Coinjock
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Coinjock clear sky chart from 2005-11-05 to

2017-09-12
.

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
48%
15496
20%
46851
14%
15459
55%
15459
27%
29555

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
32%
716
20%
2390
10%
716
45%
716
20%
1536
January16th to endNight
28%
768
22%
2496
11%
768
44%
768
24%
1574
February1st to 15thNight
29%
702
21%
2225
12%
701
43%
701
25%
1386
February16th to endNight
31%
631
27%
1893
14%
631
47%
631
31%
1133
March1st to 15thNight
39%
720
21%
2043
14%
720
48%
720
31%
1280
March16th to endNight
40%
768
20%
2056
12%
768
47%
768
27%
1391
April1st to 15thNight
44%
718
20%
1796
8%
718
50%
718
34%
1163
April16th to endNight
50%
720
20%
1800
9%
720
52%
720
33%
1183
May1st to 15thNight
53%
713
15%
1793
8%
713
55%
713
31%
1196
May16th to endNight
67%
374
18%
1497
21%
374
69%
374
26%
846
June1st to 15thNight
65%
360
15%
1440
18%
360
66%
360
23%
847
June16th to endNight
75%
360
17%
1440
22%
360
76%
360
24%
822
July1st to 15thNight
73%
356
13%
1376
15%
356
74%
356
26%
806
July16th to endNight
74%
564
15%
1595
13%
531
76%
531
30%
1000
August1st to 15thNight
67%
626
14%
1696
10%
623
67%
623
27%
1134
August16th to endNight
66%
764
18%
1910
11%
764
66%
764
30%
1316
September1st to 15thNight
61%
707
22%
1768
16%
707
63%
707
30%
1214
September16th to endNight
55%
657
18%
1778
15%
657
57%
657
23%
1241
October1st to 15thNight
55%
660
26%
1980
24%
660
61%
660
29%
1246
October16th to endNight
47%
704
30%
2112
23%
704
58%
704
32%
1249
November1st to 15thNight
43%
700
20%
2225
15%
700
52%
700
25%
1397
November16th to endNight
44%
720
23%
2340
18%
720
53%
720
26%
1396
December1st to 15thNight
38%
720
19%
2514
11%
720
50%
720
22%
1565
December16th to endNight
34%
768
22%
2688
13%
768
48%
768
23%
1634

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
12%5%244345%5%8%42%
47792
Night
13%5%2442445%7%43%
47036
Cloud CoverDay
12%5%244345%5%8%42%
47802
Night
13%5%2442445%7%43%
47040
TransparencyDay
38%5%14%23%15%2
47495
Night
39%5%12%22%16%3
46851
SeeingDay
15%316%28%27%8%
5880
Night
16%421%32%21%3
15503

