Bangor
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bangor clear sky chart from 2005-11-06 to 2024-03-18.

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%
23311
16%
80949
7%
23208
36%
23208
16%
54248

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 10thNight
17%
753
18%
4353
5%
737
31%
737
8%
2647
January11th to 20thNight
15%
757
17%
4352
2%
740
28%
740
7%
2675
January21st to endNight
17%
834
11%
4806
4%
814
34%
814
9%
3199
February1st to 10thNight
17%
760
16%
2470
5%
760
31%
760
13%
1724
February11th to 20thNight
13%
743
16%
2306
3%
740
30%
740
14%
1573
February21st to endNight
17%
628
18%
1884
5%
628
33%
628
16%
1304
March1st to 10thNight
16%
760
19%
2269
7%
760
31%
760
16%
1590
March11th to 20thNight
19%
752
15%
2067
5%
752
28%
752
16%
1502
March21st to endNight
22%
792
19%
2178
6%
792
32%
792
19%
1530
April1st to 10thNight
17%
720
16%
1817
4%
720
25%
720
17%
1347
April11th to 20thNight
19%
551
17%
1615
6%
551
29%
551
18%
1112
April21st to endNight
21%
540
13%
1620
4%
540
29%
540
15%
1174
May1st to 10thNight
24%
540
14%
1620
7%
540
31%
540
17%
1158
May11th to 20thNight
20%
532
13%
1594
7%
532
28%
532
16%
1146
May21st to endNight
29%
419
13%
1483
8%
418
39%
418
16%
1020
June1st to 10thNight
28%
360
10%
1260
7%
360
36%
360
14%
921
June11th to 20thNight
37%
360
13%
1260
13%
360
42%
360
21%
825
June21st to endNight
37%
360
8%
1260
8%
360
42%
360
15%
911
July1st to 10thNight
39%
350
11%
1301
11%
350
47%
350
20%
849
July11th to 20thNight
42%
348
12%
1392
14%
348
47%
348
18%
880
July21st to endNight
43%
404
12%
1496
11%
382
50%
382
17%
967
August1st to 10thNight
43%
538
12%
1600
8%
534
46%
534
24%
1056
August11th to 20thNight
39%
532
15%
1596
9%
532
43%
532
21%
1098
August21st to endNight
43%
594
21%
1782
12%
594
48%
594
27%
1115
September1st to 10thNight
40%
720
18%
1887
8%
720
47%
720
33%
1190
September11th to 20thNight
40%
720
22%
1980
12%
720
48%
720
32%
1218
September21st to endNight
37%
720
24%
1980
12%
720
47%
720
27%
1278
October1st to 10thNight
36%
720
19%
2031
10%
720
45%
720
23%
1372
October11th to 20thNight
28%
720
19%
2173
7%
720
41%
720
21%
1438
October21st to endNight
21%
792
14%
2574
6%
792
30%
792
15%
1809
November1st to 10thNight
27%
740
19%
2407
8%
740
41%
740
19%
1571
November11th to 20thNight
23%
781
23%
2513
9%
781
40%
781
18%
1654
November21st to endNight
21%
850
16%
2660
4%
850
34%
850
16%
1771
December1st to 10thNight
17%
850
15%
2774
4%
850
30%
850
15%
1973
December11th to 20thNight
16%
850
16%
3437
4%
849
31%
849
11%
2279
December21st to endNight
12%
921
11%
5152
2%
902
28%
902
8%
3372

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
19%7%36%5%3445%7%37%
78283
Night
18%8%36%5%3445%6%37%
81495
TransparencyDay
46%7%12%21%12%2
77988
Night
47%7%12%20%12%2
81325
SeeingDay
25%17%31%19%7%1
14822
Night
23%14%32%24%6%
23333

