Blanc-Sablon
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Blanc-Sablon clear sky chart from 2005-11-06 to 2024-01-16.

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
24%
23485
9%
74458
4%
23421
30%
23421
12%
56905

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
18%
848
12%
2839
3%
847
28%
847
11%
2152
January11th to 20thNight
17%
829
12%
2630
3%
829
27%
829
12%
1975
January21st to endNight
21%
880
14%
2772
4%
880
31%
880
13%
2056
February1st to 10thNight
25%
800
13%
2520
5%
800
33%
800
16%
1786
February11th to 20thNight
21%
738
10%
2318
3%
736
28%
736
14%
1698
February21st to endNight
29%
592
15%
1776
6%
592
36%
592
19%
1250
March1st to 10thNight
23%
717
12%
2159
5%
717
30%
717
14%
1624
March11th to 20thNight
28%
671
12%
2111
8%
671
33%
671
14%
1596
March21st to endNight
23%
594
12%
1993
7%
594
31%
594
12%
1517
April1st to 10thNight
21%
540
8%
1800
6%
540
27%
540
8%
1458
April11th to 20thNight
27%
534
12%
1652
10%
534
31%
534
15%
1237
April21st to endNight
30%
540
11%
1544
7%
540
33%
540
15%
1193
May1st to 10thNight
29%
540
6%
1440
3%
540
31%
540
13%
1169
May11th to 20thNight
31%
532
5%
1336
2%
532
33%
532
15%
1079
May21st to endNight
27%
582
4%
1356
2%
582
28%
582
15%
1129
June1st to 10thNight
27%
540
0%
1260
0%
540
27%
540
12%
1080
June11th to 20thNight
32%
389
0%
1109
0%
389
32%
389
10%
909
June21st to endNight
32%
360
0%
1080
0%
360
32%
360
11%
885
July1st to 10thNight
26%
375
1%
1075
1%
375
27%
375
10%
893
July11th to 20thNight
31%
522
2%
1226
2%
522
31%
522
14%
1020
July21st to endNight
33%
590
3%
1486
2%
558
34%
558
10%
1269
August1st to 10thNight
35%
538
3%
1422
1%
534
35%
534
14%
1161
August11th to 20thNight
33%
532
7%
1458
4%
532
34%
532
13%
1186
August21st to endNight
37%
594
9%
1829
6%
594
39%
594
14%
1399
September1st to 10thNight
30%
540
9%
1800
6%
540
36%
540
14%
1302
September11th to 20thNight
23%
540
10%
1907
5%
540
31%
540
14%
1373
September21st to endNight
24%
540
11%
1980
7%
540
31%
540
13%
1417
October1st to 10thNight
25%
631
12%
2071
4%
631
32%
631
13%
1534
October11th to 20thNight
27%
805
14%
2330
6%
805
33%
805
15%
1772
October21st to endNight
23%
891
10%
2574
4%
891
27%
891
12%
2003
November1st to 10thNight
16%
830
11%
2436
2%
830
24%
830
12%
1867
November11th to 20thNight
20%
850
9%
2831
3%
850
27%
850
12%
2121
November21st to endNight
14%
850
10%
2850
3%
850
22%
850
9%
2249
December1st to 10thNight
17%
850
8%
2850
3%
850
23%
850
9%
2280
December11th to 20thNight
18%
850
9%
3497
4%
849
25%
849
9%
2670
December21st to endNight
23%
931
7%
5141
7%
907
30%
907
8%
3596

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
24%12%47%6%3445%6%26%
75072
Night
23%13%5%7%5%34446%26%
74733
TransparencyDay
59%7%13%15%6%1
74760
Night
59%6%12%15%6%1
74580
SeeingDay
29%10%24%25%11%2
16928
Night
28%10%28%24%8%1
23497

