Fenton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fenton 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
36%
15753
15%
46878
10%
15711
42%
15711
20%
32820

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
17%
900
8%
2506
3%
895
22%
895
12%
2021
January16th to endNight
22%
876
9%
2604
4%
876
26%
876
12%
2070
February1st to 15thNight
18%
701
9%
2258
3%
701
25%
701
11%
1758
February16th to endNight
23%
631
13%
1893
7%
631
31%
631
14%
1448
March1st to 15thNight
27%
720
15%
2082
9%
720
32%
720
18%
1509
March16th to endNight
33%
768
18%
2112
10%
768
40%
768
22%
1489
April1st to 15thNight
28%
578
14%
1803
8%
578
35%
578
19%
1260
April16th to endNight
34%
540
21%
1620
9%
540
44%
540
25%
1062
May1st to 15thNight
37%
540
14%
1620
7%
540
43%
540
23%
1107
May16th to endNight
49%
562
16%
1657
12%
561
54%
561
29%
1048
June1st to 15thNight
56%
460
15%
1360
13%
460
60%
460
32%
835
June16th to endNight
56%
483
16%
1383
13%
483
61%
483
34%
843
July1st to 15thNight
64%
510
17%
1360
14%
510
66%
510
40%
810
July16th to endNight
68%
564
18%
1486
15%
531
71%
531
39%
880
August1st to 15thNight
65%
539
20%
1609
16%
536
68%
536
35%
957
August16th to endNight
61%
573
22%
1743
17%
573
65%
573
34%
1021
September1st to 15thNight
58%
648
24%
1885
19%
648
62%
648
35%
1113
September16th to endNight
56%
657
21%
1815
16%
657
60%
657
32%
1127
October1st to 15thNight
45%
660
20%
1894
15%
660
50%
660
26%
1248
October16th to endNight
25%
704
13%
2214
7%
704
33%
704
15%
1594
November1st to 15thNight
35%
700
19%
2276
16%
700
41%
700
21%
1506
November16th to endNight
24%
720
13%
2388
9%
720
30%
720
14%
1758
December1st to 15thNight
15%
759
7%
2559
3%
759
20%
759
10%
2027
December16th to endNight
14%
960
7%
2751
1%
960
19%
960
8%
2329

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
14%9%47%6%3445%7%32%
47748
Night
15%9%46%5%34446%34%
47055
Cloud CoverDay
14%9%47%6%3445%7%32%
47758
Night
15%9%46%5%34446%34%
47059
TransparencyDay
50%5%12%19%10%1
47443
Night
49%5%11%20%11%1
46878
SeeingDay
17%7%26%24%15%7%
5836
Night
19%8%28%29%11%1
15757

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%16%7%12%7%445%45%16%
1432
16th to endDay
15%18%9%11%9%5%433314%
1619
February1st to 15thDay
13%16%6%10%8%5%5%45%5%18%
1602
16th to endDay
12%14%8%12%8%3444421%
1580
March1st to 15thDay
15%11%49%7%34446%27%
1866
16th to endDay
17%11%5%8%6%34335%30%
2112
April1st to 15thDay
20%10%46%5%25%446%30%
2154
16th to endDay
15%7%36%6%23446%37%
2340
May1st to 15thDay
19%8%35%5%2445%6%33%
2331
16th to endDay
14%5%25%5%25%5%5%8%38%
2455
June1st to 15thDay
11%6%26%6%35%5%6%8%38%
2590
16th to endDay
10%5%26%6%45%6%6%8%35%
2567
July1st to 15thDay
8%425%5%35%46%8%43%
2520
16th to endDay
9%325%5%46%7%7%9%38%
2579
August1st to 15thDay
10%5%25%6%47%6%6%8%37%
2340
16th to endDay
11%5%245%35%5%7%7%40%
2457
September1st to 15thDay
12%5%25%5%45%45%8%41%
1982
16th to endDay
14%5%25%5%245%5%9%38%
1815
October1st to 15thDay
15%8%36%6%24437%37%
1735
16th to endDay
22%9%37%5%34335%30%
1656
November1st to 15thDay
15%9%36%5%245%5%7%36%
1582
16th to endDay
16%15%48%5%44447%24%
1569
December1st to 15thDay
15%14%9%11%7%33435%21%
1398
16th to endDay
20%16%9%10%6%1343417%
1467
January1st to 15thNight
21%13%6%8%6%3443422%
2506
16th to endNight
14%12%8%11%8%35%5%46%20%
2604
February1st to 15thNight
15%14%6%9%6%4433425%
2256
16th to endNight
15%13%48%9%34346%25%
1893
March1st to 15thNight
15%11%46%6%34445%32%
2070
16th to endNight
16%7%46%5%35%446%35%
2112
April1st to 15thNight
19%9%345%3446%5%33%
1803
16th to endNight
15%7%25%42345%7%40%
1620
May1st to 15thNight
18%6%25%5%35%45%7%35%
1620
16th to endNight
12%424435%448%44%
1655
June1st to 15thNight
10%4245%2445%9%45%
1360
16th to endNight
9%5%245%2445%10%45%
1383
July1st to 15thNight
7%3245%22449%52%
1440
16th to endNight
5%313425%5%5%10%50%
1588
August1st to 15thNight
6%315%435%5%6%9%47%
1620
16th to endNight
10%324423248%51%
1743
September1st to 15thNight
12%41341435%6%50%
1885
16th to endNight
11%5%25%4245%5%6%45%
1815
October1st to 15thNight
16%6%25%424446%40%
1894
16th to endNight
22%8%26%6%3444431%
2214
November1st to 15thNight
15%8%25%5%245%5%6%38%
2276
16th to endNight
21%12%46%5%33445%27%
2388
December1st to 15thNight
19%15%7%9%5%34345%21%
2559
16th to endNight
20%16%8%11%6%25%34415%
2751

