Great Plains State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Great Plains State Park clear sky chart from 2005-11-05 to 2018-01-20.

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
48%
16252
31%
48495
19%
16209
59%
16209
42%
25508

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
43%
974
32%
2522
14%
970
55%
970
47%
1368
January16th to endNight
44%
979
38%
2555
17%
979
57%
979
51%
1358
February1st to 15thNight
38%
703
29%
2112
14%
700
51%
700
38%
1160
February16th to endNight
30%
632
33%
1894
12%
632
48%
632
38%
1004
March1st to 15thNight
34%
618
29%
2058
14%
618
49%
618
33%
1104
March16th to endNight
31%
576
25%
2112
15%
576
46%
576
32%
1069
April1st to 15thNight
27%
539
26%
1903
12%
539
47%
539
34%
951
April16th to endNight
30%
540
29%
1680
14%
540
49%
540
35%
922
May1st to 15thNight
33%
539
27%
1620
14%
539
51%
539
36%
899
May16th to endNight
48%
561
28%
1684
21%
561
61%
561
42%
902
June1st to 15thNight
51%
540
24%
1620
15%
540
63%
540
49%
802
June16th to endNight
60%
540
26%
1620
22%
540
67%
540
48%
818
July1st to 15thNight
75%
510
21%
1530
22%
510
78%
510
45%
817
July16th to endNight
85%
564
32%
1594
36%
531
87%
531
55%
758
August1st to 15thNight
82%
539
31%
1610
35%
536
83%
536
47%
823
August16th to endNight
78%
573
27%
1905
31%
573
81%
573
43%
954
September1st to 15thNight
62%
540
24%
1968
24%
540
68%
540
32%
1066
September16th to endNight
60%
537
34%
1980
28%
537
71%
537
36%
998
October1st to 15thNight
52%
552
34%
1992
28%
552
60%
552
38%
984
October16th to endNight
52%
768
39%
2304
21%
768
64%
768
54%
1074
November1st to 15thNight
46%
938
32%
2458
12%
938
58%
938
52%
1290
November16th to endNight
43%
975
38%
2535
16%
975
56%
975
49%
1369
December1st to 15thNight
43%
975
34%
2535
15%
975
55%
975
46%
1401
December16th to endNight
38%
1040
33%
2704
14%
1040
50%
1040
38%
1617

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%313323446%57%
49032
Night
6%313323347%59%
48691
Cloud CoverDay
7%313323446%57%
49030
Night
6%313323347%59%
48691
TransparencyDay
27%410%24%25%8%
48730
Night
24%39%23%26%11%
48496
SeeingDay
8%5%24%32%23%4
6052
Night
8%6%32%36%14%
16257

