Berne
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Berne clear sky chart from 2005-11-05 to 2017-09-19.

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
39%
15816
17%
46810
11%
15774
44%
15774
22%
31826

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 15thNight
17%
900
11%
2506
5%
895
23%
895
12%
1989
January16th to endNight
20%
867
12%
2595
5%
867
26%
867
13%
2001
February1st to 15thNight
21%
701
10%
2175
4%
701
27%
701
13%
1611
February16th to endNight
22%
631
14%
1893
6%
631
29%
631
15%
1400
March1st to 15thNight
29%
720
14%
2112
9%
720
33%
720
16%
1543
March16th to endNight
29%
768
16%
2112
8%
768
36%
768
21%
1491
April1st to 15thNight
30%
539
16%
1797
9%
539
39%
539
20%
1193
April16th to endNight
37%
540
21%
1647
11%
540
45%
540
24%
1066
May1st to 15thNight
36%
540
14%
1620
8%
540
42%
540
20%
1150
May16th to endNight
51%
562
16%
1683
11%
561
56%
561
29%
1051
June1st to 15thNight
57%
540
18%
1440
12%
540
62%
540
37%
893
June16th to endNight
56%
540
18%
1440
12%
540
61%
540
34%
919
July1st to 15thNight
62%
510
16%
1360
13%
510
64%
510
35%
861
July16th to endNight
72%
564
21%
1497
18%
531
75%
531
44%
835
August1st to 15thNight
68%
539
22%
1609
18%
536
70%
536
37%
905
August16th to endNight
70%
573
20%
1836
20%
573
73%
573
35%
1022
September1st to 15thNight
65%
639
26%
1899
23%
639
68%
639
35%
1102
September16th to endNight
61%
673
25%
1858
19%
673
65%
673
35%
1135
October1st to 15thNight
50%
660
25%
1848
19%
660
55%
660
33%
1136
October16th to endNight
31%
704
18%
2233
13%
704
39%
704
21%
1463
November1st to 15thNight
38%
700
25%
2276
18%
700
48%
700
27%
1377
November16th to endNight
26%
720
16%
2340
11%
720
33%
720
15%
1681
December1st to 15thNight
21%
726
10%
2346
5%
726
27%
726
12%
1797
December16th to endNight
16%
960
9%
2688
2%
960
22%
960
11%
2205

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%45%7%34%
48001
Night
15%8%35%5%24446%37%
46987
Cloud CoverDay
14%8%36%5%35%45%7%34%
48010
Night
15%8%36%5%24446%37%
46992
TransparencyDay
48%5%12%20%12%1
47696
Night
47%411%21%13%1
46810
SeeingDay
17%6%23%24%18%9%
5826
Night
19%8%26%29%15%1
15820

By Month

Percentage Cloud Cover NE (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 15thDay
20%16%6%8%6%34335%20%
1432
16th to endDay
13%17%8%9%7%45%445%19%
1627
February1st to 15thDay
15%14%7%10%6%35%346%22%
1685
16th to endDay
13%14%5%11%7%34336%23%
1580
March1st to 15thDay
21%11%5%6%6%24346%26%
1838
16th to endDay
20%8%48%6%2345%8%28%
2121
April1st to 15thDay
18%8%36%5%2445%7%32%
2151
16th to endDay
18%6%26%43345%7%36%
2313
May1st to 15thDay
19%8%36%6%46%446%28%
2331
16th to endDay
12%5%25%6%35%5%5%8%38%
2431
June1st to 15thDay
12%4246%36%5%5%7%41%
2518
16th to endDay
11%335%5%36%5%6%10%36%
2520
July1st to 15thDay
9%425%6%45%5%6%9%39%
2520
16th to endDay
6%435%6%35%6%7%9%40%
2566
August1st to 15thDay
6%425%5%35%6%7%9%43%
2340
16th to endDay
8%4245%35%5%7%9%42%
2364
September1st to 15thDay
12%5%26%4235%46%44%
2049
16th to endDay
14%4245%3445%7%43%
1848
October1st to 15thDay
12%5%36%5%3445%5%42%
1782
16th to endDay
20%7%245%3445%7%33%
1636
November1st to 15thDay
13%6%245%23346%46%
1582
16th to endDay
19%10%5%7%6%34335%28%
1620
December1st to 15thDay
19%17%7%9%5%14335%21%
1611
16th to endDay
21%17%6%9%6%23345%18%
1536
January1st to 15thNight
20%13%6%8%6%2443424%
2506
16th to endNight
15%14%6%8%6%35%435%25%
2595
February1st to 15thNight
17%13%6%6%6%34445%28%
2173
16th to endNight
15%11%6%8%8%34445%29%
1893
March1st to 15thNight
16%11%36%5%35%445%32%
2099
16th to endNight
15%9%36%6%35%346%35%
2112
April1st to 15thNight
18%7%3443445%7%35%
1797
16th to endNight
15%7%25%43445%6%40%
1647
May1st to 15thNight
19%7%36%5%44447%32%
1620
16th to endNight
13%423425%36%9%44%
1681
June1st to 15thNight
9%3245%25%45%7%48%
1440
16th to endNight
8%5%245%35%46%9%44%
1440
July1st to 15thNight
7%415%435%5%5%8%46%
1440
16th to endNight
5%3245%3436%10%52%
1600
August1st to 15thNight
5%425%5%245%5%9%50%
1620
16th to endNight
7%32442445%8%51%
1836
September1st to 15thNight
11%423323447%52%
1899
16th to endNight
12%41342445%6%50%
1858
October1st to 15thNight
13%42442335%6%48%
1848
16th to endNight
20%6%25%5%23445%39%
2233
November1st to 15thNight
13%7%34423446%45%
2276
16th to endNight
21%10%47%433346%29%
2340
December1st to 15thNight
22%12%6%7%5%33345%25%
2346
16th to endNight
23%15%6%7%5%24345%19%
2688

