La Crosse
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the La Crosse clear sky chart from 2005-11-05 to 2017-08-12.

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
36%
15967
16%
46502
9%
15920
42%
15920
23%
31470

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
25%
900
12%
2506
5%
895
30%
895
17%
1855
January16th to endNight
21%
960
11%
2589
3%
960
27%
960
16%
1987
February1st to 15thNight
26%
879
13%
2288
4%
875
32%
875
20%
1670
February16th to endNight
27%
681
17%
1943
7%
681
36%
681
21%
1367
March1st to 15thNight
30%
648
15%
2088
9%
648
35%
648
19%
1394
March16th to endNight
34%
576
16%
2046
14%
576
42%
576
18%
1387
April1st to 15thNight
26%
539
16%
1797
10%
539
36%
539
19%
1214
April16th to endNight
32%
540
16%
1773
11%
540
42%
540
19%
1234
May1st to 15thNight
32%
540
17%
1446
8%
540
40%
540
24%
1019
May16th to endNight
44%
563
16%
1497
7%
561
51%
561
31%
968
June1st to 15thNight
48%
540
14%
1440
7%
540
51%
540
30%
946
June16th to endNight
52%
540
17%
1440
8%
540
57%
540
37%
886
July1st to 15thNight
62%
510
17%
1360
9%
510
65%
510
46%
769
July16th to endNight
69%
564
21%
1417
14%
531
71%
531
43%
820
August1st to 15thNight
68%
527
22%
1537
20%
524
71%
524
36%
896
August16th to endNight
57%
525
21%
1710
21%
525
62%
525
32%
979
September1st to 15thNight
56%
495
25%
1650
23%
495
64%
495
32%
933
September16th to endNight
49%
583
23%
1788
16%
583
57%
583
32%
1043
October1st to 15thNight
37%
660
24%
1980
15%
660
44%
660
30%
1200
October16th to endNight
34%
704
17%
2170
10%
704
42%
704
21%
1450
November1st to 15thNight
29%
733
21%
2309
13%
733
39%
733
24%
1462
November16th to endNight
25%
900
14%
2520
6%
900
32%
900
17%
1846
December1st to 15thNight
20%
900
9%
2520
3%
900
26%
900
13%
1967
December16th to endNight
17%
960
10%
2688
4%
960
23%
960
11%
2178

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%8%36%5%3445%7%36%
47479
Night
13%8%36%5%34446%39%
46671
Cloud CoverDay
27%6%25%423346%32%
47490
Night
26%7%25%423335%35%
46675
Cloud CoverDay
14%8%36%5%3445%7%36%
47488
Night
13%8%36%5%34446%39%
46675
TransparencyDay
46%6%13%22%10%
47165
Night
45%5%12%23%12%1
46503
SeeingDay
17%8%28%26%14%4
5931
Night
17%8%30%30%11%1
15968

