Bald Butte Observing Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bald Butte Observing 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
49%
23705
16%
94137
15%
23575
52%
23575
19%
58655

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
28%
749
9%
4386
6%
736
31%
736
5%
3410
January11th to 20thNight
37%
748
13%
4364
9%
740
39%
740
8%
3064
January21st to endNight
36%
826
6%
4836
9%
814
39%
814
7%
3627
February1st to 10thNight
30%
760
9%
2641
7%
760
35%
760
11%
1997
February11th to 20thNight
39%
743
12%
2253
11%
740
42%
740
17%
1632
February21st to endNight
35%
628
12%
1884
10%
628
40%
628
14%
1426
March1st to 10thNight
42%
752
24%
3695
12%
744
44%
744
12%
2280
March11th to 20thNight
45%
745
17%
3662
14%
740
48%
740
17%
1872
March21st to endNight
39%
818
9%
3500
7%
814
42%
814
12%
2549
April1st to 10thNight
46%
760
14%
1900
7%
760
47%
760
23%
1371
April11th to 20thNight
41%
693
18%
1821
9%
693
45%
693
26%
1248
April21st to endNight
48%
570
16%
1710
11%
570
52%
570
24%
1149
May1st to 10thNight
54%
481
22%
2581
19%
478
61%
478
19%
1407
May11th to 20thNight
60%
370
17%
2446
25%
364
62%
364
17%
1119
May21st to endNight
57%
404
8%
2747
15%
399
61%
399
13%
1552
June1st to 10thNight
59%
380
12%
1439
15%
380
62%
380
23%
843
June11th to 20thNight
48%
380
14%
1330
13%
380
53%
380
26%
788
June21st to endNight
67%
380
18%
1441
25%
380
70%
380
35%
713
July1st to 10thNight
79%
363
24%
2068
32%
360
84%
360
51%
565
July11th to 20thNight
76%
362
26%
1862
39%
359
83%
359
52%
564
July21st to endNight
78%
408
26%
2123
46%
383
85%
383
43%
726
August1st to 10thNight
79%
372
33%
2082
41%
367
84%
367
34%
822
August11th to 20thNight
78%
519
27%
2336
30%
509
82%
509
39%
1026
August21st to endNight
70%
779
28%
2985
21%
771
74%
771
41%
1429
September1st to 10thNight
76%
760
35%
1900
21%
760
78%
760
59%
994
September11th to 20thNight
69%
760
29%
2022
22%
760
71%
760
42%
1190
September21st to endNight
63%
760
27%
2090
22%
760
66%
760
41%
1214
October1st to 10thNight
60%
760
25%
2135
21%
760
64%
760
37%
1263
October11th to 20thNight
56%
760
20%
2389
20%
760
59%
760
26%
1476
October21st to endNight
48%
836
20%
2717
18%
836
53%
836
24%
1753
November1st to 10thNight
41%
748
14%
2430
14%
748
44%
748
17%
1731
November11th to 20thNight
38%
760
11%
2503
10%
760
42%
760
16%
1802
November21st to endNight
44%
790
12%
2690
10%
790
48%
790
17%
1849
December1st to 10thNight
42%
950
10%
2850
8%
950
45%
950
16%
2145
December11th to 20thNight
30%
948
6%
3425
4%
948
31%
948
8%
2793
December21st to endNight
25%
883
5%
4894
4%
874
29%
874
6%
3266

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
10%8%37%44445%6%44%
101282
Night
12%9%37%5%4445%6%40%
97811
TransparencyDay
41%311%23%15%7%
101026
Night
45%311%21%13%6%
97656
SeeingDay
15%6%19%27%23%10%
14592
Night
18%5%16%36%22%4
23860

