Beckwith Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Beckwith Park clear sky chart from 2005-11-05 to 2017-08-12.

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
28%
14535
13%
46498
8%
14505
35%
14505
16%
33123

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
13%
720
8%
2506
3%
716
20%
716
7%
2007
January16th to endNight
19%
768
12%
2625
6%
768
26%
768
10%
1983
February1st to 15thNight
16%
702
10%
2287
3%
701
24%
701
10%
1758
February16th to endNight
19%
631
13%
1955
6%
631
29%
631
13%
1462
March1st to 15thNight
18%
720
13%
2088
6%
720
26%
720
15%
1546
March16th to endNight
29%
768
19%
2042
9%
768
37%
768
21%
1418
April1st to 15thNight
22%
718
16%
1796
6%
718
27%
718
18%
1327
April16th to endNight
27%
653
18%
1733
7%
653
34%
653
21%
1220
May1st to 15thNight
32%
360
18%
1440
15%
360
43%
360
16%
946
May16th to endNight
32%
375
14%
1497
9%
374
45%
374
19%
931
June1st to 15thNight
34%
360
10%
1440
8%
360
43%
360
14%
967
June16th to endNight
38%
360
9%
1440
10%
360
44%
360
18%
922
July1st to 15thNight
49%
340
15%
1360
21%
340
55%
340
27%
759
July16th to endNight
57%
376
14%
1418
16%
354
62%
354
27%
811
August1st to 15thNight
48%
449
15%
1498
11%
447
54%
447
25%
941
August16th to endNight
49%
646
19%
1696
9%
646
54%
646
37%
1040
September1st to 15thNight
42%
660
16%
1650
7%
660
45%
660
29%
1141
September16th to endNight
46%
657
22%
1796
13%
657
51%
657
30%
1151
October1st to 15thNight
32%
660
17%
1980
11%
660
40%
660
20%
1374
October16th to endNight
24%
704
11%
2189
5%
704
32%
704
13%
1665
November1st to 15thNight
27%
700
17%
2334
12%
700
35%
700
16%
1643
November16th to endNight
19%
720
11%
2520
6%
720
26%
720
10%
1940
December1st to 15thNight
16%
720
7%
2520
3%
720
21%
720
7%
2011
December16th to endNight
12%
768
9%
2688
4%
768
18%
768
7%
2160

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
17%9%36%6%34446%32%
47480
Night
17%10%36%5%24446%33%
46667
Cloud CoverDay
19%8%36%5%34446%33%
47489
Night
18%9%36%5%24445%33%
46673
TransparencyDay
51%6%11%19%10%1
47167
Night
52%5%11%19%10%1
46498
SeeingDay
23%13%29%20%9%3
5325
Night
24%12%29%23%9%
14537

