Caprock Canyons Trailway
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Caprock Canyons Trailway clear sky chart from 2005-11-05 to 2017-09-17.

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
54%
15683
32%
46959
20%
15637
65%
15637
45%
24045

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
49%
899
33%
2327
17%
895
60%
895
51%
1229
January16th to endNight
49%
855
39%
2391
20%
855
63%
855
51%
1215
February1st to 15thNight
43%
704
30%
2112
15%
700
56%
700
39%
1128
February16th to endNight
40%
632
35%
1894
15%
632
58%
632
42%
970
March1st to 15thNight
36%
684
30%
2124
15%
684
50%
684
38%
1127
March16th to endNight
39%
576
29%
2102
19%
576
55%
576
37%
995
April1st to 15thNight
33%
539
30%
1798
15%
539
54%
539
37%
911
April16th to endNight
35%
540
32%
1764
16%
540
57%
540
42%
862
May1st to 15thNight
40%
540
30%
1620
17%
540
58%
540
42%
858
May16th to endNight
49%
563
28%
1684
19%
561
64%
561
44%
885
June1st to 15thNight
53%
540
22%
1620
16%
540
62%
540
46%
840
June16th to endNight
67%
540
26%
1620
23%
540
73%
540
52%
786
July1st to 15thNight
77%
510
23%
1530
23%
510
80%
510
46%
795
July16th to endNight
86%
564
32%
1594
35%
531
87%
531
57%
751
August1st to 15thNight
84%
539
29%
1736
36%
536
84%
536
44%
866
August16th to endNight
79%
573
26%
1910
31%
573
80%
573
40%
1004
September1st to 15thNight
70%
540
24%
1905
26%
540
73%
540
33%
1059
September16th to endNight
67%
498
33%
1837
33%
498
73%
498
41%
873
October1st to 15thNight
56%
495
37%
1815
31%
495
67%
495
42%
856
October16th to endNight
59%
717
40%
2125
22%
717
70%
717
58%
962
November1st to 15thNight
57%
875
37%
2275
16%
875
67%
875
59%
1118
November16th to endNight
49%
900
38%
2340
17%
900
61%
900
53%
1214
December1st to 15thNight
50%
900
35%
2340
17%
900
61%
900
48%
1288
December16th to endNight
45%
960
34%
2496
16%
960
56%
960
42%
1453

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%313323346%60%
47811
Night
6%312313347%61%
47155
Cloud CoverDay
7%313323346%60%
47809
Night
6%312313346%61%
47155
TransparencyDay
24%49%23%25%13%
47509
Night
22%39%21%26%16%
46960
SeeingDay
7%5%22%33%24%6%
5641
Night
7%5%28%40%17%
15684

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
6%413313335%63%
1611
16th to endDay
5%312323345%63%
1842
February1st to 15thDay
6%322313235%65%
1750
16th to endDay
6%5%23222236%61%
1580
March1st to 15thDay
10%422312347%56%
1836
16th to endDay
7%422213345%61%
2119
April1st to 15thDay
9%312313335%61%
2150
16th to endDay
7%212313445%61%
2194
May1st to 15thDay
11%32332434456%
2331
16th to endDay
8%323423447%54%
2430
June1st to 15thDay
5%41331345%8%57%
2340
16th to endDay
421332445%8%60%
2340
July1st to 15thDay
8%222325%5%5%8%52%
2340
16th to endDay
213324349%63%
2466
August1st to 15thDay
32133235%6%9%57%
2211
16th to endDay
6%3144245%5%8%52%
2292
September1st to 15thDay
10%31333345%8%51%
2055
16th to endDay
6%33322447%60%
1828
October1st to 15thDay
11%31331313461%
1815
16th to endDay
321222223471%
1730
November1st to 15thDay
4212212336%68%
1583
16th to endDay
6%31221223468%
1620
December1st to 15thDay
8%413322336%59%
1620
16th to endDay
9%6%23223335%58%
1728
January1st to 15thNight
6%312212346%64%
2327
16th to endNight
5%222212335%67%
2391
February1st to 15thNight
7%5%1331333461%
2102
16th to endNight
7%413223246%61%
1894
March1st to 15thNight
7%5%13313346%58%
2124
16th to endNight
7%313223346%60%
2102
April1st to 15thNight
6%412323347%59%
1798
16th to endNight
7%212213346%63%
1764
May1st to 15thNight
9%312212436%61%
1619
16th to endNight
7%21232345%7%60%
1683
June1st to 15thNight
411332347%11%55%
1620
16th to endNight
31121446%12%59%
1620
July1st to 15thNight
5%2233446%9%57%
1620
16th to endNight
31121435%10%63%
1702
August1st to 15thNight
31133245%7%10%55%
1746
16th to endNight
4213325%5%5%8%55%
1910
September1st to 15thNight
10%3145%245%47%50%
1905
16th to endNight
5%21331346%7%60%
1837
October1st to 15thNight
10%31221233465%
1815
16th to endNight
311221233473%
2125
November1st to 15thNight
421112346%70%
2275
16th to endNight
5%212212335%68%
2340
December1st to 15thNight
8%312223235%63%
2340
16th to endNight
9%5%1421335%6%55%
2496