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 10thDay
16%9%46%5%3445%5%39%
2517
11th to 20thDay
17%7%36%6%44335%42%
2520
21st to endDay
15%10%5%7%6%345%5%6%35%
2806
February1st to 10thDay
17%10%46%5%25%45%7%34%
1710
11th to 20thDay
14%11%37%7%36%45%6%35%
1761
21st to endDay
14%11%27%7%445%46%35%
1570
March1st to 10thDay
19%10%47%5%35%345%35%
1907
11th to 20thDay
17%9%36%5%34446%38%
2059
21st to endDay
18%10%35%5%345%5%5%37%
2178
April1st to 10thDay
23%9%48%5%33446%31%
2142
11th to 20thDay
20%8%25%5%35%446%38%
2293
21st to endDay
25%9%36%5%33445%33%
2340
May1st to 10thDay
23%8%35%5%35%447%33%
2340
11th to 20thDay
22%7%35%5%34446%36%
2301
21st to endDay
19%7%36%435%5%5%8%36%
2804
June1st to 10thDay
25%7%36%5%35%5%48%29%
2700
11th to 20thDay
20%6%36%5%35%5%5%8%36%
2700
21st to endDay
24%7%36%5%35%6%5%7%29%
2700
July1st to 10thDay
16%6%35%446%5%6%8%39%
2615
11th to 20thDay
14%6%35%6%45%5%7%8%38%
2520
21st to endDay
15%6%25%6%46%5%6%9%35%
2713
August1st to 10thDay
15%6%246%35%5%7%8%38%
2327
11th to 20thDay
15%5%35%6%45%5%6%9%36%
2304
21st to endDay
14%5%25%5%3445%7%45%
2571
September1st to 10thDay
12%4245%35%45%8%48%
2072
11th to 20thDay
15%425%5%33345%52%
1980
21st to endDay
16%6%35%42445%7%44%
1980
October1st to 10thDay
18%6%25%6%3435%6%41%
1928
11th to 20thDay
20%6%25%5%44446%40%
1783
21st to endDay
23%9%36%433446%34%
1782
November1st to 10thDay
18%6%25%6%3445%6%39%
1671
11th to 20thDay
20%6%25%3345%48%39%
1663
21st to endDay
22%7%3442345%5%40%
1520
December1st to 10thDay
23%10%36%6%34446%31%
1402
11th to 20thDay
23%10%25%5%3434437%
1668
21st to endDay
26%9%36%5%34445%33%
2436
January1st to 10thNight
14%10%47%6%34446%38%
4429
11th to 20thNight
14%8%47%7%45%5%5%6%35%
4440
21st to endNight
16%11%49%5%35%5%5%6%32%
4848
February1st to 10thNight
15%10%5%7%6%45%5%6%7%31%
2470
11th to 20thNight
13%11%37%6%45%446%38%
2303
21st to endNight
15%11%46%6%35%45%5%36%
1884
March1st to 10thNight
17%12%46%6%34445%36%
2259
11th to 20thNight
17%10%46%6%35%5%5%6%33%
2066
21st to endNight
18%8%37%5%3445%6%37%
2178
April1st to 10thNight
23%10%46%424345%34%
1817
11th to 20thNight
20%7%36%6%346%5%7%34%
1615
21st to endNight
27%8%35%5%2446%5%31%
1620
May1st to 10thNight
23%8%36%425%46%8%31%
1620
11th to 20thNight
22%5%37%6%35%5%6%7%30%
1593
21st to endNight
17%7%35%5%36%47%7%35%
1482
June1st to 10thNight
23%8%36%6%345%5%8%28%
1260
11th to 20thNight
18%6%26%425%5%6%10%36%
1260
21st to endNight
23%8%35%5%245%5%8%31%
1260
July1st to 10thNight
14%5%35%6%36%5%7%10%36%
1340
11th to 20thNight
13%8%37%435%46%9%38%
1440
21st to endNight
17%6%35%6%35%6%7%7%36%
1584
August1st to 10thNight
13%5%26%5%345%7%8%41%
1612
11th to 20thNight
14%6%26%7%45%6%6%8%35%
1596
21st to endNight
14%5%25%434447%48%
1782
September1st to 10thNight
14%5%2442445%7%50%
1887
11th to 20thNight
16%5%2432335%6%50%
1980
21st to endNight
17%5%244245%6%7%44%
1980
October1st to 10thNight
19%6%245%35%5%5%6%40%
2031
11th to 20thNight
18%6%26%5%3445%7%40%
2173
21st to endNight
26%8%35%434346%34%
2574
November1st to 10thNight
18%7%25%5%4435%5%42%
2407
11th to 20thNight
18%6%245%35%5%5%7%39%
2513
21st to endNight
18%8%345%245%6%7%38%
2660
December1st to 10thNight
23%9%46%5%3445%5%32%
2774
11th to 20thNight
23%8%35%434445%38%
3531
21st to endNight
25%9%35%423445%35%
5227

