This page made possible by the sponsorship of: Arrowhead Astronomical Society (Duluth,MN).

Korkki Road
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Korkki Road clear sky chart from 2005-11-05 to 2017-03-26.

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
26%
15678
14%
45127
6%
15630
34%
15630
18%
31457

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
20%
900
10%
2506
3%
895
25%
895
15%
1832
January16th to endNight
11%
960
12%
2643
1%
960
21%
960
12%
2012
February1st to 15thNight
17%
880
13%
2285
1%
875
25%
875
16%
1640
February16th to endNight
26%
732
15%
1994
5%
732
34%
732
18%
1412
March1st to 15thNight
28%
642
14%
2082
8%
642
35%
642
16%
1436
March16th to endNight
25%
561
17%
2005
10%
561
35%
561
14%
1358
April1st to 15thNight
22%
494
14%
1647
6%
494
34%
494
14%
1137
April16th to endNight
24%
495
15%
1523
6%
495
35%
495
14%
1076
May1st to 15thNight
24%
495
14%
1320
5%
495
30%
495
16%
981
May16th to endNight
37%
515
11%
1370
4%
513
41%
513
21%
952
June1st to 15thNight
33%
495
9%
1320
4%
495
37%
495
20%
918
June16th to endNight
31%
495
10%
1162
4%
495
35%
495
24%
825
July1st to 15thNight
44%
465
13%
1173
5%
465
47%
465
33%
744
July16th to endNight
42%
522
14%
1305
5%
489
49%
489
33%
804
August1st to 15thNight
51%
494
22%
1388
14%
491
56%
491
36%
797
August16th to endNight
44%
525
19%
1657
15%
525
52%
525
30%
952
September1st to 15thNight
43%
495
21%
1650
15%
495
55%
495
29%
937
September16th to endNight
41%
566
13%
1798
8%
566
47%
566
24%
1129
October1st to 15thNight
32%
660
19%
1980
9%
660
41%
660
21%
1261
October16th to endNight
22%
704
12%
2192
5%
704
30%
704
14%
1582
November1st to 15thNight
23%
823
16%
2399
6%
823
32%
823
16%
1679
November16th to endNight
21%
900
14%
2520
5%
900
29%
900
14%
1865
December1st to 15thNight
13%
900
8%
2520
2%
900
18%
900
9%
1984
December16th to endNight
14%
960
9%
2688
1%
960
21%
960
9%
2144

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%7%36%5%35%45%7%35%
45850
Night
13%8%36%5%3445%7%37%
45296
Cloud CoverDay
14%7%36%5%35%5%5%7%35%
45861
Night
14%8%36%5%3445%7%36%
45300
Cloud CoverDay
14%7%36%5%35%45%7%35%
45859
Night
14%8%36%5%3445%7%36%
45300
TransparencyDay
47%7%14%21%8%
45535
Night
47%6%14%22%8%
45130
SeeingDay
17%19%29%22%8%2
5379
Night
16%24%26%22%9%1
15678

