Wakefield
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wakefield clear sky chart from 2005-11-05 to 2017-12-02.

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
25%
14939
14%
47816
7%
14907
33%
14907
14%
33886

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
15%
720
7%
2506
3%
716
21%
716
6%
2013
January16th to endNight
15%
768
11%
2643
5%
768
23%
768
9%
1979
February1st to 15thNight
13%
704
12%
2287
3%
701
23%
701
9%
1745
February16th to endNight
17%
631
14%
1955
5%
631
28%
631
10%
1452
March1st to 15thNight
17%
720
14%
2097
6%
720
26%
720
12%
1580
March16th to endNight
23%
768
21%
2037
8%
768
33%
768
18%
1407
April1st to 15thNight
19%
718
16%
1796
5%
718
25%
718
17%
1333
April16th to endNight
21%
636
17%
1716
4%
636
31%
636
17%
1201
May1st to 15thNight
29%
360
18%
1440
15%
360
39%
360
13%
937
May16th to endNight
25%
375
13%
1497
8%
374
39%
374
15%
956
June1st to 15thNight
26%
360
9%
1440
7%
360
37%
360
13%
951
June16th to endNight
36%
360
8%
1440
7%
360
44%
360
14%
914
July1st to 15thNight
47%
340
14%
1360
18%
340
55%
340
24%
747
July16th to endNight
46%
376
14%
1418
15%
354
57%
354
25%
789
August1st to 15thNight
49%
440
15%
1511
12%
438
55%
438
22%
915
August16th to endNight
50%
702
21%
1848
9%
702
57%
702
32%
1147
September1st to 15thNight
41%
720
14%
1800
6%
720
44%
720
27%
1243
September16th to endNight
44%
717
23%
1960
15%
717
49%
717
30%
1248
October1st to 15thNight
29%
720
18%
2160
11%
720
37%
720
19%
1475
October16th to endNight
23%
768
12%
2400
7%
768
31%
768
13%
1800
November1st to 15thNight
24%
760
17%
2541
11%
760
33%
760
15%
1800
November16th to endNight
17%
780
10%
2730
5%
780
25%
780
8%
2098
December1st to 15thNight
14%
728
8%
2546
3%
728
20%
728
7%
2014
December16th to endNight
10%
768
10%
2688
3%
768
19%
768
7%
2142

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
18%9%36%5%34446%31%
48644
Night
17%10%36%5%34445%32%
47985
Cloud CoverDay
24%8%35%5%34345%32%
48653
Night
22%8%35%5%24345%34%
47991
TransparencyDay
52%412%19%9%1
48331
Night
53%411%20%9%
47816
SeeingDay
21%19%27%18%9%3
5702
Night
20%24%23%21%9%
14939

