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 2018-10-27.

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%
17293
17%
51174
11%
17251
45%
17251
22%
34710

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%
975
11%
2716
5%
970
23%
970
12%
2152
January16th to endNight
19%
939
13%
2811
5%
939
27%
939
13%
2154
February1st to 15thNight
20%
761
10%
2360
4%
761
26%
761
13%
1762
February16th to endNight
21%
683
14%
2049
6%
683
29%
683
15%
1532
March1st to 15thNight
29%
780
15%
2288
10%
780
34%
780
17%
1647
March16th to endNight
30%
832
17%
2288
9%
832
37%
832
21%
1615
April1st to 15thNight
29%
584
15%
1947
9%
584
38%
584
20%
1307
April16th to endNight
37%
579
20%
1764
11%
579
45%
579
24%
1143
May1st to 15thNight
37%
585
14%
1755
8%
585
42%
585
21%
1233
May16th to endNight
51%
610
15%
1827
10%
609
56%
609
29%
1145
June1st to 15thNight
57%
585
19%
1560
12%
585
63%
585
36%
968
June16th to endNight
57%
585
18%
1560
12%
585
62%
585
34%
990
July1st to 15thNight
64%
555
18%
1480
15%
555
66%
555
35%
926
July16th to endNight
72%
612
20%
1632
17%
579
74%
579
42%
923
August1st to 15thNight
69%
575
22%
1715
19%
572
71%
572
38%
959
August16th to endNight
70%
621
20%
1990
19%
621
72%
621
35%
1113
September1st to 15thNight
65%
692
26%
2057
23%
692
67%
692
34%
1210
September16th to endNight
61%
777
27%
2145
20%
777
66%
777
36%
1301
October1st to 15thNight
49%
780
24%
2184
18%
780
54%
780
32%
1363
October16th to endNight
31%
816
20%
2586
14%
816
40%
816
22%
1671
November1st to 15thNight
38%
760
23%
2471
17%
760
48%
760
26%
1514
November16th to endNight
27%
780
17%
2535
11%
780
34%
780
16%
1789
December1st to 15thNight
22%
787
10%
2542
5%
787
28%
787
13%
1912
December16th to endNight
15%
1040
9%
2912
3%
1040
22%
1040
11%
2381

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%3445%7%34%
52376
Night
15%8%35%5%34446%37%
51351
Cloud CoverDay
14%8%36%5%35%45%7%34%
52385
Night
15%8%36%5%24446%37%
51356
TransparencyDay
48%5%12%20%12%1
52071
Night
46%411%21%13%1
51174
SeeingDay
18%6%23%24%18%8%
7319
Night
19%7%26%29%15%1
17297

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
19%16%6%9%7%34335%19%
1552
16th to endDay
13%18%7%9%6%45%445%20%
1763
February1st to 15thDay
16%14%7%10%6%34345%21%
1830
16th to endDay
15%14%5%11%7%34336%23%
1710
March1st to 15thDay
20%11%5%6%6%24446%26%
1992
16th to endDay
21%8%37%6%2345%8%28%
2298
April1st to 15thDay
18%8%36%6%2445%7%31%
2331
16th to endDay
18%6%27%43345%7%36%
2471
May1st to 15thDay
17%8%36%7%46%447%29%
2526
16th to endDay
12%5%25%6%35%6%6%8%38%
2639
June1st to 15thDay
12%5%246%36%5%5%7%41%
2728
16th to endDay
12%325%5%36%5%6%10%36%
2730
July1st to 15thDay
9%4245%45%5%6%9%42%
2730
16th to endDay
7%435%6%35%6%7%9%39%
2783
August1st to 15thDay
6%425%5%35%5%7%9%43%
2487
16th to endDay
9%4245%35%6%6%9%42%
2562
September1st to 15thDay
13%5%25%4245%46%44%
2220
16th to endDay
14%42442445%7%45%
2145
October1st to 15thDay
13%6%26%6%3445%6%39%
2106
16th to endDay
19%8%245%3445%6%35%
1892
November1st to 15thDay
14%6%245%33346%44%
1717
16th to endDay
19%10%5%7%6%34335%30%
1755
December1st to 15thDay
17%16%7%9%6%14335%22%
1745
16th to endDay
21%17%6%9%6%33345%18%
1664
January1st to 15thNight
19%13%6%8%6%3443424%
2716
16th to endNight
15%14%6%8%6%34435%26%
2811
February1st to 15thNight
18%13%6%6%6%3444428%
2358
16th to endNight
17%11%5%8%7%34445%28%
2049
March1st to 15thNight
16%11%36%5%35%445%33%
2275
16th to endNight
16%8%36%6%34346%35%
2288
April1st to 15thNight
19%7%35%5%2445%7%34%
1947
16th to endNight
15%7%25%434446%39%
1764
May1st to 15thNight
17%7%36%5%44447%33%
1755
16th to endNight
13%413425%46%9%43%
1825
June1st to 15thNight
9%2245%26%45%7%48%
1560
16th to endNight
8%5%245%3446%9%45%
1560
July1st to 15thNight
7%415%435%5%5%8%48%
1560
16th to endNight
5%3245%3446%9%50%
1735
August1st to 15thNight
5%4244245%5%9%50%
1726
16th to endNight
7%32442445%8%51%
1990
September1st to 15thNight
12%423323447%50%
2057
16th to endNight
11%41342345%6%51%
2145
October1st to 15thNight
14%5%2442335%7%46%
2184
16th to endNight
19%6%25%423435%41%
2586
November1st to 15thNight
14%7%34423446%44%
2471
16th to endNight
20%10%46%5%33346%31%
2535
December1st to 15thNight
21%12%6%7%5%23345%26%
2542
16th to endNight
22%15%6%7%6%24445%19%
2912

