Observatoire d'Astronomie Berrada
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatoire d'Astronomie Berrada clear sky chart from 2005-11-05 to 2018-01-20.

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
26%
15090
12%
48483
7%
15058
33%
15058
14%
35306

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
13%
780
7%
2716
2%
776
20%
776
7%
2177
January16th to endNight
18%
788
9%
2756
4%
788
25%
788
10%
2091
February1st to 15thNight
15%
704
10%
2305
3%
701
23%
701
10%
1768
February16th to endNight
17%
631
11%
1916
5%
631
26%
631
11%
1459
March1st to 15thNight
17%
720
12%
2154
6%
720
24%
720
12%
1653
March16th to endNight
27%
768
19%
1995
7%
768
35%
768
21%
1389
April1st to 15thNight
22%
718
15%
1796
5%
718
28%
718
18%
1347
April16th to endNight
25%
627
15%
1707
6%
627
33%
627
20%
1190
May1st to 15thNight
27%
360
14%
1440
11%
360
39%
360
14%
998
May16th to endNight
27%
375
12%
1497
10%
374
38%
374
16%
996
June1st to 15thNight
28%
360
6%
1440
5%
360
34%
360
12%
1014
June16th to endNight
43%
360
7%
1440
9%
360
46%
360
16%
969
July1st to 15thNight
48%
340
10%
1360
14%
340
53%
340
24%
793
July16th to endNight
49%
376
12%
1418
13%
354
53%
354
22%
868
August1st to 15thNight
53%
365
13%
1436
12%
363
58%
363
20%
917
August16th to endNight
47%
741
17%
1887
9%
741
51%
741
31%
1233
September1st to 15thNight
40%
720
13%
1800
6%
720
43%
720
27%
1255
September16th to endNight
42%
717
20%
1954
12%
717
47%
717
30%
1267
October1st to 15thNight
28%
720
16%
2145
9%
720
38%
720
18%
1512
October16th to endNight
20%
768
11%
2451
5%
768
28%
768
11%
1889
November1st to 15thNight
23%
760
15%
2498
9%
760
32%
760
12%
1833
November16th to endNight
19%
780
11%
2730
7%
780
24%
780
9%
2112
December1st to 15thNight
14%
780
7%
2730
2%
780
19%
780
7%
2214
December16th to endNight
10%
832
9%
2912
3%
832
17%
832
5%
2362

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
19%11%47%6%34446%27%
49051
Night
17%11%47%5%34446%29%
48652
Cloud CoverDay
18%10%47%6%34446%28%
49060
Night
16%10%47%6%3445%6%30%
48658
TransparencyDay
56%5%10%17%8%1
48738
Night
54%5%11%18%8%
48483
SeeingDay
25%15%28%19%7%2
5861
Night
23%15%28%22%9%1
15090

