Holmdel
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Holmdel 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
37%
15669
19%
48795
11%
15638
47%
15638
24%
31167

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%
780
20%
2716
9%
776
39%
776
21%
1681
January16th to endNight
20%
832
21%
2793
7%
832
39%
832
21%
1738
February1st to 15thNight
18%
760
18%
2397
4%
757
34%
757
20%
1548
February16th to endNight
21%
631
26%
1893
8%
631
43%
631
24%
1174
March1st to 15thNight
23%
720
20%
2148
9%
720
37%
720
24%
1398
March16th to endNight
27%
768
22%
1996
8%
768
38%
768
27%
1342
April1st to 15thNight
31%
718
17%
1796
6%
718
37%
718
28%
1235
April16th to endNight
37%
717
18%
1797
7%
717
42%
717
28%
1231
May1st to 15thNight
33%
510
17%
1590
9%
510
40%
510
21%
1088
May16th to endNight
50%
374
15%
1497
15%
374
55%
374
18%
958
June1st to 15thNight
49%
360
14%
1440
14%
360
56%
360
18%
923
June16th to endNight
64%
360
14%
1440
17%
360
68%
360
25%
825
July1st to 15thNight
60%
340
13%
1360
16%
340
62%
340
20%
822
July16th to endNight
66%
376
16%
1418
17%
354
72%
354
24%
832
August1st to 15thNight
64%
582
18%
1653
13%
580
65%
580
32%
1035
August16th to endNight
65%
764
18%
1910
11%
764
66%
764
32%
1266
September1st to 15thNight
54%
720
23%
1800
13%
720
57%
720
33%
1191
September16th to endNight
55%
717
24%
1968
19%
717
59%
717
32%
1253
October1st to 15thNight
43%
720
20%
2107
15%
720
50%
720
27%
1342
October16th to endNight
34%
768
24%
2388
14%
768
48%
768
27%
1460
November1st to 15thNight
34%
760
22%
2472
12%
760
48%
760
25%
1527
November16th to endNight
30%
780
21%
2574
11%
780
43%
780
22%
1633
December1st to 15thNight
25%
780
16%
2730
7%
780
37%
780
17%
1810
December16th to endNight
19%
832
21%
2912
6%
832
37%
832
20%
1855

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%6%24424446%43%
48965
Cloud CoverDay
15%5%25%42445%7%41%
49292
Night
15%6%2442445%6%43%
48971
TransparencyDay
41%6%12%21%15%2
48971
Night
40%5%12%22%16%2
48795
SeeingDay
19%5%25%28%16%4
6242
Night
18%7%30%29%11%1
15670

