Chimnissing
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chimnissing clear sky chart from 2005-11-05 to 2018-01-12.

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
32%
15476
10%
48230
8%
15439
34%
15439
13%
37055

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%
916
1%
2787
0%
913
11%
913
3%
2588
January16th to endNight
15%
768
4%
2496
2%
768
17%
768
4%
2240
February1st to 15thNight
14%
701
3%
2287
1%
701
17%
701
5%
1967
February16th to endNight
24%
631
7%
2009
3%
631
29%
631
9%
1627
March1st to 15thNight
23%
720
11%
1998
6%
720
28%
720
15%
1528
March16th to endNight
36%
768
18%
2112
12%
768
40%
768
22%
1494
April1st to 15thNight
30%
697
14%
1811
5%
697
34%
697
20%
1330
April16th to endNight
41%
540
18%
1620
12%
540
45%
540
22%
1113
May1st to 15thNight
50%
492
15%
1572
14%
492
53%
492
22%
1044
May16th to endNight
53%
374
14%
1497
17%
374
59%
374
23%
871
June1st to 15thNight
54%
360
11%
1341
12%
360
58%
360
22%
853
June16th to endNight
57%
360
13%
1260
16%
360
61%
360
25%
773
July1st to 15thNight
68%
340
17%
1190
22%
340
70%
340
34%
635
July16th to endNight
58%
485
16%
1510
17%
454
59%
454
27%
906
August1st to 15thNight
61%
539
16%
1609
12%
536
63%
536
30%
978
August16th to endNight
56%
594
17%
1740
12%
594
59%
594
28%
1105
September1st to 15thNight
51%
720
15%
1835
9%
720
53%
720
27%
1274
September16th to endNight
51%
717
18%
1987
13%
717
53%
717
24%
1372
October1st to 15thNight
34%
720
13%
2160
11%
720
37%
720
16%
1610
October16th to endNight
17%
768
7%
2319
4%
768
22%
768
8%
1947
November1st to 15thNight
25%
760
11%
2604
10%
760
28%
760
10%
2031
November16th to endNight
16%
780
5%
2730
5%
780
18%
780
5%
2369
December1st to 15thNight
7%
780
1%
2730
1%
780
8%
780
2%
2558
December16th to endNight
6%
946
2%
3026
1%
946
8%
946
2%
2842

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%9%47%5%34446%33%
49098
Night
18%12%5%8%6%34345%26%
48399
Cloud CoverDay
16%9%46%5%34446%33%
49108
Night
18%12%5%8%6%34445%27%
48403
TransparencyDay
51%6%12%18%9%
48785
Night
60%5%10%14%8%
48230
SeeingDay
20%5%22%29%16%5%
6049
Night
23%10%25%25%13%2
15482

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%18%7%14%9%46%3436%
1388
16th to endDay
13%18%10%15%10%5%5%4338%
1728
February1st to 15thDay
14%15%7%14%9%5%5%33414%
1575
16th to endDay
15%15%8%11%7%45%45%418%
1461
March1st to 15thDay
14%10%36%7%35%445%31%
1951
16th to endDay
14%7%35%435%45%6%40%
2112
April1st to 15thDay
20%9%35%425%345%34%
2146
16th to endDay
18%7%25%42335%7%40%
2340
May1st to 15thDay
17%7%25%423436%41%
2379
16th to endDay
13%5%2442445%7%45%
2618
June1st to 15thDay
15%5%244245%6%7%41%
2615
16th to endDay
12%5%243245%6%9%41%
2700
July1st to 15thDay
10%42432346%8%49%
2700
16th to endDay
9%3244245%6%7%47%
2550
August1st to 15thDay
11%5%2442345%7%48%
2340
16th to endDay
12%5%25%5%24448%43%
2450
September1st to 15thDay
16%7%25%434346%40%
2124
16th to endDay
17%6%25%434346%42%
1972
October1st to 15thDay
24%8%36%5%33345%31%
1800
16th to endDay
33%12%37%5%2343417%
1902
November1st to 15thDay
22%14%5%8%5%34345%21%
1583
16th to endDay
24%22%7%9%6%3432410%
1560
December1st to 15thDay
20%23%10%16%8%233235%
1560
16th to endDay
20%22%11%13%8%442236%
1544
January1st to 15thNight
22%19%8%14%9%45%4236%
2787
16th to endNight
15%16%9%15%12%443349%
2496
February1st to 15thNight
14%18%9%14%8%3443312%
2285
16th to endNight
17%12%7%11%7%45%335%20%
2009
March1st to 15thNight
17%11%5%7%8%24335%29%
1986
16th to endNight
14%9%48%5%23345%38%
2112
April1st to 15thNight
22%9%35%5%33435%33%
1811
16th to endNight
17%8%36%5%3435%6%36%
1620
May1st to 15thNight
17%5%26%5%34448%37%
1572
16th to endNight
12%5%25%5%35%46%6%43%
1495
June1st to 15thNight
14%425%6%36%45%8%38%
1341
16th to endNight
11%6%34435%46%9%41%
1260
July1st to 15thNight
8%5%1433345%7%53%
1260
16th to endNight
9%4345%25%45%7%47%
1614
August1st to 15thNight
10%5%244345%47%46%
1620
16th to endNight
13%4245%24447%45%
1740
September1st to 15thNight
17%5%2442446%8%39%
1835
16th to endNight
18%5%25%5%34445%39%
1987
October1st to 15thNight
25%7%35%5%33345%31%
2160
16th to endNight
32%15%37%5%33335%17%
2319
November1st to 15thNight
22%14%5%8%5%24436%21%
2604
16th to endNight
26%21%7%9%5%2323413%
2730
December1st to 15thNight
22%27%9%13%7%332216%
2730
16th to endNight
23%21%10%14%8%342225%
3026