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
16%6%25%424447%42%
1546
16th to endDay
15%5%24335%5%5%5%43%
1728
February1st to 15thDay
15%6%35%5%2345%5%42%
1636
16th to endDay
13%5%24434347%45%
1580
March1st to 15thDay
13%423433336%50%
1903
16th to endDay
17%5%23424446%43%
2166
April1st to 15thDay
11%6%25%323346%49%
2152
16th to endDay
10%5%245%35%348%47%
2160
May1st to 15thDay
12%5%35%42445%6%42%
2167
16th to endDay
11%414325%6%6%9%42%
2618
June1st to 15thDay
9%4244245%7%11%42%
2520
16th to endDay
6%325%5%36%6%7%12%39%
2520
July1st to 15thDay
7%4145%46%6%8%10%38%
2501
16th to endDay
7%4145%37%8%8%11%37%
2465
August1st to 15thDay
10%5%25%5%35%6%6%10%36%
2238
16th to endDay
10%5%26%5%36%6%7%9%37%
2292
September1st to 15thDay
12%435%5%346%6%8%39%
2112
16th to endDay
19%8%35%5%345%5%7%31%
1848
October1st to 15thDay
16%6%25%423436%43%
1650
16th to endDay
10%5%245%2335%5%51%
1760
November1st to 15thDay
17%7%2442335%6%43%
1631
16th to endDay
14%424323437%48%
1620
December1st to 15thDay
15%5%24424446%42%
1443
16th to endDay
18%6%2442435%5%41%
1536
January1st to 15thNight
14%6%25%5%25%45%7%40%
2390
16th to endNight
16%6%35%41445%5%42%
2496
February1st to 15thNight
18%6%24323445%44%
2224
16th to endNight
12%5%24334445%49%
1893
March1st to 15thNight
14%5%2442335%6%48%
2031
16th to endNight
17%5%25%5%34445%42%
2056
April1st to 15thNight
10%6%25%425%45%7%45%
1796
16th to endNight
15%6%245%23336%46%
1800
May1st to 15thNight
12%5%245%35%5%6%8%40%
1793
16th to endNight
10%5%3332445%10%45%
1495
June1st to 15thNight
9%425%5%36%5%5%10%41%
1440
16th to endNight
5%325%5%36%6%7%10%42%
1440
July1st to 15thNight
7%325%4447%8%12%38%
1457
16th to endNight
9%414436%7%7%11%40%
1703
August1st to 15thNight
9%6%26%5%35%5%6%9%37%
1707
16th to endNight
11%5%36%5%35%5%5%10%36%
1910
September1st to 15thNight
13%5%25%6%3445%8%39%
1768
16th to endNight
18%7%245%34437%36%
1778
October1st to 15thNight
17%415%324435%46%
1980
16th to endNight
13%414323346%52%
2112
November1st to 15thNight
17%5%24423348%43%
2225
16th to endNight
16%423424446%46%
2340
December1st to 15thNight
13%7%25%5%3445%7%40%
2514
16th to endNight
16%6%2442335%6%43%
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
16%6%24433447%41%
1546
16th to endDay
16%5%23435%45%6%42%
1728
February1st to 15thDay
14%6%26%5%2345%6%42%
1636
16th to endDay
13%5%34434447%46%
1580
March1st to 15thDay
12%424434236%50%
1914
16th to endDay
16%5%25%3235%46%43%
2165
April1st to 15thDay
11%5%24423346%50%
2152
16th to endDay
10%5%24434438%48%
2160
May1st to 15thDay
11%5%25%5%26%45%7%42%
2167
16th to endDay
11%424425%6%6%9%43%
2618
June1st to 15thDay
9%4243245%7%11%43%
2520
16th to endDay
6%425%5%35%7%7%12%39%
2520
July1st to 15thDay
7%4246%36%6%7%11%38%
2501
16th to endDay
7%3245%36%8%7%11%38%
2465
August1st to 15thDay
10%5%26%5%36%6%6%10%36%
2238
16th to endDay
10%425%6%45%5%7%10%36%
2292
September1st to 15thDay
11%5%25%5%35%6%5%7%40%
2112
16th to endDay
19%7%36%5%345%47%31%
1848
October1st to 15thDay
16%5%25%5%23335%44%
1650
16th to endDay
10%5%245%33445%50%
1760
November1st to 15thDay
17%6%2442445%5%43%
1631
16th to endDay
13%43432335%7%48%
1620
December1st to 15thDay
15%5%24425%45%6%42%
1443
16th to endDay
19%5%24425%345%41%
1536
January1st to 15thNight
14%6%25%5%25%45%7%39%
2390
16th to endNight
16%6%25%423445%43%
2496
February1st to 15thNight
17%6%23423347%43%
2217
16th to endNight
12%5%24324446%48%
1893
March1st to 15thNight
14%5%24424346%47%
2043
16th to endNight
16%5%25%5%34445%42%
2056
April1st to 15thNight
11%5%25%5%3435%6%45%
1796
16th to endNight
15%6%25%424246%46%
1800
May1st to 15thNight
11%5%345%345%7%8%40%
1792
16th to endNight
10%6%2332445%10%45%
1495
June1st to 15thNight
10%325%5%35%46%9%42%
1440
16th to endNight
6%5%145%45%6%7%11%42%
1440
July1st to 15thNight
6%3245%35%7%8%12%39%
1457
16th to endNight
8%3245%36%7%7%11%40%
1703
August1st to 15thNight
9%6%35%5%36%47%10%37%
1707
16th to endNight
11%6%35%5%346%5%9%37%
1910
September1st to 15thNight
14%5%25%5%3445%8%40%
1768
16th to endNight
18%6%25%43445%7%35%
1778
October1st to 15thNight
16%5%25%323436%46%
1980
16th to endNight