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 10thDay
46%6%16%23%9%1
2518
11th to 20thDay
43%6%12%25%11%2
2520
21st to endDay
48%6%15%17%13%1
2806
February1st to 10thDay
48%6%12%18%12%3
1710
11th to 20thDay
50%5%10%20%13%1
1769
21st to endDay
49%6%11%19%9%5%
1570
March1st to 10thDay
51%5%11%17%13%3
1910
11th to 20thDay
47%5%11%18%16%3
2059
21st to endDay
48%7%9%16%15%4
2178
April1st to 10thDay
54%6%9%15%13%4
2142
11th to 20thDay
47%6%10%22%14%2
2293
21st to endDay
53%5%8%17%14%4
2340
May1st to 10thDay
51%5%9%19%13%3
2340
11th to 20thDay
48%6%9%20%14%2
2305
21st to endDay
46%8%13%19%11%2
2804
June1st to 10thDay
53%7%12%18%9%1
2700
11th to 20thDay
46%7%11%18%15%2
2700
21st to endDay
53%8%12%17%9%2
2700
July1st to 10thDay
41%8%14%24%11%1
2544
11th to 20thDay
41%9%15%23%11%1
2445
21st to endDay
43%8%15%22%10%1
2561
August1st to 10thDay
41%9%17%25%7%
2314
11th to 20thDay
42%9%14%22%12%
2304
21st to endDay
38%7%13%25%16%1
2571
September1st to 10thDay
33%7%16%27%16%1
2072
11th to 20thDay
36%5%10%26%20%3
1980
21st to endDay
39%6%12%26%17%1
1980
October1st to 10thDay
43%6%12%23%14%1
1928
11th to 20thDay
45%6%14%26%9%1
1783
21st to endDay
50%6%11%21%12%1
1782
November1st to 10thDay
44%6%14%21%13%2
1671
11th to 20thDay
43%6%12%21%15%3
1663
21st to endDay
45%5%17%23%9%1
1520
December1st to 10thDay
53%6%12%19%9%1
1402
11th to 20thDay
51%5%10%19%13%2
1668
21st to endDay
54%6%11%19%8%3
2436
January1st to 10thNight
45%7%15%23%9%1
4429
11th to 20thNight
47%7%15%18%10%2
4440
21st to endNight
51%7%11%20%10%1
4848
February1st to 10thNight
50%7%12%17%12%2
2470
11th to 20thNight
48%5%10%20%14%2
2306
21st to endNight
48%6%9%19%13%4
1884
March1st to 10thNight
50%5%8%21%14%3
2269
11th to 20thNight
50%7%11%15%14%3
2067
21st to endNight
47%6%10%18%17%3
2178
April1st to 10thNight
54%410%14%16%3
1817
11th to 20thNight
47%6%11%21%14%1
1615
21st to endNight
52%7%10%15%12%3
1620
May1st to 10thNight
50%7%10%18%14%1
1620
11th to 20thNight
51%7%11%18%11%2
1594
21st to endNight
47%9%12%19%12%1
1483
June1st to 10thNight
53%9%12%18%8%
1260
11th to 20thNight
42%8%16%19%11%2
1260
21st to endNight
51%10%11%17%8%2
1260
July1st to 10thNight
42%9%17%21%11%
1301
11th to 20thNight
42%9%16%22%11%
1392
21st to endNight
45%8%17%21%8%1
1496
August1st to 10thNight
40%10%17%25%8%
1600
11th to 20thNight
44%10%16%19%11%
1596
21st to endNight
36%8%13%25%17%1
1782
September1st to 10thNight
33%8%15%30%14%1
1887
11th to 20thNight
34%6%12%28%19%2
1980
21st to endNight
38%7%10%29%14%1
1980
October1st to 10thNight
43%7%12%23%13%1
2031
11th to 20thNight
44%6%14%25%10%1
2173
21st to endNight
51%6%11%19%12%1
2574
November1st to 10thNight
44%6%13%22%14%1
2407
11th to 20thNight
44%6%10%22%16%2
2513
21st to endNight
44%7%16%19%13%1
2660
December1st to 10thNight
53%5%11%20%11%
2774
11th to 20thNight
48%6%10%21%15%1
3532
21st to endNight
50%6%13%18%11%2
5227

