Chisasibi
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chisasibi clear sky chart from 2005-11-06 to 2024-01-13.

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%
23518
6%
75054
5%
23469
35%
23469
10%
61340

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 10thNight
26%
951
3%
2845
1%
949
27%
949
4%
2589
January11th to 20thNight
38%
911
5%
2731
4%
911
40%
911
8%
2347
January21st to endNight
43%
990
8%
2970
8%
990
44%
990
8%
2559
February1st to 10thNight
44%
792
6%
2485
6%
792
46%
792
8%
2093
February11th to 20thNight
46%
703
10%
2275
10%
700
48%
700
12%
1779
February21st to endNight
46%
592
12%
1924
11%
592
48%
592
14%
1432
March1st to 10thNight
47%
720
12%
2153
12%
720
49%
720
15%
1650
March11th to 20thNight
38%
720
11%
1980
7%
720
42%
720
16%
1536
March21st to endNight
40%
792
13%
2130
8%
792
42%
792
18%
1621
April1st to 10thNight
39%
689
12%
1769
7%
689
41%
689
17%
1389
April11th to 20thNight
45%
533
16%
1597
13%
533
49%
533
22%
1106
April21st to endNight
46%
414
14%
1494
16%
414
49%
414
19%
1002
May1st to 10thNight
39%
360
10%
1440
13%
360
43%
360
16%
971
May11th to 20thNight
37%
354
5%
1267
3%
354
37%
354
15%
894
May21st to endNight
34%
388
0%
1304
0%
388
34%
388
16%
937
June1st to 10thNight
42%
360
0%
1080
0%
360
42%
360
24%
724
June11th to 20thNight
45%
360
0%
1080
0%
360
45%
360
28%
677
June21st to endNight
43%
360
0%
1080
0%
360
43%
360
23%
735
July1st to 10thNight
48%
350
0%
1107
0%
350
48%
350
19%
773
July11th to 20thNight
39%
348
0%
1218
0%
348
39%
348
15%
873
July21st to endNight
42%
394
2%
1301
1%
372
43%
372
12%
986
August1st to 10thNight
43%
358
5%
1320
7%
356
44%
356
12%
980
August11th to 20thNight
41%
439
7%
1503
9%
439
42%
439
13%
1121
August21st to endNight
43%
594
11%
1782
10%
594
45%
594
19%
1299
September1st to 10thNight
29%
683
7%
1763
3%
683
30%
683
14%
1412
September11th to 20thNight
33%
720
8%
1826
4%
720
35%
720
14%
1484
September21st to endNight
30%
720
8%
2060
5%
720
31%
720
14%
1637
October1st to 10thNight
24%
720
7%
2160
5%
720
27%
720
9%
1776
October11th to 20thNight
20%
720
6%
2160
4%
720
23%
720
7%
1848
October21st to endNight
24%
792
4%
2735
4%
792
26%
792
6%
2367
November1st to 10thNight
13%
740
3%
2592
3%
740
14%
740
3%
2359
November11th to 20thNight
13%
760
2%
2660
1%
760
13%
760
2%
2452
November21st to endNight
19%
977
5%
2937
3%
977
20%
977
4%
2688
December1st to 10thNight
14%
1040
2%
3040
1%
1040
15%
1040
3%
2861
December11th to 20thNight
26%
1039
5%
3730
3%
1038
27%
1038
4%
3319
December21st to endNight
29%
1135
3%
5556
4%
1116
30%
1116
3%
5064

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
16%12%5%9%8%46%6%5%6%22%
74472
Night
15%14%6%11%9%5%7%6%5%5%17%
75271
TransparencyDay
61%6%11%16%6%
74153
Night
67%6%9%13%5%
75126
SeeingDay
21%7%24%28%15%5%
14925
Night
21%7%23%31%16%3
23531

