Eureka Springs Ranch
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Eureka Springs Ranch clear sky chart from 2005-11-05 to 2017-09-24.

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
72%
15522
34%
46973
30%
15483
77%
15483
49%
23195

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
71%
718
30%
2327
32%
716
75%
716
47%
1122
January16th to endNight
66%
768
34%
2496
35%
768
72%
768
39%
1306
February1st to 15thNight
69%
700
34%
2246
33%
699
77%
699
48%
1088
February16th to endNight
61%
632
38%
1814
32%
632
69%
632
46%
967
March1st to 15thNight
62%
720
38%
1980
28%
720
72%
720
52%
1007
March16th to endNight
70%
768
38%
2112
27%
768
79%
768
61%
1010
April1st to 15thNight
64%
656
34%
1915
24%
656
74%
656
52%
933
April16th to endNight
68%
540
44%
1800
38%
540
80%
540
67%
676
May1st to 15thNight
70%
539
38%
1630
30%
539
79%
539
64%
682
May16th to endNight
72%
561
39%
1684
32%
561
77%
561
68%
700
June1st to 15thNight
81%
540
34%
1620
30%
540
82%
540
67%
691
June16th to endNight
84%
540
29%
1620
25%
540
84%
540
57%
749
July1st to 15thNight
78%
510
17%
1530
15%
510
79%
510
34%
900
July16th to endNight
75%
564
15%
1593
14%
531
75%
531
24%
1067
August1st to 15thNight
82%
539
22%
1611
20%
536
81%
536
36%
941
August16th to endNight
81%
573
29%
1869
31%
573
81%
573
36%
1034
September1st to 15thNight
76%
690
27%
1950
25%
690
76%
690
38%
1154
September16th to endNight
79%
692
42%
1914
31%
692
84%
692
65%
886
October1st to 15thNight
77%
660
39%
1939
31%
660
82%
660
60%
888
October16th to endNight
82%
704
43%
2112
36%
704
87%
704
66%
906
November1st to 15thNight
77%
700
42%
2100
35%
700
82%
700
64%
919
November16th to endNight
71%
720
38%
2275
35%
720
76%
720
50%
1098
December1st to 15thNight
69%
720
35%
2340
36%
720
73%
720
46%
1128
December16th to endNight
63%
768
33%
2496
32%
768
69%
768
37%
1343

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
4213323446%63%
47952
Night
3213323346%64%
47170
TransparencyDay
20%47%12%28%26%
47647
Night
19%46%13%28%27%
46976
SeeingDay
5%12%26%33%18%4
5371
Night
4313%37%34%7%
15531

