Shediac
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Shediac clear sky chart from 2005-11-06 to 2025-01-07.

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
22%
24604
12%
104085
5%
24227
31%
24227
12%
71641

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
11%
870
16%
4752
2%
848
22%
848
7%
2850
January11th to 20thNight
16%
832
15%
4483
3%
808
27%
808
7%
2994
January21st to endNight
19%
831
11%
4493
6%
814
34%
814
9%
2992
February1st to 10thNight
15%
760
13%
2470
4%
760
27%
760
13%
1789
February11th to 20thNight
13%
743
12%
2406
2%
740
26%
740
11%
1769
February21st to endNight
20%
628
15%
2036
4%
628
33%
628
15%
1426
March1st to 10thNight
15%
756
13%
3408
5%
743
25%
743
9%
2653
March11th to 20thNight
19%
758
9%
3480
5%
740
28%
740
8%
2764
March21st to endNight
18%
835
10%
3766
5%
814
27%
814
9%
2907
April1st to 10thNight
19%
591
12%
1921
6%
591
26%
591
12%
1450
April11th to 20thNight
21%
564
15%
1743
6%
564
30%
564
17%
1247
April21st to endNight
22%
570
13%
1710
5%
570
30%
570
16%
1246
May1st to 10thNight
25%
569
10%
2704
7%
566
32%
566
10%
2002
May11th to 20thNight
27%
555
13%
2460
5%
552
35%
552
14%
1449
May21st to endNight
23%
615
7%
2737
4%
604
30%
604
13%
1875
June1st to 10thNight
30%
446
9%
1396
6%
446
33%
446
17%
1019
June11th to 20thNight
30%
380
11%
1330
7%
380
36%
380
17%
909
June21st to endNight
28%
380
7%
1330
4%
380
32%
380
13%
981
July1st to 10thNight
32%
368
11%
2089
7%
360
40%
360
12%
1372
July11th to 20thNight
37%
393
8%
2062
8%
386
42%
386
13%
1354
July21st to endNight
37%
621
8%
2406
8%
580
40%
580
15%
1560
August1st to 10thNight
39%
566
8%
2715
7%
553
43%
553
12%
1987
August11th to 20thNight
38%
559
11%
2577
7%
551
43%
551
14%
1636
August21st to endNight
41%
625
15%
2958
9%
616
48%
616
19%
1633
September1st to 10thNight
32%
570
18%
1900
9%
570
43%
570
25%
1166
September11th to 20thNight
39%
665
19%
1995
13%
665
45%
665
27%
1262
September21st to endNight
33%
760
20%
2133
10%
760
42%
760
25%
1400
October1st to 10thNight
31%
760
12%
3312
8%
740
39%
740
13%
2440
October11th to 20thNight
24%
760
15%
2801
7%
740
34%
740
16%
1967
October21st to endNight
17%
836
11%
3301
5%
814
27%
814
10%
2351
November1st to 10thNight
17%
875
14%
2723
4%
875
27%
875
14%
1942
November11th to 20thNight
16%
900
15%
2800
5%
900
26%
900
13%
2034
November21st to endNight
15%
900
12%
2800
3%
900
25%
900
12%
2068
December1st to 10thNight
14%
891
20%
4409
1%
870
25%
870
9%
2665
December11th to 20thNight
10%
897
8%
5136
2%
869
21%
869
6%
3356
December21st to endNight
13%
975
10%
7343
2%
930
25%
930
4%
5126

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
18%10%38%5%4445%7%32%
105152
Night
18%11%38%5%4435%6%33%
103983
TransparencyDay
52%5%12%21%9%1
108715
Night
52%412%21%10%1
108509
SeeingDay
23%16%32%21%6%1
17033
Night
24%15%33%22%6%
24682

