Boerne
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Boerne clear sky chart from 2005-11-06 to 2024-01-31.

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
44%
23800
25%
74552
16%
23743
53%
23743
31%
43633

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
36%
948
30%
2458
11%
946
48%
946
35%
1492
January11th to 20thNight
31%
950
26%
2470
9%
950
42%
950
30%
1556
January21st to endNight
31%
862
30%
2530
11%
862
45%
862
26%
1541
February1st to 10thNight
28%
720
27%
2160
9%
720
42%
720
26%
1306
February11th to 20thNight
26%
704
23%
2098
9%
700
38%
700
26%
1276
February21st to endNight
18%
592
26%
1776
5%
592
36%
592
23%
1100
March1st to 10thNight
24%
601
24%
2041
9%
601
39%
601
22%
1256
March11th to 20thNight
26%
540
22%
1980
11%
540
39%
540
22%
1198
March21st to endNight
23%
594
25%
2178
12%
594
41%
594
25%
1237
April1st to 10thNight
25%
540
25%
1980
11%
540
44%
540
24%
1133
April11th to 20thNight
23%
533
22%
1895
10%
533
40%
533
23%
1142
April21st to endNight
24%
540
27%
1710
13%
540
42%
540
26%
1066
May1st to 10thNight
27%
540
25%
1620
15%
540
41%
540
28%
1008
May11th to 20thNight
36%
531
21%
1594
16%
531
45%
531
28%
1002
May21st to endNight
37%
583
20%
1745
12%
582
50%
582
28%
1110
June1st to 10thNight
58%
540
24%
1620
21%
540
67%
540
45%
844
June11th to 20thNight
51%
540
23%
1620
19%
540
61%
540
45%
853
June21st to endNight
59%
540
22%
1620
22%
540
64%
540
36%
948
July1st to 10thNight
64%
525
16%
1575
14%
525
69%
525
32%
967
July11th to 20thNight
75%
522
26%
1566
28%
522
79%
522
47%
814
July21st to endNight
76%
591
23%
1673
24%
558
81%
558
48%
853
August1st to 10thNight
81%
537
28%
1683
29%
534
85%
534
56%
775
August11th to 20thNight
76%
534
24%
1778
26%
534
79%
534
37%
970
August21st to endNight
72%
594
19%
2042
21%
594
74%
594
32%
1165
September1st to 10thNight
67%
540
19%
1980
21%
540
69%
540
30%
1126
September11th to 20thNight
65%
540
21%
1980
22%
540
69%
540
26%
1187
September21st to endNight
67%
540
26%
1980
27%
540
70%
540
31%
1076
October1st to 10thNight
70%
540
33%
1980
33%
540
73%
540
38%
995
October11th to 20thNight
53%
598
31%
2038
23%
598
61%
598
32%
1163
October21st to endNight
45%
792
33%
2376
18%
792
55%
792
37%
1316
November1st to 10thNight
51%
740
28%
2220
18%
740
57%
740
33%
1323
November11th to 20thNight
47%
921
26%
2441
13%
921
53%
921
36%
1476
November21st to endNight
36%
950
27%
2470
12%
950
45%
950
29%
1598
December1st to 10thNight
40%
950
31%
2470
15%
950
49%
950
34%
1528
December11th to 20thNight
32%
950
25%
2900
11%
948
40%
948
23%
1884
December21st to endNight
35%
1038
17%
4305
12%
1026
43%
1026
23%
2349

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
14%5%25%5%3445%7%46%
75033
Night
14%5%24423447%51%
75122
TransparencyDay
37%5%10%20%18%9%
74758
Night
34%5%11%20%19%12%
74917
SeeingDay
16%8%24%31%18%3
13713
Night
17%8%27%35%13%1
23810

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
15%424323336%54%
1707