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
14%18%7%12%7%5%6%46%6%16%
2539
11th to 20thDay
17%15%5%11%5%5%446%6%20%
2540
21st to endDay
21%16%5%12%7%5%4346%16%
2794
February1st to 10thDay
17%18%49%6%5%445%6%21%
1535
11th to 20thDay
16%16%49%7%5%4446%23%
1816
21st to endDay
13%20%49%6%5%5%447%23%
1570
March1st to 10thDay
11%13%410%6%6%6%5%6%7%27%
3138
11th to 20thDay
9%8%37%5%5%5%45%6%45%
3291
21st to endDay
13%16%5%11%7%7%6%5%6%6%19%
4099
April1st to 10thDay
13%11%310%6%6%6%5%6%8%26%
2280
11th to 20thDay
11%11%38%5%5%5%5%6%7%34%
2306
21st to endDay
12%9%37%7%6%6%47%7%32%
2470
May1st to 10thDay
10%8%26%44446%8%44%
4250
11th to 20thDay
7%5%25%34445%8%53%
4377
21st to endDay
9%8%38%6%5%6%5%7%9%34%
4813
June1st to 10thDay
14%9%37%5%5%5%46%7%36%
2731
11th to 20thDay
12%7%26%5%5%446%7%40%
2850
21st to endDay
6%5%2434445%6%59%
2730
July1st to 10thDay
221212223480%
4420
11th to 20thDay
221312223479%
4420
21st to endDay
1112223346%75%
4790
August1st to 10thDay
3314233347%69%
4400
11th to 20thDay
3313333347%67%
4086
21st to endDay
331433335%6%66%
4244
September1st to 10thDay
4314223247%68%
2280
11th to 20thDay
7%5%35%44446%7%50%
2157
21st to endDay
8%426%44445%8%51%
2090
October1st to 10thDay
13%8%37%433346%46%
2043
11th to 20thDay
11%6%27%5%45%46%8%41%
1791
21st to endDay
16%10%39%45%436%6%34%
1881
November1st to 10thDay
22%10%38%6%5%445%7%26%
1683
11th to 20thDay
20%11%411%7%5%6%45%5%22%
1675
21st to endDay
17%13%49%6%6%6%5%6%6%22%
1466
December1st to 10thDay
18%14%412%7%45%5%6%6%19%
1330
11th to 20thDay
18%18%5%11%7%6%5%5%4418%
1685
21st to endDay
16%15%410%6%4446%7%24%
2712
January1st to 10thNight
21%15%5%11%6%6%5%35%6%17%
4406
11th to 20thNight
17%15%5%9%5%5%446%6%24%
4420
21st to endNight
21%13%5%10%6%6%5%35%6%20%
4862
February1st to 10thNight
18%17%49%6%45%36%5%24%
2641
11th to 20thNight
15%13%5%9%5%4445%6%31%
2252
21st to endNight
14%15%410%6%6%5%45%5%25%
1884
March1st to 10thNight
10%12%49%5%6%5%45%7%34%
3736
11th to 20thNight
10%8%26%5%43345%49%
3688
21st to endNight
12%11%410%7%7%7%5%7%7%23%
3550
April1st to 10thNight
14%11%37%6%5%6%5%6%8%31%
1900
11th to 20thNight
14%10%37%6%4435%6%39%
1821
21st to endNight
12%9%38%5%5%5%45%7%37%
1710
May1st to 10thNight
11%5%26%45%5%5%6%8%43%
2713
11th to 20thNight
8%5%26%45%446%8%49%
2516
21st to endNight
14%7%37%5%45%5%6%8%37%
2762
June1st to 10thNight
10%5%37%5%6%5%5%6%7%42%
1439
11th to 20thNight
10%7%26%5%445%7%6%43%
1330
21st to endNight
6%416%35%435%5%57%
1441
July1st to 10thNight
21122223482%
2540
11th to 20thNight
1112112245%81%
2540
21st to endNight
2213222335%75%
2761
August1st to 10thNight
331322335%6%66%
2529
11th to 20thNight
231434445%5%66%
2751
21st to endNight
3324333346%65%
3429
September1st to 10thNight
5%31323235%7%66%
1900
11th to 20thNight
7%415%445%45%6%54%
2022
21st to endNight
9%5%26%34435%7%53%
2090
October1st to 10thNight
10%5%36%43346%6%50%
2135
11th to 20thNight
13%7%36%5%45%35%5%46%
2389
21st to endNight
16%7%37%5%5%436%6%41%
2717
November1st to 10thNight
20%10%38%6%5%435%7%29%
2430
11th to 20thNight
21%11%38%6%4445%6%29%
2503
21st to endNight
17%11%48%5%4446%6%31%
2690
December1st to 10thNight
17%12%38%6%5%5%45%7%27%
2850
11th to 20thNight
20%16%5%10%6%5%6%45%6%17%
3506
21st to endNight
17%13%48%7%5%5%45%7%27%
4958