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
10%11%6%8%6%34248%33%
1432
16th to endDay
10%11%6%10%7%45%5%6%7%23%
1578
February1st to 15thDay
10%10%5%8%6%35%35%7%35%
1575
16th to endDay
10%14%5%7%6%25%5%5%7%30%
1479
March1st to 15thDay
13%8%46%6%245%5%6%36%
1876
16th to endDay
18%9%37%5%35%5%46%29%
2105
April1st to 15thDay
15%8%46%6%34335%37%
1971
16th to endDay
21%9%36%5%2445%7%29%
2104
May1st to 15thDay
21%7%36%8%34346%30%
2301
16th to endDay
17%5%25%5%25%5%5%7%36%
2393
June1st to 15thDay
17%5%245%35%5%6%7%36%
2310
16th to endDay
15%5%25%5%35%5%7%8%34%
2464
July1st to 15thDay
9%424435%5%8%9%43%
2376
16th to endDay
6%415%426%5%7%10%45%
2459
August1st to 15thDay
9%425%5%35%5%6%7%43%
2230
16th to endDay
11%425%5%2336%9%44%
2193
September1st to 15thDay
8%425%5%35%447%46%
1980
16th to endDay
17%5%25%5%34446%40%
1821
October1st to 15thDay
14%7%46%5%35%5%5%6%36%
1650
16th to endDay
21%10%36%5%24445%30%
1680
November1st to 15thDay
16%9%47%6%25%45%6%32%
1457
16th to endDay
16%11%5%7%6%35%45%6%27%
1440
December1st to 15thDay
14%13%5%7%7%35%447%25%
1440
16th to endDay
19%16%6%9%6%3434420%
1536
January1st to 15thNight
11%11%46%5%36%5%5%7%31%
2506
16th to endNight
11%12%49%5%35%45%8%28%
2643
February1st to 15thNight
8%11%38%5%25%5%46%38%
2285
16th to endNight
9%11%37%6%3435%7%35%
1994
March1st to 15thNight
12%9%36%5%25%446%37%
2070
16th to endNight
16%9%46%5%24335%37%
2005
April1st to 15thNight
16%11%36%5%2445%5%34%
1647
16th to endNight
20%8%25%5%345%5%6%32%
1523
May1st to 15thNight
20%8%35%5%2445%5%34%
1320
16th to endNight
15%424435%5%6%7%39%
1368
June1st to 15thNight
17%6%15%5%2445%8%38%
1320
16th to endNight
15%7%25%32446%10%38%
1162
July1st to 15thNight
8%31333446%7%51%
1251
16th to endNight
7%314325%47%9%49%
1401
August1st to 15thNight
9%413224348%55%
1397
16th to endNight
13%423212448%52%
1657
September1st to 15thNight
7%3145%2345%6%53%
1650
16th to endNight
13%5%2443445%6%44%
1798
October1st to 15thNight
14%5%25%33445%7%44%
1980
16th to endNight
21%6%25%5%24446%34%
2192
November1st to 15thNight
14%9%35%5%3445%7%36%
2399
16th to endNight
16%9%36%445%5%47%32%
2520
December1st to 15thNight
15%13%5%7%5%35%5%5%6%26%
2520
16th to endNight
15%16%6%8%5%3335%5%24%
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
10%11%7%8%7%35%36%9%26%
1432
16th to endDay
9%11%6%11%8%47%5%6%8%20%
1578
February1st to 15thDay
9%10%5%7%6%2446%8%33%
1575
16th to endDay
11%13%5%6%6%3446%7%30%
1479
March1st to 15thDay
13%8%46%6%2345%6%37%
1887
16th to endDay
18%9%26%5%345%46%32%
2105
April1st to 15thDay
13%8%5%7%443446%38%
1971
16th to endDay
20%8%36%5%3345%7%31%
2104
May1st to 15thDay
20%6%37%6%35%445%31%
2301
16th to endDay
16%5%25%435%5%5%7%37%
2393
June1st to 15thDay
16%5%245%35%5%7%7%37%
2310
16th to endDay
15%5%24436%5%6%8%36%
2464
July1st to 15thDay
9%314425%6%7%9%45%
2376
16th to endDay
6%313425%5%6%9%49%
2459
August1st to 15thDay
8%415%5%26%6%5%8%45%
2230
16th to endDay
10%5%25%42345%8%47%
2193
September1st to 15thDay
8%424445%46%7%47%
1980
16th to endDay
16%5%2444345%5%41%
1821
October1st to 15thDay
13%6%37%5%25%5%46%37%
1650
16th to endDay
22%9%35%6%24446%31%
1680
November1st to 15thDay
15%9%47%5%35%445%33%
1457
16th to endDay
16%12%5%7%6%45%45%8%24%
1440
December1st to 15thDay
14%13%6%9%7%446%5%8%19%
1440
16th to endDay
19%17%7%9%6%3444417%
1536
January1st to 15thNight
11%11%5%6%7%45%6%5%11%24%
2506
16th to endNight
11%12%6%10%6%35%5%5%8%24%
2643
February1st to 15thNight
8%11%48%6%25%5%47%35%
2278
16th to endNight
9%11%36%6%3437%6%35%
