Anthem
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Anthem 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
77%
16128
37%
48354
33%
16089
82%
16089
55%
22781

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
70%
763
32%
2471
32%
760
76%
760
44%
1219
January16th to endNight
63%
768
37%
2496
35%
768
72%
768
43%
1279
February1st to 15thNight
72%
698
37%
2173
34%
698
81%
698
53%
1020
February16th to endNight
68%
632
35%
1895
37%
632
73%
632
46%
993
March1st to 15thNight
69%
720
40%
1983
33%
720
76%
720
58%
973
March16th to endNight
76%
768
40%
2112
31%
768
82%
768
62%
997
April1st to 15thNight
70%
716
32%
1975
22%
716
76%
716
55%
980
April16th to endNight
71%
540
46%
1674
36%
540
81%
540
71%
652
May1st to 15thNight
76%
539
40%
1619
32%
539
81%
539
66%
689
May16th to endNight
80%
561
40%
1684
32%
561
84%
561
73%
673
June1st to 15thNight
86%
540
35%
1620
31%
540
86%
540
72%
659
June16th to endNight
92%
540
35%
1620
33%
540
92%
540
77%
636
July1st to 15thNight
86%
510
26%
1530
23%
510
86%
510
51%
754
July16th to endNight
84%
564
28%
1593
25%
531
85%
531
42%
880
August1st to 15thNight
87%
539
30%
1611
26%
536
87%
536
47%
823
August16th to endNight
85%
654
34%
1866
31%
654
85%
654
46%
1017
September1st to 15thNight
84%
720
33%
1980
30%
720
85%
720
52%
1035
September16th to endNight
86%
716
45%
1980
37%
716
89%
716
70%
871
October1st to 15thNight
81%
720
41%
2055
35%
720
84%
720
65%
916
October16th to endNight
84%
768
46%
2304
40%
768
89%
768
67%
978
November1st to 15thNight
82%
760
40%
2339
37%
760
86%
760
62%
1015
November16th to endNight
77%
780
42%
2535
42%
780
82%
780
55%
1119
December1st to 15thNight
73%
780
36%
2535
36%
780
78%
780
47%
1214
December16th to endNight
68%
832
37%
2704
37%
832
73%
832
41%
1389

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
3212212346%69%
48982
Night
3212212345%69%
48552
TransparencyDay
16%2311%25%39%
48677
Night
17%2311%23%40%
48358
SeeingDay
4419%36%27%7%
5844
Night
4110%38%38%5%
16138

