Ocean City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ocean City 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
44%
15879
20%
48803
13%
15843
52%
15843
25%
30888

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
29%
778
22%
2703
9%
776
45%
776
21%
1612
January16th to endNight
25%
832
22%
2704
9%
832
40%
832
22%
1681
February1st to 15thNight
25%
759
19%
2398
9%
757
38%
757
23%
1505
February16th to endNight
28%
631
27%
1893
12%
631
47%
631
25%
1168
March1st to 15thNight
32%
720
20%
2097
11%
720
44%
720
25%
1346
March16th to endNight
35%
768
21%
2025
11%
768
44%
768
27%
1361
April1st to 15thNight
39%
718
19%
1796
7%
718
45%
718
31%
1204
April16th to endNight
49%
720
17%
1800
8%
720
52%
720
31%
1223
May1st to 15thNight
43%
603
17%
1683
9%
603
48%
603
26%
1140
May16th to endNight
58%
375
15%
1497
17%
374
62%
374
22%
902
June1st to 15thNight
60%
360
16%
1440
19%
360
63%
360
21%
862
June16th to endNight
63%
360
13%
1440
16%
360
64%
360
20%
882
July1st to 15thNight
66%
340
13%
1360
18%
340
67%
340
22%
817
July16th to endNight
70%
451
15%
1487
16%
423
73%
423
28%
876
August1st to 15thNight
68%
623
16%
1693
12%
620
68%
620
29%
1121
August16th to endNight
68%
764
19%
1910
13%
764
69%
764
35%
1251
September1st to 15thNight
63%
720
24%
1800
17%
720
65%
720
34%
1185
September16th to endNight
53%
717
20%
1947
17%
717
56%
717
26%
1336
October1st to 15thNight
50%
720
23%
2140
21%
720
56%
720
28%
1368
October16th to endNight
43%
768
29%
2325
21%
768
55%
768
30%
1398
November1st to 15thNight
40%
760
19%
2472
13%
760
50%
760
24%
1556
November16th to endNight
39%
780
24%
2551
16%
780
51%
780
24%
1552
December1st to 15thNight
29%
780
18%
2730
10%
780
40%
780
19%
1735
December16th to endNight
27%
832
22%
2912
10%
832
44%
832
21%
1807

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
13%5%2443445%8%43%
49269
Night
14%6%2442445%7%42%
48980
Cloud CoverDay
13%5%2442445%8%43%
49278
Night
14%6%2442445%7%42%
48986
TransparencyDay
38%5%13%25%15%2
48964
Night
41%411%23%16%2
48803
SeeingDay
17%417%29%24%6%
6303
Night
17%6%23%30%18%3
15882

