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 2005-11-06 to 2024-01-16.

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%
24968
14%
74340
8%
24906
41%
24906
20%
52172

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
29%
950
14%
2648
6%
946
36%
946
19%
1915
January11th to 20thNight
20%
926
9%
2591
3%
926
25%
926
13%
2037
January21st to endNight
22%
990
11%
2704
3%
990
28%
990
15%
2083
February1st to 10thNight
26%
900
14%
2340
2%
900
34%
900
21%
1700
February11th to 20thNight
28%
879
19%
2273
5%
874
37%
874
24%
1588
February21st to endNight
29%
655
18%
1839
6%
655
39%
655
22%
1279
March1st to 10thNight
33%
692
15%
2132
9%
692
39%
692
20%
1485
March11th to 20thNight
31%
540
19%
1980
12%
540
43%
540
19%
1278
March21st to endNight
32%
594
17%
2093
13%
594
41%
594
17%
1439
April1st to 10thNight
28%
540
13%
1800
8%
540
37%
540
18%
1250
April11th to 20thNight
35%
533
15%
1775
13%
533
41%
533
18%
1229
April21st to endNight
37%
540
16%
1594
11%
540
43%
540
20%
1145
May1st to 10thNight
36%
540
14%
1440
8%
540
39%
540
24%
1022
May11th to 20thNight
45%
531
16%
1416
9%
531
48%
531
26%
977
May21st to endNight
49%
584
11%
1552
6%
582
51%
582
23%
1104
June1st to 10thNight
51%
540
9%
1440
5%
540
53%
540
27%
976
June11th to 20thNight
50%
540
12%
1362
7%
540
53%
540
28%
946
June21st to endNight
54%
540
13%
1260
7%
540
55%
540
30%
885
July1st to 10thNight
66%
525
14%
1288
8%
525
68%
525
44%
781
July11th to 20thNight
56%
522
16%
1392
8%
522
58%
522
37%
865
July21st to endNight
64%
591
18%
1487
10%
558
67%
558
43%
876
August1st to 10thNight
59%
537
21%
1458
13%
534
63%
534
37%
871
August11th to 20thNight
57%
534
20%
1600
17%
534
62%
534
32%
963
August21st to endNight
55%
594
19%
1915
19%
594
60%
594
29%
1138
September1st to 10thNight
56%
540
19%
1800
19%
540
62%
540
31%
1054
September11th to 20thNight
55%
540
20%
1800
19%
540
60%
540
30%
1055
September21st to endNight
40%
661
15%
2040
8%
661
46%
661
23%
1346
October1st to 10thNight
37%
720
16%
2160
10%
720
42%
720
23%
1442
October11th to 20thNight
28%
720
17%
2160
7%
720
37%
720
19%
1504
October21st to endNight
28%
792
13%
2506
7%
792
35%
792
15%
1815
November1st to 10thNight
30%
839
16%
2505
8%
839
37%
839
18%
1773
November11th to 20thNight
26%
950
13%
2660
4%
950
33%
950
15%
1989
November21st to endNight
26%
950
13%
2660
5%
950
33%
950
18%
1924
December1st to 10thNight
24%
950
10%
2660
4%
950
30%
950
12%
2077
December11th to 20thNight
20%
949
10%
3200
2%
948
26%
948
9%
2494
December21st to endNight
15%
1040
6%
4810
2%
1026
23%
1026
7%
3867

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%46%6%35%5%5%7%37%
75122
Night
14%9%36%5%345%5%7%38%
74670
TransparencyDay
46%8%14%22%9%1
74827
Night
47%8%13%22%9%1
74500
SeeingDay
16%9%29%30%13%2
14941
Night
17%8%31%31%12%1
24977

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 10thDay
9%12%6%9%7%35%447%34%
1517
11th to 20thDay
11%13%6%11%8%4446%8%25%
1480
21st to endDay
