Matagami
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Matagami clear sky chart from 2005-11-05 to 2017-09-24.

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
25%
14922
8%
46793
5%
14890
28%
14890
11%
37557

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
17%
900
4%
2685
3%
895
19%
895
5%
2401
January16th to endNight
25%
846
5%
2763
3%
846
28%
846
6%
2369
February1st to 15thNight
31%
704
8%
2287
6%
701
34%
701
7%
1944
February16th to endNight
22%
631
7%
2039
5%
631
26%
631
8%
1692
March1st to 15thNight
25%
720
13%
2063
9%
720
29%
720
13%
1630
March16th to endNight
28%
768
13%
2067
6%
768
33%
768
15%
1626
April1st to 15thNight
25%
718
12%
1796
5%
718
28%
718
15%
1424
April16th to endNight
32%
491
14%
1571
11%
491
37%
491
17%
1144
May1st to 15thNight
31%
360
12%
1440
11%
360
39%
360
14%
1003
May16th to endNight
31%
374
7%
1453
6%
374
36%
374
13%
1040
June1st to 15thNight
33%
360
5%
1260
1%
360
35%
360
17%
851
June16th to endNight
40%
360
4%
1260
1%
360
41%
360
20%
837
July1st to 15thNight
37%
340
4%
1190
2%
340
37%
340
18%
827
July16th to endNight
48%
376
10%
1323
12%
354
50%
354
19%
876
August1st to 15thNight
40%
404
8%
1475
9%
402
43%
402
16%
1068
August16th to endNight
35%
612
11%
1758
8%
612
37%
612
19%
1271
September1st to 15thNight
31%
720
8%
1800
3%
720
33%
720
20%
1371
September16th to endNight
32%
693
13%
1908
7%
693
35%
693
20%
1401
October1st to 15thNight
24%
660
11%
1980
8%
660
28%
660
13%
1554
October16th to endNight
16%
704
6%
2222
5%
704
19%
704
5%
1972
November1st to 15thNight
13%
700
5%
2452
4%
700
16%
700
5%
2113
November16th to endNight
11%
720
3%
2520
1%
720
13%
720
4%
2242
December1st to 15thNight
14%
801
2%
2601
1%
801
15%
801
5%
2320
December16th to endNight
19%
960
5%
2880
3%
960
21%
960
5%
2581

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
20%13%47%6%35%445%22%
48158
Night
18%14%5%8%6%36%5%45%20%
46949
TransparencyDay
62%5%9%15%6%
47831
Night
65%5%9%13%5%
46794
SeeingDay
26%10%28%22%9%2
5939
Night
26%9%29%23%9%1
14923