1994
March1st to 15thNight
13%8%36%5%345%45%39%
2082
16th to endNight
16%9%35%5%33445%37%
2005
April1st to 15thNight
17%10%45%5%24445%34%
1647
16th to endNight
20%7%25%425%5%5%6%33%
1523
May1st to 15thNight
21%7%35%5%2445%6%34%
1319
16th to endNight
15%5%235%36%5%5%7%39%
1368
June1st to 15thNight
17%5%145%25%45%8%37%
1320
16th to endNight
16%7%2431447%8%38%
1162
July1st to 15thNight
8%3243345%5%8%50%
1251
16th to endNight
7%413425%46%9%48%
1401
August1st to 15thNight
9%314323347%55%
1397
16th to endNight
13%413313348%52%
1657
September1st to 15thNight
8%415%33345%7%53%
1650
16th to endNight
14%5%2442346%6%44%
1798
October1st to 15thNight
14%5%25%325%446%43%
1980
16th to endNight
21%6%25%6%25%45%6%33%
2192
November1st to 15thNight
15%8%35%425%45%7%36%
2399
16th to endNight
17%9%46%6%25%5%5%6%32%
2520
December1st to 15thNight
15%13%5%8%7%46%5%5%7%20%
2520
16th to endNight
16%16%7%8%5%35%5%47%20%
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%6%3435%9%29%
1432
16th to endDay
9%12%6%11%8%36%6%6%7%21%
1578
February1st to 15thDay
10%11%48%6%2435%8%33%
1575
16th to endDay
11%12%6%6%6%3445%8%29%
1479
March1st to 15thDay
13%8%46%5%3345%7%36%
1887
16th to endDay
18%9%36%5%35%446%31%
2103
April1st to 15thDay
14%8%5%6%5%33446%37%
1971
16th to endDay
21%8%36%43345%6%31%
2104
May1st to 15thDay
20%7%36%6%36%446%30%
2301
16th to endDay
16%5%25%5%35%5%5%8%36%
2393
June1st to 15thDay
16%5%24435%5%6%7%36%
2310
16th to endDay
15%5%25%5%26%5%7%8%35%
2464
July1st to 15thDay
8%414435%6%7%9%44%
2376
16th to endDay
6%414435%5%6%10%47%
2459
August1st to 15thDay
8%4145%35%6%6%8%44%
2230
16th to endDay
11%425%5%2336%9%45%
2193
September1st to 15thDay
8%4245%45%45%7%47%
1980
16th to endDay
16%5%245%2445%7%40%
1821
October1st to 15thDay
13%7%27%5%36%5%5%6%36%
1650
16th to endDay
22%9%36%5%34446%30%
1680
November1st to 15thDay
15%9%47%5%26%35%6%32%
1457
16th to endDay
16%11%5%7%6%45%36%7%24%
1440
December1st to 15thDay
14%14%6%8%7%345%5%7%23%
1440
16th to endDay
18%17%7%10%7%3433419%
1536
January1st to 15thNight
11%11%47%6%45%5%6%8%28%
2506
16th to endNight
10%12%5%10%6%35%5%6%8%25%
2643
February1st to 15thNight
8%11%48%5%35%5%47%36%
2278
16th to endNight
10%10%47%6%3436%7%34%
1994
March1st to 15thNight
12%9%36%5%345%45%38%
2082
16th to endNight
16%9%45%5%34436%37%
2005
April1st to 15thNight
16%11%35%5%34445%34%
1647
16th to endNight
20%8%25%5%25%5%5%6%32%
1523
May1st to 15thNight
21%8%35%5%24446%34%
1319
16th to endNight
14%5%235%36%5%6%7%39%
1368
June1st to 15thNight
17%5%25%5%3445%8%38%
1320
16th to endNight
15%7%35%315%46%10%37%
1162
July1st to 15thNight
9%32342446%7%50%
1251
16th to endNight
7%3134245%6%9%49%
1401
August1st to 15thNight
9%313322448%55%
1397
16th to endNight
13%423313348%51%
1657
September1st to 15thNight
8%424434446%54%
1650
16th to endNight
13%6%2442346%6%44%
1798
October1st to 15thNight
14%5%25%425%45%6%43%
1980
16th to endNight
21%6%35%5%25%446%33%
2192
November1st to 15thNight
14%9%35%425%46%7%36%
2399
16th to endNight
17%9%36%5%25%5%5%7%31%
2520
December1st to 15thNight
15%13%5%8%6%35%5%47%23%
2520
16th to endNight
16%16%6%8%5%34446%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
54%412%20%6%
1433
16th to endDay
59%8%11%15%4
1578
February1st to 15thDay
48%6%17%18%8%1
1576
16th to endDay
52%8%12%19%6%
1479
March1st to 15thDay
47%6%16%18%9%
1887
16th to endDay
51%9%13%18%6%1
2105
April1st to 15thDay
48%5%11%19%13%1
1971
16th to endDay
52%6%12%17%8%1
2104
May1st to 15thDay
55%6%11%18%6%1
2301
16th to endDay
43%7%14%21%11%
