American Horse Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the American Horse Lake 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
43%
24238
29%
74274
17%
24181
55%
24181
39%
39948

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
37%
950
32%
2458
11%
946
51%
946
43%
1386
January11th to 20thNight
37%
900
32%
2340
13%
900
49%
900
42%
1311
January21st to endNight
37%
990
37%
2574
13%
990
52%
990
46%
1419
February1st to 10thNight
28%
772
27%
2212
10%
772
41%
772
32%
1316
February11th to 20thNight
29%
703
27%
2098
10%
700
42%
700
32%
1201
February21st to endNight
26%
592
32%
1776
11%
592
42%
592
31%
1017
March1st to 10thNight
33%
637
28%
2077
13%
637
48%
637
33%
1130
March11th to 20thNight
31%
540
27%
1980
15%
540
47%
540
28%
1060
March21st to endNight
25%
594
24%
2178
11%
594
43%
594
27%
1161
April1st to 10thNight
27%
540
27%
1980
13%
540
49%
540
35%
947
April11th to 20thNight
23%
533
25%
1739
10%
533
43%
533
28%
986
April21st to endNight
30%
540
28%
1620
13%
540
50%
540
33%
923
May1st to 10thNight
29%
540
25%
1620
13%
540
48%
540
33%
957
May11th to 20thNight
41%
531
21%
1594
18%
531
51%
531
34%
929
May21st to endNight
47%
582
24%
1745
18%
582
58%
582
39%
962
June1st to 10thNight
57%
540
24%
1620
18%
540
66%
540
44%
841
June11th to 20thNight
50%
540
25%
1620
16%
540
61%
540
48%
821
June21st to endNight
60%
540
28%
1620
23%
540
68%
540
55%
772
July1st to 10thNight
72%
525
21%
1575
21%
525
75%
525
45%
828
July11th to 20thNight
76%
522
28%
1566
28%
522
80%
522
52%
761
July21st to endNight
81%
591
31%
1673
35%
558
82%
558
51%
833
August1st to 10thNight
74%
537
29%
1601
30%
534
79%
534
50%
799
August11th to 20thNight
69%
534
30%
1605
32%
534
74%
534
41%
888
August21st to endNight
76%
594
28%
1980
31%
594
79%
594
47%
950
September1st to 10thNight
64%
540
27%
1976
28%
540
69%
540
39%
951
September11th to 20thNight
56%
540
28%
1980
26%
540
64%
540
31%
1088
September21st to endNight
57%
540
34%
1980
28%
540
67%
540
41%
935
October1st to 10thNight
51%
540
34%
1980
28%
540
62%
540
39%
951
October11th to 20thNight
41%
684
36%
2124
17%
684
56%
684
44%
1070
October21st to endNight
41%
792
34%
2376
16%
792
54%
792
43%
1229
November1st to 10thNight
43%
897
34%
2377
13%
897
57%
897
50%
1267
November11th to 20thNight
38%
950
33%
2470
13%
950
50%
950
48%
1339
November21st to endNight
39%
950
32%
2470
14%
950
50%
950
40%
1429
December1st to 10thNight
37%
950
33%
2470
13%
950
50%
950
43%
1409
December11th to 20thNight
30%
949
32%
2863
11%
948
44%
948
32%
1659
December21st to endNight
32%
1039
22%
4357
12%
1026
48%
1026
24%
2423

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%5%2442445%7%55%
74877
Night
8%424324447%58%
74829
TransparencyDay
30%5%10%26%23%7%
74602
Night
27%49%25%26%9%
74624
SeeingDay
11%8%28%31%18%4
14220
Night
10%8%34%35%12%1
24248

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
7%424324346%60%
1698
