Wemindji
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wemindji clear sky chart from 2005-11-05 to 2017-09-19.

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
33%
15087
6%
46754
5%
15058
34%
15058
10%
38022

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
25%
897
1%
2685
1%
895
25%
895
4%
2475
January16th to endNight
37%
960
6%
2880
4%
960
39%
960
7%
2514
February1st to 15thNight
45%
731
7%
2350
7%
728
47%
728
8%
1992
February16th to endNight
43%
631
8%
2051
9%
631
44%
631
11%
1642
March1st to 15thNight
44%
720
15%
2085
13%
720
47%
720
18%
1536
March16th to endNight
44%
768
13%
2082
9%
768
46%
768
18%
1592
April1st to 15thNight
37%
648
12%
1726
7%
648
40%
648
18%
1325
April16th to endNight
46%
465
15%
1545
17%
465
49%
465
20%
1054
May1st to 15thNight
33%
360
8%
1425
9%
360
36%
360
16%
954
May16th to endNight
38%
374
3%
1309
1%
374
38%
374
16%
910
June1st to 15thNight
50%
360
0%
1095
0%
360
50%
360
27%
699
June16th to endNight
46%
360
0%
1080
0%
360
46%
360
24%
727
July1st to 15thNight
42%
340
0%
1166
0%
340
42%
340
15%
855
July16th to endNight
46%
376
3%
1240
2%
354
45%
354
15%
901
August1st to 15thNight
40%
368
6%
1393
9%
366
41%
366
12%
1019
August16th to endNight
43%
573
9%
1719
8%
573
44%
573
16%
1310
September1st to 15thNight
35%
704
8%
1784
5%
704
36%
704
17%
1393
September16th to endNight
30%
673
9%
1864
5%
673
32%
673
14%
1477
October1st to 15thNight
21%
660
7%
1980
5%
660
25%
660
10%
1635
October16th to endNight
21%
704
4%
2311
4%
704
22%
704
6%
2020
November1st to 15thNight
10%
700
3%
2452
2%
700
12%
700
4%
2204
November16th to endNight
13%
800
2%
2625
1%
800
14%
800
3%
2438
December1st to 15thNight
17%
930
2%
2880
1%
930
18%
930
3%
2671
December16th to endNight
30%
985
5%
3027
4%
985
30%
985
6%
2679

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
17%12%48%7%45%5%5%6%23%
48084
Night
17%14%5%9%8%46%6%4417%
46902
TransparencyDay
60%6%11%15%5%
47748
Night
66%5%9%12%4
46756
SeeingDay
23%422%27%16%5%
6444
Night
22%5%22%29%16%3
15091

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%13%6%15%13%8%10%10%411
1253
16th to endDay
7%13%7%13%13%7%10%11%6%35%
1344
February1st to 15thDay
6%10%5%11%9%8%14%12%9%5%5%
1512
16th to endDay
10%16%49%8%6%9%11%6%5%11%
1422
March1st to 15thDay
9%9%6%9%8%5%8%10%8%5%17%
1861
16th to endDay
9%9%48%9%6%9%8%5%6%23%
2142
April1st to 15thDay
15%11%5%9%7%46%445%25%
2232
16th to endDay
12%9%5%6%7%34445%35%
2415
May1st to 15thDay
18%10%5%7%5%24446%30%
2524
16th to endDay
14%8%5%7%5%345%6%8%29%
2804
June1st to 15thDay
15%7%35%43335%8%40%
2865
16th to endDay
15%6%36%5%25%45%7%37%
2880
July1st to 15thDay
18%10%46%5%25%5%5%9%26%
2721
16th to endDay
16%8%37%6%25%46%8%29%
2844
August1st to 15thDay
20%11%26%435%46%7%27%
2555
16th to endDay
21%9%26%42445%6%30%
2483
September1st to 15thDay
22%11%37%5%33446%26%
2164
16th to endDay
30%12%26%42435%6%21%
1841
October1st to 15thDay
29%19%5%6%6%2332416%
1650
16th to endDay
31%21%5%8%5%1333412%
1560
November1st to 15thDay
28%28%6%8%5%222239%
1406
16th to endDay
21%21%12%15%9%332325%
1332
December1st to 15thDay
12%19%10%14%16%5%5%2128%
1080
16th to endDay
11%15%8%11%12%8%10%5%239%
1194
January1st to 15thNight
16%15%6%13%11%6%10%10%322
2685
16th to endNight
10%12%6%11%12%8%11%10%6%27%
2880
February1st to 15thNight
5%8%5%12%11%7%14%13%9%38%
2348
16th to endNight
7%14%7%9%9%5%8%11%7%6%11%
2051
March1st to 15thNight
8%8%5%8%8%48%9%7%7%23%
2073
16th to endNight
10%9%47%7%5%9%7%5%7%25%
2082
April1st to 15thNight
16%12%48%6%45%346%27%
1726
16th to endNight
13%9%36%6%34347%35%
1545
May1st to 15thNight
20%9%46%414436%34%
1425
16th to endNight
19%8%37%4245%5%7%30%
1309
June1st to 15thNight
17%5%35%42445%7%38%
1095
16th to endNight
13%7%25%5%45%5%5%6%37%
1080
July1st to 15thNight
18%11%5%7%6%345%47%25%
1236
16th to endNight
18%11%46%5%346%5%7%26%
1324
August1st to 15thNight
22%9%37%5%35%446%26%
1401
16th to endNight
19%11%26%5%35%447%29%
1719
September1st to 15thNight
21%10%37%425%5%5%5%27%
1784
16th to endNight
25%12%46%6%2435%5%23%
1864
October1st to 15thNight
28%15%48%433435%18%
1980
16th to endNight
30%22%5%8%5%2323312%
2311
November1st to 15thNight
29%29%6%8%5%222238%
2452
16th to endNight
20%24%10%16%6%332325%
2625
December1st to 15thNight
13%20%11%14%15%5%5%2127%
2880
16th to endNight
12%15%7%11%12%9%9%5%437%
3027

