Beaver Dam
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Beaver Dam clear sky chart from 2005-11-06 to 2024-01-13.

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
36%
24721
16%
74654
10%
24668
43%
24668
22%
50779

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
23%
950
13%
2648
6%
946
30%
946
17%
1937
January11th to 20thNight
20%
911
11%
2549
4%
911
27%
911
14%
1998
January21st to endNight
21%
990
11%
2736
4%
990
27%
990
15%
2113
February1st to 10thNight
23%
900
12%
2340
3%
900
29%
900
19%
1735
February11th to 20thNight
27%
743
19%
2142
7%
743
36%
743
20%
1482
February21st to endNight
21%
592
16%
1776
4%
592
32%
592
17%
1262
March1st to 10thNight
32%
720
15%
2160
8%
720
38%
720
20%
1485
March11th to 20thNight
36%
661
20%
2101
13%
661
44%
661
25%
1307
March21st to endNight
34%
594
17%
1987
14%
594
41%
594
17%
1394
April1st to 10thNight
27%
540
13%
1800
9%
540
35%
540
17%
1236
April11th to 20thNight
32%
533
19%
1775
14%
533
42%
533
19%
1188
April21st to endNight
34%
540
16%
1702
9%
540
42%
540
22%
1142
May1st to 10thNight
33%
540
15%
1562
9%
540
38%
540
22%
1080
May11th to 20thNight
36%
531
18%
1416
8%
531
44%
531
25%
986
May21st to endNight
47%
583
15%
1552
8%
582
52%
582
29%
1032
June1st to 10thNight
53%
540
16%
1440
9%
540
57%
540
35%
897
June11th to 20thNight
48%
540
18%
1440
9%
540
54%
540
35%
903
June21st to endNight
54%
540
17%
1440
11%
540
58%
540
37%
890
July1st to 10thNight
68%
525
18%
1400
11%
525
70%
525
43%
815
July11th to 20thNight
66%
522
21%
1392
15%
522
68%
522
41%
816
July21st to endNight
68%
591
21%
1487
15%
558
71%
558
42%
879
August1st to 10thNight
67%
537
21%
1423
16%
534
68%
534
39%
865
August11th to 20thNight
66%
534
21%
1720
20%
534
70%
534
35%
983
August21st to endNight
62%
594
22%
1980
23%
594
66%
594
34%
1112
September1st to 10thNight
57%
540
23%
1800
23%
540
63%
540
32%
1023
September11th to 20thNight
55%
600
29%
1860
25%
600
60%
600
33%
1090
September21st to endNight
45%
720
23%
1980
13%
720
52%
720
32%
1227
October1st to 10thNight
45%
720
23%
2088
15%
720
51%
720
31%
1290
October11th to 20thNight
31%
720
18%
2162
9%
720
41%
720
22%
1451
October21st to endNight
29%
792
15%
2574
10%
792
37%
792
18%
1783
November1st to 10thNight
32%
740
24%
2406
16%
740
44%
740
24%
1510
November11th to 20thNight
23%
760
16%
2470
8%
760
33%
760
16%
1744
November21st to endNight
26%
942
16%
2652
8%
942
34%
942
19%
1882
December1st to 10thNight
19%
950
12%
2660
3%
950
27%
950
16%
1961
December11th to 20thNight
18%
949
11%
3210
3%
948
25%
948
11%
2454
December21st to endNight
16%
1037
6%
4824
2%
1026
23%
1026
7%
3827

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
13%9%47%6%35%5%6%8%37%
74785
Night
14%9%46%5%3445%7%38%
74966
TransparencyDay
45%7%13%22%12%1
74486
Night
45%6%12%22%13%1
74786
SeeingDay
16%9%28%27%15%5%
14737
Night
17%9%31%31%12%1
24734