11th to 20thDay
9%6%24333446%56%
1620
21st to endDay
7%6%34323447%58%
1782
February1st to 10thDay
10%9%45%42323454%
1764
11th to 20thDay
9%6%35%5%2435%5%54%
1749
21st to endDay
10%7%3433443455%
1480
March1st to 10thDay
10%7%25%5%25%446%50%
1881
11th to 20thDay
13%8%24324345%52%
1980
21st to endDay
9%7%25%6%2445%7%48%
2178
April1st to 10thDay
8%32443445%8%55%
1980
11th to 20thDay
11%6%25%5%3445%6%48%
2167
21st to endDay
13%5%2443345%7%52%
2340
May1st to 10thDay
12%6%35%5%245%5%5%47%
2340
11th to 20thDay
12%5%2443445%7%51%
2302
21st to endDay
11%425%6%35%6%5%8%43%
2531
June1st to 10thDay
6%3245%35%5%6%9%53%
2340
11th to 20thDay
6%4234245%5%7%58%
2340
21st to endDay
5%3134245%5%8%61%
2340
July1st to 10thDay
7%3245%35%5%7%9%49%
2340
11th to 20thDay
4313325%45%9%60%
2340
21st to endDay
44245%2447%9%56%
2546
August1st to 10thDay
43145%25%5%6%10%56%
2328
11th to 20thDay
7%5%24435%5%6%9%49%
2292
21st to endDay
32234345%5%9%59%
2376
September1st to 10thDay
9%5%24323346%59%
1981
11th to 20thDay
9%5%25%4345%5%6%52%
1980
21st to endDay
7%42342445%6%59%
1980
October1st to 10thDay
9%424424335%61%
1980
11th to 20thDay
10%31322223468%
1818
21st to endDay
11%423423235%61%
1980
November1st to 10thDay
7%313323446%64%
1698
11th to 20thDay
6%423222335%67%
1710
21st to endDay
10%423323346%59%
1710
December1st to 10thDay
6%6%25%5%23347%56%
1710
11th to 20thDay
9%6%26%423345%56%
2161
21st to endDay
8%8%47%6%34446%44%
3135
January1st to 10thNight
6%424325%45%6%60%
2458
11th to 20thNight
7%6%23323346%60%
2340
21st to endNight
7%424323246%63%
2574
February1st to 10thNight
12%7%35%423335%54%
2212
11th to 20thNight
11%6%24423436%54%
2098
21st to endNight
9%6%35%33445%6%54%
1776
March1st to 10thNight
5%425%5%35%5%5%7%54%
2077
11th to 20thNight
15%6%23323335%56%
1980
21st to endNight
8%5%35%43445%7%52%
2178
April1st to 10thNight
8%4133245%47%60%
1980
11th to 20thNight
12%5%25%42345%6%52%
1739
21st to endNight
13%413424346%55%
1620
May1st to 10thNight
11%5%34425%5%47%52%
1620
11th to 20thNight
9%42343446%9%50%
1593
21st to endNight
7%42343346%10%54%
1745
June1st to 10thNight
432342447%11%57%
1620
11th to 20thNight
5%32232445%9%60%
1620
21st to endNight
5%21322336%9%66%
1620
July1st to 10thNight
4224435%47%11%55%
1620
11th to 20thNight
42134245%5%12%60%
1620
21st to endNight
321242446%11%61%
1772
August1st to 10thNight
2213425%7%6%11%58%
1611
11th to 20thNight
6%324435%46%7%55%
1605
21st to endNight
32133345%6%9%61%
1980
September1st to 10thNight
7%5%2432345%6%61%
1976
11th to 20thNight
11%5%24434447%52%
1980
21st to endNight
6%41432345%7%60%
1980
October1st to 10thNight
7%32432345%7%60%
1980
11th to 20thNight
8%42332233467%
2124
21st to endNight
9%42332233465%
2376
November1st to 10thNight
7%413223336%66%
2377
11th to 20thNight
5%424323235%66%
2470
21st to endNight
10%5%23323346%60%
2470
December1st to 10thNight
9%414323345%61%
2470
11th to 20thNight
7%6%35%5%24335%56%
