Telescope Array Black Rock Mesa FD
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Telescope Array Black Rock Mesa FD clear sky chart from 2005-11-06 to 2024-03-08.

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
62%
24157
24%
80064
22%
24082
66%
24082
34%
44870

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
59%
747
14%
4047
16%
736
62%
736
14%
2530
January11th to 20thNight
57%
751
13%
4098
20%
740
61%
740
15%
2626
January21st to endNight
58%
824
13%
4445
19%
814
60%
814
15%
2717
February1st to 10thNight
56%
760
20%
2470
19%
760
61%
760
27%
1510
February11th to 20thNight
56%
740
21%
2245
19%
740
60%
740
31%
1363
February21st to endNight
53%
628
24%
1884
22%
628
59%
628
31%
1155
March1st to 10thNight
51%
750
22%
2150
19%
750
56%
750
31%
1334
March11th to 20thNight
60%
720
27%
1980
23%
720
64%
720
42%
1149
March21st to endNight
49%
792
23%
2178
13%
792
57%
792
34%
1337
April1st to 10thNight
52%
720
21%
1980
14%
720
56%
720
35%
1206
April11th to 20thNight
47%
575
27%
1643
18%
575
53%
575
35%
963
April21st to endNight
53%
540
28%
1620
17%
540
60%
540
39%
886
May1st to 10thNight
52%
540
23%
1620
17%
540
56%
540
32%
962
May11th to 20thNight
61%
531
26%
1595
20%
531
65%
531
43%
845
May21st to endNight
58%
582
23%
1746
19%
582
63%
582
37%
970
June1st to 10thNight
63%
540
27%
1620
22%
540
70%
540
50%
790
June11th to 20thNight
59%
540
29%
1620
22%
540
67%
540
53%
753
June21st to endNight
67%
540
28%
1620
24%
540
73%
540
60%
717
July1st to 10thNight
71%
525
24%
1575
21%
525
75%
525
50%
771
July11th to 20thNight
69%
522
21%
1566
18%
522
72%
522
38%
863
July21st to endNight
72%
591
24%
1674
21%
558
73%
558
38%
924
August1st to 10thNight
67%
537
29%
1602
21%
534
71%
534
44%
823
August11th to 20thNight
74%
534
34%
1602
25%
534
78%
534
51%
784
August21st to endNight
74%
634
36%
1822
28%
634
76%
634
51%
902
September1st to 10thNight
79%
720
35%
1975
26%
720
84%
720
62%
936
September11th to 20thNight
70%
720
37%
1980
26%
720
78%
720
59%
959
September21st to endNight
73%
720
38%
1980
30%
720
79%
720
60%
965
October1st to 10thNight
67%
720
32%
2016
24%
720
72%
720
49%
1064
October11th to 20thNight
74%
720
35%
2160
31%
720
79%
720
52%
1052
October21st to endNight
70%
792
37%
2394
31%
792
76%
792
53%
1149
November1st to 10thNight
67%
740
32%
2405
30%
740
71%
740
44%
1190
November11th to 20thNight
70%
760
31%
2470
29%
760
74%
760
44%
1243
November21st to endNight
63%
760
28%
2470
29%
760
65%
760
36%
1359
December1st to 10thNight
61%
760
22%
2470
22%
760
63%
760
31%
1445
December11th to 20thNight
59%
759
20%
2921
19%
758
61%
758
21%
1802
December21st to endNight
47%
823
10%
4421
14%
817
50%
817
12%
2826

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
45%25%5%35%5%6%7%53%
79011
Night
5%6%35%5%345%6%8%50%
80627
TransparencyDay
27%7%11%19%20%16%
78738
Night
29%7%12%20%19%13%
80422
SeeingDay
7%6%16%27%26%19%
13938
Night
8%418%41%26%3
24211

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