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
15%14%5%9%7%36%5%5%6%25%
1326
11th to 20thDay
15%16%5%7%7%3346%7%27%
1449
21st to endDay
14%15%6%8%7%4345%6%28%
1584
February1st to 10thDay
12%14%48%6%345%5%7%32%
1440
11th to 20thDay
10%17%6%8%7%345%45%32%
1531
21st to endDay
11%15%5%7%5%35%446%36%
1480
March1st to 10thDay
14%12%7%9%6%45%445%30%
1796
11th to 20thDay
14%16%7%9%7%35%447%24%
1849
21st to endDay
17%15%5%6%6%35%45%6%26%
2362
April1st to 10thDay
22%15%6%9%7%35%45%5%20%
2160
11th to 20thDay
19%15%47%5%34446%28%
2258
21st to endDay
20%12%5%8%6%35%447%26%
2412
May1st to 10thDay
25%12%48%6%3445%6%23%
2520
11th to 20thDay
26%11%46%5%35%45%6%25%
2557
21st to endDay
30%10%46%6%3345%6%22%
2918
June1st to 10thDay
32%11%47%7%345%46%19%
2700
11th to 20thDay
32%8%36%5%345%5%7%22%
2864
21st to endDay
31%10%46%5%345%48%20%
2880
July1st to 10thDay
35%11%36%5%245%46%19%
2835
11th to 20thDay
29%12%35%5%24346%26%
2688
21st to endDay
29%10%37%7%35%5%5%7%19%
2745
August1st to 10thDay
24%10%36%6%3346%9%25%
2506
11th to 20thDay
29%11%36%4245%46%26%
2442
21st to endDay
29%8%36%5%3445%8%27%
2525
September1st to 10thDay
29%8%25%42336%7%31%
2160
11th to 20thDay
29%8%36%5%34445%28%
2052
21st to endDay
28%9%25%5%3445%6%30%
1980
October1st to 10thDay
27%10%26%5%24236%33%
1886
11th to 20thDay
27%11%36%5%2435%5%29%
1630
21st to endDay
25%12%45%434346%31%
1782
November1st to 10thDay
25%12%35%5%3344432%
1637
11th to 20thDay
22%15%46%5%2333432%
1348
21st to endDay
25%15%7%6%432235%27%
1330
December1st to 10thDay
19%17%5%8%5%34447%23%
1330
11th to 20thDay
29%13%5%7%433346%22%
1668
21st to endDay
17%15%37%7%3435%6%29%
2442
January1st to 10thNight
14%15%7%9%6%4445%7%25%
2839
11th to 20thNight
16%15%5%8%6%345%5%6%27%
2630
21st to endNight
15%16%5%8%6%245%46%29%
2772
February1st to 10thNight
12%14%5%9%6%345%47%32%
2520
11th to 20thNight
12%14%7%10%6%34445%31%
2314
21st to endNight
11%13%6%8%6%44446%35%
1776
March1st to 10thNight
12%13%6%9%9%445%45%29%
2151
11th to 20thNight
14%17%6%9%6%35%5%45%26%
2110
21st to endNight
17%16%5%8%5%45%45%6%25%
1993
April1st to 10thNight
22%19%6%8%7%3444320%
1800
11th to 20thNight
21%14%47%6%245%45%28%
1652
21st to endNight
24%10%48%5%34346%29%
1544
May1st to 10thNight
24%15%5%7%5%25%445%23%
1440
11th to 20thNight
24%13%36%5%45%45%6%25%
1335
21st to endNight
33%11%35%5%345%46%22%
1356
June1st to 10thNight
33%11%37%7%345%45%20%
1260
11th to 20thNight
33%9%46%435%5%5%7%19%
1109
21st to endNight
34%11%46%5%345%5%5%19%
1080
July1st to 10thNight
35%12%5%6%5%3333421%
1106
11th to 20thNight
35%13%35%43334422%
1268
21st to endNight
32%10%48%6%36%5%46%17%
1573
August1st to 10thNight
27%10%48%7%4445%7%22%
1433
11th to 20thNight
33%10%35%5%34345%24%
1458
21st to endNight
27%8%35%4346%6%7%27%
1829
September1st to 10thNight
29%8%344245%5%6%31%
1800
11th to 20thNight
30%8%345%2335%5%31%
1907
21st to endNight
28%8%36%43445%5%30%
1980
October1st to 10thNight
25%10%26%435%445%30%
2071
11th to 20thNight
26%10%46%5%34446%30%
2330
21st to endNight
27%12%37%5%23446%27%
2574
November1st to 10thNight
27%11%47%5%24345%28%
2436
11th to 20thNight
27%14%37%423346%28%
2831
21st to endNight
25%18%47%5%3343424%
2850
December1st to 10thNight
19%18%7%8%6%34335%23%
2850
11th to 20thNight
27%15%5%6%423448%23%
3531
21st to endNight
17%15%5%8%6%24446%27%
5225