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
21%17%5%9%5%2443421%
1432
16th to endDay
15%16%5%9%7%44445%23%
1579
February1st to 15thDay
12%15%6%11%7%45%435%23%
1575
16th to endDay
17%13%6%8%6%3444425%
1518
March1st to 15thDay
18%11%48%6%44445%27%
1852
16th to endDay
14%8%36%5%34345%39%
2187
April1st to 15thDay
23%10%45%423335%33%
2152
16th to endDay
21%9%35%5%2433436%
2255
May1st to 15thDay
21%8%36%5%34345%33%
2511
16th to endDay
19%6%36%6%34447%32%
2618
June1st to 15thDay
22%6%36%5%35%5%5%7%28%
2520
16th to endDay
18%6%345%36%5%6%7%32%
2520
July1st to 15thDay
14%425%5%35%6%6%9%36%
2520
16th to endDay
12%5%25%6%36%5%6%8%36%
2654
August1st to 15thDay
12%5%26%6%46%5%5%8%35%
2437
16th to endDay
12%5%245%345%6%8%40%
2341
September1st to 15thDay
17%5%25%5%25%45%6%40%
2160
16th to endDay
15%5%2442335%6%45%
1998
October1st to 15thDay
23%7%25%5%24346%33%
1800
16th to endDay
27%10%37%5%34435%24%
1824
November1st to 15thDay
16%10%36%6%345%5%6%31%
1644
16th to endDay
24%12%37%6%43335%23%
1560
December1st to 15thDay
22%16%6%9%7%3445%416%
1451
16th to endDay
23%16%6%8%6%3433419%
1536
January1st to 15thNight
19%17%6%9%7%345%4417%
2506
16th to endNight
13%17%5%8%7%35%345%26%
2643
February1st to 15thNight
12%14%7%10%7%36%5%45%24%
2285
16th to endNight
16%12%5%8%6%35%445%26%
1955
March1st to 15thNight
20%11%47%5%34335%29%
2084
16th to endNight
14%8%37%5%3433441%
2037
April1st to 15thNight
23%8%35%5%23445%33%
1796
16th to endNight
18%9%26%5%24346%36%
1716
May1st to 15thNight
21%9%34424335%36%
1440
16th to endNight
15%7%35%5%25%45%6%37%
1495
June1st to 15thNight
18%6%246%3446%8%33%
1440
16th to endNight
16%6%25%5%35%5%6%7%37%
1440
July1st to 15thNight
11%4144245%5%7%47%
1440
16th to endNight
9%423435%5%6%8%45%
1514
August1st to 15thNight
10%5%26%5%2447%9%41%
1521
16th to endNight
9%315%5%245%46%50%
1848
September1st to 15thNight
14%7%15%5%345%5%5%41%
1800
16th to endNight
17%5%2442224449%
1960
October1st to 15thNight
20%6%26%5%24446%36%
2160
16th to endNight
25%9%26%6%34445%27%
2400
November1st to 15thNight
20%9%35%6%3445%5%31%
2541
16th to endNight
22%12%48%6%34435%23%
2730
December1st to 15thNight
21%15%6%8%8%2444419%
2546
16th to endNight
24%15%6%9%5%3333420%
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
21%16%5%8%6%3433423%
1432
16th to endDay
15%15%5%9%7%43445%25%
1579
February1st to 15thDay
14%14%6%10%6%3433427%
1575
16th to endDay
19%12%5%8%5%3334427%
1518
March1st to 15thDay
34%8%35%5%3333424%
1862
16th to endDay
32%5%25%42223432%
2186
April1st to 15thDay
27%8%35%322225%36%
2152
16th to endDay
24%7%35%32333338%
2255
May1st to 15thDay
33%6%3443322331%
2511
16th to endDay
32%5%235%2333432%
2618
June1st to 15thDay
28%5%25%424436%30%
2520
16th to endDay
25%423435%45%5%34%
2520
July1st to 15thDay
14%425%5%35%6%6%8%36%
2520
16th to endDay
13%5%345%36%5%6%9%36%
2654
August1st to 15thDay
30%4135%35%346%31%
2437
16th to endDay
30%413422346%37%
2341
September1st to 15thDay
17%425%42345%6%42%
2160
16th to endDay
16%5%14423346%47%
1998
October1st to 15thDay
21%7%25%5%23445%36%
1800
16th to endDay
26%9%36%5%3433427%
1824
November1st to 15thDay
20%9%35%5%34445%32%
1644
16th to endDay
27%11%36%7%3324425%
1560
December1st to 15thDay
22%14%6%9%6%2444420%
1451
16th to endDay
24%15%5%7%6%3332323%
1536
January1st to 15thNight
18%16%6%9%6%3444422%
2506
16th to endNight
11%16%6%7%7%24335%30%
2643
February1st to 15thNight
15%12%6%9%6%3443428%
2278
16th to endNight
19%11%47%6%2344429%
1955
March1st to 15thNight
37%7%35%42422326%
2097
16th to endNight
32%6%25%32322335%
2037
April1st to 15thNight
26%8%3441333436%
1796
16th to endNight
20%8%35%5%23245%39%
1716
May1st to 15thNight
27%5%3332323439%
1440
16th to endNight
20%5%24424345%42%
1495
June1st to 15thNight
21%6%245%335%5%6%34%
1440
16th to endNight
20%414435%5%5%6%37%
1440
July1st to 15thNight
11%4144245%5%8%47%
1440
16th to endNight
9%4234345%6%9%45%
1514
August1st to 15thNight
24%32442235%7%38%
1521
16th to endNight
25%2332334444%
1848
September1st to 15thNight
14%6%245%345%45%43%
1800
16th to endNight
17%5%1431223452%
1960
October1st to 15thNight
20%5%25%5%23445%40%