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 10thDay
12%16%7%16%12%8%9%8%7%33
1318
11th to 20thDay
7%12%7%12%12%8%12%10%9%46%
1274
21st to endDay
6%10%5%12%12%9%13%13%10%47%
1386
February1st to 10thDay
5%9%6%11%11%7%13%16%12%47%
1472
11th to 20thDay
6%12%5%11%11%6%11%14%12%5%8%
1573
21st to endDay
411%49%8%5%10%14%9%9%17%
1332
March1st to 10thDay
8%10%6%11%11%6%10%11%8%6%12%
1800
11th to 20thDay
7%11%5%11%11%5%8%11%6%6%18%
1980
21st to endDay
10%10%5%8%8%6%10%8%5%5%24%
2225
April1st to 10thDay
12%14%5%10%9%5%8%445%24%
2207
11th to 20thDay
9%11%6%10%8%5%5%5%36%32%
2312
21st to endDay
13%11%49%10%34446%31%
2466
May1st to 10thDay
15%11%7%13%8%345%36%26%
2520
11th to 20thDay
15%8%6%10%7%3445%7%28%
2625
21st to endDay
14%10%6%9%6%46%5%7%8%25%
2971
June1st to 10thDay
15%9%36%5%35%45%8%37%
2880
11th to 20thDay
14%6%35%6%35%5%5%8%40%
2880
21st to endDay
15%9%46%42445%8%38%
2880
July1st to 10thDay
16%9%47%7%35%5%7%8%30%
2817
11th to 20thDay
19%10%36%5%345%6%8%31%
2700
21st to endDay
21%12%48%6%45%5%5%7%24%
2940
August1st to 10thDay
24%11%47%5%345%6%7%24%
2610
11th to 20thDay
22%12%37%5%35%5%5%7%27%
2396
21st to endDay
19%9%37%5%445%6%8%30%
2574
September1st to 10thDay
26%11%47%6%3445%8%22%
2178
11th to 20thDay
25%13%5%8%7%35%445%20%
2133
21st to endDay
26%14%47%7%34445%21%
1900
October1st to 10thDay
26%15%48%6%35%445%20%
1800
11th to 20thDay
28%21%5%9%7%3343413%
1800
21st to endDay
23%22%7%11%7%5%5%43410%
1618
November1st to 10thDay
20%26%9%12%7%45%3447%
1486
11th to 20thDay
22%23%9%15%9%333337%
1520
21st to endDay
13%20%9%21%11%443439%
1236
December1st to 10thDay
9%21%10%17%16%6%35%337%
1140
11th to 20thDay
8%16%8%14%16%8%9%5%3211%
1433
21st to endDay
9%21%8%14%16%6%7%5%446%
2090
January1st to 10thNight
13%15%7%16%13%7%9%9%6%24
2845
11th to 20thNight
9%13%7%12%11%6%12%11%10%37%
2731
21st to endNight
6%10%6%12%15%8%12%13%8%38%
2970
February1st to 10thNight
39%6%13%12%7%15%14%12%5%4
2485
11th to 20thNight
6%10%5%11%10%5%11%13%14%5%10%
2273
21st to endNight
412%6%9%9%5%9%12%10%10%15%
1924
March1st to 10thNight
6%9%411%9%6%9%12%10%6%19%
2143
11th to 20thNight
7%10%5%10%9%6%9%9%7%8%21%
1979
21st to endNight
10%10%48%8%5%10%8%5%7%25%
2130
April1st to 10thNight
15%12%410%7%47%5%5%6%25%
1769
11th to 20thNight
9%10%5%8%8%45%5%5%7%35%
1597
21st to endNight
13%10%5%8%6%4445%7%35%
1494
May1st to 10thNight
17%10%5%8%6%34447%33%
1440
11th to 20thNight
17%9%410%6%45%5%5%8%27%
1267
21st to endNight
16%11%5%10%6%345%7%6%29%
1303
June1st to 10thNight
17%8%36%5%35%5%5%6%38%
1080
11th to 20thNight
15%6%35%435%46%7%42%
1080
21st to endNight
15%8%38%5%445%46%38%
1080
July1st to 10thNight
17%9%36%5%36%5%6%9%30%
1140
11th to 20thNight
18%10%47%8%446%5%7%28%
1260
21st to endNight
21%13%5%8%6%345%5%7%23%
1378
August1st to 10thNight
23%12%36%6%35%5%5%5%26%
1328
11th to 20thNight
22%11%5%8%5%345%46%28%
1503
21st to endNight
18%11%37%6%25%45%9%31%
1782
September1st to 10thNight
26%11%48%6%345%5%5%24%
1763
11th to 20thNight
23%13%47%6%45%5%5%6%23%
1826
21st to endNight
22%13%5%8%6%35%447%23%
2060
October1st to 10thNight
25%16%49%6%45%435%19%
2160
11th to 20thNight
26%21%49%7%34435%15%
2160
21st to endNight
23%20%7%11%7%34445%13%
2735
November1st to 10thNight
24%26%8%13%6%333238%
2592
11th to 20thNight
23%23%10%15%7%343337%
2660
21st to endNight
14%22%11%17%9%45%3338%
2937
December1st to 10thNight
12%19%11%21%14%6%43226%
3040
11th to 20thNight
10%15%8%17%16%7%8%42212%
3769
21st to endNight
10%20%6%14%18%7%7%5%336%
5588

