Saint John
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Saint John clear sky chart from 2005-11-05 to 2018-02-14.

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%
15554
14%
48741
5%
15511
31%
15511
13%
34998

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
13%
814
14%
2861
2%
810
27%
810
9%
2014
January16th to endNight
12%
832
16%
2766
2%
832
29%
832
11%
1933
February1st to 15thNight
12%
760
13%
2466
3%
757
24%
757
11%
1743
February16th to endNight
16%
631
12%
1985
2%
631
27%
631
10%
1477
March1st to 15thNight
15%
720
15%
2023
4%
720
27%
720
14%
1498
March16th to endNight
20%
768
17%
2112
6%
768
29%
768
15%
1525
April1st to 15thNight
18%
596
14%
1783
6%
596
26%
596
13%
1332
April16th to endNight
20%
540
14%
1620
4%
540
29%
540
15%
1168
May1st to 15thNight
22%
540
10%
1593
5%
540
28%
540
12%
1213
May16th to endNight
24%
561
9%
1496
3%
560
30%
560
14%
1174
June1st to 15thNight
24%
365
7%
1265
4%
365
28%
365
10%
979
June16th to endNight
29%
360
7%
1260
6%
360
32%
360
11%
950
July1st to 15thNight
36%
340
8%
1190
9%
340
39%
340
13%
851
July16th to endNight
31%
488
7%
1462
6%
457
36%
457
12%
1123
August1st to 15thNight
40%
539
10%
1608
7%
535
42%
535
15%
1204
August16th to endNight
39%
573
17%
1725
10%
573
45%
573
21%
1172
September1st to 15thNight
33%
606
15%
1866
9%
606
40%
606
21%
1259
September16th to endNight
35%
717
24%
1980
13%
717
44%
717
26%
1281
October1st to 15thNight
30%
720
19%
2146
9%
720
38%
720
20%
1443
October16th to endNight
21%
768
16%
2355
4%
768
32%
768
16%
1653
November1st to 15thNight
24%
786
15%
2583
7%
786
33%
786
15%
1791
November16th to endNight
18%
825
15%
2730
4%
825
30%
825
12%
1919
December1st to 15thNight
10%
825
13%
2746
2%
825
23%
825
9%
2042
December16th to endNight
8%
880
13%
3120
1%
880
22%
880
7%
2254

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%7%35%42445%6%33%
49333
Night
22%8%35%424446%32%
48912
TransparencyDay
51%6%11%19%10%1
49022
Night
52%5%10%19%10%
48741
SeeingDay
25%18%26%20%7%1
7371
Night
24%23%25%19%6%
15554