2160
16th to endNight
24%9%25%6%34335%30%
2400
November1st to 15thNight
28%7%2442423433%
2541
16th to endNight
29%9%36%5%2333328%
2730
December1st to 15thNight
22%13%5%6%6%2334425%
2546
16th to endNight
26%13%48%42333425%
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%29%13%5%
1433
16th to endDay
62%410%14%8%
1579
February1st to 15thDay
63%211%17%4
1577
16th to endDay
61%211%13%9%1
1518
March1st to 15thDay
59%311%17%7%1
1862
16th to endDay
47%39%19%15%5%
2187
April1st to 15thDay
55%26%19%12%2
2152
16th to endDay
52%36%20%14%3
2255
May1st to 15thDay
53%37%19%13%1
2511
16th to endDay
51%411%18%11%1
2622
June1st to 15thDay
53%5%11%20%8%
2520
16th to endDay
48%5%13%21%9%1
2520
July1st to 15thDay
41%5%15%26%11%
2371
16th to endDay
44%7%17%22%9%
2487
August1st to 15thDay
45%5%17%22%9%
2423
16th to endDay
39%417%28%9%
2341
September1st to 15thDay
43%413%26%11%
2160
16th to endDay
39%415%31%8%
1998
October1st to 15thDay
52%314%19%9%
1800
16th to endDay
62%412%15%5%
1824
November1st to 15thDay
51%413%20%8%
1644
16th to endDay
64%311%12%6%1
1560
December1st to 15thDay
70%311%12%2
1451
16th to endDay
69%210%11%5%
1536
January1st to 15thNight
69%310%12%4
2506
16th to endNight
61%39%17%8%
2643
February1st to 15thNight
62%39%18%6%
2287
16th to endNight
58%39%18%9%
1955
March1st to 15thNight
59%28%19%8%1
2097
16th to endNight
47%38%20%16%4
2037
April1st to 15thNight
53%36%19%15%1
1796
16th to endNight
49%28%19%16%3
1716
May1st to 15thNight
50%36%20%15%3
1440
16th to endNight
45%5%11%21%13%1
1497
June1st to 15thNight
48%5%11%24%7%1
1440
16th to endNight
44%6%11%21%14%
1440
July1st to 15thNight
33%5%14%29%15%1
1360
16th to endNight
33%6%16%29%13%
1418
August1st to 15thNight
37%7%18%25%10%
1511
16th to endNight
33%5%15%33%11%
1848
September1st to 15thNight
43%5%12%26%12%
1800
16th to endNight
39%211%36%9%
1960
October1st to 15thNight
48%410%25%11%
2160
16th to endNight
58%413%18%5%
2400
November1st to 15thNight
53%413%18%9%
2541
16th to endNight
63%311%16%3
2730
December1st to 15thNight
66%411%14%3
2546
16th to endNight
67%39%13%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
31%23%23%16%5%
60
16th to endDay
33%16%33%8%7%
71
February1st to 15thDay
32%24%35%6%1
90
16th to endDay
33%27%21%14%2
177
March1st to 15thDay
25%25%27%15%4
270
16th to endDay
21%26%28%14%6%2
288
April1st to 15thDay
27%33%20%12%5%
270
16th to endDay
21%30%24%14%8%
270
May1st to 15thDay
28%21%24%13%7%3
288
16th to endDay
21%20%32%15%7%2
331
June1st to 15thDay
23%18%33%17%5%1
315
16th to endDay
18%19%30%21%8%1
315
July1st to 15thDay
15%11%28%28%10%5%
305
16th to endDay
11%13%31%26%13%3
326
August1st to 15thDay
14%11%22%31%13%6%
313
16th to endDay
14%9%27%23%15%8%
332
September1st to 15thDay
18%13%20%21%14%10%
315
16th to endDay
15%14%22%18%19%8%
314
October1st to 15thDay
22%17%26%21%10%1
315
16th to endDay
29%20%26%17%6%
312
November1st to 15thDay
19%19%27%24%8%
208
16th to endDay
28%25%32%12%1
90
December1st to 15thDay
28%14%42%12%1
63
16th to endDay
39%23%34%3
64
January1st to 15thNight
24%29%24%17%4
720
16th to endNight
18%28%27%19%4
768
February1st to 15thNight
17%31%28%18%3
704
16th to endNight
21%30%24%18%5%
631
March1st to 15thNight
24%29%24%18%3
720
16th to endNight
18%31%24%18%7%
768
April1st to 15thNight
23%31%22%18%4
718
16th to endNight
19%32%24%18%5%
636
May1st to 15thNight
22%24%19%23%8%1
360
16th to endNight
17%24%26%21%9%
375
June1st to 15thNight
17%25%23%25%7%
360
16th to endNight
16%21%19%28%12%1
360
July1st to 15thNight
9%15%21%35%17%
340
16th to endNight
8%19%20%34%15%1
376
August1st to 15thNight
13%12%15%35%20%2
440
16th to endNight
11%11%20%32%20%2
702
September1st to 15thNight
17%13%23%25%18%2
720
16th to endNight
17%13%21%23%21%2
717
October1st to 15thNight
23%18%21%23%11%1
720
16th to endNight
27%20%23%21%6%
768
November1st to 15thNight
22%22%25%18%9%1
760
16th to endNight
24%31%20%15%7%
780
December1st to 15thNight
24%30%23%18%2
728
16th to endNight
27%29%23%13%4
768
Page generated at 2017-12-03 11:16:44. Version ac04

Copyright 2017 A. Danko


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