Eastport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Eastport clear sky chart from 2005-11-06 to 2024-02-10.

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
29%
23335
15%
80477
7%
23231
38%
23231
16%
55788

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
16%
811
15%
4584
3%
793
27%
793
7%
2904
January11th to 20thNight
14%
757
15%
4344
2%
740
25%
740
6%
2880
January21st to endNight
15%
833
9%
4585
3%
814
29%
814
8%
3144
February1st to 10thNight
17%
759
13%
2464
4%
759
29%
759
12%
1796
February11th to 20thNight
16%
703
12%
2272
2%
700
28%
700
10%
1654
February21st to endNight
19%
592
18%
1776
4%
592
37%
592
16%
1235
March1st to 10thNight
18%
720
18%
2080
6%
720
31%
720
16%
1514
March11th to 20thNight
25%
720
14%
1980
6%
720
32%
720
16%
1460
March21st to endNight
25%
792
19%
2178
7%
792
36%
792
20%
1535
April1st to 10thNight
22%
666
14%
1864
4%
666
30%
666
17%
1370
April11th to 20thNight
29%
534
19%
1598
8%
534
38%
534
20%
1113
April21st to endNight
28%
540
13%
1620
6%
540
35%
540
18%
1182
May1st to 10thNight
32%
540
15%
1620
8%
540
39%
540
20%
1138
May11th to 20thNight
33%
532
15%
1542
10%
532
39%
532
18%
1135
May21st to endNight
39%
541
12%
1510
9%
541
43%
541
21%
1090
June1st to 10thNight
36%
360
10%
1260
9%
360
42%
360
14%
921
June11th to 20thNight
40%
360
13%
1260
12%
360
45%
360
18%
868
June21st to endNight
40%
360
9%
1260
10%
360
42%
360
14%
933
July1st to 10thNight
44%
350
10%
1225
11%
350
48%
350
16%
865
July11th to 20thNight
48%
348
10%
1309
13%
348
50%
348
17%
889
July21st to endNight
46%
515
10%
1601
11%
487
48%
487
16%
1164
August1st to 10thNight
53%
538
11%
1600
11%
534
53%
534
22%
1118
August11th to 20thNight
48%
532
14%
1596
10%
532
50%
532
20%
1138
August21st to endNight
52%
594
20%
1782
14%
594
56%
594
27%
1147
September1st to 10thNight
53%
608
18%
1845
14%
608
57%
608
28%
1161
September11th to 20thNight
48%
720
20%
1980
14%
720
54%
720
30%
1272
September21st to endNight
45%
720
24%
1980
15%
720
51%
720
31%
1264
October1st to 10thNight
41%
720
21%
2101
13%
720
47%
720
25%
1384
October11th to 20thNight
35%
720
20%
2160
9%
720
46%
720
24%
1425
October21st to endNight
25%
792
15%
2492
7%
792
34%
792
17%
1760
November1st to 10thNight
28%
740
18%
2407
8%
740
39%
740
18%
1606
November11th to 20thNight
25%
847
18%
2653
8%
847
37%
847
17%
1788
November21st to endNight
22%
850
14%
2660
4%
850
33%
850
15%
1873
December1st to 10thNight
14%
850
11%
2660
2%
850
24%
850
12%
2033
December11th to 20thNight
13%
850
11%
3460
2%
849
24%
849
9%
2570
December21st to endNight
13%
921
9%
5169
1%
907
25%
907
7%
3459

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%8%35%5%3445%7%36%
77982
Night
20%9%36%5%35%5%5%7%33%
80971
TransparencyDay
47%6%12%21%12%2
77685
Night
51%5%12%20%11%1
80803
SeeingDay
23%9%27%27%13%2
15176
Night
25%11%28%26%10%1
23368

