Jackson
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jackson clear sky chart from 2005-11-06 to 2024-02-15.

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
46%
24177
23%
79842
17%
24068
53%
24068
27%
48686

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
24%
942
21%
4324
9%
926
35%
926
15%
2701
January11th to 20thNight
20%
949
22%
4053
7%
930
30%
930
13%
2581
January21st to endNight
23%
1003
17%
4388
8%
986
36%
986
16%
2770
February1st to 10thNight
22%
760
19%
2280
7%
760
33%
760
19%
1589
February11th to 20thNight
21%
722
19%
2153
9%
718
29%
718
19%
1456
February21st to endNight
22%
592
20%
1776
9%
592
31%
592
19%
1215
March1st to 10thNight
31%
720
21%
2160
10%
720
39%
720
25%
1387
March11th to 20thNight
27%
640
17%
2080
10%
640
35%
640
20%
1378
March21st to endNight
35%
594
20%
1990
12%
594
44%
594
22%
1275
April1st to 10thNight
36%
540
25%
1800
15%
540
49%
540
29%
1055
April11th to 20thNight
39%
533
26%
1775
18%
533
53%
533
29%
1037
April21st to endNight
39%
540
23%
1800
16%
540
51%
540
29%
1061
May1st to 10thNight
48%
540
22%
1742
17%
540
54%
540
31%
1032
May11th to 20thNight
51%
531
20%
1592
15%
531
54%
531
28%
1000
May21st to endNight
65%
583
19%
1704
16%
582
67%
582
32%
1038
June1st to 10thNight
64%
540
22%
1440
17%
540
66%
540
32%
941
June11th to 20thNight
78%
540
29%
1440
24%
540
79%
540
51%
774
June21st to endNight
78%
540
26%
1440
20%
540
80%
540
46%
818
July1st to 10thNight
75%
525
17%
1400
16%
525
75%
525
33%
912
July11th to 20thNight
75%
522
22%
1392
19%
522
76%
522
39%
841
July21st to endNight
79%
591
23%
1677
24%
558
79%
558
41%
935
August1st to 10thNight
77%
537
22%
1778
25%
534
78%
534
35%
977
August11th to 20thNight
75%
534
22%
1776
26%
534
76%
534
34%
1002
August21st to endNight
75%
594
24%
1980
30%
594
76%
594
34%
1110
September1st to 10thNight
72%
540
27%
1800
31%
540
74%
540
33%
1007
September11th to 20thNight
68%
630
28%
1890
26%
630
70%
630
36%
1091
September21st to endNight
66%
720
32%
1980
24%
720
70%
720
44%
1105
October1st to 10thNight
65%
720
33%
1994
27%
720
68%
720
45%
1093
October11th to 20thNight
52%
720
31%
2160
23%
720
61%
720
36%
1219
October21st to endNight
43%
792
29%
2420
20%
792
52%
792
30%
1474
November1st to 10thNight
50%
740
30%
2406
25%
740
60%
740
36%
1294
November11th to 20thNight
41%
760
29%
2470
20%
760
54%
760
33%
1377
November21st to endNight
38%
760
25%
2470
19%
760
48%
760
26%
1507
December1st to 10thNight
29%
760
22%
2470
12%
760
41%
760
21%
1617
December11th to 20thNight
34%
882
25%
3063
14%
881
45%
881
22%
1864
December21st to endNight
25%
1041
12%
4779
9%
1026
35%
1026
13%
3153

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
12%7%35%5%35%5%5%8%43%
78488
Night
13%6%25%5%3445%7%46%
80629
TransparencyDay
40%6%11%22%18%3
78203
Night
38%6%10%23%20%5%
80435
SeeingDay
15%9%22%24%21%9%
14261
Night
16%8%24%30%19%3
24197

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
13%13%37%5%33345%41%
2527
11th to 20thDay