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
7%423223346%60%
1746
16th to endDay
6%423223337%60%
1782
February1st to 15thDay
7%6%2332233460%
1750
16th to endDay
8%6%2332333458%
1580
March1st to 15thDay
11%5%23413446%51%
1902
16th to endDay
10%5%23322346%53%
2112
April1st to 15thDay
9%5%13323346%57%
2042
16th to endDay
10%413313447%54%
2279
May1st to 15thDay
10%5%34424445%51%
2331
16th to endDay
9%32443446%7%49%
2430
June1st to 15thDay
5%2134245%5%8%55%
2340
16th to endDay
5%11232446%8%58%
2340
July1st to 15thDay
6%3244345%6%8%50%
2340
16th to endDay
3233245%5%9%60%
2466
August1st to 15thDay
42133245%5%8%57%
2340
16th to endDay
42134345%7%9%53%
2295
September1st to 15thDay
9%224324447%52%
1990
16th to endDay
9%32332235%6%57%
1980
October1st to 15thDay
11%21322234461%
1956
16th to endDay
5%21232323369%
1920
November1st to 15thDay
6%312212336%66%
1729
16th to endDay
8%22112235%66%
1755
December1st to 15thDay
7%5%23422446%56%
1755
16th to endDay
10%5%24423335%52%
1872
January1st to 15thNight
6%313213337%62%
2522
16th to endNight
6%313213345%65%
2555
February1st to 15thNight
10%42221333460%
2102
16th to endNight
9%413312237%58%
1894
March1st to 15thNight
8%424224446%55%
2058
16th to endNight
9%422223446%57%
2112
April1st to 15thNight
8%312223448%56%
1903
16th to endNight
11%31432335%6%54%
1680
May1st to 15thNight
9%313322347%57%
1619
16th to endNight
5%22342336%8%58%
1683
June1st to 15thNight
321332247%10%59%
1620
16th to endNight
422321436%10%59%
1620
July1st to 15thNight
23133245%7%12%53%
1620
16th to endNight
21131446%9%62%
1702
August1st to 15thNight
32133245%7%9%56%
1620
16th to endNight
221342447%9%55%
1905
September1st to 15thNight
9%423424447%51%
1968
16th to endNight
6%314424447%56%
1980
October1st to 15thNight
8%313323435%60%
1992
16th to endNight
421211223472%
2304
November1st to 15thNight
4212223346%66%
2458
16th to endNight
8%313212225%66%
2535
December1st to 15thNight
8%313212345%61%
2535
16th to endNight
9%6%24313346%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
7%413223345%60%
1746
16th to endDay
6%413222347%60%
1782
February1st to 15thDay
7%6%2431233460%
1750
16th to endDay
8%6%2332323459%
1580
March1st to 15thDay
11%5%14323446%51%
1902
16th to endDay
10%5%34323246%54%
2110
April1st to 15thDay
8%413323346%57%
2042
16th to endDay
10%313323446%55%
2279
May1st to 15thDay
11%434424445%51%
2331
16th to endDay
8%32443445%7%50%
2430
June1st to 15thDay
5%3134245%5%8%55%
2340
16th to endDay
5%11232446%7%59%
2340
July1st to 15thDay
7%3235%245%6%8%50%
2340
16th to endDay
421232445%9%60%
2466
August1st to 15thDay
42134245%5%8%57%
2340
16th to endDay
42134245%7%9%54%
2295
September1st to 15thDay
9%414424447%51%
1990
16th to endDay
9%323323346%57%
1980
October1st to 15thDay
10%213313335%61%
1956
16th to endDay
421232323369%
1920
November1st to 15thDay
5%313212335%67%
1729
16th to endDay
8%212212335%66%
1755
December1st to 15thDay
7%5%24322445%56%
1755
16th to endDay
11%5%25%323335%52%
1872
January1st to 15thNight
6%313223347%61%
2522
16th to endNight
6%322313235%65%
2555
February1st to 15thNight
10%413213235%60%
2102
16th to endNight
9%413312347%58%
1894
March1st to 15thNight
8%324324446%55%
2058
16th to endNight
9%423312446%57%
2112
April1st to 15thNight
8%313314448%56%
1903
16th to endNight
10%414323345%55%
1680
May1st to 15thNight
9%312324347%57%
1619
16th to endNight
5%22332345%8%58%
1683
June1st to 15thNight
321322246%11%59%
1620
16th to endNight
422231335%10%60%
1620
July1st to 15thNight
23133245%6%12%54%
1620
16th to endNight
22232346%9%62%
1702
August1st to 15thNight
3224245%7%9%56%
1620
16th to endNight
31144235%6%10%55%
1905
September1st to 15thNight
8%42441345%8%51%
1968
16th to endNight
6%324423446%57%
1980
October1st to 15thNight
9%313323345%60%
1992
16th to endNight
421221224471%
2304
November1st to 15thNight
4212212346%66%
2458
16th to endNight
7%213212225%65%
2535
December1st to 15thNight
8%213213345%61%
2535
16th to endNight