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
6%413213335%63%
1611
16th to endDay
5%312314335%63%
1842
February1st to 15thDay
6%322212225%65%
1750
16th to endDay
6%5%23223245%62%
1580
March1st to 15thDay
10%423313247%56%
1836
16th to endDay
7%413213345%62%
2117
April1st to 15thDay
9%213223236%61%
2150
16th to endDay
8%213223345%62%
2194
May1st to 15thDay
11%323324345%56%
2331
16th to endDay
8%31332345%7%55%
2430
June1st to 15thDay
6%31321445%8%57%
2340
16th to endDay
5%11232446%7%60%
2340
July1st to 15thDay
8%212325%5%5%8%53%
2340
16th to endDay
21332435%8%63%
2466
August1st to 15thDay
41123245%7%8%58%
2211
16th to endDay
6%3143345%48%52%
2292
September1st to 15thDay
11%31333435%8%51%
2055
16th to endDay
7%212422446%60%
1828
October1st to 15thDay
11%31421322461%
1815
16th to endDay
421221223471%
1730
November1st to 15thDay
432213236%69%
1583
16th to endDay
6%31221223468%
1620
December1st to 15thDay
9%413313236%59%
1620
16th to endDay
10%6%2321333458%
1728
January1st to 15thNight
6%31221225%6%64%
2327
16th to endNight
5%312213335%67%
2391
February1st to 15thNight
7%5%1322333462%
2102
16th to endNight
7%412312346%61%
1894
March1st to 15thNight
7%423413345%58%
2124
16th to endNight
8%222213345%60%
2102
April1st to 15thNight
6%31332435%7%59%
1798
16th to endNight
8%212213246%63%
1764
May1st to 15thNight
10%311312436%61%
1619
16th to endNight
7%21232345%6%60%
1683
June1st to 15thNight
421332446%11%55%
1620
16th to endNight
3112245%5%12%59%
1620
July1st to 15thNight
5%21232446%9%57%
1620
16th to endNight
31221345%9%64%
1702
August1st to 15thNight
3113325%5%7%9%55%
1746
16th to endNight
5%3133245%5%8%55%
1910
September1st to 15thNight
10%3135%245%5%6%51%
1905
16th to endNight
6%21241246%7%60%
1837
October1st to 15thNight
10%31221233465%
1815
16th to endNight
311221232473%
2125
November1st to 15thNight
421112346%71%
2275
16th to endNight
5%212213335%68%
2340
December1st to 15thNight
9%312223336%62%
2340
16th to endNight
9%6%1321335%6%55%
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
24%26%25%27%12%
1612
16th to endDay
23%26%20%32%13%
1842
February1st to 15thDay
22%27%24%26%15%
1751
16th to endDay
25%25%21%29%16%
1580
March1st to 15thDay
28%26%20%28%13%
1836
16th to endDay
24%27%26%22%15%
2119
April1st to 15thDay
25%37%16%26%20%
2150
16th to endDay
24%37%22%26%15%
2194
May1st to 15thDay
31%37%18%22%17%
2331
16th to endDay
29%49%21%20%14%
2434
June1st to 15thDay
24%5%13%23%20%12%
2340
16th to endDay
21%5%12%25%21%13%
2340
July1st to 15thDay
26%6%10%27%22%6%
2201
16th to endDay
16%5%14%33%24%5%
2311
August1st to 15thDay
20%5%16%26%22%8%
2197
16th to endDay
28%6%12%24%20%7%
2292
September1st to 15thDay
31%6%10%25%18%8%
2055
16th to endDay
23%48%23%29%10%
1828
October1st to 15thDay
28%38%21%25%12%
1815
16th to endDay
17%25%19%33%20%
1730
November1st to 15thDay
18%26%19%34%18%
1583
16th to endDay
20%2417%33%21%
1620
December1st to 15thDay
27%27%24%28%10%
1620
16th to endDay
