%
2950
11th to 20thDay
21%48%22%37%9%
3408
21st to endDay
22%5%9%25%30%9%
4510
January1st to 10thNight
17%6%8%22%37%11%
5867
11th to 20thNight
10%49%22%29%26%
5880
21st to endNight
21%6%7%13%28%24%
6468
February1st to 10thNight
16%5%10%21%28%20%
2595
11th to 20thNight
15%6%10%23%28%18%
2339
21st to endNight
15%6%10%18%29%22%
1960
March1st to 10thNight
11%410%20%37%18%
4940
11th to 20thNight
22%5%11%22%29%11%
5000
21st to endNight
14%7%9%29%30%10%
5489
April1st to 10thNight
15%5%8%19%35%18%
2200
11th to 20thNight
14%36%14%37%25%
2016
21st to endNight
10%46%20%42%19%
1810
May1st to 10thNight
16%48%18%35%20%
4097
11th to 20thNight
9%36%12%38%32%
4075
21st to endNight
8%148%37%43%
4474
June1st to 10thNight
12%4410%32%39%
1795
11th to 20thNight
8%135%28%54%
1710
21st to endNight
14%35%9%25%44%
1710
July1st to 10thNight
13%5%8%12%12%51%
2815
11th to 20thNight
31%10%14%22%14%9%
2806
21st to endNight
25%9%18%20%19%10%
3011
August1st to 10thNight
35%9%19%15%10%11%
2838
11th to 20thNight
16%6%19%23%23%13%
2838
21st to endNight
20%5%13%19%32%11%
3406
September1st to 10thNight
20%6%13%17%22%21%
2090
11th to 20thNight
11%5%5%18%31%30%
2090
21st to endNight
11%47%13%34%31%
2090
October1st to 10thNight
12%36%12%24%42%
3604
11th to 20thNight
14%25%13%45%21%
3778
21st to endNight
10%35%13%37%34%
4120
November1st to 10thNight
14%45%22%35%21%
2340
11th to 20thNight
10%37%17%38%24%
2590
21st to endNight
18%48%17%31%22%
2600
December1st to 10thNight
13%38%22%32%22%
4240
11th to 20thNight
17%5%7%19%38%14%
4811
21st to endNight
19%5%8%24%29%15%
6468

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
11%22%35%20%11%1
300
11th to 20thDay
11%23%28%26%10%3
300
21st to endDay
8%22%29%24%14%2
330
February1st to 10thDay
16%21%29%22%11%1
304
11th to 20thDay
15%28%29%23%4
495
21st to endDay
16%28%34%17%4
414
March1st to 10thDay
19%28%29%17%6%
500
11th to 20thDay
16%26%28%20%9%2
500
21st to endDay
16%30%31%17%5%1
550
April1st to 10thDay
10%25%34%19%10%2
500
11th to 20thDay
16%28%33%15%7%2
492
21st to endDay
10%31%29%20%9%2
500
May1st to 10thDay
9%24%39%20%7%1
503
11th to 20thDay
9%20%33%24%10%3
528
21st to endDay
9%21%32%25%10%3
573
June1st to 10thDay
315%35%30%14%3
527
11th to 20thDay
6%17%36%25%13%4
490
21st to endDay
311%35%35%14%3
490
July1st to 10thDay
5%432%32%23%5%
486
11th to 20thDay
7%215%39%26%11%
484
21st to endDay
9%214%33%31%11%
531
August1st to 10thDay
6%316%39%25%11%
487
11th to 20thDay
5%317%41%26%7%
477
21st to endDay
5%418%35%27%10%
539
September1st to 10thDay
7%6%19%34%26%9%
490
11th to 20thDay
5%11%31%30%18%5%
490
21st to endDay
8%11%23%33%20%5%
490
October1st to 10thDay
6%19%26%25%18%6%
423
11th to 20thDay
8%13%27%29%19%4
300
21st to endDay
9%18%25%25%18%4
330
November1st to 10thDay
13%18%24%31%13%2
300
11th to 20thDay
7%18%27%25%21%3
300
21st to endDay
12%19%27%26%15%3
300
December1st to 10thDay
8%20%28%25%17%1
300
11th to 20thDay
6%18%30%28%14%3
300
21st to endDay
16%20%28%28%6%2
330
January1st to 10thNight
6%15%30%28%16%6%
800
11th to 20thNight
7%14%30%29%16%4
800
21st to endNight
7%18%31%29%12%3
880
February1st to 10thNight
6%18%31%30%12%3
800
11th to 20thNight
5%22%32%28%12%2
784
21st to endNight
8%20%31%28%10%2
660
March1st to 10thNight
8%24%31%27%9%1
800
11th to 20thNight
7%17%28%30%15%3
800
21st to endNight
7%18%33%30%11%1
880
April1st to 10thNight
420%33%30%11%1
800
11th to 20thNight
7%19%35%29%8%2
632
21st to endNight
421%30%30%13%3
600
May1st to 10thNight
416%32%37%11%1
600
11th to 20thNight
412%30%33%19%2
591
21st to endNight
414%33%33%14%2
650
June1st to 10thNight
18%33%43%14%1
599
11th to 20thNight
29%30%42%15%2
570
21st to endNight
3424%45%24%1
570
July1st to 10thNight
414%45%34%3
555
11th to 20thNight
38%40%43%5%
552
21st to endNight
6%17%33%45%7%
624
August1st to 10thNight
419%35%43%8%
567
11th to 20thNight
417%39%42%7%
564
21st to endNight
317%36%45%9%
658
September1st to 10thNight
3311%31%44%8%
760
11th to 20thNight
3416%38%33%6%
760
21st to endNight
39%16%32%33%7%
760
October1st to 10thNight
5%7%26%36%23%3
760
11th to 20thNight
6%7%23%39%21%6%
760
21st to endNight
312%25%30%21%8%
836
November1st to 10thNight
412%26%36%18%5%
780
11th to 20thNight
214%24%36%19%6%
800
21st to endNight
6%16%27%29%17%5%
800
December1st to 10thNight
6%15%24%32%20%2
800
11th to 20thNight
7%15%28%31%18%2
800
21st to endNight
8%16%31%31%10%4
880
Page generated at 2025-06-07 07:28:19. Version ac07

Copyright © 2025 Attilla Danko.


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