A & O Farm
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the A & O Farm clear sky chart from 2005-11-06 to 2024-01-10.

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
38%
24030
17%
74784
12%
23983
45%
23983
21%
51049

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
19%
759
13%
2458
6%
757
28%
757
11%
1885
January11th to 20thNight
18%
720
11%
2340
4%
720
27%
720
10%
1824
January21st to endNight
18%
792
13%
2574
7%
792
27%
792
12%
1938
February1st to 10thNight
22%
720
12%
2340
7%
720
28%
720
13%
1746
February11th to 20thNight
16%
700
11%
2186
5%
700
24%
700
12%
1641
February21st to endNight
17%
592
15%
1776
6%
592
26%
592
13%
1343
March1st to 10thNight
24%
720
20%
2004
9%
720
34%
720
20%
1394
March11th to 20thNight
24%
720
18%
1980
9%
720
31%
720
18%
1413
March21st to endNight
24%
792
16%
2178
7%
792
32%
792
18%
1567
April1st to 10thNight
25%
720
16%
1962
7%
720
33%
720
22%
1366
April11th to 20thNight
32%
628
21%
1692
9%
628
40%
628
27%
1113
April21st to endNight
31%
540
20%
1620
9%
540
41%
540
24%
1080
May1st to 10thNight
34%
540
15%
1620
7%
540
40%
540
20%
1128
May11th to 20thNight
39%
531
14%
1593
8%
531
44%
531
21%
1122
May21st to endNight
55%
582
17%
1745
11%
582
60%
582
31%
1067
June1st to 10thNight
55%
540
18%
1620
15%
540
59%
540
31%
995
June11th to 20thNight
54%
540
15%
1620
13%
540
58%
540
28%
1031
June21st to endNight
58%
540
17%
1620
14%
540
62%
540
31%
980
July1st to 10thNight
60%
525
15%
1575
14%
525
62%
525
28%
1019
July11th to 20thNight
63%
522
17%
1566
13%
522
66%
522
34%
930
July21st to endNight
61%
591
17%
1672
15%
558
63%
558
27%
1089
August1st to 10thNight
65%
537
19%
1600
17%
534
65%
534
30%
1004
August11th to 20thNight
63%
534
21%
1598
18%
534
65%
534
29%
1015
August21st to endNight
67%
648
24%
1836
19%
648
69%
648
36%
1101
September1st to 10thNight
63%
720
24%
1916
17%
720
66%
720
37%
1183
September11th to 20thNight
64%
720
29%
1980
21%
720
68%
720
38%
1169
September21st to endNight
50%
720
25%
1980
19%
720
56%
720
29%
1277
October1st to 10thNight
52%
720
23%
2092
20%
720
57%
720
32%
1281
October11th to 20thNight
41%
720
23%
2160
17%
720
51%
720
28%
1349
October21st to endNight
38%
792
24%
2376
19%
792
46%
792
23%
1584
November1st to 10thNight
43%
740
25%
2342
21%
740
51%
740
29%
1397
November11th to 20thNight
32%
760
21%
2470
13%
760
43%
760
19%
1641
November21st to endNight
31%
760
20%
2481
13%
760
40%
760
18%
1713
December1st to 10thNight
23%
760
12%
2660
8%
760
28%
760
11%
2016
December11th to 20thNight
25%
759
12%
3068
9%
759
31%
759
11%
2239
December21st to endNight
22%
826
9%
4484
7%
817
29%
817
7%
3409

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
16%9%46%6%345%5%7%34%
74587
Night
16%9%46%5%3445%7%36%
75078
TransparencyDay
49%5%11%21%12%2
74309
Night
48%5%11%21%14%2
74875
SeeingDay
22%12%26%22%13%5%
13752
Night
21%10%24%29%15%2
24047