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
15%16%7%11%7%35%445%16%
1432
16th to endDay
15%17%9%11%9%5%433315%
1619
February1st to 15thDay
14%16%6%10%8%46%446%17%
1602
16th to endDay
12%14%8%12%8%34445%21%
1580
March1st to 15thDay
16%11%5%9%7%34447%27%
1877
16th to endDay
17%11%5%8%6%2434430%
2111
April1st to 15thDay
20%10%46%425%445%30%
2154
16th to endDay
16%7%36%5%33446%37%
2340
May1st to 15thDay
20%7%35%5%2445%6%33%
2331
16th to endDay
14%5%25%5%25%5%5%8%38%
2455
June1st to 15thDay
10%6%36%5%35%5%6%8%38%
2590
16th to endDay
10%426%6%45%6%6%9%35%
2567
July1st to 15thDay
8%425%5%35%46%8%43%
2520
16th to endDay
9%425%6%37%6%7%9%38%
2579
August1st to 15thDay
10%5%26%5%46%6%6%8%37%
2340
16th to endDay
11%5%245%45%5%6%7%40%
2457
September1st to 15thDay
12%5%25%5%3445%8%40%
1982
16th to endDay
13%5%25%4246%6%9%38%
1815
October1st to 15thDay
14%8%36%5%24437%37%
1735
16th to endDay
22%10%36%5%33346%30%
1656
November1st to 15thDay
15%9%36%5%335%5%6%36%
1582
16th to endDay
16%14%5%8%5%44446%24%
1569
December1st to 15thDay
15%15%8%12%6%34435%20%
1398
16th to endDay
19%17%9%11%6%2344317%
1467
January1st to 15thNight
21%13%6%8%6%3434422%
2506
16th to endNight
13%12%8%11%7%45%5%45%20%
2604
February1st to 15thNight
15%14%6%9%6%3443425%
2249
16th to endNight
15%13%48%9%34445%26%
1893
March1st to 15thNight
16%11%46%5%34345%32%
2082
16th to endNight
15%8%45%5%35%446%35%
2112
April1st to 15thNight
19%9%345%3445%5%33%
1803
16th to endNight
15%6%25%4245%5%6%40%
1620
May1st to 15thNight
18%6%25%5%25%45%7%35%
1619
16th to endNight
12%4245%34448%44%
1655
June1st to 15thNight
10%42442446%9%45%
1360
16th to endNight
9%5%245%2445%10%45%
1383
July1st to 15thNight
8%31442345%9%52%
1440
16th to endNight
5%313426%46%10%50%
1588
August1st to 15thNight
6%4145%35%5%7%8%47%
1620
16th to endNight
9%424424247%52%
1743
September1st to 15thNight
12%42342335%7%51%
1885
16th to endNight
10%6%25%4245%5%6%46%
1815
October1st to 15thNight
16%6%25%43345%7%40%
1894
16th to endNight
22%8%36%7%34435%31%
2214
November1st to 15thNight
15%8%25%5%25%45%6%38%
2276
16th to endNight
21%12%5%6%5%34445%27%
2388
December1st to 15thNight
19%14%7%9%6%34335%21%
2559
16th to endNight
20%17%8%10%6%25%34415%
2751