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%8%10%8%3433317%
1552
16th to endDay
11%14%8%10%8%445%45%21%
1572
February1st to 15thDay
9%16%7%11%10%35%345%22%
1554
16th to endDay
13%19%6%9%7%3443422%
1557
March1st to 15thDay
15%13%6%10%7%44335%25%
1793
16th to endDay
15%11%36%5%24346%34%
2228
April1st to 15thDay
21%13%46%423335%29%
2152
16th to endDay
20%10%35%5%23345%33%
2261
May1st to 15thDay
23%10%36%6%2435%5%27%
2511
16th to endDay
23%8%46%6%43445%28%
2618
June1st to 15thDay
25%8%36%5%35%5%5%6%25%
2520
16th to endDay
23%7%36%6%35%6%5%6%25%
2520
July1st to 15thDay
18%6%36%5%35%5%5%7%31%
2520
16th to endDay
15%7%36%6%45%5%5%8%29%
2654
August1st to 15thDay
19%8%27%6%45%6%6%6%26%
2513
16th to endDay
13%5%36%5%445%5%9%36%
2303
September1st to 15thDay
20%6%36%44435%6%34%
2160
16th to endDay
19%7%24323445%42%
2005
October1st to 15thDay
26%10%35%423435%30%
1812
16th to endDay
27%14%47%6%2334420%
1772
November1st to 15thDay
18%13%5%6%6%34446%26%
1690
16th to endDay
22%16%5%7%5%24335%22%
1560
December1st to 15thDay
21%19%7%8%5%23345%17%
1560
16th to endDay
19%18%8%9%7%3434416%
1664
January1st to 15thNight
16%17%8%10%8%35%45%5%15%
2716
16th to endNight
10%15%8%9%7%45%5%6%6%20%
2756
February1st to 15thNight
9%15%7%10%8%45%435%23%
2303
16th to endNight
14%13%5%12%6%3445%6%22%
1916
March1st to 15thNight
17%12%5%8%6%45%35%5%25%
2141
16th to endNight
13%9%35%5%34446%37%
1995
April1st to 15thNight
24%10%35%5%23435%31%
1796
16th to endNight
18%8%35%42445%5%36%
1707
May1st to 15thNight
21%9%45%424346%33%
1440
16th to endNight
20%6%36%5%34446%35%
1495
June1st to 15thNight
21%8%36%5%345%5%7%28%
1440
16th to endNight
19%6%245%35%5%5%7%34%
1440
July1st to 15thNight
14%42442445%9%43%
1440
16th to endNight
10%5%245%345%7%8%41%
1514
August1st to 15thNight
12%6%35%4346%7%7%37%
1446
16th to endNight
12%4244245%5%7%45%
1887
September1st to 15thNight
17%7%24425%447%40%
1800
16th to endNight
17%5%24422346%46%
1954
October1st to 15thNight
19%8%26%5%3434435%
2145
16th to endNight
26%13%37%423345%23%
2451
November1st to 15thNight
19%10%47%6%35%45%6%27%
2498
16th to endNight
20%17%48%5%2444421%
2730
December1st to 15thNight
20%17%8%10%6%24335%17%
2730
16th to endNight
18%18%7%9%7%4434416%
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%16%8%9%8%3433318%
1552
16th to endDay
11%15%6%12%7%35%5%4423%
1572
February1st to 15thDay
9%16%6%10%9%44446%22%
1554
16th to endDay
14%18%6%9%7%2443424%
1557
March1st to 15thDay
15%13%6%10%7%34335%25%
1803
16th to endDay
15%10%37%6%24446%35%
2227
April1st to 15thDay
21%12%45%5%23435%30%
2152
16th to endDay
20%10%46%333345%33%
2261
May1st to 15thDay
22%10%47%6%2435%6%27%
2511
16th to endDay
22%9%36%5%34446%28%
2618
June1st to 15thDay
24%7%36%6%36%5%5%6%25%
2520
16th to endDay
22%7%35%7%35%6%5%6%25%
2520
July1st to 15thDay
17%6%35%6%35%5%6%7%31%
2520
16th to endDay
15%6%36%6%46%5%6%8%29%
2654
August1st to 15thDay
18%7%36%7%46%6%5%7%26%
2513
16th to endDay
12%6%26%5%3445%9%37%
2303
September1st to 15thDay
19%6%36%6%33446%35%
2160
16th to endDay
18%6%25%323346%43%
2005
October1st to 15thDay
24%9%26%423347%29%
1812
16th to endDay
27%12%48%7%23335%21%
1772
November1st to 15thDay
17%12%47%6%34446%27%
1690
16th to endDay
22%15%48%5%2434424%
1560
December1st to 15thDay
21%19%6%8%5%3343419%
1560
16th to endDay
19%17%9%9%6%33345%17%
1664
January1st to 15thNight
16%16%8%9%7%3445%5%17%
2716
16th to endNight
9%15%7%9%8%45%45%7%22%
2756
February1st to 15thNight
9%15%7%10%8%45%45%5%24%
2296
16th to endNight
14%13%5%10%6%345%5%7%24%
1916
March1st to 15thNight
17%12%49%5%45%345%26%
2154
16th to endNight
13%9%36%5%2445%5%39%
1995
April1st to 15thNight
23%8%36%423435%31%
1796
16th to endNight
18%8%35%5%2446%6%35%
1707
May1st to 15thNight
19%10%45%5%34335%34%
1440
16th to endNight
20%6%35%43445%7%35%
1495
June1st to 15thNight
21%8%36%43445%7%29%
1440
16th to endNight
18%7%25%425%5%6%7%34%
1440
July1st to 15thNight
13%5%145%235%6%8%43%
1440
16th to endNight
9%6%245%35%6%6%8%41%
1514
August1st to 15thNight
11%6%25%5%15%6%6%8%38%
1446
16th to endNight
11%4244245%5%7%46%
1887
September1st to 15thNight
16%6%2443445%7%40%
1800
16th to endNight
17%5%14323346%46%
1954