By Month

Percentage Cloud Cover SE (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
19%13%6%11%8%34445%22%
1697
11th to 20thDay
21%17%5%11%6%3344421%
1620
21st to endDay
20%18%6%10%6%33435%23%
1782
February1st to 10thDay
24%12%5%9%7%43345%25%
1620
11th to 20thDay
20%14%410%5%3445%7%24%
1661
21st to endDay
22%13%47%5%3435%5%29%
1480
March1st to 10thDay
17%11%5%5%5%33446%36%
1954
11th to 20thDay
20%10%5%7%6%43446%32%
1980
21st to endDay
20%10%47%5%345%46%31%
2178
April1st to 10thDay
15%9%37%6%45%46%7%35%
1998
11th to 20thDay
17%9%35%5%34447%39%
2230
21st to endDay
20%7%36%6%35%5%6%7%33%
2340
May1st to 10thDay
19%8%47%6%5%5%5%6%6%30%
2340
11th to 20thDay
19%8%37%6%45%5%5%6%31%
2301
21st to endDay
10%5%36%6%35%6%7%10%38%
2531
June1st to 10thDay
13%6%35%5%445%6%9%39%
2340
11th to 20thDay
11%6%36%6%46%5%7%10%37%
2340
21st to endDay
12%5%35%6%35%8%6%10%37%
2340
July1st to 10thDay
11%6%26%7%46%6%7%8%36%
2340
11th to 20thDay
11%5%26%6%46%6%6%8%39%
2340
21st to endDay
14%6%36%5%46%5%7%9%36%
2547
August1st to 10thDay
10%5%25%7%5%7%6%9%10%34%
2327
11th to 20thDay
11%5%36%6%46%7%8%10%34%
2303
21st to endDay
11%5%25%6%45%6%6%9%41%
2502
September1st to 10thDay
15%5%245%3445%7%46%
2041
11th to 20thDay
11%5%35%4345%5%8%46%
1980
21st to endDay
18%8%25%433446%42%
1980
October1st to 10thDay
15%6%25%4335%5%9%42%
1868
11th to 20thDay
17%7%26%5%44446%41%
1800
21st to endDay
22%7%36%433346%38%
1980
November1st to 10thDay
12%6%25%434446%50%
1733
11th to 20thDay
16%11%45%5%235%5%6%36%
1710
21st to endDay
17%10%46%6%34446%35%
1689
December1st to 10thDay
24%14%7%8%6%34345%23%
1520
11th to 20thDay
21%15%6%8%5%23346%26%
2071
21st to endDay
23%18%5%8%7%445%5%5%17%
3124
January1st to 10thNight
18%14%6%9%8%44445%24%
2458
11th to 20thNight
23%15%6%9%5%3444423%
2340
21st to endNight
19%14%5%9%6%3445%427%
2574
February1st to 10thNight
22%12%49%5%25%445%27%
2340
11th to 20thNight
23%13%48%5%45%45%5%26%
2184
21st to endNight
24%14%37%5%34435%28%
1776
March1st to 10thNight
18%10%45%5%34445%37%
2004
11th to 20thNight
20%9%47%5%24447%33%
1980
21st to endNight
22%9%45%5%3445%6%33%
2178
April1st to 10thNight
18%9%36%5%2445%6%37%
1962
11th to 20thNight
16%7%35%43346%8%40%
1692
21st to endNight
16%6%36%6%3445%6%40%
1620
May1st to 10thNight
17%7%36%6%45%5%6%6%35%
1620
11th to 20thNight
17%8%37%6%345%5%8%34%
1592
21st to endNight
10%6%25%5%3445%10%44%
1744
June1st to 10thNight
10%5%345%35%5%6%9%46%
1620
11th to 20thNight
9%5%36%5%45%5%6%10%41%
1620
21st to endNight
12%4244346%7%11%44%
1620
July1st to 10thNight
10%6%26%5%45%5%6%9%42%
1620
11th to 20thNight
9%425%5%35%5%6%9%47%
1620
21st to endNight
10%6%35%5%36%7%8%9%39%
1771
August1st to 10thNight
7%5%27%6%46%5%7%9%43%
1611
11th to 20thNight
9%5%27%6%35%5%7%7%44%
1598
21st to endNight
9%5%2443446%10%47%
1836
September1st to 10thNight
12%4245%3445%8%50%
1916
11th to 20thNight
11%42443445%7%53%
1980
21st to endNight
15%5%35%5%3445%6%44%
1980
October1st to 10thNight
13%5%35%4335%47%47%
2092
11th to 20thNight
16%6%35%42445%6%45%
2160
21st to endNight
23%6%25%424346%40%
2376
November1st to 10thNight
13%7%25%5%33445%49%
2342
11th to 20thNight
17%10%36%5%3445%7%36%
2470
21st to endNight
19%10%46%5%35%436%35%
2481
December1st to 10thNight
23%14%6%7%5%34445%25%
2660
11th to 20thNight
18%16%6%7%6%24445%28%
3109
21st to endNight
21%17%6%7%7%44446%21%
4532

