Devils River State Natural Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Devils River State Natural Area clear sky chart from 2005-11-05 to 2018-10-08.

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%
16760
29%
51156
19%
16717
61%
16717
41%
27281

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
44%
924
30%
2475
15%
923
53%
923
40%
1457
January16th to endNight
44%
832
33%
2496
18%
832
57%
832
37%
1382
February1st to 15thNight
40%
764
31%
2287
15%
758
54%
758
39%
1217
February16th to endNight
28%
684
30%
2050
9%
684
46%
684
38%
1103
March1st to 15thNight
31%
730
30%
2290
12%
730
48%
730
38%
1214
March16th to endNight
28%
624
27%
2288
15%
624
45%
624
34%
1186
April1st to 15thNight
25%
584
31%
1971
12%
584
48%
584
38%
1010
April16th to endNight
27%
579
32%
1929
13%
579
53%
579
40%
983
May1st to 15thNight
31%
584
25%
1816
14%
584
47%
584
35%
1015
May16th to endNight
40%
609
25%
1828
15%
609
56%
609
38%
1044
June1st to 15thNight
58%
585
25%
1755
20%
585
69%
585
59%
809
June16th to endNight
64%
585
23%
1755
22%
585
70%
585
44%
937
July1st to 15thNight
74%
555
23%
1665
25%
555
76%
555
41%
917
July16th to endNight
81%
612
30%
1848
34%
579
87%
579
52%
872
August1st to 15thNight
87%
575
30%
1908
36%
572
89%
572
53%
851
August16th to endNight
79%
621
26%
2070
29%
621
81%
621
40%
1074
September1st to 15thNight
78%
585
22%
2090
27%
585
78%
585
33%
1163
September16th to endNight
64%
582
23%
2145
23%
582
68%
582
30%
1203
October1st to 15thNight
63%
564
34%
2068
30%
564
71%
564
42%
975
October16th to endNight
61%
642
39%
2178
28%
642
70%
642
51%
976
November1st to 15thNight
55%
950
30%
2470
14%
950
62%
950
48%
1376
November16th to endNight
53%
975
37%
2535
18%
975
61%
975
51%
1351
December1st to 15thNight
49%
975
31%
2535
17%
975
55%
975
39%
1531
December16th to endNight
40%
1040
30%
2704
14%
1040
50%
1040
38%
1635

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
9%423323446%53%
51960
Night
7%313323347%58%
51368
Cloud CoverDay
9%423323446%53%
51958
Night
7%313323347%58%
51368
TransparencyDay
30%5%10%20%20%11%
51668
Night
25%5%11%21%21%14%
51163
SeeingDay
10%322%37%21%3
6691
Night
8%431%40%12%
16767

