SAAA Twin Buttes Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the SAAA Twin Buttes Site clear sky chart from 2005-11-06 to 2024-11-02.

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
48%
24677
30%
94328
19%
24488
60%
24488
37%
44804

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
38%
940
37%
3956
13%
926
51%
926
36%
1755
January11th to 20thNight
39%
883
39%
3785
13%
869
53%
869
37%
1481
January21st to endNight
36%
825
25%
4077
17%
814
55%
814
26%
1939
February1st to 10thNight
32%
760
34%
2280
13%
760
50%
760
39%
1235
February11th to 20thNight
28%
743
26%
2218
10%
740
42%
740
33%
1240
February21st to endNight
24%
628
31%
1884
8%
628
43%
628
36%
998
March1st to 10thNight
28%
757
36%
3677
10%
744
44%
744
27%
1572
March11th to 20thNight
30%
571
28%
3436
14%
555
48%
555
18%
1780
March21st to endNight
25%
622
20%
3651
13%
605
49%
605
24%
1594
April1st to 10thNight
26%
570
34%
1957
12%
570
53%
570
39%
950
April11th to 20thNight
25%
563
30%
1877
10%
563
49%
563
35%
992
April21st to endNight
27%
570
32%
1900
12%
570
54%
570
43%
905
May1st to 10thNight
32%
568
32%
2815
15%
559
53%
559
25%
1427
May11th to 20thNight
39%
556
21%
2718
17%
541
52%
541
29%
1230
May21st to endNight
44%
608
18%
3064
16%
593
60%
593
30%
1324
June1st to 10thNight
61%
570
25%
1710
20%
570
71%
570
53%
821
June11th to 20thNight
58%
570
28%
1710
24%
570
68%
570
58%
791
June21st to endNight
68%
570
27%
1710
27%
570
72%
570
51%
835
July1st to 10thNight
76%
536
31%
2506
21%
535
79%
535
36%
1042
July11th to 20thNight
81%
536
32%
2298
36%
533
86%
533
58%
782
July21st to endNight
84%
607
30%
2746
40%
569
88%
569
42%
1128
August1st to 10thNight
85%
547
38%
2751
38%
544
88%
544
46%
984
August11th to 20thNight
75%
544
25%
2564
34%
543
79%
543
37%
1005
August21st to endNight
82%
608
18%
3152
25%
605
85%
605
28%
1469
September1st to 10thNight
74%
570
26%
2019
30%
570
77%
570
36%
1066
September11th to 20thNight
70%
570
25%
2090
26%
570
73%
570
34%
1092
September21st to endNight
68%
570
33%
2090
29%
570
75%
570
41%
1006
October1st to 10thNight
66%
570
39%
2090
36%
570
74%
570
49%
917
October11th to 20thNight
54%
570
37%
2090
25%
570
69%
570
41%
979
October21st to endNight
53%
802
37%
2474
21%
802
64%
802
45%
1241
November1st to 10thNight
52%
935
32%
2431
15%
935
60%
935
49%
1332
November11th to 20thNight
50%
950
30%
2470
14%
950
58%
950
49%
1335
November21st to endNight
39%
950
32%
2470
13%
950
49%
950
39%
1478
December1st to 10thNight
42%
950
35%
2470
14%
950
55%
950
44%
1395
December11th to 20thNight
38%
950
33%
2885
13%
949
51%
949
35%
1640
December21st to endNight
38%
1038
22%
4307
13%
1026
51%
1026
32%
2044

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%424333346%60%
100886
Night
7%41433335%7%61%
98210
TransparencyDay
26%49%22%25%14%
100700
Night
23%410%22%25%16%
98068
SeeingDay
9%7%24%32%22%6%
14929
Night
9%7%32%38%14%1
24851

