Apple River
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Apple River clear sky chart from 2005-11-05 to 2017-09-10.

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
35%
15992
17%
46784
10%
15949
42%
15949
23%
31249

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
22%
900
13%
2506
4%
895
29%
895
18%
1838
January16th to endNight
18%
960
11%
2595
3%
960
25%
960
16%
1974
February1st to 15thNight
23%
874
13%
2286
3%
874
30%
874
20%
1646
February16th to endNight
23%
631
18%
1893
7%
631
33%
631
18%
1323
March1st to 15thNight
24%
686
14%
2126
7%
686
32%
686
19%
1427
March16th to endNight
26%
576
14%
2019
9%
576
34%
576
16%
1420
April1st to 15thNight
26%
539
16%
1797
10%
539
36%
539
18%
1210
April16th to endNight
32%
540
18%
1794
11%
540
43%
540
20%
1221
May1st to 15thNight
31%
540
15%
1488
6%
540
38%
540
23%
1058
May16th to endNight
42%
563
17%
1497
8%
561
50%
561
32%
963
June1st to 15thNight
51%
540
16%
1440
9%
540
55%
540
34%
921
June16th to endNight
47%
540
16%
1440
8%
540
52%
540
32%
938
July1st to 15thNight
65%
510
18%
1360
11%
510
67%
510
45%
782
July16th to endNight
65%
564
22%
1417
16%
531
68%
531
45%
808
August1st to 15thNight
70%
539
22%
1568
20%
536
73%
536
39%
883
August16th to endNight
64%
573
21%
1910
23%
573
67%
573
32%
1085
September1st to 15thNight
61%
525
26%
1750
26%
525
67%
525
36%
937
September16th to endNight
51%
610
24%
1770
15%
610
58%
610
35%
1032
October1st to 15thNight
42%
660
24%
1980
16%
660
50%
660
30%
1204
October16th to endNight
30%
704
18%
2186
9%
704
40%
704
23%
1424
November1st to 15thNight
33%
700
23%
2276
16%
700
42%
700
25%
1371
November16th to endNight
22%
858
15%
2478
7%
858
31%
858
20%
1718
December1st to 15thNight
19%
900
11%
2520
4%
900
25%
900
15%
1921
December16th to endNight
18%
960
11%
2688
2%
960
26%
960
12%
2145

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
13%8%36%5%3445%7%37%
47852
Night
13%7%36%424447%40%
46952
Cloud CoverDay
13%8%36%5%3445%7%36%
47860
Night
13%7%36%5%34447%40%
46957
TransparencyDay
46%6%13%21%11%1
47537
Night
43%5%12%22%13%1
46785
SeeingDay
16%9%30%25%13%4
6002
Night
17%9%31%28%11%1
15996

