Barb's Ridge
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Barb's Ridge clear sky chart from 2005-11-06 to 2024-01-12.

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
48%
23609
22%
74470
17%
23552
55%
23552
26%
46370

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%
760
21%
2459
11%
757
38%
757
19%
1606
January11th to 20thNight
26%
728
19%
2365
11%
728
36%
728
16%
1652
January21st to endNight
28%
792
27%
2438
13%
792
42%
792
22%
1582
February1st to 10thNight
28%
720
21%
2160
11%
720
38%
720
23%
1437
February11th to 20thNight
22%
703
17%
2098
7%
699
31%
699
18%
1468
February21st to endNight
24%
592
20%
1776
10%
592
32%
592
17%
1254
March1st to 10thNight
33%
720
22%
2160
14%
720
42%
720
24%
1389
March11th to 20thNight
32%
720
17%
2008
9%
720
38%
720
22%
1385
March21st to endNight
34%
792
19%
2178
10%
792
41%
792
25%
1463
April1st to 10thNight
45%
540
27%
1800
19%
540
56%
540
29%
1026
April11th to 20thNight
42%
533
28%
1775
20%
533
54%
533
31%
1003
April21st to endNight
53%
540
26%
1720
21%
540
59%
540
32%
988
May1st to 10thNight
53%
540
23%
1620
15%
540
59%
540
34%
944
May11th to 20thNight
57%
531
19%
1593
14%
531
61%
531
29%
993
May21st to endNight
65%
582
19%
1744
16%
582
67%
582
32%
1056
June1st to 10thNight
63%
540
18%
1620
14%
540
65%
540
29%
1000
June11th to 20thNight
79%
540
20%
1620
17%
540
80%
540
46%
849
June21st to endNight
73%
540
18%
1620
15%
540
75%
540
37%
938
July1st to 10thNight
67%
525
13%
1575
13%
525
68%
525
28%
1009
July11th to 20thNight
74%
522
16%
1566
16%
522
75%
522
33%
925
July21st to endNight
72%
591
17%
1672
16%
558
72%
558
31%
1047
August1st to 10thNight
78%
537
18%
1651
19%
534
79%
534
33%
971
August11th to 20thNight
66%
534
16%
1776
18%
534
66%
534
28%
1068
August21st to endNight
68%
594
19%
1980
23%
594
69%
594
26%
1241
September1st to 10thNight
68%
612
21%
1872
20%
612
70%
612
32%
1131
September11th to 20thNight
62%
720
23%
1980
20%
720
64%
720
33%
1228
September21st to endNight
65%
720
29%
1980
22%
720
69%
720
38%
1173
October1st to 10thNight
62%
720
32%
1980
27%
720
66%
720
42%
1116
October11th to 20thNight
50%
720
30%
2011
22%
720
57%
720
33%
1229
October21st to endNight
51%
792
30%
2494
27%
792
59%
792
32%
1430
November1st to 10thNight
54%
740
27%
2406
26%
740
60%
740
32%
1341
November11th to 20thNight
43%
760
29%
2470
21%
760
55%
760
31%
1419
November21st to endNight
43%
760
25%
2470
20%
760
51%
760
25%
1526
December1st to 10thNight
32%
760
21%
2470
15%
760
42%
760
18%
1682
December11th to 20thNight
38%
759
24%
2929
17%
758
47%
758
19%
1804
December21st to endNight
29%
830
13%
4434
12%
817
37%
817
10%
2997

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%6%35%6%45%5%6%7%39%
74844
Night
14%6%35%5%345%5%7%43%
74889
TransparencyDay
43%411%21%17%4
74567
Night
41%411%22%19%5%
74685
SeeingDay
18%10%22%22%18%10%
13533
Night
17%9%19%30%22%4
23618

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
20%8%35%43445%6%39%
1706
11th to 20thDay
