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 2019-07-11.

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
27%
18723
14%
53874
6%
18675
35%
18675
19%
37282

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%
1050
12%
2926
3%
1045
27%
1045
16%
2107
January16th to endNight
12%
1120
12%
3083
1%
1120
22%
1120
14%
2319
February1st to 15thNight
16%
1030
14%
2675
1%
1025
25%
1025
16%
1927
February16th to endNight
24%
853
15%
2323
4%
853
32%
853
18%
1647
March1st to 15thNight
28%
750
16%
2430
7%
750
37%
750
16%
1667
March16th to endNight
27%
672
18%
2398
12%
672
38%
672
16%
1581
April1st to 15thNight
24%
629
14%
2097
7%
629
36%
629
16%
1432
April16th to endNight
27%
624
16%
1917
7%
624
37%
624
16%
1346
May1st to 15thNight
29%
630
13%
1680
6%
630
34%
630
19%
1222
May16th to endNight
39%
659
11%
1754
5%
657
42%
657
22%
1226
June1st to 15thNight
37%
630
11%
1680
5%
630
41%
630
23%
1131
June16th to endNight
36%
630
11%
1479
4%
630
39%
630
26%
1046
July1st to 15thNight
49%
588
14%
1482
7%
588
52%
588
37%
908
July16th to endNight
45%
612
16%
1545
6%
579
51%
579
35%
940
August1st to 15thNight
53%
575
22%
1614
15%
572
58%
572
37%
926
August16th to endNight
45%
621
20%
1960
16%
621
53%
621
29%
1149
September1st to 15thNight
45%
585
20%
1950
15%
585
55%
585
29%
1106
September16th to endNight
39%
670
13%
2126
9%
670
45%
670
24%
1354
October1st to 15thNight
30%
780
18%
2340
8%
780
38%
780
20%
1525
October16th to endNight
22%
832
13%
2590
5%
832
31%
832
15%
1853
November1st to 15thNight
23%
963
15%
2809
6%
963
31%
963
16%
1985
November16th to endNight
20%
1050
13%
2940
5%
1050
28%
1050
15%
2147
December1st to 15thNight
15%
1050
10%
2940
3%
1050
21%
1050
11%
2290
December16th to endNight
14%
1120
11%
3136
2%
1120
22%
1120
10%
2448

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%6%35%45%7%35%
55331
Night
13%8%36%5%3445%7%37%
54043
Cloud CoverDay
13%7%36%5%35%5%5%7%36%
55342
Night
14%8%36%5%3445%7%36%
54047
Cloud CoverDay
13%7%36%5%3445%7%35%
55340
Night
13%8%36%5%3445%7%37%
54047
TransparencyDay
46%7%14%21%8%
55016
Night
46%6%14%22%9%
53877
SeeingDay
17%16%31%23%8%2
8646
Night
16%21%27%23%9%1
18723

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%34247%32%
1672
16th to endDay
9%10%6%10%8%46%5%6%7%23%
1841
February1st to 15thDay
9%10%5%8%6%35%347%35%
1845
16th to endDay
10%13%5%7%6%35%5%47%30%
1722
March1st to 15thDay
12%8%46%6%35%5%5%6%36%
2190
16th to endDay
16%9%37%5%35%5%46%32%
2530
April1st to 15thDay
15%9%47%6%35%445%34%
2511
16th to endDay
20%9%36%5%24446%31%
2645
May1st to 15thDay
19%7%36%7%34347%32%
2931
16th to endDay
17%5%26%5%345%5%7%35%
3065
June1st to 15thDay
14%5%25%5%35%46%7%40%
2940
16th to endDay
14%5%25%5%35%5%7%9%33%
3136
July1st to 15thDay
9%314425%5%7%9%44%
2958
16th to endDay
6%414425%5%6%9%47%
2879
August1st to 15thDay
10%425%5%35%5%6%8%44%
2587
16th to endDay
13%425%5%2335%8%43%
2594
September1st to 15thDay
8%425%5%35%5%47%46%
2340
16th to endDay
18%6%25%5%34446%38%
2151
October1st to 15thDay
17%7%35%6%35%5%5%5%34%
1950
16th to endDay
21%9%36%5%24445%32%
1986
November1st to 15thDay
15%10%47%6%25%45%6%31%
1706
16th to endDay
15%12%5%7%7%35%45%6%26%
1680
December1st to 15thDay
13%13%5%8%7%35%5%46%25%
1680
16th to endDay
18%16%6%10%7%3434421%
1792
January1st to 15thNight
11%10%46%5%36%5%5%7%33%
2926
16th to endNight
10%11%49%6%35%5%5%7%29%
3083
February1st to 15thNight
8%11%48%5%24446%38%
2675
16th to endNight
10%11%37%5%3445%7%35%
2323
March1st to 15thNight
12%9%36%5%245%46%37%
2418
16th to endNight
14%8%46%424445%39%
2398
April1st to 15thNight
16%11%36%5%2435%5%35%
2097
16th to endNight
20%8%25%4245%5%5%34%
1917
May1st to 15thNight
19%7%25%5%3435%6%36%
1680
16th to endNight
15%5%25%435%5%5%8%38%
1752
June1st to 15thNight
15%6%15%42445%8%41%
1680
16th to endNight
14%6%25%33446%9%39%
1479
July1st to 15thNight
8%31333345%8%54%
1560
16th to endNight
7%31432446%9%51%
1641
August1st to 15thNight
9%413214447%55%
1623
16th to endNight
14%5%23213347%51%
1960
September1st to 15thNight
8%4145%23446%53%
1950
16th to endNight
14%6%25%43445%7%42%
2126
October1st to 15thNight
17%5%2433445%7%41%
2340
16th to endNight
21%6%25%5%34446%34%
2590
November1st to 15thNight
15%9%345%3445%7%35%
2809
16th to endNight
15%9%36%4345%5%7%33%
2940
December1st to 15thNight
15%12%47%5%45%5%5%6%27%
2940
16th to endNight
15%16%6%8%5%3335%5%26%
3136

