Aberdeen Regional Airport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Aberdeen Regional Airport 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
43%
16130
17%
46731
11%
16085
48%
16085
28%
30321

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
35%
900
12%
2547
7%
895
40%
895
19%
1860
January16th to endNight
34%
960
12%
2676
6%
960
38%
960
19%
1958
February1st to 15thNight
35%
879
10%
2288
4%
876
39%
876
21%
1673
February16th to endNight
41%
658
16%
1920
9%
658
47%
658
24%
1327
March1st to 15thNight
38%
645
13%
2085
8%
645
44%
645
21%
1424
March16th to endNight
36%
576
16%
2112
13%
576
44%
576
20%
1389
April1st to 15thNight
36%
539
19%
1765
13%
539
48%
539
27%
1085
April16th to endNight
33%
540
17%
1620
11%
540
42%
540
21%
1134
May1st to 15thNight
40%
540
15%
1620
9%
540
45%
540
30%
1019
May16th to endNight
44%
562
12%
1446
6%
561
46%
561
29%
974
June1st to 15thNight
49%
540
15%
1260
5%
540
53%
540
37%
829
June16th to endNight
59%
540
18%
1260
8%
540
61%
540
55%
717
July1st to 15thNight
61%
510
17%
1240
7%
510
64%
510
52%
715
July16th to endNight
67%
564
23%
1421
11%
531
69%
531
55%
736
August1st to 15thNight
69%
539
20%
1610
16%
536
72%
536
42%
868
August16th to endNight
59%
573
27%
1719
27%
573
66%
573
45%
896
September1st to 15thNight
60%
525
23%
1838
24%
525
67%
525
41%
915
September16th to endNight
52%
492
26%
1815
21%
492
63%
492
33%
955
October1st to 15thNight
41%
583
25%
1903
17%
583
47%
583
27%
1144
October16th to endNight
41%
830
20%
2238
11%
830
45%
830
29%
1471
November1st to 15thNight
41%
875
23%
2284
11%
875
48%
875
33%
1445
November16th to endNight
41%
900
18%
2520
12%
900
46%
900
29%
1620
December1st to 15thNight
29%
900
11%
2664
6%
900
35%
900
17%
1986
December16th to endNight
30%
960
12%
2880
7%
960
36%
960
15%
2181

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
11%6%35%5%3445%7%42%
47903
Night
10%7%35%5%2445%6%44%
46895
Cloud CoverDay
11%6%35%5%3445%7%42%
47913
Night
10%7%35%5%2445%7%44%
46898
Cloud CoverDay
11%6%35%5%3445%7%42%
47914
Night
10%7%35%5%2445%6%44%
46899
Cloud CoverDay
11%6%35%5%3445%7%42%
47912
Night
10%7%35%5%2445%7%44%
46899
TransparencyDay
40%6%15%24%11%1
47584
Night
39%6%14%24%13%1
46731
SeeingDay
13%7%29%32%15%2
6118
Night
13%5%30%37%12%
16132

