Lake Whitney State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Whitney State Park clear sky chart from 2005-11-05 to 2017-08-12.

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
51%
15413
29%
46538
20%
15368
60%
15368
38%
25639

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
39%
896
28%
2327
13%
895
47%
895
37%
1410
January16th to endNight
36%
960
31%
2496
13%
960
47%
960
37%
1492
February1st to 15thNight
33%
713
28%
2114
12%
706
45%
706
32%
1239
February16th to endNight
25%
629
31%
1891
10%
629
43%
629
34%
1058
March1st to 15thNight
34%
540
27%
1980
15%
540
48%
540
26%
1146
March16th to endNight
34%
576
26%
2112
16%
576
49%
576
31%
1112
April1st to 15thNight
32%
539
25%
1977
12%
539
51%
539
31%
1048
April16th to endNight
34%
540
27%
1725
14%
540
51%
540
34%
979
May1st to 15thNight
37%
539
23%
1620
15%
539
50%
539
33%
948
May16th to endNight
48%
562
24%
1684
18%
561
60%
561
37%
951
June1st to 15thNight
68%
540
24%
1620
24%
540
74%
540
51%
801
June16th to endNight
73%
540
25%
1620
28%
540
76%
540
43%
868
July1st to 15thNight
81%
510
26%
1530
29%
510
84%
510
49%
775
July16th to endNight
85%
564
29%
1594
34%
531
88%
531
53%
779
August1st to 15thNight
90%
527
36%
1575
43%
524
90%
524
62%
708
August16th to endNight
80%
525
25%
1773
30%
525
80%
525
37%
937
September1st to 15thNight
71%
495
23%
1815
28%
495
73%
495
33%
973
September16th to endNight
74%
492
31%
1815
31%
492
78%
492
39%
900
October1st to 15thNight
68%
544
35%
1864
30%
544
74%
544
44%
904
October16th to endNight
54%
704
37%
2112
23%
704
64%
704
46%
1077
November1st to 15thNight
52%
718
31%
2118
18%
718
61%
718
42%
1146
November16th to endNight
45%
900
32%
2340
16%
900
53%
900
38%
1392
December1st to 15thNight
41%
900
31%
2340
15%
900
49%
900
37%
1419
December16th to endNight
38%
960
25%
2496
11%
960
47%
960
32%
1577

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
23%313323346%45%
47423
Night
22%312212236%49%
46741
Cloud CoverDay
10%42442445%7%51%
47421
Night
9%313323347%56%
46741
TransparencyDay
32%5%10%21%21%8%
47121
Night
28%410%21%22%12%
46546
SeeingDay
10%418%30%27%9%
5386
Night
11%5%26%35%17%1
15419

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
29%41221212345%
1611
16th to endDay
25%41321223448%
1728
February1st to 15thDay
25%5%2431222345%
1750
16th to endDay
27%413211235%46%
1581
March1st to 15thDay
33%5%1332222439%
1980
16th to endDay
24%41332223446%
2112
April1st to 15thDay
24%414312345%42%
1971
16th to endDay
25%423322335%42%
2232
May1st to 15thDay
27%5%24322245%38%
2331
16th to endDay
24%4245%235%5%8%32%
2430
June1st to 15thDay
19%2333345%7%45%
2340
16th to endDay
20%21342345%6%46%
2340
July1st to 15thDay
20%2332345%7%45%
2340
16th to endDay
21%1222435%8%45%
2466
August1st to 15thDay
11%1122345%7%58%
2289
16th to endDay
16%3134346%6%9%40%
2072
September1st to 15thDay
18%3135%345%5%7%40%
1815
16th to endDay
15%313423347%48%
1815
October1st to 15thDay
18%213213336%51%
1755
16th to endDay
16%31221123462%
1760
November1st to 15thDay
23%314322235%48%
1737
16th to endDay
28%41321222348%
1620
December1st to 15thDay
33%6%1322122438%
1620
16th to endDay
28%6%1421233440%
1728
January1st to 15thNight
28%41231123346%
2327
16th to endNight
26%21221123450%
2496
February1st to 15thNight
28%42321112447%
2111
16th to endNight
25%31221222450%
1891
March1st to 15thNight
30%41322233440%
1980
16th to endNight
22%412212235%50%
2112
April1st to 15thNight
22%21332325%6%47%
1977
16th to endNight
25%413212345%45%
1725
May1st to 15thNight
23%313213247%45%
1619
16th to endNight
22%312323448%44%
1683
June1st to 15thNight
18%212212247%52%
1620
16th to endNight
18%12222337%53%
1620
July1st to 15thNight
19%11213347%53%
1620
16th to endNight
19%1212449%51%
1702
August1st to 15thNight
11%1111239%64%
1585
16th to endNight
14%2134345%5%8%46%
1773
September1st to 15thNight
18%31322336%7%46%
1815
16th to endNight
15%313313347%52%
1815
October1st to 15thNight
16%22212246%58%
1864
16th to endNight
17%2221212461%
2112
November1st to 15thNight
21%31321233453%
2118
16th to endNight
28%41231222346%
2340
December1st to 15thNight
29%5%13211235%42%
2340
16th to endNight
27%5%13322335%40%
2496