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
11%10%5%9%7%46%6%6%7%29%
1517
11th to 20thDay
12%15%7%13%8%45%45%7%21%
1456
21st to endDay
12%14%8%12%7%445%5%7%21%
1616
February1st to 10thDay
12%12%6%9%5%46%5%5%6%31%
1620
11th to 20thDay
13%11%46%5%35%5%5%7%36%
1704
21st to endDay
11%13%5%9%7%35%6%5%6%29%
1480
March1st to 10thDay
13%10%47%6%35%5%6%7%35%
1800
11th to 20thDay
13%7%46%6%35%5%5%6%40%
1875
21st to endDay
19%9%48%6%35%45%7%31%
2368
April1st to 10thDay
17%12%5%6%5%3445%7%30%
2160
11th to 20thDay
17%10%36%6%3446%6%34%
2134
21st to endDay
19%9%36%6%35%45%8%32%
2256
May1st to 10thDay
16%8%37%6%35%5%7%8%33%
2396
11th to 20thDay
18%7%26%5%3446%7%38%
2479
21st to endDay
13%7%36%5%36%46%8%39%
2725
June1st to 10thDay
9%5%36%5%35%5%6%8%45%
2520
11th to 20thDay
12%5%25%6%35%5%6%9%43%
2520
21st to endDay
10%6%25%435%6%7%10%43%
2520
July1st to 10thDay
7%425%425%5%8%10%47%
2520
11th to 20thDay
7%5%245%45%6%7%9%46%
2520
21st to endDay
7%424435%5%6%11%48%
2743
August1st to 10thDay
7%4246%35%7%7%10%44%
2507
11th to 20thDay
11%6%26%5%4445%8%45%
2176
21st to endDay
11%5%25%5%345%5%9%46%
2376
September1st to 10thDay
13%6%25%435%46%7%44%
2160
11th to 20thDay
13%5%25%43435%7%49%
2081
21st to endDay
12%7%36%5%345%6%7%42%
1980
October1st to 10thDay
14%8%26%434447%44%
1869
11th to 20thDay
21%9%36%6%4446%7%31%
1797
21st to endDay
18%9%37%5%34445%36%
1782
November1st to 10thDay
12%8%36%5%3445%7%43%
1672
11th to 20thDay
13%11%5%9%8%4445%7%31%
1710
21st to endDay
18%10%48%6%2445%6%34%
1525
December1st to 10thDay
12%14%5%9%8%46%447%27%
1520
11th to 20thDay
13%14%5%8%7%35%45%7%27%
1918
21st to endDay
18%20%9%14%7%4434413%
2783
January1st to 10thNight
13%12%6%8%7%35%445%34%
2648
11th to 20thNight
14%14%7%11%6%445%45%27%
2549
21st to endNight
12%13%7%11%7%45%45%6%26%
2736
February1st to 10thNight
10%15%6%9%6%4445%6%32%
2340
11th to 20thNight
12%9%48%6%35%45%5%39%
2141
21st to endNight
17%12%5%6%5%35%5%45%34%
1776
March1st to 10thNight
16%9%36%436%45%7%36%
2160
11th to 20thNight
13%7%35%4345%6%8%42%
2101
21st to endNight
18%9%46%6%35%5%5%7%33%
1987
April1st to 10thNight
18%10%46%435%5%5%5%36%
1800
11th to 20thNight
21%8%35%44445%6%37%
1775
21st to endNight
18%8%36%5%3445%7%38%
1702
May1st to 10thNight
17%8%46%6%346%6%9%32%
1562
11th to 20thNight
16%6%25%6%35%5%6%7%38%
1416
21st to endNight
11%5%26%5%346%6%9%41%
1551
June1st to 10thNight
9%5%24435%5%7%8%48%
1440
11th to 20thNight
11%5%35%5%344410%48%
1440
21st to endNight
9%4245%3446%9%50%
1440
July1st to 10thNight
6%4243345%6%9%55%
1440
11th to 20thNight
6%424426%5%6%8%55%
1440
21st to endNight
6%3145%35%6%8%9%52%
1575
August1st to 10thNight
6%435%4435%7%9%49%
1432
11th to 20thNight
9%425%3345%5%8%51%
1720
21st to endNight
9%42443445%8%52%
1980
September1st to 10thNight
10%5%244245%5%6%54%
1800
11th to 20thNight
13%42443445%6%51%
1860
21st to endNight
11%6%35%42445%7%49%
1980
October1st to 10thNight
13%6%36%5%2245%6%48%
2088
11th to 20thNight
18%8%36%5%2445%6%39%
2162
21st to endNight
20%10%36%5%3445%6%34%
2574
November1st to 10thNight
13%7%26%43445%6%45%
2406
11th to 20thNight
14%10%5%7%7%4445%7%32%
2470
21st to endNight
16%10%36%5%3445%6%37%
2652
December1st to 10thNight
13%12%49%7%35%5%47%30%
2660
11th to 20thNight
14%14%6%9%7%45%45%428%
3279
21st to endNight
21%17%6%9%6%3445%5%20%
4884