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
6%10%5%9%7%35%5%6%7%31%
1390
16th to endDay
6%13%6%12%8%45%446%27%
1548
February1st to 15thDay
10%9%5%9%6%4447%6%31%
1575
16th to endDay
6%11%410%7%6%7%46%8%25%
1563
March1st to 15thDay
12%9%38%7%35%35%7%31%
1864
16th to endDay
13%11%48%7%34447%29%
2112
April1st to 15thDay
15%6%25%42435%7%42%
2180
16th to endDay
20%9%35%5%34336%34%
2340
May1st to 15thDay
16%6%25%5%33446%40%
2331
16th to endDay
16%6%25%42445%8%39%
2665
June1st to 15thDay
13%5%26%5%25%46%8%39%
2700
16th to endDay
7%214425%45%8%52%
2700
July1st to 15thDay
32134346%6%9%54%
2643
16th to endDay
5%2123245%6%8%56%
2650
August1st to 15thDay
8%4245%345%6%8%47%
2340
16th to endDay
9%31232335%7%57%
2483
September1st to 15thDay
9%313324337%55%
2006
16th to endDay
13%31232235%7%55%
1815
October1st to 15thDay
14%6%34423346%47%
1716
16th to endDay
16%7%24423246%43%
1631
November1st to 15thDay
9%7%35%413447%47%
1571
16th to endDay
11%9%37%435%5%6%7%36%
1440
December1st to 15thDay
11%10%5%7%8%46%336%31%
1296
16th to endDay
13%11%6%9%7%44346%27%
1344
January1st to 15thNight
9%9%5%7%7%35%5%6%7%32%
2547
16th to endNight
7%11%47%6%45%5%5%6%32%
2676
February1st to 15thNight
8%10%5%8%6%3445%6%34%
2285
16th to endNight
8%8%47%7%35%45%6%39%
1920
March1st to 15thNight
12%8%46%5%25%45%7%36%
2073
16th to endNight
13%9%36%435%346%39%
2112
April1st to 15thNight
13%6%24424347%44%
1765
16th to endNight
18%8%45%5%23346%37%
1620
May1st to 15thNight
12%5%24325%45%7%45%
1620
16th to endNight
9%325%5%35%5%7%8%42%
1445
June1st to 15thNight
12%32433346%9%47%
1260
16th to endNight
4212223448%63%
1260
July1st to 15thNight
5%21232435%7%61%
1314
16th to endNight
321221245%8%65%
1517
August1st to 15thNight
5%21242446%8%56%
1620
16th to endNight
6%21221335%6%63%
1719
September1st to 15thNight
9%412213335%62%
1838
16th to endNight
9%414313346%57%
1815
October1st to 15thNight
15%5%23324345%48%
1903
16th to endNight
14%8%25%324346%45%
2238
November1st to 15thNight
8%6%25%5%24447%47%
2284
16th to endNight
9%6%26%5%2435%7%45%
2520
December1st to 15thNight
9%11%5%9%8%345%5%5%31%
2664
16th to endNight
13%12%5%9%8%35%436%28%
2880

Percentage Cloud Cover NW (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
6%9%5%9%7%35%5%6%8%30%
1391
16th to endDay
6%12%6%13%9%35%446%27%
1548
February1st to 15thDay
10%9%49%7%5%445%6%31%
1575
16th to endDay
6%10%5%9%7%5%7%5%5%9%25%
1563
March1st to 15thDay
12%9%39%7%3435%7%32%
1875
16th to endDay
13%12%48%6%34447%29%
2110
April1st to 15thDay
14%7%25%42435%7%42%
2180
16th to endDay
20%9%36%5%34336%34%
2340
May1st to 15thDay
16%7%25%5%34446%39%
2331
16th to endDay
16%6%25%43345%9%39%
2665
June1st to 15thDay
13%426%4345%6%8%38%
2700
16th to endDay
7%21442445%8%52%
2700
July1st to 15thDay
32135%346%6%9%54%
2643
16th to endDay
5%2133245%6%8%57%
2650
August1st to 15thDay
8%4245%345%5%8%47%
2340
16th to endDay
9%313223346%58%
2483
September1st to 15thDay
9%413324337%55%
2006
16th to endDay
12%313312347%55%
1815
October1st to 15thDay
14%5%34423346%48%
1716
16th to endDay
16%7%25%423247%44%
1631
November1st to 15thDay
9%6%35%413447%47%
1571
16th to endDay
11%9%26%5%345%6%7%36%
1440
December1st to 15thDay
10%11%5%7%8%46%336%31%
1296
16th to endDay
13%12%6%8%7%45%346%27%
1344
January1st to 15thNight
9%9%5%7%7%35%5%5%7%32%
2547
16th to endNight
7%11%47%7%45%5%6%6%32%
2676
February1st to 15thNight
8%10%5%8%6%345%5%6%34%
2278
16th to endNight
8%7%47%6%45%45%7%38%
1920
March1st to 15thNight
12%8%46%5%25%45%7%36%
2085
16th to endNight
13%9%36%425%346%39%
2110
April1st to 15thNight
13%6%2443445%7%44%
1765
16th to endNight
17%9%45%433347%36%
1620
May1st to 15thNight
12%5%24325%45%7%45%
1619
16th to endNight
9%425%436%5%7%7%43%
1446
June1st to 15thNight
11%32432346%10%46%
1260
16th to endNight
321221345%8%63%
1260
July1st to 15thNight
421233335%8%61%
1314
16th to endNight
211231246%8%65%
1517
August1st to 15thNight
5%2134245%6%8%56%
1620
16th to endNight
6%212223346%63%
1719
September1st to 15thNight
9%322212235%62%
1838
16th to endNight
9%414313346%57%
1815
October1st to 15thNight
15%5%23414345%48%
1903
16th to endNight
14%7%25%314337%44%
2238
November1st to 15thNight
7%6%35%5%24447%47%
2284
16th to endNight
9%6%26%5%2445%7%45%
2520
December1st to 15thNight
10%11%5%9%7%445%5%5%31%
2664
16th to endNight
12%12%5%9%8%34445%28%
2880

