Sainte-Scholastique
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sainte-Scholastique 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
32%
14635
13%
46859
8%
14603
38%
14603
17%
33506

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
18%
720
8%
2506
5%
716
22%
716
9%
1967
January16th to endNight
22%
768
10%
2688
5%
768
28%
768
11%
2015
February1st to 15thNight
22%
704
9%
2302
4%
701
28%
701
11%
1785
February16th to endNight
24%
631
13%
1901
6%
631
32%
631
15%
1431
March1st to 15thNight
22%
720
13%
2160
8%
720
28%
720
14%
1636
March16th to endNight
34%
768
19%
1992
10%
768
40%
768
24%
1402
April1st to 15thNight
29%
718
16%
1796
5%
718
34%
718
21%
1340
April16th to endNight
29%
631
16%
1711
6%
631
36%
631
21%
1223
May1st to 15thNight
30%
378
15%
1458
12%
378
40%
378
16%
987
May16th to endNight
34%
375
12%
1497
11%
374
44%
374
17%
989
June1st to 15thNight
34%
360
8%
1440
8%
360
41%
360
14%
1017
June16th to endNight
43%
360
8%
1440
11%
360
48%
360
17%
929
July1st to 15thNight
51%
340
13%
1360
18%
340
56%
340
24%
783
July16th to endNight
54%
376
12%
1418
16%
354
56%
354
23%
834
August1st to 15thNight
53%
366
14%
1437
16%
364
57%
364
22%
875
August16th to endNight
54%
755
19%
1901
10%
755
57%
755
35%
1229
September1st to 15thNight
51%
720
14%
1800
7%
720
52%
720
29%
1265
September16th to endNight
50%
673
21%
1840
14%
673
54%
673
31%
1180
October1st to 15thNight
33%
660
18%
1955
10%
660
43%
660
21%
1347
October16th to endNight
26%
704
10%
2249
7%
704
32%
704
14%
1674
November1st to 15thNight
28%
700
16%
2280
10%
700
37%
700
16%
1628
November16th to endNight
23%
720
12%
2520
8%
720
29%
720
11%
1871
December1st to 15thNight
20%
720
8%
2520
4%
720
26%
720
9%
1974
December16th to endNight
14%
768
10%
2688
3%
768
22%
768
8%
2125

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%7%36%5%3445%6%33%
47966
Night
18%9%36%5%34446%33%
47028
Cloud CoverDay
17%7%36%5%345%5%6%33%
47975
Night
17%9%36%5%3445%6%33%
47034
TransparencyDay
50%7%12%19%9%1
47653
Night
51%6%11%18%9%1
46859
SeeingDay
21%8%27%25%13%3
5564
Night
22%8%30%27%10%
14635