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
11%12%6%7%6%36%45%6%29%
1432
16th to endDay
11%14%6%11%6%35%336%25%
1626
February1st to 15thDay
13%13%6%8%5%34436%30%
1575
16th to endDay
13%11%37%6%34345%34%
1580
March1st to 15thDay
15%10%46%424347%36%
1835
16th to endDay
17%11%45%6%3345%6%32%
2204
April1st to 15thDay
17%9%46%5%345%5%6%30%
2151
16th to endDay
22%7%35%433445%33%
2166
May1st to 15thDay
18%9%36%6%35%5%5%6%29%
2460
16th to endDay
14%5%36%5%345%6%7%36%
2617
June1st to 15thDay
13%5%35%435%5%6%7%38%
2520
16th to endDay
10%5%25%5%35%5%6%9%40%
2520
July1st to 15thDay
6%324435%5%6%10%45%
2520
16th to endDay
8%426%6%45%6%6%9%39%
2655
August1st to 15thDay
6%5%25%5%36%6%6%9%41%
2381
16th to endDay
12%6%245%25%5%5%7%44%
2292
September1st to 15thDay
13%413433348%49%
2097
16th to endDay
13%6%3442435%7%44%
1848
October1st to 15thDay
14%7%25%323335%46%
1650
16th to endDay
17%6%36%423445%39%
1686
November1st to 15thDay
11%8%36%5%3445%6%40%
1582
16th to endDay
15%10%46%5%33335%37%
1479
December1st to 15thDay
17%12%5%8%6%34335%28%
1440
16th to endDay
19%16%5%9%5%23445%22%
1536
January1st to 15thNight
13%11%47%6%3445%5%33%
2506
16th to endNight
10%11%6%10%7%34447%28%
2595
February1st to 15thNight
11%10%5%8%5%24446%36%
2283
16th to endNight
14%9%37%5%34345%37%
1893
March1st to 15thNight
15%10%35%424346%38%
2113
16th to endNight
18%9%36%5%35%347%33%
2019
April1st to 15thNight
18%7%44433446%37%
1797
16th to endNight
19%7%25%433445%37%
1794
May1st to 15thNight
17%5%25%5%35%5%5%9%33%
1488
16th to endNight
11%424325%46%10%43%
1496
June1st to 15thNight
12%425%41445%8%46%
1440
16th to endNight
10%4245%25%5%6%9%43%
1440
July1st to 15thNight
6%21222346%11%55%
1440
16th to endNight
6%21342346%10%53%
1513
August1st to 15thNight
5%2245%345%5%9%52%
1577
16th to endNight
8%42442435%6%52%
1910
September1st to 15thNight
9%314323446%57%
1750
16th to endNight
9%32442446%8%49%
1770
October1st to 15thNight
12%425%423346%50%
1980
16th to endNight
16%6%25%434346%42%
2186
November1st to 15thNight
11%7%26%423345%49%
2276
16th to endNight
16%9%36%434346%38%
2478
December1st to 15thNight
18%11%49%5%35%435%28%
2520
16th to endNight
21%12%5%8%6%34435%23%
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
11%12%5%8%6%45%5%5%6%28%
1432
16th to endDay
11%13%7%11%6%25%346%25%
1626
February1st to 15thDay
13%13%6%8%5%35%436%30%
1575
16th to endDay
13%10%47%6%34336%34%
1580
March1st to 15thDay
15%11%36%423447%35%
1845
16th to endDay
17%11%35%6%34446%31%
2202
April1st to 15thDay
17%9%46%5%345%5%7%30%
2151
16th to endDay
21%8%36%433445%33%
2166
May1st to 15thDay
17%9%47%6%35%5%5%7%28%
2460
16th to endDay
13%6%36%5%36%5%5%7%36%
2617
June1st to 15thDay
13%5%36%5%346%6%7%38%
2520
16th to endDay
9%5%25%5%36%6%5%9%40%
2520
July1st to 15thDay
6%4245%35%6%6%10%45%
2520
16th to endDay
7%425%6%45%5%7%9%39%
2655
August1st to 15thDay
6%5%26%5%35%7%7%9%40%
2381
16th to endDay
11%5%245%25%46%7%43%
2292
September1st to 15thDay
12%414424348%48%
2097
16th to endDay
11%7%2442435%8%44%
1848
October1st to 15thDay
14%7%34423435%46%
1650
16th to endDay
17%7%35%423446%39%
1686
November1st to 15thDay
11%8%36%6%24446%40%
1582
16th to endDay
15%10%5%5%6%23335%37%
1479
December1st to 15thDay
18%12%5%8%5%34335%28%
1440
16th to endDay
19%15%6%10%5%2345%5%22%
1536
January1st to 15thNight
12%11%5%7%5%4445%6%33%
2506
16th to endNight
10%11%7%10%7%35%45%6%28%
2595
February1st to 15thNight
11%11%48%5%24445%36%
2276
16th to endNight
13%10%37%6%24346%37%
1893
March1st to 15thNight
15%10%35%425%436%37%
2126
16th to endNight
17%9%46%5%35%338%32%
2019
April1st to 15thNight
17%8%35%434446%37%
1797
16th to endNight
18%8%36%434346%37%
1794
May1st to 15thNight
17%5%26%5%35%5%5%8%33%
1487
16th to endNight
10%425%325%46%10%43%
1496
June1st to 15thNight
12%425%32446%8%45%
1440
16th to endNight
10%424425%5%7%9%42%
1440
July1st to 15thNight
6%21222346%11%55%
1440
16th to endNight
6%3342346%11%52%
1513
August1st to 15thNight
5%2245%3445%9%52%
1577
16th to endNight
7%5%24434346%52%
1910
September1st to 15thNight
8%324323446%57%
1750
16th to endNight
8%424425%46%7%50%
1770
October1st to 15thNight
11%5%2443335%6%49%
