Bastrop State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bastrop State Park clear sky chart from 2005-11-05 to 2017-09-21.

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
51%
15423
26%
46983
18%
15379
59%
15379
34%
26939

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
38%
897
26%
2327
12%
895
45%
895
32%
1487
January16th to endNight
36%
933
29%
2469
12%
933
46%
933
32%
1547
February1st to 15thNight
37%
704
27%
2106
13%
698
47%
698
29%
1253
February16th to endNight
27%
611
28%
1873
10%
611
41%
611
29%
1110
March1st to 15thNight
30%
540
26%
1980
13%
540
46%
540
25%
1157
March16th to endNight
34%
576
24%
2112
15%
576
46%
576
26%
1189
April1st to 15thNight
30%
539
23%
1977
13%
539
45%
539
26%
1116
April16th to endNight
30%
540
25%
1789
15%
540
46%
540
29%
1056
May1st to 15thNight
35%
539
22%
1620
16%
539
44%
539
31%
979
May16th to endNight
51%
561
26%
1684
22%
561
60%
561
38%
946
June1st to 15thNight
72%
540
23%
1620
24%
540
77%
540
51%
796
June16th to endNight
72%
540
21%
1620
22%
540
76%
540
37%
929
July1st to 15thNight
77%
510
21%
1530
25%
510
79%
510
45%
810
July16th to endNight
83%
564
24%
1594
27%
531
85%
531
47%
836
August1st to 15thNight
88%
539
28%
1610
31%
536
89%
536
56%
762
August16th to endNight
78%
573
19%
2000
23%
573
79%
573
32%
1117
September1st to 15thNight
77%
540
21%
1980
24%
540
79%
540
35%
1066
September16th to endNight
71%
510
26%
1881
27%
510
74%
510
30%
1047
October1st to 15thNight
70%
536
35%
1856
32%
536
75%
536
43%
905
October16th to endNight
60%
704
36%
2112
24%
704
66%
704
48%
1064
November1st to 15thNight
53%
700
29%
2100
20%
700
59%
700
37%
1189
November16th to endNight
48%
867
31%
2307
17%
867
55%
867
39%
1351
December1st to 15thNight
39%
900
27%
2340
14%
900
45%
900
28%
1569
December16th to endNight
38%
960
23%
2496
11%
960
45%
960
28%
1658

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
11%5%25%5%35%45%7%44%
47867
Night
10%423323347%51%
47185
TransparencyDay
38%5%10%19%17%8%
47567
Night
31%412%21%18%10%
46990
SeeingDay
11%416%28%29%10%
5397
Night
13%6%24%36%18%1
15429

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 15thDay
18%424324336%45%
1611
16th to endDay
16%6%1432323451%
1764
February1st to 15thDay
17%5%14313335%50%
1750
16th to endDay
16%7%34323345%46%
1600
March1st to 15thDay
20%7%35%414345%40%
1980
16th to endDay
15%6%24423336%46%
2110
April1st to 15thDay
11%7%35%5%2445%6%41%
1971
16th to endDay
13%7%26%42445%6%42%
2166
May1st to 15thDay
13%6%27%5%35%5%5%6%37%
2331
16th to endDay
10%6%36%6%35%5%7%8%36%
2430
June1st to 15thDay
5%3245%36%6%7%10%45%
2340
16th to endDay
7%5%36%6%5%7%6%7%10%34%
2340
July1st to 15thDay
7%325%5%46%7%8%10%37%
2340
16th to endDay
5%4246%47%6%7%11%39%
2466
August1st to 15thDay
3112435%5%7%11%53%
2340
16th to endDay
7%426%6%36%7%7%10%36%
2198
September1st to 15thDay
7%5%36%8%36%5%6%7%39%
1980
16th to endDay
8%425%5%37%6%5%6%43%
1871
October1st to 15thDay
9%423424448%51%
1763
16th to endDay
8%3322323465%
1760
November1st to 15thDay
10%5%34425%5%46%47%
1758
16th to endDay
13%6%2332332453%
1650
December1st to 15thDay
20%6%26%323346%40%
1620
16th to endDay
16%6%35%5%24446%40%
1728
January1st to 15thNight
18%424213336%48%
2327
16th to endNight
17%5%23323335%49%
2469
February1st to 15thNight
16%6%23211235%51%
2102
16th to endNight
14%5%23323335%50%
1873
March1st to 15thNight
17%5%24313345%47%
1980
16th to endNight
11%5%34324247%49%
2112
April1st to 15thNight
10%6%25%42335%7%48%
1977
16th to endNight
13%5%35%422447%46%
1789
May1st to 15thNight
8%5%25%5%245%5%9%44%
1619
16th to endNight
7%3234245%6%10%49%
1683
June1st to 15thNight
22231345%11%61%
1620
16th to endNight
4324335%5%6%9%51%
1620
July1st to 15thNight
5%22332436%10%56%
1620
16th to endNight
421232445%12%56%
1702
August1st to 15thNight
1212235%5%10%64%
1620
16th to endNight
5%3234345%7%12%46%
2000
September1st to 15thNight
6%4135%3446%9%50%
1980
16th to endNight
8%4145%3446%6%49%
1881
October1st to 15thNight
6%313323246%61%
1856
16th to endNight
8%313222235%65%
2112
November1st to 15thNight
9%423423447%52%
2100
16th to endNight
13%423322235%56%
2307
December1st to 15thNight
15%7%34323335%45%
2340
16th to endNight
17%7%34423345%44%
2496