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
21%12%47%7%3445%322%
1432
16th to endDay
12%16%47%7%25%446%27%
1536
February1st to 15thDay
13%13%5%8%7%45%5%5%5%24%
1557
16th to endDay
17%13%5%8%5%34445%27%
1572
March1st to 15thDay
17%10%49%7%35%44428%
1790
16th to endDay
17%7%35%5%23345%39%
2229
April1st to 15thDay
22%8%45%5%33435%33%
2152
16th to endDay
20%7%345%34345%37%
2247
May1st to 15thDay
21%7%26%6%35%445%32%
2504
16th to endDay
20%6%25%5%35%46%7%33%
2618
June1st to 15thDay
22%6%26%4345%5%6%31%
2520
16th to endDay
17%6%26%5%36%6%6%9%28%
2520
July1st to 15thDay
12%425%5%46%5%6%8%38%
2520
16th to endDay
12%425%5%35%6%7%9%35%
2654
August1st to 15thDay
12%6%26%6%36%6%6%8%35%
2508
16th to endDay
9%415%425%5%5%9%45%
2292
September1st to 15thDay
15%5%25%5%3445%8%39%
2160
16th to endDay
14%5%25%323337%49%
1866
October1st to 15thDay
21%6%235%2445%6%35%
1672
16th to endDay
23%8%37%7%34445%26%
1623
November1st to 15thDay
16%7%45%6%35%5%47%33%
1578
16th to endDay
23%8%35%445%446%29%
1440
December1st to 15thDay
23%12%5%8%4245%5%5%21%
1440
16th to endDay
25%12%5%7%6%3443422%
1536
January1st to 15thNight
18%14%6%8%6%3445%5%22%
2506
16th to endNight
12%12%5%10%8%35%445%27%
2688
February1st to 15thNight
12%12%5%10%7%46%5%5%6%24%
2300
16th to endNight
16%11%5%7%5%25%45%429%
1901
March1st to 15thNight
18%11%5%7%6%24445%28%
2147
16th to endNight
15%9%35%43334441%
1992
April1st to 15thNight
25%7%44424335%34%
1796
16th to endNight
20%6%45%423347%36%
1711
May1st to 15thNight
22%7%27%43444435%
1458
16th to endNight
20%5%35%5%24347%38%
1495
June1st to 15thNight
23%7%25%43446%6%30%
1440
16th to endNight
16%5%245%26%5%5%8%37%
1440
July1st to 15thNight
10%314435%5%7%10%43%
1440
16th to endNight
10%4245%345%7%10%40%
1514
August1st to 15thNight
11%5%27%43446%9%40%
1447
16th to endNight
12%4144235%5%6%50%
1901
September1st to 15thNight
14%5%25%5%34448%41%
1800
16th to endNight
16%413323446%48%
1840
October1st to 15thNight
18%7%25%42445%5%39%
1955
16th to endNight
24%8%37%434335%30%
2249
November1st to 15thNight
19%7%36%5%35%45%6%34%
2280
16th to endNight
21%11%37%5%34435%29%
2520
December1st to 15thNight
22%13%46%6%25%44425%
2520
16th to endNight
23%15%5%7%5%3433424%
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
21%12%5%8%7%3445%422%
1432
16th to endDay
12%15%47%7%36%447%27%
1536
February1st to 15thDay
13%13%5%8%7%46%45%5%24%
1557
16th to endDay
17%13%5%8%5%335%45%27%
1572
March1st to 15thDay
17%11%49%7%35%34428%
1800
16th to endDay
17%8%35%5%2345%5%38%
2228
April1st to 15thDay
22%7%46%5%23445%33%
2152
16th to endDay
20%7%345%34445%37%
2247
May1st to 15thDay
20%7%36%6%35%45%5%32%
2504
16th to endDay
19%6%35%5%35%45%7%33%
2618
June1st to 15thDay
21%6%36%5%345%5%7%31%
2520
16th to endDay
17%6%25%6%36%6%7%8%29%
2520
July1st to 15thDay
11%425%5%36%5%6%9%37%
2520
16th to endDay
11%426%5%35%6%7%9%35%
2654
August1st to 15thDay
11%6%26%7%35%6%7%8%35%
2508
16th to endDay
9%415%5%25%5%5%8%45%
2292
September1st to 15thDay
14%5%25%4345%5%8%39%
2160
16th to endDay
13%5%25%413347%48%
1866
October1st to 15thDay
21%7%245%3445%6%34%
1672
16th to endDay
22%8%47%7%35%445%26%
1623
November1st to 15thDay
15%8%46%6%35%5%5%8%32%
1578
16th to endDay
23%7%35%5%44445%30%
1440
December1st to 15thDay
23%12%48%4345%5%421%
1440
16th to endDay
25%12%5%7%6%3343422%
1536
January1st to 15thNight
17%14%6%8%6%34445%22%
2506
16th to endNight
12%11%6%10%7%35%445%27%
2688
February1st to 15thNight
12%12%5%10%6%46%5%5%5%24%
2293
16th to endNight
15%12%5%8%5%25%45%5%28%
1901
March1st to 15thNight
19%10%5%6%5%25%445%28%
2160
16th to endNight
15%10%36%43334440%
1992
April1st to 15thNight
24%7%445%24336%33%
1796
16th to endNight
20%7%26%423346%36%
1711
May1st to 15thNight
21%6%37%5%34445%34%
1458
16th to endNight
20%5%35%5%2435%6%37%
1495
June1st to 15thNight
23%7%25%435%46%6%29%
1440
16th to endNight
16%5%25%5%35%5%6%8%36%
1440
July1st to 15thNight
9%4235%35%5%6%10%43%
1440
16th to endNight
10%4345%345%7%10%41%
1514
August1st to 15thNight
10%6%26%5%245%6%9%40%
1447
16th to endNight
11%41442445%7%49%
1901
September1st to 15thNight
13%5%25%5%345%48%41%
1800
16th to endNight
15%41432335%6%48%
1840
October1st to 15thNight