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%6%8%7%3436%10%25%
1672
16th to endDay
8%10%6%11%8%47%5%6%8%20%
1841
February1st to 15thDay
9%10%5%7%6%25%45%8%33%
1845
16th to endDay
11%12%47%6%3445%7%31%
1722
March1st to 15thDay
12%7%47%6%3445%6%37%
2201
16th to endDay
15%9%26%5%345%46%34%
2530
April1st to 15thDay
14%8%47%5%44446%35%
2511
16th to endDay
20%8%36%5%3345%6%32%
2645
May1st to 15thDay
18%6%36%5%3445%6%33%
2931
16th to endDay
17%5%25%435%5%5%7%36%
3065
June1st to 15thDay
14%5%244345%6%8%40%
2940
16th to endDay
15%5%25%5%36%5%6%9%34%
3136
July1st to 15thDay
9%314425%5%6%8%46%
2958
16th to endDay
5%314425%5%5%9%50%
2879
August1st to 15thDay
9%4145%25%5%5%9%45%
2587
16th to endDay
12%5%25%42345%8%46%
2594
September1st to 15thDay
8%424445%46%7%47%
2340
16th to endDay
17%6%245%4345%6%39%
2151
October1st to 15thDay
17%6%37%5%25%5%46%35%
1950
16th to endDay
21%8%25%5%24446%32%
1986
November1st to 15thDay
15%9%47%5%35%5%46%31%
1706
16th to endDay
15%12%5%8%6%46%45%7%24%
1680
December1st to 15thDay
13%13%6%10%7%346%6%7%20%
1680
16th to endDay
18%17%6%9%7%34445%17%
1792
January1st to 15thNight
11%10%5%6%6%35%6%6%11%24%
2926
16th to endNight
10%11%6%9%6%45%5%6%8%25%
3083
February1st to 15thNight
8%12%48%6%25%5%47%35%
2668
16th to endNight
10%11%37%6%3436%6%34%
2323
March1st to 15thNight
12%9%36%5%345%45%38%
2430
16th to endNight
14%8%35%5%33445%40%
2398
April1st to 15thNight
17%10%46%5%23446%35%
2097
16th to endNight
20%7%36%425%445%35%
1917
May1st to 15thNight
19%7%25%5%2445%6%35%
1679
16th to endNight
15%5%245%36%5%6%7%37%
1752
June1st to 15thNight
16%6%245%25%45%8%40%
1680
16th to endNight
15%7%24425%47%8%38%
1479
July1st to 15thNight
8%32432445%8%52%
1560
16th to endNight
7%413425%46%9%50%
1641
August1st to 15thNight
9%323323347%56%
1623
16th to endNight
15%413313248%50%
1960
September1st to 15thNight
9%415%333446%53%
1950
16th to endNight
15%5%2442446%6%42%
2126
October1st to 15thNight
17%5%25%425%446%41%
2340
16th to endNight
21%7%25%5%24446%33%
2590
November1st to 15thNight
16%9%35%435%447%34%
2809
16th to endNight
16%9%46%6%25%5%5%6%32%
2940
December1st to 15thNight
15%13%48%7%46%5%5%7%21%
2940
16th to endNight
16%15%7%8%5%245%5%7%20%
3136