23%7%46%5%3434436%
1635
21st to endDay
16%6%445%2445%6%44%
1915
February1st to 10thDay
19%10%37%5%2445%6%36%
1800
11th to 20thDay
24%7%36%6%245%45%34%
1748
21st to endDay
23%9%35%434345%37%
1480
March1st to 10thDay
15%7%25%6%3445%7%41%
1800
11th to 20thDay
21%8%27%5%3445%6%36%
1950
21st to endDay
17%7%36%6%36%5%6%6%35%
2192
April1st to 10thDay
12%6%35%446%45%7%43%
2160
11th to 20thDay
14%7%36%4335%46%45%
2134
21st to endDay
13%5%25%5%45%5%5%8%43%
2237
May1st to 10thDay
13%6%25%5%345%6%7%44%
2340
11th to 20thDay
12%7%37%6%46%5%6%7%38%
2301
21st to endDay
10%5%25%6%47%6%8%9%39%
2531
June1st to 10thDay
9%6%36%6%5%6%7%8%10%35%
2340
11th to 20thDay
6%325%5%5%6%8%7%11%43%
2340
21st to endDay
7%435%7%6%6%8%8%11%36%
2340
July1st to 10thDay
8%437%8%6%8%7%8%10%30%
2340
11th to 20thDay
11%5%26%7%5%7%7%9%10%31%
2340
21st to endDay
7%5%36%7%6%8%8%9%11%30%
2547
August1st to 10thDay
8%6%26%8%7%7%8%9%10%29%
2272
11th to 20thDay
9%6%36%7%5%7%8%9%9%31%
2125
21st to endDay
13%6%37%8%5%7%7%7%8%31%
2376
September1st to 10thDay
10%6%36%6%46%6%7%8%37%
2070
11th to 20thDay
12%6%35%6%45%6%6%6%41%
1980
21st to endDay
12%5%246%3435%6%49%
1980
October1st to 10thDay
11%5%24424445%54%
1980
11th to 20thDay
11%5%245%2345%6%54%
1948
21st to endDay
15%5%24433445%51%
1858
November1st to 10thDay
11%5%24423345%56%
1672
11th to 20thDay
13%5%25%5%345%46%48%
1710
21st to endDay
18%7%2343445%7%44%
1710
December1st to 10thDay
22%9%36%5%335%45%34%
1710
11th to 20thDay
16%7%46%6%45%45%6%39%
2153
21st to endDay
18%10%5%5%5%35%5%5%7%31%
3124
January1st to 10thNight
20%8%35%435%346%40%
2459
11th to 20thNight
19%9%47%6%245%5%6%32%
2365
21st to endNight
16%7%45%5%3445%5%42%
2438
February1st to 10thNight
18%8%36%5%34345%40%
2160
11th to 20thNight
21%7%47%5%35%33437%
2098
21st to endNight
26%8%35%42445%5%34%
1776
March1st to 10thNight
16%6%345%3445%7%43%
2160
11th to 20thNight
16%8%37%5%3445%6%38%
2008
21st to endNight
14%8%36%6%35%45%7%40%
2178
April1st to 10thNight
12%5%145%35%5%6%7%49%
1800
11th to 20thNight
14%5%2432345%7%50%
1775
21st to endNight
11%5%25%4345%5%8%48%
1720
May1st to 10thNight
11%425%42446%7%50%
1620
11th to 20thNight
11%435%5%45%6%6%8%43%
1592
21st to endNight
8%5%25%5%35%5%7%10%43%
1744
June1st to 10thNight
6%6%36%6%46%5%7%10%40%
1620
11th to 20thNight
5%313326%48%10%55%
1620
21st to endNight
5%4245%36%5%7%12%47%
1620
July1st to 10thNight
8%5%36%7%46%6%8%9%39%
1620
11th to 20thNight
9%4243347%8%13%41%
1620
21st to endNight
6%5%25%6%46%6%9%13%38%
1771
August1st to 10thNight
7%315%5%36%8%8%11%43%
1662
11th to 20thNight
9%6%36%6%45%5%6%9%40%
1776
21st to endNight
10%5%45%5%46%6%7%10%38%
1980
September1st to 10thNight
9%5%26%5%35%6%6%9%43%
1872
11th to 20thNight
13%425%5%345%6%7%46%
1980
21st to endNight
10%5%235%25%5%46%53%
1980
October1st to 10thNight
11%42332335%6%59%
1980
11th to 20thNight
13%5%25%5%33446%50%
2011
21st to endNight
15%6%24323345%52%
2494
November1st to 10thNight
12%5%2442345%7%51%
2406
11th to 20thNight
12%6%34423346%51%
