Coyle Field
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Coyle Field clear sky chart from 2005-11-05 to 2018-02-14.

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%
15723
20%
48800
11%
15692
48%
15692
25%
30862

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
26%
780
21%
2716
10%
776
42%
776
21%
1666
January16th to endNight
23%
832
22%
2767
8%
832
41%
832
22%
1713
February1st to 15thNight
21%
760
18%
2398
6%
757
36%
757
21%
1525
February16th to endNight
22%
631
26%
1893
9%
631
43%
631
24%
1163
March1st to 15thNight
26%
720
20%
2134
10%
720
40%
720
25%
1365
March16th to endNight
28%
768
22%
2004
9%
768
37%
768
27%
1365
April1st to 15thNight
28%
718
18%
1796
6%
718
35%
718
28%
1219
April16th to endNight
37%
720
18%
1800
7%
720
41%
720
30%
1221
May1st to 15thNight
34%
532
17%
1612
9%
532
41%
532
21%
1101
May16th to endNight
48%
374
15%
1497
14%
374
54%
374
18%
951
June1st to 15thNight
51%
360
14%
1440
16%
360
57%
360
18%
915
June16th to endNight
62%
360
16%
1440
19%
360
66%
360
25%
818
July1st to 15thNight
58%
340
12%
1360
16%
340
60%
340
21%
835
July16th to endNight
66%
376
16%
1418
18%
354
71%
354
26%
792
August1st to 15thNight
63%
611
18%
1682
13%
609
65%
609
33%
1052
August16th to endNight
64%
764
18%
1910
10%
764
65%
764
33%
1269
September1st to 15thNight
55%
720
24%
1800
14%
720
58%
720
34%
1179
September16th to endNight
57%
717
25%
1962
21%
717
60%
717
32%
1262
October1st to 15thNight
46%
720
22%
2115
17%
720
53%
720
29%
1316
October16th to endNight
36%
768
28%
2373
16%
768
52%
768
30%
1416
November1st to 15thNight
38%
760
22%
2472
15%
760
50%
760
26%
1516
November16th to endNight
33%
780
22%
2569
13%
780
46%
780
23%
1594
December1st to 15thNight
26%
780
17%
2730
7%
780
39%
780
17%
1778
December16th to endNight
22%
832
21%
2912
7%
832
41%
832
20%
1831

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%5%2442445%7%41%
49283
Night
15%5%2442445%7%43%
48970
Cloud CoverDay
14%6%2443445%7%41%
49292
Night
15%6%24424447%43%
48976
TransparencyDay
40%6%12%22%15%2
48971
Night
40%5%11%22%17%2
48800
SeeingDay
18%6%26%26%16%5%
6259
Night
18%7%28%31%12%1
15724

