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 2018-02-22.

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
24%
15498
15%
48881
6%
15459
34%
15459
16%
34123

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%
814
14%
2864
2%
810
29%
810
11%
2012
January16th to endNight
16%
832
15%
2831
3%
832
31%
832
13%
1933
February1st to 15thNight
19%
764
13%
2481
4%
761
30%
761
15%
1728
February16th to endNight
17%
659
13%
2065
2%
659
29%
659
12%
1516
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
27%
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
31%
540
16%
1162
May16th to endNight
22%
504
10%
1439
3%
503
29%
503
14%
1107
June1st to 15thNight
27%
360
7%
1260
4%
360
31%
360
13%
936
June16th to endNight
33%
360
8%
1260
6%
360
37%
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%
539
10%
1608
9%
535
43%
535
21%
1092
August16th to endNight
39%
573
19%
1719
9%
573
46%
573
28%
1062
September1st to 15thNight
32%
624
15%
1869
8%
624
39%
624
23%
1226
September16th to endNight
38%
717
24%
1980
13%
717
48%
717
32%
1203
October1st to 15thNight
32%
720
19%
2134
9%
720
41%
720
25%
1380
October16th to endNight
21%
768
16%
2387
5%
768
33%
768
15%
1693
November1st to 15thNight
25%
784
15%
2576
8%
784
34%
784
16%
1769
November16th to endNight
23%
825
15%
2730
6%
825
35%
825
13%
1928
December1st to 15thNight
15%
825
14%
2818
3%
825
27%
825
12%
2036
December16th to endNight
11%
880
14%
3120
3%
880
25%
880
9%
2280

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%
49380
Night
20%8%35%5%2445%6%34%
49048
TransparencyDay
51%5%11%20%10%1
49065
Night
50%5%11%21%10%
48881
SeeingDay
27%14%29%19%8%1
7261
Night
25%13%31%22%6%
15498

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
17%10%47%6%3345%5%32%
1404
16th to endDay
16%10%46%5%34346%34%
1743
February1st to 15thDay
14%9%47%6%46%5%46%31%
1710
16th to endDay
16%12%48%6%34446%27%
1555
March1st to 15thDay
21%12%45%5%25%33431%
1906
16th to endDay
16%10%48%6%34345%32%
2112
April1st to 15thDay
22%10%36%424445%30%
2181
16th to endDay
26%7%24422446%33%
2340
May1st to 15thDay
26%8%35%5%34346%29%
2356
16th to endDay
27%6%35%5%24446%29%
2684
June1st to 15thDay
27%8%37%5%34446%25%
2700
16th to endDay
26%6%36%5%35%45%7%26%
2700
July1st to 15thDay
16%5%24435%5%6%9%33%
2700
16th to endDay
19%6%35%436%5%7%9%28%
2639
August1st to 15thDay
20%6%25%5%36%45%7%31%
2340
16th to endDay
14%5%25%5%35%5%5%7%38%
2483
September1st to 15thDay
16%6%35%334446%41%
2090
16th to endDay
16%5%23423345%49%
1980
October1st to 15thDay
20%6%25%323345%42%
1825
16th to endDay
22%7%36%5%3325%5%33%
1836
November1st to 15thDay
23%6%25%5%33446%35%
1611
16th to endDay
23%8%35%424446%32%
1560
December1st to 15thDay
27%8%25%425%335%30%
1469
16th to endDay
23%11%46%5%23445%28%
1456
January1st to 15thNight
16%9%47%6%3445%6%32%
2864
16th to endNight
15%10%36%5%35%46%7%31%
2831
February1st to 15thNight
15%11%36%5%35%45%7%32%
2480
16th to endNight
18%13%46%5%3445%5%29%
2065
March1st to 15thNight
19%9%35%5%25%44434%
2031
16th to endNight
18%9%45%5%24445%35%
2112
April1st to 15thNight
24%9%25%5%25%34431%
1765
16th to endNight
25%7%24323345%35%
1620
May1st to 15thNight
24%6%26%5%34447%29%
1596
16th to endNight
23%7%36%6%35%446%28%
1437
June1st to 15thNight
26%7%345%35%5%5%7%26%
1260
16th to endNight
23%4345%2445%7%32%
1260
July1st to 15thNight
15%435%5%347%5%8%36%
1260
16th to endNight
19%6%25%435%5%6%8%30%
1514
August1st to 15thNight
17%6%35%5%3445%7%36%
1620
16th to endNight
14%5%1432446%7%43%
1719
September1st to 15thNight
18%6%25%43335%6%40%
1869
16th to endNight
14%313422436%51%
1980
October1st to 15thNight
19%42442335%7%41%
2134
16th to endNight
24%6%25%5%24445%34%
2387
November1st to 15thNight
22%6%25%5%24445%36%
2576
16th to endNight
22%8%35%423446%34%
2730
December1st to 15thNight
26%9%35%424435%31%
2818
16th to endNight
24%10%45%5%23445%28%
3120