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
11%5%24323225%55%
1804
16th to endDay
9%422323335%59%
2080
February1st to 15thDay
8%5%23314335%58%
1900
16th to endDay
8%423323346%58%
1710
March1st to 15thDay
13%6%24213335%53%
1999
16th to endDay
12%423222346%56%
2288
April1st to 15thDay
9%423323346%56%
2304
16th to endDay
9%424223346%55%
2306
May1st to 15thDay
12%41442345%8%48%
2461
16th to endDay
12%5%2432435%6%48%
2638
June1st to 15thDay
5%312323449%59%
2535
16th to endDay
8%3235%35%46%8%48%
2535
July1st to 15thDay
8%4245%25%5%6%6%48%
2535
16th to endDay
6%2123245%6%8%56%
2552
August1st to 15thDay
321342445%9%57%
2294
16th to endDay
6%324435%5%6%8%49%
2484
September1st to 15thDay
12%5%25%5%45%6%6%7%38%
2199
16th to endDay
11%5%245%345%46%45%
2145
October1st to 15thDay
9%41332345%5%55%
2061
16th to endDay
7%31331223466%
2030
November1st to 15thDay
11%423313446%55%
1718
16th to endDay
9%413213225%62%
1755
December1st to 15thDay
16%5%13323336%50%
1755
16th to endDay
13%7%24312345%51%
1872
January1st to 15thNight
10%5%24223235%56%
2475
16th to endNight
11%422322336%56%
2496
February1st to 15thNight
9%5%13213246%58%
2282
16th to endNight
9%412323346%57%
2050
March1st to 15thNight
10%412313346%57%
2290
16th to endNight
8%313313347%58%
2288
April1st to 15thNight
7%21332335%8%58%
1971
16th to endNight
6%323223236%62%
1929
May1st to 15thNight
8%42432345%6%55%
1816
16th to endNight
8%31332335%8%54%
1827
June1st to 15thNight
21111345%12%63%
1755
16th to endNight
42133245%6%10%56%
1755
July1st to 15thNight
5%21342445%9%56%
1755
16th to endNight
311221345%8%64%
1965
August1st to 15thNight
111221345%9%66%
1919
16th to endNight
5%21332336%11%55%
2070
September1st to 15thNight
5%31443446%8%51%
2090
16th to endNight
8%4145%2436%9%48%
2145
October1st to 15thNight
6%213312346%63%
2068
16th to endNight
5%3221233470%
2178
November1st to 15thNight
8%31231333464%
2470
16th to endNight
7%212212335%66%
2535
December1st to 15thNight
13%5%1322235%8%52%
2535
16th to endNight
10%6%23313336%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
11%6%24323235%55%
1804
16th to endDay
10%322323345%59%
2080
February1st to 15thDay
7%6%23223335%58%
1900
16th to endDay
8%5%23322346%58%
1710
March1st to 15thDay
13%5%23312336%53%
1999
16th to endDay
12%5%12312346%56%
2286
April1st to 15thDay
9%324323336%56%
2304
16th to endDay
9%5%23314346%56%
2306
May1st to 15thDay
11%5%2441345%7%49%
2461
16th to endDay
12%5%24324447%47%
2638
June1st to 15thDay
5%31232345%9%59%
2535
16th to endDay
8%323435%5%6%8%48%
2535
July1st to 15thDay
8%4245%25%5%5%6%48%
2535
16th to endDay
6%2133345%7%7%55%
2552
August1st to 15thDay
32134245%5%8%57%
2294
16th to endDay
6%313435%5%7%8%48%
2484
September1st to 15thDay
11%5%35%5%35%6%6%7%38%
2199
16th to endDay
11%5%25%435%446%45%
2145
October1st to 15thDay
9%424323445%55%
2061
16th to endDay
7%31321233466%
2030
November1st to 15thDay
10%424223347%55%
1718
16th to endDay
9%5%13322225%61%
1755
December1st to 15thDay
15%6%23323335%50%
1755
16th to endDay
13%7%24312346%51%
1872
January1st to 15thNight
10%5%24323235%56%
2475
16th to endNight
11%412312337%56%
2496
February1st to 15thNight
8%5%13312246%58%
2282
16th to endNight
9%413314346%58%
2050
March1st to 15thNight
10%413222346%57%
2290
16th to endNight
8%313323346%58%
2288
April1st to 15thNight
7%31332335%7%58%
1971
16th to endNight
6%413313336%63%
1929
May1st to 15thNight
8%42432245%7%54%
1816
16th to endNight
8%32332335%9%53%
1827
June1st to 15thNight
21121345%12%63%
1755
16th to endNight
42123245%5%11%55%
1755
July1st to 15thNight
421432446%10%55%
1755
16th to endNight
311221335%9%63%
1965
August1st to 15thNight
111221345%9%66%
1919
16th to endNight
5%21332346%11%54%
2070
September1st to 15thNight
5%41443446%9%51%
2090
16th to endNight
8%4245%2346%8%48%
2145
October1st to 15thNight
7%213213336%63%
2068
16th to endNight
431221333470%
2178
November1st to 15thNight
7%31331234464%
2470
16th to endNight
7%312212335%66%
2535
December1st to 15thNight