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
16%11%36%33445%8%32%
1404
16th to endDay
17%10%35%5%2445%8%32%
1807
February1st to 15thDay
16%10%35%6%35%5%5%7%29%
1696
16th to endDay
13%11%47%5%3445%7%31%
1485
March1st to 15thDay
19%9%46%5%34346%30%
1925
16th to endDay
16%9%35%434346%37%
2112
April1st to 15thDay
22%9%36%5%34245%33%
2164
16th to endDay
24%6%25%423447%34%
2340
May1st to 15thDay
26%8%35%5%2445%5%29%
2359
16th to endDay
26%6%35%42445%7%27%
2624
June1st to 15thDay
26%8%37%5%35%345%26%
2700
16th to endDay
28%6%25%424447%29%
2700
July1st to 15thDay
21%6%25%5%3445%7%34%
2700
16th to endDay
21%8%35%4245%6%7%30%
2587
August1st to 15thDay
19%7%25%43446%7%34%
2340
16th to endDay
15%5%25%425%46%7%40%
2477
September1st to 15thDay
20%5%1331345%6%42%
2092
16th to endDay
19%413423346%47%
1980
October1st to 15thDay
19%5%14423445%43%
1812
16th to endDay
20%7%35%5%23446%36%
1866
November1st to 15thDay
23%6%25%5%23346%35%
1605
16th to endDay
21%7%26%5%2445%7%32%
1560
December1st to 15thDay
28%9%24323447%28%
1542
16th to endDay
24%8%36%5%23337%28%
1456
January1st to 15thNight
18%9%35%426%45%8%31%
2861
16th to endNight
17%10%36%5%345%5%9%30%
2766
February1st to 15thNight
18%9%35%425%5%5%8%30%
2465
16th to endNight
16%12%47%5%245%45%30%
1985
March1st to 15thNight
19%9%36%425%45%5%32%
2011
16th to endNight
18%9%35%424446%35%
2112
April1st to 15thNight
24%8%25%434345%30%
1783
16th to endNight
24%7%25%423446%32%
1620
May1st to 15thNight
27%8%35%5%345%46%26%
1593
16th to endNight
26%7%35%5%35%437%26%
1494
June1st to 15thNight
32%10%25%5%2335%8%21%
1265
16th to endNight
30%8%35%5%24336%26%
1260
July1st to 15thNight
24%8%36%42445%7%28%
1260
16th to endNight
25%9%35%5%345%47%24%
1566
August1st to 15thNight
23%8%25%4245%5%7%29%
1620
16th to endNight
17%8%245%1345%8%37%
1725
September1st to 15thNight
22%6%23432347%37%
1866
16th to endNight
18%5%14323246%46%
1980
October1st to 15thNight
21%5%24424346%40%
2146
16th to endNight
23%7%245%23335%37%
2355
November1st to 15thNight
22%5%26%5%33446%36%
2583
16th to endNight
21%7%35%433446%34%
2730
December1st to 15thNight
28%9%35%323346%29%
2746
16th to endNight
24%11%35%42335%7%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
51%6%14%17%8%1
1405
16th to endDay
50%6%9%20%12%1
1807
February1st to 15thDay
54%6%12%17%8%1
1699
16th to endDay
51%5%13%18%8%1
1485
March1st to 15thDay
54%49%18%10%1
1936
16th to endDay
48%5%10%19%14%2
2112
April1st to 15thDay
55%38%16%13%2
2164
16th to endDay
49%411%17%14%2
2340
May1st to 15thDay
56%5%8%18%9%1
2359
16th to endDay
55%7%11%20%4
2628
June1st to 15thDay
61%5%9%15%6%1
2700
16th to endDay
54%8%10%17%8%
2700
July1st to 15thDay
48%8%14%18%9%
2541
16th to endDay
49%10%13%19%5%
2429
August1st to 15thDay
48%10%12%20%8%
2327
16th to endDay
42%8%14%24%10%
2477
September1st to 15thDay
42%7%13%23%12%1
2092
16th to endDay
39%5%9%27%17%1
1980
October1st to 15thDay
43%5%10%28%11%
1812
16th to endDay
49%5%10%22%10%
1866
November1st to 15thDay
51%5%13%17%12%
1605
16th to endDay
51%6%13%17%10%
1560
December1st to 15thDay
56%5%11%19%7%
1542
16th to endDay
55%5%10%15%12%
1456
January1st to 15thNight
50%7%12%18%9%1
2861
16th to endNight
50%6%11%21%9%
2766
February1st to 15thNight
51%6%12%18%10%
2466
16th to endNight
55%6%9%16%10%1
1985
March1st to 15thNight
53%5%8%17%12%1
2023
16th to endNight
50%5%8%18%14%1
2112
April1st to 15thNight
56%48%13%12%3
1783
16th to endNight
52%5%9%17%13%1
1620
May1st to 15thNight
58%5%9%16%8%1
1593
16th to endNight
57%7%10%16%7%
1496
June1st to 15thNight
63%49%16%31
1265
16th to endNight
60%5%8%16%8%
1260
July1st to 15thNight
54%5%12%18%8%
1190
16th to endNight
57%8%11%16%5%
1462
August1st to 15thNight
53%8%11%18%8%
1608
16th to endNight
45%6%12%25%9%
1725
September1st to 15thNight
47%410%23%13%
1866
16th to endNight
40%410%27%16%1
1980
October1st to 15thNight
46%49%26%12%1
2146
16th to endNight
50%411%21%11%
2355
November1st to 15thNight
50%5%13%18%11%1
2583
16th to endNight
51%6%12%18%10%
2730
December1st to 15thNight
57%5%8%20%7%
2746
16th to endNight
56%5%11%17%9%
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%25%24%25%
90
16th to endDay
21%25%38%12%1
239
February1st to 15thDay
23%28%28%15%2
277
16th to endDay
19%26%30%19%4
223
March1st to 15thDay
22%30%28%15%3
270
16th to endDay
24%24%29%15%5%
288
April1st to 15thDay
30%23%27%13%4
270
16th to endDay
24%18%29%18%6%2
270
May1st to 15thDay
32%17%27%14%6%
315
16th to endDay
29%20%25%16%6%
519
June1st to 15thDay
26%17%26%21%7%
495
16th to endDay
29%16%23%20%9%1
495
July1st to 15thDay
28%13%19%25%11%1
475
16th to endDay
26%14%21%25%9%1
382
August1st to 15thDay
25%9%20%30%12%1
313
16th to endDay
21%9%22%29%14%1
332
September1st to 15thDay
25%8%23%29%11%1
315
16th to endDay
20%9%27%28%13%2
314
October1st to 15thDay
21%14%24%24%10%4
273
16th to endDay
22%20%30%19%41
288
November1st to 15thDay
22%19%27%21%7%2
280
16th to endDay
26%26%28%12%4
285
December1st to 15thDay
32%21%30%12%3
267
16th to endDay
29%29%29%10%2
96
January1st to 15thNight
21%33%28%14%3
814
16th to endNight
19%31%31%13%3
832
February1st to 15thNight
22%29%31%14%1
760
16th to endNight
23%29%25%17%3
631
March1st to 15thNight
22%28%28%17%2
720
16th to endNight
20%28%27%18%5%
768
April1st to 15thNight
24%24%27%19%4
596
16th to endNight
23%22%28%20%4
540
May1st to 15thNight
27%20%22%20%6%1
540
16th to endNight
24%23%23%21%5%
561
June1st to 15thNight
31%19%17%23%6%
365
16th to endNight
30%18%13%26%10%
360
July1st to 15thNight
30%14%12%30%12%1
340
16th to endNight
25%19%16%24%13%
488
August1st to 15thNight
25%11%15%29%16%1
539
16th to endNight
22%10%20%30%14%1
573
September1st to 15thNight
26%11%23%25%11%
606
16th to endNight
20%14%24%24%13%1
717
October1st to 15thNight
22%15%27%22%10%1
720
16th to endNight
26%20%29%18%5%
768
November1st to 15thNight
19%23%25%20%9%1
786
16th to endNight
21%31%25%15%6%
825
December1st to 15thNight
29%28%25%12%2
825
16th to endNight
29%31%26%10%2
880
Page generated at 2018-02-15 11:58:45. Version ac04

Copyright 2018 A. Danko


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