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
9%6%24322235%62%
2847
11th to 20thDay
6%5%13222246%67%
2978
21st to endDay
10%6%23333346%56%
3487
February1st to 10thDay
9%5%25%344235%58%
1900
11th to 20thDay
10%5%25%343346%55%
1849
21st to endDay
10%6%23322336%60%
1570
March1st to 10thDay
9%5%25%335%346%55%
3130
11th to 20thDay
20%6%24333345%47%
3475
21st to endDay
5%6%25%34435%7%57%
3814
April1st to 10thDay
8%314334347%60%
2217
11th to 20thDay
10%5%25%333246%56%
2254
21st to endDay
9%414322245%63%
2280
May1st to 10thDay
12%5%25%443345%54%
4072
11th to 20thDay
13%5%25%332236%55%
4082
21st to endDay
8%42433435%7%56%
4477
June1st to 10thDay
421333435%9%63%
2470
11th to 20thDay
431333445%7%64%
2470
21st to endDay
5%41333448%7%57%
2470
July1st to 10thDay
4214445%5%6%8%57%
4120
11th to 20thDay
21233336%9%67%
4120
21st to endDay
431333435%8%63%
4386
August1st to 10thDay
111122335%6%75%
3785
11th to 20thDay
4213223248%68%
3726
21st to endDay
3325%5%5%446%9%54%
4180
September1st to 10thDay
9%3245%45%45%7%52%
2161
11th to 20thDay
9%425%44435%8%51%
2090
21st to endDay
10%21435%4346%58%
2090
October1st to 10thDay
5%324323346%66%
2090
11th to 20thDay
9%323323235%66%
2090
21st to endDay
10%41432213466%
2098
November1st to 10thDay
10%424222246%63%
1682
11th to 20thDay
6%314234246%64%
1710
21st to endDay
10%435%433346%57%
1710
December1st to 10thDay
12%5%24433246%57%
1710
11th to 20thDay
8%5%25%334346%57%
2161
21st to endDay
11%6%1321222466%
3135
January1st to 10thNight
7%5%24233245%63%
4108
11th to 20thNight
7%413222235%70%
4020
21st to endNight
12%5%14333346%57%
4180
February1st to 10thNight
9%6%24323346%59%
2280
11th to 20thNight
12%5%25%333336%56%
2218
21st to endNight
10%5%1333325%6%59%
1884
March1st to 10thNight
7%5%2433435%5%59%
3734
11th to 20thNight
17%5%1433335%6%50%
3485
21st to endNight
5%425%44435%7%57%
3817
April1st to 10thNight
6%41443335%7%61%
1957
11th to 20thNight
9%42334335%5%58%
1877
21st to endNight
8%312332235%67%
1900
May1st to 10thNight
12%415%33335%5%55%
2831
11th to 20thNight
8%42323335%7%61%
2823
21st to endNight
6%315%23336%9%58%
3090
June1st to 10thNight
221323437%11%63%
1710
11th to 20thNight
321223346%9%66%
1710
21st to endNight
331323435%7%66%
1710
July1st to 10thNight
421334336%9%62%
2850
11th to 20thNight
212222248%75%
2850
21st to endNight
321443325%8%65%
3159
August1st to 10thNight
1213233347%72%
3155
11th to 20thNight
321323336%9%65%
3113
21st to endNight
3314445%5%7%11%54%
3487
September1st to 10thNight
7%42434446%7%55%
2019
11th to 20thNight
9%32444346%7%54%
2090
21st to endNight
9%414333247%60%
2090
October1st to 10thNight
5%213223347%67%
2090
11th to 20thNight
10%41322323466%
2090
21st to endNight
9%41322334466%
2474
November1st to 10thNight
10%413233235%65%
2431
11th to 20thNight
6%31333435%5%64%
2470
21st to endNight
12%414333346%56%
2470
December1st to 10thNight
10%414233246%60%
2470
11th to 20thNight
8%6%25%433347%55%
