Peoria
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Peoria clear sky chart from 2005-11-05 to 2018-02-22.

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%
16642
19%
48906
12%
16598
45%
16598
26%
31719

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
23%
975
16%
2716
6%
970
32%
970
20%
1912
January16th to endNight
20%
1040
15%
2785
4%
1040
29%
1040
19%
2009
February1st to 15thNight
23%
905
14%
2435
4%
904
30%
904
19%
1753
February16th to endNight
22%
659
21%
1977
7%
659
33%
659
21%
1328
March1st to 15thNight
26%
702
16%
2142
8%
702
33%
702
19%
1451
March16th to endNight
27%
576
14%
2007
8%
576
35%
576
18%
1349
April1st to 15thNight
29%
539
18%
1797
12%
539
40%
539
22%
1145
April16th to endNight
35%
540
18%
1800
14%
540
44%
540
21%
1194
May1st to 15thNight
37%
540
17%
1566
11%
540
44%
540
23%
1072
May16th to endNight
48%
563
19%
1497
11%
561
54%
561
31%
984
June1st to 15thNight
55%
540
19%
1440
12%
540
59%
540
39%
876
June16th to endNight
50%
540
18%
1440
10%
540
55%
540
35%
906
July1st to 15thNight
64%
510
18%
1360
13%
510
66%
510
40%
810
July16th to endNight
74%
564
26%
1417
19%
531
78%
531
46%
800
August1st to 15thNight
75%
539
24%
1643
25%
536
77%
536
43%
874
August16th to endNight
67%
573
23%
1910
23%
573
73%
573
36%
1047
September1st to 15thNight
63%
540
29%
1800
29%
540
68%
540
37%
961
September16th to endNight
59%
682
30%
1945
21%
682
65%
682
37%
1124
October1st to 15thNight
48%
720
28%
2130
20%
720
55%
720
33%
1262
October16th to endNight
31%
768
22%
2379
13%
768
41%
768
27%
1463
November1st to 15thNight
31%
760
25%
2471
15%
760
44%
760
26%
1476
November16th to endNight
26%
852
22%
2607
10%
852
38%
852
24%
1659
December1st to 15thNight
23%
975
13%
2730
4%
975
31%
975
20%
1947
December16th to endNight
19%
1040
12%
2912
4%
1040
27%
1040
13%
2317

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%35%5%3445%7%38%
49352
Night
13%7%35%424346%41%
49075
Cloud CoverDay
14%7%35%5%3445%7%38%
49360
Night
13%7%35%424446%41%
49080
TransparencyDay
44%412%22%12%1
49038
Night
42%411%24%14%2
48907
SeeingDay
15%10%26%25%16%5%
6439
Night
17%8%29%30%12%1
16644

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
14%13%5%10%7%35%335%26%
1552
16th to endDay
14%15%6%8%5%33445%28%
1789
February1st to 15thDay
15%12%6%7%6%34345%30%
1757
16th to endDay
14%11%6%7%6%34436%31%
1643
March1st to 15thDay
15%12%47%434445%33%
1818
16th to endDay
17%11%46%5%2445%7%29%
2217
April1st to 15thDay
17%8%45%5%24335%37%
2151
16th to endDay
20%8%35%5%2345%6%35%
2160
May1st to 15thDay
21%7%25%5%33447%32%
2381
16th to endDay
16%5%25%5%35%45%6%37%
2617
June1st to 15thDay
11%425%5%35%45%7%43%
2520
16th to endDay
10%5%25%5%36%5%6%8%40%
2520
July1st to 15thDay
8%4245%36%5%6%10%42%
2520
16th to endDay
6%4246%35%5%7%9%43%
2655
August1st to 15thDay
8%4245%35%46%10%45%
2304
16th to endDay
9%4145%4447%8%45%
2292
September1st to 15thDay
13%42442335%7%49%
2160
16th to endDay
9%4244245%5%7%49%
2001
October1st to 15thDay
17%6%2442234446%
1830
16th to endDay
18%7%25%323336%42%
1844
November1st to 15thDay
17%6%14424446%43%
1717
16th to endDay
18%9%36%323435%40%
1680
December1st to 15thDay
18%10%45%6%36%445%29%
1560
16th to endDay
19%14%5%5%5%34336%27%
1664
January1st to 15thNight
13%10%37%5%44345%36%
2716
16th to endNight
12%11%6%7%5%34345%33%
2785
February1st to 15thNight
14%11%5%7%5%34445%34%
2433
16th to endNight
15%9%46%423335%39%
1977
March1st to 15thNight
15%10%46%424436%36%
2129
16th to endNight
16%8%46%5%25%45%8%33%
2007
April1st to 15thNight
15%8%35%42445%5%41%
1797
16th to endNight
19%6%246%24246%38%
1800
May1st to 15thNight
19%6%35%5%1435%7%37%
1566
16th to endNight
9%426%5%35%5%5%8%43%
1496
June1st to 15thNight
10%5%2342345%7%50%
1440
16th to endNight
8%425%445%45%8%45%
1440
July1st to 15thNight
7%314425%5%6%11%47%
1440
16th to endNight
3323425%5%6%10%52%
1513
August1st to 15thNight
5%21333445%9%55%
1652
16th to endNight
7%31442445%7%54%
1910
September1st to 15thNight
11%31332334457%
1800
16th to endNight
7%4243245%5%8%50%
1945
October1st to 15thNight
12%324324446%50%
2130
16th to endNight
16%6%25%323346%45%
2379
November1st to 15thNight
13%6%34423345%48%
2471
16th to endNight
16%6%345%23347%41%
2607
December1st to 15thNight
19%11%46%423346%34%
2730
16th to endNight
22%14%5%8%5%2423424%
2912