12%5%23323347%51%
2112
November1st to 15thNight
16%5%2442335%7%44%
2225
16th to endNight
15%424323447%46%
2340
December1st to 15thNight
13%7%24435%5%5%6%40%
2514
16th to endNight
16%6%25%423346%43%
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
41%5%10%19%18%3
1547
16th to endDay
42%49%23%17%3
1728
February1st to 15thDay
42%39%22%17%4
1639
16th to endDay
38%311%25%17%3
1580
March1st to 15thDay
36%312%24%18%4
1914
16th to endDay
40%312%22%17%3
2166
April1st to 15thDay
35%410%26%19%4
2152
16th to endDay
34%415%21%18%5%
2160
May1st to 15thDay
38%6%15%23%13%1
2167
16th to endDay
34%6%17%26%13%1
2622
June1st to 15thDay
32%6%19%27%12%
2520
16th to endDay
34%8%18%24%12%1
2520
July1st to 15thDay
34%8%20%25%10%
2353
16th to endDay
32%8%19%25%13%
2310
August1st to 15thDay
40%7%18%21%11%
2225
16th to endDay
38%6%19%22%9%2
2292
September1st to 15thDay
38%7%15%20%14%2
2112
16th to endDay
49%5%10%18%13%
1848
October1st to 15thDay
41%48%24%19%2
1650
16th to endDay
35%45%26%23%4
1760
November1st to 15thDay
42%311%19%18%4
1631
16th to endDay
35%411%25%18%4
1620
December1st to 15thDay
42%313%22%15%2
1443
16th to endDay
44%310%22%14%3
1536
January1st to 15thNight
43%5%8%20%17%4
2390
16th to endNight
42%39%22%16%4
2496
February1st to 15thNight
42%27%22%20%4
2225
16th to endNight
35%410%26%18%5%
1893
March1st to 15thNight
37%412%24%16%4
2043
16th to endNight
43%48%22%16%3
2056
April1st to 15thNight
38%313%19%20%4
1796
16th to endNight
40%29%22%19%5%
1800
May1st to 15thNight
39%5%17%24%11%1
1793
16th to endNight
34%7%17%25%12%2
1497
June1st to 15thNight
37%7%17%26%10%
1440
16th to endNight
33%9%18%24%12%1
1440
July1st to 15thNight
33%10%23%20%12%1
1376
16th to endNight
33%9%18%25%11%1
1595
August1st to 15thNight
41%7%18%21%11%
1696
16th to endNight
41%7%16%24%9%1
1910
September1st to 15thNight
41%6%15%19%14%2
1768
16th to endNight
47%5%10%17%17%1
1778
October1st to 15thNight
39%49%23%19%3
1980
16th to endNight
33%47%24%24%4
2112
November1st to 15thNight
40%5%9%17%22%4
2225
16th to endNight
37%49%24%18%5%
2340
December1st to 15thNight
42%413%19%16%3
2514
16th to endNight
42%312%21%15%4
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
22%6%34%31%5%
79
16th to endDay
17%7%37%32%5%
96
February1st to 15thDay
21%11%33%28%5%
152
16th to endDay
13%6%36%34%9%
239
March1st to 15thDay
12%7%34%28%14%1
270
16th to endDay
17%5%26%36%9%5%
288
April1st to 15thDay
15%5%26%31%18%2
270
16th to endDay
11%221%32%27%5%
270
May1st to 15thDay
18%320%37%17%3
288
16th to endDay
15%11%24%31%16%
331
June1st to 15thDay
15%17%25%33%15%
315
16th to endDay
10%6%30%43%8%
315
July1st to 15thDay
9%326%44%14%
305
16th to endDay
11%1123%43%18%
326
August1st to 15thDay
15%1226%38%15%
313
16th to endDay
11%422%43%17%
332
September1st to 15thDay
13%110%23%37%14%
299
16th to endDay
29%17%23%32%5%
254
October1st to 15thDay
27%114%27%24%3
255
16th to endDay
9%5%22%29%24%8%
272
November1st to 15thDay
20%5%25%27%15%5%
244
16th to endDay
16%10%23%25%22%2
240
December1st to 15thDay
25%7%22%26%14%3
63
16th to endDay
25%26%34%14%
64
January1st to 15thNight
16%12%31%29%10%
720
16th to endNight
19%8%37%29%4
768
February1st to 15thNight
23%6%34%31%3
704
16th to endNight
14%9%40%29%6%
631
March1st to 15thNight
16%434%32%11%1
720
16th to endNight
19%427%33%13%1
768
April1st to 15thNight
12%331%36%14%
718
16th to endNight
16%320%39%16%2
720
May1st to 15thNight
15%219%40%19%1
713
16th to endNight
13%27%31%35%9%
375
June1st to 15thNight
10%28%36%34%7%
360
16th to endNight
6%15%43%38%4
360
July1st to 15thNight
8%5%31%45%7%
356
16th to endNight
10%1229%43%10%
564
August1st to 15thNight
13%2233%38%9%
626
16th to endNight
14%1327%42%11%
764
September1st to 15thNight
17%25%25%40%8%
707
16th to endNight
23%18%31%31%4
657
October1st to 15thNight
20%214%30%26%5%
660
16th to endNight
15%6%24%29%18%4
704
November1st to 15thNight
19%5%23%33%14%3
700
16th to endNight
17%7%24%30%17%1
720
December1st to 15thNight
17%7%30%29%15%
720
16th to endNight
18%6%33%34%7%
768
Page generated at 2017-09-13 07:39:02. Version ac04

Copyright 2017 A. Danko


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