Glendo State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Glendo State Park clear sky chart from 2005-11-05 to 2017-12-20.

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
46%
16470
24%
48055
15%
16429
54%
16429
36%
27632

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%
899
23%
2506
13%
895
47%
895
32%
1502
January16th to endNight
35%
885
26%
2613
13%
885
48%
885
34%
1497
February1st to 15thNight
40%
699
19%
2281
13%
699
48%
699
29%
1335
February16th to endNight
35%
632
22%
1894
10%
632
46%
632
31%
1128
March1st to 15thNight
42%
720
23%
2133
11%
720
52%
720
35%
1231
March16th to endNight
39%
670
21%
2014
12%
670
48%
670
30%
1231
April1st to 15thNight
39%
539
18%
1798
13%
539
48%
539
25%
1102
April16th to endNight
35%
540
16%
1788
11%
540
43%
540
22%
1143
May1st to 15thNight
45%
540
20%
1497
13%
540
50%
540
31%
939
May16th to endNight
48%
562
17%
1498
9%
561
53%
561
31%
976
June1st to 15thNight
46%
540
17%
1440
8%
540
52%
540
40%
848
June16th to endNight
57%
540
24%
1440
14%
540
62%
540
58%
724
July1st to 15thNight
62%
510
20%
1360
13%
510
66%
510
47%
758
July16th to endNight
68%
564
25%
1416
18%
531
71%
531
51%
759
August1st to 15thNight
66%
539
25%
1568
19%
536
71%
536
46%
812
August16th to endNight
67%
573
30%
1910
29%
573
73%
573
42%
948
September1st to 15thNight
57%
540
27%
1800
24%
540
66%
540
38%
939
September16th to endNight
59%
537
35%
1933
31%
537
68%
537
43%
911
October1st to 15thNight
48%
714
25%
2154
17%
714
54%
714
34%
1277
October16th to endNight
47%
843
32%
2379
16%
843
58%
843
42%
1320
November1st to 15thNight
46%
950
27%
2470
15%
950
52%
950
41%
1451
November16th to endNight
45%
975
30%
2678
15%
975
56%
975
43%
1480
December1st to 15thNight
33%
975
20%
2730
10%
975
43%
975
32%
1645
December16th to endNight
38%
984
22%
2755
11%
984
48%
984
32%
1676

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
6%5%2342446%8%51%
48795
Night
5%5%2442445%7%53%
48221
Cloud CoverDay
5%5%244245%6%8%51%
48805
Night
5%5%2442445%7%53%
48226
TransparencyDay
29%6%14%25%17%6%
48478
Night
29%6%14%26%17%5%
48055
SeeingDay
9%8%29%29%18%4
6270
Night
7%8%33%37%12%
16477

By Month

Percentage Cloud Cover NE (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
25%24425%5%6%10%51%
1432
16th to endDay
35%25%32446%7%54%
1620
February1st to 15thDay
29%34425%5%6%9%45%
1581
16th to endDay
48%35%5%35%5%5%7%46%
1580
March1st to 15thDay
37%2442246%7%54%
1817
16th to endDay
7%5%25%6%2445%8%47%
2208
April1st to 15thDay
9%6%25%42346%9%46%
2150
16th to endDay
12%8%25%5%36%5%47%37%
2172
May1st to 15thDay
11%7%35%5%25%45%7%42%
2452
16th to endDay
11%5%245%46%6%7%8%37%
2616
June1st to 15thDay
8%422425%6%6%10%47%
2520
16th to endDay
22122347%9%62%
2520
July1st to 15thDay
4213335%47%8%54%
2520
16th to endDay
4313335%5%7%8%53%
2656
August1st to 15thDay
42135%35%6%7%9%51%
2381
16th to endDay
431231445%8%59%
2292
September1st to 15thDay
8%42323447%57%
2160
16th to endDay
5%312222347%64%
2026
October1st to 15thDay
9%5%13414347%53%
1803
16th to endDay
4413323448%58%
1833
November1st to 15thDay
44233245%5%7%56%
1718
16th to endDay
33234235%5%8%56%
1610
December1st to 15thDay
36%344345%5%8%49%
1560
16th to endDay
47%35%31445%8%50%
1568
January1st to 15thNight
3426%43446%7%51%
2506
16th to endNight
35%25%43445%6%54%
2613
February1st to 15thNight
36%245%35%46%8%48%
2277
16th to endNight
38%35%4245%5%6%49%
1894
March1st to 15thNight
45%24435%45%7%52%
2120
16th to endNight
7%6%36%5%2445%7%46%
2014
April1st to 15thNight
9%5%35%5%3445%7%45%
1798
16th to endNight
14%6%35%5%25%336%43%
1788
May1st to 15thNight
10%5%14434447%48%
1497
16th to endNight
10%414426%5%6%8%46%
1497
June1st to 15thNight
7%312235%45%9%52%
1440
16th to endNight
22221335%7%67%
1440
July1st to 15thNight
5%2123145%6%8%57%
1440
16th to endNight
411232445%8%61%
1512
August1st to 15thNight
22143235%7%10%56%
1576
16th to endNight
331342445%6%59%
1910
September1st to 15thNight
7%423422336%58%
1800
16th to endNight
6%312323245%64%
1933
October1st to 15thNight
11%5%24323346%52%
2154
16th to endNight
5%5%1332335%6%58%
2379
November1st to 15thNight
45%144235%5%7%55%
2470
16th to endNight
25%1332436%8%56%
2678
December1st to 15thNight
46%35%43435%8%50%
2730
16th to endNight
37%2443445%8%49%
2755