11th to 20thDay
18%6%24423235%50%
1710
21st to endDay
15%5%24324346%52%
2068
February1st to 10thDay
17%7%35%434246%47%
1800
11th to 20thDay
18%7%25%424346%44%
1749
21st to endDay
18%6%33322345%50%
1480
March1st to 10thDay
20%8%25%434446%42%
1916
11th to 20thDay
17%5%25%433446%45%
1980
21st to endDay
17%6%25%42435%6%47%
2178
April1st to 10thDay
16%7%35%5%33446%45%
1980
11th to 20thDay
21%5%3443345%5%43%
2010
21st to endDay
17%6%35%5%34336%45%
2247
May1st to 10thDay
17%7%35%5%35%5%5%6%40%
2340
11th to 20thDay
17%6%36%6%35%45%6%38%
2302
21st to endDay
18%6%25%5%46%5%7%8%34%
2531
June1st to 10thDay
7%5%245%36%6%6%10%47%
2340
11th to 20thDay
9%6%25%5%35%5%5%8%46%
2340
21st to endDay
10%435%7%47%7%6%9%38%
2340
July1st to 10thDay
14%5%35%6%47%6%6%8%35%
2340
11th to 20thDay
6%3145%26%5%6%10%51%
2340
21st to endDay
6%324446%6%6%11%49%
2546
August1st to 10thDay
321333445%10%62%
2240
11th to 20thDay
8%3245%35%5%6%10%49%
2123
21st to endDay
8%435%7%45%6%7%10%41%
2314
September1st to 10thDay
13%6%36%5%45%5%47%42%
1980
11th to 20thDay
14%6%36%5%35%6%6%8%39%
1980
21st to endDay
9%5%25%435%6%5%7%47%
1980
October1st to 10thDay
8%425%6%35%45%6%53%
1980
11th to 20thDay
14%5%23434446%50%
1904
21st to endDay
13%414423335%57%
1980
November1st to 10thDay
15%7%345%3445%6%45%
1858
11th to 20thDay
14%6%25%5%235%5%5%48%
1734
21st to endDay
18%6%345%24336%45%
1710
December1st to 10thDay
17%6%25%423346%48%
1710
11th to 20thDay
17%7%25%5%24445%45%
2161
21st to endDay
16%6%2332233457%
3135
January1st to 10thNight
16%413323336%54%
2458
11th to 20thNight
16%7%33423345%51%
2470
21st to endNight
17%6%24323345%49%
2530
February1st to 10thNight
16%7%34323445%50%
2160
11th to 20thNight
17%7%24323335%50%
2098
21st to endNight
19%6%24324336%47%
1776
March1st to 10thNight
19%6%25%5%24347%44%
2041
11th to 20thNight
17%8%35%423335%47%
1980
21st to endNight
17%5%24423446%49%
2178
April1st to 10thNight
13%6%26%42435%8%47%
1980
11th to 20thNight
19%6%35%323345%47%
1895
21st to endNight
19%5%25%423335%48%
1710
May1st to 10thNight
15%6%35%43345%5%47%
1620
11th to 20thNight
14%6%245%24448%46%
1593
21st to endNight
17%4245%245%5%9%43%
1745
June1st to 10thNight
7%42332345%8%60%
1620
11th to 20thNight
6%31443335%9%59%
1620
21st to endNight
8%5%2444446%10%49%
1620
July1st to 10thNight
11%5%24335%6%7%9%45%
1620
11th to 20thNight
422332446%8%61%
1620
21st to endNight
5%3133245%6%10%59%
1772
August1st to 10thNight
221121345%9%68%
1693
11th to 20thNight
6%3133346%6%11%54%
1778
21st to endNight
8%5%244345%5%10%49%
2042
September1st to 10thNight
9%5%35%5%25%46%8%49%
1980
11th to 20thNight
11%7%244346%6%8%45%
1980
21st to endNight
9%5%25%425%46%7%51%
1980
October1st to 10thNight
7%41442335%6%59%
1980
11th to 20thNight
14%5%24323445%53%
2038
21st to endNight
15%42332223361%
2376
November1st to 10thNight
14%6%24423325%54%
2220
11th to 20thNight
12%6%24424346%54%
2441
21st to endNight
19%6%23324346%47%
2470
December1st to 10thNight