2397
June1st to 15thDay
43%8%17%22%7%
2310
16th to endDay
43%7%17%21%9%
2464
July1st to 15thDay
31%8%15%26%16%1
2226
16th to endDay
30%10%18%27%11%1
2292
August1st to 15thDay
35%8%16%26%11%1
2215
16th to endDay
35%6%18%26%13%
2193
September1st to 15thDay
34%7%18%32%6%
1980
16th to endDay
42%7%17%26%5%
1821
October1st to 15thDay
46%7%16%22%7%
1650
16th to endDay
55%6%13%16%6%
1680
November1st to 15thDay
52%5%12%20%8%
1457
16th to endDay
60%7%12%12%6%
1440
December1st to 15thDay
61%8%12%14%2
1440
16th to endDay
69%5%9%11%3
1536
January1st to 15thNight
52%6%14%22%4
2506
16th to endNight
56%6%14%17%4
2643
February1st to 15thNight
48%5%15%19%8%1
2288
16th to endNight
47%5%12%24%7%
1994
March1st to 15thNight
45%8%13%19%11%1
2082
16th to endNight
49%5%12%21%9%1
2005
April1st to 15thNight
51%49%19%13%1
1647
16th to endNight
49%6%9%22%10%
1523
May1st to 15thNight
51%7%12%20%7%
1320
16th to endNight
42%8%9%25%13%1
1370
June1st to 15thNight
44%7%12%24%10%1
1320
16th to endNight
41%7%13%24%10%1
1162
July1st to 15thNight
31%7%12%28%17%2
1173
16th to endNight
28%9%18%28%13%2
1305
August1st to 15thNight
28%5%18%30%13%3
1388
16th to endNight
32%5%15%27%16%2
1657
September1st to 15thNight
31%6%15%36%10%
1650
16th to endNight
38%7%18%27%7%
1798
October1st to 15thNight
39%6%15%28%9%
1980
16th to endNight
51%7%12%20%7%
2192
November1st to 15thNight
47%6%13%22%8%
2399
16th to endNight
52%7%16%16%6%1
2520
December1st to 15thNight
60%6%13%17%1
2520
16th to endNight
62%6%14%11%4
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
22%18%37%17%3
90
16th to endDay
18%14%36%25%5%
96
February1st to 15thDay
20%24%41%13%1
90
16th to endDay
23%25%32%12%6%
81
March1st to 15thDay
18%15%36%23%41
90
16th to endDay
29%19%28%13%34
132
April1st to 15thDay
19%26%28%18%7%
210
16th to endDay
22%25%29%14%6%1
309
May1st to 15thDay
21%28%26%16%42
393
16th to endDay
18%20%26%22%7%4
437
June1st to 15thDay
19%24%30%18%6%1
420
16th to endDay
15%22%28%21%10%1
420
July1st to 15thDay
11%15%30%25%13%3
400
16th to endDay
8%20%32%26%8%3
445
August1st to 15thDay
11%13%25%33%13%3
418
16th to endDay
14%13%22%31%13%4
361
September1st to 15thDay
9%12%28%29%15%4
255
16th to endDay
23%12%28%17%15%2
180
October1st to 15thDay
12%11%34%27%12%2
90
16th to endDay
31%18%31%15%3
96
November1st to 15thDay
20%16%45%12%5%
90
16th to endDay
37%7%26%23%4
90
December1st to 15thDay
25%15%43%13%11
90
16th to endDay
26%16%39%16%1
96
January1st to 15thNight
14%29%29%21%5%
900
16th to endNight
15%27%37%15%3
960
February1st to 15thNight
12%30%31%18%6%
880
16th to endNight
11%24%30%24%8%1
732
March1st to 15thNight
13%26%26%24%8%
642
16th to endNight
16%26%23%20%9%3
561
April1st to 15thNight
19%26%26%21%5%
494
16th to endNight
24%24%22%20%6%2
495
May1st to 15thNight
20%26%25%20%6%1
495
16th to endNight
16%22%19%27%13%1
515
June1st to 15thNight
16%23%22%28%8%1
495
16th to endNight
17%22%22%25%12%
495
July1st to 15thNight
11%15%24%30%16%1
465
16th to endNight
8%20%23%32%14%
522
August1st to 15thNight
11%12%19%30%22%3
494
16th to endNight
14%13%23%28%17%2
525
September1st to 15thNight
9%13%28%26%17%4
495
16th to endNight
15%14%23%28%16%1
566
October1st to 15thNight
17%20%25%25%9%1
660
16th to endNight
23%19%28%22%6%
704
November1st to 15thNight
16%26%27%21%7%
823
16th to endNight
17%30%24%19%7%
900
December1st to 15thNight
19%31%28%15%4
900
16th to endNight
20%27%28%17%6%
960
Page generated at 2017-03-27 10:15:17. Version ac04

Copyright 2017 A. Danko


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