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%17%6%9%6%34335%19%
1552
16th to endDay
13%18%7%9%7%45%445%19%
1763
February1st to 15thDay
16%14%7%11%6%34345%21%
1830
16th to endDay
15%14%5%11%7%34336%23%
1710
March1st to 15thDay
20%11%6%6%6%24346%26%
2002
16th to endDay
21%8%37%6%3335%7%28%
2297
April1st to 15thDay
18%8%46%6%2445%7%31%
2331
16th to endDay
18%6%26%43335%7%37%
2471
May1st to 15thDay
17%8%36%6%46%447%29%
2526
16th to endDay
11%435%6%35%5%6%8%38%
2639
June1st to 15thDay
12%425%5%36%5%5%7%40%
2728
16th to endDay
11%435%5%36%5%6%10%36%
2730
July1st to 15thDay
8%4245%45%5%6%9%41%
2730
16th to endDay
7%435%5%45%7%7%10%39%
2783
August1st to 15thDay
6%425%5%35%5%7%10%43%
2487
16th to endDay
9%4245%35%5%7%9%42%
2562
September1st to 15thDay
13%5%25%5%24446%44%
2220
16th to endDay
14%5%145%24447%45%
2145
October1st to 15thDay
13%6%26%6%3445%6%39%
2106
16th to endDay
19%8%245%3445%6%35%
1892
November1st to 15thDay
14%6%245%33346%44%
1717
16th to endDay
19%11%5%7%6%34335%30%
1755
December1st to 15thDay
17%17%7%9%5%2443422%
1745
16th to endDay
20%17%6%10%6%33345%17%
1664
January1st to 15thNight
19%13%6%8%6%3443423%
2716
16th to endNight
15%14%6%8%6%34435%26%
2811
February1st to 15thNight
17%13%6%6%6%34435%27%
2351
16th to endNight
17%11%6%8%7%34435%27%
2049
March1st to 15thNight
16%11%46%5%34445%33%
2288
16th to endNight
16%8%36%6%24347%35%
2288
April1st to 15thNight
19%7%35%5%2445%7%34%
1947
16th to endNight
15%7%25%5%2445%7%39%
1764
May1st to 15thNight
17%7%37%444447%33%
1754
16th to endNight
13%423425%46%8%44%
1825
June1st to 15thNight
8%3145%35%45%7%48%
1560
16th to endNight
8%5%245%25%46%9%45%
1560
July1st to 15thNight
7%315%435%5%6%8%48%
1560
16th to endNight
5%3245%3446%9%51%
1735
August1st to 15thNight
5%425%5%25%46%8%50%
1726
16th to endNight
7%32442445%7%51%
1990
September1st to 15thNight
12%423313447%50%
2057
16th to endNight
11%42342445%6%51%
2145
October1st to 15thNight
13%5%2442335%6%46%
2184
16th to endNight
19%6%25%5%23445%41%
2586
November1st to 15thNight
13%7%35%42335%6%43%
2471
16th to endNight
20%10%47%5%34346%30%
2535
December1st to 15thNight
21%12%6%7%5%23345%26%
2542
16th to endNight
22%15%6%7%6%24445%19%
2912