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%4435%8%29%
1672
16th to endDay
8%11%5%11%9%37%6%6%8%22%
1841
February1st to 15thDay
9%11%48%6%3435%7%34%
1845
16th to endDay
10%11%6%6%6%345%5%8%29%
1722
March1st to 15thDay
11%8%47%6%3445%7%36%
2201
16th to endDay
16%9%36%5%35%45%6%33%
2528
April1st to 15thDay
14%9%46%6%345%46%34%
2511
16th to endDay
20%8%36%5%3345%6%32%
2645
May1st to 15thDay
18%7%26%6%35%447%32%
2931
16th to endDay
17%5%35%5%35%5%5%8%35%
3065
June1st to 15thDay
14%4245%345%6%8%39%
2940
16th to endDay
15%5%25%5%26%5%7%9%33%
3136
July1st to 15thDay
9%4144345%7%9%45%
2958
16th to endDay
5%414425%5%6%10%49%
2879
August1st to 15thDay
9%4145%345%6%8%44%
2587
16th to endDay
12%426%5%2335%8%44%
2594
September1st to 15thDay
8%4245%45%45%7%47%
2340
16th to endDay
17%6%245%3445%7%37%
2151
October1st to 15thDay
16%7%27%5%35%5%45%34%
1950
16th to endDay
21%9%36%5%34446%32%
1986
November1st to 15thDay
15%10%47%6%35%35%6%31%
1706
16th to endDay
15%12%6%7%6%45%45%7%25%
1680
December1st to 15thDay
12%14%5%9%8%446%5%6%23%
1680
16th to endDay
17%17%6%10%7%3444419%
1792
January1st to 15thNight
11%11%46%6%45%5%5%8%30%
2926
16th to endNight
10%12%5%9%6%35%5%6%8%26%
3083
February1st to 15thNight
8%11%5%8%5%245%37%36%
2668
16th to endNight
11%10%37%6%3436%7%34%
2323
March1st to 15thNight
12%9%36%5%345%5%6%37%
2430
16th to endNight
14%9%36%5%34435%39%
2398
April1st to 15thNight
16%11%36%5%2445%5%35%
2097
16th to endNight
20%8%25%42445%5%34%
1917
May1st to 15thNight
20%7%35%5%23446%35%
1679
16th to endNight
14%5%25%5%35%5%6%7%38%
1752
June1st to 15thNight
15%5%25%5%3345%8%41%
1680
16th to endNight
14%6%24425%5%6%9%38%
1479
July1st to 15thNight
8%31342446%7%54%
1560
16th to endNight
6%3134245%6%9%50%
1641
August1st to 15thNight
9%413322447%55%
1623
16th to endNight
14%5%23313347%50%
1960
September1st to 15thNight
8%424424346%53%
1950
16th to endNight
13%6%2442446%7%42%
2126
October1st to 15thNight
17%5%25%325%45%6%41%
2340
16th to endNight
20%6%25%5%24446%34%
2590
November1st to 15thNight
15%9%35%43446%7%34%
2809
16th to endNight
16%9%36%5%25%5%5%7%32%
2940
December1st to 15thNight
15%13%48%6%35%5%5%7%24%
2940
16th to endNight
16%16%6%8%5%24447%23%
3136

