Observatoires de Rimouski
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatoires de Rimouski clear sky chart from 2005-11-05 to 2017-09-21.

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%
14627
9%
46837
5%
14595
28%
14595
11%
36001

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
10%
743
5%
2640
2%
739
15%
739
4%
2268
January16th to endNight
15%
768
9%
2688
3%
768
24%
768
6%
2185
February1st to 15thNight
17%
704
7%
2343
3%
701
23%
701
8%
1870
February16th to endNight
15%
631
6%
1940
2%
631
20%
631
8%
1597
March1st to 15thNight
21%
720
11%
2098
7%
720
26%
720
11%
1646
March16th to endNight
23%
768
15%
2109
6%
768
31%
768
15%
1583
April1st to 15thNight
20%
641
13%
1719
5%
641
25%
641
14%
1337
April16th to endNight
26%
540
16%
1620
8%
540
35%
540
17%
1151
May1st to 15thNight
26%
522
10%
1590
6%
522
30%
522
14%
1193
May16th to endNight
23%
375
9%
1310
5%
374
30%
374
10%
977
June1st to 15thNight
33%
360
6%
1260
4%
360
36%
360
16%
881
June16th to endNight
31%
360
6%
1260
4%
360
33%
360
14%
907
July1st to 15thNight
35%
340
7%
1190
5%
340
40%
340
16%
819
July16th to endNight
35%
376
8%
1362
8%
354
39%
354
15%
950
August1st to 15thNight
39%
473
9%
1544
8%
471
42%
471
19%
1062
August16th to endNight
35%
573
12%
1719
6%
573
40%
573
21%
1186
September1st to 15thNight
32%
675
12%
1860
6%
675
36%
675
23%
1286
September16th to endNight
31%
681
16%
1880
9%
681
36%
681
24%
1253
October1st to 15thNight
25%
660
17%
1922
7%
660
34%
660
19%
1330
October16th to endNight
20%
704
8%
2271
4%
704
25%
704
11%
1761
November1st to 15thNight
16%
713
14%
2355
6%
713
26%
713
10%
1815
November16th to endNight
18%
750
7%
2577
4%
750
23%
750
8%
2070
December1st to 15thNight
10%
750
3%
2700
0%
750
13%
750
4%
2339
December16th to endNight
10%
800
5%
2880
2%
800
14%
800
3%
2535

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%11%47%6%35%445%25%
48038
Night
17%11%48%7%45%445%25%
46996
TransparencyDay
60%411%15%6%
47715
Night
60%5%11%15%5%
46837
SeeingDay
29%15%28%17%7%1
6545
Night
25%15%29%20%7%
14627