15%7%24313446%51%
2470
11th to 20thNight
17%8%26%423335%47%
3036
21st to endNight
18%6%24222235%54%
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
34%35%20%21%17%
1708
11th to 20thDay
41%26%15%21%17%
1710
21st to endDay
36%36%14%26%15%
2068
February1st to 10thDay
42%36%12%22%16%
1800
11th to 20thDay
42%46%17%17%14%
1759
21st to endDay
38%37%17%19%17%
1480
March1st to 10thDay
45%48%13%18%11%
1916
11th to 20thDay
40%47%15%16%17%
1980
21st to endDay
40%39%17%19%13%
2178
April1st to 10thDay
42%49%17%17%11%
1980
11th to 20thDay
43%5%6%17%18%12%
2010
21st to endDay
42%45%19%18%11%
2247
May1st to 10thDay
45%5%8%16%19%7%
2340
11th to 20thDay
45%6%9%19%18%4
2306
21st to endDay
46%7%10%21%14%1
2531
June1st to 10thDay
32%8%12%26%20%3
2340
11th to 20thDay
35%6%11%26%18%4
2340
21st to endDay
42%7%11%23%14%4
2340
July1st to 10thDay
42%9%14%24%10%1
2276
11th to 20thDay
27%7%17%28%18%2
2271
21st to endDay
25%9%19%33%13%1
2405
August1st to 10thDay
19%416%40%19%1
2226
11th to 20thDay
29%7%17%31%12%4
2123
21st to endDay
36%8%16%24%13%3
2314
September1st to 10thDay
41%6%10%19%16%7%
1980
11th to 20thDay
41%8%11%19%17%5%
1980
21st to endDay
34%6%10%21%18%11%
1980
October1st to 10thDay
31%5%10%20%25%9%
1980
11th to 20thDay
36%49%16%19%16%
1904
21st to endDay
31%5%5%15%25%20%
1980
November1st to 10thDay
41%47%20%17%11%
1858
11th to 20thDay
37%47%16%20%15%
1734
21st to endDay
42%45%15%20%14%
1710
December1st to 10thDay
39%37%21%20%10%
1710
11th to 20thDay
41%5%7%10%20%17%
2159
21st to endDay
34%26%14%28%16%
3135
January1st to 10thNight
33%37%16%22%19%
2458
11th to 20thNight
38%26%16%21%17%
2470
21st to endNight
38%35%14%22%18%
2530
February1st to 10thNight
38%46%13%21%18%
2160
11th to 20thNight
39%26%16%19%17%
2098
21st to endNight
40%46%16%18%17%
1776
March1st to 10thNight
42%39%16%19%11%
2041
11th to 20thNight
42%37%13%16%17%
1980
21st to endNight
37%311%16%17%15%
2178
April1st to 10thNight
37%310%20%16%14%
1980
11th to 20thNight
41%49%14%17%16%
1895
21st to endNight
41%47%20%17%10%
1710
May1st to 10thNight
39%5%10%20%16%10%
1620
11th to 20thNight
38%6%10%24%17%5%
1594
21st to endNight
39%6%15%25%13%2
1746
June1st to 10thNight
23%5%17%31%21%3
1620
11th to 20thNight
24%5%16%31%20%5%
1620
21st to endNight
31%6%18%27%15%3
1620
July1st to 10thNight
32%10%20%28%9%1
1575
11th to 20thNight
19%8%21%29%20%2
1566
21st to endNight
18%8%28%35%10%1
1673
August1st to 10thNight
14%6%22%40%17%1
1683
11th to 20thNight
24%10%21%31%11%3
1778
21st to endNight
30%9%22%26%11%3
2042
September1st to 10thNight
34%6%16%21%16%7%
1980
11th to 20thNight
36%8%16%21%14%5%
1980
21st to endNight
31%7%12%22%18%11%
1980
October1st to 10thNight
26%5%12%25%20%11%
1980
11th to 20thNight
33%5%9%16%19%17%
2038
21st to endNight
30%36%16%24%22%
2376
November1st to 10thNight
35%47%19%22%13%
2220
11th to 20thNight
33%49%19%20%16%
2441
21st to endNight
39%47%15%20%14%
2470
December1st to 10thNight
35%38%19%21%13%