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
71%314%11%1
2539
11th to 20thDay
65%312%15%5%
2540
21st to endDay
71%314%10%21
2794
February1st to 10thDay
64%5%15%12%5%
1535
11th to 20thDay
63%312%15%5%
1826
21st to endDay
62%49%19%6%1
1570
March1st to 10thDay
56%27%24%10%
3138
11th to 20thDay
41%215%34%7%
3291
21st to endDay
66%214%11%5%1
4099
April1st to 10thDay
55%415%19%7%
2280
11th to 20thDay
49%412%20%13%2
2309
21st to endDay
51%311%24%10%1
2470
May1st to 10thDay
40%211%33%13%1
4250
11th to 20thDay
31%212%34%17%4
4380
21st to endDay
47%219%25%6%1
4814
June1st to 10thDay
48%411%25%11%1
2731
11th to 20thDay
43%313%25%14%2
2850
21st to endDay
26%310%32%25%4
2730
July1st to 10thDay
11%2417%29%36%
4351
11th to 20thDay
11%2411%27%45%
4345
21st to endDay
11%3420%35%27%
4639
August1st to 10thDay
17%25%17%41%18%
4384
11th to 20thDay
19%26%39%26%8%
4126
21st to endDay
19%39%33%28%7%
4243
September1st to 10thDay
18%39%30%28%12%
2280
11th to 20thDay
32%312%26%21%6%
2157
21st to endDay
32%315%31%15%3
2090
October1st to 10thDay
41%311%28%15%1
2043
11th to 20thDay
40%315%28%13%1
1791
21st to endDay
51%314%23%7%1
1881
November1st to 10thDay
59%413%19%41
1683
11th to 20thDay
63%5%13%14%31
1675
21st to endDay
60%5%14%15%5%1
1466
December1st to 10thDay
65%5%11%15%31
1330
11th to 20thDay
71%314%10%2
1684
21st to endDay
60%217%16%4
2712
January1st to 10thNight
70%212%14%11
4406
11th to 20thNight
61%214%17%5%1
4420
21st to endNight
66%316%13%2
4862
February1st to 10thNight
62%414%14%5%1
2641
11th to 20thNight
56%316%18%7%
2253
21st to endNight
60%312%17%6%1
1884
March1st to 10thNight
51%27%28%11%1
3736
11th to 20thNight
40%211%38%10%
3688
21st to endNight
60%314%19%4
3550
April1st to 10thNight
51%313%24%9%
1900
11th to 20thNight
47%310%23%14%3
1821
21st to endNight
47%412%21%15%2
1710
May1st to 10thNight
40%19%29%18%3
2713
11th to 20thNight
34%28%30%21%4
2516
21st to endNight
47%219%23%9%1
2762
June1st to 10thNight
40%5%10%29%15%1
1439
11th to 20thNight
40%39%27%17%4
1330
21st to endNight
29%38%27%27%7%
1441
July1st to 10thNight
10%1316%29%41%
2500
11th to 20thNight
8%3411%21%53%
2492
21st to endNight
13%2215%29%39%
2674
August1st to 10thNight
18%3311%41%23%
2521
11th to 20thNight
19%35%28%33%12%
2777
21st to endNight
21%36%26%30%13%
3429
September1st to 10thNight
19%26%27%30%17%
1900
11th to 20thNight
30%38%25%26%8%
2022
21st to endNight
32%212%30%17%7%
2090
October1st to 10thNight
34%211%33%18%1
2135
11th to 20thNight
41%311%25%18%1
2389
21st to endNight
45%411%25%14%1
2717
November1st to 10thNight
55%312%23%6%1
2430
11th to 20thNight
57%215%19%5%1
2503
21st to endNight
53%315%22%6%
2690
December1st to 10thNight
57%6%15%18%41
2850
11th to 20thNight
69%313%13%2
3507
21st to endNight
60%218%15%6%
4958

