Abilene State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Abilene State Park clear sky chart from 2005-11-05 to 2018-01-12.

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
49%
16060
31%
48394
19%
16018
61%
16018
43%
25238

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
40%
953
32%
2472
14%
951
52%
951
44%
1391
January16th to endNight
38%
849
38%
2385
14%
849
56%
849
46%
1231
February1st to 15thNight
36%
704
31%
2111
14%
700
51%
700
38%
1146
February16th to endNight
26%
632
33%
1894
10%
632
45%
632
40%
983
March1st to 15thNight
30%
639
30%
2079
12%
639
47%
639
33%
1130
March16th to endNight
31%
576
29%
2112
17%
576
49%
576
36%
1028
April1st to 15thNight
24%
539
28%
1873
10%
539
48%
539
36%
926
April16th to endNight
29%
540
31%
1755
14%
540
52%
540
42%
883
May1st to 15thNight
31%
539
25%
1620
14%
539
48%
539
37%
911
May16th to endNight
45%
561
27%
1684
17%
561
61%
561
44%
902
June1st to 15thNight
56%
540
24%
1620
18%
540
67%
540
51%
792
June16th to endNight
66%
540
29%
1620
28%
540
72%
540
50%
818
July1st to 15thNight
76%
510
24%
1530
25%
510
79%
510
48%
791
July16th to endNight
88%
564
35%
1594
40%
531
89%
531
59%
734
August1st to 15thNight
88%
539
32%
1735
40%
536
88%
536
54%
796
August16th to endNight
80%
573
28%
1910
32%
573
82%
573
42%
972
September1st to 15thNight
72%
540
25%
1955
27%
540
76%
540
35%
1030
September16th to endNight
66%
537
31%
1980
30%
537
72%
537
35%
1041
October1st to 15thNight
60%
540
36%
1980
30%
540
70%
540
45%
903
October16th to endNight
57%
720
40%
2256
25%
720
67%
720
53%
1042
November1st to 15thNight
50%
935
30%
2455
13%
935
58%
935
50%
1307
November16th to endNight
44%
975
37%
2535
15%
975
56%
975
46%
1401
December1st to 15thNight
42%
975
35%
2535
15%
975
53%
975
44%
1459
December16th to endNight
37%
1040
31%
2704
13%
1040
49%
1040
38%
1621

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
7%413323446%56%
48933
Night
6%313323347%60%
48591
Cloud CoverDay
7%413323446%56%
48931
Night
6%313323347%60%
48591
TransparencyDay
27%49%21%24%11%
48631
Night
23%49%22%25%15%
48396
SeeingDay
9%423%32%24%6%
5865
Night
8%6%32%35%15%
16066

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
8%424423235%57%
1710
16th to endDay
9%4223125%5%5%56%
1848
February1st to 15thDay
6%413322345%61%
1750
16th to endDay
9%5%1331222461%
1580
March1st to 15thDay
9%6%24323246%53%
1879
16th to endDay
7%433423335%58%
2112
April1st to 15thDay
5%32242435%6%58%
2072
16th to endDay
8%42342333459%
2202
May1st to 15thDay
10%5%24423345%53%
2331
16th to endDay
7%5%244245%5%7%49%
2430
June1st to 15thDay
5%21332345%5%62%
2340
16th to endDay
6%2134245%5%9%54%
2340
July1st to 15thDay
6%313435%5%6%11%47%
2340
16th to endDay
2213335%5%6%8%56%
2466
August1st to 15thDay
22134245%5%8%59%
2212
16th to endDay
5%3145%46%5%7%9%45%
2292
September1st to 15thDay
9%415%5%25%45%7%48%
2004
16th to endDay
12%41432345%5%53%
1980
October1st to 15thDay
6%313222336%62%
1980
16th to endDay
5%31221232372%
1953
November1st to 15thDay
5%412313346%62%
1730
16th to endDay
7%32221223467%
1755
December1st to 15thDay
10%6%14322236%56%
1755
16th to endDay
9%5%23424346%51%
1872
January1st to 15thNight
8%41431223462%
2472
16th to endNight
8%312212345%64%
2385
February1st to 15thNight
7%42431323460%
2102
16th to endNight
9%312222335%61%
1894
March1st to 15thNight
9%423323445%56%
2079
16th to endNight
7%323313336%61%
2112
April1st to 15thNight
5%31341335%6%59%
1873
16th to endNight
5%312223447%62%
1755
May1st to 15thNight
6%324424447%55%
1619
16th to endNight
431321446%10%56%
1683
June1st to 15thNight
311232346%9%62%
1620
16th to endNight
311322336%10%61%
1620
July1st to 15thNight
411332445%11%57%
1620
16th to endNight
211122345%13%62%
1702
August1st to 15thNight
12133125%5%9%64%
1745
16th to endNight
431332346%10%57%
1910
September1st to 15thNight
8%31342445%8%52%
1955
16th to endNight
8%4133335%5%7%53%
1980
October1st to 15thNight
5%212212346%65%
1980
16th to endNight
431221223472%
2256
November1st to 15thNight
5%213323325%66%
2455
16th to endNight
7%31432234463%
2535
December1st to 15thNight
9%423312247%57%
2535
16th to endNight
8%4243245%45%54%
2704