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
13%5%25%435%446%44%
1552
16th to endDay
17%6%1442335%6%44%
1807
February1st to 15thDay
15%7%25%424446%41%
1764
16th to endDay
13%6%27%5%3345%6%41%
1580
March1st to 15thDay
16%5%24424446%41%
1814
16th to endDay
18%6%24424345%42%
2220
April1st to 15thDay
17%6%24323347%43%
2152
16th to endDay
15%5%244235%5%7%43%
2160
May1st to 15thDay
18%5%33434447%38%
2349
16th to endDay
15%5%3443445%7%40%
2618
June1st to 15thDay
14%6%245%35%45%9%37%
2520
16th to endDay
10%4246%36%5%7%9%39%
2520
July1st to 15thDay
10%6%25%5%46%6%6%8%37%
2520
16th to endDay
10%5%246%37%7%8%9%34%
2654
August1st to 15thDay
11%426%6%345%6%7%40%
2252
16th to endDay
11%4245%345%6%8%42%
2292
September1st to 15thDay
14%5%13334347%46%
2160
16th to endDay
15%6%26%5%24347%41%
1997
October1st to 15thDay
19%5%23413447%43%
1842
16th to endDay
17%424323246%49%
1851
November1st to 15thDay
18%5%24423336%44%
1716
16th to endDay
15%4245%24346%47%
1719
December1st to 15thDay
16%5%3442345%6%43%
1560
16th to endDay
20%6%35%323447%39%
1664
January1st to 15thNight
16%6%2432345%7%43%
2716
16th to endNight
17%6%14323446%43%
2767
February1st to 15thNight
16%7%34423346%41%
2397
16th to endNight
16%425%41435%5%47%
1893
March1st to 15thNight
18%5%14423247%44%
2121
16th to endNight
18%6%35%32332445%
2004
April1st to 15thNight
16%7%25%323336%44%
1796
16th to endNight
16%6%3432445%7%42%
1800
May1st to 15thNight
19%7%25%32435%7%36%
1612
16th to endNight
16%7%345%235%5%7%39%
1495
June1st to 15thNight
16%5%25%435%448%39%
1440
16th to endNight
8%5%246%35%46%10%43%
1440
July1st to 15thNight
9%5%36%6%25%5%6%11%37%
1440
16th to endNight
7%3245%45%5%7%10%42%
1514
August1st to 15thNight
8%5%25%5%3446%8%45%
1692
16th to endNight
11%5%2443446%8%44%
1910
September1st to 15thNight
13%42442345%7%46%
1800
16th to endNight
14%6%2432345%7%46%
1962
October1st to 15thNight
17%5%2432235%6%46%
2115
16th to endNight
16%413323345%50%
2373
November1st to 15thNight
15%5%35%323345%47%
2472
16th to endNight
14%6%25%425%346%42%
2569
December1st to 15thNight
19%5%35%42445%5%37%
2730
16th to endNight
16%6%35%425%35%6%40%
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
13%6%25%425%436%44%
1552
16th to endDay
17%6%14424346%44%
1807
February1st to 15thDay
15%7%25%424446%40%
1764
16th to endDay
13%6%36%5%2445%6%41%
1580
March1st to 15thDay
16%5%34425%446%41%
1824
16th to endDay
17%6%24324345%43%
2219
April1st to 15thDay
17%7%24233346%43%
2152
16th to endDay
15%5%244245%5%7%43%
2160
May1st to 15thDay
18%6%335%2445%7%38%
2349
16th to endDay
15%6%3442445%8%39%
2618
June1st to 15thDay
14%6%245%36%5%5%9%36%
2520
16th to endDay
10%4246%35%6%6%9%39%
2520
July1st to 15thDay
9%6%35%5%45%6%6%8%37%
2520
16th to endDay
9%5%35%5%46%6%8%10%34%
2654
August1st to 15thDay
10%5%26%6%35%5%6%8%40%
2252
16th to endDay
12%4244246%7%8%41%
2292
September1st to 15thDay
13%5%1443435%8%46%
2160
16th to endDay
14%6%26%5%23447%40%
1997
October1st to 15thDay
18%6%24323346%43%
1842
16th to endDay
17%5%24323235%49%
1851
November1st to 15thDay
17%6%245%23347%43%
1716
16th to endDay
15%314424346%47%
1719
December1st to 15thDay
16%6%25%423447%42%
1560
16th to endDay
20%6%25%323447%39%
1664
January1st to 15thNight
17%5%2432345%6%43%
2716
16th to endNight
18%5%24424346%43%
2767
February1st to 15thNight
16%7%34423346%42%
2390
16th to endNight
16%424324445%47%
1893
March1st to 15thNight
17%6%23422337%44%
2134
16th to endNight
18%6%35%32332445%
2004
April1st to 15thNight
16%7%25%323446%43%
1796
16th to endNight
16%6%2442445%7%41%
1800
May1st to 15thNight
19%7%25%425%35%8%36%
1612
16th to endNight
17%7%15%5%245%47%38%
1495
June1st to 15thNight
15%6%26%435%448%39%
1440
16th to endNight
8%425%5%345%5%11%43%
1440
July1st to 15thNight
8%6%26%7%25%5%5%12%37%
1440
16th to endNight
6%335%6%45%47%10%41%
1514
August1st to 15thNight
8%5%26%4345%5%9%45%
1692
16th to endNight
11%4245%3446%7%44%
1910
September1st to 15thNight
12%5%2443345%7%46%
1800
16th to endNight
13%7%24323447%45%
1962
October1st to 15thNight
17%5%1442235%6%46%
2115
16th to endNight
16%5%23323345%50%
2373
November1st to 15thNight