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
59%8%12%14%6%1
1327
11th to 20thDay
55%6%15%17%5%
1449
21st to endDay
58%411%17%9%1
1584
February1st to 10thDay
52%6%11%21%9%2
1440
11th to 20thDay
56%5%11%16%11%1
1538
21st to endDay
50%39%19%17%2
1480
March1st to 10thDay
57%5%11%18%9%1
1800
11th to 20thDay
61%6%8%15%9%1
1849
21st to endDay
59%6%10%14%10%2
2362
April1st to 10thDay
65%7%8%11%8%1
2160
11th to 20thDay
57%6%12%14%10%1
2258
21st to endDay
59%8%10%17%7%
2412
May1st to 10thDay
62%8%11%14%5%
2520
11th to 20thDay
60%7%13%13%7%1
2561
21st to endDay
62%7%14%14%4
2918
June1st to 10thDay
67%7%11%10%5%
2700
11th to 20thDay
61%10%12%14%3
2864
21st to endDay
61%8%13%15%3
2880
July1st to 10thDay
64%8%13%13%2
2757
11th to 20thDay
59%6%15%17%3
2606
21st to endDay
63%10%15%10%2
2592
August1st to 10thDay
55%9%20%12%4
2492
11th to 20thDay
59%8%14%16%3
2442
21st to endDay
56%8%18%15%3
2525
September1st to 10thDay
52%7%14%18%8%
2160
11th to 20thDay
58%6%14%15%6%1
2052
21st to endDay
55%7%14%16%7%
1980
October1st to 10thDay
55%5%13%18%8%
1886
11th to 20thDay
57%7%17%14%5%
1630
21st to endDay
57%5%13%17%6%1
1782
November1st to 10thDay
55%5%14%15%8%1
1637
11th to 20thDay
58%414%17%7%
1348
21st to endDay
61%6%12%14%8%
1330
December1st to 10thDay
62%6%11%15%6%
1330
11th to 20thDay
62%6%13%13%6%1
1667
21st to endDay
53%6%13%18%10%
2442
January1st to 10thNight
60%5%12%16%5%2
2839
11th to 20thNight
57%6%13%17%6%1
2630
21st to endNight
57%5%10%17%10%1
2772
February1st to 10thNight
53%411%20%9%2
2520
11th to 20thNight
57%413%16%9%1
2318
21st to endNight
51%411%20%12%1
1776
March1st to 10thNight
56%7%10%15%10%2
2160
11th to 20thNight
59%5%10%14%12%
2111
21st to endNight
60%6%10%15%8%1
1993
April1st to 10thNight
68%5%8%11%7%1
1800
11th to 20thNight
57%5%12%16%9%1
1652
21st to endNight
59%6%12%13%8%2
1544
May1st to 10thNight
63%7%11%14%41
1440
11th to 20thNight
59%9%11%16%5%
1336
21st to endNight
63%7%10%15%5%
1357
June1st to 10thNight
67%8%10%10%5%1
1260
11th to 20thNight
64%9%15%9%3
1109
21st to endNight
66%7%12%12%3
1080
July1st to 10thNight
67%7%11%12%3
1075
11th to 20thNight
65%6%12%13%4
1226
21st to endNight
68%8%12%11%1
1486
August1st to 10thNight
62%8%17%11%2
1422
11th to 20thNight
63%7%12%14%3
1458
21st to endNight
56%9%15%16%4
1829
September1st to 10thNight
54%7%16%17%7%
1800
11th to 20thNight
55%7%16%17%6%
1907
21st to endNight
55%6%15%16%7%1
1980
October1st to 10thNight
57%6%12%16%9%
2071
11th to 20thNight
56%7%12%19%6%
2330
21st to endNight
61%5%11%16%7%1
2574
November1st to 10thNight
59%6%11%17%7%1
2436
11th to 20thNight
59%6%13%16%5%
2831
21st to endNight
64%5%11%13%6%
2850
December1st to 10thNight
66%6%12%11%5%1
2850
11th to 20thNight
61%6%13%16%41
3533
21st to endNight
56%6%12%19%6%
5225