Percentage Cloud Cover SW (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
6%11%5%9%7%35%5%7%8%30%
1390
16th to endDay
6%13%6%12%8%44446%27%
1548
February1st to 15thDay
10%9%5%9%7%45%46%6%30%
1575
16th to endDay
6%11%5%9%7%5%8%5%6%8%25%
1563
March1st to 15thDay
12%9%49%6%35%35%8%31%
1875
16th to endDay
13%11%48%7%4445%7%29%
2112
April1st to 15thDay
14%6%25%43435%6%42%
2180
16th to endDay
20%9%35%434245%34%
2340
May1st to 15thDay
16%7%35%5%3445%6%39%
2331
16th to endDay
16%6%2442445%8%39%
2665
June1st to 15thDay
13%5%36%425%46%8%38%
2700
16th to endDay
7%31443445%8%52%
2700
July1st to 15thDay
42135%246%6%8%54%
2643
16th to endDay
5%2123145%6%9%56%
2650
August1st to 15thDay
8%4245%345%6%7%47%
2340
16th to endDay
9%31232335%7%57%
2483
September1st to 15thDay
9%413323447%55%
2006
16th to endDay
13%313312347%55%
1815
October1st to 15thDay
14%6%34423346%47%
1716
16th to endDay
17%7%24423346%44%
1631
November1st to 15thDay
9%7%25%42345%6%47%
1571
16th to endDay
11%9%46%335%5%6%7%36%
1440
December1st to 15thDay
11%10%5%8%7%46%335%31%
1296
16th to endDay
13%11%7%9%7%45%436%27%
1344
January1st to 15thNight
9%9%6%6%7%35%5%6%6%32%
2547
16th to endNight
8%11%47%6%45%5%6%6%32%
2676
February1st to 15thNight
8%10%5%8%6%45%45%7%34%
2278
16th to endNight
7%8%47%7%3445%6%39%
1920
March1st to 15thNight
12%8%37%5%25%45%7%36%
2085
16th to endNight
13%9%36%5%34346%39%
2112
April1st to 15thNight
13%6%24423448%44%
1765
16th to endNight
18%9%35%5%23346%37%
1620
May1st to 15thNight
13%5%2443445%7%45%
1619
16th to endNight
9%325%436%5%6%9%41%
1445
June1st to 15thNight
12%33432346%8%48%
1260
16th to endNight
411221345%7%63%
1260
July1st to 15thNight
5%21232445%6%62%
1314
16th to endNight
221231245%8%66%
1517
August1st to 15thNight
5%2134245%6%7%56%
1620
16th to endNight
6%22213347%63%
1719
September1st to 15thNight
9%313212335%62%
1838
16th to endNight
10%314322346%57%
1815
October1st to 15thNight
16%5%23324336%48%
1903
16th to endNight
14%8%24323346%45%
2238
November1st to 15thNight
8%6%35%5%2445%7%47%
2284
16th to endNight
10%6%36%42445%7%44%
2520
December1st to 15thNight
9%11%5%9%7%45%5%45%31%
2664
16th to endNight
13%13%5%9%7%35%445%28%
2880