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
9%11%7%8%8%47%5%5%5%25%
1432
16th to endDay
13%14%6%10%7%34446%22%
1635
February1st to 15thDay
10%14%5%8%4345%5%6%32%
1575
16th to endDay
13%10%36%8%3445%6%33%
1530
March1st to 15thDay
14%10%5%5%5%34445%36%
1870
16th to endDay
18%11%35%5%2435%6%32%
2177
April1st to 15thDay
18%10%36%5%34445%33%
2151
16th to endDay
23%9%345%2335%6%32%
2184
May1st to 15thDay
19%8%36%6%25%45%8%29%
2502
16th to endDay
14%5%36%5%35%5%5%7%35%
2617
June1st to 15thDay
13%5%25%5%35%5%6%8%39%
2520
16th to endDay
11%5%246%36%5%5%10%38%
2520
July1st to 15thDay
7%314436%5%6%8%48%
2520
16th to endDay
10%325%435%6%6%9%42%
2655
August1st to 15thDay
8%4246%35%5%7%9%42%
2325
16th to endDay
13%42442445%8%43%
2140
September1st to 15thDay
14%4234245%5%6%45%
1980
16th to endDay
14%6%25%434447%42%
1829
October1st to 15thDay
16%7%145%13335%46%
1650
16th to endDay
18%9%26%423346%38%
1702
November1st to 15thDay
13%8%45%6%2335%5%41%
1549
16th to endDay
14%9%46%435%346%37%
1440
December1st to 15thDay
17%12%6%8%6%25%5%45%26%
1440
16th to endDay
19%15%7%9%7%4433420%
1536
January1st to 15thNight
13%9%5%8%6%5%5%445%30%
2506
16th to endNight
12%11%5%10%6%35%5%5%5%25%
2589
February1st to 15thNight
9%13%5%7%6%35%345%35%
2285
16th to endNight
12%9%47%5%34345%37%
1943
March1st to 15thNight
13%10%46%42434440%
2076
16th to endNight
17%10%26%5%2345%6%34%
2046
April1st to 15thNight
20%8%35%424346%36%
1797
16th to endNight
21%9%24423446%34%
1773
May1st to 15thNight
21%6%25%32435%7%37%
1446
16th to endNight
11%5%24425%46%8%44%
1496
June1st to 15thNight
12%42443446%8%42%
1440
16th to endNight
7%5%24424349%50%
1440
July1st to 15thNight
5%313323448%58%
1440
16th to endNight
5%3133245%6%9%53%
1513
August1st to 15thNight
6%224425%5%5%9%50%
1546
16th to endNight
11%5%13323346%53%
1710
September1st to 15thNight
12%5%14223447%52%
1650
16th to endNight
10%42442345%6%52%
1788
October1st to 15thNight
15%5%24323235%50%
1980
16th to endNight
16%7%35%433445%40%
2170
November1st to 15thNight
12%8%45%42334444%
2309
16th to endNight
15%12%47%5%34445%33%
2520
December1st to 15thNight
16%11%5%9%7%45%445%26%
2520
16th to endNight
19%15%6%9%6%24335%22%
2688

Percentage Cloud Cover SW (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
23%8%47%7%45%5%5%423%
1432
16th to endDay
27%12%5%9%6%33345%18%
1635
February1st to 15thDay
24%11%46%423345%28%
1575
16th to endDay
26%9%26%6%33335%29%
1530
March1st to 15thDay
28%7%3341423433%
1881
16th to endDay
31%9%14423345%28%
2177
April1st to 15thDay
32%8%25%43333428%
2151
16th to endDay
36%9%24322245%25%
2184
May1st to 15thDay
32%7%25%424346%25%
2502
16th to endDay
30%425%433446%29%
2617
June1st to 15thDay
29%424423447%31%
2520
16th to endDay
26%4235%345%5%7%32%
2520
July1st to 15thDay
23%31342445%6%39%
2520
16th to endDay
25%314423447%36%
2655
August1st to 15thDay
17%3145%2446%9%40%
2325
16th to endDay
20%41431345%7%42%
2140
September1st to 15thDay
21%413433446%42%
1980
16th to endDay
21%5%1442345%5%40%
1829
October1st to 15thDay
25%42341233442%
1650
16th to endDay
26%7%25%312335%36%
1702
November1st to 15thDay
24%7%345%2334437%
1549
16th to endDay
28%7%35%42323434%
1440
December1st to 15thDay
31%10%47%5%2343423%
1440
16th to endDay
33%12%48%6%3332317%
1536
January1st to 15thNight
24%7%47%6%4443427%
2506
16th to endNight
27%10%38%5%3444422%
2589
February1st to 15thNight
23%11%36%42333431%
2278
16th to endNight
24%8%26%5%23335%32%
1943
March1st to 15thNight
26%8%35%32333335%
2088
16th to endNight
30%9%24422345%30%
2046
April1st to 15thNight
33%6%1441334432%
1797
16th to endNight
35%7%14322345%28%
1773
May1st to 15thNight
35%5%14323235%32%
1445
16th to endNight
27%414414346%38%
1496
June1st to 15thNight
27%42342445%6%34%
1440
16th to endNight
24%413313337%42%
1440
July1st to 15thNight
21%313213337%47%
1440
16th to endNight
21%3332335%6%46%
1513
August1st to 15thNight
14%213425%45%8%47%
1546
16th to endNight
19%413313345%50%
1710
September1st to 15thNight
19%413322336%49%
1650
16th to endNight
18%314323445%49%
1788
October1st to 15thNight
24%413322225%47%
1980
16th to endNight
24%5%2443334437%
2170
November1st to 15thNight
25%7%2432223341%
2309
16th to endNight
28%10%26%42333430%
2520
December1st to 15thNight
31%9%38%6%2433422%
2520
16th to endNight
32%13%49%5%1332319%
2688

