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 2024-01-22.

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
23%
23420
13%
74848
5%
23353
32%
23353
15%
53345

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
12%
850
12%
2838
2%
847
23%
847
10%
2080
January11th to 20thNight
16%
837
12%
2739
3%
837
27%
837
11%
2039
January21st to endNight
20%
800
18%
2598
6%
800
35%
800
17%
1751
February1st to 10thNight
14%
720
13%
2340
4%
720
26%
720
14%
1676
February11th to 20thNight
14%
703
12%
2276
2%
700
26%
700
11%
1678
February21st to endNight
19%
592
16%
1920
4%
592
34%
592
15%
1353
March1st to 10thNight
16%
719
16%
1994
5%
719
26%
719
15%
1520
March11th to 20thNight
20%
720
15%
1980
5%
720
28%
720
15%
1470
March21st to endNight
19%
792
15%
2178
5%
792
28%
792
16%
1641
April1st to 10thNight
18%
560
11%
1820
5%
560
25%
560
11%
1385
April11th to 20thNight
21%
534
16%
1651
6%
534
30%
534
17%
1179
April21st to endNight
23%
540
13%
1620
5%
540
30%
540
15%
1198
May1st to 10thNight
26%
540
14%
1548
7%
540
32%
540
16%
1158
May11th to 20thNight
27%
532
14%
1417
5%
532
35%
532
20%
1020
May21st to endNight
24%
583
11%
1551
4%
582
31%
582
22%
1120
June1st to 10thNight
29%
423
9%
1323
6%
423
33%
423
17%
966
June11th to 20thNight
31%
360
12%
1260
7%
360
38%
360
16%
871
June21st to endNight
29%
360
7%
1260
4%
360
33%
360
14%
924
July1st to 10thNight
33%
350
12%
1225
7%
350
41%
350
20%
800
July11th to 20thNight
38%
374
11%
1244
8%
374
43%
374
20%
830
July21st to endNight
37%
590
11%
1528
8%
558
40%
558
20%
1125
August1st to 10thNight
41%
538
11%
1600
7%
534
44%
534
23%
1083
August11th to 20thNight
39%
532
13%
1596
7%
532
43%
532
20%
1112
August21st to endNight
42%
594
16%
1838
10%
594
48%
594
27%
1161
September1st to 10thNight
32%
540
16%
1800
9%
540
42%
540
25%
1111
September11th to 20thNight
38%
630
19%
1890
14%
630
45%
630
25%
1211
September21st to endNight
32%
720
21%
2020
10%
720
42%
720
26%
1316
October1st to 10thNight
31%
720
18%
2160
8%
720
39%
720
22%
1440
October11th to 20thNight
25%
720
19%
2160
7%
720
35%
720
21%
1454
October21st to endNight
18%
792
15%
2398
5%
792
27%
792
13%
1753
November1st to 10thNight
18%
825
14%
2583
4%
825
27%
825
14%
1846
November11th to 20thNight
17%
850
16%
2660
5%
850
28%
850
13%
1909
November21st to endNight
16%
850
12%
2660
3%
850
26%
850
12%
1943
December1st to 10thNight
14%
850
11%
2660
1%
850
25%
850
12%
1977
December11th to 20thNight
10%
850
11%
3319
2%
849
21%
849
8%
2537
December21st to endNight
13%
930
7%
5194
2%
907
24%
907
5%
3708

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%9%47%6%35%45%6%32%
74820
Night
19%11%47%5%3445%6%33%
75105
TransparencyDay
52%5%12%20%9%1
74516
Night
53%5%12%20%9%1
74944
SeeingDay
23%16%32%22%6%1
15706
Night
24%15%32%22%6%
23426

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
18%16%5%8%6%34445%29%
1327
11th to 20thDay
18%15%5%10%6%34345%27%
1437
21st to endDay
11%10%47%6%35%5%46%38%