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
64%49%15%7%1
1698
11th to 20thDay
67%311%15%4
1620
21st to endDay
65%39%14%7%1
1782
February1st to 10thDay
62%310%17%6%1
1620
11th to 20thDay
60%5%9%17%8%1
1670
21st to endDay
58%39%19%9%1
1480
March1st to 10thDay
50%39%26%10%1
1954
11th to 20thDay
54%5%8%20%12%2
1980
21st to endDay
55%410%19%10%2
2178
April1st to 10thDay
48%5%10%20%13%4
1998
11th to 20thDay
46%411%18%18%4
2230
21st to endDay
48%6%12%20%11%2
2340
May1st to 10thDay
53%5%11%20%10%2
2340
11th to 20thDay
52%6%12%18%11%1
2305
21st to endDay
40%8%16%22%13%1
2531
June1st to 10thDay
41%6%14%23%15%2
2340
11th to 20thDay
41%7%15%21%15%1
2340
21st to endDay
40%8%15%22%14%2
2340
July1st to 10thDay
44%7%13%19%15%2
2275
11th to 20thDay
41%7%12%23%15%2
2271
21st to endDay
42%6%13%24%12%2
2405
August1st to 10thDay
40%9%14%25%11%1
2314
11th to 20thDay
42%8%12%26%11%1
2303
21st to endDay
37%7%13%23%15%4
2502
September1st to 10thDay
37%5%10%22%21%5%
2041
11th to 20thDay
36%6%10%27%19%2
1980
21st to endDay
43%6%8%23%19%1
1980
October1st to 10thDay
38%6%12%24%19%2
1868
11th to 20thDay
44%49%26%16%1
1800
21st to endDay
49%39%23%16%1
1980
November1st to 10thDay
36%5%9%29%17%3
1733
11th to 20thDay
48%48%21%16%3
1710
21st to endDay
50%410%22%14%1
1689
December1st to 10thDay
65%38%18%5%1
1520
11th to 20thDay
61%39%19%7%
2068
21st to endDay
68%5%12%11%4
3124
January1st to 10thNight
63%38%15%9%1
2458
11th to 20thNight
65%410%15%5%1
2340
21st to endNight
60%49%18%7%2
2574
February1st to 10thNight
59%411%18%7%1
2340
11th to 20thNight
60%49%18%9%1
2186
21st to endNight
59%49%16%8%3
1776
March1st to 10thNight
50%38%25%13%1
2004
11th to 20thNight
51%5%10%20%13%1
1980
21st to endNight
52%48%19%13%3
2178
April1st to 10thNight
48%49%21%16%3
1962
11th to 20thNight
41%5%11%20%17%6%
1692
21st to endNight
44%5%10%21%16%2
1620
May1st to 10thNight
48%7%12%19%11%4
1620
11th to 20thNight
48%7%12%18%13%2
1593
21st to endNight
36%6%17%27%13%1
1745
June1st to 10thNight
34%8%11%27%17%3
1620
11th to 20thNight
36%9%14%21%18%2
1620
21st to endNight
33%8%14%25%17%3
1620
July1st to 10thNight
39%7%13%22%17%2
1575
11th to 20thNight
32%7%16%25%17%3
1566
21st to endNight
37%10%12%22%17%1
1672
August1st to 10thNight
36%7%15%26%14%1
1600
11th to 20thNight
37%7%13%25%16%1
1598
21st to endNight
31%7%13%27%18%5%
1836
September1st to 10thNight
33%5%12%21%20%7%
1916
11th to 20thNight
30%6%11%27%23%2
1980
21st to endNight
39%6%11%20%22%2
1980
October1st to 10thNight
36%5%11%26%19%3
2092
11th to 20thNight
40%49%24%20%2
2160
21st to endNight
47%37%24%16%3
2376
November1st to 10thNight
38%411%22%21%5%
2342
11th to 20thNight
48%48%20%17%3
2470
21st to endNight
52%39%22%12%1
2481
December1st to 10thNight
62%49%19%5%1
2660
11th to 20thNight
58%411%19%7%1
3111
21st to endNight
65%410%15%6%
4532