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
6%11%5%9%7%35%5%6%8%30%
1390
16th to endDay
6%13%7%12%9%44446%27%
1548
February1st to 15thDay
9%10%410%6%45%46%6%31%
1575
16th to endDay
6%11%410%7%6%6%5%6%7%26%
1563
March1st to 15thDay
12%9%39%6%35%45%7%31%
1875
16th to endDay
13%11%5%8%7%44447%29%
2110
April1st to 15thDay
15%6%245%24347%42%
2180
16th to endDay
20%9%35%5%34345%34%
2340
May1st to 15thDay
16%7%35%5%33446%39%
2331
16th to endDay
16%6%25%42445%8%39%
2665
June1st to 15thDay
13%5%36%5%25%46%8%38%
2700
16th to endDay
7%3135%245%5%8%52%
2700
July1st to 15thDay
32134346%6%8%54%
2643
16th to endDay
5%21232446%9%56%
2650
August1st to 15thDay
8%4245%335%6%7%47%
2340
16th to endDay
9%21332345%7%56%
2483
September1st to 15thDay
9%313323447%54%
2006
16th to endDay
13%31331235%6%55%
1815
October1st to 15thDay
14%6%24423346%47%
1716
16th to endDay
16%8%24423336%44%
1631
November1st to 15thDay
9%7%25%42345%6%47%
1571
16th to endDay
11%9%47%326%5%6%7%36%
1440
December1st to 15thDay
12%9%5%8%8%46%435%31%
1296
16th to endDay
13%11%7%9%6%45%446%27%
1344
January1st to 15thNight
9%9%5%6%7%35%6%6%6%31%
2547
16th to endNight
8%11%47%6%35%5%6%6%32%
2676
February1st to 15thNight
8%10%5%8%6%445%5%6%34%
2278
16th to endNight
7%8%47%6%35%45%6%38%
1920
March1st to 15thNight
12%8%37%5%3445%7%36%
2085
16th to endNight
13%9%36%5%34446%39%
2112
April1st to 15thNight
12%6%35%424448%44%
1765
16th to endNight
18%9%35%5%23346%37%
1620
May1st to 15thNight
13%5%24434448%44%
1619
16th to endNight
10%3245%36%5%7%8%41%
1445
June1st to 15thNight
12%32442347%7%48%
1260
16th to endNight
42231435%7%63%
1260
July1st to 15thNight
5%11232445%6%61%
1314
16th to endNight
2211312448%66%
1517
August1st to 15thNight
5%2133245%6%8%55%
1620
16th to endNight
6%21221335%7%62%
1719
September1st to 15thNight
9%412212335%62%
1838
16th to endNight
10%314323346%56%
1815
October1st to 15thNight
16%5%24324336%48%
1903
16th to endNight
14%7%25%323446%44%
2238
November1st to 15thNight
8%6%35%5%24447%47%
2284
16th to endNight
10%6%36%5%24447%44%
2520
December1st to 15thNight
10%11%5%8%7%35%5%45%31%
2664
16th to endNight
13%13%5%9%7%35%345%28%
2880