12%5%2222335%8%51%
2535
16th to endNight
10%6%23312345%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
33%2419%25%13%
1805
16th to endDay
27%38%14%29%16%
2080
February1st to 15thDay
29%37%17%21%20%
1901
16th to endDay
28%47%14%27%17%
1710
March1st to 15thDay
33%47%17%18%19%
1999
16th to endDay
30%48%18%19%18%
2288
April1st to 15thDay
29%47%16%21%19%
2304
16th to endDay
29%48%20%17%19%
2306
May1st to 15thDay
32%5%11%18%20%10%
2461
16th to endDay
36%5%9%22%19%6%
2642
June1st to 15thDay
22%5%13%27%22%7%
2535
16th to endDay
31%7%14%22%19%4
2535
July1st to 15thDay
33%6%15%26%14%2
2396
16th to endDay
20%8%21%30%18%
2406
August1st to 15thDay
21%7%16%32%19%1
2281
16th to endDay
29%9%17%25%16%2
2484
September1st to 15thDay
41%8%13%18%13%3
2199
16th to endDay
37%5%11%17%19%7%
2145
October1st to 15thDay
30%6%11%22%18%9%
2061
16th to endDay
22%36%12%31%23%
2030
November1st to 15thDay
31%39%23%18%13%
1718
16th to endDay
28%26%14%24%23%
1755
December1st to 15thDay
38%26%16%24%11%
1755
16th to endDay
35%27%17%24%11%
1872
January1st to 15thNight
31%35%16%24%18%
2475
16th to endNight
29%35%14%24%21%
2496
February1st to 15thNight
27%37%15%21%24%
2292
16th to endNight
27%37%15%25%19%
2050
March1st to 15thNight
27%310%16%20%21%
2290
16th to endNight
27%5%11%17%20%17%
2288
April1st to 15thNight
24%5%11%18%17%22%
1971
16th to endNight
24%410%23%19%17%
1929
May1st to 15thNight
29%5%11%20%19%12%
1817
16th to endNight
27%7%13%23%22%6%
1829
June1st to 15thNight
12%5%18%28%26%7%
1755
16th to endNight
22%7%15%27%20%6%
1755
July1st to 15thNight
23%8%16%28%20%3
1665
16th to endNight
14%7%19%34%21%2
1848
August1st to 15thNight
14%6%18%33%25%2
1908
16th to endNight
22%8%19%28%17%3
2070
September1st to 15thNight
27%8%16%23%17%5%
2090
16th to endNight
32%6%15%22%14%8%
2145
October1st to 15thNight
22%414%28%19%11%
2068
16th to endNight
17%37%14%30%25%
2178
November1st to 15thNight
23%38%23%25%14%
2470
16th to endNight
21%38%17%22%27%
2535
December1st to 15thNight
31%38%17%21%15%
2535
16th to endNight
32%36%16%24%16%
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
14%6%27%38%13%
135
16th to endDay
10%10%33%30%14%
144
February1st to 15thDay
14%5%30%29%17%1
135
16th to endDay
12%10%44%28%5%
120
March1st to 15thDay
20%5%38%25%8%1
135
16th to endDay
9%436%38%9%1
144
April1st to 15thDay
7%9%49%30%2
303
16th to endDay
8%9%43%29%8%
318
May1st to 15thDay
16%6%39%32%5%
478
16th to endDay
14%5%32%37%9%
597
June1st to 15thDay
5%121%55%13%1
570
16th to endDay
7%117%42%27%3
570
July1st to 15thDay
9%19%45%29%4
550
16th to endDay
45%41%41%6%
473
August1st to 15thDay
45%42%36%10%
359
16th to endDay
5%17%40%38%7%
396
September1st to 15thDay
12%428%44%10%
234
16th to endDay
17%17%32%31%10%
180
October1st to 15thDay
7%11%43%35%2
157
16th to endDay
13%418%37%22%4
144
November1st to 15thDay
22%5%21%25%20%3
135
16th to endDay
17%8%26%22%15%8%
135
December1st to 15thDay
21%6%24%31%11%4
135
16th to endDay
20%8%28%30%9%2
144
January1st to 15thNight
12%6%33%39%8%
928
16th to endNight
13%6%33%36%9%
832
February1st to 15thNight
13%8%36%33%7%
764
16th to endNight
12%8%48%27%2
684
March1st to 15thNight
13%6%46%28%4
730
16th to endNight
8%10%50%27%2
624
April1st to 15thNight
7%8%58%22%2
584
16th to endNight
5%8%57%24%3
579
May1st to 15thNight
8%8%49%30%3
585
16th to endNight
7%5%44%34%7%
611
June1st to 15thNight
235%55%5%
585
16th to endNight
228%52%14%
585
July1st to 15thNight
5%13%56%20%2
555
16th to endNight
39%63%22%
612
August1st to 15thNight
2459%31%2
575
16th to endNight
5%7%56%27%2
621
September1st to 15thNight
5%6%49%33%3
585
16th to endNight
9%115%43%27%1
582
October1st to 15thNight
7%125%48%17%
564
16th to endNight
5%326%45%17%1
642
November1st to 15thNight
8%428%39%17%1
950
16th to endNight
9%5%29%38%16%1
975
December1st to 15thNight
15%5%26%41%10%
975
16th to endNight
13%7%33%37%6%
1040
Page generated at 2018-10-09 09:39:17. Version ac04

Copyright 2018 A. Danko


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