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%13%5%10%6%45%34430%
2249
11th to 20thDay
13%15%310%5%44345%35%
2381
21st to endDay
12%11%49%7%5%435%6%33%
3124
February1st to 10thDay
17%12%49%5%4445%5%31%
1710
11th to 20thDay
16%13%5%10%5%5%5%446%28%
1663
21st to endDay
11%13%5%8%5%4436%7%34%
1416
March1st to 10thDay
22%15%5%8%5%34345%26%
3416
11th to 20thDay
14%19%5%12%5%5%5%35%5%21%
3480
21st to endDay
27%15%5%8%43345%5%21%
3816
April1st to 10thDay
21%13%49%6%5%435%5%27%
2258
11th to 20thDay
21%11%46%44435%6%31%
2385
21st to endDay
23%11%47%44435%7%29%
2470
May1st to 10thDay
23%17%37%5%43345%26%
4234
11th to 20thDay
17%9%27%44445%7%37%
4398
21st to endDay
16%9%38%6%6%5%47%8%28%
4836
June1st to 10thDay
26%9%36%5%4435%7%26%
2799
11th to 20thDay
20%7%37%5%45%36%8%32%
2850
21st to endDay
25%9%37%5%4435%6%29%
2850
July1st to 10thDay
14%8%37%6%6%6%5%6%8%31%
4760
11th to 20thDay
15%6%37%5%5%6%47%9%34%
4669
21st to endDay
12%7%27%5%5%5%5%6%9%37%
4728
August1st to 10thDay
17%9%38%5%5%6%46%7%30%
4105
11th to 20thDay
14%6%36%45%6%5%7%9%36%
4045
21st to endDay
13%5%25%44446%8%44%
4419
September1st to 10thDay
16%5%26%5%45%35%8%43%
2280
11th to 20thDay
17%7%36%44425%5%42%
2181
21st to endDay
18%6%25%444445%43%
2047
October1st to 10thDay
18%8%36%33445%7%40%
1900
11th to 20thDay
19%9%37%44445%6%36%
1900
21st to endDay
20%9%37%5%6%435%6%33%
2062
November1st to 10thDay
19%11%48%5%5%4346%32%
1575
11th to 20thDay
20%14%46%445%436%30%
1600
21st to endDay
19%15%37%5%4336%5%29%
1600
December1st to 10thDay
17%12%47%44335%7%33%
2610
11th to 20thDay
18%16%48%44323435%
2860
21st to endDay
16%12%5%14%5%4424430%
3476
January1st to 10thNight
14%12%48%44435%6%36%
4839
11th to 20thNight
16%11%5%9%6%44445%33%
4584
21st to endNight
14%14%5%8%8%3325%6%32%
4532
February1st to 10thNight
16%13%48%5%45%36%5%30%
2470
11th to 20thNight
17%14%310%6%45%36%5%28%
2403
21st to endNight
13%15%48%6%4335%5%34%
2036
March1st to 10thNight
24%14%411%6%5%433423%
3424
11th to 20thNight
21%18%410%5%5%5%34421%
3479
21st to endNight
29%12%38%5%4445%324%
3816
April1st to 10thNight
23%12%5%8%5%5%434427%
1921
11th to 20thNight
22%11%28%443347%31%
1743
21st to endNight
21%13%39%444236%32%
1710
May1st to 10thNight
26%14%37%44446%6%24%
2710
11th to 20thNight
17%9%26%44335%8%40%
2506
21st to endNight
14%10%48%5%5%6%5%6%6%31%
2749
June1st to 10thNight
26%9%26%44446%6%29%
1396
11th to 20thNight
20%8%37%5%5%4347%34%
1330
21st to endNight
24%10%47%5%45%5%5%5%28%
1330
July1st to 10thNight
14%8%38%6%5%5%6%7%7%31%
2210
11th to 20thNight
12%8%37%5%6%6%5%6%8%34%
2264
21st to endNight
12%6%36%5%5%5%46%8%40%
2830
August1st to 10thNight
17%7%410%6%6%5%47%7%28%
2825
11th to 20thNight
10%7%27%6%5%6%47%8%36%
2782
21st to endNight
14%5%25%44445%8%48%
3236
September1st to 10thNight
16%6%16%434348%45%
1900
11th to 20thNight
16%7%25%433346%46%
1995
21st to endNight
15%6%27%44436%5%44%
2133
October1st to 10thNight
18%8%27%444446%40%
2280
11th to 20thNight
17%9%37%44335%6%40%
2280
21st to endNight
23%9%37%5%44345%34%
2532
November1st to 10thNight
20%10%36%5%5%445%5%34%
2723
11th to 20thNight
21%12%37%6%4335%6%31%
2800
21st to endNight
23%13%36%444345%31%
2800
December1st to 10thNight
15%9%37%5%45%35%6%38%
4580
11th to 20thNight
18%15%47%33324437%
5333
21st to endNight
20%14%5%12%433345%28%
7502

