Saint-Hyacinthe
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Saint-Hyacinthe clear sky chart from 2005-11-05 to

2017-09-12
.

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
31%
14610
12%
46784
8%
14578
36%
14578
15%
34414

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
20%
720
8%
2506
5%
716
24%
716
8%
2058
January16th to endNight
21%
768
9%
2688
6%
768
26%
768
9%
2120
February1st to 15thNight
20%
704
7%
2317
4%
701
25%
701
10%
1863
February16th to endNight
23%
631
10%
1893
7%
631
29%
631
11%
1498
March1st to 15thNight
28%
720
14%
2160
11%
720
33%
720
14%
1652
March16th to endNight
33%
768
18%
2007
9%
768
39%
768
21%
1457
April1st to 15thNight
28%
718
14%
1796
5%
718
33%
718
17%
1406
April16th to endNight
29%
599
16%
1679
6%
599
36%
599
21%
1187
May1st to 15thNight
30%
423
16%
1503
14%
423
38%
423
17%
1030
May16th to endNight
34%
375
11%
1497
11%
374
42%
374
16%
998
June1st to 15thNight
33%
360
8%
1440
8%
360
39%
360
12%
1020
June16th to endNight
45%
360
8%
1440
11%
360
49%
360
18%
931
July1st to 15thNight
50%
340
11%
1360
17%
340
54%
340
21%
835
July16th to endNight
53%
376
12%
1418
16%
354
57%
354
22%
874
August1st to 15thNight
54%
386
14%
1457
14%
384
55%
384
20%
934
August16th to endNight
52%
726
18%
1872
11%
726
54%
726
33%
1230
September1st to 15thNight
46%
707
13%
1776
7%
707
47%
707
28%
1237
September16th to endNight
45%
657
19%
1815
13%
657
49%
657
29%
1183
October1st to 15thNight
33%
660
18%
1917
11%
660
42%
660
20%
1368
October16th to endNight
25%
704
10%
2277
7%
704
31%
704
13%
1734
November1st to 15thNight
27%
700
16%
2277
11%
700
35%
700
15%
1671
November16th to endNight
24%
720
12%
2481
9%
720
29%
720
11%
1898
December1st to 15thNight
17%
720
7%
2520
3%
720
22%
720
7%
2042
December16th to endNight
13%
768
9%
2688
3%
768
20%
768
7%
2188

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
19%8%36%5%34446%32%
47888
Night
20%10%46%5%34445%30%
46954
Cloud CoverDay
19%9%36%5%3445%6%31%
47898
Night
20%10%47%5%24345%30%
46959
TransparencyDay
52%7%11%19%8%
47576
Night
55%6%10%18%9%1
46784
SeeingDay
23%9%26%24%12%3
5597
Night
25%8%26%27%10%
14610

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
24%15%5%9%6%3433320%
1432
16th to endDay
15%15%5%8%5%35%5%45%25%
1536
February1st to 15thDay
14%15%6%11%5%45%44422%
1544
16th to endDay
18%13%5%9%5%34345%25%
1580
March1st to 15thDay
18%11%46%6%35%345%28%
1790
16th to endDay
19%8%36%5%24345%36%
2217
April1st to 15thDay
23%9%36%5%23435%31%
2152
16th to endDay
22%6%25%424446%36%
2280
May1st to 15thDay
21%6%36%5%3445%6%32%
2459
16th to endDay
20%5%26%5%35%5%5%6%32%
2618
June1st to 15thDay
25%5%25%425%45%7%31%
2520
16th to endDay
19%6%35%435%5%6%8%31%
2520
July1st to 15thDay
13%5%25%6%35%46%9%36%
2520
16th to endDay
13%425%5%35%5%6%9%36%
2654
August1st to 15thDay
14%6%26%6%35%5%6%8%33%
2481
16th to endDay
12%5%14425%45%8%45%
2327
September1st to 15thDay
17%6%244245%46%40%
2103
16th to endDay
17%414423346%45%
1815
October1st to 15thDay
23%7%26%5%2445%6%32%
1712
16th to endDay
24%10%35%6%34445%26%
1594
November1st to 15thDay
19%9%35%5%3445%6%31%
1581
16th to endDay
24%11%35%424435%29%
1477
December1st to 15thDay
27%13%5%7%6%34445%18%
1440
16th to endDay
27%16%6%7%5%2422420%
1536
January1st to 15thNight
21%15%6%9%6%3443420%
2506
16th to endNight
14%15%6%8%7%45%44422%
2688
February1st to 15thNight
15%14%7%10%8%44345%20%
2316
16th to endNight
17%13%7%8%6%3444425%
1893
March1st to 15thNight
22%12%47%5%2334428%
2147
16th to endNight
17%12%45%5%2333436%
2007
April1st to 15thNight
27%8%36%5%2433429%
1796
16th to endNight
23%7%24332346%36%
1679
May1st to 15thNight
23%7%26%424436%34%
1503
16th to endNight
22%5%3442445%7%34%
1495
June1st to 15thNight
27%7%3442345%6%28%
1440
16th to endNight
16%5%35%5%245%6%8%35%
1440
July1st to 15thNight
14%425%5%35%48%9%36%
1440
16th to endNight
12%3345%45%5%6%8%39%
1514
August1st to 15thNight
14%6%25%4345%6%8%37%
1467
16th to endNight
12%5%15%5%3345%8%44%
1872
September1st to 15thNight
19%5%25%324446%40%
1776
16th to endNight
19%414323347%45%
1815
October1st to 15thNight
19%6%37%423445%37%
1917
16th to endNight
28%8%36%5%33235%28%
2277
November1st to 15thNight
20%11%35%5%345%4430%
2277
16th to endNight
25%12%46%5%2333327%
2481
December1st to 15thNight
25%15%5%7%6%2332421%
2520
16th to endNight
24%18%6%6%5%3322321%
2688

