Canyonlands National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Canyonlands National Park clear sky chart from 2005-11-05 to 2018-01-12.

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
68%
16216
28%
48542
24%
16180
72%
16180
43%
25639

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%
760
25%
2471
26%
760
74%
760
38%
1319
January16th to endNight
65%
768
28%
2496
29%
768
68%
768
33%
1433
February1st to 15thNight
63%
700
20%
2288
21%
700
66%
700
34%
1293
February16th to endNight
58%
632
29%
1910
24%
632
66%
632
36%
1090
March1st to 15thNight
65%
720
31%
1980
25%
720
70%
720
45%
1070
March16th to endNight
62%
768
27%
2112
18%
768
68%
768
41%
1181
April1st to 15thNight
49%
604
24%
1863
17%
604
58%
604
35%
1031
April16th to endNight
53%
540
31%
1716
22%
540
64%
540
39%
870
May1st to 15thNight
59%
539
27%
1619
20%
539
64%
539
40%
873
May16th to endNight
61%
561
27%
1685
20%
561
68%
561
47%
820
June1st to 15thNight
68%
540
29%
1497
23%
540
73%
540
57%
716
June16th to endNight
77%
540
32%
1551
29%
540
82%
540
67%
686
July1st to 15thNight
74%
510
18%
1530
16%
510
76%
510
42%
837
July16th to endNight
82%
564
22%
1593
20%
531
82%
531
38%
901
August1st to 15thNight
76%
539
25%
1611
22%
536
77%
536
44%
860
August16th to endNight
79%
573
34%
1817
32%
573
81%
573
46%
923
September1st to 15thNight
75%
606
32%
1866
30%
606
79%
606
48%
920
September16th to endNight
76%
716
39%
1980
29%
716
81%
716
62%
930
October1st to 15thNight
71%
720
34%
2148
25%
720
78%
720
54%
1005
October16th to endNight
73%
768
40%
2304
32%
768
78%
768
54%
1089
November1st to 15thNight
70%
760
32%
2335
28%
760
72%
760
47%
1170
November16th to endNight
70%
887
34%
2642
31%
887
74%
887
50%
1300
December1st to 15thNight
67%
975
23%
2730
21%
975
69%
975
42%
1534
December16th to endNight
61%
926
17%
2798
16%
926
63%
926
26%
1788

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
231342446%8%56%
48771
Night
33134245%5%7%56%
48737
TransparencyDay
23%5%10%21%22%16%
48466
Night
24%410%22%23%14%
48543
SeeingDay
6%11%22%32%21%5%
5755
Night
5%415%38%30%5%
16227

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
35%26%8%6%7%8%9%11%29%
1710
16th to endDay
5%3147%47%7%8%10%39%
1728
February1st to 15thDay
3425%9%45%7%6%13%37%
1575
16th to endDay
35%25%5%25%46%9%47%
1560
March1st to 15thDay
2424425%45%9%54%
1980
16th to endDay
232342447%8%55%
2112
April1st to 15thDay
24135%35%446%58%
2084
16th to endDay
221343445%7%60%
2243
May1st to 15thDay
23233245%7%7%56%
2331
16th to endDay
221232435%8%61%
2429
June1st to 15thDay
21221235%6%71%
2454
16th to endDay
11111223478%
2401
July1st to 15thDay
2213335%5%7%9%54%
2340
16th to endDay
23245%45%7%8%11%45%
2467
August1st to 15thDay
3324445%6%7%8%49%
2340
16th to endDay
22134245%6%9%58%
2384
September1st to 15thDay
321342446%8%59%
2092
16th to endDay
211212336%72%
1980
October1st to 15thDay
2213323346%65%
1812
16th to endDay
2312212335%70%
1920
November1st to 15thDay
3213312236%69%
1850
16th to endDay
2314313246%65%
1631
December1st to 15thDay
28%245%35%5%6%8%47%
1560
16th to endDay
37%26%9%5%9%7%7%9%29%
1788
January1st to 15thNight
3424435%5%7%10%48%
2471
16th to endNight
46%25%6%35%5%5%7%47%
2496
February1st to 15thNight
25%25%7%35%5%6%8%45%
2277
16th to endNight
25%25%5%345%7%6%49%
1910
March1st to 15thNight
33233245%5%7%57%
1980
16th to endNight
3214335%5%6%7%54%
2112
April1st to 15thNight
3325%4346%5%8%52%
1863
16th to endNight
33133335%6%6%58%
1716
May1st to 15thNight
2324435%45%6%56%
1619
16th to endNight
22133245%5%8%60%
1684
June1st to 15thNight
21231245%6%69%
1497
16th to endNight
12222336%73%
1551
July1st to 15thNight
12145%35%5%7%11%50%
1620
16th to endNight
12135%47%6%10%10%45%
1701
August1st to 15thNight
22145%246%6%10%51%
1620
16th to endNight
22134245%6%9%56%
1817
September1st to 15thNight
321342445%8%60%
1866
16th to endNight
312212335%72%
1980
October1st to 15thNight
2112323346%67%
2148
16th to endNight
3312212345%68%
2304
November1st to 15thNight
3312314446%64%
2335
16th to endNight
3313213346%66%
2642
December1st to 15thNight
45%2432345%8%55%
2730
16th to endNight
5%7%36%6%47%6%5%9%37%
2798

