Aliquippa
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Aliquippa clear sky chart from 2005-11-05 to 2017-09-10.

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%
15144
16%
46868
11%
15106
42%
15106
20%
32388

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
14%
716
10%
2327
4%
716
21%
716
8%
1885
January16th to endNight
16%
768
10%
2496
4%
768
24%
768
10%
1949
February1st to 15thNight
18%
703
10%
2287
6%
701
24%
701
11%
1763
February16th to endNight
17%
631
13%
1949
5%
631
26%
631
13%
1478
March1st to 15thNight
24%
720
15%
1980
7%
720
31%
720
16%
1489
March16th to endNight
25%
768
19%
2112
9%
768
34%
768
21%
1474
April1st to 15thNight
26%
718
13%
1856
4%
718
31%
718
20%
1364
April16th to endNight
35%
579
20%
1659
9%
579
42%
579
26%
1089
May1st to 15thNight
42%
540
15%
1620
10%
540
47%
540
20%
1107
May16th to endNight
53%
471
17%
1594
15%
471
58%
471
27%
969
June1st to 15thNight
51%
360
16%
1440
16%
360
59%
360
26%
797
June16th to endNight
55%
360
17%
1440
19%
360
62%
360
24%
839
July1st to 15thNight
57%
445
14%
1465
13%
445
61%
445
28%
911
July16th to endNight
66%
564
17%
1595
14%
531
69%
531
35%
938
August1st to 15thNight
66%
539
21%
1609
16%
536
69%
536
36%
934
August16th to endNight
66%
633
24%
1779
18%
633
68%
633
37%
1060
September1st to 15thNight
60%
700
25%
1808
16%
700
64%
700
36%
1136
September16th to endNight
53%
657
25%
1815
18%
657
57%
657
32%
1148
October1st to 15thNight
46%
660
20%
1975
18%
660
50%
660
25%
1280
October16th to endNight
28%
704
17%
2112
10%
704
38%
704
19%
1477
November1st to 15thNight
41%
700
22%
2228
18%
700
48%
700
26%
1411
November16th to endNight
24%
720
14%
2520
9%
720
32%
720
14%
1803
December1st to 15thNight
20%
720
9%
2520
6%
720
24%
720
9%
1977
December16th to endNight
15%
768
10%
2682
4%
768
23%
768
10%
2110

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
16%9%36%6%35%45%7%30%
47740
Night
16%9%36%5%2445%6%34%
47060
Cloud CoverDay
17%9%36%5%35%45%7%31%
47750
Night
16%9%36%5%2445%6%34%
47064
TransparencyDay
52%411%20%10%1
47450
Night
49%311%21%11%1
46868
SeeingDay
21%9%24%22%14%6%
5397
Night
21%10%25%27%13%1
15151

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%6%9%5%2433419%
1611
16th to endDay
17%17%8%11%7%34435%17%
1728
February1st to 15thDay
18%16%5%10%7%44335%19%
1575
16th to endDay
17%14%5%9%6%34446%24%
1523
March1st to 15thDay
20%11%48%6%34446%25%
1969
16th to endDay
19%10%35%6%245%5%7%29%
2112
April1st to 15thDay
20%10%36%5%3345%7%30%
2090
16th to endDay
19%8%35%5%24446%35%
2312
May1st to 15thDay
19%8%36%6%36%5%5%7%28%
2331
16th to endDay
14%425%6%45%6%6%8%35%
2518
June1st to 15thDay
15%5%35%5%35%5%6%9%35%
2520
16th to endDay
15%5%25%5%35%6%7%10%32%
2520
July1st to 15thDay
12%7%37%6%345%48%35%
2403
16th to endDay
11%5%16%7%46%6%7%9%34%
2465
August1st to 15thDay
10%426%7%46%6%7%9%31%
2340
16th to endDay
11%425%6%36%5%6%9%37%
2411
September1st to 15thDay
15%5%25%42445%7%41%
2037
16th to endDay
17%6%25%5%34446%39%
1815
October1st to 15thDay
17%7%35%5%35%45%7%35%
1653
16th to endDay
22%8%25%434445%32%
1760
November1st to 15thDay
12%8%36%5%35%446%39%
1627
16th to endDay
20%13%46%5%34436%27%
1440
December1st to 15thDay
22%15%8%10%5%2432417%
1440
16th to endDay
22%18%7%9%6%33235%16%
1540
January1st to 15thNight
22%15%5%10%6%3443319%
2327
16th to endNight
18%14%6%10%7%2434422%
2496
February1st to 15thNight
18%13%5%9%6%35%45%423%
2285
16th to endNight
18%12%5%9%6%25%5%45%24%
1949
March1st to 15thNight
21%10%46%5%2445%6%28%
1968
16th to endNight
16%10%35%5%24445%36%
2112
April1st to 15thNight
18%9%45%6%25%45%6%32%
1856
16th to endNight
14%7%27%42435%7%39%
1659
May1st to 15thNight
16%6%35%5%35%6%5%8%33%
1620
16th to endNight
11%5%24435%5%5%10%42%
1592
June1st to 15thNight
8%5%245%3445%9%45%
1440
16th to endNight
9%435%5%35%45%9%42%
1440
July1st to 15thNight
7%426%5%36%5%5%8%41%
1554
16th to endNight
8%3244345%7%10%44%
1703
August1st to 15thNight
6%425%4245%8%9%46%
1620
16th to endNight
10%4144235%6%7%49%
1779
September1st to 15thNight
13%41332445%7%49%
1808
16th to endNight
14%5%2432445%8%43%
1815
October1st to 15thNight
16%5%25%4345%46%41%
1975
16th to endNight
23%7%15%424445%34%
2112
November1st to 15thNight
17%6%24424347%41%
2228
16th to endNight
21%11%47%5%245%4429%
2520
December1st to 15thNight
23%15%6%9%5%24345%20%
2520
16th to endNight
22%16%6%8%5%24346%19%
2682

