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 2024-02-20.

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
35%
24644
14%
80535
10%
24536
41%
24536
18%
57509

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
16%
944
10%
4394
4%
926
23%
926
7%
3407
January11th to 20thNight
16%
947
6%
4416
3%
930
20%
930
6%
3632
January21st to endNight
18%
939
4%
4699
3%
919
22%
919
6%
3956
February1st to 10thNight
17%
760
8%
2457
4%
760
22%
760
10%
1956
February11th to 20thNight
19%
739
13%
2214
6%
739
25%
739
13%
1661
February21st to endNight
15%
592
14%
1776
3%
592
25%
592
14%
1310
March1st to 10thNight
25%
720
15%
2160
9%
720
31%
720
18%
1521
March11th to 20thNight
28%
720
19%
1981
8%
720
37%
720
21%
1366
March21st to endNight
28%
792
17%
2178
9%
792
34%
792
19%
1580
April1st to 10thNight
25%
562
15%
1822
8%
562
34%
562
19%
1238
April11th to 20thNight
31%
533
19%
1678
10%
533
41%
533
21%
1140
April21st to endNight
33%
540
16%
1620
7%
540
40%
540
22%
1096
May1st to 10thNight
35%
540
13%
1620
8%
540
39%
540
19%
1159
May11th to 20thNight
39%
531
17%
1593
10%
531
46%
531
23%
1085
May21st to endNight
54%
583
14%
1684
11%
582
57%
582
30%
1062
June1st to 10thNight
55%
540
16%
1440
12%
540
60%
540
37%
897
June11th to 20thNight
53%
540
17%
1440
13%
540
56%
540
32%
934
June21st to endNight
58%
540
19%
1440
13%
540
63%
540
36%
894
July1st to 10thNight
66%
525
17%
1400
15%
525
68%
525
39%
836
July11th to 20thNight
65%
522
21%
1392
18%
522
67%
522
39%
838
July21st to endNight
66%
591
20%
1572
15%
558
70%
558
39%
916
August1st to 10thNight
68%
537
21%
1600
18%
534
70%
534
36%
931
August11th to 20thNight
67%
534
22%
1598
18%
534
70%
534
34%
956
August21st to endNight
63%
594
23%
1876
20%
594
67%
594
34%
1089
September1st to 10thNight
59%
607
22%
1867
19%
607
62%
607
30%
1139
September11th to 20thNight
63%
720
29%
1980
24%
720
65%
720
37%
1195
September21st to endNight
50%
720
22%
1980
16%
720
55%
720
30%
1284
October1st to 10thNight
46%
720
21%
1984
16%
720
50%
720
29%
1286
October11th to 20thNight
30%
720
16%
2160
9%
720
39%
720
18%
1519
October21st to endNight
24%
792
16%
2574
9%
792
34%
792
16%
1824
November1st to 10thNight
33%
740
19%
2406
15%
740
40%
740
21%
1571
November11th to 20thNight
24%
760
15%
2470
9%
760
32%
760
16%
1746
November21st to endNight
25%
760
14%
2470
9%
760
32%
760
14%
1819
December1st to 10thNight
17%
760
8%
2470
5%
760
21%
760
9%
1980
December11th to 20thNight
17%
940
9%
3246
2%
938
24%
938
10%
2535
December21st to endNight
13%
1040
4%
4878
2%
1026
19%
1026
4%
4151

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%10%47%6%45%5%5%7%32%
78408
Night
16%11%5%7%6%3445%6%33%
80826
TransparencyDay
50%7%12%19%11%1
78116
Night
51%7%12%19%11%1
80640
SeeingDay
17%11%29%23%14%6%
14654
Night
19%9%30%29%12%1
24664

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
17%17%7%9%7%45%5%45%20%
2527
11th to 20thDay
16%16%7%11%9%5%7%8%5%5%12%
2530
21st to endDay
27%19%9%11%6%3322414%