3036
21st to endNight
9%5%24323246%61%
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
26%35%15%28%23%
2848
11th to 20thDay
21%28%16%34%19%
2978
21st to endDay
29%47%18%31%11%
3487
February1st to 10thDay
30%35%16%25%22%
1900
11th to 20thDay
31%36%20%22%18%
1859
21st to endDay
28%35%11%31%22%
1570
March1st to 10thDay
32%36%10%23%26%
3130
11th to 20thDay
40%6%7%12%21%15%
3475
21st to endDay
26%49%16%24%21%
3814
April1st to 10thDay
24%48%19%23%22%
2217
11th to 20thDay
30%5%6%15%24%20%
2254
21st to endDay
26%37%19%27%18%
2280
May1st to 10thDay
33%5%8%12%17%25%
4110
11th to 20thDay
32%48%17%24%14%
4086
21st to endDay
26%7%11%21%17%17%
4489
June1st to 10thDay
18%6%13%30%25%7%
2470
11th to 20thDay
18%6%12%26%26%11%
2470
21st to endDay
23%6%12%25%24%9%
2470
July1st to 10thDay
25%5%14%36%17%2
4056
11th to 20thDay
15%415%36%24%5%
4051
21st to endDay
20%5%11%32%29%4
4248
August1st to 10thDay
12%310%34%35%6%
3772
11th to 20thDay
16%413%38%25%3
3762
21st to endDay
27%6%17%22%24%5%
4179
September1st to 10thDay
31%7%10%21%20%10%
2161
11th to 20thDay
32%6%12%20%23%7%
2090
21st to endDay
26%410%20%24%15%
2090
October1st to 10thDay
20%6%10%23%26%15%
2090
11th to 20thDay
23%37%17%26%22%
2090
21st to endDay
25%2416%33%19%
2098
November1st to 10thDay
24%47%25%24%16%
1682
11th to 20thDay
22%49%20%26%18%
1710
21st to endDay
30%36%17%27%16%
1710
December1st to 10thDay
31%36%20%27%13%
1710
11th to 20thDay
30%39%16%24%18%
2159
21st to endDay
25%2318%31%21%
3135
January1st to 10thNight
23%36%15%32%21%
4108
11th to 20thNight
20%26%21%28%23%
4020
21st to endNight
29%47%18%28%15%
4180
February1st to 10thNight
28%38%14%25%22%
2280
11th to 20thNight
32%26%16%23%22%
2218
21st to endNight
26%46%13%27%24%
1884
March1st to 10thNight
26%37%14%29%22%
3734
11th to 20thNight
35%5%10%15%19%16%
3485
21st to endNight
25%5%11%18%22%18%
3817
April1st to 10thNight
23%49%22%18%24%
1957
11th to 20thNight
26%6%8%19%20%21%
1877
21st to endNight
21%410%22%28%15%
1900
May1st to 10thNight
29%7%9%16%21%19%
2858
11th to 20thNight
24%6%10%22%21%16%
2824
21st to endNight
22%7%13%23%18%17%
3099
June1st to 10thNight
15%7%17%32%24%5%
1710
11th to 20thNight
15%414%30%27%10%
1710
21st to endNight
16%8%13%27%27%9%
1710
July1st to 10thNight
19%5%16%38%19%3
2805
11th to 20thNight
10%212%40%30%7%
2796
21st to endNight
17%411%35%30%3
3059
August1st to 10thNight
14%310%27%40%6%
3144
11th to 20thNight
16%415%38%24%3
3143
21st to endNight
23%7%20%24%22%4
3487
September1st to 10thNight
26%8%12%23%21%11%
2019
11th to 20thNight
28%6%14%21%23%8%
2090
21st to endNight
24%49%24%21%17%
2090
October1st to 10thNight
18%412%23%24%19%
2090
11th to 20thNight
24%38%16%26%23%
2090
21st to endNight
23%35%17%30%22%
2474
November1st to 10thNight
23%38%21%25%19%
2431
11th to 20thNight
21%47%21%26%21%
2470
21st to endNight
31%36%16%27%18%
2470
December1st to 10thNight
26%37%22%26%16%
2470
11th to 20thNight
