Mont Ham-Nord
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mont Ham-Nord 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
25%
14663
11%
46979
6%
14631
31%
14631
13%
35767

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
12%
720
6%
2506
3%
716
15%
716
6%
2115
January16th to endNight
16%
768
7%
2688
4%
768
21%
768
7%
2222
February1st to 15thNight
13%
704
7%
2327
3%
701
19%
701
7%
1926
February16th to endNight
14%
631
10%
1893
4%
631
22%
631
10%
1522
March1st to 15thNight
17%
720
13%
2160
7%
720
25%
720
11%
1685
March16th to endNight
27%
768
16%
2019
6%
768
34%
768
17%
1517
April1st to 15thNight
23%
718
14%
1796
4%
718
29%
718
17%
1397
April16th to endNight
24%
560
16%
1640
5%
560
33%
560
18%
1156
May1st to 15thNight
27%
465
14%
1545
10%
465
35%
465
16%
1093
May16th to endNight
29%
375
10%
1497
10%
374
37%
374
12%
1054
June1st to 15thNight
30%
360
7%
1377
6%
360
35%
360
12%
1007
June16th to endNight
39%
360
7%
1381
9%
360
43%
360
16%
947
July1st to 15thNight
45%
340
9%
1360
14%
340
48%
340
17%
900
July16th to endNight
45%
376
10%
1418
12%
354
48%
354
16%
938
August1st to 15thNight
46%
419
11%
1490
10%
417
49%
417
17%
1015
August16th to endNight
48%
672
16%
1818
9%
672
51%
672
27%
1228
September1st to 15thNight
42%
720
11%
1842
6%
720
43%
720
24%
1319
September16th to endNight
42%
673
19%
1858
13%
673
46%
673
28%
1213
October1st to 15thNight
29%
660
15%
1899
8%
660
36%
660
19%
1383
October16th to endNight
21%
704
8%
2288
4%
704
26%
704
10%
1791
November1st to 15thNight
21%
700
13%
2277
9%
700
28%
700
11%
1730
November16th to endNight
21%
722
12%
2452
9%
722
26%
722
9%
1918
December1st to 15thNight
10%
750
4%
2700
1%
750
14%
750
5%
2312
December16th to endNight
10%
778
6%
2748
3%
778
15%
778
4%
2379

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
21%11%47%6%34445%25%
47815
Night
19%12%5%7%6%34445%27%
47149
TransparencyDay
59%5%10%16%6%
47503
Night
59%5%10%16%7%
46979
SeeingDay
29%13%26%18%9%2
5787
Night
26%13%26%22%8%
14663

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%18%7%12%9%3344312%
1432
16th to endDay
11%16%9%10%11%44445%17%
1536
February1st to 15thDay
12%20%8%11%10%45%42314%
1531
16th to endDay
14%18%8%10%9%5%5%43417%
1580
March1st to 15thDay
18%14%6%9%6%2345%423%
1790
16th to endDay
17%13%5%8%6%3333429%
2202
April1st to 15thDay
23%14%46%5%2334327%
2152
16th to endDay
22%12%35%5%2334432%
2319
May1st to 15thDay
25%8%36%5%43345%28%
2415
16th to endDay
24%8%37%5%3445%6%25%
2618
June1st to 15thDay
29%7%25%43445%7%24%
2574
16th to endDay
24%8%35%6%35%46%6%25%
2570
July1st to 15thDay
20%6%35%5%35%5%5%8%29%
2520
16th to endDay
22%6%36%5%46%5%6%8%24%
2654
August1st to 15thDay
23%6%26%6%36%5%6%7%24%
2446
16th to endDay
18%6%25%5%34447%36%
2382
September1st to 15thDay
24%6%2442435%5%35%
2118
16th to endDay
20%7%24334347%37%
1848
October1st to 15thDay
25%12%35%424335%28%
1729
16th to endDay
28%17%37%5%34335%17%
1584
November1st to 15thDay
20%18%37%5%23345%25%
1581
16th to endDay
19%19%7%8%42323423%
1501
December1st to 15thDay
24%20%6%10%5%2323315%
1260
16th to endDay
23%20%9%9%7%3422214%
1473
January1st to 15thNight
16%16%9%12%8%45%33416%
2506
16th to endNight
11%16%8%11%9%47%5%4317%
2688
February1st to 15thNight
11%14%8%13%11%45%43418%
2326
16th to endNight
15%17%5%11%7%25%34323%
1893
March1st to 15thNight
18%14%6%7%6%2333427%
2147
16th to endNight
16%10%46%6%346%3433%
2019
April1st to 15thNight
24%11%46%5%2444427%
1796
16th to endNight
22%8%35%32345%5%35%
1640
May1st to 15thNight
23%8%45%42245%5%31%
1545
16th to endNight
22%7%36%435%5%47%29%
1495
June1st to 15thNight
28%7%35%5%2436%7%26%
1377
16th to endNight
20%5%25%6%25%46%7%31%
1381
July1st to 15thNight
16%6%26%435%45%8%34%
1440
16th to endNight
16%5%35%6%35%5%5%7%35%
1514
August1st to 15thNight
16%6%36%5%345%5%8%34%
1500
16th to endNight
16%6%2442445%7%40%
1818
September1st to 15thNight
22%7%2442345%5%37%
1842
16th to endNight
21%413323435%45%
1858
October1st to 15thNight
21%9%36%42345%6%31%
1899
16th to endNight
27%12%36%5%3433423%
2288
November1st to 15thNight
20%12%5%6%5%33445%26%
2277
16th to endNight
22%15%6%9%5%2333325%
2452
December1st to 15thNight
22%19%8%12%6%2322215%
2700
16th to endNight
22%20%6%10%7%4433314%
2748

