Chesapeake Beach Veterans Memorial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chesapeake Beach Veterans Memorial Park 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
34%
15239
20%
46834
10%
15199
46%
15199
22%
29429

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
20%
717
22%
2437
8%
716
38%
716
16%
1504
January16th to endNight
17%
768
23%
2496
7%
768
37%
768
17%
1558
February1st to 15thNight
20%
704
20%
2284
6%
701
39%
701
17%
1395
February16th to endNight
18%
631
25%
1893
6%
631
40%
631
20%
1166
March1st to 15thNight
25%
720
21%
2031
9%
720
38%
720
22%
1292
March16th to endNight
25%
768
21%
2070
6%
768
37%
768
22%
1384
April1st to 15thNight
25%
718
19%
1796
5%
718
33%
718
26%
1176
April16th to endNight
35%
720
19%
1800
6%
720
41%
720
25%
1191
May1st to 15thNight
32%
576
17%
1656
8%
576
39%
576
20%
1125
May16th to endNight
44%
374
17%
1497
12%
374
54%
374
19%
868
June1st to 15thNight
47%
360
19%
1440
18%
360
56%
360
21%
843
June16th to endNight
51%
360
15%
1440
13%
360
58%
360
20%
839
July1st to 15thNight
53%
340
12%
1360
14%
340
56%
340
17%
863
July16th to endNight
59%
523
16%
1554
12%
490
66%
490
29%
913
August1st to 15thNight
58%
560
17%
1630
11%
557
60%
557
26%
1039
August16th to endNight
60%
764
18%
1910
11%
764
61%
764
30%
1282
September1st to 15thNight
55%
707
24%
1768
14%
707
59%
707
32%
1156
September16th to endNight
47%
657
20%
1795
12%
657
53%
657
25%
1196
October1st to 15thNight
40%
660
23%
1980
18%
660
49%
660
24%
1266
October16th to endNight
35%
704
28%
2112
14%
704
52%
704
27%
1255
November1st to 15thNight
30%
700
24%
2244
11%
700
46%
700
23%
1347
November16th to endNight
27%
720
22%
2433
10%
720
43%
720
19%
1465
December1st to 15thNight
24%
720
19%
2520
6%
720
40%
720
14%
1614
December16th to endNight
17%
768
22%
2688
7%
768
37%
768
15%
1692

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%42442445%8%43%
47817
Night
14%5%2442445%7%44%
47016
Cloud CoverDay
13%42442445%8%44%
47827
Night
14%5%2442445%7%44%
47020
TransparencyDay
37%7%12%23%15%2
47517
Night
38%6%11%22%17%3
46834
SeeingDay
16%13%21%25%17%5%
5710
Night
15%21%22%24%13%1
15243

