N5PA Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the N5PA Observatory clear sky chart from 2005-11-06 to 2024-01-14.

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
50%
23309
23%
74130
17%
23251
57%
23251
28%
44709

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
31%
894
26%
2402
9%
890
44%
890
29%
1507
January11th to 20thNight
31%
805
26%
2277
11%
805
42%
805
26%
1474
January21st to endNight
27%
792
28%
2376
10%
792
40%
792
23%
1518
February1st to 10thNight
30%
720
23%
2160
11%
720
40%
720
24%
1406
February11th to 20thNight
29%
703
21%
2099
9%
700
39%
700
23%
1372
February21st to endNight
19%
592
21%
1776
6%
592
31%
592
21%
1202
March1st to 10thNight
33%
720
24%
2160
13%
720
42%
720
28%
1315
March11th to 20thNight
31%
576
20%
2016
12%
576
42%
576
22%
1268
March21st to endNight
36%
594
26%
2016
16%
594
48%
594
29%
1141
April1st to 10thNight
38%
540
25%
1800
18%
540
49%
540
25%
1092
April11th to 20thNight
38%
533
23%
1775
17%
533
48%
533
28%
1060
April21st to endNight
51%
540
30%
1800
26%
540
62%
540
39%
925
May1st to 10thNight
55%
540
26%
1800
21%
540
65%
540
38%
951
May11th to 20thNight
63%
531
19%
1765
21%
531
67%
531
32%
1019
May21st to endNight
69%
582
22%
1744
20%
582
72%
582
34%
1035
June1st to 10thNight
64%
540
16%
1620
15%
540
65%
540
28%
1031
June11th to 20thNight
76%
540
21%
1512
19%
540
78%
540
38%
905
June21st to endNight
71%
540
19%
1440
17%
540
72%
540
35%
910
July1st to 10thNight
74%
525
13%
1501
13%
525
74%
525
28%
1005
July11th to 20thNight
76%
522
14%
1642
16%
522
77%
522
29%
1033
July21st to endNight
78%
591
14%
1858
17%
558
78%
558
26%
1172
August1st to 10thNight
82%
537
12%
1778
13%
534
83%
534
35%
1001
August11th to 20thNight
75%
534
15%
1776
18%
534
76%
534
23%
1175
August21st to endNight
70%
594
16%
1980
19%
594
71%
594
25%
1268
September1st to 10thNight
70%
540
19%
1800
21%
540
71%
540
25%
1159
September11th to 20thNight
67%
622
23%
1882
22%
622
68%
622
31%
1164
September21st to endNight
65%
720
29%
1980
23%
720
68%
720
38%
1167
October1st to 10thNight
64%
720
30%
1980
22%
720
68%
720
42%
1112
October11th to 20thNight
58%
720
34%
2150
26%
720
66%
720
38%
1204
October21st to endNight
53%
792
33%
2376
26%
792
60%
792
36%
1348
November1st to 10thNight
58%
740
31%
2291
25%
740
66%
740
40%
1229
November11th to 20thNight
47%
760
31%
2470
23%
760
58%
760
35%
1347
November21st to endNight
44%
760
28%
2470
20%
760
55%
760
29%
1451
December1st to 10thNight
38%
760
27%
2470
19%
760
50%
760
27%
1488
December11th to 20thNight
32%
760
23%
2899
14%
758
42%
758
19%
1788
December21st to endNight
29%
830
14%
4289
11%
817
38%
817
13%
2467

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
11%6%36%6%45%5%6%7%41%
75018
Night
12%6%25%5%345%5%8%46%
74693
TransparencyDay
40%6%11%18%18%6%
74754
Night
36%5%11%19%20%8%
74477
SeeingDay
15%8%20%24%22%11%
13644
Night
14%7%22%29%23%5%
23317