20%8%35%434235%43%
2764
21st to endDay
22%10%34433445%38%
3193
February1st to 10thDay
19%10%37%5%33336%38%
1900
11th to 20thDay
20%9%36%5%34335%38%
1788
21st to endDay
21%10%36%6%3335%5%34%
1480
March1st to 10thDay
15%9%36%5%34446%42%
1800
11th to 20thDay
19%9%46%5%35%45%6%34%
1894
21st to endDay
17%9%46%7%35%45%6%36%
2364
April1st to 10thDay
12%7%35%5%3445%7%46%
2160
11th to 20thDay
16%6%35%5%23346%45%
2134
21st to endDay
13%6%27%5%445%5%7%42%
2160
May1st to 10thDay
14%6%35%6%245%6%7%42%
2218
11th to 20thDay
12%6%26%6%45%46%8%41%
2301
21st to endDay
7%6%36%6%47%6%8%10%37%
2567
June1st to 10thDay
8%5%36%5%45%5%7%10%42%
2520
11th to 20thDay
43245%46%6%7%10%50%
2520
21st to endDay
5%324436%7%7%12%46%
2520
July1st to 10thDay
6%5%35%7%47%6%9%11%37%
2520
11th to 20thDay
7%5%35%6%45%6%7%12%39%
2520
21st to endDay
7%4246%46%7%8%10%42%
2535
August1st to 10thDay
5%5%25%6%5%6%7%9%11%40%
2148
11th to 20thDay
9%5%26%6%45%6%8%10%39%
2125
21st to endDay
9%6%35%6%45%47%9%43%
2376
September1st to 10thDay
8%5%36%5%35%5%6%8%46%
2160
11th to 20thDay
12%425%435%5%6%8%45%
2052
21st to endDay
10%5%24424447%52%
1980
October1st to 10thDay
9%32442346%6%58%
1962
11th to 20thDay
11%5%25%32445%6%54%
1800
21st to endDay
18%6%2342334450%
1935
November1st to 10thDay
10%6%2432235%6%58%
1672
11th to 20thDay
14%5%35%323346%52%
1710
21st to endDay
17%7%3342445%7%44%
1710
December1st to 10thDay
20%8%36%43435%5%39%
1710
11th to 20thDay
14%9%36%6%34446%42%
1980
21st to endDay
13%12%47%5%45%5%5%5%35%
2783
January1st to 10thNight
19%10%24424435%42%
4428
11th to 20thNight
17%9%47%5%3433442%
4202
21st to endNight
25%9%24323335%41%
4469
February1st to 10thNight
20%10%45%5%24435%37%
2280
11th to 20thNight
20%8%35%5%34335%40%
2153
21st to endNight
21%7%26%5%3445%5%38%
1776
March1st to 10thNight
16%7%35%5%2446%6%44%
2160
11th to 20thNight
19%8%36%5%2345%6%39%
2080
21st to endNight
14%7%25%6%345%6%7%41%
1990
April1st to 10thNight
11%6%35%5%3345%8%48%
1800
11th to 20thNight
15%6%2442345%8%47%
1775
21st to endNight
10%6%35%6%25%5%5%8%46%
1800
May1st to 10thNight
13%5%35%32445%8%48%
1742
11th to 20thNight
10%5%36%6%35%46%8%45%
1592
21st to endNight
5%4345%5%5%6%8%12%44%
1704
June1st to 10thNight
7%6%36%6%35%5%6%10%42%
1440
11th to 20thNight
331333448%10%58%
1440
21st to endNight
3213435%5%7%13%54%
1440
July1st to 10thNight
4417%5%37%7%9%10%43%
1440
11th to 20thNight
6%424435%5%7%13%47%
1440
21st to endNight
43235%25%5%6%12%54%
1776
August1st to 10thNight
3415%6%45%6%7%10%50%
1790
11th to 20thNight
5%325%5%35%7%7%10%49%
1776
21st to endNight
6%425%5%346%7%9%49%
1980
September1st to 10thNight
8%416%5%235%6%7%53%
1800
11th to 20thNight
7%5%25%6%245%5%7%52%
1890
21st to endNight
9%424423347%59%
1980
October1st to 10thNight
8%32432345%6%60%
1994
11th to 20thNight
12%5%24324446%56%
2160
21st to endNight
17%6%24423445%49%
2420
November1st to 10thNight
11%5%24332346%57%
2406
11th to 20thNight
10%5%2442445%7%52%
2470
21st to endNight
