Little River Canyon National Preserve
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Little River Canyon National Preserve clear sky chart from 2005-11-05 to 2017-09-23.

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
49%
15373
24%
47023
17%
15330
57%
15330
29%
28574

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
28%
720
23%
2327
10%
716
44%
716
21%
1480
January16th to endNight
27%
768
26%
2388
12%
768
42%
768
23%
1537
February1st to 15thNight
29%
704
25%
2112
10%
701
43%
701
27%
1290
February16th to endNight
27%
631
24%
1893
10%
631
40%
631
25%
1211
March1st to 15thNight
32%
720
21%
2117
13%
720
40%
720
24%
1357
March16th to endNight
41%
768
22%
2112
14%
768
47%
768
30%
1330
April1st to 15thNight
46%
543
25%
1801
19%
543
57%
543
34%
986
April16th to endNight
51%
540
28%
1758
21%
540
62%
540
34%
982
May1st to 15thNight
54%
540
22%
1620
14%
540
60%
540
32%
975
May16th to endNight
67%
561
22%
1682
17%
561
71%
561
35%
999
June1st to 15thNight
73%
540
19%
1620
16%
540
75%
540
37%
930
June16th to endNight
79%
540
18%
1620
16%
540
80%
540
39%
920
July1st to 15thNight
75%
510
16%
1530
14%
510
76%
510
34%
925
July16th to endNight
71%
564
19%
1595
17%
531
74%
531
31%
991
August1st to 15thNight
74%
539
21%
1723
23%
536
75%
536
32%
1013
August16th to endNight
66%
573
20%
1910
22%
573
68%
573
25%
1221
September1st to 15thNight
63%
651
19%
1911
17%
651
65%
651
28%
1225
September16th to endNight
63%
689
27%
1903
21%
689
67%
689
35%
1173
October1st to 15thNight
56%
660
35%
1815
28%
660
62%
660
40%
1061
October16th to endNight
50%
704
33%
2134
26%
704
61%
704
36%
1190
November1st to 15thNight
49%
700
30%
2276
24%
700
60%
700
35%
1238
November16th to endNight
39%
720
27%
2340
18%
720
52%
720
28%
1367
December1st to 15thNight
34%
720
23%
2340
15%
720
45%
720
23%
1476
December16th to endNight
30%
768
20%
2496
14%
768
39%
768
19%
1697

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
14%5%25%5%35%5%5%7%40%
47878
Night
13%42442445%7%46%
47222
TransparencyDay
41%411%20%17%4
47579
Night
37%410%21%20%5%
47025
SeeingDay
16%5%17%22%23%15%
5267
Night
15%7%21%29%22%4
15375