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
68%48%13%5%
1553
16th to endDay
65%412%12%5%
1763
February1st to 15thDay
63%310%14%7%
1832
16th to endDay
61%310%16%5%1
1710
March1st to 15thDay
58%311%17%6%
2002
16th to endDay
53%414%19%5%1
2298
April1st to 15thDay
52%412%20%10%
2331
16th to endDay
46%312%19%13%4
2471
May1st to 15thDay
53%6%12%18%8%
2526
16th to endDay
42%6%12%21%13%1
2643
June1st to 15thDay
40%5%11%25%15%1
2728
16th to endDay
40%7%13%21%14%2
2730
July1st to 15thDay
37%5%12%22%18%3
2581
16th to endDay
37%7%15%23%13%2
2623
August1st to 15thDay
32%6%15%26%16%1
2474
16th to endDay
35%6%13%23%15%4
2562
September1st to 15thDay
39%5%12%21%18%3
2220
16th to endDay
38%410%23%21%1
2145
October1st to 15thDay
43%6%9%22%15%2
2106
16th to endDay
48%311%22%12%
1892
November1st to 15thDay
41%310%23%17%2
1717
16th to endDay
57%311%20%7%
1755
December1st to 15thDay
65%39%15%5%
1745
16th to endDay
68%310%11%3
1664
January1st to 15thNight
63%48%14%9%
2716
16th to endNight
61%311%17%6%
2811
February1st to 15thNight
59%312%15%8%
2360
16th to endNight
59%310%17%8%
2049
March1st to 15thNight
52%5%10%19%10%1
2288
16th to endNight
50%410%23%10%1
2288
April1st to 15thNight
48%311%21%13%1
1947
16th to endNight
43%49%20%15%5%
1764
May1st to 15thNight
50%5%12%20%9%1
1755
16th to endNight
36%7%13%22%15%3
1827
June1st to 15thNight
33%5%10%28%20%2
1560
16th to endNight
34%7%14%25%15%2
1560
July1st to 15thNight
33%6%11%23%20%4
1480
16th to endNight
27%5%16%29%16%4
1632
August1st to 15thNight
28%5%14%25%23%2
1715
16th to endNight
30%5%14%22%22%4
1990
September1st to 15thNight
32%5%11%25%20%4
2057
16th to endNight
33%49%24%25%2
2145
October1st to 15thNight
37%411%24%21%1
2184
16th to endNight
44%39%26%13%1
2586
November1st to 15thNight
40%49%24%19%3
2471
16th to endNight
54%211%22%8%
2535
December1st to 15thNight
59%410%16%8%
2542
16th to endNight
66%49%13%5%
2912

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
26%11%36%17%7%
135
16th to endDay
29%13%39%13%3
144
February1st to 15thDay
32%17%39%9%
135
16th to endDay
31%13%34%15%4
120
March1st to 15thDay
28%12%29%27%1
187
16th to endDay
27%9%29%24%8%
352
April1st to 15thDay
24%13%27%24%9%1
330
16th to endDay
22%9%24%22%14%5%
319
May1st to 15thDay
23%8%24%26%11%6%
348
16th to endDay
16%5%22%26%18%11%
395
June1st to 15thDay
12%422%32%21%6%
568
16th to endDay
15%425%25%20%7%
570
July1st to 15thDay
11%222%25%22%16%
550
16th to endDay
10%12%30%29%17%
499
August1st to 15thDay
9%110%29%27%21%
358
16th to endDay
12%314%21%30%17%
396
September1st to 15thDay
17%29%20%33%16%
375
16th to endDay
16%414%19%29%15%
374
October1st to 15thDay
17%6%24%25%20%6%
375
16th to endDay
23%8%30%29%7%
240
November1st to 15thDay
20%10%25%17%20%5%
135
16th to endDay
25%13%38%13%8%
135
December1st to 15thDay
21%23%31%13%8%
135
16th to endDay
27%20%37%13%1
144
January1st to 15thNight
24%13%35%20%4
975
16th to endNight
22%15%34%23%4
939
February1st to 15thNight
25%10%34%25%3
764
16th to endNight
23%11%34%25%4
683
March1st to 15thNight
22%10%30%28%6%
780
16th to endNight
19%9%32%27%9%1
832
April1st to 15thNight
22%9%34%27%5%
584
16th to endNight
21%6%30%27%11%2
579
May1st to 15thNight
21%429%32%11%
585
16th to endNight
14%225%31%22%3
611
June1st to 15thNight
11%121%44%21%
585
16th to endNight
10%121%38%26%1
585
July1st to 15thNight
10%16%38%29%4
555
16th to endNight
7%19%41%35%3
612
August1st to 15thNight
6%110%41%32%6%
575
16th to endNight
8%18%36%39%5%
621
September1st to 15thNight
15%311%32%31%5%
692
16th to endNight
12%414%31%31%4
777
October1st to 15thNight
16%5%22%32%20%3
780
16th to endNight
22%11%30%25%9%
816
November1st to 15thNight
18%9%30%26%13%1
760
16th to endNight
24%13%30%23%8%
780
December1st to 15thNight
26%13%30%22%6%
787
16th to endNight
30%11%33%20%4
1040
Page generated at 2018-10-28 08:41:05. Version ac04

Copyright 2018 A. Danko


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