Percentage Cloud Cover SE (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
23%16%5%10%6%3343317%
1432
16th to endDay
14%15%5%9%6%445%46%22%
1536
February1st to 15thDay
14%16%6%10%7%36%44420%
1544
16th to endDay
17%14%5%9%6%25%345%24%
1580
March1st to 15thDay
18%12%5%7%7%3444427%
1800
16th to endDay
18%9%46%5%33445%35%
2217
April1st to 15thDay
23%11%36%5%23335%30%
2152
16th to endDay
22%8%34434345%35%
2280
May1st to 15thDay
21%6%36%5%2445%6%32%
2459
16th to endDay
20%6%35%5%25%5%5%7%31%
2618
June1st to 15thDay
25%6%25%42435%7%30%
2520
16th to endDay
19%6%26%5%25%5%5%8%30%
2520
July1st to 15thDay
13%5%35%5%45%5%6%8%36%
2520
16th to endDay
14%6%25%5%35%5%7%8%35%
2654
August1st to 15thDay
14%6%26%7%36%5%6%8%32%
2481
16th to endDay
12%424425%45%8%44%
2327
September1st to 15thDay
17%6%25%5%2345%7%39%
2103
16th to endDay
16%6%24324446%44%
1815
October1st to 15thDay
22%8%35%42445%6%31%
1712
16th to endDay
25%10%36%5%34446%25%
1594
November1st to 15thDay
19%10%36%5%25%5%5%5%31%
1581
16th to endDay
23%12%45%433346%27%
1477
December1st to 15thDay
26%14%5%8%7%33435%16%
1440
16th to endDay
26%17%5%7%6%2433317%
1536
January1st to 15thNight
20%15%7%9%6%34435%19%
2506
16th to endNight
15%15%6%10%6%45%445%21%
2688
February1st to 15thNight
15%14%7%12%8%35%345%19%
2309
16th to endNight
17%13%7%9%7%3433425%
1893
March1st to 15thNight
21%13%5%7%5%3333428%
2160
16th to endNight
17%12%46%42333436%
2006
April1st to 15thNight
26%9%36%5%2344427%
1796
16th to endNight
22%8%24333345%37%
1679
May1st to 15thNight
22%8%246%23345%34%
1503
16th to endNight
22%6%25%43445%7%33%
1495
June1st to 15thNight
28%6%26%32335%7%27%
1440
16th to endNight
16%5%25%4245%7%8%35%
1440
July1st to 15thNight
13%5%25%5%35%5%6%9%36%
1440
16th to endNight
12%425%5%37%5%7%8%39%
1514
August1st to 15thNight
13%6%26%425%46%8%37%
1467
16th to endNight
13%4245%2445%8%44%
1872
September1st to 15thNight
19%6%25%324346%40%
1776
16th to endNight
19%414413346%45%
1815
October1st to 15thNight
18%9%26%5%24445%35%
1917
16th to endNight
28%9%46%5%22335%27%
2277
November1st to 15thNight
20%11%35%5%35%445%29%
2277
16th to endNight
25%13%47%5%2434326%
2481
December1st to 15thNight
26%16%6%7%6%2323419%
2520
16th to endNight
24%19%6%7%6%2322320%
2688

