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 2018-02-22.

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%
16646
39%
48878
32%
16608
81%
16608
63%
21268

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%
777
34%
2522
33%
776
80%
776
51%
1150
January16th to endNight
70%
832
39%
2590
35%
832
79%
832
53%
1205
February1st to 15thNight
70%
758
37%
2288
34%
757
78%
757
57%
1052
February16th to endNight
66%
660
39%
1979
38%
660
74%
660
50%
950
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%
720
39%
1888
30%
720
91%
720
73%
859
September16th to endNight
85%
716
50%
1980
41%
716
92%
716
83%
783
October1st to 15thNight
80%
720
43%
1980
36%
720
86%
720
74%
851
October16th to endNight
81%
768
47%
2346
44%
768
88%
768
69%
938
November1st to 15thNight
82%
760
39%
2470
40%
760
87%
760
66%
978
November16th to endNight
79%
780
44%
2535
44%
780
85%
780
63%
1029
December1st to 15thNight
76%
780
37%
2535
36%
780
81%
780
52%
1136
December16th to endNight
68%
832
36%
2704
34%
832
76%
832
45%
1290

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%
49330
Night
111112235%76%
49077
TransparencyDay
12%2415%27%37%
49025
Night
12%2415%27%38%
48883
SeeingDay
27%16%32%30%11%
6314
Night
2415%38%34%3
16658

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
231232335%7%64%
1746
16th to endDay
3214423336%65%
1983
February1st to 15thDay
21221325%7%70%
1901
16th to endDay
3213323346%65%
1641
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
1111122480%
2070
16th to endDay
1122387%
1980
October1st to 15thDay
11121212479%
1980
16th to endDay
11111123481%
1875
November1st to 15thDay
1211112325%76%
1719
16th to endDay
211112346%72%
1755
December1st to 15thDay
321322235%9%62%
1755
16th to endDay
4224424337%61%
1872
January1st to 15thNight
21432335%6%66%
2522
16th to endNight
4212213237%68%
2590
February1st to 15thNight
2222312335%71%
2281
16th to endNight
4212223346%66%
1979
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
11111223479%
1888
16th to endNight
111289%
1980
October1st to 15thNight
1112235%80%
1980
16th to endNight
111123381%
2346
November1st to 15thNight
11112245%77%
2470
16th to endNight
2111112136%77%
2535
December1st to 15thNight
3112323446%67%
2535
16th to endNight
5%212323346%64%
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
19%47%27%30%10%
1747
16th to endDay
22%27%24%29%14%
1983
February1st to 15thDay
14%27%20%32%21%
1901
16th to endDay
20%27%20%31%17%
1641
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%22%52%
2070
16th to endDay
6%116%29%55%
1980
October1st to 15thDay
11%1312%29%42%
1980
16th to endDay
8%2414%29%41%
1875
November1st to 15thDay
12%2420%34%25%
1719
16th to endDay
12%36%19%35%23%
1755
December1st to 15thDay
20%210%22%25%16%
1755
16th to endDay
24%49%24%26%11%
1872
January1st to 15thNight
17%46%21%31%18%
2522
16th to endNight
18%26%23%24%24%
2590
February1st to 15thNight
16%26%18%28%27%
2292
16th to endNight
19%25%18%30%23%
1979
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%21%51%
1888
16th to endNight
4116%22%63%
1980
October1st to 15thNight
9%1310%28%46%
1980
16th to endNight
8%249%22%52%
2346
November1st to 15thNight
10%2415%33%33%
2470
16th to endNight
11%2416%31%33%
2535
December1st to 15thNight
18%26%19%30%22%
2535
16th to endNight
21%39%20%29%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
10%7%15%35%27%3
135
16th to endDay
38%14%32%30%10%
255
February1st to 15thDay
36%17%31%26%14%
326
16th to endDay
6%14%18%29%24%6%
264
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%32%36%13%
315
16th to endDay
1412%26%36%18%
315
October1st to 15thDay
415%38%28%12%
315
16th to endDay
15%11%24%35%22%
216
November1st to 15thDay
2316%27%37%12%
135
16th to endDay
35%17%34%31%6%
135
December1st to 15thDay
25%14%34%36%6%
135
16th to endDay
311%13%32%32%6%
144
January1st to 15thNight
2211%47%31%3
780
16th to endNight
5%316%42%29%3
832
February1st to 15thNight
3316%43%29%3
764
16th to endNight
5%7%17%42%23%2
660
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%6%
720
16th to endNight
29%31%49%6%
716
October1st to 15thNight
1214%41%37%2
720
16th to endNight
139%33%42%9%
768
November1st to 15thNight
1110%42%40%3
760
16th to endNight
3211%38%38%5%
780
December1st to 15thNight
4211%44%32%3
780
16th to endNight
6%6%14%41%27%3
832
Page generated at 2018-02-23 08:21:31. Version ac04

Copyright 2018 A. Danko


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