Luckey
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Luckey clear sky chart from 2005-11-06 to 2024-01-27.

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
37%
24341
16%
74700
11%
24284
43%
24284
21%
51780

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
18%
949
13%
2648
4%
946
26%
946
13%
2057
January11th to 20thNight
15%
899
9%
2609
4%
899
20%
899
11%
2101
January21st to endNight
18%
820
10%
2664
5%
820
25%
820
11%
2083
February1st to 10thNight
18%
720
8%
2340
3%
720
23%
720
11%
1812
February11th to 20thNight
21%
701
14%
2117
7%
700
29%
700
14%
1580
February21st to endNight
15%
592
15%
1776
4%
592
25%
592
14%
1319
March1st to 10thNight
26%
720
15%
2117
8%
720
32%
720
17%
1535
March11th to 20thNight
28%
720
20%
1980
10%
720
37%
720
23%
1354
March21st to endNight
31%
792
18%
2178
10%
792
37%
792
20%
1561
April1st to 10thNight
27%
630
14%
1890
6%
630
35%
630
20%
1286
April11th to 20thNight
32%
533
21%
1647
11%
533
41%
533
21%
1104
April21st to endNight
33%
540
18%
1620
6%
540
43%
540
24%
1097
May1st to 10thNight
36%
540
12%
1620
6%
540
42%
540
19%
1177
May11th to 20thNight
40%
531
18%
1592
11%
531
46%
531
22%
1074
May21st to endNight
54%
583
16%
1745
13%
582
58%
582
31%
1083
June1st to 10thNight
52%
540
16%
1525
12%
540
57%
540
32%
957
June11th to 20thNight
56%
540
19%
1440
15%
540
60%
540
33%
907
June21st to endNight
56%
540
20%
1440
15%
540
62%
540
35%
895
July1st to 10thNight
65%
525
17%
1400
15%
525
66%
525
37%
861
July11th to 20thNight
63%
522
21%
1406
17%
522
66%
522
40%
832
July21st to endNight
67%
591
19%
1672
16%
558
70%
558
38%
963
August1st to 10thNight
67%
537
21%
1600
18%
534
69%
534
37%
919
August11th to 20thNight
66%
534
23%
1598
19%
534
69%
534
35%
946
August21st to endNight
64%
594
22%
1830
19%
594
67%
594
34%
1067
September1st to 10thNight
61%
652
21%
1912
18%
652
64%
652
31%
1167
September11th to 20thNight
62%
720
30%
1980
22%
720
65%
720
38%
1166
September21st to endNight
50%
720
24%
1980
18%
720
55%
720
31%
1271
October1st to 10thNight
50%
720
22%
2016
17%
720
54%
720
31%
1261
October11th to 20thNight
33%
720
18%
2160
12%
720
42%
720
22%
1452
October21st to endNight
29%
792
18%
2500
13%
792
37%
792
18%
1722
November1st to 10thNight
36%
740
21%
2406
17%
740
44%
740
25%
1501
November11th to 20thNight
25%
760
19%
2470
11%
760
36%
760
18%
1680
November21st to endNight
25%
760
14%
2470
10%
760
31%
760
14%
1820
December1st to 10thNight
20%
760
10%
2470
5%
760
26%
760
12%
1881
December11th to 20thNight
19%
763
11%
3012
4%
762
28%
762
11%
2222
December21st to endNight
16%
1041
4%
4870
2%
1026
21%
1026
5%
4067

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%9%47%6%35%5%5%7%34%
75109
Night
16%9%47%6%3445%7%35%
74944
TransparencyDay
49%5%11%21%12%2
74822
Night
49%411%21%12%2
74751
SeeingDay
18%10%27%24%15%6%
14426
Night
19%9%28%29%13%1
24350