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
18%7%35%324445%44%
1745
11th to 20thDay
18%7%34434445%44%
1748
21st to endDay
19%6%36%432345%45%
1980
February1st to 10thDay
19%8%35%5%35%45%5%39%
1800
11th to 20thDay
19%7%25%424346%43%
1748
21st to endDay
17%9%37%5%23446%38%
1480
March1st to 10thDay
15%6%35%5%345%5%6%42%
1800
11th to 20thDay
16%6%37%6%35%5%5%7%37%
1956
21st to endDay
12%6%35%5%35%45%6%44%
2337
April1st to 10thDay
11%5%36%6%35%6%6%8%43%
2160
11th to 20thDay
15%6%25%6%345%5%6%42%
2134
21st to endDay
9%425%5%35%5%6%8%49%
2160
May1st to 10thDay
12%425%5%45%6%5%8%45%
2160
11th to 20thDay
8%5%27%6%46%6%7%9%40%
2124
21st to endDay
7%5%37%7%5%7%6%7%9%38%
2531
June1st to 10thDay
9%6%26%6%47%7%7%11%34%
2340
11th to 20thDay
5%425%6%6%7%8%8%10%41%
2438
21st to endDay
6%5%36%8%6%10%8%9%9%31%
2520
July1st to 10thDay
7%5%38%9%7%8%8%8%9%27%
2408
11th to 20thDay
9%5%37%8%5%8%9%9%10%28%
2259
21st to endDay
8%5%37%8%6%8%8%8%10%29%
2350
August1st to 10thDay
45%38%7%5%7%8%10%11%34%
2148
11th to 20thDay
9%7%38%9%5%7%7%6%9%31%
2125
21st to endDay
11%5%36%7%46%7%7%9%34%
2376
September1st to 10thDay
8%7%26%7%5%6%5%7%9%38%
2160
11th to 20thDay
11%7%35%5%36%6%6%7%42%
2057
21st to endDay
10%4245%3346%7%52%
1980
October1st to 10thDay
6%4244245%47%56%
1980
11th to 20thDay
10%5%245%3345%6%53%
1805
21st to endDay
12%426%433346%55%
1980
November1st to 10thDay
11%5%24333445%55%
1784
11th to 20thDay
13%5%24423445%54%
1710
21st to endDay
14%5%35%444447%48%
1710
December1st to 10thDay
14%7%36%43445%6%44%
1710
11th to 20thDay
14%11%35%5%3344443%
2153
21st to endDay
16%8%25%5%345%5%7%40%
3162
January1st to 10thNight
17%6%25%322346%48%
2402
11th to 20thNight
17%7%35%424445%45%
2277
21st to endNight
20%7%25%423345%45%
2376
February1st to 10thNight
16%8%35%5%3446%6%40%
2160
11th to 20thNight
19%8%35%423336%43%
2098
21st to endNight
20%8%36%5%34446%39%
1776
March1st to 10thNight
13%6%26%43345%7%47%
2160
11th to 20thNight
14%6%36%6%345%5%7%40%
2016
21st to endNight
13%5%25%323447%51%
2016
April1st to 10thNight
13%6%35%43445%7%47%
1800
11th to 20thNight
13%5%25%5%34447%47%
1775
21st to endNight
7%42432445%7%57%
1800
May1st to 10thNight
8%42433346%10%54%
1800
11th to 20thNight
7%5%245%36%5%6%9%48%
1765
21st to endNight
6%4245%46%7%7%12%44%
1744
June1st to 10thNight
7%6%36%6%45%6%7%10%40%
1620
11th to 20thNight
43246%46%7%8%12%45%
1512
21st to endNight
6%436%5%35%5%8%13%42%
1440
July1st to 10thNight
45%37%7%49%7%9%12%35%
1546
11th to 20thNight
6%5%25%6%46%7%9%13%38%
1696
21st to endNight
4326%7%5%8%7%9%11%39%
1968
August1st to 10thNight
33145%45%7%9%15%44%
1790
11th to 20thNight
8%425%6%47%7%10%12%35%
1776
21st to endNight
9%5%25%6%45%6%7%11%39%
1980
September1st to 10thNight
9%5%35%7%47%6%7%8%40%
1800
11th to 20thNight
8%5%37%6%35%5%6%7%45%
1882
21st to endNight
8%5%35%4245%47%53%
1980
October1st to 10thNight
7%42442445%7%57%
1980
11th to 20thNight
9%42443335%6%57%
2150
21st to endNight
13%5%34323435%56%
2376
November1st to 10thNight
10%424323245%60%
2291
11th to 20thNight
13%5%23323346%56%
2470
21st to endNight
13%6%25%43445%6%48%
2470
December1st to 10thNight
17%6%2443435%6%47%
2470
11th to 20thNight
16%8%35%5%24445%44%
3042
21st to endNight
18%8%25%42335%6%43%
4489