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
19%14%6%10%7%4433321%
1432
16th to endDay
14%15%5%10%8%35%445%22%
1597
February1st to 15thDay
14%13%5%11%8%35%43423%
1575
16th to endDay
18%13%47%7%35%345%25%
1518
March1st to 15thDay
18%11%49%7%45%34427%
1859
16th to endDay
15%9%36%5%3234440%
2181
April1st to 15thDay
22%10%36%423435%33%
2152
16th to endDay
21%7%25%5%24336%37%
2235
May1st to 15thDay
19%8%36%5%2445%6%33%
2511
16th to endDay
16%6%36%5%25%45%7%36%
2618
June1st to 15thDay
21%7%35%5%25%5%47%31%
2520
16th to endDay
16%6%35%6%35%5%6%8%31%
2520
July1st to 15thDay
12%5%245%35%5%7%8%38%
2520
16th to endDay
11%5%25%5%35%5%7%9%37%
2654
August1st to 15thDay
11%7%35%6%445%5%8%37%
2366
16th to endDay
12%5%25%5%445%5%8%40%
2143
September1st to 15thDay
17%5%15%5%335%5%7%40%
1980
16th to endDay
15%5%25%433447%43%
1830
October1st to 15thDay
21%8%25%5%34446%33%
1650
16th to endDay
26%10%37%7%24435%24%
1682
November1st to 15thDay
15%8%36%6%26%5%46%33%
1521
16th to endDay
20%13%48%6%34445%24%
1440
December1st to 15thDay
23%15%5%8%5%44345%18%
1440
16th to endDay
24%14%5%6%6%3444420%
1536
January1st to 15thNight
18%15%5%10%8%45%345%19%
2506
16th to endNight
13%15%6%8%7%34445%25%
2625
February1st to 15thNight
13%14%5%10%7%34445%23%
2285
16th to endNight
15%12%48%7%25%345%29%
1955
March1st to 15thNight
18%11%48%5%34335%30%
2075
16th to endNight
15%8%46%5%2434441%
2042
April1st to 15thNight
21%9%35%5%23245%34%
1796
16th to endNight
17%8%26%5%24336%37%
1733
May1st to 15thNight
21%7%35%5%23445%36%
1440
16th to endNight
15%6%25%425%5%5%7%38%
1495
June1st to 15thNight
19%7%35%6%2445%7%33%
1440
16th to endNight
15%6%25%5%35%5%5%7%37%
1440
July1st to 15thNight
10%325%5%2446%7%47%
1440
16th to endNight
9%4234345%6%9%46%
1514
August1st to 15thNight
9%6%25%5%25%5%6%8%42%
1508
16th to endNight
9%42342435%7%51%
1696
September1st to 15thNight
16%5%26%5%23445%43%
1650
16th to endNight
16%5%23323336%48%
1796
October1st to 15thNight
20%8%35%424447%35%
1980
16th to endNight
26%9%36%5%3335%5%26%
2189
November1st to 15thNight
19%10%35%424445%33%
2334
16th to endNight
22%12%47%6%34345%24%
2520
December1st to 15thNight
21%16%5%7%6%2444421%
2520
16th to endNight
24%15%5%8%7%3333320%
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
19%14%6%10%7%4433322%
1432
16th to endDay
14%15%5%9%8%45%345%22%
1597
February1st to 15thDay
15%13%5%12%7%4444423%
1575
16th to endDay
19%12%5%7%7%35%34425%
1518
March1st to 15thDay
22%9%47%7%3423329%
1869
16th to endDay
19%9%25%42333441%
2180
April1st to 15thDay
22%11%35%42343434%
2152
16th to endDay
21%7%35%423336%37%
2235
May1st to 15thDay
24%8%26%423445%33%
2511
16th to endDay
22%6%25%425%446%35%
2618
June1st to 15thDay
21%6%345%24446%34%
2520
16th to endDay
16%6%25%5%345%5%7%36%
2520
July1st to 15thDay
13%4245%35%5%7%8%38%
2520
16th to endDay
12%5%25%5%36%5%6%9%36%
2654
August1st to 15thDay
19%5%246%34446%38%
2366
16th to endDay
18%325%424447%40%
2143
September1st to 15thDay
17%4246%335%47%41%
1980
16th to endDay
15%5%24423446%44%
1830
October1st to 15thDay
21%8%25%5%34446%33%
1650
16th to endDay
26%10%38%6%2343424%
1682
November1st to 15thDay
16%8%36%5%35%446%35%
1521
16th to endDay
21%12%5%7%6%24345%26%
1440
December1st to 15thDay
23%15%49%6%35%44418%
1440
16th to endDay
25%15%5%7%5%3434321%
1536
January1st to 15thNight
18%15%5%10%8%35%33420%
2506
16th to endNight
14%15%5%9%6%34446%25%
2625
February1st to 15thNight
15%14%5%11%7%3444423%
2278
16th to endNight
17%11%48%6%35%345%28%
1955
March1st to 15thNight
23%9%37%5%2333432%
2088
16th to endNight
18%7%45%42323442%
2042
April1st to 15thNight
21%9%35%5%23325%35%
1796
16th to endNight
19%7%26%424436%38%
1733
May1st to 15thNight
24%6%24413346%36%
1440
16th to endNight
18%6%245%24447%39%
1495
June1st to 15thNight
18%7%35%5%2435%6%35%
1440
16th to endNight
16%5%25%5%245%5%7%39%
1440
July1st to 15thNight
10%325%42445%8%47%
1440
16th to endNight
9%414335%5%6%10%45%
1514
August1st to 15thNight
14%4145%345%5%7%42%
1508
16th to endNight
14%323323346%51%
1696
September1st to 15thNight
16%5%25%5%23445%44%
1650
16th to endNight
16%423323436%48%
1796
October1st to 15thNight
