Texas Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Texas Star Party clear sky chart from 2005-11-05 to

2017-09-12
.

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%
15387
32%
47007
23%
15346
70%
15346
44%
24141

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 15thNight
50%
716
35%
2148
20%
716
64%
716
42%
1135
January16th to endNight
51%
768
38%
2304
24%
768
65%
768
44%
1174
February1st to 15thNight
54%
701
36%
2107
21%
696
69%
696
50%
1016
February16th to endNight
43%
632
35%
1894
18%
632
59%
632
49%
912
March1st to 15thNight
51%
720
34%
2139
20%
720
63%
720
46%
1071
March16th to endNight
50%
651
38%
1995
22%
651
65%
651
48%
961
April1st to 15thNight
47%
539
34%
1798
21%
539
65%
539
42%
865
April16th to endNight
51%
540
36%
1800
27%
540
69%
540
50%
790
May1st to 15thNight
50%
539
28%
1799
22%
539
64%
539
43%
875
May16th to endNight
62%
561
26%
1760
24%
561
70%
561
40%
934
June1st to 15thNight
74%
540
25%
1620
23%
540
79%
540
49%
808
June16th to endNight
77%
540
25%
1620
25%
540
79%
540
43%
871
July1st to 15thNight
78%
510
19%
1688
23%
510
78%
510
37%
928
July16th to endNight
81%
564
22%
1771
26%
531
81%
531
35%
979
August1st to 15thNight
84%
539
23%
1789
30%
536
85%
536
41%
920
August16th to endNight
79%
573
21%
1910
24%
573
80%
573
29%
1141
September1st to 15thNight
76%
530
19%
1774
22%
530
76%
530
31%
1039
September16th to endNight
76%
492
25%
1815
28%
492
77%
492
31%
1014
October1st to 15thNight
72%
514
33%
1834
34%
514
75%
514
42%
884
October16th to endNight
71%
704
37%
2112
27%
704
77%
704
56%
992
November1st to 15thNight
65%
784
38%
2184
24%
784
72%
784
60%
1027
November16th to endNight
61%
900
38%
2340
21%
900
70%
900
54%
1207
December1st to 15thNight
56%
900
37%
2340
21%
900
65%
900
48%
1288
December16th to endNight
47%
930
38%
2466
18%
930
60%
930
47%
1310

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
5%31332445%7%56%
47614
Night
431332445%7%59%
47232
Cloud CoverDay
5%3134245%5%7%55%
47612
Night
431332445%7%59%
47232
TransparencyDay
24%5%8%17%24%18%
47334
Night
22%5%9%18%24%19%
47014
SeeingDay
6%7%21%30%25%8%
5227
Night
5%5%21%37%27%3
15397

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 15thDay
5%5%13323337%59%
1790
16th to endDay
43132235%35%63%
1920
February1st to 15thDay
2212123445%68%
1750
16th to endDay
121221235%7%69%
1580
March1st to 15thDay
232443445%6%59%
1818
16th to endDay
2312323346%65%
2229
April1st to 15thDay
232232445%6%63%
2150
16th to endDay
222212336%71%
2160
May1st to 15thDay
3312224346%64%
2151
16th to endDay
5%2122245%5%8%61%
2351
June1st to 15thDay
11123236%7%7%62%
2340
16th to endDay
5%313435%6%8%9%47%
2340
July1st to 15thDay
10%325%447%8%6%8%36%
2167
16th to endDay
7%5%246%5%8%8%6%10%33%
2277
August1st to 15thDay
6%3145%47%8%8%11%36%
2160
16th to endDay
8%5%36%7%48%6%6%9%33%
2292
September1st to 15thDay
13%6%25%6%47%5%6%7%34%
2104
16th to endDay
9%6%15%6%345%6%6%45%
1815
October1st to 15thDay
6%214314336%61%
1793
16th to endDay
422223235%70%
1760
November1st to 15thDay
431231233468%
1660
16th to endDay
5%31321213470%
1620
December1st to 15thDay
4313314346%62%
1620
16th to endDay
3413213447%61%
1767
January1st to 15thNight
4424324345%60%
2148
16th to endNight
5%223314347%61%
2304
February1st to 15thNight
2313223346%65%
2102
16th to endNight
3212224446%66%
1894
March1st to 15thNight
431332345%7%61%
2139
16th to endNight
3323313345%66%
1995
April1st to 15thNight
4213414446%63%
1798
16th to endNight
221222333470%
1800
May1st to 15thNight
42133235%46%62%
1799
16th to endNight
5%113325%46%8%55%
1759
June1st to 15thNight
21124246%7%8%57%
1620
16th to endNight
4213435%6%8%10%50%
1620
July1st to 15thNight
4214435%6%7%10%48%
1788
16th to endNight
4224425%6%7%12%45%
1891
August1st to 15thNight
3312435%6%8%16%45%
1800
16th to endNight
5%3145%36%6%8%11%43%
1910
September1st to 15thNight
8%413425%6%7%10%43%
1774
16th to endNight
7%424325%6%7%7%47%
1815
October1st to 15thNight
6%313323446%61%
1834
16th to endNight
321312345%71%
2112
November1st to 15thNight
322213245%71%
2184
16th to endNight
421331223469%
2340
December1st to 15thNight
4213423446%62%
2340
16th to endNight
341322333465%
2466