1792
February1st to 10thDay
17%11%5%8%5%45%45%5%32%
1620
11th to 20thDay
18%12%5%8%6%45%5%46%28%
1573
21st to endDay
11%12%6%7%5%45%35%8%34%
1334
March1st to 10thDay
17%15%6%9%6%3445%5%27%
1962
11th to 20thDay
14%11%6%10%6%4445%6%30%
1980
21st to endDay
19%14%6%7%6%24435%30%
2178
April1st to 10thDay
21%12%5%8%7%45%445%26%
2139
11th to 20thDay
21%10%45%5%3445%7%31%
2258
21st to endDay
24%11%47%5%34447%28%
2340
May1st to 10thDay
25%10%46%6%35%5%45%28%
2412
11th to 20thDay
23%9%35%5%34446%35%
2478
21st to endDay
20%8%36%5%35%45%8%33%
2724
June1st to 10thDay
27%8%36%6%35%45%7%27%
2651
11th to 20thDay
21%7%36%6%36%45%8%32%
2700
21st to endDay
25%8%46%6%35%446%29%
2700
July1st to 10thDay
17%6%35%5%36%6%5%9%35%
2700
11th to 20thDay
14%5%36%6%46%6%7%10%33%
2651
21st to endDay
17%7%36%7%46%6%6%8%30%
2697
August1st to 10thDay
17%6%346%35%6%6%8%35%
2327
11th to 20thDay
16%6%36%6%45%6%7%9%32%
2304
21st to endDay
14%5%35%5%345%5%7%42%
2517
September1st to 10thDay
16%425%5%35%45%8%43%
2160
11th to 20thDay
18%7%35%5%3445%5%41%
2067
21st to endDay
18%6%34434445%45%
1940
October1st to 10thDay
18%7%35%4245%5%7%41%
1800
11th to 20thDay
19%9%36%5%445%47%35%
1800
21st to endDay
21%8%36%6%45%45%6%32%
1954
November1st to 10thDay
19%10%47%6%345%46%32%
1495
11th to 20thDay
18%12%46%435%5%46%32%
1520
21st to endDay
17%14%46%6%3446%6%30%
1520
December1st to 10thDay
23%13%48%5%33345%30%
1520
11th to 20thDay
18%18%5%8%5%4433428%
1812
21st to endDay
19%11%5%12%7%33435%28%
2431
January1st to 10thNight
18%13%6%8%6%44445%29%
2838
11th to 20thNight
17%12%5%9%7%34445%30%
2739
21st to endNight
12%12%5%7%6%3435%6%36%
2598
February1st to 10thNight
16%12%47%6%35%45%6%31%
2340
11th to 20thNight
18%13%48%7%35%45%5%27%
2273
21st to endNight
13%13%5%7%7%3445%5%33%
1920
March1st to 10thNight
17%16%48%7%34445%29%
1985
11th to 20thNight
17%11%49%6%35%5%5%5%31%
1979
21st to endNight
20%13%5%7%6%2433432%
2178
April1st to 10thNight
24%11%5%7%5%44445%26%
1820
11th to 20thNight
22%10%36%6%33447%32%
1651
21st to endNight
22%12%38%5%34335%31%
1620
May1st to 10thNight
24%10%35%5%25%5%5%6%29%
1548
11th to 20thNight
23%9%26%5%34346%34%
1416
21st to endNight
16%9%36%446%6%47%35%
1550
June1st to 10thNight
26%8%35%4445%6%7%29%
1323
11th to 20thNight
22%7%36%6%44347%35%
1260
21st to endNight
24%9%5%6%5%35%5%5%5%29%
1260
July1st to 10thNight
17%8%26%4347%6%9%35%
1260
11th to 20thNight
12%7%36%6%46%6%6%8%34%
1286
21st to endNight
15%8%47%7%46%5%5%7%31%
1617
August1st to 10thNight
14%6%36%6%36%5%6%7%38%
1612
11th to 20thNight
16%8%36%7%35%5%5%7%35%
1596
21st to endNight
14%5%25%5%345%5%8%41%
1838
September1st to 10thNight
17%6%25%5%34448%44%
1800
11th to 20thNight
16%7%34424346%45%
1890
21st to endNight
16%5%26%5%2445%5%45%
2020
October1st to 10thNight
18%7%26%5%33446%40%
2160
11th to 20thNight
18%8%36%5%2445%6%39%
2160
21st to endNight
24%9%36%6%34445%32%
2398
November1st to 10thNight
21%10%36%5%35%45%6%33%
2583
11th to 20thNight