3036
21st to endNight
11%7%24434446%51%
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
26%410%30%23%7%
1699
11th to 20thDay
31%39%21%31%6%
1620
21st to endDay
28%37%29%26%7%
1782
February1st to 10thDay
36%28%25%23%6%
1764
11th to 20thDay
34%47%24%24%8%
1759
21st to endDay
35%35%22%25%10%
1480
March1st to 10thDay
35%5%8%22%18%12%
1881
11th to 20thDay
36%49%23%19%9%
1980
21st to endDay
36%5%11%24%18%6%
2178
April1st to 10thDay
28%5%11%27%21%9%
1980
11th to 20thDay
36%49%23%19%9%
2167
21st to endDay
34%411%26%22%3
2340
May1st to 10thDay
38%5%10%19%21%7%
2340
11th to 20thDay
33%6%12%30%17%3
2306
21st to endDay
38%6%13%26%14%3
2531
June1st to 10thDay
27%7%16%29%15%6%
2340
11th to 20thDay
24%5%13%28%23%7%
2340
21st to endDay
20%6%14%26%27%7%
2340
July1st to 10thDay
29%7%15%27%19%2
2276
11th to 20thDay
20%6%11%30%27%7%
2271
21st to endDay
24%5%13%32%23%3
2405
August1st to 10thDay
23%5%14%31%20%7%
2314
11th to 20thDay
30%6%14%27%20%4
2292
21st to endDay
22%6%12%29%23%8%
2376
September1st to 10thDay
28%48%24%24%12%
1981
11th to 20thDay
33%5%8%23%25%6%
1980
21st to endDay
25%47%25%30%8%
1980
October1st to 10thDay
27%410%23%27%9%
1980
11th to 20thDay
23%27%20%32%15%
1818
21st to endDay
28%37%26%24%12%
1980
November1st to 10thDay
22%37%25%31%12%
1698
11th to 20thDay
22%26%29%29%11%
1710
21st to endDay
29%35%26%26%11%
1710
December1st to 10thDay
29%49%29%24%5%
1710
11th to 20thDay
32%39%19%30%7%
2159
21st to endDay
40%47%22%22%5%
3135
January1st to 10thNight
26%39%27%29%7%
2458
11th to 20thNight
26%37%26%30%8%
2340
21st to endNight
25%26%26%29%12%
2574
February1st to 10thNight
35%37%22%25%8%
2212
11th to 20thNight
32%47%24%22%10%
2098
21st to endNight
32%45%20%25%14%
1776
March1st to 10thNight
29%48%20%24%15%
2077
11th to 20thNight
33%38%25%21%10%
1980
21st to endNight
32%412%26%20%6%
2178
April1st to 10thNight
24%411%23%26%12%
1980
11th to 20thNight
33%49%26%19%10%
1739
21st to endNight
31%5%11%26%22%5%
1620
May1st to 10thNight
33%5%12%20%23%7%
1620
11th to 20thNight
31%6%14%25%19%5%
1594
21st to endNight
27%6%17%30%18%3
1746
June1st to 10thNight
21%6%17%33%18%5%
1620
11th to 20thNight
21%5%15%29%24%6%
1620
21st to endNight
16%5%12%31%25%11%
1620
July1st to 10thNight
22%7%18%29%21%3
1575
11th to 20thNight
17%5%11%27%30%10%
1566
21st to endNight
19%5%12%31%29%4
1673
August1st to 10thNight
18%7%14%31%23%7%
1601
11th to 20thNight
26%7%12%25%24%7%
1605
21st to endNight
19%6%13%27%26%8%
1980
September1st to 10thNight
24%5%9%25%25%12%
1976
11th to 20thNight
33%5%9%19%25%9%
1980
21st to endNight
23%47%25%30%11%
1980
October1st to 10thNight
24%412%22%26%12%
1980
11th to 20thNight
24%2420%31%18%
2124
21st to endNight
25%26%25%28%13%
2376
November1st to 10thNight
22%38%23%30%14%
2377
11th to 20thNight
22%35%26%31%12%
2470
21st to endNight
28%45%22%28%13%
2470
December1st to 10thNight
26%39%27%27%8%
2470
11th to 20thNight
32%25%21%31%8%
3037