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%15%5%10%9%45%5%5%5%19%
1517
11th to 20thDay
17%19%8%10%8%5%6%44416%
1567
21st to endDay
17%17%8%11%8%44346%18%
1836
February1st to 10thDay
17%15%6%10%8%5%6%5%45%20%
1620
11th to 20thDay
16%11%5%10%10%46%5%46%23%
1726
21st to endDay
18%12%5%8%6%36%45%6%26%
1480
March1st to 10thDay
17%12%6%9%7%345%6%5%26%
1842
11th to 20thDay
16%11%5%8%6%345%46%32%
1980
21st to endDay
22%11%5%8%6%35%446%25%
2178
April1st to 10thDay
13%11%5%8%7%46%6%5%6%30%
2083
11th to 20thDay
18%7%46%6%45%5%6%7%34%
2262
21st to endDay
20%8%36%5%3445%6%35%
2340
May1st to 10thDay
17%8%37%7%45%5%6%7%31%
2340
11th to 20thDay
17%8%37%6%35%5%5%6%34%
2301
21st to endDay
11%5%26%7%46%6%6%9%39%
2531
June1st to 10thDay
12%6%25%6%5%5%6%6%7%39%
2430
11th to 20thDay
10%6%25%6%45%5%5%9%42%
2520
21st to endDay
10%6%36%6%45%6%7%9%38%
2520
July1st to 10thDay
8%6%35%5%36%5%6%9%45%
2520
11th to 20thDay
8%425%6%36%6%8%10%42%
2502
21st to endDay
9%5%35%6%36%6%6%9%42%
2547
August1st to 10thDay
8%415%5%36%6%7%9%45%
2327
11th to 20thDay
9%5%25%6%46%6%8%11%39%
2303
21st to endDay
10%5%245%35%5%7%9%44%
2522
September1st to 10thDay
14%6%25%6%25%5%5%9%43%
2028
11th to 20thDay
9%5%25%5%35%5%6%9%46%
1980
21st to endDay
16%6%35%335%5%5%7%43%
1980
October1st to 10thDay
13%7%25%5%45%46%8%41%
1944
11th to 20thDay
18%7%36%6%3445%7%37%
1800
21st to endDay
20%8%36%7%35%5%6%7%30%
1854
November1st to 10thDay
12%9%35%5%345%6%7%42%
1672
11th to 20thDay
17%11%47%5%34446%34%
1710
21st to endDay
19%13%5%8%5%345%5%7%28%
1710
December1st to 10thDay
17%17%8%11%6%45%435%20%
1710
11th to 20thDay
15%14%6%10%7%46%5%46%24%
2144
21st to endDay
23%20%7%11%7%4443412%
2783
January1st to 10thNight
18%13%6%9%6%45%45%5%25%
2648
11th to 20thNight
19%15%6%10%7%45%445%21%
2609
21st to endNight
17%16%6%11%7%34445%23%
2664
February1st to 10thNight
19%13%6%9%7%445%5%5%23%
2340
11th to 20thNight
15%14%5%8%6%45%45%6%26%
2116
21st to endNight
21%12%5%7%6%35%45%5%28%
1776
March1st to 10thNight
16%10%48%7%45%35%5%33%
2117
11th to 20thNight
15%8%35%6%3445%7%39%
1980
21st to endNight
20%10%46%6%34446%34%
2178
April1st to 10thNight
16%9%47%5%45%5%5%7%35%
1890
11th to 20thNight
17%8%25%6%35%45%7%37%
1647
21st to endNight
17%8%35%5%35%5%5%7%38%
1620
May1st to 10thNight
18%8%47%6%45%5%5%7%31%
1620
11th to 20thNight
19%6%36%5%25%45%7%38%
1592
21st to endNight
10%436%5%45%5%6%10%42%
1744
June1st to 10thNight
11%5%25%6%26%5%6%7%45%
1525
11th to 20thNight
10%5%25%5%335%8%8%45%
1440
21st to endNight
10%424435%5%7%10%46%
1440
July1st to 10thNight
9%415%5%3345%9%50%
1440
11th to 20thNight
8%4244345%7%8%50%
1454
21st to endNight
7%424435%6%6%10%49%
1771
August1st to 10thNight
6%325%6%245%6%9%51%
1611
11th to 20thNight
8%4246%35%6%5%9%48%
1598
21st to endNight
8%4246%35%5%5%8%50%
1830
September1st to 10thNight
11%6%25%5%2446%7%48%
1912
11th to 20thNight
9%5%34433347%53%
1980
21st to endNight
13%5%36%5%3445%6%46%
1980
October1st to 10thNight
13%6%25%5%3445%7%46%
2016
11th to 20thNight
18%8%36%5%3445%6%38%
2160
21st to endNight
21%8%36%5%3445%6%35%
2500
November1st to 10thNight
13%8%36%5%35%45%6%43%
2406
11th to 20thNight
16%10%47%6%345%5%7%33%
2470
21st to endNight
20%13%47%6%45%446%27%
2470
December1st to 10thNight
18%12%6%9%6%5%5%45%7%23%
2470
11th to 20thNight
16%15%6%8%6%35%5%5%6%26%
3046
21st to endNight
26%19%7%9%7%34445%12%
4884