2470
21st to endNight
17%8%345%33446%44%
2470
December1st to 10thNight
20%9%46%5%345%5%5%35%
2470
11th to 20thNight
18%7%35%3235%5%6%43%
3042
21st to endNight
19%9%47%6%45%6%5%7%28%
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
47%36%21%19%3
1707
11th to 20thDay
53%26%18%17%3
1635
21st to endDay
42%27%25%21%3
1915
February1st to 10thDay
50%26%21%18%3
1800
11th to 20thDay
54%35%20%16%4
1758
21st to endDay
51%28%14%20%6%
1480
March1st to 10thDay
42%38%18%22%7%
1800
11th to 20thDay
52%39%16%16%4
1950
21st to endDay
48%410%24%13%1
2192
April1st to 10thDay
41%410%23%18%4
2160
11th to 20thDay
40%38%21%24%5%
2134
21st to endDay
40%310%29%16%2
2237
May1st to 10thDay
40%312%27%15%3
2340
11th to 20thDay
45%415%23%13%1
2305
21st to endDay
39%5%14%26%14%2
2531
June1st to 10thDay
41%6%15%22%14%1
2340
11th to 20thDay
34%5%18%27%14%2
2340
21st to endDay
40%7%17%20%13%3
2340
July1st to 10thDay
45%6%15%21%10%3
2275
11th to 20thDay
43%7%20%18%8%3
2271
21st to endDay
43%7%18%23%8%1
2405
August1st to 10thDay
45%7%18%22%8%1
2259
11th to 20thDay
43%6%15%21%13%1
2125
21st to endDay
49%6%14%16%11%3
2376
September1st to 10thDay
42%6%12%18%16%6%
2070
11th to 20thDay
42%5%10%21%19%3
1980
21st to endDay
36%49%22%22%7%
1980
October1st to 10thDay
34%37%22%27%8%
1980
11th to 20thDay
33%27%23%25%9%
1948
21st to endDay
36%25%23%27%7%
1858
November1st to 10thDay
34%26%20%31%8%
1672
11th to 20thDay
38%36%21%26%7%
1710
21st to endDay
42%25%22%24%4
1710
December1st to 10thDay
53%2420%18%3
1710
11th to 20thDay
50%16%17%21%4
2150
21st to endDay
53%27%21%14%3
3124
January1st to 10thNight
48%28%20%19%4
2459
11th to 20thNight
53%37%17%16%3
2365
21st to endNight
45%35%23%20%3
2438
February1st to 10thNight
47%38%19%20%4
2160
11th to 20thNight
52%36%18%16%6%
2099
21st to endNight
52%37%17%16%5%
1776
March1st to 10thNight
43%47%18%21%9%
2160
11th to 20thNight
47%49%18%17%4
2008
21st to endNight
46%39%25%15%2
2178
April1st to 10thNight
36%312%24%22%4
1800
11th to 20thNight
35%27%23%22%10%
1775
21st to endNight
36%310%30%20%2
1720
May1st to 10thNight
34%313%24%23%3
1620
11th to 20thNight
38%6%18%23%15%1
1593
21st to endNight
36%5%16%25%16%2
1745
June1st to 10thNight
38%6%16%24%15%3
1620
11th to 20thNight
23%5%21%34%15%2
1620
21st to endNight
29%7%20%25%14%4
1620
July1st to 10thNight
39%7%20%18%13%3
1575
11th to 20thNight
31%9%23%20%13%5%
1566
21st to endNight
36%7%22%24%9%2
1672
August1st to 10thNight
31%8%23%27%10%1
1651
11th to 20thNight
38%5%21%20%14%2
1776
21st to endNight
40%6%17%21%12%3
1980
September1st to 10thNight
36%5%18%21%16%4
1872
11th to 20thNight
36%5%13%20%23%3
1980
21st to endNight
32%49%23%24%8%
1980
October1st to 10thNight
28%48%24%27%9%
1980
11th to 20thNight
37%26%23%22%10%
2011
21st to endNight
36%2423%27%9%
2494
November1st to 10thNight
33%36%22%25%10%
2406
11th to 20thNight
36%25%21%28%9%
2470
21st to endNight
43%25%21%24%5%
2470
December1st to 10thNight
51%36%19%18%3
2470
11th to 20thNight
44%25%17%27%4