16%7%25%434345%48%
2470
December1st to 10thNight
19%9%35%5%23445%41%
2470
11th to 20thNight
15%8%35%433445%47%
3212
21st to endNight
15%10%47%6%45%5%5%6%33%
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
47%46%22%19%2
2528
11th to 20thDay
46%6%7%20%21%1
2764
21st to endDay
49%37%21%17%2
3193
February1st to 10thDay
49%38%21%17%2
1900
11th to 20thDay
50%47%19%16%4
1798
21st to endDay
52%48%15%14%7%
1480
March1st to 10thDay
45%5%7%17%20%7%
1800
11th to 20thDay
51%5%8%18%15%3
1894
21st to endDay
50%5%9%21%14%1
2364
April1st to 10thDay
38%5%9%23%21%3
2160
11th to 20thDay
42%47%21%20%6%
2134
21st to endDay
41%6%10%24%18%1
2160
May1st to 10thDay
40%7%12%23%17%2
2218
11th to 20thDay
40%9%12%22%16%1
2305
21st to endDay
38%11%13%25%11%2
2567
June1st to 10thDay
36%9%13%21%19%2
2520
11th to 20thDay
26%8%15%29%18%4
2520
21st to endDay
28%10%16%25%18%4
2520
July1st to 10thDay
36%12%17%20%13%3
2451
11th to 20thDay
35%10%18%22%12%4
2445
21st to endDay
33%10%15%29%12%1
2394
August1st to 10thDay
33%11%17%26%12%1
2136
11th to 20thDay
36%9%14%22%16%2
2125
21st to endDay
36%7%14%23%16%3
2376
September1st to 10thDay
34%9%10%26%18%4
2160
11th to 20thDay
37%7%9%19%23%4
2052
21st to endDay
32%5%10%22%24%7%
1980
October1st to 10thDay
27%5%11%25%25%6%
1962
11th to 20thDay
31%47%22%28%8%
1800
21st to endDay
38%46%20%25%6%
1935
November1st to 10thDay
29%38%24%28%7%
1672
11th to 20thDay
36%37%21%25%8%
1710
21st to endDay
41%47%21%22%5%
1710
December1st to 10thDay
47%5%7%22%15%4
1710
11th to 20thDay
45%48%21%19%3
1977
21st to endDay
49%5%10%21%13%1
2783
January1st to 10thNight
45%5%6%22%20%2
4428
11th to 20thNight
47%5%6%20%18%4
4202
21st to endNight
47%37%23%17%3
4469
February1st to 10thNight
51%49%16%18%3
2280
11th to 20thNight
48%47%20%17%4
2154
21st to endNight
48%5%8%17%16%6%
1776
March1st to 10thNight
41%5%7%17%21%9%
2160
11th to 20thNight
46%5%9%19%17%3
2080
21st to endNight
42%6%10%21%17%2
1990
April1st to 10thNight
35%6%11%24%19%5%
1800
11th to 20thNight
36%48%21%23%8%
1775
21st to endNight
36%5%11%26%19%3
1800
May1st to 10thNight
35%6%10%25%20%4
1742
11th to 20thNight
36%8%14%23%17%2
1593
21st to endNight
31%10%15%28%14%2
1705
June1st to 10thNight
35%9%11%21%22%2
1440
11th to 20thNight
20%6%16%33%21%4
1440
21st to endNight
21%9%17%29%19%5%
1440
July1st to 10thNight
30%13%17%23%13%3
1400
11th to 20thNight
27%9%19%25%12%7%
1392
21st to endNight
24%9%20%32%15%1
1677
August1st to 10thNight
27%9%15%32%16%1
1778
11th to 20thNight
26%11%18%26%16%3
1776
21st to endNight
29%8%15%28%15%6%
1980
September1st to 10thNight
29%8%10%25%21%6%
1800
11th to 20thNight
30%7%12%18%29%5%
1890
21st to endNight
27%48%28%26%7%
1980
October1st to 10thNight
24%5%9%24%26%11%
1994
11th to 20thNight
31%47%21%28%9%
2160
21st to endNight
38%45%21%24%8%
2420
November1st to 10thNight
29%46%24%29%8%
2406
11th to 20thNight
32%47%22%24%11%
2470
21st to endNight
40%46%21%24%5%
2470
December1st to 10thNight
46%48%20%18%4
2470
11th to 20thNight