15%6%24423335%47%
2472
16th to endNight
15%5%25%43435%6%42%
2569
December1st to 15thNight
18%5%35%5%3445%5%37%
2730
16th to endNight
16%6%35%42445%6%40%
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
40%6%12%21%14%5%
1553
16th to endDay
40%410%26%15%3
1807
February1st to 15thDay
43%411%23%13%2
1767
16th to endDay
42%5%9%25%13%2
1580
March1st to 15thDay
43%413%22%13%2
1824
16th to endDay
41%5%8%23%16%3
2220
April1st to 15thDay
42%49%23%14%5%
2152
16th to endDay
38%6%12%17%21%3
2160
May1st to 15thDay
44%6%11%20%14%2
2349
16th to endDay
41%7%14%22%11%1
2622
June1st to 15thDay
42%8%12%22%11%1
2520
16th to endDay
37%10%13%21%15%1
2520
July1st to 15thDay
41%7%12%23%13%2
2371
16th to endDay
39%9%13%24%10%2
2487
August1st to 15thDay
38%7%14%21%16%1
2238
16th to endDay
35%7%14%21%18%2
2292
September1st to 15thDay
36%5%12%21%22%2
2160
16th to endDay
42%48%18%22%2
1997
October1st to 15thDay
41%411%22%17%2
1842
16th to endDay
37%38%25%21%2
1851
November1st to 15thDay
42%311%23%16%2
1716
16th to endDay
38%39%27%18%2
1719
December1st to 15thDay
41%5%15%22%13%2
1560
16th to endDay
44%5%14%21%13%1
1664
January1st to 15thNight
40%5%10%21%18%4
2716
16th to endNight
41%410%26%16%1
2767
February1st to 15thNight
43%312%23%14%3
2398
16th to endNight
37%49%24%19%4
1893
March1st to 15thNight
41%411%22%16%3
2134
16th to endNight
44%39%20%17%4
2004
April1st to 15thNight
41%410%21%16%4
1796
16th to endNight
41%5%9%17%22%3
1800
May1st to 15thNight
47%5%9%18%16%2
1612
16th to endNight
45%6%13%18%14%2
1497
June1st to 15thNight
44%6%11%19%17%
1440
16th to endNight
35%6%14%25%16%2
1440
July1st to 15thNight
39%8%15%20%12%2
1360
16th to endNight
33%7%19%25%12%1
1418
August1st to 15thNight
34%7%14%22%19%1
1682
16th to endNight
37%6%12%20%20%2
1910
September1st to 15thNight
36%6%11%22%20%2
1800
16th to endNight
37%5%7%22%23%2
1962
October1st to 15thNight
38%412%23%17%3
2115
16th to endNight
36%38%28%19%2
2373
November1st to 15thNight
39%39%22%18%5%
2472
16th to endNight
42%310%23%17%2
2569
December1st to 15thNight
46%5%12%21%12%1
2730
16th to endNight
42%412%23%13%2
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
16%20%38%13%8%2
90
16th to endDay
26%10%35%23%3
129
February1st to 15thDay
22%19%41%16%1
200
16th to endDay
15%15%44%21%2
239
March1st to 15thDay
16%15%34%25%7%
270
16th to endDay
21%10%37%21%5%3
288
April1st to 15thDay
22%9%34%22%8%2
270
16th to endDay
20%5%30%27%10%5%
270
May1st to 15thDay
28%12%24%19%11%3
288
16th to endDay
21%319%26%22%5%
331
June1st to 15thDay
19%326%26%18%6%
315
16th to endDay
12%225%36%18%5%
315
July1st to 15thDay
16%18%31%25%6%
305
16th to endDay
9%117%34%26%9%
326
August1st to 15thDay
13%117%30%25%10%
313
16th to endDay
10%19%33%28%15%
332
September1st to 15thDay
13%225%23%20%15%
315
16th to endDay
21%217%26%20%12%
314
October1st to 15thDay
24%316%26%22%6%
315
16th to endDay
15%8%29%25%16%3
319
November1st to 15thDay
19%8%27%28%13%2
280
16th to endDay
17%10%34%20%13%2
249
December1st to 15thDay
21%16%32%15%14%
90
16th to endDay
27%10%41%19%1
96
January1st to 15thNight
19%13%35%25%6%
780
16th to endNight
21%11%39%26%2
832
February1st to 15thNight
20%13%40%25%1
760
16th to endNight
19%14%38%25%2
631
March1st to 15thNight
20%10%38%25%5%
720
16th to endNight
21%6%37%24%8%1
768
April1st to 15thNight
20%10%35%27%5%
718
16th to endNight
19%432%34%8%
720
May1st to 15thNight
22%7%30%29%8%
532
16th to endNight
19%219%38%18%1
375
June1st to 15thNight
19%319%38%17%1
360
16th to endNight
8%217%50%21%
360
July1st to 15thNight
12%116%46%22%
340
16th to endNight
9%113%44%28%3
376
August1st to 15thNight
10%112%44%27%2
611
16th to endNight
12%212%38%29%4
764
September1st to 15thNight
15%218%36%24%3
720
16th to endNight
18%114%33%26%4
717
October1st to 15thNight
20%421%30%20%2
720
16th to endNight
18%7%32%28%11%1
768
November1st to 15thNight
17%8%29%29%12%1
760
16th to endNight
17%10%31%29%10%1
780
December1st to 15thNight
23%9%32%23%9%1
780
16th to endNight
20%11%39%25%3
832
Page generated at 2018-02-15 10:58:39. Version ac04

Copyright 2018 A. Danko


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