Afton Canyon Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Afton Canyon Campground clear sky chart from 2005-11-05 to 2017-09-10.

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
73%
15986
39%
46846
31%
15948
80%
15948
63%
20437

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
76%
717
34%
2327
34%
716
81%
716
52%
1045
January16th to endNight
69%
768
39%
2391
34%
768
78%
768
52%
1123
February1st to 15thNight
69%
698
37%
2108
33%
697
77%
697
56%
979
February16th to endNight
65%
632
37%
1895
37%
632
73%
632
50%
915
March1st to 15thNight
66%
720
36%
2139
32%
720
77%
720
57%
952
March16th to endNight
62%
768
39%
2074
24%
768
74%
768
62%
974
April1st to 15thNight
53%
719
38%
1799
15%
719
66%
719
60%
877
April16th to endNight
59%
690
43%
1770
17%
690
74%
690
70%
789
May1st to 15thNight
61%
539
41%
1619
24%
539
71%
539
70%
631
May16th to endNight
57%
561
38%
1685
22%
561
68%
561
66%
655
June1st to 15thNight
63%
540
34%
1620
24%
540
72%
540
75%
621
June16th to endNight
68%
509
38%
1589
29%
509
77%
509
83%
567
July1st to 15thNight
83%
502
31%
1522
25%
502
87%
502
70%
627
July16th to endNight
81%
564
36%
1593
30%
531
83%
531
59%
720
August1st to 15thNight
88%
667
39%
1741
25%
664
90%
664
79%
756
August16th to endNight
90%
764
44%
1910
30%
764
92%
764
77%
878
September1st to 15thNight
89%
700
39%
1833
30%
700
91%
700
73%
834
September16th to endNight
85%
656
48%
1815
40%
656
91%
656
82%
723
October1st to 15thNight
80%
660
45%
1815
37%
660
87%
660
73%
789
October16th to endNight
80%
704
45%
2150
42%
704
88%
704
68%
866
November1st to 15thNight
82%
700
39%
2275
41%
700
88%
700
66%
898
November16th to endNight
78%
720
42%
2340
43%
720
85%
720
64%
946
December1st to 15thNight
75%
720
37%
2340
36%
720
81%
720
51%
1067
December16th to endNight
67%
768
35%
2496
33%
768
74%
768
44%
1205

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
111212235%75%
47737
Night
111112235%76%
47045
TransparencyDay
12%2415%27%37%
47432
Night
12%2415%26%38%
46851
SeeingDay
27%16%32%29%10%
5748
Night
2415%38%34%3
15998