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 10thDay
80%7%7%5%1
1319
11th to 20thDay
73%6%7%11%3
1274
21st to endDay
70%7%6%10%6%
1386
February1st to 10thDay
65%9%8%12%5%
1472
11th to 20thDay
65%8%10%13%5%
1582
21st to endDay
57%6%16%16%6%
1332
March1st to 10thDay
66%7%8%15%4
1803
11th to 20thDay
61%5%9%16%7%
1980
21st to endDay
61%5%12%15%7%
2225
April1st to 10thDay
64%36%17%9%1
2207
11th to 20thDay
54%49%22%11%
2312
21st to endDay
56%39%19%12%1
2466
May1st to 10thDay
60%48%22%6%
2520
11th to 20thDay
55%6%10%23%7%
2629
21st to endDay
54%7%11%20%7%
2971
June1st to 10thDay
45%5%10%26%12%1
2880
11th to 20thDay
44%5%10%26%15%1
2880
21st to endDay
45%5%13%24%12%1
2880
July1st to 10thDay
50%8%14%21%7%
2741
11th to 20thDay
48%8%17%22%5%
2619
21st to endDay
58%8%16%15%21
2777
August1st to 10thDay
58%8%18%13%2
2594
11th to 20thDay
58%6%16%16%4
2396
21st to endDay
52%7%17%20%5%
2574
September1st to 10thDay
62%7%14%14%3
2178
11th to 20thDay
66%6%12%14%2
2133
21st to endDay
67%6%12%12%3
1900
October1st to 10thDay
66%6%14%12%2
1800
11th to 20thDay
76%6%10%8%1
1800
21st to endDay
77%7%7%7%1
1618
November1st to 10thDay
82%6%6%5%1
1486
11th to 20thDay
83%5%6%42
1520
21st to endDay
81%5%7%7%1
1236
December1st to 10thDay
85%45%5%1
1140
11th to 20thDay
79%6%6%6%2
1433
21st to endDay
81%5%5%6%2
2090
January1st to 10thNight
80%6%7%5%1
2845
11th to 20thNight
72%7%8%10%3
2731
21st to endNight
71%8%6%11%5%
2970
February1st to 10thNight
68%9%6%11%5%
2485
11th to 20thNight
61%7%11%15%6%
2275
21st to endNight
56%7%13%17%7%
1924
March1st to 10thNight
57%8%9%20%7%
2153
11th to 20thNight
58%6%10%15%10%
1980
21st to endNight
56%5%11%18%9%
2130
April1st to 10thNight
60%5%8%16%11%1
1769
11th to 20thNight
49%410%23%13%1
1597
21st to endNight
49%49%20%16%
1494
May1st to 10thNight
52%48%23%11%2
1440
11th to 20thNight
54%5%10%21%9%1
1268
21st to endNight
54%6%9%21%10%1
1304
June1st to 10thNight
46%5%8%26%14%1
1080
11th to 20thNight
40%5%11%26%19%
1080
21st to endNight
47%6%11%22%14%1
1080
July1st to 10thNight
47%9%12%25%7%
1107
11th to 20thNight
53%8%15%20%4
1218
21st to endNight
60%6%15%16%3
1301
August1st to 10thNight
58%6%16%17%3
1320
11th to 20thNight
58%7%14%15%6%
1503
21st to endNight
53%6%15%21%5%
1782
September1st to 10thNight
62%6%16%14%2
1763
11th to 20thNight
61%8%15%14%2
1826
21st to endNight
63%5%14%14%4
2060
October1st to 10thNight
68%6%13%11%2
2160
11th to 20thNight
73%5%10%9%3
2160
21st to endNight
74%7%10%7%21
2735
November1st to 10thNight
82%5%6%6%1
2592
11th to 20thNight
84%5%5%41
2660
21st to endNight
81%6%5%7%1
2937
December1st to 10thNight
87%3441
3040
11th to 20thNight
78%6%6%8%3
3769
21st to endNight
81%7%5%6%2
5588