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
67%5%11%13%4
1518
11th to 20thDay
72%411%9%4
1567
21st to endDay
70%49%12%5%1
1836
February1st to 10thDay
66%410%13%6%
1620
11th to 20thDay
62%5%9%16%7%1
1736
21st to endDay
58%314%15%7%2
1480
March1st to 10thDay
59%411%19%6%
1842
11th to 20thDay
54%411%19%10%2
1980
21st to endDay
61%48%21%6%1
2178
April1st to 10thDay
53%5%11%19%12%1
2083
11th to 20thDay
49%5%12%20%13%2
2262
21st to endDay
50%5%11%22%11%2
2340
May1st to 10thDay
51%5%11%20%12%1
2340
11th to 20thDay
51%5%10%19%14%2
2305
21st to endDay
41%6%13%25%12%2
2531
June1st to 10thDay
41%5%11%26%13%3
2430
11th to 20thDay
39%5%13%22%18%2
2520
21st to endDay
40%6%13%21%15%4
2520
July1st to 10thDay
37%6%11%25%19%3
2451
11th to 20thDay
33%6%13%28%17%3
2427
21st to endDay
37%6%12%24%18%2
2405
August1st to 10thDay
32%7%14%30%16%
2314
11th to 20thDay
37%7%15%26%13%2
2303
21st to endDay
35%6%12%25%19%3
2522
September1st to 10thDay
40%5%12%23%16%3
2028
11th to 20thDay
35%412%29%19%1
1980
21st to endDay
41%412%25%17%1
1980
October1st to 10thDay
42%5%10%27%14%2
1944
11th to 20thDay
47%311%23%15%1
1800
21st to endDay
52%5%12%20%11%1
1854
November1st to 10thDay
42%5%11%25%17%1
1672
11th to 20thDay
52%411%20%12%1
1710
21st to endDay
56%412%20%8%
1710
December1st to 10thDay
69%410%14%4
1710
11th to 20thDay
62%412%18%5%
2141
21st to endDay
77%38%8%3
2783
January1st to 10thNight
62%49%17%8%
2648
11th to 20thNight
67%312%14%4
2609
21st to endNight
65%410%15%6%1
2664
February1st to 10thNight
63%5%11%15%5%1
2340
11th to 20thNight
58%49%19%8%1
2117
21st to endNight
58%411%17%9%2
1776
March1st to 10thNight
54%410%21%10%1
2117
11th to 20thNight
45%5%11%20%16%2
1980
21st to endNight
52%48%25%10%2
2178
April1st to 10thNight
48%411%20%14%2
1890
11th to 20thNight
47%49%20%17%2
1647
21st to endNight
46%5%10%22%14%3
1620
May1st to 10thNight
53%5%11%17%12%2
1620
11th to 20thNight
46%6%8%21%17%2
1593
21st to endNight
37%6%12%28%15%3
1745
June1st to 10thNight
38%411%27%16%3
1525
11th to 20thNight
35%7%13%27%17%3
1440
21st to endNight
33%7%14%27%18%2
1440
July1st to 10thNight
34%5%12%24%21%4
1400
11th to 20thNight
30%5%15%28%20%2
1406
21st to endNight
29%7%16%26%19%4
1672
August1st to 10thNight
30%6%13%32%17%1
1600
11th to 20thNight
32%6%15%29%16%2
1598
21st to endNight
32%6%13%24%22%3
1830
September1st to 10thNight
36%5%12%25%17%5%
1912
11th to 20thNight
32%410%28%25%1
1980
21st to endNight
39%5%10%24%20%2
1980
October1st to 10thNight
39%411%25%20%1
2016
11th to 20thNight
47%410%23%16%1
2160
21st to endNight
50%49%24%11%2
2500
November1st to 10thNight
42%411%25%17%2
2406
11th to 20thNight
50%411%22%11%1
2470
21st to endNight
58%412%19%7%
2470
December1st to 10thNight
61%412%16%7%
2470
11th to 20thNight
59%5%13%16%6%1
3048
21st to endNight
75%311%8%3
4884