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 15thDay
45%23424336%59%
1790
16th to endDay
4413323436%62%
1920
February1st to 15thDay
22122235%45%67%
1750
16th to endDay
1212212347%68%
1580
March1st to 15thDay
232442445%6%58%
1818
16th to endDay
2312324346%64%
2227
April1st to 15thDay
2312324446%63%
2150
16th to endDay
232212346%71%
2160
May1st to 15thDay
3212314446%63%
2151
16th to endDay
5%21222446%7%60%
2351
June1st to 15thDay
11133246%7%8%60%
2340
16th to endDay
5%3235%35%6%7%10%47%
2340
July1st to 15thDay
9%4245%47%9%6%8%35%
2167
16th to endDay
6%425%6%5%9%7%7%10%32%
2277
August1st to 15thDay
6%3146%37%8%9%12%35%
2160
16th to endDay
8%5%27%7%5%7%7%5%8%33%
2292
September1st to 15thDay
13%6%25%6%46%5%7%7%33%
2104
16th to endDay
10%5%15%6%35%5%6%7%43%
1815
October1st to 15thDay
6%313323346%60%
1793
16th to endDay
422222335%69%
1760
November1st to 15thDay
4312212335%68%
1660
16th to endDay
5%312212135%69%
1620
December1st to 15thDay
4323314336%62%
1620
16th to endDay
341321345%7%60%
1767
January1st to 15thNight
45%24324346%59%
2148
16th to endNight
5%323314347%60%
2304
February1st to 15thNight
2213223437%65%
2102
16th to endNight
322323446%66%
1894
March1st to 15thNight
431322435%6%61%
2139
16th to endNight
3323323345%65%
1995
April1st to 15thNight
4313323436%63%
1798
16th to endNight
221222333470%
1800
May1st to 15thNight
3314323446%62%
1799
16th to endNight
5%113416%46%8%55%
1759
June1st to 15thNight
21134246%7%9%56%
1620
16th to endNight
4213326%6%8%10%50%
1620
July1st to 15thNight
4323435%6%7%10%47%
1788
16th to endNight
4314436%6%7%12%45%
1891
August1st to 15thNight
32133346%8%16%44%
1800
16th to endNight
43145%36%6%8%12%42%
1910
September1st to 15thNight
8%414435%6%6%11%43%
1774
16th to endNight
7%424325%6%7%8%46%
1815
October1st to 15thNight
6%213323347%61%
1834
16th to endNight
3211312345%70%
2112
November1st to 15thNight
3212212345%70%
2184
16th to endNight
4313312235%68%
2340
December1st to 15thNight
4213423446%61%
2340
16th to endNight
341322334465%
2466