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 10thDay
12%6%26%34%16%6%
180
11th to 20thDay
10%7%27%29%23%5%
164
21st to endDay
13%6%19%32%23%8%
176
February1st to 10thDay
7%424%37%20%8%
206
11th to 20thDay
10%431%32%19%5%
240
21st to endDay
9%7%29%32%16%7%
198
March1st to 10thDay
12%6%24%28%15%15%
354
11th to 20thDay
10%8%29%30%16%7%
420
21st to endDay
15%5%27%32%16%5%
462
April1st to 10thDay
14%6%18%35%20%7%
420
11th to 20thDay
14%6%25%26%21%8%
412
21st to endDay
18%6%23%26%17%10%
420
May1st to 10thDay
17%7%22%27%21%6%
423
11th to 20thDay
18%8%27%29%15%3
594
21st to endDay
19%10%30%28%11%3
731
June1st to 10thDay
18%6%26%29%16%5%
810
11th to 20thDay
18%6%28%29%14%5%
810
21st to endDay
20%7%22%32%14%5%
810
July1st to 10thDay
19%6%25%31%16%4
736
11th to 20thDay
21%5%25%30%15%3
618
21st to endDay
27%419%28%16%6%
684
August1st to 10thDay
30%5%17%27%14%6%
550
11th to 20thDay
29%7%15%24%17%8%
439
21st to endDay
23%7%21%27%15%7%
495
September1st to 10thDay
33%8%25%21%10%3
450
11th to 20thDay
27%11%27%20%12%3
450
21st to endDay
35%8%25%17%10%4
450
October1st to 10thDay
32%10%26%20%9%3
450
11th to 20thDay
38%6%26%17%10%4
450
21st to endDay
24%11%20%26%13%5%
225
November1st to 10thDay
29%13%22%22%11%4
180
11th to 20thDay
27%14%19%22%13%4
180
21st to endDay
21%7%23%27%17%6%
180
December1st to 10thDay
17%8%24%31%18%2
180
11th to 20thDay
15%13%24%29%14%4
180
21st to endDay
16%7%27%30%18%3
198
January1st to 10thNight
19%7%24%31%15%4
953
11th to 20thNight
14%6%19%35%21%4
911
21st to endNight
11%417%34%26%8%
990
February1st to 10thNight
7%5%20%38%24%5%
792
11th to 20thNight
10%5%21%37%20%7%
703
21st to endNight
9%421%35%23%8%
592
March1st to 10thNight
11%6%20%36%23%5%
720
11th to 20thNight
12%7%27%35%16%4
720
21st to endNight
14%7%26%31%18%3
792
April1st to 10thNight
19%424%34%16%3
689
11th to 20thNight
13%423%35%21%5%
533
21st to endNight
19%5%21%35%19%1
414
May1st to 10thNight
21%5%24%32%14%3
360
11th to 20thNight
21%8%26%32%12%1
354
21st to endNight
20%8%27%33%11%
389
June1st to 10thNight
20%425%34%16%1
360
11th to 20thNight
19%6%25%34%14%3
360
21st to endNight
18%6%24%36%14%2
360
July1st to 10thNight
19%320%35%21%1
350
11th to 20thNight
20%5%23%37%14%1
348
21st to endNight
23%414%34%22%3
394
August1st to 10thNight
25%5%16%32%20%2
358
11th to 20thNight
28%5%17%30%17%4
439
21st to endNight
25%321%30%18%3
594
September1st to 10thNight
32%7%24%24%12%1
683
11th to 20thNight
30%8%22%29%11%
720
21st to endNight
30%8%23%25%13%1
720
October1st to 10thNight
34%11%22%24%9%1
720
11th to 20thNight
36%9%23%21%9%3
720
21st to endNight
32%8%22%23%14%2
792
November1st to 10thNight
35%12%20%23%9%1
740
11th to 20thNight
31%12%22%23%11%1
760
21st to endNight
23%10%26%25%13%3
977
December1st to 10thNight
19%9%29%28%14%2
1040
11th to 20thNight
15%9%23%29%18%5%
1040
21st to endNight
16%8%24%33%15%5%
1144
Page generated at 2024-01-10 01:25:00. Version ac07

Copyright 2024 Attilla Danko


Chisasibi Clear Sky Chart |Charts Home