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
52%8%14%16%9%
1518
11th to 20thDay
63%6%10%14%8%
1456
21st to endDay
62%5%13%13%7%
1616
February1st to 10thDay
55%5%13%18%8%1
1620
11th to 20thDay
48%6%12%22%10%2
1714
21st to endDay
55%6%10%17%10%2
1480
March1st to 10thDay
49%7%13%21%9%2
1800
11th to 20thDay
43%7%11%22%14%1
1875
21st to endDay
54%7%11%20%8%1
2368
April1st to 10thDay
53%7%12%18%10%
2160
11th to 20thDay
49%7%10%20%12%2
2134
21st to endDay
50%8%12%19%10%1
2256
May1st to 10thDay
47%7%15%22%8%1
2396
11th to 20thDay
46%6%13%22%12%1
2483
21st to endDay
43%7%12%23%13%2
2725
June1st to 10thDay
35%8%13%27%15%2
2520
11th to 20thDay
38%6%13%24%17%1
2520
21st to endDay
35%10%16%24%14%1
2520
July1st to 10thDay
30%8%15%31%14%2
2451
11th to 20thDay
31%9%16%26%16%2
2445
21st to endDay
28%9%17%27%15%3
2591
August1st to 10thDay
31%10%17%28%12%2
2492
11th to 20thDay
37%6%15%29%12%1
2176
21st to endDay
35%6%14%25%18%2
2376
September1st to 10thDay
38%8%12%24%17%1
2160
11th to 20thDay
34%6%14%31%14%1
2081
21st to endDay
40%6%12%30%12%
1980
October1st to 10thDay
41%6%9%28%15%1
1869
11th to 20thDay
51%6%12%20%10%1
1797
21st to endDay
50%5%13%20%12%
1782
November1st to 10thDay
41%5%16%22%14%2
1672
11th to 20thDay
53%6%13%20%8%1
1710
21st to endDay
52%5%14%22%7%
1525
December1st to 10thDay
58%5%14%15%7%1
1520
11th to 20thDay
55%6%15%16%6%2
1915
21st to endDay
74%5%8%8%5%
2783
January1st to 10thNight
53%5%11%19%11%1
2648
11th to 20thNight
60%6%11%14%8%
2549
21st to endNight
59%5%11%15%9%1
2736
February1st to 10thNight
53%5%10%20%11%2
2340
11th to 20thNight
48%5%12%20%14%1
2142
21st to endNight
51%6%11%19%12%2
1776
March1st to 10thNight
47%6%14%20%11%2
2160
11th to 20thNight
39%6%14%24%15%2
2101
21st to endNight
51%6%10%21%11%2
1987
April1st to 10thNight
48%7%9%19%15%1
1800
11th to 20thNight
49%48%19%17%3
1775
21st to endNight
44%7%13%20%14%2
1702
May1st to 10thNight
47%7%14%21%12%1
1562
11th to 20thNight
43%8%12%23%12%2
1417
21st to endNight
38%9%13%24%14%2
1552
June1st to 10thNight
32%8%14%27%19%
1440
11th to 20thNight
33%7%10%28%19%2
1440
21st to endNight
31%8%16%25%18%2
1440
July1st to 10thNight
25%8%15%30%19%3
1400
11th to 20thNight
27%7%13%30%21%3
1392
21st to endNight
25%9%16%29%16%5%
1487
August1st to 10thNight
29%8%17%27%16%3
1423
11th to 20thNight
29%8%15%31%17%1
1720
21st to endNight
30%7%13%28%19%3
1980
September1st to 10thNight
30%8%11%26%23%2
1800
11th to 20thNight
33%6%10%33%17%1
1860
21st to endNight
35%6%11%30%16%1
1980
October1st to 10thNight
36%5%9%30%18%1
2088
11th to 20thNight
45%6%12%20%16%1
2162
21st to endNight
50%5%11%22%11%1
2574
November1st to 10thNight
40%6%10%26%15%2
2406
11th to 20thNight
51%6%13%18%11%1
2470
21st to endNight
49%6%14%22%9%1
2652
December1st to 10thNight
54%6%12%19%8%1
2660
11th to 20thNight
59%6%10%17%7%1
3281
21st to endNight
67%6%9%13%5%
4884