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
57%413%18%7%1
2250
11th to 20thDay
52%6%6%19%15%1
2381
21st to endDay
52%5%13%15%14%1
3124
February1st to 10thDay
56%411%16%11%2
1710
11th to 20thDay
58%6%8%17%9%1
1671
21st to endDay
50%412%20%12%3
1416
March1st to 10thDay
60%6%9%19%6%2
3420
11th to 20thDay
63%6%10%15%5%1
3480
21st to endDay
64%5%6%17%7%2
3816
April1st to 10thDay
60%5%7%16%10%3
2258
11th to 20thDay
52%6%8%20%11%1
2385
21st to endDay
55%5%9%16%11%3
2470
May1st to 10thDay
60%6%8%18%7%1
4248
11th to 20thDay
46%6%15%25%7%
4402
21st to endDay
51%9%13%18%9%
4836
June1st to 10thDay
57%5%12%19%7%
2799
11th to 20thDay
50%6%12%22%9%1
2850
21st to endDay
57%6%11%16%9%1
2850
July1st to 10thDay
50%5%17%18%10%1
4685
11th to 20thDay
46%6%16%25%7%
4588
21st to endDay
43%7%18%26%6%
4577
August1st to 10thDay
54%5%11%24%6%
4092
11th to 20thDay
44%6%14%25%11%
4084
21st to endDay
38%415%26%16%
4419
September1st to 10thDay
39%6%16%26%13%
2280
11th to 20thDay
44%412%25%13%1
2181
21st to endDay
43%411%27%15%1
2047
October1st to 10thDay
46%412%28%9%
3160
11th to 20thDay
46%49%31%10%1
3140
21st to endDay
44%315%21%17%
3376
November1st to 10thDay
56%411%21%8%1
1575
11th to 20thDay
57%5%13%15%10%1
1600
21st to endDay
57%6%14%18%6%
1600
December1st to 10thDay
53%413%24%6%
2610
11th to 20thDay
56%310%19%10%2
2859
21st to endDay
60%313%17%7%1
3476
January1st to 10thNight
49%416%26%5%1
4839
11th to 20thNight
53%6%9%22%9%1
4584
21st to endNight
54%411%21%9%1
4532
February1st to 10thNight
56%411%16%11%2
2470
11th to 20thNight
58%49%16%11%1
2406
21st to endNight
53%49%20%13%2
2036
March1st to 10thNight
66%46%16%7%2
3433
11th to 20thNight
66%5%7%14%7%1
3480
21st to endNight
64%45%17%9%1
3816
April1st to 10thNight
60%48%14%10%3
1921
11th to 20thNight
53%5%9%20%12%1
1743
21st to endNight
56%310%15%14%2
1710
May1st to 10thNight
59%6%12%15%7%1
2716
11th to 20thNight
44%418%25%7%1
2507
21st to endNight
50%8%19%16%7%
2750
June1st to 10thNight
54%6%13%19%8%
1396
11th to 20thNight
50%6%10%23%9%1
1330
21st to endNight
57%6%12%16%8%1
1330
July1st to 10thNight
49%5%15%20%10%
2175
11th to 20thNight
47%6%19%21%8%
2222
21st to endNight
41%6%17%24%11%
2741
August1st to 10thNight
55%7%13%20%5%
2813
11th to 20thNight
44%5%17%22%11%
2809
21st to endNight
36%417%27%15%1
3235
September1st to 10thNight
40%5%13%29%13%
1900
11th to 20thNight
39%5%14%28%13%1
1995
21st to endNight
42%5%12%27%13%1
2133
October1st to 10thNight
51%410%27%8%
3800
11th to 20thNight
38%411%33%13%
3779
21st to endNight
45%314%23%14%
4168
November1st to 10thNight
53%5%13%20%9%1
2723
11th to 20thNight
56%413%17%10%1
2800
21st to endNight
56%5%14%18%7%
2800
December1st to 10thNight
48%314%25%9%
4580
11th to 20thNight
53%310%21%11%2
5335
21st to endNight
62%211%16%8%1
7502