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
31%22%31%12%31
267
11th to 20thDay
33%22%34%9%2
240
21st to endDay
36%25%26%8%3
264
February1st to 10thDay
38%23%27%10%2
240
11th to 20thDay
45%24%27%4
240
21st to endDay
37%21%33%8%1
198
March1st to 10thDay
29%20%28%19%3
394
11th to 20thDay
28%20%32%14%6%1
420
21st to endDay
33%15%29%18%4
462
April1st to 10thDay
27%17%30%17%8%1
420
11th to 20thDay
27%15%28%18%8%3
412
21st to endDay
30%15%29%16%7%2
420
May1st to 10thDay
30%13%27%17%10%3
423
11th to 20thDay
21%11%31%23%11%3
447
21st to endDay
13%8%24%30%19%6%
485
June1st to 10thDay
16%5%25%30%19%6%
450
11th to 20thDay
15%9%22%31%16%7%
450
21st to endDay
13%8%31%25%18%6%
450
July1st to 10thDay
13%419%25%21%17%
445
11th to 20thDay
9%5%22%34%20%10%
444
21st to endDay
18%418%28%22%11%
488
August1st to 10thDay
12%418%33%24%10%
446
11th to 20thDay
13%418%32%22%11%
439
21st to endDay
12%420%27%25%12%
495
September1st to 10thDay
17%417%28%22%12%
450
11th to 20thDay
12%316%29%28%13%
450
21st to endDay
23%9%22%23%19%4
450
October1st to 10thDay
15%8%26%27%18%6%
450
11th to 20thDay
22%12%28%23%12%2
450
21st to endDay
28%13%28%21%9%1
495
November1st to 10thDay
18%15%34%21%8%4
331
11th to 20thDay
30%16%26%20%7%1
270
21st to endDay
22%19%36%19%3
259
December1st to 10thDay
30%18%34%16%21
180
11th to 20thDay
30%19%31%17%3
231
21st to endDay
38%15%28%14%5%
297
January1st to 10thNight
28%18%29%21%4
760
11th to 20thNight
33%15%26%22%4
720
21st to endNight
26%17%33%21%3
792
February1st to 10thNight
28%14%29%27%2
720
11th to 20thNight
33%18%29%19%1
703
21st to endNight
31%17%31%19%2
592
March1st to 10thNight
26%14%32%24%4
720
11th to 20thNight
27%16%28%21%7%1
720
21st to endNight
27%15%28%23%6%1
792
April1st to 10thNight
25%15%32%21%7%
720
11th to 20thNight
20%12%33%24%11%1
628
21st to endNight
19%8%35%31%7%1
540
May1st to 10thNight
20%10%29%27%13%1
540
11th to 20thNight
19%7%28%30%15%1
531
21st to endNight
12%421%32%27%5%
584
June1st to 10thNight
12%223%39%23%1
540
11th to 20thNight
11%420%36%25%3
540
21st to endNight
13%419%37%26%2
540
July1st to 10thNight
11%313%37%31%5%
525
11th to 20thNight
10%414%34%33%6%
522
21st to endNight
13%313%36%30%5%
591
August1st to 10thNight
10%29%41%36%3
537
11th to 20thNight
10%313%36%32%6%
534
21st to endNight
12%411%34%32%7%
648
September1st to 10thNight
13%314%34%29%7%
720
11th to 20thNight
12%314%32%34%5%
720
21st to endNight
18%5%18%34%21%4
720
October1st to 10thNight
16%6%20%32%23%3
720
11th to 20thNight
19%8%27%30%15%1
720
21st to endNight
27%10%21%30%11%1
792
November1st to 10thNight
17%9%26%33%14%1
740
11th to 20thNight
24%13%26%26%11%1
760
21st to endNight
25%11%26%29%7%1
760
December1st to 10thNight
33%13%26%23%5%
760
11th to 20thNight
24%15%31%24%6%
760
21st to endNight
29%13%29%27%3
836
Page generated at 2024-01-07 10:06:51. Version ac07

Copyright 2024 Attilla Danko


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