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
14%13%5%10%7%35%346%25%
1552
16th to endDay
14%15%6%8%6%33445%28%
1789
February1st to 15thDay
15%12%6%8%6%25%336%30%
1757
16th to endDay
13%11%5%7%6%25%446%31%
1643
March1st to 15thDay
15%11%47%5%3345%5%33%
1828
16th to endDay
16%10%36%5%3446%7%29%
2215
April1st to 15thDay
17%8%45%6%24436%36%
2151
16th to endDay
20%8%25%5%33446%35%
2160
May1st to 15thDay
20%7%36%5%2435%7%32%
2381
16th to endDay
16%6%25%5%45%45%6%37%
2617
June1st to 15thDay
10%5%35%6%35%447%43%
2520
16th to endDay
10%5%35%5%35%5%6%8%40%
2520
July1st to 15thDay
8%4245%35%6%6%10%43%
2520
16th to endDay
6%3236%45%5%8%9%43%
2655
August1st to 15thDay
7%4245%3446%10%45%
2304
16th to endDay
8%4245%35%47%8%44%
2292
September1st to 15thDay
12%41443335%7%48%
2160
16th to endDay
8%4245%235%5%7%48%
2001
October1st to 15thDay
16%6%34423345%46%
1830
16th to endDay
17%8%25%424336%42%
1844
November1st to 15thDay
17%6%13434446%43%
1717
16th to endDay
17%9%35%332335%40%
1680
December1st to 15thDay
19%9%46%6%36%5%45%29%
1560
16th to endDay
19%13%6%6%5%34436%27%
1664
January1st to 15thNight
13%10%37%6%44345%36%
2716
16th to endNight
12%12%6%7%5%34345%32%
2785
February1st to 15thNight
14%11%5%6%5%34435%34%
2426
16th to endNight
15%9%47%423345%38%
1977
March1st to 15thNight
15%10%46%424446%36%
2142
16th to endNight
16%8%46%5%25%45%8%32%
2007
April1st to 15thNight
15%8%35%42445%5%40%
1797
16th to endNight
19%7%25%6%23346%37%
1800
May1st to 15thNight
18%7%35%42445%7%36%
1565
16th to endNight
9%435%5%36%5%5%8%42%
1496
June1st to 15thNight
10%5%23323447%49%
1440
16th to endNight
8%5%25%5%35%45%8%45%
1440
July1st to 15thNight
6%3234345%6%11%48%
1440
16th to endNight
33134245%6%10%52%
1513
August1st to 15thNight
5%21432445%9%55%
1652
16th to endNight
7%31442445%6%53%
1910
September1st to 15thNight
11%323413335%57%
1800
16th to endNight
7%4244245%5%8%50%
1945
October1st to 15thNight
12%424324346%50%
2130
16th to endNight
16%6%25%32335%5%44%
2379
November1st to 15thNight
13%6%34423435%48%
2471
16th to endNight
16%7%35%423346%41%
2607
December1st to 15thNight
18%11%46%423336%34%
2730
16th to endNight
21%14%6%7%5%3433424%
2912