412%7%10%7%5%7%6%7%8%26%
2858
11th to 20thDay
5%10%5%10%9%47%7%7%8%27%
2860
21st to endDay
7%10%49%8%5%6%5%6%7%34%
3146
February1st to 10thDay
5%9%47%6%45%6%6%11%37%
1710
11th to 20thDay
6%7%47%6%36%6%6%7%43%
1821
21st to endDay
5%9%35%6%3446%8%47%
1570
March1st to 10thDay
6%7%36%5%35%5%6%8%47%
1968
11th to 20thDay
5%7%25%6%35%5%7%8%48%
1980
21st to endDay
6%7%26%6%35%7%6%8%44%
2178
April1st to 10thDay
5%5%25%5%345%6%8%54%
1980
11th to 20thDay
5%6%26%5%25%447%54%
2261
21st to endDay
6%5%25%42345%6%57%
2340
May1st to 10thDay
44245%36%5%6%8%53%
2340
11th to 20thDay
5%4234335%6%10%55%
2301
21st to endDay
45%235%35%5%6%8%55%
2530
June1st to 10thDay
221232446%8%65%
2340
11th to 20thDay
3312322446%71%
2340
21st to endDay
22221335%6%75%
2340
July1st to 10thDay
321233446%8%67%
2340
11th to 20thDay
3314335%5%6%8%58%
2340
21st to endDay
32245%45%6%7%11%53%
2545
August1st to 10thDay
2223445%45%8%62%
2328
11th to 20thDay
221343345%7%65%
2299
21st to endDay
321332345%6%66%
2530
September1st to 10thDay
3212223345%74%
1985
11th to 20thDay
2313322446%72%
1980
21st to endDay
221321233475%
1980
October1st to 10thDay
6%424324447%61%
1944
11th to 20thDay
3414323446%68%
1800
21st to endDay
5%42432345%6%63%
1958
November1st to 10thDay
5%5%15%5%35%45%9%53%
1674
11th to 20thDay
6%425%4345%7%8%53%
1710
21st to endDay
6%7%36%5%36%5%5%7%47%
1710
December1st to 10thDay
6%8%46%7%46%6%6%7%39%
1710
11th to 20thDay
5%9%49%8%6%6%6%7%8%31%
2169
21st to endDay
7%7%49%8%5%8%7%7%8%30%
3146
January1st to 10thNight
412%5%9%7%45%6%7%10%31%
4097
11th to 20thNight
6%11%48%8%45%46%9%33%
4110
21st to endNight
7%9%48%6%46%5%7%11%33%
4521
February1st to 10thNight
5%9%37%6%445%6%8%43%
2470
11th to 20thNight
6%8%46%5%345%5%7%46%
2244
21st to endNight
5%8%35%6%346%6%8%45%
1884
March1st to 10thNight
7%10%37%5%35%45%9%43%
2150
11th to 20thNight
5%7%34435%5%6%8%51%
1980
21st to endNight
6%7%36%5%35%5%6%7%46%
2178
April1st to 10thNight
7%7%25%5%345%47%49%
1980
11th to 20thNight
6%6%36%6%2445%7%51%
1643
21st to endNight
8%5%25%4335%5%7%54%
1620
May1st to 10thNight
7%6%25%6%36%45%8%47%
1620
11th to 20thNight
5%4345%2445%7%56%
1594
21st to endNight
5%5%25%5%25%46%8%52%
1746
June1st to 10thNight
332343445%8%61%
1620
11th to 20thNight
331432235%470%
1620
21st to endNight
221332345%6%69%
1620
July1st to 10thNight
22245%35%5%47%63%
1620
11th to 20thNight
35%26%6%37%5%6%8%49%
1620
21st to endNight
3325%6%36%7%7%12%47%
1773
August1st to 10thNight
34145%345%6%8%55%
1611
11th to 20thNight
13145%346%6%7%59%
1602
21st to endNight
34134335%5%7%62%
1822
September1st to 10thNight
321222335%7%71%
1975
11th to 20thNight
2214423346%69%
1980
21st to endNight
4213223235%72%
1980
October1st to 10thNight
5%324423446%62%
2016
11th to 20thNight
4323423446%66%
2160
21st to endNight
431332335%8%64%
2394
November1st to 10thNight
45%2432435%7%61%
2405
11th to 20thNight
5%425%32446%8%58%
2470
21st to endNight
7%7%35%42346%10%48%
2470
December1st to 10thNight
7%9%36%5%345%5%8%47%