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
69%6%7%11%4
1433
16th to endDay
59%9%11%14%5%
1536
February1st to 15thDay
65%6%9%16%2
1547
16th to endDay
61%5%10%13%7%1
1580
March1st to 15thDay
59%5%12%14%6%1
1800
16th to endDay
49%6%11%19%11%2
2217
April1st to 15thDay
56%47%18%10%1
2152
16th to endDay
49%5%9%19%12%3
2280
May1st to 15thDay
51%6%10%18%12%
2459
16th to endDay
49%7%11%18%10%1
2622
June1st to 15thDay
51%7%11%18%9%
2520
16th to endDay
49%8%12%21%7%
2520
July1st to 15thDay
40%10%14%25%9%
2371
16th to endDay
44%9%17%22%7%
2487
August1st to 15thDay
47%9%14%22%5%
2467
16th to endDay
35%7%17%27%10%
2327
September1st to 15thDay
42%8%12%24%11%
2103
16th to endDay
39%6%12%30%11%
1815
October1st to 15thDay
51%7%13%20%7%
1712
16th to endDay
58%7%12%16%5%
1594
November1st to 15thDay
51%8%11%18%8%
1581
16th to endDay
57%7%10%15%7%
1477
December1st to 15thDay
68%7%11%11%1
1440
16th to endDay
70%6%9%7%6%
1536
January1st to 15thNight
67%7%8%12%4
2506
16th to endNight
63%6%8%14%6%
2688
February1st to 15thNight
66%5%9%13%4
2317
16th to endNight
62%6%8%13%9%
1893
March1st to 15thNight
60%48%16%8%1
2160
16th to endNight
51%48%17%14%3
2007
April1st to 15thNight
58%5%417%12%1
1796
16th to endNight
48%5%9%18%15%3
1679
May1st to 15thNight
50%5%7%17%15%4
1503
16th to endNight
48%7%11%20%10%2
1497
June1st to 15thNight
55%5%9%19%8%1
1440
16th to endNight
44%8%12%19%13%
1440
July1st to 15thNight
39%8%13%25%12%
1360
16th to endNight
39%8%16%23%11%
1418
August1st to 15thNight
41%9%16%23%9%
1457
16th to endNight
37%6%15%28%10%
1872
September1st to 15thNight
43%6%12%25%12%
1776
16th to endNight
39%6%10%29%13%
1815
October1st to 15thNight
48%7%10%23%10%
1917
16th to endNight
60%410%17%6%
2277
November1st to 15thNight
54%6%12%17%6%2
2277
16th to endNight
61%5%9%16%7%
2481
December1st to 15thNight
68%5%10%13%2
2520
16th to endNight
69%49%10%5%
2688

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%16%26%26%10%
60
16th to endDay
37%9%28%18%41
64
February1st to 15thDay
33%16%21%21%5%
106
16th to endDay
25%13%29%25%5%
239
March1st to 15thDay
26%11%30%24%5%
270
16th to endDay
23%9%29%24%9%3
288
April1st to 15thDay
30%11%27%21%7%2
270
16th to endDay
24%12%27%18%11%4
270
May1st to 15thDay
29%8%29%17%11%4
288
16th to endDay
19%12%31%22%12%2
331
June1st to 15thDay
31%9%20%27%8%3
315
16th to endDay
20%6%32%27%11%1
315
July1st to 15thDay
17%6%28%27%15%4
305
16th to endDay
17%321%38%17%2
326
August1st to 15thDay
18%423%29%16%6%
313
16th to endDay
15%5%21%25%19%12%
332
September1st to 15thDay
19%5%22%27%16%9%
299
16th to endDay
18%7%26%23%13%9%
254
October1st to 15thDay
24%8%27%20%15%3
255
16th to endDay
31%11%24%19%13%
241
November1st to 15thDay
28%10%27%20%11%1
235
16th to endDay
28%15%18%23%12%1
97
December1st to 15thDay
35%11%21%26%13
60
16th to endDay
39%15%31%14%
64
January1st to 15thNight
27%13%28%23%7%
720
16th to endNight
24%11%32%23%8%
768
February1st to 15thNight
23%10%33%26%6%
704
16th to endNight
24%10%30%27%5%
631
March1st to 15thNight
28%9%27%29%5%
720
16th to endNight
23%9%27%29%9%1
768
April1st to 15thNight
29%10%26%27%6%
718
16th to endNight
27%10%27%24%9%
599
May1st to 15thNight
26%6%32%24%9%1
423
16th to endNight
25%7%25%33%8%
375
June1st to 15thNight
32%423%28%10%
360
16th to endNight
17%428%37%11%
360
July1st to 15thNight
14%424%37%18%1
340
16th to endNight
13%322%43%16%
376
August1st to 15thNight
17%317%36%23%1
386
16th to endNight
16%321%35%21%2
726
September1st to 15thNight
21%323%33%16%1
707
16th to endNight
21%5%23%29%17%2
657
October1st to 15thNight
22%8%29%25%12%
660
16th to endNight
33%10%25%23%6%
704
November1st to 15thNight
27%10%29%22%9%
700
16th to endNight
32%13%24%19%8%1
720
December1st to 15thNight
34%11%25%21%5%
720
16th to endNight
35%11%26%20%41
768
Page generated at 2017-09-13 07:39:24. Version ac04

Copyright 2017 A. Danko


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