21st to endNight
34%5%7%22%25%8%
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
10%14%40%27%7%1
267
11th to 20thDay
17%17%35%25%6%
240
21st to endDay
10%16%48%20%6%
264
February1st to 10thDay
14%14%41%28%4
240
11th to 20thDay
11%21%46%17%4
240
21st to endDay
17%19%43%17%4
198
March1st to 10thDay
13%20%40%22%5%
240
11th to 20thDay
21%16%36%20%5%1
240
21st to endDay
17%15%43%19%5%
264
April1st to 10thDay
15%14%40%21%10%
240
11th to 20thDay
14%18%44%20%4
445
21st to endDay
16%15%38%23%6%2
600
May1st to 10thDay
13%9%43%26%8%1
603
11th to 20thDay
17%7%31%30%14%2
625
21st to endDay
13%7%31%29%16%4
679
June1st to 10thDay
8%322%39%23%5%
630
11th to 20thDay
7%231%40%16%3
630
21st to endDay
6%225%40%22%5%
630
July1st to 10thDay
6%111%34%35%11%
621
11th to 20thDay
4111%40%36%8%
618
21st to endDay
5%15%39%38%12%
684
August1st to 10thDay
5%111%46%33%5%
626
11th to 20thDay
9%111%38%35%7%
606
21st to endDay
5%110%37%36%12%
495
September1st to 10thDay
7%6%41%35%10%
271
11th to 20thDay
7%314%41%29%6%
270
21st to endDay
12%320%32%23%9%
270
October1st to 10thDay
9%6%30%30%20%5%
270
11th to 20thDay
10%10%36%31%11%1
270
21st to endDay
20%9%33%24%11%2
297
November1st to 10thDay
10%8%35%34%10%3
270
11th to 20thDay
14%10%38%24%12%2
270
21st to endDay
17%13%37%23%10%1
270
December1st to 10thDay
8%10%46%23%11%2
270
11th to 20thDay
16%11%39%24%9%
270
21st to endDay
15%18%39%22%5%
297
January1st to 10thNight
8%13%39%34%6%
950
11th to 20thNight
12%12%36%34%6%
900
21st to endNight
10%11%40%32%7%
990
February1st to 10thNight
17%10%41%28%5%
772
11th to 20thNight
14%14%41%26%5%
704
21st to endNight
15%14%44%24%4
592
March1st to 10thNight
8%15%42%30%5%
637
11th to 20thNight
17%12%37%27%6%
540
21st to endNight
11%16%45%24%4
594
April1st to 10thNight
9%14%46%24%7%
540
11th to 20thNight
14%16%43%24%3
533
21st to endNight
16%11%41%25%7%
540
May1st to 10thNight
13%11%44%27%41
540
11th to 20thNight
11%7%35%33%13%
531
21st to endNight
8%5%36%36%14%2
584
June1st to 10thNight
6%326%44%19%2
540
11th to 20thNight
6%435%43%11%
540
21st to endNight
4229%47%17%1
540
July1st to 10thNight
4114%46%31%3
525
11th to 20thNight
413%51%29%2
522
21st to endNight
417%55%30%3
591
August1st to 10thNight
315%50%29%2
537
11th to 20thNight
7%114%49%27%2
534
21st to endNight
413%43%36%3
594
September1st to 10thNight
7%220%44%25%3
540
11th to 20thNight
14%121%36%26%2
540
21st to endNight
8%326%41%18%3
540
October1st to 10thNight
9%430%37%19%1
540
11th to 20thNight
11%7%38%35%9%
684
21st to endNight
12%9%36%30%13%1
792
November1st to 10thNight
10%7%37%34%10%1
897
11th to 20thNight
7%10%41%33%8%1
950
21st to endNight
13%12%33%31%10%
950
December1st to 10thNight
12%9%38%31%9%1
950
11th to 20thNight
13%11%40%29%7%
950
21st to endNight
13%12%38%31%6%
1045
Page generated at 2024-01-07 09:06:50. Version ac07

Copyright 2024 Attilla Danko


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