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 2018-02-22.

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%
16884
17%
48913
11%
16839
48%
16839
28%
31683

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
36%
975
12%
2760
8%
970
40%
970
19%
2008
January16th to endNight
36%
1040
12%
2899
7%
1040
39%
1040
20%
2100
February1st to 15thNight
36%
954
11%
2483
5%
951
40%
951
22%
1796
February16th to endNight
41%
688
17%
2006
9%
688
47%
688
24%
1388
March1st to 15thNight
38%
645
13%
2085
8%
645
44%
645
21%
1424
March16th to endNight
37%
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
43%
540
21%
1134
May1st to 15thNight
40%
540
15%
1620
9%
540
45%
540
30%
1019
May16th to endNight
44%
562
12%
1446
5%
561
46%
561
29%
974
June1st to 15thNight
49%
540
15%
1260
5%
540
52%
540
37%
829
June16th to endNight
59%
540
18%
1260
8%
540
61%
540
55%
717
July1st to 15thNight
62%
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
60%
573
27%
1719
27%
573
67%
573
45%
896
September1st to 15thNight
60%
540
23%
1893
24%
540
67%
540
41%
941
September16th to endNight
50%
537
26%
1980
21%
537
62%
537
33%
1050
October1st to 15thNight
40%
636
24%
2076
16%
636
47%
636
28%
1236
October16th to endNight
41%
906
22%
2442
12%
906
46%
906
30%
1585
November1st to 15thNight
41%
950
22%
2480
11%
950
47%
950
32%
1586
November16th to endNight
41%
975
20%
2730
12%
975
47%
975
31%
1725
December1st to 15thNight
30%
975
10%
2886
5%
975
35%
975
18%
2132
December16th to endNight
30%
1040
13%
3120
7%
1040
36%
1040
16%
2350

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%
49346
Night
10%7%35%5%2445%7%44%
49077
Cloud CoverDay
11%6%36%5%3445%7%42%
49356
Night
9%7%35%5%2445%7%44%
49080
Cloud CoverDay
11%6%35%5%3445%7%42%
49357
Night
10%7%35%5%2445%6%44%
49081
Cloud CoverDay
11%6%35%5%3445%7%42%
49355
Night
10%7%35%5%2445%7%44%
49081
TransparencyDay
40%6%15%24%11%1
49027
Night
39%6%14%24%13%1
48913
SeeingDay
13%7%29%32%14%2
6612
Night
12%5%31%37%11%
16886

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%46%5%7%7%29%
1507
16th to endDay
6%13%6%12%9%35%446%28%
1677
February1st to 15thDay
9%9%410%7%4446%6%32%
1710
16th to endDay
7%11%410%7%5%7%46%8%26%
1624
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%
2064
16th to endDay
13%31232225%6%55%
1980
October1st to 15thDay
13%5%24423346%48%
1872
16th to endDay
16%7%25%423247%43%
1779
November1st to 15thDay
10%7%35%413447%46%
1705
16th to endDay
10%8%36%335%5%6%7%37%
1560
December1st to 15thDay
11%10%5%7%8%47%336%30%
1404
16th to endDay
12%11%7%9%8%44346%27%
1456
January1st to 15thNight
9%9%5%7%7%35%5%6%7%32%
2760
16th to endNight
7%10%47%6%45%6%5%7%33%
2899
February1st to 15thNight
8%10%5%8%6%3445%6%35%
2480
16th to endNight
8%8%47%7%35%45%6%39%
2006
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
8%422213336%61%
1893
16th to endNight
10%413313346%56%
1980
October1st to 15thNight
15%5%23323345%49%
2076
16th to endNight
13%8%25%323346%46%
2442
November1st to 15thNight
8%6%35%5%24447%47%
2480
16th to endNight
9%5%26%5%2435%7%46%
2730
December1st to 15thNight
9%11%5%9%8%345%5%5%32%
2886
16th to endNight
12%12%5%9%7%35%436%28%
3120

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%46%5%6%8%29%
1508
16th to endDay
6%12%6%12%9%35%446%28%
1677
February1st to 15thDay
9%9%410%7%5%445%6%32%
1710
16th to endDay
7%10%5%9%7%5%7%5%5%9%26%
1624
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%
2064
16th to endDay
13%313312347%55%
1980
October1st to 15thDay
14%5%24423246%49%
1872
16th to endDay
15%7%25%423247%44%
1779
November1st to 15thDay
10%7%36%413447%46%
1705
16th to endDay
10%9%26%4345%6%7%38%
1560
December1st to 15thDay
10%11%5%7%8%46%436%30%
1404
16th to endDay
12%12%7%8%8%45%346%27%
1456
January1st to 15thNight
9%9%5%7%7%35%5%6%7%32%
2760
16th to endNight
7%10%47%7%45%6%6%7%33%
2899
February1st to 15thNight
8%10%5%8%6%345%5%6%35%
2473
16th to endNight
8%7%47%6%35%35%6%38%
2006
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
8%322312246%61%
1893
16th to endNight
10%41331335%6%56%
1980
October1st to 15thNight
15%5%23424345%49%
2076
16th to endNight
13%7%25%324437%46%
2442
November1st to 15thNight
7%6%35%5%2445%7%46%
2480
16th to endNight
9%6%26%5%2445%7%46%
2730
December1st to 15thNight
9%11%5%9%7%4445%5%32%
2886
16th to endNight
12%12%5%9%8%35%445%28%
3120

