England/Idlewild Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the England/Idlewild Park clear sky chart from 2005-11-05 to 2018-10-08.

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
44%
16981
19%
50866
14%
16938
49%
16938
25%
33247

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%
956
14%
2697
6%
951
29%
951
14%
2070
January16th to endNight
22%
832
15%
2704
8%
832
31%
832
14%
1955
February1st to 15thNight
22%
762
13%
2334
6%
761
29%
761
16%
1674
February16th to endNight
22%
683
14%
2049
8%
683
29%
683
16%
1484
March1st to 15thNight
29%
780
17%
2275
11%
780
35%
780
19%
1573
March16th to endNight
33%
832
17%
2288
9%
832
39%
832
22%
1587
April1st to 15thNight
36%
607
19%
1970
13%
607
46%
607
23%
1287
April16th to endNight
41%
579
21%
1774
12%
579
50%
579
26%
1136
May1st to 15thNight
42%
585
16%
1755
10%
585
47%
585
24%
1183
May16th to endNight
58%
610
17%
1828
13%
609
61%
609
30%
1133
June1st to 15thNight
66%
585
20%
1676
16%
585
70%
585
40%
952
June16th to endNight
65%
585
19%
1560
14%
585
68%
585
39%
933
July1st to 15thNight
65%
555
19%
1480
16%
555
67%
555
37%
916
July16th to endNight
71%
612
20%
1722
17%
579
74%
579
36%
982
August1st to 15thNight
73%
575
24%
1715
21%
572
75%
572
37%
983
August16th to endNight
77%
621
24%
2010
26%
621
78%
621
41%
1051
September1st to 15thNight
66%
708
27%
2073
25%
708
68%
708
36%
1210
September16th to endNight
59%
777
29%
2145
23%
777
62%
777
35%
1302
October1st to 15thNight
59%
752
30%
2098
25%
752
64%
752
38%
1208
October16th to endNight
42%
768
25%
2403
20%
768
50%
768
26%
1514
November1st to 15thNight
45%
760
26%
2471
22%
760
53%
760
28%
1477
November16th to endNight
34%
780
21%
2535
15%
780
42%
780
20%
1671
December1st to 15thNight
27%
780
13%
2535
8%
780
33%
780
15%
1844
December16th to endNight
20%
897
13%
2769
6%
897
28%
897
13%
2122

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
15%7%36%5%3445%7%37%
52251
Night
14%7%35%5%2445%7%39%
51047
Cloud CoverDay
14%7%36%5%3445%7%37%
52260
Night
14%7%35%42445%7%39%
51052
TransparencyDay
46%310%22%14%2
51950
Night
44%310%23%15%2
50866
SeeingDay
17%5%21%24%19%11%
7084
Night
19%6%22%30%18%2
16984

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
19%11%410%5%23435%27%
1565
16th to endDay
14%13%5%8%5%45%435%30%
1872
February1st to 15thDay
17%11%5%8%424345%31%
1855
16th to endDay
17%13%5%8%5%2434430%
1710
March1st to 15thDay
22%8%35%42335%434%
2005
16th to endDay
20%10%36%5%34445%31%
2288
April1st to 15thDay
18%7%35%423446%37%
2318
16th to endDay
17%6%25%5%24346%39%
2459
May1st to 15thDay
21%6%25%6%3445%5%33%
2526
16th to endDay
11%6%36%7%45%6%5%8%34%
2639
June1st to 15thDay
11%315%5%35%6%5%8%42%
2610
16th to endDay
9%425%5%46%5%6%8%41%
2730
July1st to 15thDay
11%5%26%5%35%5%6%8%38%
2730
16th to endDay
9%4245%46%6%6%10%38%
2689
August1st to 15thDay
6%5%25%6%35%5%6%9%42%
2487
16th to endDay
8%415%436%5%6%10%42%
2542
September1st to 15thDay
14%425%43446%6%43%
2204
16th to endDay
15%5%24423347%46%
2145
October1st to 15thDay
12%425%6%3445%5%45%
2032
16th to endDay
17%7%25%423346%42%
1818
November1st to 15thDay
11%6%36%424335%48%
1717
16th to endDay
16%9%45%423346%38%
1755
December1st to 15thDay
22%10%47%5%2444427%
1755
16th to endDay
22%13%5%6%6%24335%26%
1800
January1st to 15thNight
19%11%5%9%7%4443427%
2697
16th to endNight
17%13%5%7%5%3433430%
2704
February1st to 15thNight
19%11%48%5%23345%31%
2332
16th to endNight
19%12%47%5%2345%6%28%
2049
March1st to 15thNight
18%9%36%5%34346%34%
2262
16th to endNight
18%7%25%5%245%47%35%
2288
April1st to 15thNight
16%7%45%42445%6%39%
1970
16th to endNight
14%7%35%5%34447%40%
1774
May1st to 15thNight
18%5%25%5%2345%8%36%
1755
16th to endNight
9%5%246%35%6%6%10%40%
1826
June1st to 15thNight
5%4245%2346%9%50%
1676
16th to endNight
6%3244345%7%11%46%
1560
July1st to 15thNight
9%5%2433435%8%49%
1560
16th to endNight
7%3245%3447%9%47%
1829
August1st to 15thNight
5%4245%3446%10%49%
1726
16th to endNight
5%22342446%10%53%
2010
September1st to 15thNight
13%41332445%6%50%
2073
16th to endNight
12%425%423435%51%
2145
October1st to 15thNight
9%41433445%7%51%
2098
16th to endNight
17%6%24423345%43%
2403
November1st to 15thNight
14%5%25%423446%46%
2471
16th to endNight
18%9%34424445%37%
2535
December1st to 15thNight
21%10%5%7%434345%29%
2535
16th to endNight
22%13%47%6%24445%24%
2769