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
14%5%1321323355%
1611
16th to endDay
13%41321334455%
1728
February1st to 15thDay
11%6%26%31323454%
1750
16th to endDay
15%5%14212236%53%
1581
March1st to 15thDay
16%6%13423335%47%
1980
16th to endDay
13%5%24423345%50%
2110
April1st to 15thDay
9%425%42345%7%49%
1971
16th to endDay
10%5%24424446%48%
2232
May1st to 15thDay
12%6%35%335%35%7%44%
2331
16th to endDay
9%5%25%5%35%5%8%9%38%
2430
June1st to 15thDay
4213435%5%5%8%55%
2340
16th to endDay
6%324435%46%8%49%
2340
July1st to 15thDay
6%3234346%6%8%50%
2340
16th to endDay
5%223336%5%6%9%51%
2466
August1st to 15thDay
21233446%10%60%
2289
16th to endDay
6%414435%6%7%11%44%
2072
September1st to 15thDay
10%3236%45%6%6%7%43%
1815
16th to endDay
6%41442445%8%53%
1815
October1st to 15thDay
9%313323446%56%
1755
16th to endDay
8%3321213468%
1760
November1st to 15thDay
10%314422336%56%
1737
16th to endDay
13%31431222459%
1620
December1st to 15thDay
17%5%23322235%50%
1620
16th to endDay
14%7%24313445%48%
1728
January1st to 15thNight
13%423312235%56%
2327
16th to endNight
13%32331324457%
2496
February1st to 15thNight
13%43432123456%
2111
16th to endNight
13%41331223458%
1891
March1st to 15thNight
13%5%24324346%48%
1980
16th to endNight
8%5%23313347%55%
2112
April1st to 15thNight
7%32441445%8%53%
1977
16th to endNight
10%42322345%5%54%
1725
May1st to 15thNight
9%425%32446%9%48%
1619
16th to endNight
7%31331447%9%51%
1683
June1st to 15thNight
221332325%9%64%
1620
16th to endNight
431332445%9%58%
1620
July1st to 15thNight
421231347%10%58%
1620
16th to endNight
21232446%11%60%
1702
August1st to 15thNight
11112123410%69%
1585
16th to endNight
4313435%47%10%51%
1773
September1st to 15thNight
10%42342335%9%50%
1815
16th to endNight
7%31332345%8%57%
1815
October1st to 15thNight
7%212212446%62%
1864
16th to endNight
9%31221223466%
2112
November1st to 15thNight
7%313413335%62%
2118
16th to endNight
12%31331333458%
2340
December1st to 15thNight
13%5%23212336%53%
2340
16th to endNight
13%6%13323345%50%
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
34%35%18%26%11%
1612
16th to endDay
31%36%18%26%13%
1728
February1st to 15thDay
34%4417%24%13%
1751
16th to endDay
34%25%19%22%15%
1581
March1st to 15thDay
40%37%15%23%9%
1980
16th to endDay
37%48%19%22%8%
2112
April1st to 15thDay
34%49%20%17%12%
1971
16th to endDay
37%5%7%17%23%8%
2232
May1st to 15thDay
40%5%8%18%18%8%
2331
16th to endDay
39%8%12%18%17%2
2434
June1st to 15thDay
26%6%13%27%21%5%
2340
16th to endDay
31%6%14%23%19%4
2340
July1st to 15thDay
29%7%17%28%15%2
2201
16th to endDay
26%8%19%27%17%1
2311
August1st to 15thDay
17%6%16%33%22%3
2275
16th to endDay
31%8%18%25%14%2
2072
September1st to 15thDay
35%6%13%21%15%6%
1815
16th to endDay
28%5%9%22%23%10%
1815
October1st to 15thDay
27%411%21%19%16%
1755
16th to endDay
21%25%17%33%19%
1760
November1st to 15thDay
30%39%25%20%11%
1737
16th to endDay
30%2417%26%18%
1620
December1st to 15thDay
38%27%22%21%7%
1620
16th to endDay