18%6%25%42445%6%38%
1955
16th to endNight
23%8%47%5%33345%30%
2249
November1st to 15thNight
19%6%37%5%25%45%6%33%
2280
16th to endNight
21%11%37%6%335%4429%
2520
December1st to 15thNight
22%12%5%6%5%35%44424%
2520
16th to endNight
23%16%5%7%5%3433423%
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
64%6%9%13%5%
1433
16th to endDay
56%7%12%14%8%
1536
February1st to 15thDay
61%5%11%17%3
1559
16th to endDay
59%5%10%14%8%1
1572
March1st to 15thDay
59%5%11%14%8%1
1800
16th to endDay
48%410%17%14%4
2229
April1st to 15thDay
53%48%19%11%2
2152
16th to endDay
49%48%19%14%4
2247
May1st to 15thDay
52%5%9%16%13%2
2504
16th to endDay
48%7%11%19%11%1
2622
June1st to 15thDay
51%7%11%18%10%
2520
16th to endDay
48%9%12%18%8%1
2520
July1st to 15thDay
38%9%15%24%11%
2371
16th to endDay
41%10%18%21%8%
2487
August1st to 15thDay
43%10%17%20%7%
2494
16th to endDay
32%8%18%27%11%
2292
September1st to 15thDay
41%6%15%24%12%
2160
16th to endDay
37%5%12%32%10%
1866
October1st to 15thDay
50%5%11%22%10%
1672
16th to endDay
58%6%13%14%6%
1623
November1st to 15thDay
49%7%15%18%8%
1578
16th to endDay
55%7%11%17%6%
1440
December1st to 15thDay
64%7%12%11%2
1440
16th to endDay
65%6%10%10%6%
1536
January1st to 15thNight
62%6%11%14%4
2506
16th to endNight
59%6%11%14%7%1
2688
February1st to 15thNight
59%8%11%15%4
2302
16th to endNight
56%6%10%16%10%
1901
March1st to 15thNight
58%5%10%16%8%1
2160
16th to endNight
47%5%9%19%15%3
1992
April1st to 15thNight
53%37%18%14%1
1796
16th to endNight
49%5%7%17%15%3
1711
May1st to 15thNight
51%5%8%16%14%4
1458
16th to endNight
47%7%10%19%13%1
1497
June1st to 15thNight
52%7%11%18%9%
1440
16th to endNight
43%9%12%18%14%
1440
July1st to 15thNight
33%9%14%26%15%
1360
16th to endNight
36%8%18%23%12%
1418
August1st to 15thNight
38%8%19%22%10%
1437
16th to endNight
34%7%16%28%12%
1901
September1st to 15thNight
42%7%12%23%13%
1800
16th to endNight
37%5%11%32%12%
1840
October1st to 15thNight
46%6%10%23%11%
1955
16th to endNight
56%6%12%17%7%
2249
November1st to 15thNight
51%6%13%17%8%2
2280
16th to endNight
57%6%12%17%5%
2520
December1st to 15thNight
62%7%12%14%3
2520
16th to endNight
65%5%10%12%6%
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
15%25%23%30%5%1
60
16th to endDay
28%14%31%18%6%1
64
February1st to 15thDay
32%20%31%14%1
87
16th to endDay
27%7%33%26%4
231
March1st to 15thDay
21%14%31%27%5%
270
16th to endDay
24%7%31%22%10%2
288
April1st to 15thDay
30%12%27%18%7%2
270
16th to endDay
21%11%28%22%12%2
270
May1st to 15thDay
28%7%28%19%12%3
288
16th to endDay
21%10%32%20%12%2
331
June1st to 15thDay
25%8%27%26%10%1
315
16th to endDay
21%5%24%33%14%1
315
July1st to 15thDay
14%428%30%16%5%
305
16th to endDay
14%219%38%20%4
326
August1st to 15thDay
14%419%36%20%5%
313
16th to endDay
9%325%28%19%12%
332
September1st to 15thDay
14%7%21%26%19%10%
315
16th to endDay
17%8%24%17%21%10%
266
October1st to 15thDay
21%8%24%26%17%1
255
16th to endDay
29%11%28%20%10%
247
November1st to 15thDay
22%9%33%22%10%1
232
16th to endDay
35%8%25%25%6%
60
December1st to 15thDay
28%8%30%26%6%
60
16th to endDay
37%15%35%10%
64
January1st to 15thNight
24%14%32%24%4
720
16th to endNight
18%13%37%22%7%
768
February1st to 15thNight
19%10%37%25%6%
704
16th to endNight
22%8%36%26%5%
631
March1st to 15thNight
25%11%34%25%3
720
16th to endNight
20%7%31%30%8%
768
April1st to 15thNight
26%9%27%31%4
718
16th to endNight
25%10%30%24%9%
631
May1st to 15thNight
24%333%27%8%1
378
16th to endNight
21%5%33%30%8%
375
June1st to 15thNight
28%426%31%8%
360
16th to endNight
18%229%34%13%
360
July1st to 15thNight
9%329%35%20%
340
16th to endNight
11%125%43%16%1
376
August1st to 15thNight
14%319%40%20%2
366
16th to endNight
13%323%33%24%1
755
September1st to 15thNight
17%321%40%15%1
720
16th to endNight
18%425%26%23%2
673
October1st to 15thNight
21%6%30%28%11%
660
16th to endNight
28%8%30%25%5%
704
November1st to 15thNight
24%10%30%24%9%
700
16th to endNight
26%13%29%18%10%
720
December1st to 15thNight
31%12%29%22%4
720
16th to endNight
32%11%33%18%3
768
Page generated at 2017-09-20 04:49:57. Version ac04

Copyright 2017 A. Danko


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