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
70%410%10%3
1433
16th to endDay
73%48%8%4
1619
February1st to 15thDay
66%5%10%12%4
1604
16th to endDay
64%49%13%6%1
1580
March1st to 15thDay
56%6%12%16%7%
1877
16th to endDay
56%311%19%7%
2112
April1st to 15thDay
54%5%9%20%10%
2154
16th to endDay
46%415%16%14%2
2340
May1st to 15thDay
50%6%10%20%9%2
2331
16th to endDay
42%5%13%23%12%1
2459
June1st to 15thDay
40%6%13%23%14%1
2590
16th to endDay
42%7%13%20%15%
2567
July1st to 15thDay
36%6%10%26%17%2
2371
16th to endDay
38%7%14%21%15%2
2418
August1st to 15thDay
40%7%13%24%11%1
2327
16th to endDay
39%7%11%24%15%1
2457
September1st to 15thDay
39%6%13%26%12%1
1982
16th to endDay
39%6%12%29%11%
1815
October1st to 15thDay
46%5%11%22%12%1
1735
16th to endDay
55%5%14%18%6%
1656
November1st to 15thDay
46%5%13%22%10%1
1582
16th to endDay
59%5%13%16%5%
1569
December1st to 15thDay
66%411%13%3
1398
16th to endDay
71%411%9%3
1467
January1st to 15thNight
65%410%12%6%
2506
16th to endNight
63%5%12%14%3
2604
February1st to 15thNight
62%5%10%14%6%
2258
16th to endNight
60%410%17%6%
1893
March1st to 15thNight
53%411%19%10%1
2082
16th to endNight
48%5%11%22%9%1
2112
April1st to 15thNight
49%5%11%18%13%
1803
16th to endNight
43%410%20%17%3
1620
May1st to 15thNight
46%5%12%21%10%3
1620
16th to endNight
38%6%12%24%14%3
1657
June1st to 15thNight
34%6%13%28%15%1
1360
16th to endNight
33%6%15%25%17%1
1383
July1st to 15thNight
30%5%9%30%22%2
1360
16th to endNight
29%6%16%23%21%2
1486
August1st to 15thNight
31%6%12%31%14%2
1609
16th to endNight
33%412%29%17%2
1743
September1st to 15thNight
32%5%11%30%18%1
1885
16th to endNight
36%412%28%17%
1815
October1st to 15thNight
42%5%11%23%16%1
1894
16th to endNight
54%412%19%7%
2214
November1st to 15thNight
45%6%12%23%11%1
2276
16th to endNight
57%412%18%6%
2388
December1st to 15thNight
65%411%12%5%
2559
16th to endNight
71%410%9%3
2751

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
15%16%45%18%3
90
16th to endDay
34%8%36%14%6%
96
February1st to 15thDay
31%21%37%10%
90
16th to endDay
19%17%37%20%4
81
March1st to 15thDay
25%12%31%24%5%
167
16th to endDay
26%5%34%21%10%1
288
April1st to 15thDay
23%12%28%25%7%2
270
16th to endDay
19%10%33%18%11%6%
270
May1st to 15thDay
28%8%25%20%13%3
288
16th to endDay
20%7%24%23%15%8%
355
June1st to 15thDay
12%5%33%28%15%4
495
16th to endDay
12%7%32%25%15%6%
495
July1st to 15thDay
10%5%23%30%19%10%
475
16th to endDay
8%422%32%20%11%
439
August1st to 15thDay
13%115%27%22%20%
313
16th to endDay
15%418%19%23%18%
332
September1st to 15thDay
11%5%19%21%26%15%
299
16th to endDay
18%414%22%28%11%
254
October1st to 15thDay
18%6%22%27%18%5%
255
16th to endDay
27%12%30%22%7%
168
November1st to 15thDay
13%14%26%28%14%2
90
16th to endDay
32%16%32%14%4
81
December1st to 15thDay
21%21%38%16%1
60
16th to endDay
24%29%36%9%
85
January1st to 15thNight
27%13%34%18%5%
900
16th to endNight
19%11%35%27%5%
876
February1st to 15thNight
24%12%36%23%3
704
16th to endNight
22%13%30%28%5%
631
March1st to 15thNight
22%12%30%27%6%
720
16th to endNight
18%10%31%29%8%1
768
April1st to 15thNight
22%13%31%25%5%1
578
16th to endNight
19%8%34%27%8%1
540
May1st to 15thNight
21%430%33%8%1
540
16th to endNight
14%425%37%16%2
563
June1st to 15thNight
10%424%47%14%
460
16th to endNight
10%224%45%15%1
483
July1st to 15thNight
10%216%40%26%2
510
16th to endNight
6%216%48%22%3
564
August1st to 15thNight
9%116%41%26%4
539
16th to endNight
11%317%32%29%5%
573
September1st to 15thNight
14%318%32%25%5%
648
16th to endNight
13%5%16%32%27%4
657
October1st to 15thNight
19%6%23%32%16%1
660
16th to endNight
27%10%32%23%5%
704
November1st to 15thNight
20%11%29%26%11%1
700
16th to endNight
26%13%29%23%6%
720
December1st to 15thNight
26%13%36%19%3
759
16th to endNight
28%13%35%19%2
960
Page generated at 2017-09-13 07:39:14. Version ac04

Copyright 2017 A. Danko


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