Bearbower Sand Prairie Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bearbower Sand Prairie Area 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%
24682
18%
74678
10%
24623
43%
24623
24%
49479

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
26%
950
14%
2648
5%
946
33%
946
21%
1847
January11th to 20thNight
24%
915
11%
2508
5%
915
28%
915
15%
1944
January21st to endNight
22%
990
13%
2574
4%
990
28%
990
16%
1961
February1st to 10thNight
22%
900
12%
2340
3%
900
28%
900
19%
1738
February11th to 20thNight
27%
872
17%
2268
6%
869
34%
869
24%
1567
February21st to endNight
25%
592
18%
1776
5%
592
35%
592
19%
1224
March1st to 10thNight
25%
648
17%
2088
9%
648
33%
648
21%
1366
March11th to 20thNight
32%
540
19%
1980
13%
540
42%
540
20%
1245
March21st to endNight
23%
594
11%
2116
4%
594
32%
594
13%
1548
April1st to 10thNight
24%
540
17%
1800
10%
540
36%
540
20%
1189
April11th to 20thNight
28%
533
18%
1775
12%
533
40%
533
19%
1178
April21st to endNight
31%
540
18%
1763
12%
540
42%
540
22%
1155
May1st to 10thNight
34%
540
16%
1535
9%
540
41%
540
24%
1056
May11th to 20thNight
38%
531
18%
1417
10%
531
44%
531
27%
971
May21st to endNight
43%
584
16%
1551
7%
582
49%
582
29%
1037
June1st to 10thNight
54%
540
17%
1440
9%
540
59%
540
37%
885
June11th to 20thNight
51%
540
18%
1440
9%
540
54%
540
35%
892
June21st to endNight
52%
540
19%
1440
10%
540
57%
540
37%
889
July1st to 10thNight
73%
525
18%
1400
11%
525
74%
525
43%
807
July11th to 20thNight
67%
522
23%
1392
14%
522
70%
522
48%
767
July21st to endNight
65%
591
24%
1543
18%
558
68%
558
42%
892
August1st to 10thNight
70%
537
21%
1601
22%
534
72%
534
40%
902
August11th to 20thNight
66%
534
25%
1618
25%
534
71%
534
36%
926
August21st to endNight
64%
594
23%
1980
26%
594
68%
594
35%
1074
September1st to 10thNight
56%
540
23%
1800
21%
540
62%
540
31%
1025
September11th to 20thNight
59%
540
30%
1800
28%
540
64%
540
34%
1001
September21st to endNight
48%
657
25%
2038
16%
657
58%
657
36%
1136
October1st to 10thNight
44%
720
22%
2160
15%
720
50%
720
33%
1282
October11th to 20thNight
32%
720
22%
2160
12%
720
42%
720
26%
1374
October21st to endNight
31%
792
19%
2399
10%
792
39%
792
22%
1593
November1st to 10thNight
33%
740
25%
2406
15%
740
46%
740
29%
1398
November11th to 20thNight
25%
893
19%
2603
8%
893
34%
893
22%
1737
November21st to endNight
27%
950
18%
2660
8%
950
36%
950
23%
1801
December1st to 10thNight
22%
950
12%
2660
4%
950
30%
950
19%
1915
December11th to 20thNight
26%
949
14%
3166
5%
948
32%
948
15%
2242
December21st to endNight
18%
1039
9%
4833
4%
1026
28%
1026
8%
3915

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
14%8%36%6%35%5%5%7%37%
74737
Night
13%8%36%5%3445%7%41%
75029
TransparencyDay
45%6%13%22%12%1
74441
Night
44%5%12%23%14%2
74845
SeeingDay
16%10%30%26%14%4
14697
Night
16%9%32%31%11%1
24690

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%11%6%10%8%6%7%5%46%26%
1517
11th to 20thDay