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%5%25%4235%5%7%43%
1562
16th to endDay
16%6%245%2335%6%43%
1872
February1st to 15thDay
15%7%35%43445%6%40%
1763
16th to endDay
14%7%244345%47%42%
1580
March1st to 15thDay
16%5%23424346%46%
1850
16th to endDay
16%5%25%424447%43%
2199
April1st to 15thDay
14%424324447%47%
2152
16th to endDay
14%5%24434448%44%
2160
May1st to 15thDay
14%5%25%424348%42%
2277
16th to endDay
12%42443445%9%43%
2618
June1st to 15thDay
12%4144345%6%10%41%
2520
16th to endDay
7%4244346%6%10%44%
2520
July1st to 15thDay
9%415%4345%6%11%44%
2520
16th to endDay
6%315%5%37%7%8%11%38%
2577
August1st to 15thDay
9%6%25%5%35%6%7%10%39%
2242
16th to endDay
9%324435%5%7%9%44%
2292
September1st to 15thDay
12%4145%25%46%8%44%
2160
16th to endDay
16%7%245%24447%40%
2013
October1st to 15thDay
16%6%15%42345%6%42%
1818
16th to endDay
13%5%23434336%49%
1899
November1st to 15thDay
17%7%25%424447%39%
1716
16th to endDay
12%425%334347%48%
1735
December1st to 15thDay
13%5%35%435%45%7%40%
1560
16th to endDay
19%6%35%433346%40%
1664
January1st to 15thNight
15%5%2342345%7%44%
2703
16th to endNight
16%7%2442445%6%42%
2704
February1st to 15thNight
16%7%24414345%44%
2397
16th to endNight
13%6%24324446%47%
1893
March1st to 15thNight
16%5%25%423447%43%
2084
16th to endNight
18%7%25%323245%41%
2025
April1st to 15thNight
14%7%24424345%44%
1796
16th to endNight
16%6%2442435%6%41%
1800
May1st to 15thNight
16%8%35%5%2435%8%37%
1683
16th to endNight
12%7%3343445%8%40%
1495
June1st to 15thNight
13%5%34415%35%8%41%
1440
16th to endNight
7%5%35%7%46%7%6%9%37%
1440
July1st to 15thNight
6%5%26%6%35%6%7%10%37%
1440
16th to endNight
6%425%5%45%6%7%9%39%
1589
August1st to 15thNight
7%5%16%5%35%5%7%9%40%
1704
16th to endNight
9%5%25%435%5%5%7%44%
1910
September1st to 15thNight
13%5%2442445%9%43%
1800
16th to endNight
16%6%25%43346%6%39%
1947
October1st to 15thNight
17%5%25%42445%6%43%
2140
16th to endNight
15%5%14323345%49%
2325
November1st to 15thNight
17%5%33424335%45%
2472
16th to endNight
13%6%25%42335%6%45%
2551
December1st to 15thNight
16%6%36%425%45%6%38%
2730
16th to endNight
16%6%24424447%43%
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%5%25%42245%8%42%
1562
16th to endDay
15%7%25%5%23446%43%
1872
February1st to 15thDay
15%8%25%4245%46%40%
1763
16th to endDay
14%7%2442445%7%42%
1580
March1st to 15thDay
16%433423347%45%
1860
16th to endDay
16%6%34423447%42%
2198
April1st to 15thDay
15%423424447%47%
2152
16th to endDay
14%5%24424447%45%
2160
May1st to 15thDay
13%6%35%5%3345%7%41%
2277
16th to endDay
12%42442445%9%45%
2618
June1st to 15thDay
13%323425%6%6%10%42%
2520
16th to endDay
7%325%435%5%6%10%45%
2520
July1st to 15thDay
8%4244345%6%10%44%
2520
16th to endDay
6%2145%37%6%8%12%39%
2577
August1st to 15thDay
9%5%245%35%5%7%9%41%
2242
16th to endDay
9%414435%5%6%9%45%
2292
September1st to 15thDay
11%5%244345%6%8%45%
2160
16th to endDay
17%6%35%5%34347%38%
2013
October1st to 15thDay
16%5%2442346%7%43%
1818
16th to endDay
14%414424436%49%
1899
November1st to 15thDay
18%6%34425%446%39%
1716
16th to endDay
13%424424346%49%
1735
December1st to 15thDay
14%5%36%5%2445%7%40%
1560
16th to endDay
19%6%35%5%22347%39%
1664
January1st to 15thNight
15%5%24324448%44%
2703
16th to endNight
16%7%24324446%43%
2704
February1st to 15thNight
16%7%25%423345%44%
2390
16th to endNight
13%6%24324346%47%
1893
March1st to 15thNight
17%6%25%414346%43%
2097
16th to endNight
18%6%35%423335%42%
2025
April1st to 15thNight
15%6%24423445%44%
1796
16th to endNight
16%6%24425%45%7%41%
1800
May1st to 15thNight
16%6%36%5%2445%7%37%
1683
16th to endNight
11%6%25%4345%48%41%
1495
June1st to 15thNight
13%435%42445%9%41%
1440
16th to endNight
7%5%35%6%5%6%6%6%9%37%
1440
July1st to 15thNight
6%5%25%6%45%6%8%10%37%
1440
16th to endNight
6%435%6%36%5%7%10%39%
1589
August1st to 15thNight
7%426%6%36%5%7%8%40%
1704
16th to endNight
9%425%5%345%6%7%44%
1910
September1st to 15thNight
13%42432445%8%43%
1800
16th to endNight
16%6%25%5%235%47%39%
1947
October1st to 15thNight
17%5%24423347%42%
2140
16th to endNight
14%6%23324336%49%
2325