8%7%23323345%55%
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
25%39%26%27%7%
1747
16th to endDay
24%27%23%34%7%
1782
February1st to 15thDay
28%35%25%27%8%
1751
16th to endDay
30%16%22%26%11%
1580
March1st to 15thDay
33%38%22%21%11%
1902
16th to endDay
31%411%25%18%8%
2112
April1st to 15thDay
28%311%21%22%12%
2042
16th to endDay
29%49%22%25%7%
2279
May1st to 15thDay
34%49%18%23%9%
2331
16th to endDay
32%5%11%23%20%5%
2434
June1st to 15thDay
25%6%13%25%22%7%
2340
16th to endDay
22%6%12%25%23%9%
2340
July1st to 15thDay
29%6%12%25%21%4
2201
16th to endDay
19%411%31%27%4
2311
August1st to 15thDay
22%6%14%25%22%8%
2326
16th to endDay
24%7%12%25%22%7%
2295
September1st to 15thDay
31%5%9%22%21%8%
1990
16th to endDay
28%47%23%27%8%
1980
October1st to 15thDay
25%410%23%26%10%
1956
16th to endDay
20%35%23%32%14%
1920
November1st to 15thDay
19%28%27%27%13%
1729
16th to endDay
21%15%24%33%12%
1755
December1st to 15thDay
29%310%24%25%6%
1755
16th to endDay
34%38%22%25%6%
1872
January1st to 15thNight
23%29%22%31%10%
2522
16th to endNight
22%17%20%34%13%
2555
February1st to 15thNight
28%36%22%27%11%
2112
16th to endNight
27%26%23%25%14%
1894
March1st to 15thNight
29%47%20%22%15%
2058
16th to endNight
27%312%24%21%9%
2112
April1st to 15thNight
26%311%21%23%13%
1903
16th to endNight
29%48%23%22%11%
1680
May1st to 15thNight
27%5%10%18%25%12%
1620
16th to endNight
23%6%15%23%22%8%
1685
June1st to 15thNight
19%415%31%21%6%
1620
16th to endNight
20%412%27%24%10%
1620
July1st to 15thNight
22%6%12%26%24%6%
1530
16th to endNight
16%411%32%27%7%
1594
August1st to 15thNight
21%5%12%23%25%11%
1610
16th to endNight
23%413%24%24%8%
1905
September1st to 15thNight
31%5%9%19%22%10%
1968
16th to endNight
27%48%22%26%11%
1980
October1st to 15thNight
26%48%24%21%15%
1992
16th to endNight
17%25%20%35%18%
2304
November1st to 15thNight
19%38%23%29%15%
2458
16th to endNight
22%2422%31%15%
2535
December1st to 15thNight
23%39%24%27%11%
2535
16th to endNight
31%28%20%27%9%
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
11%11%32%31%11%1
135
16th to endDay
313%43%28%9%1
109
February1st to 15thDay
5%14%43%30%6%
90
16th to endDay
311%41%33%9%
81
March1st to 15thDay
11%18%44%23%2
90
16th to endDay
7%15%37%23%14%1
96
April1st to 15thDay
14%18%34%27%5%
161
16th to endDay
14%14%36%25%7%1
389
May1st to 15thDay
9%9%40%29%9%1
468
16th to endDay
12%6%31%28%16%2
517
June1st to 15thDay
7%129%36%21%3
495
16th to endDay
5%116%41%28%6%
495
July1st to 15thDay
6%112%40%32%7%
475
16th to endDay
2433%49%10%
515
August1st to 15thDay
6%438%45%5%
493
16th to endDay
5%12%38%32%8%
335
September1st to 15thDay
37%34%37%16%
145
16th to endDay
14%114%31%25%12%
135
October1st to 15thDay
6%5%28%30%25%3
135
16th to endDay
6%7%24%38%20%2
144
November1st to 15thDay
17%238%21%13%5%
135
16th to endDay
15%10%38%22%11%1
135
December1st to 15thDay
8%6%42%31%8%
135
16th to endDay
18%17%36%24%3
144
January1st to 15thNight
8%9%35%36%9%
975
16th to endNight
7%7%37%38%9%
979
February1st to 15thNight
11%9%36%33%8%
704
16th to endNight
12%10%43%28%4
632
March1st to 15thNight
11%10%40%30%6%
618
16th to endNight
10%13%41%29%5%
576
April1st to 15thNight
9%13%47%26%2
539
16th to endNight
12%9%46%26%5%
540
May1st to 15thNight
9%9%46%24%9%
540
16th to endNight
6%5%35%37%14%1
563
June1st to 15thNight
4336%39%14%
540
16th to endNight
4227%47%17%1
540
July1st to 15thNight
413%50%29%
510
16th to endNight
25%51%36%3
564
August1st to 15thNight
46%46%40%1
539
16th to endNight
311%45%36%2
573
September1st to 15thNight
10%118%37%29%2
540
16th to endNight
7%122%42%23%2
537
October1st to 15thNight
10%330%37%17%1
552
16th to endNight
6%6%33%38%15%
768
November1st to 15thNight
7%7%35%36%12%1
938
16th to endNight
9%8%36%33%12%
975
December1st to 15thNight
10%10%32%35%10%
975
16th to endNight
13%10%34%33%7%
1040
Page generated at 2018-01-21 11:19:28. Version ac04

Copyright 2018 A. Danko


Great Plains State Park Clear Sky Chart |Charts Home