13%13%6%11%8%46%447%25%
1511
21st to endDay
14%13%7%10%8%46%5%5%7%22%
1782
February1st to 10thDay
12%13%5%8%8%45%5%5%6%29%
1620
11th to 20thDay
13%10%46%6%46%6%46%33%
1578
21st to endDay
15%11%49%7%346%5%6%32%
1480
March1st to 10thDay
15%11%5%8%6%245%5%6%34%
1888
11th to 20thDay
14%8%47%7%44449%34%
1980
21st to endDay
22%11%47%6%35%45%6%27%
2240
April1st to 10thDay
19%11%47%5%345%5%6%31%
2160
11th to 20thDay
16%11%38%6%35%45%7%33%
2134
21st to endDay
23%8%35%5%3445%6%34%
2194
May1st to 10thDay
18%7%37%6%46%5%6%7%30%
2422
11th to 20thDay
19%8%37%5%345%47%36%
2479
21st to endDay
16%6%26%6%35%5%6%8%35%
2725
June1st to 10thDay
12%4245%46%5%6%9%44%
2520
11th to 20thDay
11%5%36%4245%6%8%46%
2520
21st to endDay
12%5%35%6%35%5%6%9%40%
2520
July1st to 10thDay
8%4345%35%5%6%10%47%
2520
11th to 20thDay
7%5%25%5%35%5%7%9%47%
2520
21st to endDay
6%4245%45%6%7%11%47%
2681
August1st to 10thDay
8%5%26%5%35%7%7%9%42%
2328
11th to 20thDay
11%6%25%6%245%6%9%45%
2281
21st to endDay
10%425%5%3445%8%50%
2376
September1st to 10thDay
15%416%43435%8%48%
2160
11th to 20thDay
11%425%5%345%48%51%
2160
21st to endDay
11%5%25%5%35%5%5%8%46%
1898
October1st to 10thDay
16%5%36%5%3345%6%43%
1800
11th to 20thDay
19%8%345%34446%40%
1800
21st to endDay
17%10%36%5%23446%40%
1955
November1st to 10thDay
11%7%35%5%35%45%6%46%
1672
11th to 20thDay
14%10%6%6%6%25%447%35%
1575
21st to endDay
16%10%36%6%34447%38%
1520
December1st to 10thDay
13%12%5%10%6%36%437%31%
1520
11th to 20thDay
14%11%48%7%5%446%7%30%
1918
21st to endDay
22%19%8%12%5%2434416%
2783
January1st to 10thNight
10%10%6%8%6%45%5%46%36%
2648
11th to 20thNight
12%13%6%11%8%35%5%46%26%
2508
21st to endNight
13%12%5%11%7%45%446%29%
2574
February1st to 10thNight
12%12%5%8%8%35%445%33%
2340
11th to 20thNight
12%9%37%6%35%447%39%
2267
21st to endNight
14%10%47%6%45%446%36%
1776
March1st to 10thNight
16%9%37%5%23337%40%
2088
11th to 20thNight
13%8%36%6%4445%7%41%
1980
21st to endNight
19%10%5%7%7%44446%29%
2116
April1st to 10thNight
15%9%46%5%3445%5%41%
1800
11th to 20thNight
16%9%35%5%345%46%39%
1775
21st to endNight
18%7%26%43446%6%39%
1763
May1st to 10thNight
16%7%35%5%35%6%5%7%39%
1535
11th to 20thNight
16%6%36%5%4445%8%39%
1416
21st to endNight
13%7%35%5%35%5%5%7%43%
1551
June1st to 10thNight
8%425%435%5%7%7%49%
1440
11th to 20thNight
8%5%344446%7%10%45%
1440
21st to endNight
12%42433447%8%49%
1440
July1st to 10thNight
6%314425%47%10%54%
1440
11th to 20thNight
6%22432445%10%59%
1440
21st to endNight
6%3245%25%5%5%9%54%
1634
August1st to 10thNight
5%4244345%7%9%53%
1611
11th to 20thNight
8%42443446%8%53%
1618
21st to endNight
9%42342445%5%57%
1980
September1st to 10thNight
11%425%5%3335%5%54%
1800
11th to 20thNight
12%434434447%54%
1800
21st to endNight
9%42342445%7%56%
2038
October1st to 10thNight
13%6%25%423346%52%
2160
11th to 20thNight
16%6%35%5%24346%45%
2160
21st to endNight
17%9%35%5%34445%41%
2399
November1st to 10thNight
11%6%34424446%51%
2406
11th to 20thNight