2943
February1st to 10thDay
14%14%7%9%10%47%5%47%20%
1719
11th to 20thDay
15%9%7%12%8%5%5%5%45%24%
1838
21st to endDay
17%14%7%10%6%45%45%5%23%
1480
March1st to 10thDay
14%10%5%8%7%5%6%6%6%7%26%
1800
11th to 20thDay
14%11%47%6%3445%7%34%
1979
21st to endDay
19%13%47%6%35%45%7%28%
2178
April1st to 10thDay
18%13%48%5%44446%30%
2153
11th to 20thDay
17%10%36%5%35%46%7%35%
2230
21st to endDay
18%8%47%6%35%45%7%33%
2340
May1st to 10thDay
17%8%45%7%35%5%6%7%33%
2340
11th to 20thDay
19%8%36%5%4445%7%34%
2301
21st to endDay
12%6%25%5%36%5%7%9%40%
2589
June1st to 10thDay
11%6%25%6%45%5%7%9%42%
2520
11th to 20thDay
11%5%25%5%35%6%6%9%41%
2520
21st to endDay
9%5%26%6%46%7%7%10%39%
2520
July1st to 10thDay
7%4246%45%7%7%9%45%
2520
11th to 20thDay
10%5%25%5%35%5%6%9%44%
2520
21st to endDay
7%5%245%46%6%7%10%42%
2653
August1st to 10thDay
8%425%6%37%6%7%10%42%
2327
11th to 20thDay
11%426%7%5%6%6%6%9%38%
2303
21st to endDay
11%6%35%5%35%5%6%8%44%
2476
September1st to 10thDay
12%6%25%6%46%5%6%8%40%
2075
11th to 20thDay
10%5%25%435%6%6%10%44%
1980
21st to endDay
13%6%35%5%45%6%5%8%40%
1980
October1st to 10thDay
13%6%26%6%35%5%5%7%41%
1976
11th to 20thDay
18%9%36%6%45%5%46%33%
1799
21st to endDay
20%10%37%6%4445%7%29%
1782
November1st to 10thDay
12%8%47%6%3445%7%40%
1672
11th to 20thDay
15%14%5%8%6%44446%29%
1710
21st to endDay
20%12%6%7%6%25%446%27%
1710
December1st to 10thDay
14%16%10%10%5%445%5%424%
1710
11th to 20thDay
14%16%6%11%6%35%6%6%6%20%
1925
21st to endDay
21%21%7%10%9%4443412%
2783
January1st to 10thNight
17%15%9%10%7%34445%22%
4428
11th to 20thNight
15%16%7%14%8%45%6%6%6%13%
4440
21st to endNight
25%16%9%10%7%3444414%
4715
February1st to 10thNight
16%14%6%10%8%45%5%4423%
2457
11th to 20thNight
14%12%6%9%7%5%5%45%5%28%
2213
21st to endNight
19%11%5%10%5%35%446%28%
1776
March1st to 10thNight
16%9%47%7%3445%6%35%
2160
11th to 20thNight
14%10%35%435%5%6%6%38%
1981
21st to endNight
21%9%46%5%345%46%32%
2178
April1st to 10thNight
15%9%45%5%35%46%6%36%
1822
11th to 20thNight
19%8%35%4345%5%6%37%
1678
21st to endNight
17%8%36%6%2445%8%37%
1620
May1st to 10thNight
17%9%36%6%35%5%5%8%32%
1620
11th to 20thNight
20%7%25%43346%7%38%
1592
21st to endNight
11%6%245%345%6%9%44%
1683
June1st to 10thNight
10%3344445%6%9%48%
1440
11th to 20thNight
11%6%35%6%345%6%9%44%
1440
21st to endNight
9%425%4245%8%10%46%
1440
July1st to 10thNight
7%425%5%3445%8%53%
1440
11th to 20thNight
8%4245%25%46%8%52%
1440
21st to endNight
5%424435%5%7%10%50%
1664
August1st to 10thNight
8%41443446%9%50%
1611
11th to 20thNight
8%5%244346%6%8%49%
1598
21st to endNight
10%5%24435%5%5%6%51%
1876
September1st to 10thNight
10%6%25%5%3445%7%48%
1867
11th to 20thNight
10%5%24434447%53%
1980
21st to endNight
13%6%26%435%46%6%45%
1980
October1st to 10thNight
13%7%35%5%345%5%6%45%
1984
11th to 20thNight
18%11%46%6%34446%36%
2160
21st to endNight
21%10%36%6%35%446%32%
2574
November1st to 10thNight
13%10%36%6%25%345%42%
2406
11th to 20thNight