2470
11th to 20thNight
7%8%46%6%46%7%7%11%35%
3041
21st to endNight
6%10%5%9%9%5%6%7%7%10%28%
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
46%12%20%16%6%
2859
11th to 20thDay
47%12%20%17%4
2860
21st to endDay
42%15%19%17%7%1
3146
February1st to 10thDay
38%10%18%21%11%2
1710
11th to 20thDay
37%7%15%24%14%2
1831
21st to endDay
32%7%12%29%18%2
1570
March1st to 10thDay
32%8%11%27%19%2
1968
11th to 20thDay
32%5%11%29%17%6%
1980
21st to endDay
34%8%13%25%15%4
2178
April1st to 10thDay
28%6%10%26%20%10%
1980
11th to 20thDay
29%410%22%24%11%
2264
21st to endDay
27%5%9%22%28%9%
2340
May1st to 10thDay
24%7%10%19%28%12%
2340
11th to 20thDay
23%6%8%20%29%14%
2304
21st to endDay
23%6%10%20%28%14%
2530
June1st to 10thDay
15%5%7%14%30%29%
2340
11th to 20thDay
14%46%11%26%39%
2340
21st to endDay
10%248%24%52%
2340
July1st to 10thDay
16%36%10%16%49%
2276
11th to 20thDay
21%6%7%14%20%32%
2271
21st to endDay
22%6%12%17%19%24%
2404
August1st to 10thDay
19%48%13%22%33%
2313
11th to 20thDay
17%5%6%10%20%42%
2299
21st to endDay
16%5%6%13%28%32%
2530
September1st to 10thDay
13%36%11%27%41%
1985
11th to 20thDay
14%47%16%25%34%
1980
21st to endDay
14%35%15%34%29%
1980
October1st to 10thDay
22%5%7%19%32%15%
1944
11th to 20thDay
17%47%22%38%11%
1800
21st to endDay
20%410%31%28%7%
1958
November1st to 10thDay
26%6%14%26%23%5%
1674
11th to 20thDay
26%6%12%33%20%3
1710
21st to endDay
33%6%15%26%19%2
1710
December1st to 10thDay
39%7%16%25%10%3
1710
11th to 20thDay
43%11%17%21%8%
2168
21st to endDay
40%13%18%16%11%1
3146
January1st to 10thNight
40%12%18%22%7%
4097
11th to 20thNight
41%13%21%18%6%
4110
21st to endNight
37%13%22%19%8%1
4521
February1st to 10thNight
37%7%16%26%12%2
2470
11th to 20thNight
35%6%14%21%21%3
2245
21st to endNight
35%7%10%25%20%3
1884
March1st to 10thNight
35%7%10%26%20%2
2150
11th to 20thNight
28%6%10%28%23%6%
1980
21st to endNight
34%5%13%25%17%5%
2178
April1st to 10thNight
33%6%9%23%18%12%
1980
11th to 20thNight
32%5%8%22%22%11%
1643
21st to endNight
27%5%11%21%28%7%
1620
May1st to 10thNight
33%7%8%16%25%12%
1620
11th to 20thNight
23%6%9%17%28%16%
1595
21st to endNight
27%7%8%21%25%12%
1746
June1st to 10thNight
18%6%8%13%29%27%
1620
11th to 20thNight
15%5%7%9%24%41%
1620
21st to endNight
13%35%7%19%52%
1620
July1st to 10thNight
18%5%7%9%12%49%
1575
11th to 20thNight
27%7%8%11%16%31%
1566
21st to endNight
26%8%12%16%17%21%
1674
August1st to 10thNight
22%6%9%16%16%30%
1602
11th to 20thNight
19%5%8%16%13%40%
1602
21st to endNight
19%5%6%13%23%34%
1822
September1st to 10thNight
13%47%12%22%42%
1975
11th to 20thNight
16%47%16%21%37%
1980
21st to endNight
16%35%13%29%34%
1980
October1st to 10thNight
22%5%7%15%34%18%
2016
11th to 20thNight
19%46%16%42%14%
2160
21st to endNight
19%48%26%36%8%
2394
November1st to 10thNight
23%49%25%30%9%
2405
11th to 20thNight
23%5%11%32%24%5%
2470
21st to endNight
31%410%30%23%2
2470
December1st to 10thNight
34%6%13%29%14%3
2470
11th to 20thNight
37%10%16%27%10%