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
22132336%7%66%
1611
16th to endDay
3314423336%63%
1830
February1st to 15thDay
31221325%7%69%
1751
16th to endDay
3213323346%64%
1579
March1st to 15thDay
111112246%74%
1821
16th to endDay
1111213347%72%
2147
April1st to 15thDay
2211212245%74%
2149
16th to endDay
111122484%
2190
May1st to 15thDay
11123484%
2331
16th to endDay
11111225%81%
2429
June1st to 15thDay
1122485%
2340
16th to endDay
111288%
2340
July1st to 15thDay
2112212335%73%
2340
16th to endDay
221231345%6%66%
2467
August1st to 15thDay
11112235%78%
2207
16th to endDay
1111234477%
2292
September1st to 15thDay
1111122481%
2012
16th to endDay
1122386%
1815
October1st to 15thDay
11121213478%
1815
16th to endDay
11111235%81%
1719
November1st to 15thDay
1111112225%77%
1584
16th to endDay
211212346%72%
1620
December1st to 15thDay
331332245%9%60%
1620
16th to endDay
4224424337%60%
1728
January1st to 15thNight
213323346%68%
2327
16th to endNight
4212223236%67%
2391
February1st to 15thNight
2222212335%70%
2101
16th to endNight
4212223346%65%
1895
March1st to 15thNight
1211212345%72%
2139
16th to endNight
112212246%73%
2074
April1st to 15thNight
112212235%75%
1799
16th to endNight
111212383%
1770
May1st to 15thNight
12125%83%
1619
16th to endNight
1122484%
1684
June1st to 15thNight
1122485%
1620
16th to endNight
11290%
1589
July1st to 15thNight
1111113335%75%
1612
16th to endNight
2113223346%69%
1701
August1st to 15thNight
11111135%82%
1750
16th to endNight
1111335%80%
1910
September1st to 15thNight
11111223480%
1833
16th to endNight
111288%
1815
October1st to 15thNight
11112235%78%
1815
16th to endNight
11111123381%
2150
November1st to 15thNight
1111223478%
2275
16th to endNight
211112135%77%
2340
December1st to 15thNight
3112323446%65%
2340
16th to endNight
5%212323346%64%
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
18%37%26%31%11%
1612
16th to endDay
23%27%23%28%15%
1830
February1st to 15thDay
15%27%21%31%21%
1751
16th to endDay
21%37%20%31%15%
1579
March1st to 15thDay
11%25%23%33%24%
1821
16th to endDay
12%36%21%35%20%
2147
April1st to 15thDay
13%2417%33%28%
2149
16th to endDay
7%1318%32%35%
2190
May1st to 15thDay
5%2315%30%42%
2331
16th to endDay
7%2312%30%43%
2432
June1st to 15thDay
6%128%21%60%
2340
16th to endDay
5%11310%77%
2340
July1st to 15thDay
13%227%15%57%
2201
16th to endDay
16%4412%21%41%
2312
August1st to 15thDay
10%217%22%55%
2192
16th to endDay
10%238%22%51%
2292
September1st to 15thDay
9%149%21%53%
2012
16th to endDay
6%116%28%55%
1815
October1st to 15thDay
12%1313%31%38%
1815
16th to endDay
8%2414%30%39%
1719
November1st to 15thDay
12%2418%34%27%
1584
16th to endDay
12%36%19%35%22%
1620
December1st to 15thDay
22%211%24%26%12%
1620
16th to endDay
25%410%25%23%10%
1728
January1st to 15thNight
16%46%20%33%19%
2327
16th to endNight
19%26%22%23%25%
2391
February1st to 15thNight
16%27%18%27%26%
2112
16th to endNight
20%25%19%30%22%
1895
March1st to 15thNight
13%35%18%30%28%
2139
16th to endNight
12%26%22%30%24%
2074
April1st to 15thNight
12%25%19%32%27%
1799
16th to endNight
7%1220%29%38%
1770
May1st to 15thNight
6%1216%31%40%
1620
16th to endNight
6%1414%34%37%
1685
June1st to 15thNight
5%129%21%58%
1620
16th to endNight
45%11%77%
1589
July1st to 15thNight
9%238%16%59%
1522
16th to endNight
15%2412%20%44%
1593
August1st to 15thNight
6%128%21%58%
1741
16th to endNight
7%248%22%55%
1910
September1st to 15thNight
9%249%20%52%
1833
16th to endNight
4116%21%63%
1815
October1st to 15thNight
9%1411%30%43%
1815
16th to endNight
8%2410%23%50%
2150
November1st to 15thNight
10%2315%32%35%
2275
16th to endNight
11%25%16%30%34%
2340
December1st to 15thNight
19%27%20%31%18%
2340
16th to endNight
21%39%21%28%14%
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
11%8%20%44%15%
90
16th to endDay
49%17%34%24%10%
198
February1st to 15thDay
47%18%32%26%10%
266
16th to endDay
6%14%19%29%22%6%
238
March1st to 15thDay
214%18%29%25%9%
270
16th to endDay
314%21%28%24%7%
288
April1st to 15thDay
419%22%25%21%5%
269
16th to endDay
220%28%25%17%6%
270
May1st to 15thDay
210%24%30%26%5%
288
16th to endDay
110%20%35%25%6%
330
June1st to 15thDay
18%21%34%27%6%
315
16th to endDay
1314%32%37%10%
315
July1st to 15thDay
111%38%31%15%
305
16th to endDay
217%33%42%12%
327
August1st to 15thDay
112%38%34%12%
315
16th to endDay
119%33%33%20%
332
September1st to 15thDay
2212%30%37%14%
294
16th to endDay
149%23%39%20%
255
October1st to 15thDay
15%16%33%29%14%
255
16th to endDay
1414%26%37%15%
162
November1st to 15thDay
5%14%22%38%18%
90
16th to endDay
5%5%23%38%25%1
90
December1st to 15thDay
35%17%40%30%3
90
16th to endDay
5%13%15%40%22%2
96
January1st to 15thNight
2211%48%30%3
720
16th to endNight
5%316%43%28%2
768
February1st to 15thNight
3316%44%29%2
704
16th to endNight
5%7%18%42%23%3
632
March1st to 15thNight
27%18%41%25%3
720
16th to endNight
27%24%36%26%2
768
April1st to 15thNight
212%27%32%21%2
719
16th to endNight
11%25%35%22%3
690
May1st to 15thNight
19%27%36%23%1
540
16th to endNight
15%24%33%24%1
563
June1st to 15thNight
7%27%38%25%1
540
16th to endNight
127%42%26%
509
July1st to 15thNight
211%44%39%1
502
16th to endNight
39%36%49%
564
August1st to 15thNight
17%37%50%3
667
16th to endNight
1426%56%10%
764
September1st to 15thNight
15%30%55%7%
700
16th to endNight
28%30%49%7%
656
October1st to 15thNight
1214%41%37%2
660
16th to endNight
149%35%41%8%
704
November1st to 15thNight
1210%40%41%4
700
16th to endNight
3311%39%36%5%
720
December1st to 15thNight
4311%45%31%3
720
16th to endNight
6%6%14%42%26%2
768
Page generated at 2017-09-11 16:35:20. Version ac04

Copyright 2017 A. Danko


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