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
84%6%5%3
1254
16th to endDay
77%46%7%3
1344
February1st to 15thDay
67%8%8%10%4
1514
16th to endDay
65%6%11%12%2
1422
March1st to 15thDay
60%5%9%16%7%
1872
16th to endDay
59%412%14%7%
2142
April1st to 15thDay
60%37%17%9%
2232
16th to endDay
52%48%19%14%
2415
May1st to 15thDay
54%48%22%8%
2524
16th to endDay
50%6%13%19%8%
2808
June1st to 15thDay
42%5%10%27%14%
2865
16th to endDay
44%6%14%22%11%
2880
July1st to 15thDay
50%7%14%21%5%
2562
16th to endDay
49%8%17%20%3
2665
August1st to 15thDay
54%9%17%14%2
2539
16th to endDay
53%8%15%20%2
2483
September1st to 15thDay
59%8%14%14%2
2164
16th to endDay
66%413%13%2
1841
October1st to 15thDay
73%49%10%2
1650
16th to endDay
77%5%8%8%1
1560
November1st to 15thDay
82%27%5%1
1406
16th to endDay
84%46%3
1332
December1st to 15thDay
82%46%41
1080
16th to endDay
78%48%6%1
1194
January1st to 15thNight
81%6%8%2
2685
16th to endNight
75%5%7%7%3
2880
February1st to 15thNight
69%7%7%11%3
2350
16th to endNight
64%6%11%14%2
2051
March1st to 15thNight
53%5%11%20%8%
2085
16th to endNight
55%6%9%16%10%
2082
April1st to 15thNight
58%48%16%11%
1726
16th to endNight
50%37%20%16%
1545
May1st to 15thNight
51%49%22%11%1
1425
16th to endNight
53%49%19%12%1
1311
June1st to 15thNight
42%311%25%15%
1095
16th to endNight
43%7%11%23%13%1
1080
July1st to 15thNight
55%6%11%21%5%
1166
16th to endNight
55%5%17%17%4
1240
August1st to 15thNight
58%5%13%19%3
1393
16th to endNight
55%8%14%17%2
1719
September1st to 15thNight
55%8%18%14%3
1784
16th to endNight
60%6%13%15%3
1864
October1st to 15thNight
67%6%11%11%3
1980
16th to endNight
77%49%6%1
2311
November1st to 15thNight
81%47%5%
2452
16th to endNight
84%5%6%3
2625
December1st to 15thNight
84%45%4
2880
16th to endNight
77%49%6%2
3027

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
18%133%21%16%8%
60
16th to endDay
21%425%29%14%4
64
February1st to 15thDay
11%116%33%27%9%
84
16th to endDay
23%323%35%12%1
81
March1st to 15thDay
13%7%20%29%19%10%
234
16th to endDay
13%326%34%17%4
288
April1st to 15thDay
17%424%28%17%7%
270
16th to endDay
17%7%27%22%16%8%
270
May1st to 15thDay
22%423%26%15%7%
301
16th to endDay
17%6%26%27%16%5%
517
June1st to 15thDay
18%5%23%28%19%5%
660
16th to endDay
20%319%34%17%4
675
July1st to 15thDay
23%425%26%17%3
496
16th to endDay
22%223%28%17%5%
515
August1st to 15thDay
29%313%24%18%10%
360
16th to endDay
30%412%26%16%8%
332
September1st to 15thDay
30%5%22%26%12%2
315
16th to endDay
34%429%16%13%2
266
October1st to 15thDay
40%5%20%18%10%4
255
16th to endDay
41%317%17%12%7%
157
November1st to 15thDay
40%10%23%20%33
60
16th to endDay
30%11%15%25%13%5%
60
December1st to 15thDay
20%128%25%21%3
60
16th to endDay
17%137%23%18%1
64
January1st to 15thNight
21%6%24%29%16%2
900
16th to endNight
14%418%30%24%6%
960
February1st to 15thNight
7%320%40%23%4
731
16th to endNight
14%315%30%25%10%
631
March1st to 15thNight
11%5%23%34%20%4
720
16th to endNight
14%5%23%35%17%3
768
April1st to 15thNight
20%425%30%15%3
648
16th to endNight
17%5%22%32%19%2
465
May1st to 15thNight
26%426%24%13%3
360
16th to endNight
21%5%25%32%14%1
375
June1st to 15thNight
18%320%32%23%1
360
16th to endNight
16%225%35%18%2
360
July1st to 15thNight
20%321%32%20%1
340
16th to endNight
22%216%33%23%2
376
August1st to 15thNight
27%215%29%23%2
368
16th to endNight
25%317%32%16%4
573
September1st to 15thNight
26%6%23%27%15%1
704
16th to endNight
33%423%25%10%1
673
October1st to 15thNight
37%8%24%19%9%
660
16th to endNight
39%5%17%20%13%3
704
November1st to 15thNight
40%9%27%13%7%1
700
16th to endNight
29%8%25%25%10%1
800
December1st to 15thNight
19%8%28%30%13%1
930
16th to endNight
16%425%30%16%6%
985
Page generated at 2017-09-20 04:49:52. Version ac04

Copyright 2017 A. Danko


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