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
20%11%5%8%6%33435%27%
1565
16th to endDay
14%12%5%8%7%34445%29%
1872
February1st to 15thDay
17%11%5%8%425%335%31%
1855
16th to endDay
17%13%5%8%5%2435%429%
1710
March1st to 15thDay
22%8%36%42335%5%33%
2015
16th to endDay
20%11%35%5%34445%31%
2287
April1st to 15thDay
17%7%35%434446%37%
2318
16th to endDay
17%6%25%5%3335%7%38%
2459
May1st to 15thDay
21%6%246%3445%6%32%
2526
16th to endDay
11%6%36%6%36%5%5%8%34%
2639
June1st to 15thDay
11%425%5%346%6%8%42%
2610
16th to endDay
9%425%6%36%6%5%9%40%
2730
July1st to 15thDay
11%5%25%6%45%5%6%8%38%
2730
16th to endDay
9%425%5%47%6%6%10%38%
2689
August1st to 15thDay
7%426%6%35%5%6%9%41%
2487
16th to endDay
7%425%436%5%6%9%42%
2542
September1st to 15thDay
14%5%25%4345%47%43%
2204
16th to endDay
14%5%25%423346%46%
2145
October1st to 15thDay
11%426%5%3445%6%45%
2032
16th to endDay
17%6%25%423346%42%
1818
November1st to 15thDay
11%6%46%424336%47%
1717
16th to endDay
16%10%36%423346%38%
1755
December1st to 15thDay
22%11%5%6%6%3334427%
1755
16th to endDay
21%13%46%6%33335%26%
1800
January1st to 15thNight
19%11%410%6%3443426%
2697
16th to endNight
16%13%5%7%5%2434430%
2704
February1st to 15thNight
19%11%38%5%23346%30%
2325
16th to endNight
18%12%47%5%2345%7%27%
2049
March1st to 15thNight
17%10%36%5%3335%6%34%
2275
16th to endNight
18%8%25%5%245%47%35%
2288
April1st to 15thNight
16%7%45%424446%39%
1970
16th to endNight
14%7%25%5%3445%7%40%
1774
May1st to 15thNight
18%6%35%5%2445%8%35%
1754
16th to endNight
9%5%25%5%35%6%5%11%39%
1826
June1st to 15thNight
6%4245%2346%11%49%
1676
16th to endNight
5%3234346%6%11%46%
1560
July1st to 15thNight
9%42443435%9%48%
1560
16th to endNight
6%3244435%6%10%47%
1829
August1st to 15thNight
5%425%42446%10%48%
1726
16th to endNight
5%31442346%10%53%
2010
September1st to 15thNight
12%41332345%7%49%
2073
16th to endNight
12%5%24423345%51%
2145
October1st to 15thNight
9%42442445%7%50%
2098
16th to endNight
17%6%25%423445%43%
2403
November1st to 15thNight
13%5%25%423446%46%
2471
16th to endNight
18%9%24424346%37%
2535
December1st to 15thNight
21%10%5%7%5%24445%28%
2535
16th to endNight
22%13%47%5%24335%24%
2769