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%5%25%324347%43%
1498
16th to endDay
16%5%25%5%24337%43%
1728
February1st to 15thDay
15%6%2443446%6%42%
1578
16th to endDay
14%6%25%425%5%5%5%42%
1580
March1st to 15thDay
15%5%24434345%45%
1915
16th to endDay
17%6%24423346%42%
2154
April1st to 15thDay
13%5%2343445%7%45%
2152
16th to endDay
15%5%24424445%46%
2160
May1st to 15thDay
16%5%144245%5%9%40%
2304
16th to endDay
13%313345%5%6%10%41%
2618
June1st to 15thDay
11%313436%47%11%42%
2520
16th to endDay
8%3144347%8%10%44%
2520
July1st to 15thDay
8%4245%35%5%6%10%42%
2520
16th to endDay
5%224436%6%9%12%40%
2505
August1st to 15thDay
10%435%5%26%5%6%9%40%
2307
16th to endDay
10%424335%47%8%44%
2292
September1st to 15thDay
12%41442345%8%47%
2112
16th to endDay
16%7%2442446%6%39%
1832
October1st to 15thDay
18%313324446%47%
1650
16th to endDay
14%424423346%50%
1760
November1st to 15thDay
16%5%13324446%49%
1612
16th to endDay
15%5%1432435%6%47%
1524
December1st to 15thDay
15%424424447%44%
1440
16th to endDay
19%6%35%324346%40%
1536
January1st to 15thNight
16%5%25%424447%43%
2437
16th to endNight
17%6%24323345%45%
2496
February1st to 15thNight
14%6%24423446%45%
2282
16th to endNight
14%6%34323346%48%
1893
March1st to 15thNight
15%5%1432435%7%45%
2019
16th to endNight
16%6%25%424447%42%
2070
April1st to 15thNight
14%42442445%6%45%
1796
16th to endNight
17%424324446%46%
1800
May1st to 15thNight
16%5%25%5%2446%8%38%
1656
16th to endNight
13%4245%235%5%9%43%
1495
June1st to 15thNight
11%424425%36%10%43%
1440
16th to endNight
8%5%25%5%35%5%6%10%41%
1440
July1st to 15thNight
8%427%6%36%5%6%9%37%
1440
16th to endNight
6%3245%36%6%7%10%44%
1661
August1st to 15thNight
8%425%5%35%5%6%7%43%
1641
16th to endNight
11%5%15%5%25%5%6%8%42%
1910
September1st to 15thNight
12%42442345%8%45%
1768
16th to endNight
16%6%1442446%7%40%
1795
October1st to 15thNight
17%5%24423346%45%
1980
16th to endNight
15%31332335%6%50%
2112
November1st to 15thNight
15%5%23423335%50%
2244
16th to endNight
15%42432346%7%44%
2433
December1st to 15thNight
16%5%25%425%5%5%6%40%
2520
16th to endNight
17%5%25%424346%42%
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%5%25%32435%7%43%
1498
16th to endDay
15%5%25%434347%43%
1728
February1st to 15thDay
15%6%2343446%6%42%
1578
16th to endDay
13%7%144345%5%6%42%
1580
March1st to 15thDay
14%6%2443435%6%44%
1926
16th to endDay
17%6%245%24346%42%
2153
April1st to 15thDay
13%5%23325%35%8%45%
2152
16th to endDay
15%423324446%46%
2160
May1st to 15thDay
16%5%244235%5%9%41%
2304
16th to endDay
12%4134245%6%9%42%
2618
June1st to 15thDay
10%314336%5%7%10%44%
2520
16th to endDay
8%213335%6%7%11%45%
2520
July1st to 15thDay
8%425%435%6%6%10%43%
2520
16th to endDay
5%314436%6%9%12%42%
2505
August1st to 15thDay
10%425%435%5%6%10%40%
2307
16th to endDay
9%415%4245%7%9%45%
2292
September1st to 15thDay
12%32442445%8%47%
2112
16th to endDay
15%7%243245%5%7%40%
1832
October1st to 15thDay
19%312324346%47%
1650
16th to endDay
14%414422346%50%
1760
November1st to 15thDay
16%413214346%48%
1612
16th to endDay
15%5%24324446%47%
1524
December1st to 15thDay
15%4244245%47%45%
1440
16th to endDay
19%6%2432445%6%40%
1536
January1st to 15thNight
16%425%423447%43%
2437
16th to endNight
17%6%24323345%45%
2496
February1st to 15thNight
14%5%25%423446%46%
2275
16th to endNight
14%6%25%323346%47%
1893
March1st to 15thNight
15%5%2442335%7%44%
2031
16th to endNight
16%6%24424447%42%
2070
April1st to 15thNight
14%42432445%7%45%
1796
16th to endNight
18%41332345%6%46%
1800
May1st to 15thNight
15%6%344245%5%8%38%
1655
16th to endNight
13%4145%245%6%9%42%
1495
June1st to 15thNight
11%4245%3446%10%44%
1440
16th to endNight
8%5%25%5%25%5%6%11%40%
1440
July1st to 15thNight
8%6%25%6%37%5%7%9%38%
1440
16th to endNight
6%3245%36%5%7%10%44%
1661
August1st to 15thNight
8%425%5%35%5%6%8%43%
1641
16th to endNight
11%5%26%435%5%6%8%42%
1910
September1st to 15thNight
13%42442346%7%45%
1768
16th to endNight
16%6%145%2446%7%40%
1795
October1st to 15thNight
18%5%24323336%45%
1980
16th to endNight
15%314323346%50%
2112
November1st to 15thNight
15%5%24313245%50%
2244
