Ammon
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ammon clear sky chart from 2005-11-06 to 2024-03-08.

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
47%
24092
19%
80440
15%
24000
52%
24000
25%
50988

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 10thNight
35%
805
11%
4428
8%
793
39%
793
9%
3122
January11th to 20thNight
36%
757
11%
4297
12%
740
41%
740
9%
3253
January21st to endNight
35%
831
8%
4489
10%
814
39%
814
9%
3236
February1st to 10thNight
31%
760
11%
2470
8%
760
36%
760
15%
1799
February11th to 20thNight
35%
743
13%
2389
11%
740
41%
740
18%
1668
February21st to endNight
33%
628
12%
1884
9%
628
39%
628
16%
1406
March1st to 10thNight
37%
750
16%
2151
11%
750
43%
750
20%
1541
March11th to 20thNight
44%
720
21%
1980
14%
720
50%
720
29%
1293
March21st to endNight
39%
792
14%
2178
7%
792
44%
792
21%
1568
April1st to 10thNight
42%
678
17%
1916
10%
678
48%
678
24%
1309
April11th to 20thNight
39%
533
20%
1601
14%
533
43%
533
25%
1036
April21st to endNight
49%
540
22%
1620
16%
540
54%
540
29%
1001
May1st to 10thNight
50%
540
19%
1620
15%
540
53%
540
30%
997
May11th to 20thNight
56%
531
19%
1595
17%
531
58%
531
33%
954
May21st to endNight
53%
582
15%
1579
12%
582
56%
582
28%
1046
June1st to 10thNight
57%
428
19%
1328
15%
428
64%
428
34%
745
June11th to 20thNight
47%
360
23%
1260
19%
360
59%
360
33%
665
June21st to endNight
70%
360
31%
1260
34%
360
79%
360
54%
538
July1st to 10thNight
72%
350
28%
1244
32%
350
80%
350
52%
527
July11th to 20thNight
70%
366
31%
1410
36%
366
79%
366
58%
530
July21st to endNight
73%
591
29%
1674
25%
558
77%
558
54%
799
August1st to 10thNight
68%
537
28%
1602
22%
534
73%
534
45%
840
August11th to 20thNight
75%
534
37%
1602
28%
534
79%
534
57%
742
August21st to endNight
65%
594
38%
1782
29%
594
71%
594
51%
863
September1st to 10thNight
66%
630
33%
1867
24%
630
74%
630
52%
920
September11th to 20thNight
63%
720
33%
1980
24%
720
71%
720
47%
1071
September21st to endNight
61%
720
33%
1980
23%
720
68%
720
46%
1075
October1st to 10thNight
58%
720
25%
2078
18%
720
63%
720
38%
1180
October11th to 20thNight
53%
720
29%
2160
21%
720
60%
720
37%
1198
October21st to endNight
52%
792
25%
2461
19%
792
60%
792
32%
1453
November1st to 10thNight
44%
740
21%
2405
18%
740
49%
740
25%
1494
November11th to 20thNight
39%
859
18%
2569
12%
859
45%
859
23%
1724
November21st to endNight
44%
950
16%
2660
10%
950
48%
950
26%
1774
December1st to 10thNight
34%
950
11%
2660
7%
950
37%
950
19%
1963
December11th to 20thNight
31%
949
12%
3205
6%
948
35%
948
14%
2368
December21st to endNight
27%
1032
6%
5056
5%
1026
30%
1026
9%
3290

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
8%8%36%5%3445%7%47%
78529
Night
10%10%46%5%3445%6%43%
81032
TransparencyDay
39%410%22%17%8%
78238
Night
43%411%21%15%7%
80843
SeeingDay
13%12%26%28%16%4
14318
Night
14%8%23%35%17%3
24129