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
5%313313346%62%
1611
16th to endDay
7%423212245%61%
1728
February1st to 15thDay
4313223345%64%
1613
16th to endDay
5%413424336%60%
1658
March1st to 15thDay
432331335%5%63%
1980
16th to endDay
221222323471%
2112
April1st to 15thDay
1112313446%69%
2033
16th to endDay
21121223477%
2160
May1st to 15thDay
211213335%74%
2317
16th to endDay
21111222378%
2429
June1st to 15thDay
1211112235%77%
2340
16th to endDay
2112223445%70%
2340
July1st to 15thDay
5%3134346%8%10%46%
2340
16th to endDay
7%315%6%47%8%9%10%34%
2467
August1st to 15thDay
6%4245%37%6%7%9%42%
2340
16th to endDay
4314435%6%7%9%48%
2333
September1st to 15thDay
6%4145%36%5%6%7%49%
2007
16th to endDay
312213335%69%
1904
October1st to 15thDay
2112213345%71%
1690
16th to endDay
1112212335%75%
1760
November1st to 15thDay
211213246%73%
1759
16th to endDay
331331333468%
1683
December1st to 15thDay
5%413222347%61%
1620
16th to endDay
6%413314447%57%
1728
January1st to 15thNight
5%413223245%63%
2327
16th to endNight
7%423424335%59%
2496
February1st to 15thNight
3323313336%65%
2236
16th to endNight
4413424445%60%
1814
March1st to 15thNight
4312213345%66%
1980
16th to endNight
311213345%71%
2112
April1st to 15thNight
321231334468%
1915
16th to endNight
1112222382%
1800
May1st to 15thNight
111112335%76%
1630
16th to endNight
2111123480%
1684
June1st to 15thNight
1211111225%77%
1620
16th to endNight
211323445%70%
1620
July1st to 15thNight
3314436%7%7%9%46%
1620
16th to endNight
4226%7%47%6%9%13%33%
1701
August1st to 15thNight
32145%35%7%6%10%49%
1620
16th to endNight
32145%26%5%7%10%49%
1869
September1st to 15thNight
5%4244346%5%8%51%
1950
16th to endNight
2112211235%74%
1914
October1st to 15thNight
2112312235%73%
1939
16th to endNight
11211123478%
2112
November1st to 15thNight
1111212245%73%
2100
16th to endNight
431231434467%
2275
December1st to 15thNight
6%33213346%62%
2340
16th to endNight
6%5%2443334456%
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
23%35%12%36%19%
1612
16th to endDay
25%2416%28%22%
1728
February1st to 15thDay
21%27%14%27%27%
1613
16th to endDay
25%3415%30%21%
1658
March1st to 15thDay
22%247%36%26%
1980
16th to endDay
17%2410%39%26%
2112
April1st to 15thDay
15%249%39%27%
2033
16th to endDay
12%239%30%42%
2160
May1st to 15thDay
12%25%9%32%38%
2317
16th to endDay
12%248%30%41%
2432
June1st to 15thDay
11%235%24%52%
2340
16th to endDay
15%35%8%20%46%
2340
July1st to 15thDay
27%10%15%15%14%16%
2201
16th to endDay
37%14%19%18%8%1
2312
August1st to 15thDay
34%10%11%15%18%8%
2325
16th to endDay
30%9%12%17%21%9%
2333
September1st to 15thDay
31%7%10%16%18%14%
2007
16th to endDay
17%35%12%36%26%
1904
October1st to 15thDay
16%4412%31%30%
1690
16th to endDay
12%3411%33%35%
1760
November1st to 15thDay
12%1313%38%29%
1759
16th to endDay
19%2311%32%30%
1683
December1st to 15thDay
22%26%20%30%17%
1620
16th to endDay
25%48%19%31%10%
1728
January1st to 15thNight
22%36%13%31%23%
2327
16th to endNight
27%3415%28%20%
2496
February1st to 15thNight
20%35%14%28%27%
2247
16th to endNight
23%45%13%31%21%
1814
March1st to 15thNight
19%3410%32%30%
1980
16th to endNight
14%25%13%39%25%
2112
April1st to 15thNight
18%2411%38%24%
1915
16th to endNight
9%1210%34%41%
1800
May1st to 15thNight
11%15%9%34%37%
1631
16th to endNight
9%239%29%45%
1685
June1st to 15thNight
11%12421%57%
1620
16th to endNight
16%25%6%19%48%
1620
July1st to 15thNight
28%9%15%15%13%16%
1530
16th to endNight
35%14%19%21%5%2
1593
August1st to 15thNight
26%10%15%17%18%11%
1611
16th to endNight
25%9%14%18%20%11%
1869
September1st to 15thNight
28%7%10%19%19%14%
1950
16th to endNight
14%1415%35%28%
1914
October1st to 15thNight
14%2417%27%32%
1939
16th to endNight
11%2414%28%39%
2112
November1st to 15thNight
13%2313%37%29%
2100
16th to endNight
20%3412%25%33%
2275
December1st to 15thNight
21%35%16%32%19%
2340
16th to endNight
28%47%17%30%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
15%11%24%38%8%1
90
16th to endDay
7%9%22%34%19%6%
96
February1st to 15thDay
410%22%36%22%2
128
16th to endDay
7%28%31%23%7%
238
March1st to 15thDay
6%24%29%25%12%2
270
16th to endDay
327%33%20%11%3
288
April1st to 15thDay
6%24%39%17%7%3
269
16th to endDay
5%29%36%20%5%2
270
May1st to 15thDay
422%42%19%8%2
288
16th to endDay
214%39%32%8%1
330
June1st to 15thDay
39%36%33%12%3
315
16th to endDay
3130%39%20%4
315
July1st to 15thDay
3117%50%24%2
305
16th to endDay
6%114%37%25%14%
327
August1st to 15thDay
5%111%39%33%8%
315
16th to endDay
4111%40%33%8%
332
September1st to 15thDay
9%116%45%22%4
315
16th to endDay
5%8%25%36%18%4
288
October1st to 15thDay
26%23%39%23%5%
130
16th to endDay
7%115%39%34%2
96
November1st to 15thDay
412%22%34%22%4
90
16th to endDay
318%31%28%17%
90
December1st to 15thDay
27%18%38%30%2
90
16th to endDay
11%20%18%35%12%1
96
January1st to 15thNight
6%215%46%25%4
720
16th to endNight
7%415%41%25%5%
768
February1st to 15thNight
36%14%42%28%4
704
16th to endNight
5%424%44%19%2
632
March1st to 15thNight
47%21%35%27%3
720
16th to endNight
35%17%37%30%5%
768
April1st to 15thNight
37%18%43%24%2
656
16th to endNight
17%20%43%22%5%
540
May1st to 15thNight
25%17%42%27%4
540
16th to endNight
1320%38%31%3
563
June1st to 15thNight
2210%42%38%3
540
16th to endNight
17%35%49%5%
540
July1st to 15thNight
45%30%51%7%
510
16th to endNight
41319%56%14%
564
August1st to 15thNight
2317%57%18%
539
16th to endNight
3419%55%17%
573
September1st to 15thNight
6%8%26%47%10%
690
16th to endNight
2111%35%37%11%
692
October1st to 15thNight
2113%41%33%6%
660
16th to endNight
119%39%34%11%
704
November1st to 15thNight
2116%37%33%9%
700
16th to endNight
6%315%38%30%6%
720
December1st to 15thNight
8%314%39%29%4
720
16th to endNight
6%5%15%44%20%6%
768
Page generated at 2017-09-25 06:02:29. Version ac04

Copyright 2017 A. Danko


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