13%9%5%7%6%24447%39%
2603
21st to endNight
16%9%36%434446%41%
2660
December1st to 10thNight
13%10%48%7%45%5%5%6%33%
2660
11th to 20thNight
14%11%5%8%6%3445%7%33%
3279
21st to endNight
21%16%6%10%7%34445%19%
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
59%5%12%13%9%1
1518
11th to 20thDay
59%5%13%15%7%1
1511
21st to endDay
61%5%12%14%7%1
1782
February1st to 10thDay
55%5%14%17%7%1
1620
11th to 20thDay
51%6%12%22%9%1
1587
21st to endDay
52%6%13%19%8%2
1480
March1st to 10thDay
50%5%15%21%7%1
1888
11th to 20thDay
48%6%13%22%11%
1980
21st to endDay
58%5%10%19%7%1
2240
April1st to 10thDay
53%5%12%22%8%
2160
11th to 20thDay
51%6%10%21%11%1
2134
21st to endDay
51%5%11%20%12%2
2194
May1st to 10thDay
52%8%13%19%8%1
2422
11th to 20thDay
48%6%13%22%11%1
2483
21st to endDay
45%8%12%19%13%2
2725
June1st to 10thDay
35%9%14%25%15%1
2520
11th to 20thDay
36%7%12%22%21%3
2520
21st to endDay
41%8%13%23%14%1
2520
July1st to 10thDay
32%8%13%30%15%2
2451
11th to 20thDay
33%9%15%24%16%3
2445
21st to endDay
30%9%18%25%16%3
2532
August1st to 10thDay
35%10%15%27%11%2
2314
11th to 20thDay
36%7%14%28%15%2
2281
21st to endDay
33%6%11%27%20%2
2376
September1st to 10thDay
36%5%12%24%20%3
2160
11th to 20thDay
32%6%12%32%17%1
2160
21st to endDay
36%5%11%31%16%1
1898
October1st to 10thDay
40%7%10%26%17%1
1800
11th to 20thDay
47%311%23%15%2
1800
21st to endDay
45%6%12%23%13%1
1955
November1st to 10thDay
39%5%13%27%13%3
1672
11th to 20thDay
49%5%14%19%12%1
1575
21st to endDay
47%6%16%23%9%
1520
December1st to 10thDay
55%6%12%18%8%2
1520
11th to 20thDay
53%5%17%16%9%1
1915
21st to endDay
72%410%9%4
2783
January1st to 10thNight
48%414%20%13%1
2648
11th to 20thNight
59%5%15%14%7%
2508
21st to endNight
56%6%12%16%9%1
2574
February1st to 10thNight
54%411%19%11%1
2340
11th to 20thNight
46%412%24%12%2
2268
21st to endNight
49%412%19%13%3
1776
March1st to 10thNight
46%413%27%10%1
2088
11th to 20thNight
44%5%13%21%15%2
1980
21st to endNight
56%6%11%17%8%1
2116
April1st to 10thNight
46%5%9%25%14%2
1800
11th to 20thNight
47%5%8%21%15%3
1775
21st to endNight
45%5%11%24%14%2
1763
May1st to 10thNight
43%8%13%20%15%1
1535
11th to 20thNight
43%6%13%25%11%2
1417
21st to endNight
39%8%13%22%16%3
1552
June1st to 10thNight
30%8%16%26%16%3
1440
11th to 20thNight
32%8%13%22%20%4
1440
21st to endNight
31%7%15%27%15%4
1440
July1st to 10thNight
25%8%15%32%16%4
1400
11th to 20thNight
21%7%17%33%18%4
1392
21st to endNight
27%6%15%29%19%3
1543
August1st to 10thNight
27%7%17%33%14%3
1601
11th to 20thNight
30%6%13%32%18%2
1618
21st to endNight
29%6%11%25%23%6%
1980
September1st to 10thNight
32%6%10%25%25%2
1800
11th to 20thNight
31%5%10%32%21%2
1800
21st to endNight
29%6%11%30%23%2
2038
October1st to 10thNight
34%5%10%25%24%3
2160
11th to 20thNight
41%411%24%18%2
2160
21st to endNight
45%5%11%22%15%2
2399
November1st to 10thNight
35%414%25%19%4
2406
11th to 20thNight
46%412%24%12%1
2603
21st to endNight
46%412%26%11%1