1980
16th to endNight
16%6%24433346%42%
2186
November1st to 15thNight
10%7%25%423445%48%
2276
16th to endNight
16%8%36%5%25%336%37%
2478
December1st to 15thNight
18%11%49%5%34445%28%
2520
16th to endNight
21%13%5%9%6%34445%23%
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%5%15%15%9%
1433
16th to endDay
59%6%14%13%6%
1626
February1st to 15thDay
56%312%19%7%
1576
16th to endDay
51%6%10%21%8%1
1580
March1st to 15thDay
48%5%15%20%8%
1845
16th to endDay
53%6%12%19%7%
2204
April1st to 15thDay
53%6%10%21%8%
2151
16th to endDay
52%6%9%18%11%1
2166
May1st to 15thDay
53%6%13%18%7%
2460
16th to endDay
46%7%11%19%13%1
2621
June1st to 15thDay
43%8%12%21%14%
2520
16th to endDay
38%8%14%23%13%1
2520
July1st to 15thDay
34%9%15%24%13%1
2371
16th to endDay
37%9%16%21%11%2
2488
August1st to 15thDay
36%8%14%25%13%1
2366
16th to endDay
38%7%12%25%13%2
2292
September1st to 15thDay
35%5%9%30%17%1
2097
16th to endDay
38%5%12%27%14%
1848
October1st to 15thDay
41%410%26%16%
1650
16th to endDay
45%5%13%24%10%1
1686
November1st to 15thDay
43%5%12%24%11%2
1582
16th to endDay
50%419%20%5%
1479
December1st to 15thDay
58%5%12%16%6%
1440
16th to endDay
64%5%12%10%7%
1536
January1st to 15thNight
52%5%12%18%10%
2506
16th to endNight
56%415%14%8%
2595
February1st to 15thNight
49%5%13%19%10%1
2286
16th to endNight
49%5%12%22%8%2
1893
March1st to 15thNight
48%413%19%12%1
2126
16th to endNight
52%5%12%21%7%1
2019
April1st to 15thNight
48%49%21%13%1
1797
16th to endNight
48%49%20%13%3
1794
May1st to 15thNight
46%7%15%18%11%
1488
16th to endNight
34%9%15%22%16%1
1498
June1st to 15thNight
33%7%12%25%19%1
1440
16th to endNight
35%8%12%21%18%3
1440
July1st to 15thNight
23%7%14%32%18%3
1360
16th to endNight
25%5%18%27%19%2
1417
August1st to 15thNight
27%6%14%30%19%1
1568
16th to endNight
31%6%12%28%16%4
1910
September1st to 15thNight
28%410%27%27%1
1750
16th to endNight
30%5%13%31%16%2
1770
October1st to 15thNight
36%410%25%21%2
1980
16th to endNight
43%413%24%12%1
2186
November1st to 15thNight
37%5%12%23%17%3
2276
16th to endNight
48%414%22%9%
2478
December1st to 15thNight
58%411%18%6%
2520
16th to endNight
64%411%12%5%1
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
24%14%38%17%4
90
16th to endDay
22%14%32%20%8%1
96
February1st to 15thDay
22%24%34%13%5%
90
16th to endDay
24%22%29%19%21
81
March1st to 15thDay
30%15%42%10%2
90
16th to endDay
29%12%29%19%6%2
188
April1st to 15thDay
24%13%32%21%8%
270
16th to endDay
24%11%28%21%11%2
270
May1st to 15thDay
21%14%33%21%6%2
417
16th to endDay
17%12%33%22%10%3
517
June1st to 15thDay
14%8%31%27%14%3
495
16th to endDay
11%9%36%24%13%4
495
July1st to 15thDay
8%429%30%16%10%
475
16th to endDay
10%329%30%18%8%
515
August1st to 15thDay
7%223%34%23%7%
484
16th to endDay
15%5%18%28%21%10%
332
September1st to 15thDay
12%421%32%21%7%
294
16th to endDay
14%8%25%23%23%5%
251
October1st to 15thDay
10%14%31%26%15%2
90
16th to endDay
23%14%35%22%3
96
November1st to 15thDay
7%14%30%27%14%5%
90
16th to endDay
33%15%38%6%5%
90
December1st to 15thDay
25%20%34%15%4
90
16th to endDay
28%28%36%7%
96
January1st to 15thNight
17%15%38%21%6%
900
16th to endNight
18%13%40%24%3
960
February1st to 15thNight
17%14%37%25%5%
878
16th to endNight
20%13%36%23%4
631
March1st to 15thNight
22%12%34%24%5%
686
16th to endNight
23%10%35%23%7%
576
April1st to 15thNight
22%13%33%25%5%
539
16th to endNight
23%10%29%28%8%
540
May1st to 15thNight
18%6%38%26%8%
540
16th to endNight
13%434%35%12%
563
June1st to 15thNight
14%426%44%11%
540
16th to endNight
11%430%37%15%
540
July1st to 15thNight
8%120%39%27%2
510
16th to endNight
7%120%42%26%2
564
August1st to 15thNight
5%113%45%29%3
539
16th to endNight
11%216%39%26%4
573
September1st to 15thNight
8%420%36%23%6%
525
16th to endNight
11%7%25%31%22%2
610
October1st to 15thNight
14%7%30%30%15%1
660
16th to endNight
19%13%32%26%7%
704
November1st to 15thNight
15%12%34%26%9%
700
16th to endNight
20%14%37%19%7%
858
December1st to 15thNight
24%14%36%20%4
900
16th to endNight
26%11%34%22%3
960
Page generated at 2017-09-11 18:35:23. Version ac04

Copyright 2017 A. Danko


Apple River Clear Sky Chart | Charts Home