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 10thDay
11%21%7%9%5%3445%6%24%
2457
11th to 20thDay
13%15%7%11%6%34345%28%
2636
21st to endDay
16%19%6%9%6%34445%27%
3146
February1st to 10thDay
11%15%5%11%8%46%5%45%26%
1710
11th to 20thDay
12%13%6%9%6%45%5%5%7%29%
1677
21st to endDay
7%15%5%9%7%35%5%5%6%32%
1570
March1st to 10thDay
8%11%5%10%7%45%448%34%
1968
11th to 20thDay
8%11%36%6%36%6%6%9%37%
1980
21st to endDay
11%14%6%8%7%35%5%5%7%30%
2178
April1st to 10thDay
11%12%37%5%45%5%6%8%36%
2041
11th to 20thDay
7%9%47%5%345%5%7%42%
2307
21st to endDay
9%8%46%5%35%5%5%8%41%
2340
May1st to 10thDay
7%6%36%5%45%5%6%8%45%
2340
11th to 20thDay
7%6%26%6%35%6%6%9%43%
2301
21st to endDay
11%7%35%6%46%6%7%8%37%
2694
June1st to 10thDay
8%4245%35%5%7%8%49%
2628
11th to 20thDay
7%5%15%4335%5%8%53%
2700
21st to endDay
2213222347%71%
2700
July1st to 10thDay
221232345%8%68%
2676
11th to 20thDay
2212213446%72%
2501
21st to endDay
331332445%6%65%
2545
August1st to 10thDay
431343445%6%63%
2328
11th to 20thDay
3212322345%73%
2299
21st to endDay
331332345%6%67%
2574
September1st to 10thDay
4312322246%70%
2090
11th to 20thDay
6%413423446%63%
1980
21st to endDay
7%323323346%63%
1980
October1st to 10thDay
11%5%25%4245%5%5%51%
1882
11th to 20thDay
8%6%245%34446%55%
1800
21st to endDay
8%6%245%3446%6%50%
1893
November1st to 10thDay
13%10%45%42435%6%43%
1674
11th to 20thDay
12%10%36%5%345%6%7%40%
1590
21st to endDay
10%12%5%7%434445%42%
1520
December1st to 10thDay
13%13%6%10%6%24445%32%
1520
11th to 20thDay
13%13%5%10%9%45%5%5%6%26%
1862
21st to endDay
10%13%47%5%345%5%8%34%
2442
January1st to 10thNight
11%17%7%11%5%34446%28%
4502
11th to 20thNight
17%20%6%10%6%33345%24%
4324
21st to endNight
17%20%5%8%6%3333426%
4521
February1st to 10thNight
13%14%5%7%6%45%5%5%6%30%
2470
11th to 20thNight
13%14%5%7%5%35%35%6%35%
2388
21st to endNight
9%12%7%10%7%45%6%5%6%29%
1884
March1st to 10thNight
9%13%5%7%6%445%6%6%34%
2151
11th to 20thNight
6%9%46%6%35%46%9%41%
1980
21st to endNight
10%10%48%7%45%5%6%7%34%
2178
April1st to 10thNight
10%10%46%6%35%5%6%7%39%
1916
11th to 20thNight
8%10%36%5%45%46%7%41%
1601
21st to endNight
9%8%25%5%3445%6%48%
1620
May1st to 10thNight
7%7%35%435%5%5%8%46%
1620
11th to 20thNight
8%6%245%345%7%9%46%
1594
21st to endNight
12%6%346%35%5%6%9%41%
1579
June1st to 10thNight
6%4245%35%5%6%8%51%
1328
11th to 20thNight
8%425%43436%7%53%
1260
21st to endNight
2223223347%70%
1260
July1st to 10thNight
211232346%10%65%
1280
11th to 20thNight
111222335%7%73%
1458
21st to endNight
32224335%5%8%64%
1773
August1st to 10thNight
431443446%8%58%
1611
11th to 20thNight
221232445%7%67%
1602
21st to endNight
3313323446%67%
1782
September1st to 10thNight
4313323345%69%
1867
11th to 20thNight
6%31333445%7%61%
1980
21st to endNight
8%413323346%63%
1980
October1st to 10thNight
10%5%2442445%5%55%
2078
11th to 20thNight
9%6%24324345%57%
2160
21st to endNight
8%6%245%335%5%7%50%
2461
November1st to 10thNight
12%8%36%3245%5%7%45%
2405
11th to 20thNight
11%11%46%6%3445%7%40%
2569
21st to endNight
10%10%47%5%35%45%7%41%
2660
December1st to 10thNight
12%15%5%9%7%33446%33%
2660
11th to 20thNight
13%14%6%9%7%34446%30%
3316
21st to endNight
11%14%5%9%7%45%445%34%
5214