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 15thDay
26%35%17%30%17%
1791
16th to endDay
21%35%14%32%21%
1920
February1st to 15thDay
16%46%14%26%31%
1751
16th to endDay
15%2415%34%27%
1580
March1st to 15thDay
22%35%16%26%24%
1818
16th to endDay
19%25%11%29%30%
2229
April1st to 15thDay
20%46%9%29%30%
2150
16th to endDay
14%249%34%34%
2160
May1st to 15thDay
19%45%12%25%31%
2151
16th to endDay
18%5%8%17%23%25%
2354
June1st to 15thDay
15%5%11%20%26%20%
2340
16th to endDay
27%7%12%20%20%11%
2340
July1st to 15thDay
37%9%13%22%14%1
2038
16th to endDay
37%11%16%25%8%1
2134
August1st to 15thDay
33%10%17%25%12%1
2147
16th to endDay
42%10%15%17%11%2
2292
September1st to 15thDay
42%10%13%18%11%3
2104
16th to endDay
35%6%10%19%20%7%
1815
October1st to 15thDay
21%6%9%23%21%17%
1793
16th to endDay
17%2416%29%29%
1760
November1st to 15thDay
17%36%19%28%23%
1660
16th to endDay
18%25%15%32%26%
1620
December1st to 15thDay
21%35%18%31%18%
1620
16th to endDay
20%45%21%32%15%
1767
January1st to 15thNight
26%35%15%29%20%
2148
16th to endNight
22%3415%33%19%
2304
February1st to 15thNight
18%36%11%26%33%
2112
16th to endNight
19%25%10%32%30%
1894
March1st to 15thNight
21%35%15%27%26%
2139
16th to endNight
20%2414%28%29%
1995
April1st to 15thNight
22%36%11%28%27%
1798
16th to endNight
16%35%12%25%35%
1800
May1st to 15thNight
21%45%15%21%30%
1800
16th to endNight
23%7%9%17%18%22%
1761
June1st to 15thNight
17%7%14%23%24%12%
1620
16th to endNight
23%7%16%20%19%12%
1620
July1st to 15thNight
25%9%17%30%15%2
1688
16th to endNight
25%10%19%30%12%1
1771
August1st to 15thNight
21%8%23%28%17%
1789
16th to endNight
31%11%16%25%12%2
1910
September1st to 15thNight
29%10%19%23%11%4
1774
16th to endNight
30%7%15%20%18%7%
1815
October1st to 15thNight
22%5%11%23%19%17%
1834
16th to endNight
16%35%13%28%31%
2112
November1st to 15thNight
14%26%18%34%22%
2184
16th to endNight
18%2413%30%30%
2340
December1st to 15thNight
22%35%19%28%19%
2340
16th to endNight
22%2418%34%17%
2466

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 15thDay
8%20%34%25%11%
90
16th to endDay
9%26%26%23%9%5%
96
February1st to 15thDay
410%23%24%35%2
90
16th to endDay
8%18%28%27%14%2
81
March1st to 15thDay
444%33%12%3
108
16th to endDay
315%46%21%10%3
288
April1st to 15thDay
418%44%22%9%
269
16th to endDay
221%42%25%6%1
270
May1st to 15thDay
315%40%33%6%
288
16th to endDay
5%435%36%15%2
438
June1st to 15thDay
1112%43%34%6%
495
16th to endDay
5%16%35%41%9%
495
July1st to 15thDay
8%332%36%17%
312
16th to endDay
7%1428%40%18%
327
August1st to 15thDay
8%219%45%22%
315
16th to endDay
11%1426%37%17%
332
September1st to 15thDay
10%26%30%35%15%
291
16th to endDay
10%210%30%34%13%
90
October1st to 15thDay
18%216%24%25%12%
90
16th to endDay
5%320%28%23%18%
96
November1st to 15thDay
14%10%24%22%20%8%
90
16th to endDay
13%13%30%27%12%3
90
December1st to 15thDay
10%7%26%38%15%1
90
16th to endDay
8%17%35%29%9%
96
January1st to 15thNight
6%5%32%36%16%2
720
16th to endNight
6%9%28%38%16%1
768
February1st to 15thNight
38%29%35%20%1
704
16th to endNight
48%39%35%10%
632
March1st to 15thNight
49%29%36%18%1
720
16th to endNight
39%30%38%15%1
651
April1st to 15thNight
5%9%33%39%10%
539
16th to endNight
37%33%43%11%
540
May1st to 15thNight
5%5%33%42%12%1
540
16th to endNight
4424%46%20%
563
June1st to 15thNight
215%52%27%1
540
16th to endNight
5%17%47%36%2
540
July1st to 15thNight
45%37%49%3
510
16th to endNight
4234%52%4
564
August1st to 15thNight
220%65%9%
539
16th to endNight
5%125%60%6%
573
September1st to 15thNight
8%1224%54%7%
530
16th to endNight
8%15%36%42%5%
492
October1st to 15thNight
7%111%42%33%3
514
16th to endNight
5%315%34%31%9%
704
November1st to 15thNight
4222%34%29%5%
784
16th to endNight
5%6%20%38%25%3
900
December1st to 15thNight
6%5%26%39%18%3
900
16th to endNight
6%10%30%36%13%2
930
Page generated at 2017-09-13 06:39:18. Version ac04

Copyright 2017 A. Danko


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