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
15%24435%5%5%10%51%
1432
16th to endDay
35%2431445%8%53%
1620
February1st to 15thDay
210%34425%5%6%9%45%
1581
16th to endDay
47%35%5%26%5%5%7%46%
1580
March1st to 15thDay
37%2442345%7%54%
1827
16th to endDay
6%5%246%2446%8%47%
2208
April1st to 15thDay
8%6%35%42345%8%46%
2150
16th to endDay
12%8%25%5%36%5%5%7%37%
2172
May1st to 15thDay
11%6%35%5%25%46%7%41%
2452
16th to endDay
10%5%25%5%36%6%7%8%37%
2616
June1st to 15thDay
8%413425%6%6%10%47%
2520
16th to endDay
221122347%9%62%
2520
July1st to 15thDay
4213325%5%7%8%53%
2520
16th to endDay
4213325%6%7%9%53%
2656
August1st to 15thDay
4213435%6%8%9%51%
2381
16th to endDay
43232345%8%59%
2292
September1st to 15thDay
8%41232345%7%57%
2160
16th to endDay
5%312213347%64%
2026
October1st to 15thDay
9%5%23324346%53%
1803
16th to endDay
3413323448%58%
1833
November1st to 15thDay
342333446%7%55%
1718
16th to endDay
33243235%5%8%55%
1610
December1st to 15thDay
37%344245%6%8%48%
1560
16th to endDay
47%3442445%8%50%
1568
January1st to 15thNight
2425%5%35%5%6%7%50%
2506
16th to endNight
2435%434447%53%
2613
February1st to 15thNight
36%25%436%5%5%8%48%
2270
16th to endNight
38%35%4345%5%7%48%
1894
March1st to 15thNight
45%24425%46%7%52%
2133
16th to endNight
7%6%36%42445%8%46%
2014
April1st to 15thNight
9%5%35%5%3446%7%45%
1798
16th to endNight
14%5%35%5%24446%42%
1788
May1st to 15thNight
10%5%24425%45%7%48%
1496
16th to endNight
10%314425%5%5%9%45%
1497
June1st to 15thNight
7%413225%47%9%52%
1440
16th to endNight
22221335%8%66%
1440
July1st to 15thNight
5%21232446%9%57%
1440
16th to endNight
411233346%8%61%
1512
August1st to 15thNight
22143245%6%10%56%
1576
16th to endNight
332342445%6%59%
1910
September1st to 15thNight
6%434422346%57%
1800
16th to endNight
6%313323236%64%
1933
October1st to 15thNight
10%5%24323346%52%
2154
16th to endNight
5%5%2332335%6%57%
2379
November1st to 15thNight
44245%235%5%7%55%
2470
16th to endNight
25%2342436%8%56%
2678
December1st to 15thNight
36%35%43445%9%49%
2730
16th to endNight
37%2443446%9%48%
2755