40%36%24%22%5%
3214
21st to endNight
48%6%10%19%13%4
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
25%19%36%16%4
270
11th to 20thDay
29%18%37%12%31
270
21st to endDay
22%22%40%11%4
297
February1st to 10thDay
25%21%33%15%5%1
270
11th to 20thDay
36%21%33%8%2
252
21st to endDay
34%21%32%9%4
198
March1st to 10thDay
24%20%37%14%5%
240
11th to 20thDay
28%20%36%13%2
240
21st to endDay
24%18%31%19%8%
450
April1st to 10thDay
17%15%34%24%9%1
420
11th to 20thDay
22%13%29%25%11%1
412
21st to endDay
19%15%27%24%12%2
420
May1st to 10thDay
21%12%26%26%11%3
423
11th to 20thDay
15%5%25%27%19%9%
447
21st to endDay
11%320%30%23%13%
521
June1st to 10thDay
10%417%28%26%16%
630
11th to 20thDay
4214%32%33%15%
630
21st to endDay
7%217%34%28%13%
630
July1st to 10thDay
7%212%26%32%21%
621
11th to 20thDay
8%211%22%37%20%
618
21st to endDay
5%210%27%35%21%
626
August1st to 10thDay
8%38%29%35%17%
446
11th to 20thDay
10%113%30%35%11%
439
21st to endDay
11%18%20%39%21%
495
September1st to 10thDay
7%311%27%38%14%
450
11th to 20thDay
10%311%24%34%18%
450
21st to endDay
16%5%13%30%24%12%
450
October1st to 10thDay
9%419%31%28%9%
432
11th to 20thDay
10%14%38%27%10%1
270
21st to endDay
22%14%30%21%10%2
297
November1st to 10thDay
16%7%30%33%12%2
270
11th to 20thDay
11%16%35%29%7%1
270
21st to endDay
26%11%29%20%11%2
270
December1st to 10thDay
27%19%29%18%7%1
270
11th to 20thDay
22%19%31%19%9%
270
21st to endDay
27%18%37%15%4
297
January1st to 10thNight
23%15%34%24%5%
950
11th to 20thNight
24%17%33%21%4
950
21st to endNight
23%12%39%24%2
1008
February1st to 10thNight
25%14%34%22%4
760
11th to 20thNight
26%18%33%21%2
722
21st to endNight
25%18%34%21%2
592
March1st to 10thNight
20%13%33%29%5%
720
11th to 20thNight
25%11%35%25%5%1
640
21st to endNight
18%11%32%29%9%
594
April1st to 10thNight
14%11%36%30%9%1
540
11th to 20thNight
17%9%31%31%11%1
533
21st to endNight
12%8%35%31%12%2
540
May1st to 10thNight
15%7%26%37%14%1
540
11th to 20thNight
11%5%24%36%20%4
531
21st to endNight
8%218%37%31%5%
584
June1st to 10thNight
11%212%39%30%6%
540
11th to 20thNight
4111%37%43%4
540
21st to endNight
4111%39%38%7%
540
July1st to 10thNight
6%27%32%42%11%
525
11th to 20thNight
7%19%25%46%13%
522
21st to endNight
5%17%28%46%12%
591
August1st to 10thNight
5%6%31%49%8%
537
11th to 20thNight
7%16%39%42%6%
534
21st to endNight
8%16%30%44%10%
594
September1st to 10thNight
9%17%34%44%5%
540
11th to 20thNight
8%212%32%40%7%
630
21st to endNight
11%214%36%32%5%
720
October1st to 10thNight
9%417%36%30%4
720
11th to 20thNight
15%6%23%36%18%2
720
21st to endNight
20%7%28%30%14%1
792
November1st to 10thNight
14%7%26%34%17%2
740
11th to 20thNight
12%10%33%34%10%1
760
21st to endNight
19%10%29%29%12%1
760
December1st to 10thNight
25%11%30%27%7%
760
11th to 20thNight
21%12%29%31%7%
883
21st to endNight
25%15%31%25%5%
1045
Page generated at 2024-02-12 05:35:33. Version ac07

Copyright 2024 Attilla Danko


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