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 15thDay
19%16%6%9%6%34335%20%
1432
16th to endDay
12%18%8%9%7%45%445%19%
1627
February1st to 15thDay
15%14%7%11%6%35%346%21%
1685
16th to endDay
13%14%5%11%7%34336%23%
1580
March1st to 15thDay
21%11%6%6%6%24346%26%
1848
16th to endDay
20%8%47%6%3335%8%28%
2120
April1st to 15thDay
18%8%36%5%2445%7%32%
2151
16th to endDay
18%6%26%43435%7%37%
2313
May1st to 15thDay
19%9%36%6%46%446%28%
2331
16th to endDay
11%425%6%36%5%5%8%38%
2431
June1st to 15thDay
12%425%5%36%5%5%8%41%
2518
16th to endDay
11%435%5%36%5%6%10%36%
2520
July1st to 15thDay
9%4246%45%6%6%9%39%
2520
16th to endDay
6%435%6%35%7%7%10%40%
2566
August1st to 15thDay
6%425%5%45%5%7%10%43%
2340
16th to endDay
8%4245%35%5%7%9%42%
2364
September1st to 15thDay
12%5%25%5%24447%44%
2049
16th to endDay
14%4245%2445%7%43%
1848
October1st to 15thDay
12%5%26%6%3445%5%42%
1782
16th to endDay
20%7%245%3445%7%33%
1636
November1st to 15thDay
13%6%245%23346%46%
1582
16th to endDay
20%11%5%7%6%34335%28%
1620
December1st to 15thDay
18%18%7%9%5%24435%21%
1611
16th to endDay
20%17%6%10%6%23345%18%
1536
January1st to 15thNight
20%13%6%8%6%3443424%
2506
16th to endNight
16%14%6%8%6%44435%25%
2595
February1st to 15thNight
16%13%6%6%6%34445%28%
2166
16th to endNight
15%11%6%8%7%34435%28%
1893
March1st to 15thNight
17%11%46%5%35%5%45%31%
2112
16th to endNight
15%9%36%6%34347%35%
2112
April1st to 15thNight
18%7%345%2445%7%35%
1797
16th to endNight
15%7%25%5%2445%7%39%
1647
May1st to 15thNight
19%7%36%5%44447%32%
1619
16th to endNight
13%423425%36%9%44%
1681
June1st to 15thNight
8%3145%25%45%7%48%
1440
16th to endNight
8%5%245%25%45%9%44%
1440
July1st to 15thNight
7%415%435%5%6%8%46%
1440
16th to endNight
43245%3436%10%52%
1600
August1st to 15thNight
5%425%5%25%46%9%50%
1620
16th to endNight
7%32442445%7%51%
1836
September1st to 15thNight
11%424313447%52%
1899
16th to endNight
12%42342445%6%50%
1858
October1st to 15thNight
13%5%2442335%6%48%
1848
16th to endNight
19%6%15%5%23445%39%
2233
November1st to 15thNight
13%7%25%42335%6%45%
2276
16th to endNight
21%10%47%5%33346%29%
2340
December1st to 15thNight
22%13%6%7%5%23345%25%
2346
16th to endNight
23%15%6%7%6%2434419%
2688