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
20%13%32%22%11%2
370
11th to 20thDay
24%11%35%20%8%3
356
21st to endDay
21%13%29%29%8%1
374
February1st to 10thDay
20%10%29%30%9%2
340
11th to 20thDay
16%15%35%26%7%1
336
21st to endDay
18%13%33%25%9%3
280
March1st to 10thDay
16%13%34%26%8%3
340
11th to 20thDay
22%13%24%23%15%4
340
21st to endDay
22%12%28%28%8%2
456
April1st to 10thDay
25%14%26%24%10%2
420
11th to 20thDay
23%11%23%26%13%4
536
21st to endDay
25%9%26%25%13%4
600
May1st to 10thDay
29%9%24%25%10%3
603
11th to 20thDay
28%8%22%22%14%5%
624
21st to endDay
34%7%21%28%9%1
680
June1st to 10thDay
35%8%19%22%12%4
630
11th to 20thDay
35%8%17%27%11%2
630
21st to endDay
37%7%15%25%11%5%
630
July1st to 10thDay
38%7%19%18%15%3
620
11th to 20thDay
32%7%18%26%16%1
618
21st to endDay
34%5%15%30%14%2
685
August1st to 10thDay
31%6%16%28%16%3
625
11th to 20thDay
32%8%18%27%14%3
617
21st to endDay
29%7%21%27%12%4
644
September1st to 10thDay
32%10%24%20%12%2
450
11th to 20thDay
29%10%27%27%7%1
396
21st to endDay
32%11%26%24%6%1
360
October1st to 10thDay
29%10%34%21%5%1
360
11th to 20thDay
30%10%20%29%10%
360
21st to endDay
28%16%21%22%12%1
396
November1st to 10thDay
31%18%31%16%31
365
11th to 20thDay
29%14%26%20%11%
370
21st to endDay
31%17%27%19%6%
370
December1st to 10thDay
29%11%28%25%7%1
370
11th to 20thDay
25%17%33%20%5%1
370
21st to endDay
22%15%28%24%8%3
407
January1st to 10thNight
21%16%34%20%7%1
850
11th to 20thNight
22%14%35%23%5%
829
21st to endNight
23%12%32%27%5%
880
February1st to 10thNight
20%11%35%26%7%1
800
11th to 20thNight
19%12%37%26%6%1
740
21st to endNight
18%7%34%28%11%3
592
March1st to 10thNight
16%13%35%25%9%1
720
11th to 20thNight
23%10%27%29%10%1
671
21st to endNight
24%11%32%24%7%1
594
April1st to 10thNight
29%11%28%22%9%1
540
11th to 20thNight
27%10%28%23%12%1
534
21st to endNight
29%7%23%30%10%1
540
May1st to 10thNight
30%7%22%27%11%3
540
11th to 20thNight
30%8%24%25%11%2
532
21st to endNight
37%6%21%26%9%1
583
June1st to 10thNight
37%5%20%26%11%1
540
11th to 20thNight
35%6%19%29%11%1
389
21st to endNight
37%6%15%24%15%3
360
July1st to 10thNight
41%7%17%24%11%1
375
11th to 20thNight
39%6%16%28%11%
522
21st to endNight
34%5%16%33%11%1
590
August1st to 10thNight
31%7%17%31%14%1
538
11th to 20thNight
34%8%16%26%14%2
532
21st to endNight
31%421%26%16%1
594
September1st to 10thNight
30%10%25%26%9%1
540
11th to 20thNight
32%9%31%20%7%
540
21st to endNight
34%8%30%22%5%
540
October1st to 10thNight
29%10%31%25%5%1
631
11th to 20thNight
31%8%24%27%9%1
805
21st to endNight
32%12%25%23%8%1
891
November1st to 10thNight
32%14%31%17%41
830
11th to 20thNight
32%13%27%19%7%1
850
21st to endNight
32%16%32%16%3
850
December1st to 10thNight
29%12%32%22%6%1
850
11th to 20thNight
27%17%31%21%4
850
21st to endNight
22%14%32%23%8%1
935
Page generated at 2024-01-13 09:37:54. Version ac07

Copyright 2024 Attilla Danko


Blanc-Sablon Clear Sky Chart |Charts Home