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
59%37%16%12%
1566
16th to endDay
56%211%22%6%
1872
February1st to 15thDay
55%310%20%9%
1857
16th to endDay
56%210%21%8%
1710
March1st to 15thDay
53%211%20%10%1
2015
16th to endDay
54%310%20%9%1
2288
April1st to 15thDay
47%310%23%14%1
2318
16th to endDay
45%29%23%14%4
2459
May1st to 15thDay
50%413%18%11%1
2526
16th to endDay
45%5%13%20%13%1
2643
June1st to 15thDay
37%413%25%17%2
2610
16th to endDay
39%5%11%23%16%3
2730
July1st to 15thDay
42%411%19%18%3
2581
16th to endDay
38%5%13%25%14%2
2533
August1st to 15thDay
37%412%25%17%2
2474
16th to endDay
35%413%24%16%4
2542
September1st to 15thDay
40%410%20%18%5%
2204
16th to endDay
39%37%24%23%1
2145
October1st to 15thDay
38%37%26%19%3
2032
16th to endDay
43%29%27%15%1
1818
November1st to 15thDay
38%36%26%19%5%
1717
16th to endDay
46%27%25%15%
1755
December1st to 15thDay
60%28%18%9%
1755
16th to endDay
61%29%17%8%
1800
January1st to 15thNight
61%35%17%11%
2697
16th to endNight
57%29%21%7%
2704
February1st to 15thNight
56%111%21%8%1
2334
16th to endNight
55%311%20%8%
2049
March1st to 15thNight
50%38%22%13%1
2275
16th to endNight
48%312%23%10%1
2288
April1st to 15thNight
45%28%24%16%2
1970
16th to endNight
43%310%20%15%7%
1774
May1st to 15thNight
46%413%23%10%2
1755
16th to endNight
37%5%16%21%15%3
1828
June1st to 15thNight
28%413%29%19%3
1676
16th to endNight
29%5%17%22%20%4
1560
July1st to 15thNight
34%412%24%18%6%
1480
16th to endNight
30%5%13%29%18%2
1722
August1st to 15thNight
30%5%14%27%18%3
1715
16th to endNight
26%415%29%19%4
2010
September1st to 15thNight
32%411%25%20%5%
2073
16th to endNight
35%26%25%26%3
2145
October1st to 15thNight
31%39%30%21%4
2098
16th to endNight
42%37%26%18%2
2403
November1st to 15thNight
38%38%22%22%4
2471
16th to endNight
48%29%22%15%1
2535
December1st to 15thNight
58%29%18%10%
2535
16th to endNight
62%210%16%7%
2769

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
28%8%36%16%8%
135
16th to endDay
22%13%39%21%2
144
February1st to 15thDay
28%14%39%14%3
135
16th to endDay
29%10%40%12%6%
120
March1st to 15thDay
23%12%39%21%2
200
16th to endDay
26%9%32%21%9%1
352
April1st to 15thDay
22%13%25%24%13%2
330
16th to endDay
19%7%24%27%13%8%
319
May1st to 15thDay
21%6%24%27%11%7%
348
16th to endDay
19%317%24%21%14%
395
June1st to 15thDay
10%214%33%25%13%
450
16th to endDay
11%320%31%21%11%
570
July1st to 15thDay
14%314%26%25%16%
550
16th to endDay
11%7%27%27%24%
405
August1st to 15thDay
11%16%22%30%26%
358
16th to endDay
9%110%23%35%19%
396
September1st to 15thDay
15%211%19%31%19%
375
16th to endDay
20%113%17%29%17%
374
October1st to 15thDay
13%318%33%22%10%
345
16th to endDay
16%432%26%19%2
234
November1st to 15thDay
16%7%27%24%15%8%
135
16th to endDay
20%7%34%28%8%
135
December1st to 15thDay
16%15%39%17%9%1
135
16th to endDay
30%13%41%12%1
144
January1st to 15thNight
24%10%33%24%5%
956
16th to endNight
25%11%34%25%3
832
February1st to 15thNight
26%11%31%28%1
764
16th to endNight
26%10%33%26%2
683
March1st to 15thNight
25%9%29%29%5%
780
16th to endNight
22%7%29%29%10%
832
April1st to 15thNight
21%7%29%30%10%
607
16th to endNight
17%5%27%35%12%2
579
May1st to 15thNight
20%325%32%16%1
585
16th to endNight
12%116%35%26%6%
611
June1st to 15thNight
8%115%41%29%3
585
16th to endNight
7%114%41%31%3
585
July1st to 15thNight
11%110%36%34%5%
555
16th to endNight
10%6%31%42%7%
612
August1st to 15thNight
8%6%36%40%6%
575
16th to endNight
6%15%34%43%7%
621
September1st to 15thNight
15%29%26%38%7%
708
16th to endNight
15%213%28%34%5%
777
October1st to 15thNight
12%319%33%26%5%
752
16th to endNight
20%5%25%31%14%1
768
November1st to 15thNight
18%6%23%29%19%1
760
16th to endNight
25%8%26%27%11%
780
December1st to 15thNight
27%9%28%24%9%1
780
16th to endNight
29%9%31%24%4
897
Page generated at 2018-10-09 10:39:09. Version ac04

Copyright 2018 A. Danko


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