9%11%7%10%9%5%7%5%6%7%24%
1647
February1st to 10thDay
9%10%6%9%7%35%5%5%7%34%
1620
11th to 20thDay
10%11%47%5%35%45%8%38%
1574
21st to endDay
8%12%5%7%7%35%6%5%7%35%
1417
March1st to 10thDay
12%8%47%7%36%5%5%7%36%
1838
11th to 20thDay
13%10%36%7%3445%7%38%
1980
21st to endDay
19%9%47%5%35%5%5%6%31%
2262
April1st to 10thDay
16%10%47%7%44446%32%
2160
11th to 20thDay
19%10%48%5%35%5%46%31%
2134
21st to endDay
21%9%46%6%3445%6%32%
2362
May1st to 10thDay
17%9%46%7%34336%36%
2520
11th to 20thDay
17%6%346%445%5%8%38%
2479
21st to endDay
17%6%37%6%345%6%8%36%
2725
June1st to 10thDay
12%5%24436%5%7%9%44%
2520
11th to 20thDay
15%5%35%6%345%6%8%41%
2592
21st to endDay
14%5%25%5%46%6%7%10%36%
2700
July1st to 10thDay
7%314435%5%7%10%50%
2628
11th to 20thDay
9%5%25%5%35%6%6%9%45%
2520
21st to endDay
6%4245%25%5%7%10%51%
2743
August1st to 10thDay
9%425%6%45%6%7%9%44%
2469
11th to 20thDay
12%426%5%345%5%8%45%
2301
21st to endDay
13%5%25%5%3445%8%46%
2440
September1st to 10thDay
10%5%26%5%45%5%5%8%46%
2160
11th to 20thDay
15%5%25%5%35%5%6%7%42%
2160
21st to endDay
17%7%36%5%3345%7%39%
1898
October1st to 10thDay
17%7%36%6%45%5%5%6%34%
1800
11th to 20thDay
17%11%46%6%3446%7%32%
1800
21st to endDay
20%10%47%6%45%45%5%30%
1850
November1st to 10thDay
14%10%37%7%26%5%5%7%33%
1569
11th to 20thDay
15%12%7%10%8%46%45%427%
1520
21st to endDay
13%12%5%7%7%35%5%5%7%30%
1520
December1st to 10thDay
12%12%5%8%8%5%6%5%5%8%27%
1520
11th to 20thDay
14%17%7%9%8%35%5%5%5%23%
1914
21st to endDay
26%20%5%7%5%2333322%
2783
January1st to 10thNight
10%9%5%7%6%47%5%6%7%35%
2648
11th to 20thNight
11%13%5%10%7%45%5%5%7%27%
2591
21st to endNight
11%13%6%9%6%45%5%5%7%29%
2704
February1st to 10thNight
7%12%5%8%7%35%6%5%6%37%
2340
11th to 20thNight
8%10%38%5%35%45%6%43%
2273
21st to endNight
11%11%48%6%3346%7%37%
1839
March1st to 10thNight
10%10%48%6%35%5%5%7%37%
2124
11th to 20thNight
13%9%36%5%25%5%46%41%
1979
21st to endNight
16%10%5%8%5%35%445%36%
2093
April1st to 10thNight
15%12%47%6%2445%6%34%
1800
11th to 20thNight
19%10%36%6%245%5%6%35%
1775
21st to endNight
20%10%37%5%345%45%34%
1594
May1st to 10thNight
17%7%36%5%3445%7%39%
1440
11th to 20thNight
15%7%25%5%345%5%6%42%
1416
21st to endNight
17%6%35%5%35%5%6%8%38%
1551
June1st to 10thNight
14%5%15%5%35%47%9%42%
1440
11th to 20thNight
13%8%25%435%5%6%8%41%
1362
21st to endNight
12%6%25%4345%6%10%43%
1260
July1st to 10thNight
6%4133335%6%9%57%
1326
11th to 20thNight
8%3245%3447%8%52%
1440
21st to endNight
7%4143245%6%9%55%
1575
August1st to 10thNight
9%415%435%5%47%54%
1467
11th to 20thNight
12%5%3342335%7%51%
1600
21st to endNight
14%6%24423448%50%
1915
September1st to 10thNight
10%5%245%345%5%7%52%
1800
11th to 20thNight
13%5%244235%5%7%51%
1800
21st to endNight
16%6%25%5%35%45%7%41%
2040
October1st to 10thNight
18%5%26%5%4445%6%42%
2160
11th to 20thNight
17%8%36%6%345%5%8%36%
2160
21st to endNight
20%8%36%6%345%5%7%33%
2506
November1st to 10thNight
14%9%36%5%45%5%5%8%36%