2470
11th to 20thNight
42%35%12%18%20%
3037
21st to endNight
36%25%13%28%15%
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
22%19%36%19%4
270
11th to 20thDay
27%14%33%20%6%
270
21st to endDay
22%16%38%20%4
294
February1st to 10thDay
25%19%30%22%4
240
11th to 20thDay
28%20%38%11%3
240
21st to endDay
29%22%38%10%2
198
March1st to 10thDay
22%18%45%14%
240
11th to 20thDay
22%20%40%14%4
240
21st to endDay
22%17%42%15%21
264
April1st to 10thDay
24%17%44%14%2
240
11th to 20thDay
24%17%35%20%3
288
21st to endDay
20%16%42%20%3
507
May1st to 10thDay
21%11%38%24%5%
603
11th to 20thDay
20%9%30%33%6%1
625
21st to endDay
20%5%32%30%12%1
679
June1st to 10thDay
9%320%45%20%3
630
11th to 20thDay
9%322%47%16%3
630
21st to endDay
9%417%40%26%5%
630
July1st to 10thDay
12%213%38%28%7%
621
11th to 20thDay
6%8%43%38%4
618
21st to endDay
5%26%42%38%7%
684
August1st to 10thDay
315%47%38%6%
538
11th to 20thDay
7%26%42%35%8%
437
21st to endDay
6%35%37%39%11%
433
September1st to 10thDay
14%16%30%39%9%
270
11th to 20thDay
10%16%34%40%9%
270
21st to endDay
9%210%37%34%8%
270
October1st to 10thDay
7%318%41%26%5%
270
11th to 20thDay
12%429%37%16%3
270
21st to endDay
22%11%29%23%13%2
297
November1st to 10thDay
20%5%32%30%11%2
270
11th to 20thDay
23%10%31%24%9%3
270
21st to endDay
29%18%30%15%7%1
270
December1st to 10thDay
17%11%36%26%9%2
270
11th to 20thDay
23%17%35%19%6%
270
21st to endDay
23%13%35%24%41
297
January1st to 10thNight
20%10%30%31%8%
950
11th to 20thNight
22%13%29%29%6%
950
21st to endNight
22%11%31%29%6%
862
February1st to 10thNight
23%14%32%25%6%
720
11th to 20thNight
26%13%33%25%3
704
21st to endNight
27%13%39%19%1
592
March1st to 10thNight
25%10%37%25%2
601
11th to 20thNight
23%9%39%25%4
540
21st to endNight
18%13%44%22%4
594
April1st to 10thNight
15%12%44%25%4
540
11th to 20thNight
23%11%40%24%2
533
21st to endNight
20%10%45%19%5%1
540
May1st to 10thNight
18%11%42%27%3
540
11th to 20thNight
17%8%36%31%7%1
531
21st to endNight
17%6%35%32%9%
584
June1st to 10thNight
8%129%44%17%1
540
11th to 20thNight
7%136%45%10%1
540
21st to endNight
8%224%45%18%3
540
July1st to 10thNight
11%217%46%22%2
525
11th to 20thNight
4113%58%22%2
522
21st to endNight
5%111%58%23%3
591
August1st to 10thNight
2112%55%27%2
537
11th to 20thNight
5%29%52%28%3
534
21st to endNight
8%26%47%32%4
594
September1st to 10thNight
10%110%44%30%4
540
11th to 20thNight
14%29%39%33%3
540
21st to endNight
12%210%40%31%5%
540
October1st to 10thNight
9%114%48%24%4
540
11th to 20thNight
16%5%22%38%18%2
598
21st to endNight
17%8%27%27%19%2
792
November1st to 10thNight
16%6%22%39%16%2
740
11th to 20thNight
16%7%25%37%14%1
921
21st to endNight
23%11%25%29%11%1
950
December1st to 10thNight
20%9%28%33%9%1
950
11th to 20thNight
25%10%28%30%7%
950
21st to endNight
20%10%29%33%7%
1045
Page generated at 2024-01-28 04:26:38. Version ac07

Copyright 2024 Attilla Danko


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