Fredericton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fredericton clear sky chart from 2005-11-05 to 2017-08-12.

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%
14681
14%
46411
6%
14642
33%
14642
16%
32462

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 15thNight
15%
743
14%
2642
2%
739
30%
739
12%
1839
January16th to endNight
16%
768
15%
2613
3%
768
31%
768
13%
1779
February1st to 15thNight
19%
704
12%
2286
3%
701
30%
701
15%
1589
February16th to endNight
18%
631
12%
1976
2%
631
29%
631
12%
1454
March1st to 15thNight
19%
720
17%
2043
6%
720
30%
720
16%
1486
March16th to endNight
19%
768
17%
2112
5%
768
29%
768
18%
1511
April1st to 15thNight
18%
606
15%
1765
5%
606
26%
606
15%
1294
April16th to endNight
22%
540
16%
1620
7%
540
30%
540
18%
1134
May1st to 15thNight
25%
540
12%
1596
5%
540
32%
540
16%
1162
May16th to endNight
23%
504
10%
1439
3%
503
31%
503
14%
1107
June1st to 15thNight
26%
360
7%
1260
4%
360
31%
360
13%
936
June16th to endNight
32%
360
8%
1260
6%
360
35%
360
16%
869
July1st to 15thNight
38%
340
11%
1190
9%
340
44%
340
22%
771
July16th to endNight
35%
436
10%
1414
8%
409
40%
409
17%
995
August1st to 15thNight
42%
528
10%
1575
9%
524
44%
524
20%
1072
August16th to endNight
40%
525
17%
1575
9%
525
45%
525
28%
975
September1st to 15thNight
32%
571
15%
1712
8%
571
39%
571
23%
1128
September16th to endNight
37%
657
23%
1815
12%
657
47%
657
32%
1105
October1st to 15thNight
31%
660
20%
1957
10%
660
42%
660
24%
1278
October16th to endNight
21%
704
15%
2187
4%
704
32%
704
15%
1560
November1st to 15thNight
24%
716
15%
2373
8%
716
34%
716
16%
1628
November16th to endNight
24%
750
15%
2520
6%
750
36%
750
13%
1779
December1st to 15thNight
15%
750
13%
2601
3%
750
27%
750
11%
1881
December16th to endNight
12%
800
12%
2880
3%
800
24%
800
9%
2130

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
21%8%36%5%34446%32%
47566
Night
20%8%35%5%34446%33%
46578
TransparencyDay
52%5%11%19%9%1
47251
Night
50%5%11%21%10%
46411
SeeingDay
27%13%28%19%8%1
6675
Night
25%13%31%22%6%
14681

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 15thDay
15%11%46%5%3335%6%33%
1295
16th to endDay
16%10%46%6%25%346%33%
1611
February1st to 15thDay
13%10%47%6%45%5%5%6%31%
1575
16th to endDay
17%11%48%6%3445%6%27%
1497
March1st to 15thDay
20%12%36%5%24335%31%
1906
16th to endDay
16%10%48%6%34336%33%
2112
April1st to 15thDay
22%11%46%424346%30%
2180
16th to endDay
26%7%25%422436%34%
2340
May1st to 15thDay
26%8%35%5%24445%29%
2356
16th to endDay
27%7%35%5%24346%29%
2684
June1st to 15thDay
28%8%36%5%24345%26%
2700
16th to endDay
26%7%35%5%35%45%7%26%
2700
July1st to 15thDay
16%425%5%35%5%7%9%34%
2700
16th to endDay
18%6%35%5%36%6%7%9%28%
2637
August1st to 15thDay
20%6%26%5%36%45%6%32%
2288
16th to endDay
14%5%25%5%35%46%7%39%
2275
September1st to 15thDay
16%6%245%34446%40%
1916
16th to endDay
17%424422345%48%
1815
October1st to 15thDay
20%6%24423435%40%
1672
16th to endDay
24%6%27%6%24245%32%
1683
November1st to 15thDay
23%7%26%433346%34%
1484
16th to endDay
23%8%35%42435%6%31%
1440
December1st to 15thDay
27%8%25%424335%30%
1356
16th to endDay
23%12%46%5%13346%27%
1344
January1st to 15thNight
16%9%36%5%3445%6%32%
2642
16th to endNight
15%10%46%6%35%45%7%32%
2613
February1st to 15thNight
14%11%36%5%35%5%5%7%32%
2285
16th to endNight
18%13%36%43445%429%
1976
March1st to 15thNight
20%9%35%5%3444433%
2031
16th to endNight
17%9%46%5%34345%34%
2112
April1st to 15thNight
24%8%35%5%25%34431%
1765
16th to endNight
25%7%25%323445%35%
1620
May1st to 15thNight
25%6%25%5%3445%7%29%
1596
16th to endNight
22%8%36%6%46%445%27%
1437
June1st to 15thNight
26%7%35%5%35%45%7%25%
1260
16th to endNight
23%5%24425%5%5%6%33%
1260
July1st to 15thNight
14%5%35%5%347%6%8%36%
1260
16th to endNight
19%6%36%4345%7%8%29%
1514
August1st to 15thNight
17%6%36%5%34447%36%
1587
16th to endNight
14%42442446%8%43%
1575
September1st to 15thNight
19%5%24433347%40%
1712
16th to endNight
15%314312346%51%
1815
October1st to 15thNight
20%5%2442335%7%39%
1957
16th to endNight
24%7%35%5%33336%33%
2187
November1st to 15thNight
23%6%245%24445%35%
2373
16th to endNight
22%8%25%424346%34%
2520
December1st to 15thNight
26%9%35%42443430%
2601
16th to endNight
26%10%45%5%34345%27%
2880