16th to endNight
14%5%2442445%6%44%
2433
December1st to 15thNight
16%5%25%425%45%7%40%
2520
16th to endNight
17%5%25%424446%42%
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%6%13%21%13%4
1499
16th to endDay
42%411%23%14%3
1728
February1st to 15thDay
41%411%26%14%1
1580
16th to endDay
42%412%23%15%1
1580
March1st to 15thDay
40%5%11%22%16%3
1926
16th to endDay
43%5%10%20%17%3
2154
April1st to 15thDay
36%6%10%24%18%4
2152
16th to endDay
38%6%10%18%19%6%
2160
May1st to 15thDay
39%8%13%21%15%1
2304
16th to endDay
36%9%15%23%13%1
2622
June1st to 15thDay
34%9%14%26%13%1
2520
16th to endDay
31%11%16%21%17%1
2520
July1st to 15thDay
34%10%14%22%14%2
2371
16th to endDay
31%10%17%23%15%1
2349
August1st to 15thDay
38%9%14%22%14%1
2294
16th to endDay
35%9%14%22%15%3
2292
September1st to 15thDay
34%7%14%21%18%3
2112
16th to endDay
42%7%10%20%17%2
1832
October1st to 15thDay
37%5%9%27%16%3
1650
16th to endDay
36%39%27%19%3
1760
November1st to 15thDay
36%411%23%19%4
1612
16th to endDay
38%49%26%18%2
1524
December1st to 15thDay
39%6%14%23%12%3
1440
16th to endDay
44%5%10%24%14%1
1536
January1st to 15thNight
41%410%21%18%3
2437
16th to endNight
41%410%25%17%1
2496
February1st to 15thNight
39%410%25%17%3
2284
16th to endNight
37%49%25%19%2
1893
March1st to 15thNight
39%411%26%15%2
2031
16th to endNight
42%5%11%20%17%3
2070
April1st to 15thNight
38%410%21%21%3
1796
16th to endNight
38%5%11%19%18%6%
1800
May1st to 15thNight
42%8%12%20%13%2
1656
16th to endNight
35%7%18%20%15%1
1497
June1st to 15thNight
35%8%12%25%16%1
1440
16th to endNight
36%7%15%19%17%2
1440
July1st to 15thNight
40%11%15%17%12%2
1360
16th to endNight
31%8%16%26%15%
1554
August1st to 15thNight
36%8%14%21%18%
1630
16th to endNight
37%7%13%22%16%2
1910
September1st to 15thNight
34%7%11%22%18%4
1768
16th to endNight
39%7%10%18%19%4
1795
October1st to 15thNight
40%49%23%17%3
1980
16th to endNight
34%48%26%22%3
2112
November1st to 15thNight
38%38%22%19%7%
2244
16th to endNight
37%5%10%23%17%4
2433
December1st to 15thNight
43%6%10%22%14%2
2520
16th to endNight
42%5%11%23%13%2
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
23%12%42%19%1
71
16th to endDay
18%20%38%20%1
96
February1st to 15thDay
25%17%36%18%2
93
16th to endDay
16%21%35%23%1
239
March1st to 15thDay
18%22%26%25%5%
270
16th to endDay
19%18%31%22%42
288
April1st to 15thDay
16%18%28%25%10%
270
16th to endDay
20%15%21%26%12%2
270
May1st to 15thDay
25%16%29%15%10%2
288
16th to endDay
19%11%15%25%22%5%
331
June1st to 15thDay
13%12%18%25%21%9%
315
16th to endDay
10%11%20%37%18%2
315
July1st to 15thDay
10%7%10%36%30%4
305
16th to endDay
5%10%9%30%33%10%
326
August1st to 15thDay
16%6%11%26%32%6%
313
16th to endDay
9%5%8%31%32%13%
332
September1st to 15thDay
11%8%19%25%21%14%
299
16th to endDay
27%7%16%19%20%8%
254
October1st to 15thDay
20%11%20%21%21%4
255
16th to endDay
13%14%27%27%13%2
272
November1st to 15thDay
18%17%25%20%12%5%
240
16th to endDay
15%26%24%20%11%2
144
December1st to 15thDay
15%15%35%23%10%1
60
16th to endDay
34%6%37%17%31
64
January1st to 15thNight
16%29%28%20%5%
720
16th to endNight
19%28%32%19%1
768
February1st to 15thNight
15%29%30%21%2
704
16th to endNight
14%30%32%19%2
631
March1st to 15thNight
17%26%28%22%5%
720
16th to endNight
17%23%30%20%5%2
768
April1st to 15thNight
15%24%30%23%5%
718
16th to endNight
17%21%20%26%12%1
720
May1st to 15thNight
17%23%23%23%11%1
576
16th to endNight
12%19%16%25%24%1
375
June1st to 15thNight
11%17%15%31%21%2
360
16th to endNight
6%19%15%37%20%
360
July1st to 15thNight
11%12%12%32%28%1
340
16th to endNight
6%16%9%32%27%5%
523
August1st to 15thNight
10%10%11%39%26%2
560
16th to endNight
13%9%9%31%30%5%
764
September1st to 15thNight
12%10%14%28%29%4
707
16th to endNight
18%11%14%27%23%3
657
October1st to 15thNight
18%15%18%25%19%2
660
16th to endNight
15%20%26%23%13%1
704
November1st to 15thNight
15%24%25%19%13%2
700
16th to endNight
14%30%24%22%7%
720
December1st to 15thNight
17%29%25%18%9%
720
16th to endNight
18%29%31%17%2
768
Page generated at 2017-09-13 07:39:17. Version ac04

Copyright 2017 A. Danko


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