16%11%47%6%35%5%5%7%31%
2470
21st to endNight
17%14%5%7%6%3445%6%28%
2470
December1st to 10thNight
17%14%7%11%6%45%46%5%20%
2470
11th to 20thNight
15%14%7%11%7%45%45%5%22%
3269
21st to endNight
27%20%6%9%6%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
66%6%12%14%3
2528
11th to 20thDay
70%9%10%8%3
2530
21st to endDay
77%48%7%3
2943
February1st to 10thDay
63%7%10%13%6%1
1719
11th to 20thDay
61%6%9%15%8%1
1848
21st to endDay
62%6%11%14%6%1
1480
March1st to 10thDay
55%8%11%18%7%1
1800
11th to 20thDay
50%5%12%18%12%2
1979
21st to endDay
57%6%10%18%8%1
2178
April1st to 10thDay
55%6%10%19%10%
2153
11th to 20thDay
48%7%11%19%13%2
2230
21st to endDay
49%6%14%16%14%2
2340
May1st to 10thDay
49%8%12%19%10%1
2340
11th to 20thDay
49%6%10%19%14%2
2305
21st to endDay
40%8%15%24%12%2
2589
June1st to 10thDay
38%7%13%26%14%2
2520
11th to 20thDay
37%8%14%22%17%2
2520
21st to endDay
39%10%13%21%15%2
2520
July1st to 10thDay
33%8%13%24%18%4
2451
11th to 20thDay
35%8%12%25%18%2
2445
21st to endDay
34%9%14%23%17%2
2506
August1st to 10thDay
34%10%16%26%13%1
2314
11th to 20thDay
40%10%14%23%13%1
2303
21st to endDay
36%7%12%25%17%3
2476
September1st to 10thDay
40%9%15%20%14%2
2075
11th to 20thDay
34%8%12%30%16%1
1980
21st to endDay
40%7%14%21%17%
1980
October1st to 10thDay
41%7%11%25%14%2
1976
11th to 20thDay
52%6%11%21%11%1
1799
21st to endDay
55%6%13%17%8%1
1782
November1st to 10thDay
43%7%11%24%15%1
1672
11th to 20thDay
56%6%11%18%8%2
1710
21st to endDay
59%5%14%15%6%1
1710
December1st to 10thDay
64%7%11%13%4
1710
11th to 20thDay
61%8%13%14%3
1922
21st to endDay
76%6%9%6%3
2783
January1st to 10thNight
63%7%10%14%5%1
4428
11th to 20thNight
70%6%12%8%4
4440
21st to endNight
73%5%9%9%3
4715
February1st to 10thNight
63%7%10%13%6%2
2457
11th to 20thNight
57%6%10%18%8%1
2214
21st to endNight
58%313%16%8%2
1776
March1st to 10thNight
51%5%12%22%10%1
2160
11th to 20thNight
44%8%12%19%15%2
1981
21st to endNight
52%5%10%21%10%2
2178
April1st to 10thNight
46%7%11%21%14%1
1822
11th to 20thNight
46%6%12%17%17%2
1678
21st to endNight
47%5%12%19%14%3
1620
May1st to 10thNight
51%6%10%20%10%2
1620
11th to 20thNight
44%8%10%18%19%2
1593
21st to endNight
36%7%15%24%14%3
1684
June1st to 10thNight
33%6%13%28%17%2
1440
11th to 20thNight
35%8%13%25%16%2
1440
21st to endNight
31%9%15%26%18%2
1440
July1st to 10thNight
29%7%13%26%21%4
1400
11th to 20thNight
29%7%13%28%20%3
1392
21st to endNight
25%10%17%24%21%3
1572
August1st to 10thNight
29%8%15%31%15%2
1600
11th to 20thNight
30%9%15%28%15%3
1598
21st to endNight
32%6%12%27%21%3
1876
September1st to 10thNight
35%7%11%26%17%3
1867
11th to 20thNight
31%7%9%31%21%2
1980
21st to endNight
38%6%13%26%16%1
1980
October1st to 10thNight
40%5%11%23%19%1
1984
11th to 20thNight
49%6%11%20%14%1
2160
21st to endNight
52%6%11%21%9%1
2574
November1st to 10thNight
44%6%11%23%15%1
2406
11th to 20thNight
52%6%15%18%8%1
2470
21st to endNight
56%6%13%18%7%
2470
December1st to 10thNight
64%8%10%12%6%
2470