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 15thDay
52%5%14%18%7%1
1296
16th to endDay
52%39%22%11%
1611
February1st to 15thDay
52%6%11%20%8%1
1578
16th to endDay
57%410%17%7%1
1497
March1st to 15thDay
57%39%16%10%2
1917
16th to endDay
53%38%19%11%2
2112
April1st to 15thDay
55%38%16%13%2
2180
16th to endDay
51%48%18%13%3
2340
May1st to 15thDay
57%48%19%9%2
2356
16th to endDay
55%5%11%19%6%
2688
June1st to 15thDay
59%5%9%14%8%1
2700
16th to endDay
56%5%11%17%8%
2700
July1st to 15thDay
42%8%14%20%12%
2541
16th to endDay
49%8%16%18%7%
2475
August1st to 15thDay
50%5%13%22%6%
2275
16th to endDay
42%6%16%25%9%
2275
September1st to 15thDay
43%5%13%24%12%
1916
16th to endDay
38%49%29%17%1
1815
October1st to 15thDay
45%412%26%10%
1672
16th to endDay
54%410%21%8%
1683
November1st to 15thDay
51%414%15%12%
1484
16th to endDay
52%5%14%18%8%
1440
December1st to 15thDay
57%312%19%6%
1356
16th to endDay
59%39%17%9%
1344
January1st to 15thNight
50%6%12%19%9%1
2642
16th to endNight
50%411%22%10%
2613
February1st to 15thNight
51%413%20%9%
2286
16th to endNight
56%410%16%10%2
1976
March1st to 15thNight
52%48%19%12%2
2043
16th to endNight
51%48%20%13%1
2112
April1st to 15thNight
55%48%16%12%3
1765
16th to endNight
50%49%18%13%2
1620
May1st to 15thNight
53%5%10%19%9%1
1596
16th to endNight
57%7%10%16%7%
1439
June1st to 15thNight
57%6%11%17%5%1
1260
16th to endNight
50%5%14%20%8%
1260
July1st to 15thNight
41%7%16%24%8%
1190
16th to endNight
49%8%13%19%8%
1414
August1st to 15thNight
47%5%15%23%7%
1575
16th to endNight
37%5%18%29%8%
1575
September1st to 15thNight
44%411%25%11%1
1712
16th to endNight
34%313%31%15%
1815
October1st to 15thNight
43%412%26%13%
1957
16th to endNight
52%49%22%10%
2187
November1st to 15thNight
50%414%20%9%1
2373
16th to endNight
52%5%12%19%9%
2520
December1st to 15thNight
56%410%22%6%
2601
16th to endNight
59%49%19%7%
2880

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 15thDay
26%18%38%15%1
60
16th to endDay
21%19%36%16%5%
139
February1st to 15thDay
19%15%36%24%4
236
16th to endDay
24%20%28%21%4
225
March1st to 15thDay
31%18%30%14%5%
270
16th to endDay
24%20%27%17%8%2
288
April1st to 15thDay
33%20%26%12%5%
270
16th to endDay
30%16%30%12%7%2
270
May1st to 15thDay
34%16%26%15%5%1
312
16th to endDay
30%15%30%15%7%
519
June1st to 15thDay
34%13%24%20%6%
495
16th to endDay
29%9%31%19%9%1
495
July1st to 15thDay
24%7%29%22%13%2
475
16th to endDay
22%5%30%27%11%2
383
August1st to 15thDay
24%429%24%14%2
297
16th to endDay
19%7%26%27%15%3
268
September1st to 15thDay
21%8%27%30%8%3
255
16th to endDay
19%13%31%19%11%5%
254
October1st to 15thDay
28%13%22%17%13%4
229
16th to endDay
30%17%32%10%7%
240
November1st to 15thDay
30%11%29%18%9%
235
16th to endDay
29%19%24%19%6%
240
December1st to 15thDay
34%15%26%17%5%
156
16th to endDay
35%21%28%14%
64
January1st to 15thNight
23%17%34%20%3
743
16th to endNight
20%20%34%20%3
768
February1st to 15thNight
20%16%36%20%4
704
16th to endNight
25%18%31%18%4
631
March1st to 15thNight
25%16%32%21%3
720
16th to endNight
23%16%33%20%6%
768
April1st to 15thNight
29%17%30%17%4
606
16th to endNight
30%12%31%19%5%
540
May1st to 15thNight
28%13%28%23%5%
540
16th to endNight
26%12%32%22%4
504
June1st to 15thNight
29%7%31%24%6%
360
16th to endNight
26%5%30%29%6%
360
July1st to 15thNight
17%435%32%10%
340
16th to endNight
22%5%30%30%10%
436
August1st to 15thNight
20%5%25%33%14%
528
16th to endNight
17%5%32%29%15%
525
September1st to 15thNight
23%7%31%26%9%
571
16th to endNight
17%10%29%29%11%
657
October1st to 15thNight
22%11%30%25%9%1
660
16th to endNight
27%16%30%18%6%
704
November1st to 15thNight
26%12%31%21%6%1
716
16th to endNight
26%17%25%21%8%
750
December1st to 15thNight
32%15%29%18%3
750
16th to endNight
33%18%28%15%2
800
Page generated at 2017-08-13 15:16:24. Version ac04

Copyright 2017 A. Danko


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