By Month

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
21%6%24323445%40%
1611
16th to endDay
18%42343435%5%44%
1833
February1st to 15thDay
18%7%23434347%40%
1750
16th to endDay
19%6%36%42424441%
1580
March1st to 15thDay
18%6%35%436%345%38%
1842
16th to endDay
16%5%35%5%2446%6%38%
2117
April1st to 15thDay
14%5%245%345%47%43%
2151
16th to endDay
11%425%5%4445%6%45%
2202
May1st to 15thDay
13%5%25%43435%6%44%
2331
16th to endDay
12%424435%5%6%8%40%
2431
June1st to 15thDay
8%5%26%6%46%6%6%9%35%
2340
16th to endDay
6%425%446%6%8%10%41%
2340
July1st to 15thDay
10%5%35%6%48%7%7%10%31%
2340
16th to endDay
7%5%26%7%6%7%8%8%10%29%
2465
August1st to 15thDay
7%425%7%47%7%8%11%32%
2224
16th to endDay
13%6%26%7%35%7%7%8%30%
2292
September1st to 15thDay
14%6%25%5%35%5%7%8%35%
2035
16th to endDay
14%5%25%42445%6%45%
1894
October1st to 15thDay
12%5%24323335%53%
1815
16th to endDay
12%42441222357%
1735
November1st to 15thDay
13%423323335%53%
1582
16th to endDay
19%313323345%47%
1620
December1st to 15thDay
21%7%25%334446%38%
1620
16th to endDay
27%6%35%5%2333434%
1728
January1st to 15thNight
19%5%24425%346%42%
2327
16th to endNight
17%6%25%433345%42%
2388
February1st to 15thNight
16%6%24323247%46%
2103
16th to endNight
17%425%434346%42%
1893
March1st to 15thNight
15%5%25%42445%6%42%
2117
16th to endNight
13%5%24423446%47%
2112
April1st to 15thNight
12%413224448%50%
1801
16th to endNight
10%3235%1435%6%53%
1758
May1st to 15thNight
11%32443446%8%46%
1619
16th to endNight
7%323425%6%6%9%47%
1682
June1st to 15thNight
6%4144345%6%10%47%
1620
16th to endNight
43135%26%5%6%13%47%
1620
July1st to 15thNight
7%4245%36%48%10%41%
1620
16th to endNight
5%325%6%36%6%7%11%40%
1703
August1st to 15thNight
6%425%425%5%6%11%43%
1734
16th to endNight
13%5%136%35%5%6%9%38%
1910
September1st to 15thNight
9%425%7%345%7%8%40%
1911
16th to endNight
11%414434437%49%
1903
October1st to 15thNight
11%414312345%56%
1815
16th to endNight
11%42332423457%
2134
November1st to 15thNight
12%323223345%55%
2276
16th to endNight
16%5%2331344449%
2340
December1st to 15thNight
17%6%25%424346%41%
2340
16th to endNight
24%6%25%423345%35%
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
46%36%18%20%4
1612
16th to endDay
41%27%22%20%5%
1833
February1st to 15thDay
44%28%23%18%3
1752
16th to endDay
46%26%20%20%4
1580
March1st to 15thDay
48%37%17%19%3
1842
16th to endDay
44%412%22%14%2
2118
April1st to 15thDay
39%311%21%18%5%
2151
16th to endDay
38%210%23%20%4
2202
May1st to 15thDay
40%312%23%16%3
2331
16th to endDay
38%415%25%12%2
2435
June1st to 15thDay
40%5%17%23%12%
2340
16th to endDay
34%6%14%24%16%3
2340
July1st to 15thDay
41%7%18%19%10%2
2201
16th to endDay
42%8%19%19%9%1
2310
August1st to 15thDay
39%8%17%21%11%1
2211
16th to endDay
47%5%15%17%10%2
2292
September1st to 15thDay
42%6%15%17%12%4
2035
16th to endDay
39%410%20%19%5%
1894
October1st to 15thDay
34%47%17%27%9%
1815
16th to endDay
33%1419%30%9%
1735
November1st to 15thDay
33%2418%31%9%
1582
16th to endDay
38%26%19%25%6%
1620
December1st to 15thDay
47%26%20%16%5%
1620
16th to endDay
53%27%18%13%3
1728
January1st to 15thNight
43%37%19%21%4
2327
16th to endNight
44%25%20%20%5%
2388
February1st to 15thNight
40%17%22%21%6%
2112
16th to endNight
43%25%23%21%4
1893
March1st to 15thNight
41%48%19%18%7%
2117
16th to endNight
38%210%25%19%2
2112
April1st to 15thNight
31%212%24%20%7%
1801
16th to endNight
31%38%26%22%6%
1758
May1st to 15thNight
34%5%13%20%23%2
1620
16th to endNight
31%6%17%25%14%3
1684
June1st to 15thNight
30%419%28%15%1
1620
16th to endNight
27%6%20%22%18%4
1620
July1st to 15thNight
32%7%20%23%11%4
1530
16th to endNight
33%8%19%22%13%2
1595
August1st to 15thNight
32%6%19%22%15%2
1723
16th to endNight
39%7%16%18%14%2
1910
September1st to 15thNight
38%6%17%17%15%4
1911
16th to endNight
35%49%23%21%6%
1903
October1st to 15thNight
30%37%23%23%11%
1815
16th to endNight
32%1316%32%13%
2134
November1st to 15thNight
31%25%19%28%13%
2276
16th to endNight
37%25%19%26%8%
2340
December1st to 15thNight
44%28%19%19%5%
2340
16th to endNight
50%38%18%16%4
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
23%18%32%20%32
90
16th to endDay
17%20%50%6%5%
96
February1st to 15thDay
20%23%44%12%
90
16th to endDay
30%7%43%17%1
81
March1st to 15thDay
19%15%36%20%5%2
132
16th to endDay
21%8%28%25%14%1
288
April1st to 15thDay
16%10%27%22%20%1
270
16th to endDay
15%5%21%28%22%6%
270
May1st to 15thDay
14%7%23%23%18%11%
288
16th to endDay
18%213%21%24%19%
331
June1st to 15thDay
13%8%19%29%28%
315
16th to endDay
9%18%22%26%30%
315
July1st to 15thDay
11%17%19%32%27%
305
16th to endDay
10%415%30%37%
326
August1st to 15thDay
13%15%23%34%20%
313
16th to endDay
17%1327%28%22%
332
September1st to 15thDay
15%310%17%31%21%
315
16th to endDay
16%37%28%32%12%
283
October1st to 15thDay
16%118%31%24%7%
255
16th to endDay
16%418%27%26%6%
206
November1st to 15thDay
25%11%21%27%12%2
90
16th to endDay
15%13%35%22%12%1
90
December1st to 15thDay
26%14%34%13%11%
90
16th to endDay
31%14%26%22%5%
96
January1st to 15thNight
23%14%29%25%7%
720
16th to endNight
22%12%33%28%3
768
February1st to 15thNight
20%13%32%31%2
704
16th to endNight
19%13%36%26%3
631
March1st to 15thNight
18%13%33%29%5%
720
16th to endNight
16%11%24%32%14%1
768
April1st to 15thNight
13%8%27%31%16%1
543
16th to endNight
12%424%35%20%1
540
May1st to 15thNight
11%422%32%24%4
540
16th to endNight
9%111%33%36%7%
563
June1st to 15thNight
7%18%31%40%10%
540
16th to endNight
416%27%43%15%
540
July1st to 15thNight
6%5%22%48%15%
510
16th to endNight
7%16%20%45%18%
564
August1st to 15thNight
8%1325%48%12%
539
16th to endNight
15%26%23%43%9%
573
September1st to 15thNight
11%27%29%37%11%
651
16th to endNight
13%113%30%37%3
689
October1st to 15thNight
14%219%32%25%4
660
16th to endNight
13%7%22%31%21%4
704
November1st to 15thNight
13%7%24%31%20%2
700
16th to endNight
19%11%27%28%13%
720
December1st to 15thNight
20%11%27%29%10%
720
16th to endNight
27%9%27%27%7%
768
Page generated at 2017-09-24 08:15:52. Version ac04

Copyright 2017 A. Danko


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