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 2017-09-16.

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%
15227
11%
46733
8%
15188
36%
15188
15%
35337

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
9%
898
3%
2556
1%
895
11%
895
5%
2319
January16th to endNight
13%
786
4%
2514
2%
786
16%
786
4%
2243
February1st to 15thNight
15%
701
4%
2287
1%
701
18%
701
6%
1984
February16th to endNight
21%
631
7%
1945
3%
631
26%
631
10%
1586
March1st to 15thNight
26%
720
12%
2031
7%
720
30%
720
14%
1599
March16th to endNight
34%
768
17%
2112
10%
768
39%
768
20%
1541
April1st to 15thNight
30%
653
13%
1815
6%
653
36%
653
20%
1319
April16th to endNight
38%
540
18%
1620
11%
540
43%
540
24%
1085
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
54%
658
17%
1818
12%
658
56%
658
30%
1176
October1st to 15thNight
37%
660
15%
1948
12%
660
40%
660
18%
1416
October16th to endNight
19%
704
8%
2159
4%
704
24%
704
9%
1773
November1st to 15thNight
27%
700
14%
2311
12%
700
31%
700
13%
1754
November16th to endNight
18%
720
7%
2520
7%
720
20%
720
7%
2132
December1st to 15thNight
8%
720
2%
2520
1%
720
9%
720
3%
2296
December16th to endNight
8%
918
2%
2838
0%
918
11%
918
4%
2599

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%32%
48003
Night
18%12%5%8%6%24345%28%
46908
Cloud CoverDay
16%10%47%5%2445%6%32%
48013
Night
18%12%5%8%5%24345%28%
46912
TransparencyDay
52%6%12%18%9%
47696
Night
57%5%10%16%8%1
46733
SeeingDay
19%6%24%27%16%6%
5759
Night
23%9%26%27%12%1
15233

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%18%11%14%8%3312310%
1380
16th to endDay
15%18%12%17%9%332338%
1707
February1st to 15thDay
14%17%10%15%8%4332314%
1575
16th to endDay
15%17%9%12%7%3423418%
1527
March1st to 15thDay
15%12%7%11%6%34435%24%
1918
16th to endDay
16%9%6%6%6%24445%32%
2112
April1st to 15thDay
19%11%5%4334346%32%
2144
16th to endDay
17%7%34423348%39%
2340
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
18%42442435%8%41%
1815
October1st to 15thDay
22%9%25%5%34446%31%
1681
16th to endDay
31%13%47%434335%17%
1713
November1st to 15thDay
20%15%46%424435%27%
1546
16th to endDay
23%23%7%8%5%1334313%
1440
December1st to 15thDay
21%25%13%11%6%232227%
1440
16th to endDay
19%25%11%12%7%242336%
1383
January1st to 15thNight
23%17%10%14%8%2322310%
2556
16th to endNight
16%17%11%15%10%4332311%
2514
February1st to 15thNight
16%18%7%15%9%4333315%
2285
16th to endNight
16%14%8%12%8%35%44419%
1945
March1st to 15thNight
17%11%5%9%7%35%446%25%
2019
16th to endNight
16%10%5%6%5%25%44434%
2112
April1st to 15thNight
23%9%35%4235%46%32%
1815
16th to endNight
15%8%35%5%3335%5%39%
1620
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
16%5%135%2335%6%44%
1818
October1st to 15thNight
23%7%37%5%23345%33%
1948
16th to endNight
33%10%36%6%3343420%
2159
November1st to 15thNight
21%14%36%5%33436%27%
2311
16th to endNight
26%23%7%8%41223415%
2520
December1st to 15thNight
22%25%12%11%5%222238%
2520
16th to endNight
23%22%12%11%5%233339%
2838