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
12%15%8%11%11%6%6%5%5%411%
1295
16th to endDay
9%12%6%12%9%6%10%10%4413%
1536
February1st to 15thDay
8%13%6%10%9%8%12%7%45%13%
1518
16th to endDay
13%15%7%11%11%47%44316%
1531
March1st to 15thDay
16%13%7%8%7%46%6%4321%
1851
16th to endDay
15%15%6%9%5%3433426%
2112
April1st to 15thDay
22%14%5%7%5%23445%23%
2230
16th to endDay
22%12%36%42333432%
2340
May1st to 15thDay
22%12%36%5%23335%30%
2370
16th to endDay
25%10%36%434346%27%
2805
June1st to 15thDay
23%7%26%6%35%45%6%27%
2700
16th to endDay
25%8%46%5%35%45%6%24%
2700
July1st to 15thDay
20%8%36%5%25%5%6%7%28%
2700
16th to endDay
19%8%36%6%35%5%6%5%29%
2708
August1st to 15thDay
20%8%27%6%345%5%7%26%
2393
16th to endDay
17%7%36%5%3445%6%33%
2483
September1st to 15thDay
23%6%25%323446%37%
2097
16th to endDay
20%7%24424335%41%
1873
October1st to 15thDay
21%13%37%5%24335%28%
1708
16th to endDay
27%17%36%42333321%
1601
November1st to 15thDay
21%17%5%6%5%23325%23%
1503
16th to endDay
20%18%5%10%7%25%33417%
1380
December1st to 15thDay
19%17%5%13%11%6%5%32411%
1260
16th to endDay
17%16%7%14%11%46%4439%
1344
January1st to 15thNight
14%16%7%10%11%5%8%5%4412%
2640
16th to endNight
9%11%6%10%8%7%10%8%5%416%
2688
February1st to 15thNight
7%11%6%12%9%8%9%6%5%6%16%
2342
16th to endNight
13%17%7%9%8%5%6%44418%
1940
March1st to 15thNight
15%12%48%7%48%5%45%22%
2085
16th to endNight
14%12%5%8%6%35%33432%
2109
April1st to 15thNight
21%13%5%7%5%34345%25%
1719
16th to endNight
22%9%345%24345%33%
1620
May1st to 15thNight
22%10%47%5%2445%328%
1590
16th to endNight
22%9%37%6%35%43428%
1308
June1st to 15thNight
20%7%45%4445%5%6%30%
1260
16th to endNight
19%8%36%7%245%5%6%28%
1260
July1st to 15thNight
15%8%26%6%36%5%5%7%31%
1260
16th to endNight
14%8%27%5%36%5%6%7%33%
1457
August1st to 15thNight
14%6%36%6%45%5%7%8%31%
1554
16th to endNight
15%7%25%5%246%5%9%34%
1719
September1st to 15thNight
19%6%25%434345%40%
1860
16th to endNight
20%5%24413346%43%
1880
October1st to 15thNight
19%7%25%433445%38%
1922
16th to endNight
25%13%46%5%3333425%
2271
November1st to 15thNight
21%12%5%7%6%33345%24%
2355
16th to endNight
18%14%6%10%8%35%34420%
2577
December1st to 15thNight
18%17%6%10%11%5%443313%
2700
16th to endNight
17%15%7%12%10%6%6%5%3310%
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
73%411%8%2
1296
16th to endDay
69%6%9%10%3
1536
February1st to 15thDay
70%6%11%7%3
1521
16th to endDay
72%46%11%4
1531
March1st to 15thDay
65%47%14%7%
1861
16th to endDay
61%47%17%8%1
2112
April1st to 15thDay
63%38%15%7%2
2230
16th to endDay
56%28%17%12%1
2340
May1st to 15thDay
57%310%17%10%
2370
16th to endDay
59%310%18%7%
2809
June1st to 15thDay
56%6%11%15%9%
2700
16th to endDay
60%6%11%15%6%
2700
July1st to 15thDay
52%417%18%6%
2541
16th to endDay
55%5%13%17%6%
2540
August1st to 15thDay
55%5%18%17%3
2379
16th to endDay
49%5%20%19%4
2483
September1st to 15thDay
49%415%22%7%
2097
16th to endDay
45%5%15%23%9%
1873
October1st to 15thDay
58%412%16%7%
1708
16th to endDay
66%5%11%11%4
1601
November1st to 15thDay
65%5%9%14%5%
1503
16th to endDay
72%310%11%2
1380
December1st to 15thDay
79%48%6%1
1260
16th to endDay
78%47%7%2
1344
January1st to 15thNight
74%5%8%8%2
2640
16th to endNight
68%5%8%13%3
2688
February1st to 15thNight
67%311%13%3
2343
16th to endNight
68%5%8%12%5%
1940
March1st to 15thNight
62%49%15%7%
2098
16th to endNight
57%39%19%8%1
2109
April1st to 15thNight
62%27%14%11%2
1719
16th to endNight
52%38%18%14%1
1620
May1st to 15thNight
58%48%17%9%1
1590
16th to endNight
58%6%9%16%8%
1310
June1st to 15thNight
52%5%12%18%9%1
1260
16th to endNight
53%7%12%18%8%
1260
July1st to 15thNight
49%7%16%19%6%
1190
16th to endNight
49%8%15%19%7%
1362
August1st to 15thNight
46%8%18%21%3
1544
16th to endNight
45%8%21%20%4
1719
September1st to 15thNight
45%5%15%23%8%
1860
16th to endNight
42%5%17%23%9%1
1880
October1st to 15thNight
48%414%23%8%
1922
16th to endNight
62%413%15%3
2271
November1st to 15thNight
62%411%14%6%
2355
16th to endNight
67%413%10%2
2577
December1st to 15thNight
76%5%9%7%
2700
16th to endNight
77%5%7%7%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
25%26%38%8%1
60
16th to endDay
17%20%42%12%7%
64
February1st to 15thDay
20%16%37%20%5%
179
16th to endDay
25%23%30%9%7%2
231
March1st to 15thDay
29%22%26%15%32
270
16th to endDay
24%22%23%18%9%1
288
April1st to 15thDay
34%17%28%12%5%1
270
16th to endDay
29%19%30%10%8%1
270
May1st to 15thDay
36%12%29%17%5%
300
16th to endDay
32%17%25%16%6%1
519
June1st to 15thDay
32%13%23%20%9%
495
16th to endDay
28%13%28%21%7%1
495
July1st to 15thDay
27%10%30%20%9%2
475
16th to endDay
24%10%35%22%6%
379
August1st to 15thDay
23%10%30%23%9%1
313
16th to endDay
24%11%28%23%11%1
332
September1st to 15thDay
27%10%27%22%7%2
315
16th to endDay
26%14%30%17%6%3
275
October1st to 15thDay
27%17%25%18%8%2
236
16th to endDay
43%14%25%9%6%2
240
November1st to 15thDay
36%17%24%13%7%
235
16th to endDay
31%15%30%13%7%1
180
December1st to 15thDay
31%20%33%8%5%1
60
16th to endDay
43%20%26%7%1
64
January1st to 15thNight
26%23%32%14%2
743
16th to endNight
19%22%35%17%5%
768
February1st to 15thNight
16%22%32%22%6%
704
16th to endNight
26%17%34%16%41
631
March1st to 15thNight
26%18%28%18%6%
720
16th to endNight
21%18%29%21%7%1
768
April1st to 15thNight
32%16%25%16%7%1
641
16th to endNight
29%12%27%22%6%
540
May1st to 15thNight
27%10%28%26%6%
522
16th to endNight
26%13%26%25%7%
375
June1st to 15thNight
23%8%26%30%10%
360
16th to endNight
21%9%27%32%8%
360
July1st to 15thNight
19%7%30%29%11%1
340
16th to endNight
17%7%30%32%11%
376
August1st to 15thNight
19%5%29%29%16%
473
16th to endNight
19%8%31%26%12%1
573
September1st to 15thNight
24%9%29%24%11%1
675
16th to endNight
23%10%31%25%7%
681
October1st to 15thNight
25%15%29%18%8%1
660
16th to endNight
36%16%22%17%6%
704
November1st to 15thNight
32%17%28%16%4
713
16th to endNight
28%17%30%16%6%
750
December1st to 15thNight
30%21%31%13%2
750
16th to endNight
30%19%27%15%5%1
800
Page generated at 2017-09-22 07:35:33. Version ac04

Copyright 2017 A. Danko


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