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%22%33%13%1
192
11th to 20thDay
28%23%31%15%3
260
21st to endDay
18%17%40%22%4
407
February1st to 10thDay
26%20%34%16%4
370
11th to 20thDay
23%27%32%15%31
366
21st to endDay
18%22%39%16%5%
310
March1st to 10thDay
25%22%36%14%21
460
11th to 20thDay
20%25%33%18%4
460
21st to endDay
30%20%32%13%41
506
April1st to 10thDay
29%24%32%12%2
460
11th to 20thDay
26%22%31%17%4
452
21st to endDay
28%17%30%19%5%
460
May1st to 10thDay
31%16%31%18%5%
539
11th to 20thDay
23%14%31%23%8%1
674
21st to endDay
23%16%35%21%4
735
June1st to 10thDay
32%11%31%20%6%
680
11th to 20thDay
22%12%33%25%6%1
680
21st to endDay
26%10%29%27%7%1
680
July1st to 10thDay
21%10%35%26%8%1
670
11th to 20thDay
16%7%33%32%10%1
668
21st to endDay
18%7%32%32%10%1
689
August1st to 10thDay
16%8%30%35%9%1
486
11th to 20thDay
18%9%29%31%12%2
479
21st to endDay
14%13%28%32%11%2
539
September1st to 10thDay
13%10%40%26%9%2
490
11th to 20thDay
21%14%29%24%11%1
490
21st to endDay
19%15%31%25%7%2
467
October1st to 10thDay
19%14%31%21%13%1
390
11th to 20thDay
24%18%30%19%8%1
390
21st to endDay
24%22%31%17%41
429
November1st to 10thDay
26%22%30%15%7%
395
11th to 20thDay
31%21%30%13%41
400
21st to endDay
30%24%31%13%3
400
December1st to 10thDay
30%19%34%14%3
400
11th to 20thDay
32%29%26%12%1
340
21st to endDay
22%27%36%14%1
220
January1st to 10thNight
25%20%34%16%4
881
11th to 20thNight
24%20%33%18%5%
837
21st to endNight
18%19%37%20%6%
836
February1st to 10thNight
25%16%37%18%4
760
11th to 20thNight
26%22%34%16%21
743
21st to endNight
21%17%36%22%41
628
March1st to 10thNight
24%16%37%20%2
760
11th to 20thNight
25%17%31%21%6%1
760
21st to endNight
28%15%31%20%6%
836
April1st to 10thNight
30%16%29%22%3
591
11th to 20thNight
27%14%32%20%6%
564
21st to endNight
29%15%30%19%7%1
570
May1st to 10thNight
30%11%29%22%7%1
570
11th to 20thNight
25%10%31%25%8%1
562
21st to endNight
19%11%41%25%4
616
June1st to 10thNight
29%7%30%29%6%
446
11th to 20thNight
23%7%33%31%6%1
380
21st to endNight
26%7%31%28%8%1
380
July1st to 10thNight
18%6%38%28%10%
370
11th to 20thNight
15%8%33%33%11%1
396
21st to endNight
16%6%32%38%8%
623
August1st to 10thNight
16%433%35%10%1
568
11th to 20thNight
18%6%30%32%13%1
562
21st to endNight
15%6%30%35%12%1
627
September1st to 10thNight
18%8%38%28%7%
570
11th to 20thNight
19%9%28%34%9%1
665
21st to endNight
19%10%33%28%9%
760
October1st to 10thNight
21%10%32%26%10%
760
11th to 20thNight
21%15%36%20%8%
760
21st to endNight
29%21%29%18%3
836
November1st to 10thNight
28%19%32%17%5%
875
11th to 20thNight
28%20%30%16%5%1
900
21st to endNight
30%22%30%15%3
900
December1st to 10thNight
30%17%33%17%3
900
11th to 20thNight
31%22%33%12%2
900
21st to endNight
29%21%28%19%31
990
Page generated at 2025-01-04 04:24:01. Version ac07

Copyright © 2025 Attilla Danko.


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