29%27%22%28%10%
1728
January1st to 15thNight
21%27%22%30%15%
2327
16th to endNight
20%26%18%32%18%
2391
February1st to 15thNight
26%37%18%26%17%
2112
16th to endNight
24%25%21%25%20%
1894
March1st to 15thNight
27%37%18%25%17%
2124
16th to endNight
24%39%26%21%14%
2102
April1st to 15thNight
24%49%17%23%20%
1798
16th to endNight
21%48%20%27%17%
1764
May1st to 15thNight
24%5%7%17%24%20%
1620
16th to endNight
22%5%12%20%21%17%
1685
June1st to 15thNight
21%5%16%24%21%10%
1620
16th to endNight
18%414%24%21%16%
1620
July1st to 15thNight
21%6%11%26%23%10%
1530
16th to endNight
15%413%28%30%7%
1594
August1st to 15thNight
21%6%11%24%25%10%
1736
16th to endNight
24%6%13%23%21%10%
1910
September1st to 15thNight
31%5%12%21%18%9%
1905
16th to endNight
21%6%10%20%29%12%
1837
October1st to 15thNight
23%29%22%25%15%
1815
16th to endNight
14%25%19%35%21%
2125
November1st to 15thNight
15%26%23%30%21%
2275
16th to endNight
18%3417%30%25%
2340
December1st to 15thNight
25%27%22%28%14%
2340
16th to endNight
29%25%19%29%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
17%331%26%20%1
90
16th to endDay
412%39%32%8%3
96
February1st to 15thDay
45%34%40%14%1
90
16th to endDay
8%7%35%33%12%2
81
March1st to 15thDay
8%6%44%32%7%
90
16th to endDay
11%10%25%34%16%
103
April1st to 15thDay
10%15%42%26%5%
269
16th to endDay
10%15%39%22%9%1
304
May1st to 15thDay
11%8%36%32%11%
468
16th to endDay
11%7%31%29%17%2
517
June1st to 15thDay
7%423%37%22%3
495
16th to endDay
4216%36%31%8%
495
July1st to 15thDay
5%6%46%29%10%
475
16th to endDay
2429%47%15%
515
August1st to 15thDay
4437%42%10%
366
16th to endDay
6%111%33%35%12%
332
September1st to 15thDay
5%18%37%34%12%
210
16th to endDay
10%16%36%34%10%
93
October1st to 15thDay
8%324%32%27%3
90
16th to endDay
9%22%30%34%3
96
November1st to 15thDay
13%5%18%28%23%10%
90
16th to endDay
14%16%27%24%14%2
90
December1st to 15thDay
10%240%31%16%
90
16th to endDay
12%16%34%31%5%
96
January1st to 15thNight
7%6%32%40%12%
900
16th to endNight
7%5%33%44%8%
855
February1st to 15thNight
10%8%33%37%9%
704
16th to endNight
9%9%36%40%4
632
March1st to 15thNight
10%10%38%32%7%
684
16th to endNight
8%11%38%35%5%
576
April1st to 15thNight
7%12%43%33%3
539
16th to endNight
9%8%44%32%4
540
May1st to 15thNight
11%5%40%34%8%
540
16th to endNight
7%334%38%14%
563
June1st to 15thNight
5%333%42%15%
540
16th to endNight
4222%46%22%1
540
July1st to 15thNight
5%9%47%35%1
510
16th to endNight
35%40%47%2
564
August1st to 15thNight
4442%48%1
539
16th to endNight
5%16%41%43%2
573
September1st to 15thNight
10%18%43%32%2
540
16th to endNight
6%116%42%31%1
498
October1st to 15thNight
13%225%42%15%1
495
16th to endNight
35%28%41%19%
717
November1st to 15thNight
5%6%27%43%16%
875
16th to endNight
6%7%32%38%14%
900
December1st to 15thNight
11%5%29%41%10%
900
16th to endNight
12%6%31%40%8%
960
Page generated at 2017-09-18 07:38:22. Version ac04

Copyright 2017 A. Danko


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