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
28%7%22%20%18%4
180
11th to 20thDay
28%323%27%12%7%
180
21st to endDay
29%426%28%13%1
198
February1st to 10thDay
28%9%29%25%8%2
195
11th to 20thDay
28%11%18%27%14%3
439
21st to endDay
23%10%23%29%12%3
382
March1st to 10thDay
20%9%27%28%13%4
460
11th to 20thDay
19%7%18%27%21%8%
460
21st to endDay
20%9%26%26%16%3
506
April1st to 10thDay
21%9%20%26%18%6%
460
11th to 20thDay
17%9%29%24%15%6%
452
21st to endDay
14%8%22%30%20%6%
460
May1st to 10thDay
14%5%20%28%27%6%
463
11th to 20thDay
18%5%17%25%18%16%
488
21st to endDay
14%316%23%28%16%
529
June1st to 10thDay
16%414%26%27%13%
561
11th to 20thDay
15%6%23%29%21%6%
680
21st to endDay
6%417%29%31%13%
560
July1st to 10thDay
3215%29%36%14%
486
11th to 20thDay
4319%30%30%14%
484
21st to endDay
2317%28%34%17%
531
August1st to 10thDay
6%216%28%29%19%
487
11th to 20thDay
4310%27%34%22%
477
21st to endDay
9%318%24%29%17%
539
September1st to 10thDay
6%218%26%31%17%
490
11th to 20thDay
10%5%16%27%27%16%
490
21st to endDay
11%6%17%31%27%8%
490
October1st to 10thDay
15%7%15%31%24%8%
490
11th to 20thDay
13%7%17%29%23%9%
381
21st to endDay
25%6%20%33%14%3
330
November1st to 10thDay
25%6%27%31%11%
273
11th to 20thDay
24%8%25%25%16%3
253
21st to endDay
23%323%33%15%3
180
December1st to 10thDay
31%5%21%24%14%6%
180
11th to 20thDay
32%7%24%24%8%3
180
21st to endDay
32%7%24%26%9%4
198
January1st to 10thNight
31%8%17%29%13%2
760
11th to 20thNight
26%7%16%33%15%4
760
21st to endNight
22%5%17%36%18%2
836
February1st to 10thNight
27%8%19%34%11%2
760
11th to 20thNight
23%6%18%34%16%2
744
21st to endNight
23%10%17%34%14%2
628
March1st to 10thNight
21%419%35%18%3
760
11th to 20thNight
17%6%19%32%23%2
760
21st to endNight
22%419%37%15%2
836
April1st to 10thNight
21%5%14%38%19%3
760
11th to 20thNight
18%6%22%35%16%3
693
21st to endNight
16%419%38%21%3
570
May1st to 10thNight
12%320%35%25%3
488
11th to 20thNight
13%411%33%30%10%
374
21st to endNight
14%412%32%31%6%
411
June1st to 10thNight
12%5%13%37%27%6%
380
11th to 20thNight
12%6%22%33%23%4
380
21st to endNight
8%214%39%32%5%
380
July1st to 10thNight
4111%38%39%6%
370
11th to 20thNight
2115%45%33%3
368
21st to endNight
2212%37%42%6%
416
August1st to 10thNight
5%28%38%40%7%
378
11th to 20thNight
3110%35%42%9%
528
21st to endNight
5%215%38%36%4
793
September1st to 10thNight
6%112%41%31%8%
760
11th to 20thNight
9%211%34%37%8%
760
21st to endNight
12%214%38%28%5%
760
October1st to 10thNight
13%213%44%25%3
760
11th to 20thNight
17%5%12%35%26%5%
760
21st to endNight
19%418%38%16%5%
836
November1st to 10thNight
25%5%15%38%16%1
748
11th to 20thNight
26%6%17%34%14%2
760
21st to endNight
22%6%15%33%20%4
790
December1st to 10thNight
24%415%38%16%2
950
11th to 20thNight
29%5%16%36%13%1
950
21st to endNight
33%8%19%29%10%1
893
Page generated at 2024-10-30 10:19:20. Version ac07

Copyright © 2024 Attilla Danko.


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