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
43%3320%23%7%
1746
11th to 20thDay
42%45%15%26%8%
1748
21st to endDay
43%2416%27%8%
1980
February1st to 10thDay
48%36%15%18%10%
1800
11th to 20thDay
43%46%16%24%8%
1758
21st to endDay
47%37%16%16%10%
1480
March1st to 10thDay
42%49%16%20%9%
1800
11th to 20thDay
45%5%8%14%19%8%
1956
21st to endDay
41%49%17%23%6%
2337
April1st to 10thDay
39%5%9%18%21%8%
2160
11th to 20thDay
42%5%6%17%22%8%
2134
21st to endDay
33%5%9%23%26%4
2160
May1st to 10thDay
36%5%9%21%23%5%
2160
11th to 20thDay
39%7%13%23%16%2
2128
21st to endDay
41%6%14%22%16%1
2531
June1st to 10thDay
41%7%15%23%12%2
2340
11th to 20thDay
34%8%18%23%14%2
2438
21st to endDay
43%10%16%19%10%1
2520
July1st to 10thDay
49%11%17%15%7%1
2344
11th to 20thDay
45%12%19%18%5%1
2190
21st to endDay
44%10%21%17%7%1
2219
August1st to 10thDay
39%9%22%22%7%
2136
11th to 20thDay
47%10%18%15%8%2
2125
21st to endDay
44%8%17%16%12%3
2376
September1st to 10thDay
41%7%16%16%14%6%
2160
11th to 20thDay
40%7%11%16%17%8%
2057
21st to endDay
31%6%10%23%19%10%
1980
October1st to 10thDay
28%410%19%28%11%
1980
11th to 20thDay
32%46%17%29%12%
1805
21st to endDay
32%3418%28%15%
1980
November1st to 10thDay
31%38%18%28%13%
1784
11th to 20thDay
33%36%15%28%15%
1710
21st to endDay
38%47%18%21%11%
1710
December1st to 10thDay
41%49%21%17%8%
1710
11th to 20thDay
46%36%13%24%8%
2150
21st to endDay
43%46%23%20%4
3162
January1st to 10thNight
38%37%18%27%7%
2402
11th to 20thNight
42%46%18%22%9%
2277
21st to endNight
44%3414%27%9%
2376
February1st to 10thNight
44%38%17%19%10%
2160
11th to 20thNight
45%36%14%22%11%
2099
21st to endNight
47%38%15%14%13%
1776
March1st to 10thNight
37%49%16%22%12%
2160
11th to 20thNight
43%5%11%15%19%7%
2016
21st to endNight
34%412%20%23%8%
2016
April1st to 10thNight
38%5%10%17%20%11%
1800
11th to 20thNight
38%410%20%21%8%
1775
21st to endNight
27%410%23%29%7%
1800
May1st to 10thNight
28%410%27%24%8%
1800
11th to 20thNight
32%7%16%24%19%2
1766
21st to endNight
30%9%16%23%19%3
1745
June1st to 10thNight
37%8%15%25%12%2
1620
11th to 20thNight
29%8%19%29%13%3
1512
21st to endNight
33%8%19%26%11%3
1440
July1st to 10thNight
37%11%22%21%6%3
1501
11th to 20thNight
33%11%29%20%6%1
1642
21st to endNight
34%12%24%23%5%1
1858
August1st to 10thNight
25%11%32%22%9%1
1778
11th to 20thNight
36%14%21%17%10%2
1776
21st to endNight
38%10%22%16%10%4
1980
September1st to 10thNight
40%8%17%14%15%7%
1800
11th to 20thNight
36%7%16%18%15%9%
1882
21st to endNight
31%5%10%25%19%10%
1980
October1st to 10thNight
27%5%11%17%24%16%
1980
11th to 20thNight
29%46%19%26%15%
2150
21st to endNight
32%35%16%25%18%
2376
November1st to 10thNight
28%37%19%27%16%
2291
11th to 20thNight
31%35%17%28%15%
2470
21st to endNight
37%46%21%19%13%
2470
December1st to 10thNight
38%49%22%20%7%
2470
11th to 20thNight
43%36%14%26%8%
3044
21st to endNight
43%36%19%25%4
4489