20%8%24424447%35%
1980
16th to endNight
27%10%36%5%33345%26%
2189
November1st to 15thNight
20%9%35%424345%36%
2334
16th to endNight
21%11%46%6%3334429%
2520
December1st to 15thNight
22%15%5%7%6%2443421%
2520
16th to endNight
25%15%5%7%7%2433319%
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
67%38%12%6%1
1433
16th to endDay
63%5%10%11%8%
1597
February1st to 15thDay
64%5%8%16%3
1577
16th to endDay
60%5%10%13%9%
1518
March1st to 15thDay
61%410%14%7%
1869
16th to endDay
46%39%19%14%5%
2181
April1st to 15thDay
54%37%18%14%2
2152
16th to endDay
49%47%19%16%3
2235
May1st to 15thDay
50%5%9%18%14%2
2511
16th to endDay
46%6%11%21%11%1
2622
June1st to 15thDay
52%6%10%20%9%
2520
16th to endDay
48%8%11%19%11%
2520
July1st to 15thDay
37%7%13%28%12%
2371
16th to endDay
43%9%14%23%9%
2487
August1st to 15thDay
45%8%13%21%11%
2352
16th to endDay
39%6%15%26%11%
2143
September1st to 15thDay
42%6%12%27%11%
1980
16th to endDay
40%5%11%31%10%
1830
October1st to 15thDay
52%412%19%9%
1650
16th to endDay
62%5%10%15%5%
1682
November1st to 15thDay
50%7%13%19%9%
1521
16th to endDay
61%5%11%13%6%1
1440
December1st to 15thDay
68%6%11%11%2
1440
16th to endDay
66%6%10%10%5%
1536
January1st to 15thNight
67%49%12%5%
2506
16th to endNight
59%5%8%16%8%
2625
February1st to 15thNight
62%412%15%5%
2287
16th to endNight
57%49%18%9%
1955
March1st to 15thNight
56%410%19%8%
2088
16th to endNight
47%49%19%15%3
2042
April1st to 15thNight
53%36%19%15%1
1796
16th to endNight
47%5%6%19%18%3
1733
May1st to 15thNight
49%5%6%19%14%4
1440
16th to endNight
43%6%12%20%15%2
1497
June1st to 15thNight
50%6%11%20%10%1
1440
16th to endNight
43%7%12%20%14%
1440
July1st to 15thNight
33%6%13%29%15%1
1360
16th to endNight
33%7%16%25%16%
1418
August1st to 15thNight
37%9%15%23%13%1
1498
16th to endNight
32%5%17%31%13%
1696
September1st to 15thNight
42%6%10%30%10%
1650
16th to endNight
38%5%11%32%11%
1796
October1st to 15thNight
48%5%10%22%13%
1980
16th to endNight
59%412%16%6%
2189
November1st to 15thNight
52%5%12%17%10%1
2334
16th to endNight
61%5%10%16%4
2520
December1st to 15thNight
65%5%12%12%3
2520
16th to endNight
68%49%11%5%
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
25%30%20%20%5%
60
16th to endDay
41%18%29%8%2
75
February1st to 15thDay
31%27%32%8%
90
16th to endDay
32%22%28%13%3
177
March1st to 15thDay
26%16%29%22%4
270
16th to endDay
22%19%30%15%8%2
288
April1st to 15thDay
28%20%28%14%6%1
270
16th to endDay
27%17%23%18%6%5%
270
May1st to 15thDay
30%12%27%18%5%4
288
16th to endDay
21%16%33%18%9%1
331
June1st to 15thDay
28%11%29%20%8%1
315
16th to endDay
20%10%33%22%11%1
315
July1st to 15thDay
16%433%27%14%4
305
16th to endDay
13%5%32%27%15%4
326
August1st to 15thDay
15%6%27%31%11%7%
297
16th to endDay
10%5%28%29%14%11%
268
September1st to 15thDay
19%7%24%20%15%12%
255
16th to endDay
16%9%32%17%15%8%
254
October1st to 15thDay
25%12%25%21%10%3
255
16th to endDay
33%13%29%17%5%
257
November1st to 15thDay
20%15%30%22%9%1
175
16th to endDay
33%18%26%16%5%
60
December1st to 15thDay
23%26%33%11%5%
60
16th to endDay
42%25%26%6%
64
January1st to 15thNight
28%19%30%16%4
720
16th to endNight
23%14%34%21%5%
768
February1st to 15thNight
22%19%35%19%3
704
16th to endNight
23%17%35%17%6%
631
March1st to 15thNight
27%14%32%22%2
720
16th to endNight
20%16%27%24%8%1
768
April1st to 15thNight
27%15%29%22%4
718
16th to endNight
24%14%30%20%8%
653
May1st to 15thNight
25%7%28%27%8%1
360
16th to endNight
19%5%37%25%11%
375
June1st to 15thNight
25%7%26%32%8%
360
16th to endNight
18%5%31%30%13%
360
July1st to 15thNight
10%5%27%41%13%1
340
16th to endNight
9%129%42%16%1
376
August1st to 15thNight
12%426%32%21%2
449
16th to endNight
12%327%33%20%1
646
September1st to 15thNight
21%328%25%18%2
660
16th to endNight
19%8%22%25%21%1
657
October1st to 15thNight
24%10%26%25%12%1
660
16th to endNight
30%14%23%23%7%
704
November1st to 15thNight
28%10%30%20%10%
700
16th to endNight
31%16%25%18%7%
720
December1st to 15thNight
31%18%29%17%2
720
16th to endNight
34%14%29%17%2
768
Page generated at 2017-08-13 14:16:52. Version ac04

Copyright 2017 A. Danko


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