30%36%18%24%19%
3037
21st to endNight
26%35%17%29%20%
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
12%18%32%30%7%1
270
11th to 20thDay
13%17%30%27%11%2
270
21st to endDay
10%13%42%23%10%1
297
February1st to 10thDay
17%12%40%22%9%
270
11th to 20thDay
17%12%43%23%41
270
21st to endDay
17%16%44%20%3
225
March1st to 10thDay
15%11%43%26%6%
270
11th to 20thDay
21%11%36%19%11%2
270
21st to endDay
12%18%41%21%6%1
297
April1st to 10thDay
11%15%44%23%6%1
397
11th to 20thDay
12%17%44%22%4
452
21st to endDay
12%17%39%25%7%1
460
May1st to 10thDay
9%12%39%32%7%1
643
11th to 20thDay
13%9%31%32%12%3
675
21st to endDay
10%6%33%37%13%1
734
June1st to 10thDay
4319%48%24%3
680
11th to 20thDay
3125%45%21%4
680
21st to endDay
3213%39%35%8%
680
July1st to 10thDay
6%37%35%39%11%
671
11th to 20thDay
115%38%44%10%
668
21st to endDay
21434%45%14%
696
August1st to 10thDay
21432%44%17%
487
11th to 20thDay
8%1432%41%14%
477
21st to endDay
425%28%44%17%
539
September1st to 10thDay
9%25%31%36%17%
371
11th to 20thDay
5%35%25%42%20%
300
21st to endDay
13%38%26%33%17%
300
October1st to 10thDay
4314%36%33%11%
300
11th to 20thDay
11%425%38%20%3
300
21st to endDay
16%7%27%26%18%5%
330
November1st to 10thDay
16%5%30%30%17%1
273
11th to 20thDay
12%11%28%30%13%6%
270
21st to endDay
16%16%32%21%12%3
270
December1st to 10thDay
16%8%26%37%10%3
270
11th to 20thDay
10%13%35%31%10%1
270
21st to endDay
15%13%38%24%10%
297
January1st to 10thNight
10%8%39%34%8%
950
11th to 20thNight
11%9%35%37%8%
889
21st to endNight
10%10%39%34%6%
836
February1st to 10thNight
13%10%42%30%6%
760
11th to 20thNight
13%13%43%28%3
744
21st to endNight
14%14%46%25%2
628
March1st to 10thNight
12%12%44%28%4
760
11th to 20thNight
13%11%43%29%4
575
21st to endNight
6%13%52%25%3
627
April1st to 10thNight
6%13%51%26%4
570
11th to 20thNight
9%10%53%25%3
563
21st to endNight
8%10%53%25%5%
570
May1st to 10thNight
6%10%48%31%4
570
11th to 20thNight
9%8%40%33%9%
561
21st to endNight
5%441%39%10%1
617
June1st to 10thNight
3230%52%13%1
570
11th to 20thNight
2136%52%9%
570
21st to endNight
3221%52%21%1
570
July1st to 10thNight
6%110%52%30%2
555
11th to 20thNight
219%60%26%1
552
21st to endNight
216%62%28%1
624
August1st to 10thNight
118%55%34%1
567
11th to 20thNight
5%17%48%36%4
564
21st to endNight
328%43%41%3
627
September1st to 10thNight
7%28%44%36%2
570
11th to 20thNight
10%17%46%33%2
570
21st to endNight
11%115%45%26%1
570
October1st to 10thNight
5%222%46%24%
570
11th to 20thNight
11%5%26%43%14%
570
21st to endNight
10%6%28%41%14%1
802
November1st to 10thNight
11%5%28%40%15%1
935
11th to 20thNight
6%9%32%40%12%1
950
21st to endNight
14%9%35%31%11%1
950
December1st to 10thNight
12%7%36%36%9%
950
11th to 20thNight
13%10%35%34%8%
950
21st to endNight
11%9%37%37%6%
1045
Page generated at 2024-10-30 12:19:24. Version ac07

Copyright © 2024 Attilla Danko.


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