2505
11th to 20thNight
16%11%46%6%46%45%7%31%
2660
21st to endNight
14%9%36%5%45%6%6%7%36%
2660
December1st to 10thNight
11%12%5%9%7%46%6%6%7%28%
2660
11th to 20thNight
12%15%5%8%7%35%6%6%6%27%
3283
21st to endNight
26%20%5%6%42233425%
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
54%6%13%20%6%
1518
11th to 20thDay
61%8%11%16%4
1480
21st to endDay
59%8%11%13%8%
1647
February1st to 10thDay
48%7%15%19%10%1
1620
11th to 20thDay
45%6%15%22%11%1
1583
21st to endDay
47%9%12%19%12%2
1417
March1st to 10thDay
48%7%17%20%8%1
1840
11th to 20thDay
45%8%16%21%10%1
1980
21st to endDay
50%9%12%20%8%1
2262
April1st to 10thDay
52%6%11%17%12%2
2160
11th to 20thDay
53%6%12%17%10%2
2134
21st to endDay
50%7%12%20%10%1
2362
May1st to 10thDay
48%7%12%22%9%2
2520
11th to 20thDay
43%9%13%23%9%2
2483
21st to endDay
44%9%14%22%11%1
2725
June1st to 10thDay
35%11%18%24%12%1
2520
11th to 20thDay
41%8%15%22%14%1
2592
21st to endDay
41%9%17%25%8%1
2700
July1st to 10thDay
26%10%15%31%17%1
2558
11th to 20thDay
32%11%14%26%15%1
2445
21st to endDay
25%10%20%29%15%1
2591
August1st to 10thDay
33%10%17%29%9%2
2454
11th to 20thDay
36%8%17%27%11%
2301
21st to endDay
34%8%15%29%13%1
2440
September1st to 10thDay
34%9%18%30%9%
2160
11th to 20thDay
38%10%18%27%7%
2160
21st to endDay
44%7%15%26%7%
1898
October1st to 10thDay
47%9%15%23%5%
1800
11th to 20thDay
50%8%14%18%9%
1800
21st to endDay
55%8%12%18%6%1
1850
November1st to 10thDay
50%7%12%21%9%1
1569
11th to 20thDay
62%6%12%13%5%
1520
21st to endDay
55%9%13%16%5%1
1520
December1st to 10thDay
59%8%16%14%3
1520
11th to 20thDay
65%8%9%13%41
1915
21st to endDay
70%6%7%11%5%
2783
January1st to 10thNight
49%8%14%23%5%
2648
11th to 20thNight
58%9%13%16%31
2591
21st to endNight
57%7%11%17%7%
2704
February1st to 10thNight
49%6%13%19%11%1
2340
11th to 20thNight
44%7%13%23%12%1
2274
21st to endNight
47%6%12%24%10%2
1839
March1st to 10thNight
46%8%14%19%11%2
2135
11th to 20thNight
44%7%12%23%14%1
1980
21st to endNight
51%5%12%19%11%2
2093
April1st to 10thNight
51%6%9%17%16%1
1800
11th to 20thNight
51%6%11%19%12%1
1775
21st to endNight
51%7%7%23%12%1
1594
May1st to 10thNight
46%8%13%23%9%1
1440
11th to 20thNight
42%8%10%25%12%2
1417
21st to endNight
44%10%9%23%12%2
1552
June1st to 10thNight
39%9%15%24%11%2
1440
11th to 20thNight
40%10%11%22%16%2
1362
21st to endNight
38%9%13%25%13%1
1260
July1st to 10thNight
24%9%17%32%17%1
1288
11th to 20thNight
29%9%13%28%17%3
1392
21st to endNight
25%8%19%30%15%3
1487
August1st to 10thNight
29%8%15%34%10%4
1458
11th to 20thNight
34%6%17%28%13%2
1600
21st to endNight
34%7%13%27%17%1
1915
September1st to 10thNight
32%8%15%32%12%1
1800
11th to 20thNight
33%7%19%32%9%
1800
21st to endNight
41%8%15%27%8%
2040
October1st to 10thNight
44%7%13%27%9%1
2160
11th to 20thNight
47%7%13%23%8%1
2160
21st to endNight
52%8%13%20%7%
2506
November1st to 10thNight
48%8%13%23%7%1
2505
11th to 20thNight
54%8%16%15%8%
2660
21st to endNight
48%9%18%18%6%1