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
35%8%18%30%4
1711
16th to endDay
30%6%18%32%11%
1728
February1st to 15thDay
31%7%21%24%13%2
1575
16th to endDay
29%5%9%30%22%3
1560
March1st to 15thDay
24%5%8%31%24%5%
1980
16th to endDay
24%5%10%27%25%6%
2112
April1st to 15thDay
25%47%23%26%12%
2084
16th to endDay
21%47%24%29%12%
2243
May1st to 15thDay
22%6%7%18%32%13%
2331
16th to endDay
19%49%17%29%19%
2432
June1st to 15thDay
13%2410%26%40%
2454
16th to endDay
10%135%20%58%
2401
July1st to 15thDay
23%7%9%13%15%30%
2201
16th to endDay
28%9%11%17%14%18%
2312
August1st to 15thDay
27%8%10%17%13%22%
2325
16th to endDay
21%6%8%16%24%22%
2384
September1st to 15thDay
21%5%9%14%21%27%
2092
16th to endDay
13%36%16%34%24%
1980
October1st to 15thDay
20%36%23%32%13%
1812
16th to endDay
17%37%26%37%7%
1920
November1st to 15thDay
18%29%32%30%7%
1850
16th to endDay
20%311%38%23%2
1631
December1st to 15thDay
29%7%19%31%11%
1560
16th to endDay
41%9%22%19%6%
1788
January1st to 15thNight
25%6%18%34%14%
2471
16th to endNight
33%413%31%15%2
2496
February1st to 15thNight
31%5%16%26%15%4
2288
16th to endNight
29%5%9%27%24%3
1910
March1st to 15thNight
22%5%8%29%26%7%
1980
16th to endNight
25%5%9%23%28%6%
2112
April1st to 15thNight
28%47%18%25%14%
1863
16th to endNight
23%47%19%32%12%
1716
May1st to 15thNight
26%48%16%29%14%
1620
16th to endNight
18%5%9%18%32%15%
1685
June1st to 15thNight
15%349%28%38%
1497
16th to endNight
11%236%17%58%
1551
July1st to 15thNight
25%6%10%14%13%29%
1530
16th to endNight
27%7%12%19%15%17%
1593
August1st to 15thNight
23%6%11%19%18%21%
1611
16th to endNight
21%6%8%15%22%26%
1817
September1st to 15thNight
20%49%14%17%33%
1866
16th to endNight
14%37%17%29%28%
1980
October1st to 15thNight
16%37%20%32%18%
2148
16th to endNight
18%27%18%38%14%
2304
November1st to 15thNight
22%38%22%33%9%
2335
16th to endNight
20%38%29%31%6%
2642
December1st to 15thNight
26%5%14%32%19%2
2730
16th to endNight
38%7%19%27%6%
2798

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
21%8%17%26%22%3
123
16th to endDay
7%5%5%48%28%5%
96
February1st to 15thDay
12%5%344%23%11%
90
16th to endDay
11%22%20%27%14%3
177
March1st to 15thDay
5%17%22%32%19%1
270
16th to endDay
7%23%30%27%9%1
288
April1st to 15thDay
10%23%29%20%12%3
269
16th to endDay
11%25%28%23%10%
270
May1st to 15thDay
7%18%34%25%12%2
288
16th to endDay
6%15%31%26%16%3
330
June1st to 15thDay
411%26%31%20%5%
429
16th to endDay
36%23%36%24%5%
376
July1st to 15thDay
5%321%37%26%5%
305
16th to endDay
3217%37%32%7%
327
August1st to 15thDay
7%416%41%24%6%
315
16th to endDay
4316%35%32%7%
332
September1st to 15thDay
27%28%32%21%7%
315
16th to endDay
5%13%19%29%24%7%
315
October1st to 15thDay
6%12%17%29%21%11%
147
16th to endDay
11%9%12%35%24%6%
144
November1st to 15thDay
29%19%37%25%5%
135
16th to endDay
8%5%26%39%17%1
135
December1st to 15thDay
37%21%42%20%4
135
16th to endDay
11%5%13%41%25%2
144
January1st to 15thNight
6%410%41%30%6%
764
16th to endNight
7%312%42%27%5%
768
February1st to 15thNight
6%413%44%26%4
704
16th to endNight
5%7%20%46%18%2
632
March1st to 15thNight
48%17%40%27%2
720
16th to endNight
5%8%19%38%25%3
768
April1st to 15thNight
6%11%28%34%16%2
604
16th to endNight
6%12%25%30%21%3
540
May1st to 15thNight
46%22%41%20%4
540
16th to endNight
38%22%36%23%6%
563
June1st to 15thNight
35%18%40%29%3
540
16th to endNight
1116%43%32%4
540
July1st to 15thNight
210%29%49%7%
510
16th to endNight
35%27%53%9%
564
August1st to 15thNight
418%34%43%7%
539
16th to endNight
419%30%43%11%
573
September1st to 15thNight
5%28%33%40%9%
606
16th to endNight
4112%29%38%12%
716
October1st to 15thNight
35%15%42%27%6%
720
16th to endNight
5%214%33%35%9%
768
November1st to 15thNight
5%315%36%33%5%
760
16th to endNight
6%5%13%36%31%6%
887
December1st to 15thNight
8%414%46%22%4
975
16th to endNight
10%7%12%39%26%4
926
Page generated at 2018-01-12 20:01:37. Version ac04

Copyright 2018 A. Danko


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