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 15thDay
10%11%7%8%8%47%5%6%5%25%
1432
16th to endDay
13%15%6%10%7%3445%6%21%
1635
February1st to 15thDay
10%14%5%8%4345%5%6%32%
1575
16th to endDay
13%10%37%8%3445%6%33%
1530
March1st to 15thDay
14%10%5%5%5%34445%36%
1881
16th to endDay
18%11%35%5%3435%6%32%
2175
April1st to 15thDay
18%10%46%5%34345%33%
2151
16th to endDay
23%10%345%2335%6%32%
2184
May1st to 15thDay
19%8%26%6%25%45%7%29%
2502
16th to endDay
14%5%26%5%35%5%6%7%35%
2617
June1st to 15thDay
13%5%25%5%35%5%5%8%39%
2520
16th to endDay
11%5%246%36%5%6%10%38%
2520
July1st to 15thDay
7%314436%6%6%8%47%
2520
16th to endDay
10%424435%6%6%9%43%
2655
August1st to 15thDay
7%4146%346%6%9%42%
2325
16th to endDay
13%425%5%2445%8%43%
2140
September1st to 15thDay
14%42443445%7%45%
1980
16th to endDay
14%7%25%433447%42%
1829
October1st to 15thDay
16%7%14414335%45%
1650
16th to endDay
18%9%36%423346%38%
1702
November1st to 15thDay
13%8%36%5%23445%41%
1549
16th to endDay
14%9%46%5%24445%37%
1440
December1st to 15thDay
17%11%6%9%6%35%5%45%26%
1440
16th to endDay
20%15%6%9%8%3433420%
1536
January1st to 15thNight
13%10%5%8%6%5%5%446%30%
2506
16th to endNight
12%12%5%10%6%35%5%5%5%25%
2589
February1st to 15thNight
9%13%5%7%6%35%445%35%
2278
16th to endNight
12%9%47%6%34345%37%
1943
March1st to 15thNight
13%10%46%42444440%
2088
16th to endNight
17%10%36%42345%6%34%
2046
April1st to 15thNight
20%8%25%42435%5%36%
1797
16th to endNight
21%9%24424446%34%
1773
May1st to 15thNight
20%6%25%32435%7%37%
1445
16th to endNight
11%5%25%425%46%7%44%
1496
June1st to 15thNight
12%4344345%6%8%42%
1440
16th to endNight
7%5%14424349%50%
1440
July1st to 15thNight
5%323324338%58%
1440
16th to endNight
5%3133145%6%9%54%
1513
August1st to 15thNight
6%214435%5%5%9%50%
1546
16th to endNight
11%5%13323346%53%
1710
September1st to 15thNight
11%5%14222347%52%
1650
16th to endNight
10%42432345%6%52%
1788
October1st to 15thNight
16%5%24323235%51%
1980
16th to endNight
16%7%25%5%33445%40%
2170
November1st to 15thNight
12%8%45%42335%444%
2309
16th to endNight
14%12%46%5%34445%33%
2520
December1st to 15thNight
16%11%5%9%7%44445%26%
2520
16th to endNight
19%15%7%10%6%24325%22%
2688