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
19%10%36%6%345%5%7%33%
2283
11th to 20thDay
18%9%47%423435%41%
2520
21st to endDay
15%10%38%5%46%5%6%7%30%
3028
February1st to 10thDay
18%12%36%6%5%5%46%10%26%
1701
11th to 20thDay
17%9%47%5%46%5%6%8%30%
1573
21st to endDay
13%10%45%6%46%46%9%35%
1480
March1st to 10thDay
16%11%37%435%5%5%7%33%
1876
11th to 20thDay
17%8%344345%7%8%37%
1980
21st to endDay
19%8%36%5%3445%6%38%
2178
April1st to 10thDay
20%9%36%6%345%5%6%32%
2092
11th to 20thDay
20%8%2443435%7%39%
2312
21st to endDay
22%7%25%5%2446%6%36%
2340
May1st to 10thDay
23%7%37%5%345%5%7%32%
2340
11th to 20thDay
22%6%25%424447%40%
2349
21st to endDay
19%8%35%4345%6%8%34%
2780
June1st to 10thDay
22%8%35%5%35%45%8%31%
2700
11th to 20thDay
21%7%35%42445%7%37%
2700
21st to endDay
25%8%35%5%345%5%7%29%
2700
July1st to 10thDay
17%6%35%5%35%5%6%9%36%
2700
11th to 20thDay
15%8%25%5%445%6%9%37%
2605
21st to endDay
16%8%35%5%345%6%9%35%
2602
August1st to 10thDay
14%6%25%5%35%6%7%9%39%
2327
11th to 20thDay
16%8%26%5%35%5%5%7%37%
2304
21st to endDay
14%6%244345%5%7%47%
2574
September1st to 10thDay
12%5%2443346%8%49%
2111
11th to 20thDay
16%5%2432345%7%50%
1980
21st to endDay
18%5%25%333347%46%
1980
October1st to 10thDay
16%6%35%6%2445%7%43%
1858
11th to 20thDay
19%6%15%4345%48%41%
1800
21st to endDay
21%6%36%5%3445%5%38%
1859
November1st to 10thDay
21%7%35%424446%39%
1671
11th to 20thDay
21%5%25%42445%9%39%
1525
21st to endDay
22%9%35%5%44446%35%
1520
December1st to 10thDay
25%8%46%7%345%5%6%27%
1520
11th to 20thDay
27%10%36%7%4445%7%24%
1683
21st to endDay
24%9%36%5%35%5%46%30%
2431
January1st to 10thNight
15%11%48%6%3446%6%34%
4652
11th to 20thNight
15%11%48%7%35%45%6%31%
4440
21st to endNight
17%11%47%6%46%6%6%6%28%
4627
February1st to 10thNight
19%10%45%7%36%6%6%6%28%
2464
11th to 20thNight
18%11%37%6%45%5%6%6%29%
2269
21st to endNight
16%10%36%6%3445%6%36%
1776
March1st to 10thNight
16%11%46%6%35%5%45%33%
2071
11th to 20thNight
19%8%36%7%45%5%5%6%30%
1979
21st to endNight
18%10%36%435%45%7%35%
2178
April1st to 10thNight
25%8%37%5%3345%6%31%
1864
11th to 20thNight
23%9%35%4345%5%6%34%
1598
21st to endNight
28%7%35%5%25%348%29%
1620
May1st to 10thNight
23%7%47%6%23347%34%
1620
11th to 20thNight
25%7%35%5%35%5%4433%
1541
21st to endNight
20%9%37%5%445%5%7%32%
1509
June1st to 10thNight
26%8%36%5%35%5%5%7%27%
1260
11th to 20thNight
22%9%37%42445%6%33%
1260
21st to endNight
29%8%35%6%235%47%28%
1260
July1st to 10thNight
18%10%47%5%3447%8%29%
1260
11th to 20thNight
21%9%36%4345%7%9%30%
1352
21st to endNight
21%9%37%5%36%5%5%7%29%
1695
August1st to 10thNight
16%7%45%5%45%5%7%8%34%
1612
11th to 20thNight
19%9%36%5%345%7%8%32%
1596
21st to endNight
17%6%35%4245%5%7%42%
1782
September1st to 10thNight
15%6%245%3446%7%43%
1845
11th to 20thNight
17%7%24424446%47%
1980
21st to endNight
18%7%2442435%7%45%
1980
October1st to 10thNight
18%6%26%43446%7%40%
2101
11th to 20thNight
18%7%25%5%3445%8%39%
2160
21st to endNight
23%9%36%5%34446%35%
2492
November1st to 10thNight
20%7%25%5%35%5%5%5%39%
2407
11th to 20thNight
19%7%36%5%35%45%7%37%
2653
21st to endNight
20%8%36%5%35%5%6%8%33%
2660
December1st to 10thNight
27%10%47%6%3445%6%24%
2660
11th to 20thNight
26%9%35%6%36%5%5%7%25%
3512
21st to endNight
24%9%45%5%3445%6%31%
5236