19%10%36%6%3445%6%32%
2660
21st to endNight
21%12%36%5%35%346%32%
2660
December1st to 10thNight
24%11%46%5%35%446%28%
2660
11th to 20thNight
21%18%5%7%43333428%
3371
21st to endNight
23%14%5%9%423335%28%
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
59%411%14%10%1
1328
11th to 20thDay
62%5%8%14%10%1
1437
21st to endDay
48%5%11%18%17%1
1792
February1st to 10thDay
55%411%17%11%2
1620
11th to 20thDay
59%6%8%17%9%1
1581
21st to endDay
49%412%21%12%2
1334
March1st to 10thDay
59%5%8%19%8%1
1966
11th to 20thDay
56%410%20%8%3
1980
21st to endDay
58%49%18%9%3
2178
April1st to 10thDay
61%5%7%15%10%3
2139
11th to 20thDay
52%6%9%20%12%2
2258
21st to endDay
57%5%9%16%10%3
2340
May1st to 10thDay
60%6%7%16%10%1
2412
11th to 20thDay
51%5%8%24%11%1
2482
21st to endDay
50%6%13%22%8%1
2724
June1st to 10thDay
57%5%12%18%7%
2651
11th to 20thDay
51%6%11%22%9%1
2700
21st to endDay
56%6%12%16%9%1
2700
July1st to 10thDay
44%7%17%22%9%1
2625
11th to 20thDay
43%8%17%23%8%1
2570
21st to endDay
50%8%13%21%7%
2546
August1st to 10thDay
46%7%14%26%7%
2314
11th to 20thDay
46%9%17%22%6%
2304
21st to endDay
40%6%15%27%12%
2517
September1st to 10thDay
39%6%16%25%13%
2160
11th to 20thDay
45%411%25%13%1
2067
21st to endDay
42%411%27%15%1
1940
October1st to 10thDay
44%5%12%28%10%1
1800
11th to 20thDay
50%5%12%25%7%1
1800
21st to endDay
55%412%18%10%
1954
November1st to 10thDay
55%411%20%9%1
1495
11th to 20thDay
54%5%14%15%11%1
1520
21st to endDay
55%6%14%18%6%
1520
December1st to 10thDay
59%6%14%15%6%
1520
11th to 20thDay
63%310%16%7%1
1811
21st to endDay
61%316%13%6%1
2431
January1st to 10thNight
58%411%18%8%1
2838
11th to 20thNight
57%6%11%16%8%1
2739
21st to endNight
49%412%22%11%2
2598
February1st to 10thNight
55%411%17%11%2
2340
11th to 20thNight
58%410%16%11%1
2276
21st to endNight
53%49%19%13%2
1920
March1st to 10thNight
58%48%18%10%2
1994
11th to 20thNight
56%48%19%11%2
1980
21st to endNight
57%47%18%11%2
2178
April1st to 10thNight
61%48%13%10%3
1820
11th to 20thNight
53%410%20%12%1
1651
21st to endNight
58%310%15%13%1
1620
May1st to 10thNight
55%5%8%18%11%2
1548
11th to 20thNight
52%411%22%11%1
1417
21st to endNight
47%8%15%20%10%1
1551
June1st to 10thNight
54%6%13%18%8%
1323
11th to 20thNight
51%6%9%23%9%1
1260
21st to endNight
56%7%12%16%9%1
1260
July1st to 10thNight
44%8%17%25%7%
1225
11th to 20thNight
45%8%16%22%10%
1244
21st to endNight
50%7%16%19%7%
1528
August1st to 10thNight
44%8%15%26%7%
1600
11th to 20thNight
48%6%17%22%6%
1596
21st to endNight
39%7%18%27%9%
1838
September1st to 10thNight
40%5%13%30%12%
1800
11th to 20thNight
40%5%14%27%13%1
1890
21st to endNight
41%5%12%27%14%1
2020
October1st to 10thNight
45%5%11%27%11%
2160
11th to 20thNight
47%414%27%7%
2160
21st to endNight
55%5%11%20%10%1
2398
November1st to 10thNight
53%5%13%19%9%1
2583
11th to 20thNight
54%5%13%18%10%1
2660
21st to endNight
54%6%14%19%7%
2660
December1st to 10thNight
58%416%16%6%
2660
11th to 20thNight