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
55%412%20%6%
1673
16th to endDay
58%7%11%17%5%
1841
February1st to 15thDay
48%6%16%19%8%1
1846
16th to endDay
52%8%12%18%7%
1722
March1st to 15thDay
47%6%14%20%9%
2201
16th to endDay
49%8%13%19%7%1
2530
April1st to 15thDay
50%5%11%18%12%1
2511
16th to endDay
52%6%11%18%9%1
2645
May1st to 15thDay
51%5%13%21%6%1
2931
16th to endDay
45%7%14%21%10%
3069
June1st to 15thDay
40%7%17%24%9%
2940
16th to endDay
43%7%18%21%7%
3136
July1st to 15thDay
31%7%14%26%16%1
2808
16th to endDay
29%10%18%28%12%1
2712
August1st to 15thDay
35%8%16%27%10%1
2572
16th to endDay
37%5%17%26%12%
2594
September1st to 15thDay
33%8%18%31%7%
2340
16th to endDay
45%7%16%24%5%
2151
October1st to 15thDay
49%6%14%21%7%
1950
16th to endDay
53%6%13%18%7%
1986
November1st to 15thDay
53%5%12%19%7%
1706
16th to endDay
60%7%11%13%5%
1680
December1st to 15thDay
61%8%12%14%3
1680
16th to endDay
68%48%13%3
1792
January1st to 15thNight
50%6%14%22%5%
2926
16th to endNight
55%5%14%19%5%
3083
February1st to 15thNight
49%5%15%20%9%
2678
16th to endNight
48%5%12%24%8%
2323
March1st to 15thNight
45%8%12%20%11%
2430
16th to endNight
46%5%12%22%11%1
2398
April1st to 15thNight
50%410%19%13%1
2097
16th to endNight
49%6%8%22%12%
1917
May1st to 15thNight
48%7%12%23%7%
1680
16th to endNight
43%8%10%24%12%1
1754
June1st to 15thNight
41%7%13%23%13%1
1680
16th to endNight
41%7%14%25%9%1
1479
July1st to 15thNight
28%6%14%30%17%2
1482
16th to endNight
27%8%17%28%14%2
1545
August1st to 15thNight
28%5%17%32%12%3
1614
16th to endNight
34%415%27%15%1
1960
September1st to 15thNight
31%5%16%34%10%
1950
16th to endNight
39%7%18%27%7%
2126
October1st to 15thNight
42%5%13%27%10%
2340
16th to endNight
51%6%12%21%7%
2590
November1st to 15thNight
48%6%13%21%8%
2809
16th to endNight
50%7%18%17%5%
2940
December1st to 15thNight
59%6%13%18%2
2940
16th to endNight
60%6%13%15%4
3136

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
20%20%35%20%3
180
16th to endDay
14%10%46%24%4
192
February1st to 15thDay
15%25%43%15%1
180
16th to endDay
18%20%42%11%6%
159
March1st to 15thDay
13%18%37%22%6%1
180
16th to endDay
20%18%32%18%8%2
258
April1st to 15thDay
21%19%32%19%6%
390
16th to endDay
23%20%30%16%6%1
505
May1st to 15thDay
19%20%35%18%41
618
16th to endDay
20%15%28%24%7%3
677
June1st to 15thDay
15%17%33%24%6%2
645
16th to endDay
16%16%31%23%10%2
645
July1st to 15thDay
11%11%30%27%14%3
602
16th to endDay
8%15%31%28%11%5%
595
August1st to 15thDay
12%10%22%34%15%3
549
16th to endDay
17%10%21%31%15%3
506
September1st to 15thDay
11%8%28%31%15%3
375
16th to endDay
26%12%30%18%10%1
286
October1st to 15thDay
26%15%31%19%6%1
180
16th to endDay
26%21%32%16%2
192
November1st to 15thDay
21%17%41%13%6%
180
16th to endDay
27%16%32%20%3
180
December1st to 15thDay
20%14%43%18%2
180
16th to endDay
21%17%39%20%1
192
January1st to 15thNight
15%27%30%21%5%
1050
16th to endNight
14%25%39%15%3
1120
February1st to 15thNight
13%28%33%18%5%
1030
16th to endNight
13%23%31%23%7%
853
March1st to 15thNight
13%24%27%25%7%
750
16th to endNight
15%23%26%20%11%3
672
April1st to 15thNight
20%22%27%23%6%
629
16th to endNight
24%20%22%22%7%1
624
May1st to 15thNight
19%20%26%24%7%2
630
16th to endNight
16%17%20%30%13%1
659
June1st to 15thNight
15%18%22%32%10%
630
16th to endNight
16%17%21%29%13%
630
July1st to 15thNight
10%12%23%32%20%1
588
16th to endNight
7%17%23%31%16%2
612
August1st to 15thNight
12%11%17%30%24%3
575
16th to endNight
15%12%21%28%18%3
621
September1st to 15thNight
10%11%27%27%18%3
585
16th to endNight
16%13%25%27%14%1
670
October1st to 15thNight
20%18%26%24%8%1
780
16th to endNight
23%18%29%22%6%
832
November1st to 15thNight
17%23%28%21%7%
963
16th to endNight
17%28%27%19%6%
1050
December1st to 15thNight
18%28%29%17%4
1050
16th to endNight
20%25%28%17%6%
1120
Page generated at 2019-07-12 06:32:36. Version ac04

Copyright 2019 A. Danko


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