Elk River WMA
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Elk River WMA clear sky chart from 2005-11-05 to 2017-12-02.

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
38%
16014
16%
48124
11%
15977
43%
15977
19%
34230

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
15%
716
11%
2327
6%
716
22%
716
8%
1886
January16th to endNight
16%
768
12%
2496
7%
768
23%
768
10%
1966
February1st to 15thNight
19%
702
10%
2287
6%
701
25%
701
11%
1763
February16th to endNight
13%
631
11%
1904
4%
631
21%
631
10%
1508
March1st to 15thNight
23%
720
14%
1980
8%
720
29%
720
15%
1499
March16th to endNight
25%
768
14%
2112
8%
768
29%
768
16%
1590
April1st to 15thNight
26%
718
14%
1880
6%
718
33%
718
21%
1359
April16th to endNight
36%
594
18%
1674
9%
594
41%
594
25%
1139
May1st to 15thNight
37%
540
12%
1620
7%
540
42%
540
17%
1196
May16th to endNight
49%
561
14%
1684
11%
561
53%
561
23%
1147
June1st to 15thNight
60%
540
14%
1620
11%
540
63%
540
27%
1055
June16th to endNight
59%
540
16%
1620
13%
540
62%
540
29%
1034
July1st to 15thNight
56%
510
11%
1530
11%
510
57%
510
23%
1067
July16th to endNight
68%
564
14%
1595
14%
531
70%
531
30%
983
August1st to 15thNight
64%
539
18%
1609
14%
536
65%
536
26%
1061
August16th to endNight
69%
642
24%
1788
19%
642
70%
642
36%
1086
September1st to 15thNight
56%
720
22%
1899
15%
720
59%
720
31%
1245
September16th to endNight
57%
717
26%
1980
22%
717
60%
717
31%
1265
October1st to 15thNight
51%
720
24%
2139
21%
720
57%
720
28%
1367
October16th to endNight
35%
768
22%
2304
16%
768
43%
768
20%
1576
November1st to 15thNight
40%
760
22%
2379
18%
760
46%
760
23%
1568
November16th to endNight
28%
780
18%
2613
12%
780
37%
780
15%
1838
December1st to 15thNight
21%
728
8%
2546
6%
728
26%
728
8%
2037
December16th to endNight
19%
768
12%
2538
6%
768
27%
768
10%
1995

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
18%9%36%5%3445%6%32%
48308
Night
17%9%36%5%2445%6%34%
48317
Cloud CoverDay
18%8%36%5%3445%6%32%
48318
Night
17%9%36%5%2445%6%34%
48321
TransparencyDay
51%6%9%19%11%1
48019
Night
50%5%10%18%12%1
48124
SeeingDay
25%9%20%21%15%7%
5768
Night
24%10%21%26%14%2
16022

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
21%14%7%11%7%3422419%
1611
16th to endDay
23%17%7%7%5%2323323%
1728
February1st to 15thDay
20%14%6%8%6%34345%23%
1575
16th to endDay
20%16%5%9%42334425%
1566
March1st to 15thDay
20%12%5%5%423445%32%
1969
16th to endDay
22%11%36%5%3435%6%27%
2112
April1st to 15thDay
18%9%44323447%36%
2068
16th to endDay
19%7%35%435%46%7%34%
2296
May1st to 15thDay
23%6%36%5%36%5%5%7%25%
2331
16th to endDay
16%6%35%5%45%46%6%34%
2431
June1st to 15thDay
13%5%25%5%35%6%6%9%36%
2340
16th to endDay
13%5%36%6%46%5%7%8%32%
2340
July1st to 15thDay
15%7%26%7%35%6%5%8%31%
2340
16th to endDay
15%435%5%46%6%7%10%31%
2465
August1st to 15thDay
13%6%36%6%5%6%6%7%8%28%
2340
16th to endDay
11%5%25%5%45%6%7%9%36%
2402
September1st to 15thDay
15%5%15%435%45%8%39%
2059
16th to endDay
16%7%34433446%40%
1980
October1st to 15thDay
20%7%1432235%7%41%
1821
16th to endDay
22%7%14323435%40%
1920
November1st to 15thDay
17%8%25%5%14445%39%
1807
16th to endDay
19%12%25%324446%34%
1674
December1st to 15thDay
26%13%5%7%5%2334422%
1451
16th to endDay
24%15%5%6%5%235%45%21%
1682
January1st to 15thNight
23%14%7%8%5%2434420%
2327
16th to endNight
21%17%5%8%5%1333424%
2496
February1st to 15thNight
20%13%5%8%6%2344425%
2285
16th to endNight
19%16%48%6%34345%22%
1904
March1st to 15thNight
22%12%35%5%24345%29%
1968
16th to endNight
25%10%34424345%31%
2112
April1st to 15thNight
18%9%35%42445%6%34%
1880
16th to endNight
15%5%25%5%335%5%7%38%
1674
May1st to 15thNight
20%7%35%5%345%5%6%30%
1620
16th to endNight
14%5%345%3445%7%39%
1682
June1st to 15thNight
10%435%435%6%6%9%41%
1620
16th to endNight
10%5%234345%7%10%42%
1620
July1st to 15thNight
12%5%36%5%35%5%6%10%35%
1620
16th to endNight
8%325%425%5%8%11%40%
1703
August1st to 15thNight
10%425%446%6%7%10%36%
1620
16th to endNight
10%4234245%6%8%48%
1788
September1st to 15thNight
12%5%2442445%7%44%
1899
16th to endNight
14%424325%346%47%
1980
October1st to 15thNight
15%415%5%33447%44%
2139
16th to endNight
22%6%25%42434438%
2304
November1st to 15thNight
19%9%24423335%41%
2379
16th to endNight
18%11%45%43345%5%33%
2613
December1st to 15thNight
23%15%6%10%424335%21%
2546
16th to endNight
21%16%6%6%42344423%
2538

