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 2017-03-24.

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
37%
15136
16%
45548
11%
15099
42%
15099
19%
32539

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
28%
720
15%
1499
March16th to endNight
25%
740
14%
2035
8%
740
30%
740
17%
1527
April1st to 15thNight
25%
658
15%
1723
6%
658
32%
658
20%
1250
April16th to endNight
38%
545
18%
1535
10%
545
43%
545
25%
1046
May1st to 15thNight
37%
495
13%
1485
7%
495
42%
495
17%
1092
May16th to endNight
50%
513
15%
1540
11%
513
53%
513
25%
1035
June1st to 15thNight
59%
495
15%
1485
12%
495
62%
495
26%
982
June16th to endNight
60%
495
14%
1485
13%
495
62%
495
29%
947
July1st to 15thNight
57%
465
12%
1395
12%
465
57%
465
23%
976
July16th to endNight
68%
522
12%
1469
12%
489
69%
489
30%
910
August1st to 15thNight
65%
494
19%
1474
16%
491
66%
491
27%
966
August16th to endNight
69%
588
22%
1638
18%
588
70%
588
35%
1009
September1st to 15thNight
59%
660
23%
1741
16%
660
61%
660
32%
1133
September16th to endNight
55%
657
25%
1815
20%
657
58%
657
30%
1172
October1st to 15thNight
49%
660
24%
1961
21%
660
55%
660
27%
1258
October16th to endNight
34%
704
20%
2112
15%
704
43%
704
20%
1452
November1st to 15thNight
41%
700
23%
2191
18%
700
47%
700
24%
1421
November16th to endNight
28%
720
16%
2412
11%
720
36%
720
14%
1723
December1st to 15thNight
21%
720
8%
2520
6%
720
26%
720
8%
2023
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%31%
45369
Night
18%9%36%42445%6%33%
45741
Cloud CoverDay
18%9%36%5%3445%6%31%
45379
Night
17%9%36%5%2445%6%34%
45745
TransparencyDay
52%6%9%18%11%1
45080
Night
51%5%10%18%12%1
45548
SeeingDay
25%9%19%21%16%7%
4798
Night
25%10%21%26%14%2
15144