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%10%5%9%7%35%5%7%8%28%
1507
16th to endDay
6%12%6%12%9%44446%28%
1677
February1st to 15thDay
9%9%410%7%4446%6%31%
1710
16th to endDay
7%11%49%7%5%8%5%6%7%26%
1624
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%
2064
16th to endDay
13%313312346%55%
1980
October1st to 15thDay
14%5%24423345%48%
1872
16th to endDay
16%7%25%423336%44%
1779
November1st to 15thDay
9%8%25%5%2345%6%46%
1705
16th to endDay
10%9%36%335%5%6%7%37%
1560
December1st to 15thDay
11%10%5%9%7%46%345%30%
1404
16th to endDay
12%11%7%9%7%45%446%27%
1456
January1st to 15thNight
9%9%5%6%7%35%6%6%6%32%
2760
16th to endNight
7%10%47%6%45%5%6%6%33%
2899
February1st to 15thNight
8%10%48%6%3445%7%36%
2473
16th to endNight
8%8%47%7%3445%6%39%
2006
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%313222336%61%
1893
16th to endNight
10%314323346%56%
1980
October1st to 15thNight
15%5%23323346%49%
2076
16th to endNight
13%8%24323446%46%
2442
November1st to 15thNight
8%6%35%5%25%45%7%46%
2480
16th to endNight
9%5%36%42445%7%46%
2730
December1st to 15thNight
9%11%5%9%7%45%5%45%31%
2886
16th to endNight
12%13%5%9%7%34445%28%
3120

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%10%5%10%7%36%5%6%8%29%
1507
16th to endDay
6%12%7%11%9%44346%28%
1677
February1st to 15thDay
9%9%410%6%45%46%5%31%
1710
16th to endDay
6%11%49%6%6%6%5%6%6%27%
1624
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
10%313323447%55%
2064
16th to endDay
14%313312346%55%
1980
October1st to 15thDay
14%5%24422346%48%
1872
16th to endDay
15%8%24423336%44%
1779
November1st to 15thDay
9%8%25%423446%46%
1705
16th to endDay
10%9%36%326%5%6%7%37%
1560
December1st to 15thDay
11%10%5%8%8%46%445%30%
1404
16th to endDay
13%11%7%9%7%45%445%26%
1456
January1st to 15thNight
9%9%5%6%7%35%6%6%6%32%
2760
16th to endNight
8%10%47%6%45%6%6%7%32%
2899
February1st to 15thNight
8%10%48%6%445%5%6%36%
2473
16th to endNight
8%9%47%6%35%45%6%39%
2006
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
8%413312335%61%
1893
16th to endNight
10%314323347%56%
1980
October1st to 15thNight
15%5%23324336%48%
2076
16th to endNight
13%7%25%323446%46%
2442
November1st to 15thNight
8%6%35%5%2445%7%46%
2480
16th to endNight
9%5%26%42445%7%45%
2730
December1st to 15thNight
9%11%5%8%7%35%5%45%31%
2886
16th to endNight
12%13%5%9%7%34445%28%
3120

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
50%8%17%16%7%
1508
16th to endDay
56%6%18%15%2
1677
February1st to 15thDay
52%8%15%19%5%
1711
16th to endDay
53%8%15%15%6%
1624
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%5%15%31%16%
2064
16th to endDay
30%5%15%32%15%
1980
October1st to 15thDay
37%414%26%15%2
1872
16th to endDay
42%415%26%10%
1779
November1st to 15thDay
36%6%14%26%14%1
1705
16th to endDay
42%7%19%20%7%1
1560
December1st to 15thDay
54%7%14%16%5%
1404
16th to endDay
58%7%12%14%7%
1456
January1st to 15thNight
48%8%13%18%9%
2760
16th to endNight
47%9%17%18%6%
2899
February1st to 15thNight
47%7%16%17%10%
2483
16th to endNight
44%7%14%21%10%1
2006
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%20%2
1893
16th to endNight
29%5%13%30%19%2
1980
October1st to 15thNight
36%410%26%17%3
2076
16th to endNight
38%5%13%26%14%1
2442
November1st to 15thNight
36%5%15%23%17%2
2480
16th to endNight
36%6%21%24%10%1
2730
December1st to 15thNight
52%7%14%18%6%
2886
16th to endNight
56%5%12%15%8%
3120

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
9%436%37%9%2
135
16th to endDay
16%6%22%38%14%
144
February1st to 15thDay
14%10%34%35%5%
135
16th to endDay
14%12%44%24%6%
100
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
9%7%29%37%13%2
219
16th to endDay
20%5%32%22%15%3
135
October1st to 15thDay
11%8%42%31%5%
135
16th to endDay
16%11%28%32%9%1
144
November1st to 15thDay
11%5%29%36%14%1
135
16th to endDay
25%12%31%24%5%
135
December1st to 15thDay
16%7%43%25%5%
135
16th to endDay
14%13%38%25%7%
144
January1st to 15thNight
13%7%31%38%8%
975
16th to endNight
12%6%34%39%6%
1040
February1st to 15thNight
13%8%31%34%11%1
955
16th to endNight
12%5%32%34%12%2
688
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%16%1
540
16th to endNight
12%5%29%35%16%1
537
October1st to 15thNight
17%7%31%31%10%
636
16th to endNight
17%6%30%33%11%
906
November1st to 15thNight
10%8%32%35%11%1
950
16th to endNight
11%8%33%36%10%
975
December1st to 15thNight
13%6%37%30%9%1
975
16th to endNight
18%5%31%34%9%
1040
Page generated at 2018-02-23 10:21:38. Version ac04

Copyright 2018 A. Danko


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