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%17%7%12%8%48%7%5%46%
1253
16th to endDay
11%15%5%13%7%49%10%7%5%8%
1461
February1st to 15thDay
7%12%7%10%11%6%9%8%8%5%11%
1575
16th to endDay
11%17%6%11%11%45%6%5%313%
1434
March1st to 15thDay
13%13%5%9%7%27%7%5%5%21%
1885
16th to endDay
12%15%46%7%46%5%45%27%
2157
April1st to 15thDay
22%13%7%8%5%2434422%
2159
16th to endDay
18%13%47%5%33336%30%
2391
May1st to 15thDay
21%12%36%6%24345%28%
2511
16th to endDay
25%11%46%5%14335%28%
2660
June1st to 15thDay
21%9%245%35%45%7%30%
2700
16th to endDay
19%7%35%5%35%5%5%7%32%
2700
July1st to 15thDay
22%8%36%5%4445%6%28%
2700
16th to endDay
20%8%26%6%35%5%6%7%26%
2754
August1st to 15thDay
25%9%36%5%45%445%23%
2472
16th to endDay
21%10%37%6%45%346%26%
2432
September1st to 15thDay
25%8%26%5%24446%27%
2160
16th to endDay
28%9%36%424345%27%
1907
October1st to 15thDay
26%16%46%5%32335%22%
1650
16th to endDay
33%26%47%42222211%
1648
November1st to 15thDay
26%23%8%8%6%2223312%
1406
16th to endDay
25%21%8%9%7%25%22310%
1440
December1st to 15thDay
18%23%9%12%7%45%3438%
1359
16th to endDay
15%15%7%14%10%5%7%5%5%48%
1344
January1st to 15thNight
19%17%7%11%8%48%7%436%
2685
16th to endNight
11%15%7%11%9%5%9%9%6%48%
2763
February1st to 15thNight
7%13%7%10%10%6%13%9%6%5%9%
2285
16th to endNight
12%17%6%12%8%47%7%5%5%12%
2039
March1st to 15thNight
13%12%5%10%8%5%7%5%45%21%
2051
16th to endNight
13%13%5%8%8%5%6%5%35%25%
2067
April1st to 15thNight
22%14%5%7%435%345%25%
1796
16th to endNight
20%10%37%5%25%445%31%
1571
May1st to 15thNight
17%10%46%6%35%346%30%
1440
16th to endNight
22%10%35%435%45%5%28%
1452
June1st to 15thNight
19%8%37%425%446%34%
1260
16th to endNight
14%6%25%6%35%45%8%35%
1260
July1st to 15thNight
19%5%35%435%5%6%8%31%
1260
16th to endNight
16%7%15%435%45%8%37%
1414
August1st to 15thNight
21%8%46%5%25%345%31%
1485
16th to endNight
15%9%36%5%35%5%5%7%32%
1758
September1st to 15thNight
21%9%36%5%23346%31%
1800
16th to endNight
23%9%35%5%33326%34%
1908
October1st to 15thNight
26%12%37%43435%5%23%
1980
16th to endNight
30%25%5%5%5%2332212%
2222
November1st to 15thNight
26%22%6%8%5%2333313%
2452
16th to endNight
24%20%8%11%7%2423310%
2520
December1st to 15thNight
19%19%8%13%9%45%4338%
2601
16th to endNight
16%18%9%13%9%47%5%348%
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
77%46%8%1
1254
16th to endDay
71%6%8%9%4
1461
February1st to 15thDay
67%5%8%11%6%
1577
16th to endDay
72%37%12%3
1434
March1st to 15thDay
61%47%14%10%
1896
16th to endDay
57%39%19%9%
2157
April1st to 15thDay
65%37%14%8%1
2159
16th to endDay
56%48%16%12%1
2391
May1st to 15thDay
57%5%8%15%11%1
2511
16th to endDay
58%48%17%9%
2664
June1st to 15thDay
52%48%20%12%
2700
16th to endDay
51%6%9%21%10%
2700
July1st to 15thDay
53%6%11%21%7%
2541
16th to endDay
56%7%13%16%5%
2582
August1st to 15thDay
61%7%13%15%2
2458
16th to endDay
58%6%13%17%4
2432
September1st to 15thDay
56%6%13%16%6%
2160
16th to endDay
59%5%12%20%3
1907
October1st to 15thDay
66%5%11%10%6%
1650
16th to endDay
81%35%7%1
1648
November1st to 15thDay
77%46%7%2
1406
16th to endDay
81%48%5%1
1440
December1st to 15thDay
79%45%8%2
1359
16th to endDay
78%5%6%6%2
1344
January1st to 15thNight
79%47%6%1
2685
16th to endNight
73%6%7%8%4
2763
February1st to 15thNight
72%5%7%8%6%
2287
16th to endNight
70%5%7%12%3
2039
March1st to 15thNight
64%38%14%8%
2063
16th to endNight
61%47%16%9%
2067
April1st to 15thNight
61%45%15%10%1
1796
16th to endNight
54%48%19%11%1
1571
May1st to 15thNight
52%6%9%17%12%1
1440
16th to endNight
55%6%8%18%11%
1454
June1st to 15thNight
50%5%8%21%13%1
1260
16th to endNight
44%7%11%22%12%1
1260
July1st to 15thNight
47%8%12%22%7%
1190
16th to endNight
45%7%15%25%5%
1323
August1st to 15thNight
53%6%16%18%4
1475
16th to endNight
48%8%18%20%4
1758
September1st to 15thNight
53%7%15%16%7%
1800
16th to endNight
53%415%21%4
1908
October1st to 15thNight
62%5%11%15%5%
1980
16th to endNight
78%46%8%2
2222
November1st to 15thNight
76%49%6%2
2452
16th to endNight
79%5%8%5%1
2520
December1st to 15thNight
80%37%6%1
2601
16th to endNight
79%46%6%2
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
20%13%33%25%6%1
60
16th to endDay
35%429%21%6%3
65
February1st to 15thDay
12%10%36%30%11%
90
16th to endDay
25%9%39%21%3
93
March1st to 15thDay
20%13%30%25%8%1
270
16th to endDay
22%11%33%22%8%1
288
April1st to 15thDay
24%12%34%15%11%1
270
16th to endDay
20%14%31%21%7%3
270
May1st to 15thDay
31%8%26%20%8%4
288
16th to endDay
32%10%24%20%8%3
373
June1st to 15thDay
28%11%25%22%10%1
495
16th to endDay
21%11%28%24%9%4
495
July1st to 15thDay
27%8%29%21%10%2
475
16th to endDay
22%8%28%28%9%2
425
August1st to 15thDay
31%6%20%23%11%6%
313
16th to endDay
30%5%25%20%12%5%
332
September1st to 15thDay
21%11%25%23%14%3
315
16th to endDay
28%9%24%25%9%2
287
October1st to 15thDay
26%9%30%21%8%3
255
16th to endDay
42%10%22%16%5%2
236
November1st to 15thDay
33%16%33%15%1
60
16th to endDay
41%16%28%10%3
60
December1st to 15thDay
30%6%36%16%8%1
60
16th to endDay
18%18%42%9%10%
64
January1st to 15thNight
29%10%30%22%6%
900
16th to endNight
19%10%32%22%12%2
846
February1st to 15thNight
14%8%33%29%11%1
704
16th to endNight
22%9%31%24%11%
631
March1st to 15thNight
19%14%31%23%10%
720
16th to endNight
20%11%33%24%9%
768
April1st to 15thNight
29%12%27%24%6%
718
16th to endNight
26%6%28%28%7%1
491
May1st to 15thNight
23%10%29%27%8%
360
16th to endNight
29%11%23%27%7%1
375
June1st to 15thNight
24%9%28%27%9%
360
16th to endNight
15%6%31%34%9%1
360
July1st to 15thNight
19%6%31%31%10%1
340
16th to endNight
18%323%37%15%
376
August1st to 15thNight
25%421%30%17%1
404
16th to endNight
22%5%30%25%14%1
612
September1st to 15thNight
27%8%27%22%12%1
720
16th to endNight
28%8%25%25%11%
693
October1st to 15thNight
31%11%28%20%7%
660
16th to endNight
46%8%19%16%6%2
704
November1st to 15thNight
38%12%28%13%5%1
700
16th to endNight
33%12%31%17%3
720
December1st to 15thNight
28%10%31%21%6%1
801
16th to endNight
25%9%30%20%11%1
960
Page generated at 2017-09-25 09:02:29. Version ac04

Copyright 2017 A. Danko


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