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 15thDay
67%48%14%5%
1433
16th to endDay
66%412%11%5%
1627
February1st to 15thDay
63%310%14%7%
1687
16th to endDay
61%311%17%41
1580
March1st to 15thDay
59%412%16%6%
1848
16th to endDay
53%415%19%5%1
2121
April1st to 15thDay
51%411%21%10%
2151
16th to endDay
46%412%19%12%4
2313
May1st to 15thDay
55%5%11%18%8%
2331
16th to endDay
42%6%12%21%13%1
2435
June1st to 15thDay
39%5%11%25%15%1
2518
16th to endDay
40%6%14%20%15%2
2520
July1st to 15thDay
39%5%11%22%18%2
2371
16th to endDay
35%7%16%24%13%1
2406
August1st to 15thDay
32%7%15%26%16%1
2327
16th to endDay
35%6%13%23%15%4
2364
September1st to 15thDay
39%5%11%22%18%3
2049
16th to endDay
40%49%22%22%1
1848
October1st to 15thDay
41%6%9%23%17%2
1782
16th to endDay
49%312%22%10%
1636
November1st to 15thDay
39%310%24%19%2
1582
16th to endDay
58%310%19%7%
1620
December1st to 15thDay
66%310%14%4
1611
16th to endDay
68%310%12%3
1536
January1st to 15thNight
64%38%14%8%
2506
16th to endNight
62%311%16%6%
2595
February1st to 15thNight
58%312%16%7%
2175
16th to endNight
57%311%18%8%
1893
March1st to 15thNight
54%5%10%18%9%1
2112
16th to endNight
50%411%23%9%1
2112
April1st to 15thNight
47%311%21%14%1
1797
16th to endNight
43%410%20%15%5%
1647
May1st to 15thNight
51%5%12%20%9%1
1620
16th to endNight
36%7%13%22%16%3
1683
June1st to 15thNight
33%5%9%28%20%2
1440
16th to endNight
35%6%14%23%16%3
1440
July1st to 15thNight
35%5%11%22%20%3
1360
16th to endNight
25%5%16%31%16%4
1497
August1st to 15thNight
28%6%15%24%22%2
1609
16th to endNight
30%5%14%22%22%4
1836
September1st to 15thNight
31%5%10%26%21%4
1899
16th to endNight
34%49%23%24%2
1858
October1st to 15thNight
35%410%24%22%1
1848
16th to endNight
46%310%26%12%1
2233
November1st to 15thNight
38%48%24%20%3
2276
16th to endNight
56%210%20%8%
2340
December1st to 15thNight
61%411%15%7%
2346
16th to endNight
67%39%13%5%
2688

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 15thDay
28%14%34%14%6%1
90
16th to endDay
27%15%38%13%5%
96
February1st to 15thDay
27%22%42%6%1
90
16th to endDay
20%12%40%18%6%1
81
March1st to 15thDay
34%10%24%28%
138
16th to endDay
24%10%30%23%9%1
288
April1st to 15thDay
21%12%28%25%10%1
270
16th to endDay
22%8%25%24%12%6%
270
May1st to 15thDay
26%8%23%24%11%5%
288
16th to endDay
16%6%25%24%17%10%
331
June1st to 15thDay
12%422%33%20%6%
493
16th to endDay
16%427%25%18%7%
495
July1st to 15thDay
12%225%26%19%13%
475
16th to endDay
8%13%29%29%18%
426
August1st to 15thDay
9%111%27%26%22%
313
16th to endDay
11%314%19%30%20%
332
September1st to 15thDay
15%211%20%32%16%
315
16th to endDay
16%413%17%31%16%
266
October1st to 15thDay
12%6%23%27%21%8%
255
16th to endDay
25%6%31%28%7%
148
November1st to 15thDay
12%11%23%20%25%7%
90
16th to endDay
31%11%37%10%10%
90
December1st to 15thDay
26%18%33%13%7%
90
16th to endDay
25%20%40%11%2
96
January1st to 15thNight
25%14%34%19%4
900
16th to endNight
23%15%32%24%4
867
February1st to 15thNight
24%11%34%25%3
704
16th to endNight
21%12%35%26%4
631
March1st to 15thNight
23%11%29%27%7%
720
16th to endNight
18%9%33%26%9%1
768
April1st to 15thNight
20%10%34%27%6%
539
16th to endNight
20%6%31%28%10%2
540
May1st to 15thNight
23%428%32%10%
540
16th to endNight
14%226%31%21%2
563
June1st to 15thNight
11%121%44%20%
540
16th to endNight
11%122%38%26%
540
July1st to 15thNight
10%17%40%27%2
510
16th to endNight
7%110%41%35%3
564
August1st to 15thNight
6%111%41%30%6%
539
16th to endNight
7%18%35%41%5%
573
September1st to 15thNight
13%312%33%30%5%
639
16th to endNight
13%5%14%31%31%4
673
October1st to 15thNight
15%423%31%20%4
660
16th to endNight
23%11%29%25%9%
704
November1st to 15thNight
16%10%31%26%14%1
700
16th to endNight
25%12%29%22%8%
720
December1st to 15thNight
27%12%30%22%6%
726
16th to endNight
31%11%31%19%4
960
Page generated at 2017-09-20 04:49:45. Version ac04

Copyright 2017 A. Danko


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