November1st to 15thNight
18%5%24324345%45%
2472
16th to endNight
14%6%24423446%45%
2551
December1st to 15thNight
17%5%35%42445%6%38%
2730
16th to endNight
17%5%34424346%43%
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%413%22%15%3
1563
16th to endDay
42%311%24%16%2
1872
February1st to 15thDay
44%211%24%13%3
1766
16th to endDay
40%312%26%15%2
1580
March1st to 15thDay
39%314%23%16%2
1860
16th to endDay
40%5%10%24%16%2
2199
April1st to 15thDay
36%410%26%17%4
2152
16th to endDay
38%411%19%19%5%
2160
May1st to 15thDay
41%414%23%13%2
2277
16th to endDay
36%417%26%12%1
2622
June1st to 15thDay
35%6%16%28%12%
2520
16th to endDay
32%6%18%25%14%2
2520
July1st to 15thDay
32%8%17%26%12%1
2371
16th to endDay
30%9%17%27%13%1
2416
August1st to 15thDay
35%7%15%26%14%
2229
16th to endDay
33%7%16%24%16%2
2292
September1st to 15thDay
35%5%13%23%18%2
2160
16th to endDay
45%47%20%19%1
2013
October1st to 15thDay
38%411%27%14%3
1818
16th to endDay
36%37%28%21%2
1899
November1st to 15thDay
46%39%23%14%3
1716
16th to endDay
36%410%27%16%4
1735
December1st to 15thDay
43%413%23%12%2
1560
16th to endDay
45%411%25%11%1
1664
January1st to 15thNight
39%411%24%17%2
2703
16th to endNight
42%39%25%15%3
2704
February1st to 15thNight
42%39%26%16%2
2398
16th to endNight
38%38%25%20%1
1893
March1st to 15thNight
41%410%25%14%3
2097
16th to endNight
44%29%21%18%3
2025
April1st to 15thNight
41%310%22%17%4
1796
16th to endNight
41%410%18%20%5%
1800
May1st to 15thNight
45%313%20%15%2
1683
16th to endNight
41%5%17%21%13%1
1497
June1st to 15thNight
39%7%12%24%15%1
1440
16th to endNight
40%7%13%19%16%1
1440
July1st to 15thNight
38%7%18%21%12%1
1360
16th to endNight
34%7%17%25%14%
1487
August1st to 15thNight
38%8%13%21%17%
1693
16th to endNight
36%6%15%23%16%2
1910
September1st to 15thNight
37%5%13%23%15%3
1800
16th to endNight
44%5%7%19%20%2
1947
October1st to 15thNight
42%39%25%16%2
2140
16th to endNight
37%38%26%20%3
2325
November1st to 15thNight
42%410%21%16%4
2472
16th to endNight
40%39%24%18%3
2551
December1st to 15thNight
45%313%22%11%2
2730
16th to endNight
42%312%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
18%10%31%28%10%
92
16th to endDay
22%8%27%31%10%
144
February1st to 15thDay
23%13%33%27%2
199
16th to endDay
18%9%32%30%7%
239
March1st to 15thDay
19%10%25%33%10%
270
16th to endDay
20%7%27%32%9%2
288
April1st to 15thDay
17%7%22%34%15%2
270
16th to endDay
22%413%34%21%3
270
May1st to 15thDay
23%323%30%14%4
288
16th to endDay
17%111%27%30%11%
331
June1st to 15thDay
18%111%29%29%9%
315
16th to endDay
10%110%36%34%6%
315
July1st to 15thDay
10%15%31%42%7%
305
16th to endDay
6%1427%44%15%
326
August1st to 15thDay
11%16%30%39%11%
313
16th to endDay
7%6%26%40%17%
332
September1st to 15thDay
16%111%26%30%14%
315
16th to endDay
26%112%25%26%7%
314
October1st to 15thDay
21%113%31%22%8%
315
16th to endDay
12%8%24%25%22%6%
331
November1st to 15thDay
24%325%23%21%2
280
16th to endDay
15%12%29%21%17%3
265
December1st to 15thDay
18%10%25%27%16%1
90
16th to endDay
30%5%34%25%41
96
January1st to 15thNight
18%15%32%24%8%
780
16th to endNight
20%11%37%27%3
832
February1st to 15thNight
20%11%35%30%1
760
16th to endNight
17%15%33%28%4
631
March1st to 15thNight
20%8%32%29%8%
720
16th to endNight
22%6%27%31%9%3
768
April1st to 15thNight
19%331%34%9%
718
16th to endNight
19%219%39%16%1
720
May1st to 15thNight
19%322%38%13%2
603
16th to endNight
16%211%35%28%6%
375
June1st to 15thNight
15%39%36%30%4
360
16th to endNight
8%39%40%35%3
360
July1st to 15thNight
7%27%37%36%7%
340
16th to endNight
7%15%29%46%9%
451
August1st to 15thNight
9%15%34%42%6%
623
16th to endNight
12%6%29%41%9%
764
September1st to 15thNight
15%19%29%37%7%
720
16th to endNight
18%213%29%28%7%
717
October1st to 15thNight
19%5%15%30%22%6%
720
16th to endNight
19%6%25%27%17%3
768
November1st to 15thNight
21%7%24%26%15%3
760
16th to endNight
17%12%24%31%12%1
780
December1st to 15thNight
20%10%32%22%12%1
780
16th to endNight
19%11%37%27%4
832
Page generated at 2018-02-15 10:58:51. Version ac04

Copyright 2018 A. Danko


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