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
23%21%29%20%6%1
270
11th to 20thDay
23%18%40%13%6%1
270
21st to endDay
29%13%33%20%5%1
282
February1st to 10thDay
30%16%40%13%1
240
11th to 20thDay
24%18%40%15%3
240
21st to endDay
27%19%42%10%2
198
March1st to 10thDay
22%16%38%19%5%1
282
11th to 20thDay
22%12%38%20%6%2
420
21st to endDay
31%13%31%18%7%
462
April1st to 10thDay
20%13%31%21%13%1
420
11th to 20thDay
20%17%29%21%9%4
412
21st to endDay
26%12%30%22%9%2
420
May1st to 10thDay
24%9%31%20%13%3
423
11th to 20thDay
20%11%27%23%12%7%
447
21st to endDay
14%6%24%26%18%11%
485
June1st to 10thDay
12%5%26%34%17%5%
540
11th to 20thDay
13%7%27%27%20%5%
630
21st to endDay
13%7%26%30%18%6%
630
July1st to 10thDay
9%419%34%20%14%
621
11th to 20thDay
9%422%32%21%12%
600
21st to endDay
10%420%27%25%13%
488
August1st to 10thDay
11%213%30%28%16%
446
11th to 20thDay
14%315%30%24%14%
439
21st to endDay
11%318%26%28%15%
495
September1st to 10thDay
16%415%28%25%12%
450
11th to 20thDay
10%314%27%30%16%
450
21st to endDay
17%8%22%24%19%10%
450
October1st to 10thDay
14%7%25%26%20%9%
450
11th to 20thDay
18%16%30%24%9%2
450
21st to endDay
25%11%35%22%5%1
369
November1st to 10thDay
14%14%33%23%13%4
270
11th to 20thDay
24%16%30%20%8%1
270
21st to endDay
25%13%36%24%2
270
December1st to 10thDay
22%19%33%18%8%
270
11th to 20thDay
19%21%35%20%4
270
21st to endDay
27%17%33%20%4
297
January1st to 10thNight
24%14%35%21%6%
950
11th to 20thNight
28%13%35%18%5%1
899
21st to endNight
24%13%35%23%5%
820
February1st to 10thNight
28%12%34%23%3
720
11th to 20thNight
23%13%34%26%3
703
21st to endNight
27%15%37%19%2
592
March1st to 10thNight
21%11%33%27%7%
720
11th to 20thNight
19%13%35%26%7%1
720
21st to endNight
24%11%29%27%9%
792
April1st to 10thNight
20%13%35%27%41
630
11th to 20thNight
22%9%32%27%9%1
533
21st to endNight
21%7%33%28%9%1
540
May1st to 10thNight
21%6%29%34%9%1
540
11th to 20thNight
21%5%27%31%15%2
531
21st to endNight
11%224%38%22%3
584
June1st to 10thNight
12%5%21%44%18%
540
11th to 20thNight
12%420%45%18%1
540
21st to endNight
12%123%41%21%2
540
July1st to 10thNight
11%114%40%30%4
525
11th to 20thNight
10%318%40%25%5%
522
21st to endNight
8%214%42%32%2
591
August1st to 10thNight
8%111%43%32%4
537
11th to 20thNight
9%115%35%35%5%
534
21st to endNight
9%213%37%34%4
594
September1st to 10thNight
15%5%13%34%28%6%
652
11th to 20thNight
11%314%34%33%4
720
21st to endNight
14%5%21%33%23%3
720
October1st to 10thNight
15%6%23%32%21%2
720
11th to 20thNight
20%12%29%28%9%2
720
21st to endNight
25%12%29%27%7%
792
November1st to 10thNight
16%11%31%29%11%2
740
11th to 20thNight
23%15%31%23%8%1
760
21st to endNight
26%12%32%24%6%1
760
December1st to 10thNight
24%14%34%22%5%
760
11th to 20thNight
26%12%35%23%4
764
21st to endNight
30%13%32%22%3
1045
Page generated at 2024-01-24 09:37:27. Version ac07

Copyright 2024 Attilla Danko


Luckey Clear Sky Chart |Charts Home