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%16%6%13%10%4445%310%
1388
16th to endDay
14%18%8%13%9%36%44411%
1728
February1st to 15thDay
14%15%8%13%9%35%35%416%
1575
16th to endDay
15%16%7%10%7%4444421%
1461
March1st to 15thDay
16%10%36%7%46%44431%
1962
16th to endDay
14%7%35%5%25%445%40%
2111
April1st to 15thDay
20%9%35%434345%34%
2146
16th to endDay
19%6%24424446%39%
2340
May1st to 15thDay
17%7%35%423346%40%
2379
16th to endDay
14%5%1343445%7%44%
2618
June1st to 15thDay
15%5%24425%46%8%40%
2615
16th to endDay
13%6%2443446%8%40%
2700
July1st to 15thDay
10%42432446%8%48%
2700
16th to endDay
10%325%5%2446%9%45%
2550
August1st to 15thDay
12%5%2442345%7%47%
2340
16th to endDay
11%5%25%434448%43%
2450
September1st to 15thDay
16%8%25%434446%41%
2124
16th to endDay
17%5%245%34346%42%
1972
October1st to 15thDay
24%10%25%423346%31%
1800
16th to endDay
32%13%38%5%2433417%
1902
November1st to 15thDay
22%15%47%5%25%447%20%
1583
16th to endDay
25%21%7%10%6%35%33311%
1560
December1st to 15thDay
20%24%9%13%7%443236%
1560
16th to endDay
20%23%9%11%8%45%3336%
1544
January1st to 15thNight
22%19%7%12%8%443438%
2787
16th to endNight
16%17%8%13%11%45%43410%
2496
February1st to 15thNight
13%19%8%14%7%4345%313%
2278
16th to endNight
18%11%6%10%8%34335%22%
2009
March1st to 15thNight
18%10%5%7%7%34345%29%
1998
16th to endNight
14%9%5%7%423335%39%
2112
April1st to 15thNight
22%9%45%5%24336%32%
1811
16th to endNight
17%7%36%434347%36%
1620
May1st to 15thNight
18%5%25%5%3435%7%37%
1571
16th to endNight
12%5%25%5%345%47%43%
1495
June1st to 15thNight
14%4346%36%45%8%38%
1341
16th to endNight
12%6%244345%6%9%41%
1260
July1st to 15thNight
9%424324447%52%
1260
16th to endNight
9%4246%35%45%7%47%
1614
August1st to 15thNight
10%5%245%2445%8%46%
1620
16th to endNight
12%5%25%5%3345%6%45%
1740
September1st to 15thNight
16%6%25%43345%7%39%
1835
16th to endNight
17%6%25%5%345%46%39%
1987
October1st to 15thNight
25%8%26%5%24435%31%
2160
16th to endNight
32%14%47%423435%17%
2319
November1st to 15thNight
22%15%47%5%33345%22%
2604
16th to endNight
26%20%6%8%5%3333413%
2730
December1st to 15thNight
21%26%10%12%6%342226%
2730
16th to endNight
22%20%9%13%8%444227%
3026