3044
21st to endNight
57%26%19%15%2
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
34%20%30%13%3
270
11th to 20thDay
33%22%26%11%7%1
245
21st to endDay
26%23%37%11%3
264
February1st to 10thDay
36%21%28%13%2
240
11th to 20thDay
44%24%25%6%
240
21st to endDay
41%23%29%6%1
198
March1st to 10thDay
30%20%33%15%21
240
11th to 20thDay
29%19%25%19%7%2
390
21st to endDay
29%17%28%17%9%
462
April1st to 10thDay
23%16%25%20%14%2
420
11th to 20thDay
19%16%30%21%12%2
412
21st to endDay
20%11%33%20%14%3
420
May1st to 10thDay
18%13%26%24%13%6%
423
11th to 20thDay
13%8%25%26%15%13%
447
21st to endDay
13%418%28%21%15%
485
June1st to 10thDay
11%6%16%27%22%17%
450
11th to 20thDay
7%5%12%28%27%21%
450
21st to endDay
10%418%25%24%18%
450
July1st to 10thDay
8%311%24%28%25%
445
11th to 20thDay
10%411%21%28%25%
444
21st to endDay
8%410%23%30%25%
488
August1st to 10thDay
10%312%24%29%22%
446
11th to 20thDay
10%5%9%30%31%15%
439
21st to endDay
15%47%25%32%18%
495
September1st to 10thDay
11%313%24%34%16%
450
11th to 20thDay
12%5%12%26%32%14%
450
21st to endDay
15%415%26%32%8%
450
October1st to 10thDay
13%5%20%30%24%8%
450
11th to 20thDay
13%10%27%29%16%4
450
21st to endDay
23%9%24%26%16%3
373
November1st to 10thDay
19%11%32%23%14%1
270
11th to 20thDay
14%20%36%23%6%
270
21st to endDay
21%15%36%17%10%1
270
December1st to 10thDay
32%17%29%17%5%1
270
11th to 20thDay
28%16%34%14%7%
270
21st to endDay
31%22%28%13%5%
297
January1st to 10thNight
28%15%27%26%5%
760
11th to 20thNight
26%18%25%25%7%
728
21st to endNight
23%15%30%28%4
792
February1st to 10thNight
25%11%30%29%5%
720
11th to 20thNight
29%17%29%23%2
703
21st to endNight
31%16%27%24%3
592
March1st to 10thNight
21%14%28%32%5%
720
11th to 20thNight
22%15%25%27%10%1
720
21st to endNight
21%12%27%28%12%
792
April1st to 10thNight
15%12%25%34%14%
540
11th to 20thNight
19%9%26%30%15%1
533
21st to endNight
14%7%20%41%16%2
540
May1st to 10thNight
12%6%22%35%22%3
540
11th to 20thNight
12%6%16%35%25%6%
531
21st to endNight
8%211%33%38%7%
584
June1st to 10thNight
8%212%34%38%7%
540
11th to 20thNight
428%34%38%14%
540
21st to endNight
6%29%29%45%9%
540
July1st to 10thNight
10%26%23%46%13%
525
11th to 20thNight
9%36%22%43%16%
522
21st to endNight
7%26%23%48%15%
591
August1st to 10thNight
7%1223%51%15%
537
11th to 20thNight
12%26%26%45%9%
534
21st to endNight
12%26%25%45%10%
594
September1st to 10thNight
10%17%28%42%11%
612
11th to 20thNight
15%29%28%38%7%
720
21st to endNight
11%313%32%38%4
720
October1st to 10thNight
12%416%31%29%8%
720
11th to 20thNight
16%8%19%33%23%1
720
21st to endNight
17%10%17%36%17%3
792
November1st to 10thNight
15%7%18%36%22%2
740
11th to 20thNight
16%11%26%33%13%1
760
21st to endNight
22%9%21%33%13%1
760
December1st to 10thNight
24%14%23%29%8%
760
11th to 20thNight
22%13%23%33%9%
760
21st to endNight
27%13%24%29%6%
836
Page generated at 2024-01-09 15:24:26. Version ac07

Copyright 2024 Attilla Danko


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