62%49%18%7%
3373
21st to endNight
62%313%15%6%1
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
29%22%34%14%1
180
11th to 20thDay
28%24%31%14%3
260
21st to endDay
17%16%41%21%3
378
February1st to 10thDay
25%20%36%16%3
340
11th to 20thDay
24%25%32%15%31
336
21st to endDay
16%23%39%17%5%
282
March1st to 10thDay
24%22%37%14%21
420
11th to 20thDay
19%25%35%17%4
420
21st to endDay
28%20%33%14%42
462
April1st to 10thDay
29%24%32%12%2
420
11th to 20thDay
26%21%31%17%4
412
21st to endDay
29%17%30%19%5%
420
May1st to 10thDay
31%15%31%18%5%
495
11th to 20thDay
25%15%30%22%7%1
624
21st to endDay
24%15%33%22%5%
680
June1st to 10thDay
32%10%32%19%7%
630
11th to 20thDay
23%11%32%26%6%1
630
21st to endDay
25%8%29%29%8%1
630
July1st to 10thDay
21%9%34%27%8%1
620
11th to 20thDay
15%7%32%34%11%1
618
21st to endDay
19%6%31%34%11%
637
August1st to 10thDay
15%7%29%37%10%1
446
11th to 20thDay
19%8%28%31%13%2
439
21st to endDay
14%13%27%33%10%2
495
September1st to 10thDay
12%9%40%28%9%2
450
11th to 20thDay
23%15%28%23%10%1
450
21st to endDay
19%15%32%24%7%3
430
October1st to 10thDay
19%15%30%21%14%1
360
11th to 20thDay
23%18%29%21%9%1
360
21st to endDay
24%22%30%18%5%1
396
November1st to 10thDay
25%22%29%16%7%
365
11th to 20thDay
27%21%32%14%41
370
21st to endDay
28%24%32%13%3
370
December1st to 10thDay
30%19%33%15%3
370
11th to 20thDay
31%30%27%11%1
313
21st to endDay
23%29%34%14%1
198
January1st to 10thNight
25%20%34%17%4
850
11th to 20thNight
24%20%33%18%5%
837
21st to endNight
18%19%36%21%6%1
800
February1st to 10thNight
24%16%38%17%4
720
11th to 20thNight
27%21%34%16%31
703
21st to endNight
20%17%36%22%41
592
March1st to 10thNight
24%16%38%20%2
720
11th to 20thNight
24%16%31%22%6%1
720
21st to endNight
26%15%31%21%6%1
792
April1st to 10thNight
31%16%29%21%3
560
11th to 20thNight
28%14%32%20%6%
534
21st to endNight
29%14%29%20%7%1
540
May1st to 10thNight
30%11%29%23%7%1
540
11th to 20thNight
26%11%31%24%7%1
532
21st to endNight
20%11%40%25%4
583
June1st to 10thNight
29%6%30%29%6%
423
11th to 20thNight
24%7%31%32%7%1
360
21st to endNight
25%7%31%28%8%1
360
July1st to 10thNight
18%5%38%29%10%
350
11th to 20thNight
15%8%32%33%11%1
374
21st to endNight
16%6%32%38%8%1
590
August1st to 10thNight
16%432%36%11%1
538
11th to 20thNight
19%6%29%33%13%1
532
21st to endNight
15%6%29%36%12%1
594
September1st to 10thNight
19%7%37%29%8%
540
11th to 20thNight
20%10%27%33%10%1
630
21st to endNight
19%10%34%27%9%
720
October1st to 10thNight
22%10%32%26%10%
720
11th to 20thNight
20%15%36%21%8%
720
21st to endNight
30%20%29%18%3
792
November1st to 10thNight
27%19%31%18%5%
825
11th to 20thNight
25%21%31%17%6%1
850
21st to endNight
28%22%31%16%3
850
December1st to 10thNight
31%17%33%16%3
850
11th to 20thNight
31%21%33%13%2
850
21st to endNight
29%22%28%18%31
935
Page generated at 2024-01-19 10:28:36. Version ac07

Copyright 2024 Attilla Danko


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