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
53%5%14%17%7%1
1405
16th to endDay
51%310%22%11%
1743
February1st to 15thDay
53%6%11%19%8%1
1713
16th to endDay
57%411%17%7%1
1555
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
2181
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%
2477
August1st to 15thDay
50%5%13%23%6%
2327
16th to endDay
42%6%15%25%9%
2483
September1st to 15thDay
43%5%13%25%12%
2090
16th to endDay
37%310%28%17%1
1980
October1st to 15thDay
44%412%27%10%
1825
16th to endDay
52%411%22%8%
1836
November1st to 15thDay
50%414%16%12%
1611
16th to endDay
52%5%15%18%8%
1560
December1st to 15thDay
57%311%19%7%
1469
16th to endDay
57%38%18%10%1
1456
January1st to 15thNight
51%6%12%19%9%
2864
16th to endNight
50%411%22%10%
2831
February1st to 15thNight
50%413%20%10%
2481
16th to endNight
56%410%16%10%2
2065
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%22%7%
1608
16th to endNight
37%5%17%29%9%
1719
September1st to 15thNight
43%5%11%26%12%1
1869
16th to endNight
34%413%30%16%1
1980
October1st to 15thNight
42%412%27%13%
2134
16th to endNight
51%49%22%10%
2387
November1st to 15thNight
50%414%20%9%1
2576
16th to endNight
51%5%12%19%9%
2730
December1st to 15thNight
56%39%22%7%
2818
16th to endNight
58%49%18%8%
3120

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
24%23%37%13%1
90
16th to endDay
24%22%33%14%4
175
February1st to 15thDay
22%17%33%22%3
281
16th to endDay
24%20%30%20%4
245
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%5%30%23%13%2
313
16th to endDay
19%10%24%26%15%4
332
September1st to 15thDay
20%9%30%27%9%2
315
16th to endDay
18%12%29%22%12%4
314
October1st to 15thDay
26%13%25%17%13%3
276
16th to endDay
29%19%31%11%7%
288
November1st to 15thDay
30%11%28%19%8%1
280
16th to endDay
29%18%27%18%5%
285
December1st to 15thDay
35%16%26%15%4
194
16th to endDay
34%26%28%11%
96
January1st to 15thNight
23%18%33%20%3
814
16th to endNight
21%20%33%20%3
832
February1st to 15thNight
21%17%34%21%4
764
16th to endNight
25%19%31%18%4
659
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%
539
16th to endNight
17%5%32%28%15%
573
September1st to 15thNight
23%8%31%27%9%
624
16th to endNight
17%10%29%29%12%
717
October1st to 15thNight
21%10%31%24%10%1
720
16th to endNight
27%16%30%18%6%
768
November1st to 15thNight
25%12%31%21%7%1
784
16th to endNight
26%18%26%20%7%
825
December1st to 15thNight
33%15%29%18%3
825
16th to endNight
32%19%28%15%2
880
Page generated at 2018-02-23 12:21:37. Version ac04

Copyright 2018 A. Danko


Fredericton Clear Sky Chart |Charts Home