2660
December1st to 10thNight
51%5%12%22%8%1
2660
11th to 20thNight
52%5%13%23%6%1
3281
21st to endNight
68%5%8%13%6%
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
18%13%34%25%8%2
270
11th to 20thDay
18%13%43%21%5%
248
21st to endDay
20%14%34%26%5%2
264
February1st to 10thDay
17%20%40%20%3
240
11th to 20thDay
22%18%32%20%8%
240
21st to endDay
23%13%42%16%5%
198
March1st to 10thDay
14%20%42%17%6%1
240
11th to 20thDay
21%14%33%21%9%2
240
21st to endDay
32%16%28%17%7%1
326
April1st to 10thDay
23%14%40%17%6%
420
11th to 20thDay
23%17%29%22%9%1
412
21st to endDay
26%14%33%16%10%2
454
May1st to 10thDay
23%12%33%23%8%1
603
11th to 20thDay
21%14%26%24%11%3
625
21st to endDay
16%10%29%25%16%5%
679
June1st to 10thDay
10%428%32%21%6%
630
11th to 20thDay
13%6%29%33%18%3
630
21st to endDay
10%7%33%31%14%5%
630
July1st to 10thDay
8%317%35%23%14%
621
11th to 20thDay
8%328%31%24%7%
618
21st to endDay
6%325%36%25%5%
684
August1st to 10thDay
7%322%31%28%8%
626
11th to 20thDay
11%6%19%30%24%10%
595
21st to endDay
8%423%33%23%8%
495
September1st to 10thDay
16%5%23%30%20%6%
450
11th to 20thDay
9%424%35%21%7%
450
21st to endDay
13%12%29%26%17%2
325
October1st to 10thDay
20%8%30%25%13%4
270
11th to 20thDay
26%20%32%14%8%
270
21st to endDay
22%17%35%18%6%3
297
November1st to 10thDay
16%11%38%24%9%3
270
11th to 20thDay
16%23%27%25%7%1
270
21st to endDay
26%11%35%23%5%
270
December1st to 10thDay
13%13%43%22%7%2
270
11th to 20thDay
18%13%35%23%9%1
270
21st to endDay
26%19%37%16%2
297
January1st to 10thNight
14%14%37%27%7%
950
11th to 20thNight
17%13%35%29%6%
915
21st to endNight
19%12%35%29%5%
990
February1st to 10thNight
18%12%38%26%5%
900
11th to 20thNight
16%12%38%27%6%
873
21st to endNight
18%14%38%25%41
592
March1st to 10thNight
20%13%36%25%6%1
648
11th to 20thNight
18%9%34%29%10%1
540
21st to endNight
24%11%36%22%6%1
594
April1st to 10thNight
20%11%41%24%3
540
11th to 20thNight
20%12%35%26%7%
533
21st to endNight
21%9%36%26%8%1
540
May1st to 10thNight
18%9%34%31%7%1
540
11th to 20thNight
18%9%30%33%10%1
531
21st to endNight
16%5%30%33%16%2
584
June1st to 10thNight
9%427%43%16%1
540
11th to 20thNight
9%331%43%13%1
540
21st to endNight
12%427%40%16%1
540
July1st to 10thNight
6%114%44%31%3
525
11th to 20thNight
6%219%43%27%3
522
21st to endNight
6%121%49%22%2
591
August1st to 10thNight
6%214%48%28%2
537
11th to 20thNight
8%316%42%27%4
534
21st to endNight
10%218%43%24%3
594
September1st to 10thNight
11%420%39%20%4
540
11th to 20thNight
12%321%36%25%2
540
21st to endNight
10%8%29%34%18%1
657
October1st to 10thNight
15%6%29%34%14%1
720
11th to 20thNight
19%11%33%28%8%
720
21st to endNight
22%11%31%28%8%
792
November1st to 10thNight
15%9%39%28%9%
740
11th to 20thNight
17%13%40%23%7%
893
21st to endNight
20%11%37%24%8%
950
December1st to 10thNight
17%13%39%25%6%1
950
11th to 20thNight
22%9%35%27%6%
950
21st to endNight
26%12%35%23%4
1045
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