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
49%7%17%17%7%
1391
16th to endDay
57%7%17%15%2
1548
February1st to 15thDay
52%8%15%18%4
1576
16th to endDay
53%8%15%15%6%
1563
March1st to 15thDay
50%7%15%19%6%
1875
16th to endDay
54%8%16%16%4
2112
April1st to 15thDay
41%5%15%26%9%1
2180
16th to endDay
52%5%12%17%10%
2340
May1st to 15thDay
45%5%11%23%12%1
2331
16th to endDay
41%6%17%24%9%
2669
June1st to 15thDay
41%7%15%25%9%
2700
16th to endDay
27%8%17%29%14%2
2700
July1st to 15thDay
24%7%17%30%15%4
2488
16th to endDay
22%6%19%28%19%3
2483
August1st to 15thDay
32%8%14%27%13%3
2326
16th to endDay
26%6%14%32%16%4
2483
September1st to 15thDay
28%6%15%31%17%
2006
16th to endDay
29%6%16%31%15%
1815
October1st to 15thDay
38%5%14%25%14%2
1716
16th to endDay
42%415%25%10%
1631
November1st to 15thDay
35%6%15%26%15%1
1571
16th to endDay
44%8%18%19%7%1
1440
December1st to 15thDay
54%7%14%17%5%
1296
16th to endDay
58%7%12%14%6%
1344
January1st to 15thNight
49%8%13%18%9%
2547
16th to endNight
48%9%17%17%6%
2676
February1st to 15thNight
48%7%17%17%8%
2288
16th to endNight
43%8%14%21%10%1
1920
March1st to 15thNight
46%6%16%21%7%1
2085
16th to endNight
45%6%15%24%7%
2112
April1st to 15thNight
38%5%13%29%12%
1765
16th to endNight
48%5%9%23%11%1
1620
May1st to 15thNight
36%6%14%24%16%1
1620
16th to endNight
36%9%14%24%13%1
1446
June1st to 15thNight
33%6%16%28%13%2
1260
16th to endNight
18%6%19%30%20%4
1260
July1st to 15thNight
21%5%15%31%20%4
1240
16th to endNight
15%7%16%31%24%5%
1421
August1st to 15thNight
22%8%17%30%16%4
1610
16th to endNight
21%6%12%33%22%3
1719
September1st to 15thNight
24%414%32%21%2
1838
16th to endNight
28%5%13%30%19%2
1815
October1st to 15thNight
37%5%11%26%16%3
1903
16th to endNight
39%5%13%26%13%
2238
November1st to 15thNight
35%414%23%18%2
2284
16th to endNight
38%6%21%22%10%1
2520
December1st to 15thNight
53%7%13%18%6%
2664
16th to endNight
57%5%12%16%7%
2880

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
10%236%40%10%1
90
16th to endDay
18%8%21%33%16%1
96
February1st to 15thDay
18%8%36%31%4
90
16th to endDay
11%12%43%25%7%
81
March1st to 15thDay
17%10%34%27%8%1
90
16th to endDay
19%9%25%21%18%5%
96
April1st to 15thDay
19%13%32%26%7%2
299
16th to endDay
24%11%27%23%10%1
450
May1st to 15thDay
17%11%28%28%13%1
468
16th to endDay
20%8%29%25%13%2
517
June1st to 15thDay
12%7%29%32%15%3
495
16th to endDay
6%7%38%33%12%2
495
July1st to 15thDay
3429%38%20%3
475
16th to endDay
5%423%45%18%1
515
August1st to 15thDay
8%121%40%24%2
493
16th to endDay
9%324%37%21%4
523
September1st to 15thDay
8%7%31%37%12%1
203
16th to endDay
16%6%28%25%16%5%
90
October1st to 15thDay
13%10%30%41%5%
90
16th to endDay
19%8%25%31%13%2
96
November1st to 15thDay
7%428%35%21%2
90
16th to endDay
33%10%26%23%6%
90
December1st to 15thDay
16%8%42%23%7%1
90
16th to endDay
16%15%34%21%10%1
96
January1st to 15thNight
14%7%31%37%8%
900
16th to endNight
13%7%34%38%6%
960
February1st to 15thNight
13%8%30%34%11%1
880
16th to endNight
11%5%32%34%13%3
658
March1st to 15thNight
17%6%30%35%9%
645
16th to endNight
16%6%32%34%9%
576
April1st to 15thNight
15%9%36%28%10%
539
16th to endNight
21%8%32%25%11%
540
May1st to 15thNight
14%5%35%33%10%
540
16th to endNight
12%6%32%37%11%
563
June1st to 15thNight
12%430%40%11%
540
16th to endNight
5%230%48%12%
540
July1st to 15thNight
5%226%46%18%
510
16th to endNight
3124%55%14%
564
August1st to 15thNight
5%220%50%20%
539
16th to endNight
8%226%41%20%1
573
September1st to 15thNight
10%224%45%15%1
525
16th to endNight
11%5%27%36%16%1
492
October1st to 15thNight
18%7%30%32%10%
583
16th to endNight
18%5%29%34%11%
830
November1st to 15thNight
10%8%32%34%12%1
875
16th to endNight
12%7%33%36%10%
900
December1st to 15thNight
14%6%37%30%9%1
900
16th to endNight
19%431%34%10%
960
Page generated at 2017-09-11 18:35:18. Version ac04

Copyright 2017 A. Danko


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