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
52%419%19%5%1
2284
11th to 20thDay
49%410%25%11%2
2520
21st to endDay
54%7%15%16%8%
3028
February1st to 10thDay
56%414%15%10%1
1701
11th to 20thDay
53%5%14%18%9%1
1581
21st to endDay
45%5%13%23%10%4
1480
March1st to 10thDay
52%311%20%12%2
1880
11th to 20thDay
44%6%11%20%17%3
1980
21st to endDay
47%5%8%21%15%4
2178
April1st to 10thDay
53%5%9%16%15%3
2092
11th to 20thDay
44%5%11%23%15%2
2312
21st to endDay
47%5%9%20%15%3
2340
May1st to 10thDay
53%6%8%19%12%2
2340
11th to 20thDay
45%5%9%25%14%2
2353
21st to endDay
48%7%13%22%9%1
2780
June1st to 10thDay
51%6%12%20%10%1
2700
11th to 20thDay
47%6%10%19%16%2
2700
21st to endDay
54%7%11%16%10%2
2700
July1st to 10thDay
44%7%16%21%11%1
2625
11th to 20thDay
44%8%14%23%10%1
2525
21st to endDay
45%8%15%23%9%1
2456
August1st to 10thDay
40%9%15%26%9%1
2314
11th to 20thDay
46%7%14%22%12%
2304
21st to endDay
36%6%14%26%16%1
2574
September1st to 10thDay
34%6%14%27%17%1
2111
11th to 20thDay
35%5%11%27%18%3
1980
21st to endDay
39%49%30%17%1
1980
October1st to 10thDay
41%6%11%26%15%
1858
11th to 20thDay
42%5%14%29%10%
1800
21st to endDay
48%6%11%22%12%1
1859
November1st to 10thDay
47%6%11%23%13%1
1671
11th to 20thDay
43%5%14%22%14%2
1525
21st to endDay
51%6%15%21%7%1
1520
December1st to 10thDay
59%5%13%16%6%1
1520
11th to 20thDay
61%5%12%14%7%1
1683
21st to endDay
55%7%13%14%9%2
2431
January1st to 10thNight
51%5%15%23%6%1
4652
11th to 20thNight
54%5%12%19%9%1
4440
21st to endNight
55%6%15%18%6%
4627
February1st to 10thNight
56%413%15%10%1
2464
11th to 20thNight
56%5%11%17%9%2
2272
21st to endNight
50%411%19%13%2
1776
March1st to 10thNight
54%49%18%14%2
2080
11th to 20thNight
54%411%14%14%2
1980
21st to endNight
48%5%8%21%15%2
2178
April1st to 10thNight
54%49%15%13%4
1864
11th to 20thNight
50%5%9%20%16%1
1598
21st to endNight
55%410%15%14%2
1620
May1st to 10thNight
52%49%20%14%2
1620
11th to 20thNight
54%5%8%19%11%2
1542
21st to endNight
51%5%12%19%11%1
1510
June1st to 10thNight
56%6%11%19%7%1
1260
11th to 20thNight
52%410%21%11%2
1260
21st to endNight
58%5%9%17%7%3
1260
July1st to 10thNight
53%6%13%16%11%
1225
11th to 20thNight
50%6%15%17%11%1
1309
21st to endNight
53%7%12%17%9%1
1601
August1st to 10thNight
45%9%13%23%10%
1600
11th to 20thNight
50%6%13%22%7%
1596
21st to endNight
41%5%11%26%16%1
1782
September1st to 10thNight
39%6%11%27%16%2
1845
11th to 20thNight
40%411%24%20%1
1980
21st to endNight
39%49%29%17%2
1980
October1st to 10thNight
42%6%9%26%15%2
2101
11th to 20thNight
43%5%13%26%11%1
2160
21st to endNight
52%5%11%20%12%1
2492
November1st to 10thNight
47%5%13%21%13%1
2407
11th to 20thNight
48%5%14%19%13%1
2653
21st to endNight
51%5%15%19%8%1
2660
December1st to 10thNight
62%312%16%7%
2660
11th to 20thNight
58%5%13%16%8%1
3513
21st to endNight
54%5%15%16%7%3
5236

