Goderich
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Goderich clear sky chart from 2005-11-05 to 2018-04-23.

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%
16116
11%
49450
8%
16077
35%
16077
15%
37514

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%
973
3%
2770
1%
970
12%
970
5%
2511
January16th to endNight
13%
851
4%
2723
2%
851
15%
851
4%
2414
February1st to 15thNight
15%
761
5%
2482
2%
761
19%
761
6%
2149
February16th to endNight
21%
683
7%
2105
3%
683
25%
683
10%
1711
March1st to 15thNight
26%
780
11%
2200
6%
780
30%
780
14%
1724
March16th to endNight
34%
832
17%
2288
10%
832
39%
832
21%
1655
April1st to 15thNight
30%
708
13%
1967
6%
708
35%
708
19%
1437
April16th to endNight
38%
558
18%
1672
11%
558
43%
558
24%
1115
May1st to 15thNight
44%
540
15%
1620
12%
540
48%
540
24%
1096
May16th to endNight
50%
425
17%
1548
15%
425
58%
425
25%
919
June1st to 15thNight
49%
360
13%
1308
13%
360
55%
360
23%
792
June16th to endNight
55%
360
15%
1260
17%
360
60%
360
27%
750
July1st to 15thNight
66%
379
18%
1229
21%
379
68%
379
35%
697
July16th to endNight
63%
564
15%
1551
14%
531
64%
531
31%
964
August1st to 15thNight
64%
539
16%
1609
14%
536
66%
536
29%
1000
August16th to endNight
61%
573
21%
1719
16%
573
63%
573
31%
1053
September1st to 15thNight
54%
710
17%
1895
12%
710
56%
710
31%
1244
September16th to endNight
55%
717
19%
1980
14%
717
58%
717
30%
1274
October1st to 15thNight
37%
720
14%
2125
11%
720
41%
720
18%
1541
October16th to endNight
20%
768
9%
2355
5%
768
25%
768
9%
1928
November1st to 15thNight
27%
760
13%
2509
11%
760
31%
760
12%
1932
November16th to endNight
18%
780
7%
2730
6%
780
20%
780
7%
2299
December1st to 15thNight
8%
780
2%
2730
1%
780
9%
780
3%
2488
December16th to endNight
8%
995
2%
3075
0%
995
10%
995
4%
2821

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%10%5%7%5%24446%31%
50061
Night
18%12%5%8%6%23345%28%
49625
Cloud CoverDay
16%10%47%5%2445%6%31%
50071
Night
18%12%5%8%6%24345%28%
49629
TransparencyDay
53%6%12%18%9%1
49754
Night
58%5%10%15%8%1
49450
SeeingDay
20%6%24%26%15%6%
6445
Night
23%9%26%27%11%1
16122

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
20%17%10%14%9%4312310%
1496
16th to endDay
15%18%11%17%9%332339%
1849
February1st to 15thDay
15%17%9%15%9%4322315%
1710
16th to endDay
16%16%8%12%7%3433419%
1653
March1st to 15thDay
15%13%7%11%6%24335%25%
2079
16th to endDay
16%8%5%6%6%24345%33%
2288
April1st to 15thDay
20%11%6%5%334346%30%
2323
16th to endDay
18%7%34423348%39%
2402
May1st to 15thDay
18%6%25%5%24446%37%
2331
16th to endDay
12%5%34425%45%7%43%
2565
June1st to 15thDay
13%6%25%43446%9%39%
2649
16th to endDay
13%5%244345%6%8%41%
2700
July1st to 15thDay
9%42432446%9%47%
2655
16th to endDay
9%4244245%6%9%45%
2509
August1st to 15thDay
9%5%24435%5%7%9%41%
2340
16th to endDay
11%5%245%245%5%8%43%
2480
September1st to 15thDay
15%6%25%5%245%5%8%38%
2053
16th to endDay
17%42442435%8%42%
1980
October1st to 15thDay
23%9%35%5%33346%31%
1834
16th to endDay
31%13%46%434345%18%
1869
November1st to 15thDay
21%15%46%424435%26%
1678
16th to endDay
23%23%7%8%5%1334314%
1560
December1st to 15thDay
21%25%13%12%6%232227%
1560
16th to endDay
19%24%11%12%9%243336%
1498
January1st to 15thNight
23%16%10%14%9%3322310%
2770
16th to endNight
16%16%11%15%9%4333312%
2723
February1st to 15thNight
16%17%7%14%10%4333315%
2480
16th to endNight
16%13%8%12%7%3444419%
2105
March1st to 15thNight
16%12%5%9%6%34446%25%
2188
16th to endNight
16%9%5%7%5%2444435%
2288
April1st to 15thNight
23%9%35%423446%31%
1967
16th to endNight
15%8%35%5%3335%5%40%
1672
May1st to 15thNight
17%7%3443445%8%36%
1620
16th to endNight
13%32443345%7%45%
1546
June1st to 15thNight
13%435%5%2446%8%40%
1308
16th to endNight
12%425%5%3346%8%43%
1260
July1st to 15thNight
9%3224245%5%6%53%
1302
16th to endNight
9%325%425%5%5%7%47%
1658
August1st to 15thNight
9%4145%35%5%5%8%45%
1620
16th to endNight
11%5%24423446%49%
1719
September1st to 15thNight
15%43443345%6%45%
1895
16th to endNight
15%5%145%2345%6%45%
1980
October1st to 15thNight
23%6%36%5%23345%33%
2125
16th to endNight
32%10%36%5%3343421%
2355
November1st to 15thNight
22%14%36%5%34435%25%
2509
16th to endNight
25%23%7%8%41222416%
2730
December1st to 15thNight
21%26%12%11%6%122238%
2730
16th to endNight
22%22%12%11%6%233339%
3075