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
76%47%8%3
1433
16th to endDay
70%48%13%3
1536
February1st to 15thDay
75%35%10%3
1534
16th to endDay
72%36%10%5%1
1580
March1st to 15thDay
63%410%13%7%1
1800
16th to endDay
59%48%15%10%1
2202
April1st to 15thDay
60%48%15%9%2
2152
16th to endDay
55%48%16%12%2
2319
May1st to 15thDay
57%410%16%9%1
2415
16th to endDay
58%6%11%15%8%
2622
June1st to 15thDay
58%6%11%15%6%
2574
16th to endDay
56%7%10%19%6%
2570
July1st to 15thDay
49%8%15%20%5%
2371
16th to endDay
56%9%12%17%5%
2487
August1st to 15thDay
54%10%16%16%2
2432
16th to endDay
45%7%14%23%9%
2382
September1st to 15thDay
49%6%13%21%9%
2118
16th to endDay
45%5%12%26%9%
1848
October1st to 15thDay
58%5%11%19%6%
1729
16th to endDay
69%48%13%3
1584
November1st to 15thDay
61%5%10%14%7%
1581
16th to endDay
66%310%13%5%
1501
December1st to 15thDay
75%48%9%2
1260
16th to endDay
78%35%6%5%
1473
January1st to 15thNight
73%48%10%2
2506
16th to endNight
70%5%7%12%3
2688
February1st to 15thNight
70%47%12%4
2327
16th to endNight
65%48%11%9%
1893
March1st to 15thNight
62%47%15%8%1
2160
16th to endNight
54%5%9%15%12%2
2019
April1st to 15thNight
58%46%16%12%1
1796
16th to endNight
49%5%10%19%12%3
1640
May1st to 15thNight
52%5%9%18%12%1
1545
16th to endNight
53%7%11%18%8%
1497
June1st to 15thNight
57%6%11%17%6%
1377
16th to endNight
49%7%12%20%9%
1381
July1st to 15thNight
44%9%15%20%8%
1360
16th to endNight
46%8%15%20%9%
1418
August1st to 15thNight
46%9%17%22%4
1490
16th to endNight
40%7%17%25%9%
1818
September1st to 15thNight
47%6%13%25%7%
1842
16th to endNight
40%413%29%11%
1858
October1st to 15thNight
52%5%12%20%9%
1899
16th to endNight
63%410%15%5%
2288
November1st to 15thNight
59%5%13%14%5%2
2277
16th to endNight
64%48%15%6%
2452
December1st to 15thNight
75%47%9%2
2700
16th to endNight
77%46%7%4
2748

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
25%21%35%15%3
60
16th to endDay
28%26%29%12%11
64
February1st to 15thDay
31%21%29%14%3
132
16th to endDay
29%17%29%19%3
239
March1st to 15thDay
28%24%23%19%3
270
16th to endDay
26%16%28%13%12%3
288
April1st to 15thDay
36%17%22%15%5%2
270
16th to endDay
29%18%26%14%6%4
270
May1st to 15thDay
37%11%27%14%6%1
288
16th to endDay
28%16%29%16%8%
331
June1st to 15thDay
33%11%26%18%8%
369
16th to endDay
26%10%33%22%7%
365
July1st to 15thDay
24%7%33%20%10%2
305
16th to endDay
24%7%29%28%9%1
326
August1st to 15thDay
27%8%26%21%14%1
313
16th to endDay
21%11%23%19%17%6%
332
September1st to 15thDay
24%8%23%22%13%6%
315
16th to endDay
20%12%24%19%15%7%
266
October1st to 15thDay
28%12%24%17%14%3
250
16th to endDay
40%15%19%15%9%
240
November1st to 15thDay
31%15%25%18%6%
235
16th to endDay
36%16%21%15%8%2
135
December1st to 15thDay
41%18%28%10%1
60
16th to endDay
42%21%29%41
64
January1st to 15thNight
25%22%30%18%3
720
16th to endNight
23%20%31%19%4
768
February1st to 15thNight
19%20%33%21%4
704
16th to endNight
25%18%32%18%4
631
March1st to 15thNight
28%17%31%19%3
720
16th to endNight
22%17%26%24%7%1
768
April1st to 15thNight
31%13%27%22%4
718
16th to endNight
28%14%28%19%8%
560
May1st to 15thNight
27%11%29%22%7%1
465
16th to endNight
26%9%28%27%8%
375
June1st to 15thNight
30%8%23%28%9%
360
16th to endNight
22%426%35%10%
360
July1st to 15thNight
16%6%25%33%16%1
340
16th to endNight
16%425%36%16%
376
August1st to 15thNight
20%5%19%33%20%
419
16th to endNight
20%320%32%19%2
672
September1st to 15thNight
25%6%21%31%13%1
720
16th to endNight
23%6%25%25%16%2
673
October1st to 15thNight
26%11%28%20%11%1
660
16th to endNight
34%16%24%19%4
704
November1st to 15thNight
28%16%27%19%8%
700
16th to endNight
32%17%22%18%9%
722
December1st to 15thNight
34%19%27%14%3
750
16th to endNight
35%18%26%15%3
778
Page generated at 2017-09-20 04:49:51. Version ac04

Copyright 2017 A. Danko


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