11th to 20thNight
61%7%13%13%5%
3271
21st to endNight
74%6%11%7%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
21%19%37%17%6%1
270
11th to 20thDay
22%18%42%15%21
270
21st to endDay
29%16%33%18%4
297
February1st to 10thDay
24%19%36%16%31
270
11th to 20thDay
26%18%39%15%2
267
21st to endDay
27%27%34%11%1
198
March1st to 10thDay
22%24%39%13%3
240
11th to 20thDay
22%12%37%22%6%1
419
21st to endDay
26%17%32%18%6%1
462
April1st to 10thDay
21%13%36%20%8%1
420
11th to 20thDay
24%18%31%16%7%4
412
21st to endDay
22%13%33%20%9%3
420
May1st to 10thDay
25%12%30%20%11%3
423
11th to 20thDay
21%9%30%21%12%7%
447
21st to endDay
14%8%21%28%20%8%
543
June1st to 10thDay
13%6%30%32%16%5%
630
11th to 20thDay
13%6%29%28%18%6%
630
21st to endDay
11%8%30%30%16%5%
630
July1st to 10thDay
7%420%30%25%13%
621
11th to 20thDay
12%5%23%28%21%11%
618
21st to endDay
9%326%28%24%10%
594
August1st to 10thDay
9%317%30%22%18%
446
11th to 20thDay
13%319%26%28%11%
439
21st to endDay
11%422%28%23%12%
495
September1st to 10thDay
15%5%22%23%23%12%
450
11th to 20thDay
10%421%23%30%13%
450
21st to endDay
16%11%21%26%19%8%
450
October1st to 10thDay
15%8%30%24%16%7%
450
11th to 20thDay
20%17%29%26%7%1
449
21st to endDay
30%15%36%14%41
297
November1st to 10thDay
13%17%34%26%8%2
270
11th to 20thDay
19%25%31%19%6%1
270
21st to endDay
27%14%41%15%3
270
December1st to 10thDay
23%27%31%11%7%
270
11th to 20thDay
22%23%39%13%3
270
21st to endDay
25%26%32%16%1
297
January1st to 10thNight
22%15%37%20%5%1
950
11th to 20thNight
23%15%36%21%5%1
950
21st to endNight
20%11%38%26%5%
941
February1st to 10thNight
24%14%38%21%4
760
11th to 20thNight
21%15%37%24%3
742
21st to endNight
26%13%41%17%3
592
March1st to 10thNight
21%13%35%25%7%
720
11th to 20thNight
18%14%38%23%6%1
720
21st to endNight
25%11%32%24%8%
792
April1st to 10thNight
18%14%37%26%5%1
562
11th to 20thNight
21%10%34%25%9%1
533
21st to endNight
20%7%34%29%9%1
540
May1st to 10thNight
21%8%29%34%7%1
540
11th to 20thNight
24%429%29%14%1
531
21st to endNight
13%424%39%19%2
584
June1st to 10thNight
12%224%45%16%
540
11th to 20thNight
12%5%23%42%18%1
540
21st to endNight
10%321%43%20%3
540
July1st to 10thNight
8%215%42%28%4
525
11th to 20thNight
8%317%44%25%3
522
21st to endNight
6%120%44%28%1
591
August1st to 10thNight
9%213%44%29%3
537
11th to 20thNight
8%215%40%30%5%
534
21st to endNight
12%215%37%29%4
594
September1st to 10thNight
12%317%38%25%5%
607
11th to 20thNight
12%417%35%29%4
720
21st to endNight
15%6%22%30%21%5%
720
October1st to 10thNight
16%6%27%31%19%2
720
11th to 20thNight
20%15%29%26%8%1
720
21st to endNight
27%12%33%22%6%
792
November1st to 10thNight
19%11%31%28%11%1
740
11th to 20thNight
22%15%34%23%6%
760
21st to endNight
24%12%34%25%4
760
December1st to 10thNight
23%14%38%20%5%
760
11th to 20thNight
23%14%38%21%4
940
21st to endNight
31%13%35%19%2
1045
Page generated at 2024-02-17 06:28:36. Version ac07

Copyright 2024 Attilla Danko


Jackson Clear Sky Chart |Charts Home