37%47%19%23%7%
1728
January1st to 15thNight
32%35%17%24%16%
2327
16th to endNight
31%35%16%25%17%
2496
February1st to 15thNight
33%36%13%25%17%
2121
16th to endNight
31%37%18%23%16%
1891
March1st to 15thNight
36%5%9%13%22%13%
1980
16th to endNight
29%411%21%26%7%
2112
April1st to 15thNight
29%5%9%19%20%15%
1977
16th to endNight
31%5%11%18%23%10%
1725
May1st to 15thNight
31%5%12%19%19%10%
1620
16th to endNight
28%6%17%24%19%4
1685
June1st to 15thNight
18%5%13%30%25%6%
1620
16th to endNight
22%7%12%27%23%5%
1620
July1st to 15thNight
19%5%16%36%17%2
1530
16th to endNight
14%7%21%35%18%2
1594
August1st to 15thNight
12%415%35%27%5%
1575
16th to endNight
25%7%18%31%14%3
1773
September1st to 15thNight
30%5%14%25%16%8%
1815
16th to endNight
24%5%9%23%22%13%
1815
October1st to 15thNight
21%411%24%19%17%
1864
16th to endNight
23%2317%27%25%
2112
November1st to 15thNight
26%48%22%24%14%
2118
16th to endNight
31%25%13%27%18%
2340
December1st to 15thNight
33%38%21%20%11%
2340
16th to endNight
36%47%17%22%12%
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%13%25%32%10%2
90
16th to endDay
13%10%42%21%10%1
96
February1st to 15thDay
6%10%37%40%5%
90
16th to endDay
18%9%48%17%6%
81
March1st to 15thDay
23%10%36%20%7%2
90
16th to endDay
11%7%41%23%13%2
96
April1st to 15thDay
14%17%26%24%16%
90
16th to endDay
13%14%33%27%10%
342
May1st to 15thDay
14%9%34%28%10%1
468
16th to endDay
13%432%27%17%3
517
June1st to 15thDay
4113%45%27%8%
495
16th to endDay
7%111%37%31%10%
495
July1st to 15thDay
5%16%35%40%10%
475
16th to endDay
5%424%44%20%
515
August1st to 15thDay
4227%45%18%
474
16th to endDay
13%431%37%12%
240
September1st to 15thDay
217%43%36%
90
16th to endDay
5%112%51%30%
90
October1st to 15thDay
28%35%42%11%
90
16th to endDay
16%415%25%33%5%
96
November1st to 15thDay
21%5%23%32%14%3
90
16th to endDay
24%16%22%21%12%3
90
December1st to 15thDay
26%5%25%21%15%5%
90
16th to endDay
16%11%39%26%6%
96
January1st to 15thNight
16%9%30%33%9%
900
16th to endNight
15%9%35%32%6%
960
February1st to 15thNight
16%11%34%31%4
713
16th to endNight
17%10%44%24%2
629
March1st to 15thNight
17%7%37%32%5%
540
16th to endNight
10%11%42%30%6%
576
April1st to 15thNight
8%9%47%30%4
539
16th to endNight
12%7%43%27%8%
540
May1st to 15thNight
10%8%37%33%8%1
540
16th to endNight
9%334%33%16%2
563
June1st to 15thNight
420%48%24%1
540
16th to endNight
3114%47%28%3
540
July1st to 15thNight
5%6%48%35%2
510
16th to endNight
35%42%44%4
564
August1st to 15thNight
2241%46%6%
527
16th to endNight
8%436%44%6%
525
September1st to 15thNight
12%17%35%38%5%
495
16th to endNight
7%28%35%40%5%
492
October1st to 15thNight
9%216%41%26%3
544
16th to endNight
11%5%25%35%19%2
704
November1st to 15thNight
10%429%34%19%
718
16th to endNight
15%8%28%33%13%1
900
December1st to 15thNight
18%6%30%34%9%
900
16th to endNight
18%8%31%32%8%
960
Page generated at 2017-08-13 13:16:19. Version ac04

Copyright 2017 A. Danko


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