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%8%21%30%11%1
1433
16th to endDay
27%5%19%30%15%2
1620
February1st to 15thDay
33%8%19%26%10%2
1581
16th to endDay
35%6%16%25%11%4
1580
March1st to 15thDay
28%5%15%30%16%3
1827
16th to endDay
34%7%13%28%13%2
2208
April1st to 15thDay
34%6%15%26%13%3
2150
16th to endDay
44%6%13%20%13%1
2172
May1st to 15thDay
40%7%13%24%13%1
2452
16th to endDay
39%9%15%21%11%2
2620
June1st to 15thDay
29%7%15%24%17%5%
2520
16th to endDay
16%5%12%24%27%13%
2520
July1st to 15thDay
25%5%12%21%20%14%
2371
16th to endDay
23%7%10%22%21%15%
2489
August1st to 15thDay
23%8%13%23%18%13%
2365
16th to endDay
21%49%21%27%16%
2292
September1st to 15thDay
25%49%19%25%15%
2160
16th to endDay
20%48%31%28%6%
2026
October1st to 15thDay
31%5%12%27%18%5%
1803
16th to endDay
23%5%14%30%18%7%
1833
November1st to 15thDay
25%6%14%25%22%6%
1718
16th to endDay
23%5%16%30%21%2
1610
December1st to 15thDay
30%7%21%26%12%1
1560
16th to endDay
31%5%20%28%12%1
1568
January1st to 15thNight
29%8%16%29%14%2
2506
16th to endNight
29%5%16%29%15%3
2613
February1st to 15thNight
31%8%19%27%10%2
2281
16th to endNight
33%5%16%25%15%3
1894
March1st to 15thNight
29%6%13%27%17%5%
2133
16th to endNight
35%6%15%26%14%2
2014
April1st to 15thNight
36%8%13%23%13%4
1798
16th to endNight
42%6%12%23%14%1
1788
May1st to 15thNight
34%7%14%25%16%1
1497
16th to endNight
34%9%17%22%13%2
1498
June1st to 15thNight
26%7%20%26%15%3
1440
16th to endNight
15%5%14%28%25%10%
1440
July1st to 15thNight
23%5%12%26%19%11%
1360
16th to endNight
19%6%12%24%22%14%
1416
August1st to 15thNight
20%6%15%29%17%10%
1568
16th to endNight
24%48%20%26%15%
1910
September1st to 15thNight
27%47%24%24%12%
1800
16th to endNight
22%36%31%25%9%
1933
October1st to 15thNight
32%5%12%21%22%4
2154
16th to endNight
25%5%12%28%19%8%
2379
November1st to 15thNight
27%5%13%24%22%6%
2470
16th to endNight
23%5%13%32%19%4
2678
December1st to 15thNight
31%6%18%28%12%2
2730
16th to endNight
32%7%19%28%11%1
2755

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%5%25%31%15%13%
90
16th to endDay
46%40%32%13%3
96
February1st to 15thDay
8%16%44%23%6%
90
16th to endDay
9%19%33%25%9%1
81
March1st to 15thDay
11%14%29%29%12%
117
16th to endDay
12%15%40%22%6%
288
April1st to 15thDay
15%17%40%17%7%1
269
16th to endDay
21%15%28%22%9%2
282
May1st to 15thDay
14%11%29%25%15%4
468
16th to endDay
15%9%25%29%16%3
517
June1st to 15thDay
8%7%30%29%17%6%
495
16th to endDay
3431%35%23%1
495
July1st to 15thDay
4319%36%30%6%
475
16th to endDay
4124%37%27%4
515
August1st to 15thDay
6%325%33%27%4
372
16th to endDay
6%5%22%31%23%10%
332
September1st to 15thDay
6%5%31%26%24%4
315
16th to endDay
8%5%29%26%20%8%
181
October1st to 15thDay
10%8%23%34%15%6%
135
16th to endDay
7%12%30%31%13%4
144
November1st to 15thDay
37%30%35%13%9%
135
16th to endDay
12%15%37%31%3
135
December1st to 15thDay
5%17%37%24%13%1
135
16th to endDay
6%9%31%36%14%1
108
January1st to 15thNight
416%36%29%12%1
900
16th to endNight
6%13%40%30%8%
885
February1st to 15thNight
6%9%37%37%9%
704
16th to endNight
7%9%41%31%8%
632
March1st to 15thNight
7%8%37%36%9%
720
16th to endNight
10%8%35%37%7%
670
April1st to 15thNight
11%10%35%36%6%
539
16th to endNight
15%9%32%31%10%
540
May1st to 15thNight
13%8%29%35%12%1
540
16th to endNight
12%5%29%34%16%1
563
June1st to 15thNight
9%6%35%35%13%
540
16th to endNight
3233%47%12%
540
July1st to 15thNight
7%124%43%21%1
510
16th to endNight
4121%50%21%
564
August1st to 15thNight
4123%49%20%
539
16th to endNight
3220%46%26%
573
September1st to 15thNight
8%322%40%23%1
540
16th to endNight
7%326%40%19%2
537
October1st to 15thNight
13%5%28%34%14%1
714
16th to endNight
7%6%33%36%14%1
843
November1st to 15thNight
6%9%32%36%14%
950
16th to endNight
5%10%36%39%7%1
975
December1st to 15thNight
6%12%41%30%7%
975
16th to endNight
8%12%35%35%8%
984
Page generated at 2017-12-21 05:04:44. Version ac04

Copyright 2017 A. Danko


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