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%43435%6%28%
2034
April1st to 15thDay
18%10%45%423347%36%
1895
16th to endDay
18%6%35%435%45%6%35%
2104
May1st to 15thDay
22%6%36%5%36%5%5%7%25%
2136
16th to endDay
16%5%35%5%45%45%6%35%
2223
June1st to 15thDay
14%6%25%5%35%6%6%9%33%
2145
16th to endDay
14%5%36%6%46%5%7%8%31%
2145
July1st to 15thDay
16%6%26%7%35%6%5%8%31%
2145
16th to endDay
14%435%6%46%7%7%9%30%
2283
August1st to 15thDay
13%6%36%6%5%6%6%7%8%28%
2145
16th to endDay
12%5%25%5%45%6%7%9%35%
2201
September1st to 15thDay
15%5%15%425%46%8%39%
1888
16th to endDay
17%7%34434446%39%
1815
October1st to 15thDay
21%7%2432235%7%39%
1669
16th to endDay
22%7%15%324435%38%
1760
November1st to 15thDay
15%8%24424445%42%
1665
16th to endDay
20%12%25%324446%32%
1545
December1st to 15thDay
27%14%5%7%5%2334422%
1440
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%34323345%32%
2035
April1st to 15thNight
18%9%45%42445%6%34%
1723
16th to endNight
15%5%25%5%335%5%7%39%
1535
May1st to 15thNight
19%7%35%5%346%5%7%30%
1485
16th to endNight
13%5%346%3445%7%41%
1538
June1st to 15thNight
10%435%435%5%6%9%40%
1485
16th to endNight
9%5%234345%7%10%42%
1485
July1st to 15thNight
13%5%36%5%35%5%5%10%35%
1485
16th to endNight
8%325%436%6%9%11%39%
1577
August1st to 15thNight
9%425%446%6%7%10%37%
1485
16th to endNight
10%4234245%5%8%47%
1638
September1st to 15thNight
12%5%1442445%7%45%
1741
16th to endNight
15%5%24325%346%46%
1815
October1st to 15thNight
16%415%5%23447%44%
1961
16th to endNight
22%7%25%42434438%
2112
November1st to 15thNight
19%9%24323345%42%
2191
16th to endNight
19%11%45%43345%5%32%
2412
December1st to 15thNight
23%15%6%10%424335%20%
2520
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%
2033
April1st to 15thDay
18%10%45%423437%36%
1895
16th to endDay
18%6%345%35%45%6%35%
2104
May1st to 15thDay
23%6%36%6%36%45%7%25%
2136
16th to endDay
16%5%36%5%45%45%6%35%
2223
June1st to 15thDay
14%5%25%5%36%6%6%8%34%
2145
16th to endDay
14%5%36%6%45%6%7%8%31%
2145
July1st to 15thDay
16%6%26%6%35%7%48%31%
2145
16th to endDay
14%5%25%6%47%6%7%9%30%
2283
August1st to 15thDay
13%6%46%7%46%6%7%8%28%
2145
16th to endDay
13%5%15%5%35%6%7%9%35%
2201
September1st to 15thDay
15%5%24425%5%5%8%39%
1888
16th to endDay
18%7%3442445%6%39%
1815
October1st to 15thDay
21%6%2442235%6%40%
1669
16th to endDay
22%7%25%423435%38%
1760
November1st to 15thDay
16%8%24424445%42%
1665
16th to endDay
19%12%35%324346%32%
1545
December1st to 15thDay
26%14%47%5%2343422%
1440
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%32%
2035
April1st to 15thNight
18%9%45%424446%34%
1723
16th to endNight
15%6%25%5%335%5%7%39%
1535
May1st to 15thNight
20%6%36%5%35%45%7%31%
1484
16th to endNight
14%5%25%6%335%5%8%40%
1538
June1st to 15thNight
10%434435%5%7%9%40%
1485
16th to endNight
9%5%23325%5%7%10%42%
1485
July1st to 15thNight
12%6%36%5%35%46%9%35%
1485
16th to endNight
8%425%426%5%9%10%40%
1577
August1st to 15thNight
9%425%5%45%6%7%10%37%
1485
16th to endNight
10%42443446%8%47%
1638
September1st to 15thNight
13%5%23425%45%6%45%
1741
16th to endNight
16%5%23325%346%46%
1815
October1st to 15thNight
16%415%5%23447%44%
1961
16th to endNight
22%6%24424445%38%
2112
November1st to 15thNight
19%8%24313335%42%
2191
16th to endNight
18%12%46%434445%32%
2412
December1st to 15thNight
24%15%5%9%5%33335%20%
2520
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
57%5%7%18%9%1
2034
April1st to 15thDay
48%410%18%15%2
1895
16th to endDay
48%6%8%17%14%4
2104
May1st to 15thDay
57%8%9%16%7%1
2136
16th to endDay
49%7%12%20%8%1
2227
June1st to 15thDay
44%9%13%20%12%
2145
16th to endDay
48%8%13%17%11%
2145
July1st to 15thDay
49%7%10%17%11%3
2006
16th to endDay
46%9%11%19%10%2
2128
August1st to 15thDay
50%7%12%19%9%
2132
16th to endDay
43%8%13%23%9%1
2201
September1st to 15thDay
41%6%10%20%18%2
1888
16th to endDay
45%5%6%23%17%1
1815
October1st to 15thDay
44%6%9%23%14%1
1669
16th to endDay
49%49%22%13%1
1760
November1st to 15thDay
44%46%21%18%4
1665
16th to endDay
52%5%8%18%14%
1545
December1st to 15thDay
65%36%15%7%1
1440
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%12%
2035
April1st to 15thNight
50%49%17%14%2
1723
16th to endNight
44%412%15%16%6%
1535
May1st to 15thNight
52%7%11%16%11%1
1485
16th to endNight
42%8%13%25%9%1
1540
June1st to 15thNight
39%9%14%22%13%
1485
16th to endNight
35%9%15%22%15%1
1485
July1st to 15thNight
44%8%12%17%14%2
1395
16th to endNight
33%9%18%22%13%2
1469
August1st to 15thNight
38%9%15%21%13%1
1474
16th to endNight
34%5%12%28%15%2
1638
September1st to 15thNight
37%6%13%17%22%2
1741
16th to endNight
39%5%8%25%21%
1815
October1st to 15thNight
39%5%9%24%17%2
1961
16th to endNight
48%46%22%16%1
2112
November1st to 15thNight
44%38%16%18%7%
2191
16th to endNight
53%5%7%16%15%1
2412
December1st to 15thNight
68%47%11%7%1
2520
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
33%15%24%15%8%1
260
April1st to 15thDay
25%13%27%21%10%1
210
16th to endDay
24%10%20%22%13%8%
210
May1st to 15thDay
29%11%23%13%14%6%
228
16th to endDay
22%6%15%22%21%11%
267
June1st to 15thDay
19%420%23%21%10%
255
16th to endDay
22%5%21%23%19%8%
255
July1st to 15thDay
28%5%15%22%16%11%
245
16th to endDay
16%213%24%21%20%
270
August1st to 15thDay
18%113%28%21%16%
253
16th to endDay
18%17%28%23%19%
268
September1st to 15thDay
15%5%8%26%30%14%
255
16th to endDay
21%318%22%26%7%
254
October1st to 15thDay
25%7%18%21%20%6%
255
16th to endDay
23%11%25%24%13%1
272
November1st to 15thDay
25%6%18%28%17%3
173
16th to endDay
35%22%20%14%6%1
77
December1st to 15thDay
40%18%20%15%33
60
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%19%7%1
740
April1st to 15thNight
25%15%30%21%6%
658
16th to endNight
20%10%26%27%14%1
545
May1st to 15thNight
22%10%22%30%11%1
495
16th to endNight
16%221%30%21%6%
515
June1st to 15thNight
12%217%38%25%3
495
16th to endNight
14%217%39%23%2
495
July1st to 15thNight
16%411%39%23%3
465
16th to endNight
12%19%31%34%9%
522
August1st to 15thNight
13%19%37%33%3
494
16th to endNight
12%19%35%33%7%
588
September1st to 15thNight
15%214%30%33%4
660
16th to endNight
17%417%28%29%2
657
October1st to 15thNight
20%5%18%29%21%4
660
16th to endNight
28%10%21%24%12%1
704
November1st to 15thNight
26%8%20%26%16%1
700
16th to endNight
28%15%22%23%7%1
720
December1st to 15thNight
35%17%20%21%5%
720
16th to endNight
33%15%25%22%2
768
Page generated at 2017-03-25 12:39:50. Version ac04

Copyright 2017 A. Danko


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