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%6%10%5%3433419%
1611
16th to endDay
18%16%8%9%7%43435%17%
1728
February1st to 15thDay
19%16%6%10%6%5%433419%
1575
16th to endDay
17%13%5%10%6%34445%24%
1523
March1st to 15thDay
21%10%5%7%6%34446%25%
1980
16th to endDay
18%10%35%6%2446%7%28%
2111
April1st to 15thDay
19%10%45%5%34446%30%
2090
16th to endDay
20%7%36%434346%35%
2312
May1st to 15thDay
19%8%25%6%36%5%5%8%28%
2331
16th to endDay
14%5%25%5%46%5%7%8%35%
2518
June1st to 15thDay
14%5%245%35%5%6%9%35%
2520
16th to endDay
15%5%25%5%35%5%6%9%33%
2520
July1st to 15thDay
12%7%36%5%4445%7%36%
2403
16th to endDay
11%426%6%46%6%7%9%34%
2465
August1st to 15thDay
11%5%25%7%46%6%6%10%32%
2340
16th to endDay
12%425%6%35%6%6%8%38%
2411
September1st to 15thDay
15%6%24325%45%7%42%
2037
16th to endDay
17%5%36%5%3445%6%39%
1815
October1st to 15thDay
18%6%35%5%3445%7%35%
1653
16th to endDay
23%8%25%434446%32%
1760
November1st to 15thDay
13%8%36%5%245%46%39%
1627
16th to endDay
20%12%47%6%23446%26%
1440
December1st to 15thDay
22%16%8%10%5%3432417%
1440
16th to endDay
23%18%7%8%5%35%225%17%
1540
January1st to 15thNight
23%15%5%9%6%4443319%
2327
16th to endNight
18%13%6%9%7%3434422%
2496
February1st to 15thNight
18%13%5%10%6%35%445%23%
2278
16th to endNight
18%12%5%8%7%25%45%425%
1949
March1st to 15thNight
21%10%5%6%42445%6%28%
1980
16th to endNight
17%10%35%5%33445%37%
2112
April1st to 15thNight
19%8%36%5%34446%32%
1856
16th to endNight
14%7%26%5%24447%40%
1659
May1st to 15thNight
16%7%26%5%26%45%9%32%
1619
16th to endNight
11%5%24425%5%6%8%42%
1592
June1st to 15thNight
9%4244345%6%8%45%
1440
16th to endNight
9%435%445%5%5%8%43%
1440
July1st to 15thNight
7%5%36%5%35%6%6%7%42%
1554
16th to endNight
8%423435%5%7%9%44%
1703
August1st to 15thNight
6%424425%5%8%8%46%
1620
16th to endNight
10%4133345%5%8%48%
1779
September1st to 15thNight
13%413414447%48%
1808
16th to endNight
14%5%23425%35%8%43%
1815
October1st to 15thNight
16%5%25%434446%42%
1975
16th to endNight
24%6%25%435%345%34%
2112
November1st to 15thNight
17%5%24425%347%41%
2228
16th to endNight
21%10%46%5%2445%429%
2520
December1st to 15thNight
23%15%6%8%5%24345%20%
2520
16th to endNight
22%16%6%7%5%24446%19%
2682