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 10thDay
62%313%18%31
2457
11th to 20thDay
61%313%16%7%1
2636
21st to endDay
62%413%15%6%1
3146
February1st to 10thDay
61%5%12%18%5%1
1710
11th to 20thDay
56%413%19%7%1
1686
21st to endDay
56%7%11%18%8%1
1570
March1st to 10thDay
53%5%11%21%8%2
1968
11th to 20thDay
47%413%24%9%2
1980
21st to endDay
57%5%12%19%7%
2178
April1st to 10thDay
49%5%13%17%13%2
2041
11th to 20thDay
43%6%9%27%13%3
2310
21st to endDay
43%5%10%27%14%1
2340
May1st to 10thDay
38%6%9%26%19%2
2340
11th to 20thDay
40%5%8%30%14%2
2304
21st to endDay
46%6%10%26%11%1
2694
June1st to 10thDay
34%412%31%18%1
2628
11th to 20thDay
32%48%23%22%10%
2700
21st to endDay
16%3324%37%16%
2700
July1st to 10thDay
16%3318%36%23%
2603
11th to 20thDay
15%3315%29%35%
2426
21st to endDay
22%3414%26%31%
2404
August1st to 10thDay
24%3417%29%23%
2313
11th to 20thDay
16%3319%36%23%
2299
21st to endDay
20%3419%34%20%
2574
September1st to 10thDay
18%36%18%32%23%
2090
11th to 20thDay
24%37%25%28%13%
1980
21st to endDay
24%37%28%30%8%
1980
October1st to 10thDay
37%310%29%16%6%
1882
11th to 20thDay
34%314%32%14%3
1800
21st to endDay
36%415%26%18%1
1893
November1st to 10thDay
46%414%23%11%2
1674
11th to 20thDay
45%417%24%8%2
1590
21st to endDay
46%318%22%10%2
1520
December1st to 10thDay
56%5%13%17%6%3
1520
11th to 20thDay
62%412%19%3
1860
21st to endDay
51%314%22%10%1
2442
January1st to 10thNight
59%310%21%6%
4502
11th to 20thNight
64%411%15%41
4324
21st to endNight
62%216%14%41
4521
February1st to 10thNight
56%5%14%18%6%1
2470
11th to 20thNight
52%414%21%9%1
2389
21st to endNight
57%5%11%19%6%2
1884
March1st to 10thNight
51%5%11%23%8%1
2151
11th to 20thNight
41%413%27%13%2
1980
21st to endNight
51%6%13%22%7%1
2178
April1st to 10thNight
46%5%12%20%14%3
1916
11th to 20thNight
43%412%24%14%2
1601
21st to endNight
38%410%29%18%1
1620
May1st to 10thNight
37%5%8%29%19%2
1620
11th to 20thNight
36%412%27%19%3
1595
21st to endNight
41%6%13%25%13%2
1579
June1st to 10thNight
31%5%13%25%24%2
1328
11th to 20thNight
29%5%9%20%27%10%
1260
21st to endNight
17%2420%33%23%
1260
July1st to 10thNight
16%4418%30%28%
1244
11th to 20thNight
13%3215%27%41%
1410
21st to endNight
19%3413%26%36%
1674
August1st to 10thNight
25%35%17%23%26%
1602
11th to 20thNight
17%3217%35%26%
1602
21st to endNight
20%3416%28%28%
1782
September1st to 10thNight
20%3413%30%30%
1867
11th to 20thNight
24%36%23%26%17%
1980
21st to endNight
25%35%25%32%10%
1980
October1st to 10thNight
32%210%27%22%7%
2078
11th to 20thNight
31%210%35%17%3
2160
21st to endNight
35%413%27%19%2
2461
November1st to 10thNight
42%413%26%13%2
2405
11th to 20thNight
46%414%24%10%2
2569
21st to endNight
45%415%23%11%2
2660
December1st to 10thNight
54%5%16%16%7%3
2660
11th to 20thNight
57%415%19%5%
3317
21st to endNight
55%211%20%11%1
5214