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
40%26%16%21%11%
1612
16th to endDay
37%25%15%23%15%
1764
February1st to 15thDay
38%26%16%20%15%
1751
16th to endDay
40%36%16%20%12%
1600
March1st to 15thDay
46%26%11%20%11%
1980
16th to endDay
41%36%16%22%8%
2112
April1st to 15thDay
42%37%17%17%11%
1971
16th to endDay
42%46%19%16%9%
2166
May1st to 15thDay
45%6%9%15%15%8%
2331
16th to endDay
42%6%11%19%15%4
2434
June1st to 15thDay
32%6%12%23%21%3
2340
16th to endDay
41%9%12%20%13%2
2340
July1st to 15thDay
36%7%17%25%11%1
2201
16th to endDay
34%7%20%27%9%
2311
August1st to 15thDay
22%7%18%34%15%1
2326
16th to endDay
39%8%17%22%8%2
2198
September1st to 15thDay
40%6%12%20%14%5%
1980
16th to endDay
37%6%9%19%17%10%
1871
October1st to 15thDay
31%49%18%19%15%
1763
16th to endDay
24%2416%30%19%
1760
November1st to 15thDay
36%49%20%18%11%
1758
16th to endDay
36%26%12%22%20%
1650
December1st to 15thDay
46%27%17%17%8%
1620
16th to endDay
45%38%15%17%9%
1728
January1st to 15thNight
38%25%16%20%15%
2327
16th to endNight
37%2416%21%16%
2469
February1st to 15thNight
36%25%14%20%18%
2112
16th to endNight
37%25%18%20%15%
1873
March1st to 15thNight
39%39%14%19%12%
1980
16th to endNight
35%410%16%22%10%
2112
April1st to 15thNight
35%410%16%18%13%
1977
16th to endNight
37%311%20%15%11%
1789
May1st to 15thNight
35%5%12%21%16%9%
1620
16th to endNight
27%6%17%29%15%3
1685
June1st to 15thNight
17%6%17%28%26%3
1620
16th to endNight
27%8%16%29%15%2
1620
July1st to 15thNight
22%6%24%35%11%
1530
16th to endNight
19%7%28%35%8%
1594
August1st to 15thNight
13%7%26%37%14%
1610
16th to endNight
28%9%24%26%8%2
2000
September1st to 15thNight
28%6%20%24%14%5%
1980
16th to endNight
31%6%14%20%17%9%
1881
October1st to 15thNight
23%411%25%20%14%
1856
16th to endNight
23%25%19%27%22%
2112
November1st to 15thNight
31%311%22%19%12%
2100
16th to endNight
32%27%15%20%22%
2307
December1st to 15thNight
42%37%18%18%8%
2340
16th to endNight
42%25%16%20%11%
2496

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
16%436%33%7%1
90
16th to endDay
19%15%32%19%11%1
96
February1st to 15thDay
15%13%35%21%14%
90
16th to endDay
18%17%32%23%7%1
81
March1st to 15thDay
28%13%27%15%12%2
90
16th to endDay
14%5%31%29%16%3
96
April1st to 15thDay
13%8%36%27%11%2
90
16th to endDay
19%6%34%27%11%1
276
May1st to 15thDay
14%8%33%30%11%
468
16th to endDay
16%8%24%31%17%2
517
June1st to 15thDay
6%18%42%32%8%
495
16th to endDay
7%39%33%32%14%
495
July1st to 15thDay
5%17%31%41%12%
475
16th to endDay
41223%49%18%
515
August1st to 15thDay
4217%53%21%
493
16th to endDay
14%25%27%26%23%
238
September1st to 15thDay
2223%49%20%
135
16th to endDay
420%43%30%
105
October1st to 15thDay
15%34%47%11%
90
16th to endDay
18%11%29%31%9%
96
November1st to 15thDay
21%324%32%12%6%
90
16th to endDay
20%11%28%23%10%6%
90
December1st to 15thDay
28%125%21%13%10%
90
16th to endDay
26%16%28%19%8%1
96
January1st to 15thNight
20%9%27%32%10%
900
16th to endNight
20%9%29%32%7%
933
February1st to 15thNight
20%10%29%33%6%
704
16th to endNight
18%10%42%25%4
611
March1st to 15thNight
20%7%38%28%4
540
16th to endNight
12%10%38%31%5%
576
April1st to 15thNight
12%9%43%30%3
539
16th to endNight
15%7%41%25%8%
540
May1st to 15thNight
10%7%42%31%6%
540
16th to endNight
7%332%40%15%
563
June1st to 15thNight
316%52%25%1
540
16th to endNight
4213%47%28%4
540
July1st to 15thNight
48%48%34%2
510
16th to endNight
41446%39%4
564
August1st to 15thNight
2251%37%5%
539
16th to endNight
6%340%42%5%
573
September1st to 15thNight
7%5%36%44%5%
540
16th to endNight
9%18%30%43%6%
510
October1st to 15thNight
7%314%43%25%5%
536
16th to endNight
9%5%21%36%23%2
704
November1st to 15thNight
11%326%36%20%1
700
16th to endNight
15%7%23%34%17%1
867
December1st to 15thNight
21%8%26%31%12%
900
16th to endNight
20%10%26%31%9%
960
Page generated at 2017-09-22 06:35:29. Version ac04

Copyright 2017 A. Danko


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