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
68%39%12%5%
1612
16th to endDay
69%312%12%2
1728
February1st to 15thDay
68%29%13%5%
1577
16th to endDay
61%411%15%7%
1523
March1st to 15thDay
59%311%18%5%
1980
16th to endDay
53%311%20%9%1
2112
April1st to 15thDay
54%210%19%11%
2090
16th to endDay
49%49%19%13%3
2312
May1st to 15thDay
54%411%19%8%1
2331
16th to endDay
43%5%16%22%10%1
2522
June1st to 15thDay
43%5%13%25%11%
2520
16th to endDay
44%5%13%23%11%
2520
July1st to 15thDay
47%49%20%14%2
2263
16th to endDay
42%6%12%24%12%
2310
August1st to 15thDay
44%5%12%27%10%
2327
16th to endDay
40%411%26%13%3
2411
September1st to 15thDay
41%310%26%16%2
2037
16th to endDay
46%37%25%16%
1815
October1st to 15thDay
47%410%21%14%
1653
16th to endDay
52%313%20%9%
1760
November1st to 15thDay
45%310%22%14%3
1627
16th to endDay
58%211%18%7%1
1440
December1st to 15thDay
71%29%11%3
1440
16th to endDay
72%310%10%3
1540
January1st to 15thNight
69%27%14%5%
2327
16th to endNight
65%211%15%5%
2496
February1st to 15thNight
62%39%16%6%
2287
16th to endNight
60%29%19%6%
1949
March1st to 15thNight
56%311%19%8%
1980
16th to endNight
49%211%23%11%2
2112
April1st to 15thNight
52%39%18%15%
1856
16th to endNight
43%311%21%14%5%
1659
May1st to 15thNight
47%6%10%21%13%1
1620
16th to endNight
38%5%14%23%15%2
1594
June1st to 15thNight
35%5%16%27%15%
1440
16th to endNight
38%5%13%22%17%2
1440
July1st to 15thNight
37%6%13%22%17%2
1465
16th to endNight
32%5%15%26%15%4
1595
August1st to 15thNight
31%5%14%28%18%1
1609
16th to endNight
31%5%11%30%16%4
1779
September1st to 15thNight
33%5%10%24%21%4
1808
16th to endNight
38%38%27%20%1
1815
October1st to 15thNight
42%411%24%14%2
1975
16th to endNight
51%210%23%10%1
2112
November1st to 15thNight
42%311%21%15%5%
2228
16th to endNight
57%28%21%9%1
2520
December1st to 15thNight
66%310%13%4
2520
16th to endNight
66%311%15%3
2682

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
27%23%32%7%44
90
16th to endDay
28%32%30%7%2
96
February1st to 15thDay
34%26%34%4
90
16th to endDay
25%18%39%15%1
93
March1st to 15thDay
29%13%30%19%6%
270
16th to endDay
23%17%32%16%7%2
288
April1st to 15thDay
28%11%26%21%8%1
270
16th to endDay
22%9%31%17%12%5%
270
May1st to 15thDay
28%13%25%18%10%3
288
16th to endDay
19%8%25%22%15%9%
331
June1st to 15thDay
14%7%23%29%19%5%
315
16th to endDay
18%6%27%29%13%4
315
July1st to 15thDay
20%222%28%16%9%
305
16th to endDay
12%217%29%23%14%
326
August1st to 15thDay
15%217%26%23%14%
313
16th to endDay
12%216%27%22%18%
332
September1st to 15thDay
18%316%26%22%12%
294
16th to endDay
19%5%14%24%24%11%
254
October1st to 15thDay
16%6%24%28%20%4
255
16th to endDay
24%12%33%22%7%
272
November1st to 15thDay
17%12%24%18%24%2
145
16th to endDay
26%11%41%11%6%1
60
December1st to 15thDay
28%28%20%15%35%
60
16th to endDay
46%16%26%10%
65
January1st to 15thNight
32%17%29%17%3
720
16th to endNight
25%17%32%22%2
768
February1st to 15thNight
26%18%29%23%2
704
16th to endNight
25%15%33%21%3
631
March1st to 15thNight
28%16%24%25%5%
720
16th to endNight
23%13%31%22%8%1
768
April1st to 15thNight
26%13%29%23%6%
718
16th to endNight
16%8%32%30%10%1
579
May1st to 15thNight
18%8%22%37%11%1
540
16th to endNight
13%323%33%23%3
473
June1st to 15thNight
10%425%41%18%
360
16th to endNight
11%125%35%25%
360
July1st to 15thNight
7%22%41%23%4
445
16th to endNight
9%113%37%33%4
564
August1st to 15thNight
8%114%42%27%5%
539
16th to endNight
12%112%34%33%5%
633
September1st to 15thNight
16%413%33%29%3
700
16th to endNight
16%5%18%25%28%5%
657
October1st to 15thNight
18%8%20%30%20%2
660
16th to endNight
27%12%28%23%7%
704
November1st to 15thNight
20%8%25%29%14%1
700
16th to endNight
29%14%25%20%9%
720
December1st to 15thNight
32%15%25%21%5%
720
16th to endNight
29%15%32%20%1
768
Page generated at 2017-09-11 19:35:29. Version ac04

Copyright 2017 A. Danko


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