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
81%7%6%3
1389
16th to endDay
80%6%5%42
1728
February1st to 15thDay
73%5%10%8%1
1577
16th to endDay
69%5%10%8%5%
1461
March1st to 15thDay
54%6%14%16%6%
1962
16th to endDay
45%5%12%19%14%2
2112
April1st to 15thDay
51%49%21%10%
2146
16th to endDay
44%5%10%22%14%2
2340
May1st to 15thDay
43%5%10%23%14%1
2379
16th to endDay
37%8%12%24%15%1
2622
June1st to 15thDay
39%8%13%24%13%
2615
16th to endDay
37%9%16%22%13%
2700
July1st to 15thDay
30%8%16%26%15%1
2541
16th to endDay
34%8%14%28%12%
2391
August1st to 15thDay
33%8%17%24%15%
2327
16th to endDay
37%8%16%25%9%
2450
September1st to 15thDay
44%7%14%23%8%
2124
16th to endDay
43%6%13%27%8%
1972
October1st to 15thDay
55%5%10%18%9%
1800
16th to endDay
69%7%10%7%3
1902
November1st to 15thDay
63%7%10%11%6%
1583
16th to endDay
79%5%8%5%1
1560
December1st to 15thDay
86%46%2
1560
16th to endDay
86%45%2
1544
January1st to 15thNight
84%5%6%3
2787
16th to endNight
79%5%7%5%1
2496
February1st to 15thNight
75%5%10%7%1
2287
16th to endNight
67%411%10%5%
2009
March1st to 15thNight
58%5%12%16%6%
1998
16th to endNight
49%49%18%15%1
2112
April1st to 15thNight
53%48%19%12%1
1811
16th to endNight
47%5%9%16%18%1
1620
May1st to 15thNight
46%410%18%17%2
1572
16th to endNight
38%6%14%24%15%1
1497
June1st to 15thNight
42%7%11%22%16%
1341
16th to endNight
38%6%13%25%14%
1260
July1st to 15thNight
28%5%13%28%21%2
1190
16th to endNight
35%7%11%28%14%
1510
August1st to 15thNight
34%6%17%25%14%
1609
16th to endNight
38%6%15%24%14%1
1740
September1st to 15thNight
42%7%13%24%11%
1835
16th to endNight
44%6%12%25%10%
1987
October1st to 15thNight
55%6%9%18%10%
2160
16th to endNight
70%5%9%10%3
2319
November1st to 15thNight
63%5%12%12%4
2604
16th to endNight
75%5%9%7%1
2730
December1st to 15thNight
86%45%21
2730
16th to endNight
87%443
3026

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%23%37%20%3
86
16th to endDay
38%6%25%25%5%
96
February1st to 15thDay
33%13%36%16%
90
16th to endDay
19%16%30%32%1
81
March1st to 15thDay
21%7%34%28%7%
252
16th to endDay
23%428%28%12%2
288
April1st to 15thDay
22%8%28%28%10%2
270
16th to endDay
22%5%27%26%12%4
270
May1st to 15thDay
22%220%30%15%6%
288
16th to endDay
16%123%32%20%5%
331
June1st to 15thDay
19%320%30%21%4
410
16th to endDay
15%318%38%20%3
495
July1st to 15thDay
11%316%38%22%7%
475
16th to endDay
10%120%33%25%6%
331
August1st to 15thDay
13%314%32%25%10%
313
16th to endDay
17%215%30%23%10%
332
September1st to 15thDay
16%220%23%22%14%
315
16th to endDay
18%5%14%25%25%11%
314
October1st to 15thDay
26%6%22%25%13%4
315
16th to endDay
37%12%22%20%6%
318
November1st to 15thDay
23%10%27%28%8%1
103
16th to endDay
33%12%38%15%
90
December1st to 15thDay
22%24%30%18%4
90
16th to endDay
33%20%36%9%
96
January1st to 15thNight
29%20%29%15%4
918
16th to endNight
22%14%32%23%5%1
768
February1st to 15thNight
21%14%36%21%5%
704
16th to endNight
22%8%32%28%8%
631
March1st to 15thNight
22%9%35%23%7%
720
16th to endNight
18%6%28%29%14%1
768
April1st to 15thNight
25%8%29%27%8%
697
16th to endNight
20%6%25%30%17%
540
May1st to 15thNight
19%217%38%18%3
492
16th to endNight
14%221%35%24%1
375
June1st to 15thNight
14%418%40%20%1
360
16th to endNight
15%118%36%25%2
360
July1st to 15thNight
10%212%40%29%4
340
16th to endNight
8%221%35%29%2
485
August1st to 15thNight
11%315%35%27%5%
539
16th to endNight
15%217%28%30%4
594
September1st to 15thNight
19%417%28%20%9%
720
16th to endNight
17%6%15%32%21%6%
717
October1st to 15thNight
27%8%23%24%12%2
720
16th to endNight
38%13%23%18%4
768
November1st to 15thNight
29%13%26%19%10%
760
16th to endNight
35%15%25%17%5%
780
December1st to 15thNight
35%21%28%12%2
780
16th to endNight
30%19%32%14%2
946
Page generated at 2018-01-12 22:01:29. Version ac04

Copyright 2018 A. Danko


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