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 10thDay
27%18%13%24%12%4
180
11th to 20thDay
20%11%27%23%17%2
207
21st to endDay
20%10%27%30%11%2
297
February1st to 10thDay
20%20%31%22%6%1
270
11th to 20thDay
21%17%33%19%9%1
282
21st to endDay
17%21%31%22%8%1
382
March1st to 10thDay
18%23%31%21%6%1
449
11th to 20thDay
14%20%28%29%9%1
420
21st to endDay
21%22%33%18%7%
462
April1st to 10thDay
20%19%27%23%8%2
420
11th to 20thDay
17%20%34%19%8%1
412
21st to endDay
17%15%28%25%13%3
420
May1st to 10thDay
11%14%30%30%13%3
423
11th to 20thDay
13%14%29%25%18%3
448
21st to endDay
15%9%21%30%18%7%
649
June1st to 10thDay
9%12%24%28%20%7%
630
11th to 20thDay
14%14%27%30%14%2
630
21st to endDay
5%6%26%36%21%7%
630
July1st to 10thDay
5%6%22%36%26%5%
598
11th to 20thDay
38%28%40%18%3
444
21st to endDay
4320%35%30%8%
487
August1st to 10thDay
6%5%28%32%23%6%
447
11th to 20thDay
5%424%33%26%8%
437
21st to endDay
5%11%24%30%22%8%
495
September1st to 10thDay
5%8%26%30%25%6%
450
11th to 20thDay
9%11%25%29%20%6%
450
21st to endDay
10%10%26%27%22%5%
450
October1st to 10thDay
13%11%18%28%24%6%
352
11th to 20thDay
12%18%20%23%17%10%
270
21st to endDay
15%15%27%31%10%3
297
November1st to 10thDay
24%11%26%23%9%6%
270
11th to 20thDay
15%14%29%26%13%3
270
21st to endDay
16%12%27%30%13%2
270
December1st to 10thDay
23%12%24%26%11%4
270
11th to 20thDay
25%10%33%21%11%1
252
21st to endDay
25%14%26%21%11%4
198
January1st to 10thNight
22%9%19%31%17%1
817
11th to 20thNight
23%8%23%28%16%3
760
21st to endNight
22%6%20%36%14%2
836
February1st to 10thNight
20%11%28%28%12%1
760
11th to 20thNight
21%10%26%31%11%3
744
21st to endNight
14%13%28%31%11%3
628
March1st to 10thNight
15%13%27%32%12%2
750
11th to 20thNight
12%8%29%34%15%2
720
21st to endNight
14%10%27%37%11%1
792
April1st to 10thNight
16%9%25%35%13%1
678
11th to 20thNight
15%11%29%34%9%2
533
21st to endNight
14%7%23%37%18%2
540
May1st to 10thNight
12%8%24%36%20%1
540
11th to 20thNight
12%6%19%35%24%4
531
21st to endNight
13%7%19%38%19%3
584
June1st to 10thNight
9%7%21%34%25%4
428
11th to 20thNight
10%7%29%33%19%1
360
21st to endNight
4220%42%26%7%
360
July1st to 10thNight
3119%43%27%6%
350
11th to 20thNight
2122%49%25%1
366
21st to endNight
3315%46%30%4
591
August1st to 10thNight
7%216%47%26%2
537
11th to 20thNight
3115%47%30%3
534
21st to endNight
5%420%41%26%4
594
September1st to 10thNight
5%321%41%24%5%
630
11th to 20thNight
7%320%37%27%6%
720
21st to endNight
11%320%38%21%7%
720
October1st to 10thNight
12%5%19%38%23%2
720
11th to 20thNight
12%8%21%36%19%4
720
21st to endNight
12%9%21%40%14%4
792
November1st to 10thNight
16%10%24%31%16%3
740
11th to 20thNight
17%10%27%32%14%1
859
21st to endNight
15%9%22%34%17%2
950
December1st to 10thNight
20%9%25%35%11%1
950
11th to 20thNight
24%9%23%30%12%1
950
21st to endNight
27%11%22%28%10%2
1045
Page generated at 2024-03-05 04:24:01. Version ac07

Copyright © 2024 Attilla Danko.


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