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
20%18%10%13%9%4323310%
1496
16th to endDay
15%17%11%17%9%432339%
1849
February1st to 15thDay
15%18%9%14%10%4323315%
1710
16th to endDay
16%16%8%12%7%3433419%
1653
March1st to 15thDay
16%14%7%10%6%34335%25%
2090
16th to endDay
17%8%5%6%6%24445%33%
2287
April1st to 15thDay
20%11%6%5%323346%30%
2323
16th to endDay
18%7%2442335%7%39%
2402
May1st to 15thDay
19%6%25%5%2445%6%38%
2331
16th to endDay
12%5%3442445%7%44%
2565
June1st to 15thDay
13%6%25%43446%9%39%
2649
16th to endDay
13%5%2443446%8%41%
2700
July1st to 15thDay
9%424325%46%9%47%
2655
16th to endDay
9%414425%5%7%9%45%
2509
August1st to 15thDay
10%5%24435%5%7%8%42%
2340
16th to endDay
11%5%245%245%5%8%43%
2480
September1st to 15thDay
16%6%25%5%245%5%8%38%
2053
16th to endDay
18%424424448%42%
1980
October1st to 15thDay
23%8%35%5%3335%5%31%
1834
16th to endDay
31%13%46%5%3434419%
1869
November1st to 15thDay
20%15%36%5%24446%26%
1678
16th to endDay
23%23%7%8%42334414%
1560
December1st to 15thDay
21%26%13%12%6%132227%
1560
16th to endDay
19%24%11%12%8%233336%
1498
January1st to 15thNight
22%17%10%14%9%3322310%
2770
16th to endNight
16%16%10%16%9%4333311%
2723
February1st to 15thNight
16%17%6%15%10%4333315%
2473
16th to endNight
16%13%7%12%7%3443419%
2105
March1st to 15thNight
17%12%5%9%7%35%346%25%
2200
16th to endNight
16%9%5%7%5%2444435%
2288
April1st to 15thNight
23%9%35%423446%31%
1967
16th to endNight
15%8%35%5%23345%40%
1672
May1st to 15thNight
17%7%3443445%8%36%
1619
16th to endNight
13%41443446%7%45%
1546
June1st to 15thNight
13%5%35%5%2436%8%40%
1308
16th to endNight
12%425%5%3345%9%42%
1260
July1st to 15thNight
8%323415%5%5%6%53%
1302
16th to endNight
9%325%425%46%8%47%
1658
August1st to 15thNight
9%425%435%6%5%8%45%
1620
16th to endNight
12%5%14433446%49%
1719
September1st to 15thNight
15%33442345%6%45%
1895
16th to endNight
15%41443335%7%45%
1980
October1st to 15thNight
23%7%27%5%2335%5%33%
2125
16th to endNight
32%11%36%5%3343421%
2355
November1st to 15thNight
22%14%36%5%34435%26%
2509
16th to endNight
26%24%6%8%41322416%
2730
December1st to 15thNight
21%26%12%11%5%222238%
2730
16th to endNight
22%22%12%10%6%233339%
3075