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
26%18%32%19%6%
180
11th to 20thDay
27%18%36%14%41
180
21st to endDay
19%15%36%24%5%1
350
February1st to 10thDay
25%17%33%20%5%1
367
11th to 20thDay
23%18%38%17%41
336
21st to endDay
16%17%37%25%5%
346
March1st to 10thDay
21%16%37%21%5%
420
11th to 20thDay
19%17%33%21%9%
420
21st to endDay
23%14%30%25%6%2
462
April1st to 10thDay
28%13%30%22%5%2
420
11th to 20thDay
23%10%34%24%9%
412
21st to endDay
26%6%29%27%10%2
420
May1st to 10thDay
26%6%31%26%10%1
423
11th to 20thDay
22%428%29%16%1
495
21st to endDay
26%427%28%13%2
680
June1st to 10thDay
26%325%32%12%2
630
11th to 20thDay
23%422%30%18%3
630
21st to endDay
30%319%29%15%4
630
July1st to 10thDay
21%218%39%16%2
620
11th to 20thDay
21%217%33%23%4
524
21st to endDay
18%218%39%20%2
488
August1st to 10thDay
15%218%38%24%3
446
11th to 20thDay
23%214%37%21%3
439
21st to endDay
18%319%33%22%4
495
September1st to 10thDay
14%220%41%20%2
450
11th to 20thDay
21%6%23%26%20%4
450
21st to endDay
18%5%24%32%16%5%
450
October1st to 10thDay
19%10%20%29%19%3
389
11th to 20thDay
19%7%27%29%14%3
360
21st to endDay
24%10%33%22%9%1
396
November1st to 10thDay
22%14%29%23%10%2
365
11th to 20thDay
23%15%32%22%7%1
370
21st to endDay
24%18%34%19%41
370
December1st to 10thDay
29%13%35%18%41
370
11th to 20thDay
32%20%30%14%4
195
21st to endDay
23%19%36%15%5%2
198
January1st to 10thNight
26%18%31%21%3
823
11th to 20thNight
27%18%33%18%4
760
21st to endNight
22%18%38%18%5%
836
February1st to 10thNight
27%18%34%18%4
759
11th to 20thNight
25%21%31%18%31
703
21st to endNight
21%18%34%22%5%1
592
March1st to 10thNight
23%13%39%22%3
720
11th to 20thNight
22%16%30%26%5%1
720
21st to endNight
21%14%32%25%7%1
792
April1st to 10thNight
29%12%31%22%5%
666
11th to 20thNight
27%434%28%7%1
534
21st to endNight
31%429%25%10%
540
May1st to 10thNight
26%5%28%29%10%2
540
11th to 20thNight
28%228%31%10%1
532
21st to endNight
23%426%33%12%2
542
June1st to 10thNight
31%418%35%11%1
360
11th to 20thNight
26%319%34%17%1
360
21st to endNight
33%212%38%14%1
360
July1st to 10thNight
24%117%40%17%
350
11th to 20thNight
26%313%36%20%1
348
21st to endNight
24%214%41%18%2
515
August1st to 10thNight
18%315%43%21%1
538
11th to 20thNight
23%314%38%20%2
532
21st to endNight
19%316%36%23%3
594
September1st to 10thNight
19%217%39%20%2
608
11th to 20thNight
20%422%30%20%4
720
21st to endNight
21%423%32%17%3
720
October1st to 10thNight
22%5%23%30%17%2
720
11th to 20thNight
20%10%29%25%13%2
720
21st to endNight
29%13%29%22%7%
792
November1st to 10thNight
24%12%31%23%9%1
740
11th to 20thNight
23%14%33%21%8%1
847
21st to endNight
26%18%30%19%7%1
850
December1st to 10thNight
34%12%33%16%4
850
11th to 20thNight
27%22%35%13%3
850
21st to endNight
29%18%33%16%4
935
Page generated at 2024-02-07 06:11:55. Version ac07

Copyright 2024 Attilla Danko


Eastport Clear Sky Chart |Charts Home