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%19%11%14%8%4212310%
1380
16th to endDay
15%18%12%17%10%432339%
1707
February1st to 15thDay
14%17%9%15%9%4333315%
1575
16th to endDay
15%17%8%12%7%3433418%
1527
March1st to 15thDay
16%12%7%11%6%34335%24%
1929
16th to endDay
17%8%6%6%6%24445%32%
2111
April1st to 15thDay
20%11%6%4324346%32%
2144
16th to endDay
18%8%2442335%8%39%
2340
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
19%42441445%8%41%
1815
October1st to 15thDay
23%8%35%5%3435%6%31%
1681
16th to endDay
32%13%46%5%2433417%
1713
November1st to 15thDay
20%15%36%423445%27%
1546
16th to endDay
23%23%7%8%5%2334313%
1440
December1st to 15thDay
21%26%12%11%6%132227%
1440
16th to endDay
20%25%11%12%7%232336%
1383
January1st to 15thNight
23%17%10%14%8%2322310%
2556
16th to endNight
16%17%11%16%10%3433311%
2514
February1st to 15thNight
16%17%7%15%10%3333315%
2278
16th to endNight
16%14%7%13%7%35%5%4418%
1945
March1st to 15thNight
17%11%5%9%7%35%346%24%
2031
16th to endNight
16%9%5%7%5%2444434%
2112
April1st to 15thNight
23%9%35%413446%32%
1815
16th to endNight
15%8%35%6%23346%39%
1620
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
17%41443335%7%44%
1818
October1st to 15thNight
23%7%37%5%2335%5%33%
1948
16th to endNight
32%11%36%6%3343420%
2159
November1st to 15thNight
21%14%36%5%24435%27%
2311
16th to endNight
26%23%6%8%41222415%
2520
December1st to 15thNight
22%25%12%11%5%221338%
2520
16th to endNight
23%22%12%10%5%233339%
2838

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
1381
16th to endDay
81%5%6%42
1707
February1st to 15thDay
76%37%10%1
1577
16th to endDay
70%49%10%4
1527
March1st to 15thDay
62%411%13%6%
1929
16th to endDay
52%5%14%16%8%1
2112
April1st to 15thDay
53%5%11%19%9%
2144
16th to endDay
44%5%14%19%13%2
2340
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
40%6%15%26%9%
1815
October1st to 15thDay
53%6%10%17%11%1
1681
16th to endDay
70%6%11%8%2
1713
November1st to 15thDay
59%7%10%15%7%
1546
16th to endDay
75%5%8%7%1
1440
December1st to 15thDay
85%45%3
1440
16th to endDay
84%45%4
1383
January1st to 15thNight
80%47%42
2556
16th to endNight
79%5%7%5%1
2514
February1st to 15thNight
76%47%9%1
2287
16th to endNight
66%6%11%10%5%
1945
March1st to 15thNight
60%6%9%17%5%
2031
16th to endNight
52%410%19%10%2
2112
April1st to 15thNight
52%5%10%20%11%
1815
16th to endNight
45%49%17%18%3
1620
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
39%5%16%24%13%
1818
October1st to 15thNight
51%7%8%19%11%1
1948
16th to endNight
67%6%10%10%4
2159
November1st to 15thNight
58%6%11%14%7%
2311
16th to endNight
74%49%10%1
2520
December1st to 15thNight
83%46%41
2520
16th to endNight
82%5%7%4
2838

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
25%14%40%12%6%
81
16th to endDay
34%12%30%21%1
96
February1st to 15thDay
25%17%50%6%
90
16th to endDay
17%22%39%18%2
81
March1st to 15thDay
26%11%29%24%7%
219
16th to endDay
24%6%30%26%10%1
288
April1st to 15thDay
26%8%26%25%10%2
270
16th to endDay
22%7%31%21%11%6%
270
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
20%415%27%22%9%
254
October1st to 15thDay
23%6%22%28%14%4
255
16th to endDay
38%9%26%19%4
225
November1st to 15thDay
15%11%34%21%15%1
84
16th to endDay
30%20%33%10%6%
60
December1st to 15thDay
36%35%16%11%
60
16th to endDay
40%20%34%4
64
January1st to 15thNight
27%18%32%16%4
900
16th to endNight
22%13%34%22%5%
786
February1st to 15thNight
24%15%33%22%4
704
16th to endNight
24%11%32%25%6%
631
March1st to 15thNight
22%12%30%25%8%
720
16th to endNight
21%6%29%28%11%2
768
April1st to 15thNight
26%9%28%29%6%
653
16th to endNight
20%6%29%30%12%1
540
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
17%417%32%21%5%
658
October1st to 15thNight
24%8%23%25%16%2
660
16th to endNight
36%10%27%21%3
704
November1st to 15thNight
26%10%29%23%9%1
700
16th to endNight
35%15%23%19%5%
720
December1st to 15thNight
34%18%29%14%2
720
16th to endNight
31%15%34%15%3
918
Page generated at 2017-09-16 17:07:02. Version ac04

Copyright 2017 A. Danko


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