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
8%414423335%57%
1710
16th to endDay
9%41332245%5%56%
1848
February1st to 15thDay
6%5%13222346%62%
1750
16th to endDay
9%5%2331222462%
1580
March1st to 15thDay
10%5%24313346%53%
1879
16th to endDay
7%423413335%58%
2110
April1st to 15thDay
5%323423446%58%
2072
16th to endDay
8%413433335%59%
2202
May1st to 15thDay
9%5%24423346%53%
2331
16th to endDay
7%324415%5%5%8%50%
2430
June1st to 15thDay
5%21332335%6%62%
2340
16th to endDay
6%2133245%5%9%55%
2340
July1st to 15thDay
6%313435%5%6%11%48%
2340
16th to endDay
2213336%5%6%8%56%
2466
August1st to 15thDay
2213425%45%9%58%
2212
16th to endDay
6%3145%36%6%7%9%45%
2292
September1st to 15thDay
9%4145%25%5%5%7%48%
2004
16th to endDay
11%41432345%5%53%
1980
October1st to 15thDay
6%313323335%63%
1980
16th to endDay
421221232272%
1953
November1st to 15thDay
5%312323346%63%
1730
16th to endDay
7%31321223467%
1755
December1st to 15thDay
9%6%14313246%56%
1755
16th to endDay
8%6%14424446%52%
1872
January1st to 15thNight
8%413312235%62%
2472
16th to endNight
7%31221234464%
2385
February1st to 15thNight
7%43432323460%
2102
16th to endNight
9%312222336%61%
1894
March1st to 15thNight
8%5%1332433457%
2079
16th to endNight
6%323313346%61%
2112
April1st to 15thNight
5%31332335%7%60%
1873
16th to endNight
5%313213347%62%
1755
May1st to 15thNight
5%314424348%56%
1619
16th to endNight
421322346%10%56%
1683
June1st to 15thNight
31231346%9%62%
1620
16th to endNight
321322436%9%61%
1620
July1st to 15thNight
411332346%11%57%
1620
16th to endNight
21121345%13%62%
1702
August1st to 15thNight
12232345%9%64%
1745
16th to endNight
431232346%10%56%
1910
September1st to 15thNight
8%213325%46%8%52%
1955
16th to endNight
9%31442345%7%52%
1980
October1st to 15thNight
5%312312346%65%
1980
16th to endNight
331222223471%
2256
November1st to 15thNight
5%212323335%66%
2455
16th to endNight
7%21432234463%
2535
December1st to 15thNight
9%32331225%7%58%
2535
16th to endNight
8%424323446%54%
2704