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
21%14%7%11%7%3422419%
1611
16th to endDay
22%17%7%6%5%2332324%
1728
February1st to 15thDay
19%14%6%8%5%34345%23%
1575
16th to endDay
20%17%49%42334325%
1566
March1st to 15thDay
20%12%5%4424445%32%
1980
16th to endDay
22%11%35%5%3435%6%28%
2111
April1st to 15thDay
18%9%34423437%36%
2068
16th to endDay
19%6%35%5%35%45%7%34%
2296
May1st to 15thDay
23%6%36%6%36%45%7%26%
2331
16th to endDay
16%5%36%5%45%46%6%34%
2431
June1st to 15thDay
13%5%25%5%35%6%6%8%36%
2340
16th to endDay
13%5%36%6%45%5%7%9%32%
2340
July1st to 15thDay
15%6%36%6%35%7%5%8%31%
2340
16th to endDay
14%5%25%5%47%5%7%9%32%
2465
August1st to 15thDay
13%6%36%6%46%6%7%8%28%
2340
16th to endDay
12%425%5%35%5%7%9%36%
2402
September1st to 15thDay
15%6%25%435%5%5%7%39%
2059
16th to endDay
17%6%2442445%6%40%
1980
October1st to 15thDay
20%6%1441235%6%41%
1821
16th to endDay
22%7%24323435%40%
1920
November1st to 15thDay
17%8%25%424445%39%
1807
16th to endDay
18%12%34323446%33%
1674
December1st to 15thDay
26%14%47%5%2343422%
1451
16th to endDay
24%15%46%423435%21%
1682
January1st to 15thNight
22%15%7%9%5%2334420%
2327
16th to endNight
21%17%5%8%5%2333425%
2496
February1st to 15thNight
19%14%5%8%6%33435%25%
2278
16th to endNight
20%15%5%8%6%23446%22%
1904
March1st to 15thNight
21%12%35%5%34346%29%
1980
16th to endNight
25%10%35%323345%31%
2112
April1st to 15thNight
18%9%45%424446%35%
1880
16th to endNight
14%6%25%5%345%5%7%38%
1674
May1st to 15thNight
20%7%36%5%45%45%7%30%
1619
16th to endNight
14%5%25%6%335%5%8%39%
1682
June1st to 15thNight
10%434435%5%7%9%41%
1620
16th to endNight
10%5%23325%5%7%9%42%
1620
July1st to 15thNight
12%6%36%5%35%5%6%9%35%
1620
16th to endNight
8%424426%5%9%10%41%
1703
August1st to 15thNight
10%425%5%45%6%7%10%36%
1620
16th to endNight
10%42342446%9%48%
1788
September1st to 15thNight
13%5%235%25%45%7%45%
1899
16th to endNight
14%423335%35%6%46%
1980
October1st to 15thNight
15%4145%23447%44%
2139
16th to endNight
22%6%24424445%39%
2304
November1st to 15thNight
19%8%24313335%41%
2379
16th to endNight
17%12%35%433445%33%
2613
December1st to 15thNight
24%15%5%9%433335%20%
2546
16th to endNight
21%16%6%6%5%2434423%
2538