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
7%21331224465%
1710
16th to endDay
8%212211237%65%
1728
February1st to 15thDay
5%312213246%66%
1685
16th to endDay
8%313312346%61%
1579
March1st to 15thDay
5%212213246%67%
1977
16th to endDay
3212213235%71%
2112
April1st to 15thDay
312213346%69%
1973
16th to endDay
21111123478%
2284
May1st to 15thDay
11112235%78%
2331
16th to endDay
21111112480%
2429
June1st to 15thDay
111111125%82%
2340
16th to endDay
1111122383%
2340
July1st to 15thDay
221232345%8%62%
2340
16th to endDay
5%323435%6%8%10%45%
2467
August1st to 15thDay
32134245%6%9%56%
2340
16th to endDay
311232446%8%61%
2333
September1st to 15thDay
4212323446%64%
1980
16th to endDay
2111122481%
1980
October1st to 15thDay
21111222478%
1905
16th to endDay
111112235%77%
1920
November1st to 15thDay
121222345%73%
1847
16th to endDay
5%21112235%72%
1755
December1st to 15thDay
5%312423445%61%
1755
16th to endDay
7%41332235%6%59%
1872
January1st to 15thNight
6%32322334464%
2471
16th to endNight
9%31332222463%
2496
February1st to 15thNight
4312212246%67%
2164
16th to endNight
7%223323445%61%
1895
March1st to 15thNight
5%212212335%70%
1983
16th to endNight
311112236%72%
2112
April1st to 15thNight
312213345%68%
1975
16th to endNight
1111122382%
1674
May1st to 15thNight
112112345%76%
1619
16th to endNight
2111112383%
1684
June1st to 15thNight
1111122481%
1620
16th to endNight
111112483%
1620
July1st to 15thNight
11134245%6%9%60%
1620
16th to endNight
22234446%8%11%48%
1701
August1st to 15thNight
2212425%5%6%9%56%
1620
16th to endNight
1135%36%46%7%57%
1866
September1st to 15thNight
22123245%6%7%61%
1980
16th to endNight
11111222479%
1980
October1st to 15thNight
3111211225%76%
2055
16th to endNight
11121123477%
2304
November1st to 15thNight
221212245%72%
2339
16th to endNight
4211212235%72%
2535
December1st to 15thNight
6%212213346%64%
2535
16th to endNight
8%314322345%60%
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
23%2213%28%29%
1711
16th to endDay
21%2218%26%28%
1728
February1st to 15thDay
20%25%14%27%29%
1685
16th to endDay
24%3117%28%23%
1579
March1st to 15thDay
19%219%31%36%
1977
16th to endDay
17%1210%32%34%
2112
April1st to 15thDay
15%2110%32%36%
1973
16th to endDay
10%217%25%52%
2284
May1st to 15thDay
10%118%26%51%
2331
16th to endDay
10%117%23%55%
2432
June1st to 15thDay
8%1417%67%
2340
16th to endDay
8%11312%73%
2340
July1st to 15thDay
18%5%8%15%18%33%
2201
16th to endDay
28%7%13%21%19%10%
2312
August1st to 15thDay
21%5%8%16%19%29%
2325
16th to endDay
18%5%6%16%29%23%
2333
September1st to 15thDay
19%36%13%24%32%
1980
16th to endDay
9%115%28%52%
1980
October1st to 15thDay
12%229%25%47%
1905
16th to endDay
11%148%25%49%
1920
November1st to 15thDay
13%2212%32%36%
1847
16th to endDay
16%1111%26%42%
1755
December1st to 15thDay
24%3416%23%27%
1755
16th to endDay
26%3319%28%18%
1872
January1st to 15thNight
23%3311%26%31%
2471
16th to endNight
26%2111%26%30%
2496
February1st to 15thNight
19%25%13%25%33%
2175
16th to endNight
25%2311%28%27%
1895
March1st to 15thNight
17%228%26%42%
1983
16th to endNight
14%2210%32%37%
2112
April1st to 15thNight
17%327%29%39%
1975
16th to endNight
8%217%23%56%
1674
May1st to 15thNight
11%227%26%50%
1620
16th to endNight
9%16%21%60%
1685
June1st to 15thNight
9%11314%69%
1620
16th to endNight
7%1138%77%
1620
July1st to 15thNight
18%5%9%15%15%35%
1530
16th to endNight
24%7%11%20%20%15%
1593
August1st to 15thNight
20%6%8%18%16%29%
1611
16th to endNight
23%6%6%14%21%28%
1866
September1st to 15thNight
19%5%7%16%21%29%
1980
16th to endNight
10%215%22%57%
1980
October1st to 15thNight
13%119%24%49%
2055
16th to endNight
11%238%18%56%
2304
November1st to 15thNight
13%2211%29%39%
2339
16th to endNight
17%238%24%44%
2535
December1st to 15thNight
21%3413%25%31%
2535
16th to endNight
26%3415%29%20%
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
26%112%39%18%2
123
16th to endDay
9%414%32%27%12%
96
February1st to 15thDay
45%21%41%26%1
200
16th to endDay
9%8%32%33%15%1
238
March1st to 15thDay
6%7%22%37%21%4
270
16th to endDay
49%33%30%19%3
288
April1st to 15thDay
7%10%26%31%15%7%
269
16th to endDay
414%41%25%10%3
270
May1st to 15thDay
112%28%35%18%3
288
16th to endDay
2431%34%22%4
330
June1st to 15thDay
1328%38%22%5%
315
16th to endDay
1114%41%29%11%
315
July1st to 15thDay
19%43%35%9%
305
16th to endDay
4430%40%18%
327
August1st to 15thDay
4434%39%16%
315
16th to endDay
1439%43%10%
332
September1st to 15thDay
6%12%39%33%6%
315
16th to endDay
4317%41%24%8%
315
October1st to 15thDay
3220%39%29%4
240
16th to endDay
211%32%38%15%
144
November1st to 15thDay
2213%45%30%5%
135
16th to endDay
8%118%33%33%5%
135
December1st to 15thDay
4316%37%34%4
135
16th to endDay
9%414%36%27%8%
144
January1st to 15thNight
7%212%45%26%5%
764
16th to endNight
10%314%40%26%4
768
February1st to 15thNight
6%213%46%28%2
704
16th to endNight
8%114%50%22%3
632
March1st to 15thNight
6%217%39%30%4
720
16th to endNight
4312%41%33%5%
768
April1st to 15thNight
4415%45%26%3
716
16th to endNight
1320%42%27%4
540
May1st to 15thNight
2315%44%31%3
540
16th to endNight
2212%40%38%4
563
June1st to 15thNight
118%44%41%2
540
16th to endNight
1337%51%6%
540
July1st to 15thNight
1329%58%6%
510
16th to endNight
1317%63%12%
564
August1st to 15thNight
3119%63%11%
539
16th to endNight
2219%62%12%
654
September1st to 15thNight
315%26%55%7%
720
16th to endNight
316%36%43%8%
716
October1st to 15thNight
319%41%39%3
720
16th to endNight
218%39%39%9%
768
November1st to 15thNight
318%43%36%6%
760
16th to endNight
5%110%40%36%6%
780
December1st to 15thNight
7%210%42%34%2
780
16th to endNight
9%210%44%28%5%
832
Page generated at 2018-01-12 20:01:26. Version ac04

Copyright 2018 A. Danko


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