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
29%25%20%27%13%
1711
16th to endDay
27%28%16%29%15%
1848
February1st to 15thDay
24%26%18%27%19%
1751
16th to endDay
28%2418%29%17%
1580
March1st to 15thDay
31%26%16%28%13%
1879
16th to endDay
29%37%20%24%13%
2112
April1st to 15thDay
26%410%16%22%19%
2072
16th to endDay
29%36%17%26%17%
2202
May1st to 15thDay
34%48%19%19%14%
2331
16th to endDay
33%5%10%20%22%7%
2434
June1st to 15thDay
22%412%24%27%7%
2340
16th to endDay
26%5%12%26%21%7%
2340
July1st to 15thDay
28%7%17%28%16%2
2201
16th to endDay
20%5%16%35%19%1
2311
August1st to 15thDay
22%5%15%28%24%4
2198
16th to endDay
32%8%14%24%18%2
2292
September1st to 15thDay
34%6%12%20%20%6%
2004
16th to endDay
31%48%20%23%10%
1980
October1st to 15thDay
23%411%25%23%11%
1980
16th to endDay
17%2419%32%22%
1953
November1st to 15thDay
22%48%24%25%13%
1730
16th to endDay
23%25%19%29%20%
1755
December1st to 15thDay
31%26%17%29%13%
1755
16th to endDay
31%36%21%27%9%
1872
January1st to 15thNight
26%1419%28%18%
2472
16th to endNight
22%3417%29%22%
2385
February1st to 15thNight
28%25%14%25%22%
2112
16th to endNight
25%35%18%26%21%
1894
March1st to 15thNight
30%36%16%23%18%
2079
16th to endNight
25%39%22%24%14%
2112
April1st to 15thNight
24%410%20%18%21%
1873
16th to endNight
22%410%18%25%16%
1755
May1st to 15thNight
28%5%10%18%21%15%
1620
16th to endNight
21%8%15%24%21%8%
1685
June1st to 15thNight
17%6%14%28%26%7%
1620
16th to endNight
19%5%12%31%23%8%
1620
July1st to 15thNight
20%6%13%34%20%4
1530
16th to endNight
13%5%16%34%26%3
1594
August1st to 15thNight
16%413%30%29%5%
1735
16th to endNight
22%6%14%28%22%5%
1910
September1st to 15thNight
28%5%11%25%20%8%
1955
16th to endNight
29%410%21%21%12%
1980
October1st to 15thNight
20%412%24%24%13%
1980
16th to endNight
17%25%17%31%24%
2256
November1st to 15thNight
22%38%24%23%18%
2455
16th to endNight
24%3415%31%21%
2535
December1st to 15thNight
27%27%20%24%16%
2535
16th to endNight
30%45%18%25%14%
2704

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
13%13%30%34%7%1
123
16th to endDay
9%11%42%28%8%
96
February1st to 15thDay
6%7%40%34%10%1
90
16th to endDay
11%355%22%6%1
81
March1st to 15thDay
13%10%42%27%6%
90
16th to endDay
5%15%35%30%12%1
96
April1st to 15thDay
6%16%49%23%3
191
16th to endDay
10%15%41%24%7%1
312
May1st to 15thDay
13%9%40%28%5%2
468
16th to endDay
15%5%32%31%13%
517
June1st to 15thDay
6%120%47%20%3
495
16th to endDay
6%16%33%35%7%
495
July1st to 15thDay
7%6%38%40%5%
475
16th to endDay
4330%45%16%
515
August1st to 15thDay
5%126%48%16%
367
16th to endDay
7%10%35%34%11%
332
September1st to 15thDay
4127%47%18%
159
16th to endDay
19%7%22%37%13%
135
October1st to 15thDay
3115%42%29%6%
135
16th to endDay
8%327%31%22%6%
144
November1st to 15thDay
18%425%37%10%3
135
16th to endDay
13%14%32%22%12%5%
135
December1st to 15thDay
19%6%35%29%5%2
135
16th to endDay
14%11%43%25%5%
144
January1st to 15thNight
11%9%35%34%8%
956
16th to endNight
9%9%39%32%7%
849
February1st to 15thNight
11%9%41%30%7%
704
16th to endNight
11%11%48%24%3
632
March1st to 15thNight
12%9%46%25%5%
639
16th to endNight
9%10%47%28%4
576
April1st to 15thNight
7%12%53%22%3
539
16th to endNight
7%8%53%24%6%
540
May1st to 15thNight
7%7%49%27%6%
540
16th to endNight
6%243%34%12%
563
June1st to 15thNight
4134%46%11%
540
16th to endNight
423%49%21%1
540
July1st to 15thNight
5%11%50%30%1
510
16th to endNight
3451%37%1
564
August1st to 15thNight
2243%48%2
539
16th to endNight
48%41%41%4
573
September1st to 15thNight
10%8%44%34%2
540
16th to endNight
11%16%40%29%1
537
October1st to 15thNight
7%226%43%19%1
540
16th to endNight
6%5%28%39%17%2
720
November1st to 15thNight
8%433%35%16%1
935
16th to endNight
9%8%35%32%13%
975
December1st to 15thNight
12%7%34%37%7%
975
16th to endNight
11%9%37%32%8%
1040
Page generated at 2018-01-12 21:01:34. Version ac04

Copyright 2018 A. Danko


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