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%46%5%1
1497
16th to endDay
80%5%6%42
1849
February1st to 15thDay
76%37%10%2
1712
16th to endDay
69%49%10%4
1653
March1st to 15thDay
63%411%13%6%
2090
16th to endDay
52%5%13%17%9%1
2288
April1st to 15thDay
55%5%11%18%9%
2323
16th to endDay
44%5%14%19%13%2
2402
May1st to 15thDay
46%6%10%23%12%
2331
16th to endDay
39%6%14%22%14%2
2569
June1st to 15thDay
40%7%13%24%12%1
2649
16th to endDay
39%7%15%25%12%
2700
July1st to 15thDay
32%7%14%26%17%2
2499
16th to endDay
34%8%16%26%12%1
2353
August1st to 15thDay
36%8%18%22%11%1
2327
16th to endDay
37%7%16%26%11%1
2480
September1st to 15thDay
42%7%16%21%10%1
2053
16th to endDay
39%6%14%28%9%
1980
October1st to 15thDay
53%5%9%18%10%1
1834
16th to endDay
68%6%12%9%4
1869
November1st to 15thDay
60%7%10%14%6%
1678
16th to endDay
74%5%8%8%1
1560
December1st to 15thDay
85%45%4
1560
16th to endDay
84%45%4
1498
January1st to 15thNight
80%47%41
2770
16th to endNight
77%6%7%5%2
2723
February1st to 15thNight
75%47%9%1
2482
16th to endNight
66%5%11%10%5%
2105
March1st to 15thNight
59%6%9%16%6%
2200
16th to endNight
51%410%19%11%2
2288
April1st to 15thNight
52%5%10%19%11%
1967
16th to endNight
45%49%17%19%3
1672
May1st to 15thNight
45%5%9%22%14%2
1620
16th to endNight
36%7%12%26%14%3
1548
June1st to 15thNight
40%5%12%24%15%1
1308
16th to endNight
37%5%13%24%16%1
1260
July1st to 15thNight
28%7%9%29%21%2
1229
16th to endNight
34%8%14%23%17%1
1551
August1st to 15thNight
34%8%13%27%13%1
1609
16th to endNight
35%6%12%28%15%1
1719
September1st to 15thNight
37%7%14%26%13%1
1895
16th to endNight
38%6%16%25%13%
1980
October1st to 15thNight
51%7%8%19%11%1
2125
16th to endNight
66%6%10%11%4
2355
November1st to 15thNight
60%6%11%14%6%
2509
16th to endNight
73%49%10%2
2730
December1st to 15thNight
83%46%41
2730
16th to endNight
82%5%7%4
3075

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
27%15%34%18%4
122
16th to endDay
29%11%36%20%1
144
February1st to 15thDay
28%16%46%8%
135
16th to endDay
20%22%38%16%1
120
March1st to 15thDay
26%10%30%23%8%
275
16th to endDay
22%6%32%27%9%1
352
April1st to 15thDay
29%8%27%21%9%2
330
16th to endDay
22%6%29%22%12%5%
289
May1st to 15thDay
21%5%27%24%15%5%
288
16th to endDay
15%5%24%30%15%8%
331
June1st to 15thDay
15%325%31%20%3
444
16th to endDay
15%222%36%16%5%
495
July1st to 15thDay
11%319%32%24%9%
475
16th to endDay
9%120%33%26%8%
369
August1st to 15thDay
12%216%28%25%15%
313
16th to endDay
18%314%25%25%13%
332
September1st to 15thDay
14%416%26%23%14%
315
16th to endDay
17%414%23%25%13%
314
October1st to 15thDay
24%6%23%26%14%4
315
16th to endDay
36%9%28%20%5%
285
November1st to 15thDay
23%11%32%22%10%
126
16th to endDay
30%22%28%14%4
90
December1st to 15thDay
33%32%20%14%
90
16th to endDay
34%20%34%10%
96
January1st to 15thNight
27%18%32%17%4
975
16th to endNight
22%13%35%23%5%
851
February1st to 15thNight
24%14%33%22%4
764
16th to endNight
25%10%33%24%5%
683
March1st to 15thNight
22%11%31%25%8%
780
16th to endNight
21%5%30%29%10%1
832
April1st to 15thNight
26%9%27%28%6%
708
16th to endNight
20%6%28%31%12%1
558
May1st to 15thNight
21%323%34%15%1
540
16th to endNight
16%323%36%18%1
426
June1st to 15thNight
15%322%42%15%1
360
16th to endNight
14%319%39%22%1
360
July1st to 15thNight
8%215%48%20%3
379
16th to endNight
10%114%45%24%3
564
August1st to 15thNight
10%114%37%32%4
539
16th to endNight
15%214%32%30%4
573
September1st to 15thNight
16%318%31%21%8%
710
16th to endNight
16%417%31%23%6%
717
October1st to 15thNight
24%8%23%25%16%2
720
16th to endNight
36%10%26%22%3
768
November1st to 15thNight
28%10%27%22%9%1
760
16th to endNight
35%16%23%19%5%
780
December1st to 15thNight
34%19%29%14%2
780
16th to endNight
30%16%34%15%2
995
Page generated at 2018-04-24 10:03:03. Version ac04

Copyright 2018 A. Danko


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