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%6%34434435%44%
1552
16th to endDay
16%7%34323446%43%
1781
February1st to 15thDay
16%7%35%5%24345%41%
1764
16th to endDay
14%6%36%5%345%46%40%
1580
March1st to 15thDay
17%6%26%425%347%38%
1801
16th to endDay
17%6%25%423335%44%
2227
April1st to 15thDay
18%6%3432335%7%41%
2152
16th to endDay
15%5%2443446%6%42%
2160
May1st to 15thDay
19%6%245%3445%7%35%
2370
16th to endDay
18%5%244245%5%8%37%
2618
June1st to 15thDay
17%5%25%4245%5%10%36%
2520
16th to endDay
10%425%6%45%5%6%9%39%
2520
July1st to 15thDay
10%5%25%5%36%6%7%9%37%
2520
16th to endDay
10%5%25%6%36%6%7%9%36%
2654
August1st to 15thDay
10%5%25%6%335%7%9%41%
2283
16th to endDay
13%5%1442445%9%42%
2292
September1st to 15thDay
13%5%24423446%47%
2160
16th to endDay
14%426%5%2445%6%42%
1990
October1st to 15thDay
18%6%23414446%43%
1851
16th to endDay
17%423214436%47%
1835
November1st to 15thDay
18%6%25%42333445%
1716
16th to endDay
15%423423446%47%
1713
December1st to 15thDay
15%6%35%324446%42%
1560
16th to endDay
19%7%3443345%5%39%
1664
January1st to 15thNight
17%6%14423436%44%
2716
16th to endNight
17%7%24323446%43%
2793
February1st to 15thNight
15%8%35%423445%41%
2396
16th to endNight
15%6%23324446%46%
1893
March1st to 15thNight
18%5%24423248%43%
2135
16th to endNight
17%7%3442334444%
1996
April1st to 15thNight
16%7%2442445%6%41%
1796
16th to endNight
17%5%3443435%7%41%
1797
May1st to 15thNight
17%8%35%5%23447%37%
1590
16th to endNight
17%5%244245%6%7%39%
1495
June1st to 15thNight
18%5%24425%45%7%38%
1440
16th to endNight
8%4146%35%6%6%9%43%
1440
July1st to 15thNight
8%426%5%35%6%6%11%39%
1440
16th to endNight
7%5%25%336%7%7%9%42%
1514
August1st to 15thNight
9%414425%5%5%9%46%
1663
16th to endNight
11%424435%46%8%43%
1910
September1st to 15thNight
13%4235%3445%7%46%
1800
16th to endNight
13%5%25%423346%47%
1968
October1st to 15thNight
16%425%33345%6%44%
2107
16th to endNight
17%5%24313335%49%
2388
November1st to 15thNight
16%5%24423335%47%
2472
16th to endNight
16%5%25%434446%42%
2574
December1st to 15thNight
19%7%25%5%34446%36%
2730
16th to endNight
17%7%24324447%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
14%6%34434436%43%
1552
16th to endDay
16%7%24324446%43%
1781
February1st to 15thDay
16%6%35%5%24335%41%
1764
16th to endDay
13%6%36%5%345%46%40%
1580
March1st to 15thDay
17%6%35%5%15%447%38%
1811
16th to endDay
17%7%25%42333444%
2226
April1st to 15thDay
18%7%24323347%41%
2152
16th to endDay
15%5%1443446%7%42%
2160
May1st to 15thDay
18%7%245%25%46%6%35%
2370
16th to endDay
18%5%2442446%8%37%
2618
June1st to 15thDay
17%5%24425%5%6%9%36%
2520
16th to endDay
9%425%5%45%5%6%9%39%
2520
July1st to 15thDay
10%5%25%5%35%6%7%9%37%
2520
16th to endDay
9%5%35%5%46%6%7%9%36%
2654
August1st to 15thDay
10%5%25%6%245%6%9%41%
2283
16th to endDay
13%5%2443445%9%41%
2292
September1st to 15thDay
13%5%14333446%47%
2160
16th to endDay
15%436%5%2445%5%42%
1990
October1st to 15thDay
18%6%23314436%44%
1851
16th to endDay
17%423214446%47%
1835
November1st to 15thDay
18%6%25%413335%44%
1716
16th to endDay
15%433423346%46%
1713
December1st to 15thDay
15%6%35%324446%42%
1560
16th to endDay
19%7%2443445%5%38%
1664
January1st to 15thNight
17%6%24423435%44%
2716
16th to endNight
17%7%23323446%43%
2793
February1st to 15thNight
15%8%36%42245%5%41%
2389
16th to endNight
15%6%23324446%46%
1893
March1st to 15thNight
18%6%24423247%43%
2148
16th to endNight
17%6%3441334444%
1996
April1st to 15thNight
16%7%25%43435%5%41%
1796
16th to endNight
17%5%25%43435%7%41%
1797
May1st to 15thNight
17%7%35%424347%37%
1590
16th to endNight
16%5%35%4245%6%6%39%
1495
June1st to 15thNight
18%5%24425%45%7%39%
1440
16th to endNight
8%3246%35%6%5%9%43%
1440
July1st to 15thNight
8%5%26%5%35%5%6%11%38%
1440
16th to endNight
7%435%336%6%7%9%42%
1514
August1st to 15thNight
9%4244345%6%9%46%
1663
16th to endNight
11%425%425%46%7%43%
1910
September1st to 15thNight
13%42443445%7%45%
1800
16th to endNight
13%5%25%423347%47%
1968
October1st to 15thNight
16%425%32345%6%44%
2107
16th to endNight
17%5%24323345%49%
2388
November1st to 15thNight