October1st to 15thNight
17%9%25%6%3434436%
2145
16th to endNight
24%11%46%5%24445%25%
2451
November1st to 15thNight
19%9%36%6%35%45%6%28%
2498
16th to endNight
19%15%5%8%6%24346%23%
2730
December1st to 15thNight
19%15%8%9%7%2434419%
2730
16th to endNight
18%16%6%10%7%34345%18%
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
72%36%12%4
1553
16th to endDay
61%5%7%15%8%1
1572
February1st to 15thDay
63%38%16%6%
1556
16th to endDay
63%46%14%8%1
1557
March1st to 15thDay
62%39%14%9%1
1803
16th to endDay
49%49%17%15%3
2228
April1st to 15thDay
55%38%18%11%2
2152
16th to endDay
53%5%7%17%12%3
2261
May1st to 15thDay
57%47%17%11%1
2511
16th to endDay
56%5%10%17%9%1
2622
June1st to 15thDay
58%6%11%14%8%
2520
16th to endDay
56%7%10%17%7%1
2520
July1st to 15thDay
46%7%15%20%8%
2371
16th to endDay
51%8%15%17%8%
2487
August1st to 15thDay
54%8%15%17%4
2499
16th to endDay
43%6%17%22%9%
2303
September1st to 15thDay
49%5%12%21%10%
2160
16th to endDay
42%5%11%29%10%
2005
October1st to 15thDay
55%5%9%21%7%
1812
16th to endDay
66%410%13%4
1772
November1st to 15thDay
56%5%13%15%7%1
1690
16th to endDay
63%49%14%6%1
1560
December1st to 15thDay
69%410%12%3
1560
16th to endDay
70%46%10%7%
1664
January1st to 15thNight
68%410%12%4
2716
16th to endNight
61%410%14%8%1
2756
February1st to 15thNight
61%410%16%5%
2305
16th to endNight
59%5%9%14%9%1
1916
March1st to 15thNight
59%5%9%15%8%1
2154
16th to endNight
46%410%18%17%1
1995
April1st to 15thNight
53%47%21%11%2
1796
16th to endNight
47%5%11%18%14%2
1707
May1st to 15thNight
52%5%8%16%12%3
1440
16th to endNight
48%6%11%20%11%1
1497
June1st to 15thNight
53%7%12%18%7%
1440
16th to endNight
47%8%11%20%11%
1440
July1st to 15thNight
35%7%18%25%11%
1360
16th to endNight
38%9%18%24%10%
1418
August1st to 15thNight
40%10%19%23%6%
1436
16th to endNight
35%8%17%30%9%
1887
September1st to 15thNight
42%7%14%24%10%
1800
16th to endNight
39%415%31%9%
1954
October1st to 15thNight
50%410%22%10%
2145
16th to endNight
61%410%17%5%
2451
November1st to 15thNight
55%6%12%17%7%1
2498
16th to endNight
63%5%9%15%5%1
2730
December1st to 15thNight
68%410%12%3
2730
16th to endNight
69%47%10%6%
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
27%16%35%17%2
90
16th to endDay
26%21%35%10%22
73
February1st to 15thDay
29%25%35%5%3
87
16th to endDay
30%18%31%16%2
216
March1st to 15thDay
25%23%30%17%2
270
16th to endDay
26%17%27%18%7%2
288
April1st to 15thDay
31%19%24%16%7%1
270
16th to endDay
28%18%26%17%7%2
270
May1st to 15thDay
30%18%26%15%5%2
288
16th to endDay
28%13%33%16%7%
331
June1st to 15thDay
28%15%31%17%6%
315
16th to endDay
24%15%33%18%6%1
315
July1st to 15thDay
18%10%37%24%6%2
305
16th to endDay
17%6%33%31%8%2
326
August1st to 15thDay
20%6%30%27%13%2
313
16th to endDay
17%9%31%19%12%9%
332
September1st to 15thDay
21%11%23%22%13%6%
315
16th to endDay
18%13%21%23%14%8%
314
October1st to 15thDay
28%16%23%18%10%2
315
16th to endDay
36%16%22%16%7%
298
November1st to 15thDay
27%17%24%22%7%1
254
16th to endDay
38%27%22%11%
90
December1st to 15thDay
35%17%32%12%2
90
16th to endDay
31%27%30%8%3
96
January1st to 15thNight
25%21%31%16%5%
780
16th to endNight
19%17%34%20%6%1
788
February1st to 15thNight
18%21%35%18%4
704
16th to endNight
22%19%33%19%4
631
March1st to 15thNight
25%19%32%19%2
720
16th to endNight
20%16%31%22%6%2
768
April1st to 15thNight
28%17%26%23%4
718
16th to endNight
25%16%29%19%8%
627
May1st to 15thNight
24%12%30%22%8%1
360
16th to endNight
22%10%36%22%8%
375
June1st to 15thNight
26%10%26%28%7%
360
16th to endNight
21%424%33%15%1
360
July1st to 15thNight
15%6%25%33%17%
340
16th to endNight
11%5%28%36%15%1
376
August1st to 15thNight
15%319%38%21%
365
16th to endNight
14%7%25%30%19%2
741
September1st to 15thNight
19%7%27%30%14%1
720
16th to endNight
19%10%22%26%19%2
717
October1st to 15thNight
23%14%26%22%12%
720
16th to endNight
32%16%25%19%5%
768
November1st to 15thNight
25%18%26%18%8%1
760
16th to endNight
29%22%24%15%6%1
780
December1st to 15thNight
30%21%26%17%4
780
16th to endNight
30%20%28%14%41
832
Page generated at 2018-01-21 12:19:28. Version ac04

Copyright 2018 A. Danko


Observatoire d'Astronomie Berrada Clear Sky Chart |Charts Home