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
27%22%31%16%31
270
11th to 20thDay
24%17%31%19%7%1
249
21st to endDay
24%24%31%17%3
264
February1st to 10thDay
30%19%31%14%6%
240
11th to 20thDay
33%19%28%15%5%
240
21st to endDay
23%18%44%13%2
198
March1st to 10thDay
22%18%37%18%5%
240
11th to 20thDay
26%20%30%19%41
240
21st to endDay
21%15%33%22%9%
423
April1st to 10thDay
15%16%32%24%12%1
420
11th to 20thDay
22%14%28%22%12%2
412
21st to endDay
14%10%27%31%16%2
420
May1st to 10thDay
15%10%22%25%23%4
423
11th to 20thDay
10%424%30%21%11%
447
21st to endDay
8%316%32%27%14%
485
June1st to 10thDay
13%215%31%26%12%
450
11th to 20thDay
6%311%31%34%15%
548
21st to endDay
8%213%29%31%17%
630
July1st to 10thDay
7%18%27%36%20%
621
11th to 20thDay
9%1420%37%29%
537
21st to endDay
9%16%23%35%25%
488
August1st to 10thDay
6%19%20%33%31%
446
11th to 20thDay
11%16%17%40%25%
439
21st to endDay
15%27%18%31%27%
495
September1st to 10thDay
10%11%26%35%18%
450
11th to 20thDay
14%49%25%34%15%
450
21st to endDay
13%312%28%32%12%
450
October1st to 10thDay
7%6%19%34%25%8%
450
11th to 20thDay
12%5%22%29%27%5%
275
21st to endDay
20%12%16%33%15%4
297
November1st to 10thDay
16%7%26%35%11%4
270
11th to 20thDay
20%11%31%24%12%1
270
21st to endDay
17%16%33%20%11%3
270
December1st to 10thDay
23%13%34%21%9%1
270
11th to 20thDay
27%15%34%18%5%1
270
21st to endDay
29%15%29%21%5%1
297
January1st to 10thNight
22%13%31%29%5%
894
11th to 20thNight
22%12%32%27%7%
805
21st to endNight
25%13%32%26%4
792
February1st to 10thNight
20%12%32%31%4
720
11th to 20thNight
23%16%29%26%6%
703
21st to endNight
23%17%38%20%3
592
March1st to 10thNight
17%16%31%29%7%
720
11th to 20thNight
16%12%34%28%9%
576
21st to endNight
15%11%34%28%11%1
594
April1st to 10thNight
17%9%32%29%13%1
540
11th to 20thNight
15%8%33%28%14%1
533
21st to endNight
8%6%30%40%15%1
540
May1st to 10thNight
9%428%39%19%2
540
11th to 20thNight
10%418%42%22%5%
531
21st to endNight
7%214%34%36%7%
584
June1st to 10thNight
10%212%33%37%6%
540
11th to 20thNight
419%31%44%11%
540
21st to endNight
7%210%26%43%12%
540
July1st to 10thNight
5%1424%49%17%
525
11th to 20thNight
7%15%19%46%22%
522
21st to endNight
5%424%49%18%
591
August1st to 10thNight
4420%49%23%
537
11th to 20thNight
9%5%20%45%21%
534
21st to endNight
10%17%18%44%21%
594
September1st to 10thNight
10%27%27%42%12%
540
11th to 20thNight
9%210%29%41%9%
622
21st to endNight
12%213%30%38%6%
720
October1st to 10thNight
9%317%31%36%4
720
11th to 20thNight
11%5%19%33%28%3
720
21st to endNight
17%6%19%32%23%2
792
November1st to 10thNight
12%7%18%40%20%3
740
11th to 20thNight
16%8%26%33%16%1
760
21st to endNight
16%9%26%31%17%2
760
December1st to 10thNight
21%11%27%29%12%
760
11th to 20thNight
22%8%33%27%10%
760
21st to endNight
27%11%28%28%6%
836
Page generated at 2024-01-11 12:32:00. Version ac07

Copyright 2024 Attilla Danko


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