16%5%24423335%47%
2472
16th to endNight
15%5%25%5%24446%42%
2574
December1st to 15thNight
19%7%25%43445%6%36%
2730
16th to endNight
17%7%24324447%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
41%6%12%22%12%4
1553
16th to endDay
41%413%23%14%2
1781
February1st to 15thDay
44%5%11%22%13%2
1767
16th to endDay
43%411%25%12%1
1580
March1st to 15thDay
44%5%14%21%11%2
1811
16th to endDay
44%39%21%16%3
2227
April1st to 15thDay
42%410%23%14%4
2152
16th to endDay
39%6%12%17%21%2
2160
May1st to 15thDay
46%7%10%18%15%1
2370
16th to endDay
43%7%14%19%13%1
2622
June1st to 15thDay
42%8%15%21%11%
2520
16th to endDay
38%10%13%22%13%1
2520
July1st to 15thDay
39%8%13%19%16%2
2371
16th to endDay
40%8%14%23%11%2
2487
August1st to 15thDay
36%7%14%22%16%1
2269
16th to endDay
36%7%13%21%18%2
2292
September1st to 15thDay
36%6%12%21%21%1
2160
16th to endDay
41%5%10%18%22%1
1990
October1st to 15thDay
41%6%12%19%18%1
1851
16th to endDay
37%411%25%18%2
1835
November1st to 15thDay
42%412%21%17%1
1716
16th to endDay
39%312%24%17%2
1713
December1st to 15thDay
41%6%15%20%13%1
1560
16th to endDay
46%5%14%19%13%1
1664
January1st to 15thNight
41%5%12%22%15%3
2716
16th to endNight
41%411%25%15%1
2793
February1st to 15thNight
43%413%21%14%2
2397
16th to endNight
37%5%9%25%18%3
1893
March1st to 15thNight
42%412%22%14%3
2148
16th to endNight
42%410%20%17%5%
1996
April1st to 15thNight
42%5%11%19%17%3
1796
16th to endNight
42%6%9%16%22%3
1797
May1st to 15thNight
46%6%10%16%17%2
1590
16th to endNight
43%8%13%17%14%2
1497
June1st to 15thNight
44%7%12%19%15%
1440
16th to endNight
34%8%15%24%15%1
1440
July1st to 15thNight
38%9%15%21%13%2
1360
16th to endNight
33%11%16%25%12%2
1418
August1st to 15thNight
33%8%15%23%17%2
1653
16th to endNight
36%7%12%20%20%1
1910
September1st to 15thNight
36%6%10%23%20%1
1800
16th to endNight
38%48%22%24%2
1968
October1st to 15thNight
39%5%12%22%16%2
2107
16th to endNight
37%410%27%17%1
2388
November1st to 15thNight
40%410%21%18%4
2472
16th to endNight
41%5%10%24%14%2
2574
December1st to 15thNight
46%5%13%20%11%1
2730
16th to endNight
43%5%12%23%13%1
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
17%15%43%14%7%1
90
16th to endDay
28%5%37%24%4
123
February1st to 15thDay
24%15%38%21%1
200
16th to endDay
15%12%41%25%4
239
March1st to 15thDay
18%12%38%24%6%
270
16th to endDay
23%9%38%20%42
288
April1st to 15thDay
21%8%32%24%10%2
270
16th to endDay
22%5%29%27%11%3
270
May1st to 15thDay
28%331%20%12%2
288
16th to endDay
25%218%28%22%3
331
June1st to 15thDay
18%324%28%21%3
315
16th to endDay
13%21%43%17%3
315
July1st to 15thDay
14%117%33%26%6%
305
16th to endDay
12%113%38%27%6%
326
August1st to 15thDay
13%213%33%29%7%
313
16th to endDay
13%8%37%26%12%
332
September1st to 15thDay
14%223%27%20%10%
315
16th to endDay
21%116%28%20%12%
314
October1st to 15thDay
24%317%24%22%7%
315
16th to endDay
14%7%31%27%16%1
314
November1st to 15thDay
23%7%26%26%15%1
280
16th to endDay
15%12%37%20%13%1
243
December1st to 15thDay
20%17%31%17%12%1
90
16th to endDay
29%9%40%18%2
96
January1st to 15thNight
20%13%38%23%3
780
16th to endNight
21%12%40%22%2
832
February1st to 15thNight
19%13%43%21%1
760
16th to endNight
19%15%40%22%1
631
March1st to 15thNight
20%12%38%23%5%
720
16th to endNight
20%8%38%24%7%
768
April1st to 15thNight
19%8%37%29%5%
718
16th to endNight
20%433%33%8%
717
May1st to 15thNight
22%5%31%29%10%
510
16th to endNight
18%320%38%15%2
375
June1st to 15thNight
20%218%38%18%
360
16th to endNight
8%117%49%21%
360
July1st to 15thNight
12%117%45%22%
340
16th to endNight
10%114%44%26%1
376
August1st to 15thNight
10%113%46%25%2
582
16th to endNight
14%110%38%29%4
764
September1st to 15thNight
16%120%37%20%3
720
16th to endNight
16%219%32%22%6%
717
October1st to 15thNight
20%6%24%28%18%2
720
16th to endNight
20%7%32%27%10%
768
November1st to 15thNight
18%8%32%24%13%1
760
16th to endNight
17%12%34%25%9%
780
December1st to 15thNight
23%12%33%22%7%1
780
16th to endNight
21%10%45%20%2
832
Page generated at 2018-02-15 10:58:45. Version ac04

Copyright 2018 A. Danko


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