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
70%37%11%6%
1612
16th to endDay
67%26%15%6%
1728
February1st to 15thDay
64%5%9%15%5%
1577
16th to endDay
63%47%16%7%
1566
March1st to 15thDay
54%410%20%8%1
1980
16th to endDay
58%5%7%18%9%
2112
April1st to 15thDay
48%410%18%15%2
2068
16th to endDay
48%6%9%17%13%3
2296
May1st to 15thDay
56%7%8%16%8%1
2331
16th to endDay
49%6%12%20%8%1
2435
June1st to 15thDay
43%8%13%20%13%
2340
16th to endDay
47%8%12%18%12%1
2340
July1st to 15thDay
49%8%10%16%11%3
2201
16th to endDay
44%8%11%20%11%2
2310
August1st to 15thDay
50%7%12%19%8%
2327
16th to endDay
42%8%14%22%10%1
2402
September1st to 15thDay
42%6%10%20%17%2
2059
16th to endDay
44%5%7%23%17%1
1980
October1st to 15thDay
43%6%9%22%16%2
1821
16th to endDay
48%48%23%14%1
1920
November1st to 15thDay
46%46%20%16%4
1807
16th to endDay
50%5%8%20%13%1
1674
December1st to 15thDay
65%36%15%7%1
1451
16th to endDay
64%5%7%15%6%
1682
January1st to 15thNight
68%47%11%7%1
2327
16th to endNight
64%48%15%6%1
2496
February1st to 15thNight
62%48%16%7%
2287
16th to endNight
64%38%15%7%
1904
March1st to 15thNight
57%49%20%7%
1980
16th to endNight
55%5%9%17%11%
2112
April1st to 15thNight
50%49%19%13%2
1880
16th to endNight
44%413%15%15%5%
1674
May1st to 15thNight
53%7%10%15%11%1
1620
16th to endNight
43%8%12%24%9%1
1684
June1st to 15thNight
37%9%14%23%13%
1620
16th to endNight
35%9%15%22%15%1
1620
July1st to 15thNight
44%8%12%17%14%2
1530
16th to endNight
33%9%17%22%15%1
1595
August1st to 15thNight
39%8%15%21%12%1
1609
16th to endNight
33%5%13%29%15%2
1788
September1st to 15thNight
38%6%13%17%22%2
1899
16th to endNight
38%5%8%25%21%
1980
October1st to 15thNight
39%5%9%23%18%2
2139
16th to endNight
48%46%22%16%1
2304
November1st to 15thNight
45%39%17%17%6%
2379
16th to endNight
52%5%7%17%16%1
2613
December1st to 15thNight
67%47%11%6%1
2546
16th to endNight
64%5%9%15%5%
2538

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
37%26%17%12%41
90
16th to endDay
51%16%22%9%
96
February1st to 15thDay
41%30%18%8%1
90
16th to endDay
34%20%35%9%
96
March1st to 15thDay
32%19%27%13%6%
270
16th to endDay
34%16%25%14%7%1
288
April1st to 15thDay
26%13%27%22%8%1
270
16th to endDay
26%10%25%19%11%6%
270
May1st to 15thDay
34%13%22%12%11%5%
288
16th to endDay
23%8%18%20%19%9%
331
June1st to 15thDay
17%5%21%23%21%11%
315
16th to endDay
19%9%25%21%17%7%
315
July1st to 15thDay
24%5%21%25%14%8%
305
16th to endDay
16%214%25%21%19%
326
August1st to 15thDay
18%116%29%18%15%
313
16th to endDay
15%113%28%22%17%
332
September1st to 15thDay
18%7%11%25%25%12%
315
16th to endDay
18%318%22%25%10%
314
October1st to 15thDay
23%6%19%22%20%7%
315
16th to endDay
23%12%24%22%13%2
336
November1st to 15thDay
28%7%21%25%14%2
225
16th to endDay
31%18%25%14%6%2
116
December1st to 15thDay
38%17%19%15%6%3
63
16th to endDay
44%14%24%12%3
89
January1st to 15thNight
35%20%24%15%3
720
16th to endNight
34%18%26%19%1
768
February1st to 15thNight
31%17%26%22%1
704
16th to endNight
32%21%29%15%1
631
March1st to 15thNight
34%14%23%22%4
720
16th to endNight
33%12%25%20%7%1
768
April1st to 15thNight
26%15%29%21%6%
718
16th to endNight
19%9%28%26%13%1
594
May1st to 15thNight
24%10%22%30%10%1
540
16th to endNight
17%222%30%20%6%
563
June1st to 15thNight
12%216%37%27%3
540
16th to endNight
14%218%39%22%2
540
July1st to 15thNight
16%411%39%23%3
510
16th to endNight
12%19%31%36%9%
564
August1st to 15thNight
14%110%37%32%3
539
16th to endNight
12%19%36%33%7%
642
September1st to 15thNight
15%316%30%30%3
720
16th to endNight
16%416%27%30%4
717
October1st to 15thNight
19%5%17%30%21%4
720
16th to endNight
28%10%21%24%13%1
768
November1st to 15thNight
26%8%21%26%15%1
760
16th to endNight
27%16%23%23%8%1
780
December1st to 15thNight
35%17%20%21%5%
728
16th to endNight
33%15%25%22%2
768
Page generated at 2017-12-03 11:16:43. Version ac04

Copyright 2017 A. Danko


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