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
61%39%16%9%
1553
16th to endDay
58%313%17%7%
1789
February1st to 15thDay
56%314%18%5%
1759
16th to endDay
54%412%20%7%
1643
March1st to 15thDay
52%415%21%6%
1828
16th to endDay
52%5%15%20%41
2217
April1st to 15thDay
49%210%23%11%1
2151
16th to endDay
49%411%19%12%2
2160
May1st to 15thDay
50%413%21%8%
2381
16th to endDay
45%6%12%18%15%1
2621
June1st to 15thDay
38%5%11%25%15%2
2520
16th to endDay
39%7%11%21%16%3
2520
July1st to 15thDay
36%6%14%24%15%3
2371
16th to endDay
32%7%17%27%13%1
2488
August1st to 15thDay
32%5%15%27%16%1
2289
16th to endDay
34%6%11%26%17%3
2292
September1st to 15thDay
34%49%24%21%5%
2160
16th to endDay
33%410%29%19%2
2001
October1st to 15thDay
40%38%27%17%2
1830
16th to endDay
44%311%24%13%2
1844
November1st to 15thDay
41%311%24%15%2
1717
16th to endDay
47%212%26%9%
1680
December1st to 15thDay
56%411%19%7%
1560
16th to endDay
59%310%17%7%
1664
January1st to 15thNight
50%311%20%13%
2716
16th to endNight
52%215%21%7%
2785
February1st to 15thNight
51%312%19%9%1
2435
16th to endNight
47%311%26%10%
1977
March1st to 15thNight
49%312%23%9%1
2142
16th to endNight
48%5%14%20%9%1
2007
April1st to 15thNight
44%39%26%13%2
1797
16th to endNight
47%49%21%12%4
1800
May1st to 15thNight
46%5%12%21%14%
1566
16th to endNight
37%6%13%19%18%3
1498
June1st to 15thNight
32%412%27%19%4
1440
16th to endNight
35%413%22%19%4
1440
July1st to 15thNight
30%5%13%29%18%3
1360
16th to endNight
24%5%16%32%18%2
1417
August1st to 15thNight
24%5%13%32%20%3
1643
16th to endNight
29%5%10%28%20%5%
1910
September1st to 15thNight
30%37%28%24%5%
1800
16th to endNight
29%5%10%28%22%3
1945
October1st to 15thNight
34%38%26%21%4
2130
16th to endNight
40%210%25%18%2
2379
November1st to 15thNight
38%39%24%18%4
2471
16th to endNight
43%211%28%13%
2607
December1st to 15thNight
52%213%20%9%
2730
16th to endNight
64%38%15%7%
2912

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
30%18%28%20%2
135
16th to endDay
13%29%38%11%6%
144
February1st to 15thDay
22%24%40%9%2
135
16th to endDay
25%22%27%18%8%
100
March1st to 15thDay
32%26%31%7%2
90
16th to endDay
23%15%25%24%8%1
201
April1st to 15thDay
16%13%35%25%8%
270
16th to endDay
22%9%28%21%14%2
270
May1st to 15thDay
23%13%29%21%8%4
345
16th to endDay
19%10%28%23%11%6%
517
June1st to 15thDay
10%5%30%28%21%3
495
16th to endDay
13%7%31%27%15%5%
495
July1st to 15thDay
12%322%31%17%11%
475
16th to endDay
6%117%36%29%8%
515
August1st to 15thDay
8%217%31%28%12%
433
16th to endDay
9%115%29%31%12%
332
September1st to 15thDay
12%414%32%30%6%
315
16th to endDay
8%7%14%32%28%7%
314
October1st to 15thDay
20%12%24%27%12%3
165
16th to endDay
24%12%36%22%4
144
November1st to 15thDay
13%12%33%22%15%2
135
16th to endDay
28%17%37%14%2
135
December1st to 15thDay
17%31%28%16%5%2
135
16th to endDay
27%29%36%6%
144
January1st to 15thNight
18%14%38%22%5%
975
16th to endNight
18%13%38%25%3
1040
February1st to 15thNight
20%11%36%26%4
907
16th to endNight
21%13%38%24%2
659
March1st to 15thNight
21%10%37%24%6%
702
16th to endNight
19%10%36%24%9%
576
April1st to 15thNight
18%13%34%25%7%
539
16th to endNight
21%9%28%28%11%
540
May1st to 15thNight
22%6%27%34%8%
540
16th to endNight
11%329%38%15%1
563
June1st to 15thNight
12%222%46%14%
540
16th to endNight
9%228%39%18%1
540
July1st to 15thNight
7%219%40%28%2
510
16th to endNight
5%110%44%34%2
564
August1st to 15thNight
6%19%46%29%7%
539
16th to endNight
8%15%38%33%3
573
September1st to 15thNight
13%214%36%28%4
540
16th to endNight
8%419%35%26%4
682
October1st to 15thNight
14%6%26%33%17%2
720
16th to endNight
20%10%33%25%8%
768
November1st to 15thNight
17%9%36%26%10%
760
16th to endNight
19%14%34%24%6%
852
December1st to 15thNight
24%13%32%23%6%
975
16th to endNight
30%10%31%24%2
1040
Page generated at 2018-02-23 10:21:29. Version ac04

Copyright 2018 A. Danko


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