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 10thDay
31%16%33%18%3
180
11th to 20thDay
32%19%35%11%21
180
21st to endDay
20%23%37%17%3
219
February1st to 10thDay
29%20%28%20%3
370
11th to 20thDay
26%26%35%10%2
413
21st to endDay
27%21%32%18%2
382
March1st to 10thDay
30%22%32%14%2
460
11th to 20thDay
25%24%32%14%41
449
21st to endDay
31%22%27%13%5%3
462
April1st to 10thDay
37%23%24%11%5%2
420
11th to 20thDay
33%23%26%12%6%1
412
21st to endDay
29%22%30%15%41
420
May1st to 10thDay
31%20%31%14%31
423
11th to 20thDay
25%18%36%15%5%1
447
21st to endDay
23%18%34%18%6%
580
June1st to 10thDay
27%15%30%19%7%1
630
11th to 20thDay
23%14%30%22%10%1
630
21st to endDay
27%13%29%23%8%1
630
July1st to 10thDay
20%12%35%22%10%1
539
11th to 20thDay
18%10%41%21%9%2
444
21st to endDay
15%11%39%26%8%2
488
August1st to 10thDay
14%12%33%30%9%1
446
11th to 20thDay
18%10%32%26%11%3
439
21st to endDay
17%13%31%24%12%3
495
September1st to 10thDay
14%12%35%26%10%2
450
11th to 20thDay
22%11%30%19%13%5%
450
21st to endDay
18%15%33%18%9%6%
450
October1st to 10thDay
21%17%26%21%12%4
423
11th to 20thDay
24%17%29%19%8%3
360
21st to endDay
31%17%29%18%5%1
396
November1st to 10thDay
25%16%26%24%7%2
365
11th to 20thDay
30%15%33%15%7%
370
21st to endDay
30%19%26%20%5%
370
December1st to 10thDay
28%21%35%12%4
252
11th to 20thDay
36%24%29%10%11
180
21st to endDay
34%24%26%11%5%1
198
January1st to 10thNight
23%21%34%20%3
760
11th to 20thNight
25%20%32%19%3
760
21st to endNight
19%20%37%20%4
836
February1st to 10thNight
23%19%34%20%3
760
11th to 20thNight
21%23%37%17%2
743
21st to endNight
24%17%36%20%3
628
March1st to 10thNight
27%17%35%20%1
760
11th to 20thNight
24%20%32%19%5%
752
21st to endNight
24%18%31%20%5%1
792
April1st to 10thNight
30%18%32%18%2
720
11th to 20thNight
23%17%37%19%4
551
21st to endNight
31%13%31%20%5%
540
May1st to 10thNight
25%14%33%24%4
540
11th to 20thNight
25%12%37%22%4
532
21st to endNight
20%11%35%29%6%
419
June1st to 10thNight
25%8%32%28%7%
360
11th to 20thNight
21%6%32%33%8%
360
21st to endNight
28%425%37%6%
360
July1st to 10thNight
17%5%35%35%8%
350
11th to 20thNight
16%331%39%11%
348
21st to endNight
19%330%37%11%1
404
August1st to 10thNight
15%5%31%39%9%
538
11th to 20thNight
16%6%31%36%10%1
532
21st to endNight
15%7%28%38%11%1
594
September1st to 10thNight
17%5%33%33%11%1
720
11th to 20thNight
19%10%28%26%14%3
720
21st to endNight
18%10%31%29%11%1
720
October1st to 10thNight
22%9%28%28%13%1
720
11th to 20thNight
22%13%31%25%9%1
720
21st to endNight
30%15%31%19%5%
792
November1st to 10thNight
24%13%31%24%7%1
740
11th to 20thNight
24%16%33%20%7%1
781
21st to endNight
26%19%29%21%4
850
December1st to 10thNight
29%14%34%18%4
850
11th to 20thNight
25%22%32%18%3
850
21st to endNight
29%19%31%17%3
931
Page generated at 2024-03-15 14:01:39. Version ac07

Copyright © 2024 Attilla Danko.


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