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
14%11%34%31%9%1
270
11th to 20thDay
17%13%32%27%9%1
246
21st to endDay
20%10%34%28%6%2
264
February1st to 10thDay
14%15%44%22%5%
240
11th to 20thDay
19%19%31%23%7%
240
21st to endDay
18%17%40%23%2
198
March1st to 10thDay
15%16%42%22%32
240
11th to 20thDay
20%13%30%25%9%4
240
21st to endDay
25%11%31%23%8%2
454
April1st to 10thDay
25%12%32%26%5%
420
11th to 20thDay
25%15%28%19%11%2
412
21st to endDay
21%12%29%24%12%2
420
May1st to 10thDay
20%10%35%23%10%2
479
11th to 20thDay
22%8%28%26%13%3
625
21st to endDay
17%9%26%25%15%7%
679
June1st to 10thDay
9%7%28%34%18%4
630
11th to 20thDay
15%6%29%29%16%5%
630
21st to endDay
13%7%26%32%18%4
630
July1st to 10thDay
8%317%33%26%13%
621
11th to 20thDay
9%5%25%34%21%7%
618
21st to endDay
7%326%35%23%7%
684
August1st to 10thDay
8%319%34%25%11%
626
11th to 20thDay
14%5%13%27%26%15%
473
21st to endDay
12%6%19%28%23%11%
495
September1st to 10thDay
16%6%21%27%22%8%
450
11th to 20thDay
12%5%20%31%22%10%
450
21st to endDay
16%11%26%23%19%6%
450
October1st to 10thDay
19%11%21%26%18%5%
339
11th to 20thDay
25%16%30%19%10%1
270
21st to endDay
24%14%35%20%5%2
297
November1st to 10thDay
13%18%37%21%10%1
270
11th to 20thDay
15%18%37%19%10%
270
21st to endDay
23%13%38%19%7%
270
December1st to 10thDay
19%16%42%16%7%
270
11th to 20thDay
21%13%34%20%11%1
270
21st to endDay
26%15%38%17%4
297
January1st to 10thNight
17%15%35%25%7%1
950
11th to 20thNight
20%12%34%27%6%1
911
21st to endNight
19%10%36%28%5%1
990
February1st to 10thNight
17%12%37%27%6%1
900
11th to 20thNight
17%14%35%28%6%
746
21st to endNight
22%15%36%22%41
592
March1st to 10thNight
19%9%33%30%8%1
720
11th to 20thNight
17%10%34%30%8%1
661
21st to endNight
21%8%29%31%10%1
594
April1st to 10thNight
22%11%36%25%5%
540
11th to 20thNight
23%10%31%28%7%
533
21st to endNight
22%9%31%29%10%1
540
May1st to 10thNight
18%9%34%30%7%
540
11th to 20thNight
18%7%33%30%11%
531
21st to endNight
12%5%28%36%17%1
584
June1st to 10thNight
10%426%44%15%1
540
11th to 20thNight
13%429%39%14%1
540
21st to endNight
10%425%44%16%
540
July1st to 10thNight
7%117%39%33%3
525
11th to 20thNight
6%419%47%22%2
522
21st to endNight
7%117%50%24%2
591
August1st to 10thNight
9%214%48%25%2
537
11th to 20thNight
10%215%40%29%5%
534
21st to endNight
11%119%43%24%3
594
September1st to 10thNight
10%423%38%21%5%
540
11th to 20thNight
13%423%34%23%4
600
21st to endNight
12%8%29%28%21%2
720
October1st to 10thNight
15%6%28%33%17%1
720
11th to 20thNight
21%11%32%27%9%
720
21st to endNight
24%9%31%28%7%1
792
November1st to 10thNight
17%10%36%26%10%1
740
11th to 20thNight
21%14%37%22%6%1
760
21st to endNight
21%13%34%24%7%
942
December1st to 10thNight
21%13%40%21%6%
950
11th to 20thNight
23%13%35%23%6%1
950
21st to endNight
28%12%34%22%4
1045
Page generated at 2024-01-10 00:25:00. Version ac07

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