2660
December1st to 10thNight
59%8%13%17%4
2660
11th to 20thNight
59%8%12%16%4
3281
21st to endNight
66%7%8%15%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
15%10%35%29%10%1
270
11th to 20thDay
17%8%35%30%10%
255
21st to endDay
13%11%32%33%10%2
264
February1st to 10thDay
13%12%45%25%5%
240
11th to 20thDay
13%17%43%18%8%1
240
21st to endDay
16%15%39%28%2
198
March1st to 10thDay
15%9%33%34%8%1
240
11th to 20thDay
16%8%37%29%9%1
240
21st to endDay
23%10%30%26%9%2
348
April1st to 10thDay
21%13%31%27%7%1
420
11th to 20thDay
25%8%25%30%11%1
412
21st to endDay
24%9%28%26%11%1
582
May1st to 10thDay
20%9%35%26%6%3
603
11th to 20thDay
18%8%29%28%13%3
625
21st to endDay
18%7%26%32%14%3
679
June1st to 10thDay
11%6%30%36%13%3
630
11th to 20thDay
14%10%28%35%12%1
630
21st to endDay
13%7%27%33%17%3
630
July1st to 10thDay
9%423%38%21%6%
621
11th to 20thDay
10%6%28%31%19%6%
618
21st to endDay
6%424%40%20%6%
684
August1st to 10thDay
10%5%22%38%20%4
626
11th to 20thDay
13%6%19%33%25%4
615
21st to endDay
17%6%20%31%21%4
559
September1st to 10thDay
11%6%26%36%19%2
450
11th to 20thDay
16%7%26%30%19%3
450
21st to endDay
23%10%28%21%14%3
328
October1st to 10thDay
19%10%29%28%13%2
270
11th to 20thDay
17%17%34%24%6%1
270
21st to endDay
25%14%37%21%3
297
November1st to 10thDay
19%12%35%24%10%
270
11th to 20thDay
20%13%38%22%6%
270
21st to endDay
19%15%33%27%7%
270
December1st to 10thDay
16%16%34%26%7%1
270
11th to 20thDay
20%15%38%20%6%
270
21st to endDay
28%11%32%24%4
297
January1st to 10thNight
14%10%37%30%7%1
950
11th to 20thNight
17%8%42%25%8%1
926
21st to endNight
17%9%40%27%7%1
990
February1st to 10thNight
12%10%41%30%7%1
900
11th to 20thNight
13%10%41%26%10%1
879
21st to endNight
17%9%38%28%8%
655
March1st to 10thNight
15%8%34%34%8%1
695
11th to 20thNight
18%7%37%29%9%1
540
21st to endNight
21%6%29%27%13%3
594
April1st to 10thNight
20%8%36%28%8%
540
11th to 20thNight
24%8%25%31%11%1
533
21st to endNight
24%6%25%30%12%2
540
May1st to 10thNight
19%6%33%31%10%1
540
11th to 20thNight
20%5%23%35%14%2
531
21st to endNight
18%5%19%38%19%1
584
June1st to 10thNight
15%324%40%17%1
540
11th to 20thNight
16%422%44%13%1
540
21st to endNight
16%419%40%20%2
540
July1st to 10thNight
7%220%40%30%2
525
11th to 20thNight
9%227%36%25%1
522
21st to endNight
8%221%43%24%2
591
August1st to 10thNight
9%322%40%25%1
537
11th to 20thNight
15%318%35%25%4
534
21st to endNight
17%418%35%23%3
594
September1st to 10thNight
11%5%22%38%21%3
540
11th to 20thNight
15%422%38%20%1
540
21st to endNight
21%6%27%27%16%2
661
October1st to 10thNight
20%7%28%30%14%1
720
11th to 20thNight
19%10%35%27%8%1
720
21st to endNight
24%11%30%27%7%
792
November1st to 10thNight
18%12%34%28%8%
839
11th to 20thNight
19%14%33%24%9%1
950
21st to endNight
18%15%35%26%6%
950
December1st to 10thNight
18%13%35%27%6%
950
11th to 20thNight
21%11%36%23%8%1
950
21st to endNight
29%10%34%21%5%1
1045
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