3041
21st to endNight
43%11%14%17%14%1
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
17%5%13%33%23%9%
270
11th to 20thDay
12%5%17%32%24%9%
270
21st to endDay
13%312%29%26%16%
297
February1st to 10thDay
7%8%19%34%18%13%
270
11th to 20thDay
9%7%20%30%26%9%
426
21st to endDay
7%9%23%32%22%7%
382
March1st to 10thDay
12%10%21%27%23%7%
449
11th to 20thDay
7%8%20%30%23%12%
420
21st to endDay
14%11%27%25%17%6%
462
April1st to 10thDay
9%9%20%24%25%12%
420
11th to 20thDay
9%14%23%28%18%8%
412
21st to endDay
10%11%21%23%18%16%
420
May1st to 10thDay
48%22%32%21%13%
423
11th to 20thDay
7%7%17%24%27%18%
448
21st to endDay
7%5%15%25%24%23%
485
June1st to 10thDay
46%15%27%26%22%
450
11th to 20thDay
48%18%22%27%21%
450
21st to endDay
3414%28%31%20%
450
July1st to 10thDay
3113%32%29%21%
446
11th to 20thDay
429%29%28%28%
444
21st to endDay
325%20%37%32%
487
August1st to 10thDay
3111%30%32%23%
447
11th to 20thDay
3112%24%30%31%
437
21st to endDay
3312%21%32%28%
495
September1st to 10thDay
4312%22%26%33%
450
11th to 20thDay
35%18%20%28%25%
450
21st to endDay
4415%20%29%28%
450
October1st to 10thDay
5%5%17%22%28%23%
414
11th to 20thDay
5%311%24%27%31%
270
21st to endDay
9%310%28%31%19%
297
November1st to 10thDay
9%7%13%26%23%22%
270
11th to 20thDay
5%5%12%29%31%17%
270
21st to endDay
9%311%23%33%20%
270
December1st to 10thDay
11%311%35%26%14%
270
11th to 20thDay
10%5%8%32%36%10%
270
21st to endDay
12%7%15%37%23%7%
297
January1st to 10thNight
10%5%13%42%25%6%
760
11th to 20thNight
10%415%41%25%5%
760
21st to endNight
11%314%43%24%5%
836
February1st to 10thNight
11%319%45%19%3
760
11th to 20thNight
11%320%44%20%2
744
21st to endNight
8%7%23%46%15%1
628
March1st to 10thNight
13%5%22%41%18%1
750
11th to 20thNight
8%421%42%23%1
720
21st to endNight
10%6%27%39%16%1
792
April1st to 10thNight
10%6%25%40%18%2
720
11th to 20thNight
8%8%30%39%14%1
575
21st to endNight
11%7%24%38%18%2
540
May1st to 10thNight
13%5%22%40%18%2
540
11th to 20thNight
8%6%18%42%24%2
531
21st to endNight
8%6%21%36%27%1
584
June1st to 10thNight
5%5%22%43%24%1
540
11th to 20thNight
6%6%26%40%23%
540
21st to endNight
4221%46%26%1
540
July1st to 10thNight
4115%42%36%2
525
11th to 20thNight
5%211%44%35%3
522
21st to endNight
5%19%42%41%1
591
August1st to 10thNight
5%117%46%30%1
537
11th to 20thNight
3213%45%35%2
534
21st to endNight
5%212%38%39%3
634
September1st to 10thNight
4212%35%41%7%
720
11th to 20thNight
4117%34%36%7%
720
21st to endNight
5%215%33%38%7%
720
October1st to 10thNight
6%318%40%28%5%
720
11th to 20thNight
4313%40%34%6%
720
21st to endNight
6%318%36%32%5%
792
November1st to 10thNight
7%317%37%31%4
740
11th to 20thNight
6%316%44%26%5%
760
21st to endNight
10%216%38%28%6%
760
December1st to 10thNight
10%415%47%21%3
760
11th to 20thNight
11%314%44%27%1
760
21st to endNight
13%7%16%44%19%2
836
Page generated at 2024-03-05 05:24:02. Version ac07

Copyright © 2024 Attilla Danko.


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