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
58%5%13%14%7%
1433
16th to endDay
61%415%13%5%
1635
February1st to 15thDay
52%415%17%8%
1576
16th to endDay
51%5%11%22%7%
1530
March1st to 15thDay
50%414%20%8%1
1881
16th to endDay
52%5%13%22%5%1
2177
April1st to 15thDay
53%411%20%10%
2151
16th to endDay
52%5%11%18%9%1
2184
May1st to 15thDay
52%5%12%20%7%
2502
16th to endDay
45%7%11%20%14%1
2621
June1st to 15thDay
41%7%13%24%12%1
2520
16th to endDay
40%8%13%23%12%1
2520
July1st to 15thDay
32%8%14%27%15%1
2371
16th to endDay
35%8%15%23%15%1
2488
August1st to 15thDay
35%7%14%28%13%1
2310
16th to endDay
38%5%14%26%13%1
2140
September1st to 15thDay
37%6%13%27%15%
1980
16th to endDay
40%5%14%27%10%
1829
October1st to 15thDay
40%49%29%14%
1650
16th to endDay
47%414%23%8%
1702
November1st to 15thDay
43%414%22%13%1
1549
16th to endDay
48%5%19%19%6%
1440
December1st to 15thDay
59%5%13%16%4
1440
16th to endDay
68%5%9%12%3
1536
January1st to 15thNight
54%412%20%6%
2506
16th to endNight
58%414%15%6%
2589
February1st to 15thNight
51%412%21%9%
2288
16th to endNight
48%5%12%23%9%1
1943
March1st to 15thNight
47%5%12%22%10%1
2088
16th to endNight
50%413%23%7%
2046
April1st to 15thNight
48%49%20%14%2
1797
16th to endNight
49%5%10%17%13%3
1773
May1st to 15thNight
46%5%11%24%12%
1446
16th to endNight
36%7%12%24%17%1
1498
June1st to 15thNight
38%6%12%27%14%
1440
16th to endNight
31%6%12%27%18%3
1440
July1st to 15thNight
25%414%33%20%2
1360
16th to endNight
24%7%16%30%17%3
1417
August1st to 15thNight
29%6%12%28%19%2
1537
16th to endNight
32%5%12%30%14%4
1710
September1st to 15thNight
32%5%10%26%24%
1650
16th to endNight
32%6%12%32%16%
1788
October1st to 15thNight
37%310%28%18%2
1980
16th to endNight
45%5%11%23%13%
2170
November1st to 15thNight
42%312%22%16%1
2309
16th to endNight
53%413%21%5%
2520
December1st to 15thNight
60%5%11%17%4
2520
16th to endNight
65%412%11%5%
2688

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
26%14%31%20%6%1
90
16th to endDay
26%15%33%19%5%
96
February1st to 15thDay
15%21%42%17%3
90
16th to endDay
22%12%37%23%4
81
March1st to 15thDay
20%15%44%14%5%
90
16th to endDay
34%8%23%21%10%1
161
April1st to 15thDay
25%8%31%23%9%
270
16th to endDay
30%10%25%20%10%1
294
May1st to 15thDay
23%15%28%22%7%2
468
16th to endDay
18%12%29%23%11%4
517
June1st to 15thDay
15%5%30%29%15%3
495
16th to endDay
11%10%34%25%14%3
495
July1st to 15thDay
7%327%32%20%8%
475
16th to endDay
10%425%31%21%6%
515
August1st to 15thDay
8%224%33%22%8%
474
16th to endDay
15%5%17%28%24%7%
308
September1st to 15thDay
13%423%32%15%9%
255
16th to endDay
16%10%26%24%17%3
205
October1st to 15thDay
11%7%34%26%14%5%
90
16th to endDay
26%12%27%25%9%
96
November1st to 15thDay
7%7%36%35%8%3
90
16th to endDay
37%11%31%13%6%
90
December1st to 15thDay
25%13%41%16%3
90
16th to endDay
36%15%36%11%
96
January1st to 15thNight
16%13%36%25%7%
900
16th to endNight
19%10%37%27%4
960
February1st to 15thNight
16%12%35%28%6%
880
16th to endNight
17%12%36%25%8%
681
March1st to 15thNight
20%10%31%29%7%1
648
16th to endNight
21%9%27%28%12%1
576
April1st to 15thNight
24%8%35%23%6%
539
16th to endNight
25%6%30%27%8%
540
May1st to 15thNight
22%7%33%29%5%1
540
16th to endNight
13%6%29%36%12%1
563
June1st to 15thNight
14%5%25%42%12%
540
16th to endNight
10%329%41%14%1
540
July1st to 15thNight
6%223%37%27%2
510
16th to endNight
6%215%48%25%2
564
August1st to 15thNight
7%16%43%28%2
527
16th to endNight
13%321%34%23%3
525
September1st to 15thNight
15%220%35%18%6%
495
16th to endNight
12%7%25%33%18%2
583
October1st to 15thNight
19%8%31%24%15%1
660
16th to endNight
21%9%27%31%9%
704
November1st to 15thNight
17%11%36%25%8%1
733
16th to endNight
20%15%32%24%7%
900
December1st to 15thNight
22%12%36%22%6%
900
16th to endNight
26%10%31%24%6%
960
Page generated at 2017-08-13 13:16:18. Version ac04

Copyright 2017 A. Danko


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