Kitchener-Waterloo
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kitchener-Waterloo clear sky chart from 2005-11-05 to 2018-02-22.

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%
15503
14%
48661
9%
15466
39%
15466
18%
34342

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
13%
776
9%
2625
4%
776
19%
776
8%
2103
January16th to endNight
15%
832
9%
2704
3%
832
22%
832
9%
2161
February1st to 15thNight
16%
762
8%
2482
2%
761
22%
761
9%
1964
February16th to endNight
20%
659
10%
2075
4%
659
27%
659
11%
1563
March1st to 15thNight
21%
720
12%
1995
6%
720
27%
720
15%
1520
March16th to endNight
31%
768
20%
2112
10%
768
39%
768
23%
1450
April1st to 15thNight
25%
703
15%
1832
6%
703
31%
703
21%
1334
April16th to endNight
37%
540
20%
1620
10%
540
44%
540
24%
1054
May1st to 15thNight
40%
540
16%
1620
10%
540
46%
540
24%
1079
May16th to endNight
46%
376
17%
1499
13%
376
57%
376
24%
853
June1st to 15thNight
46%
360
13%
1426
12%
360
55%
360
22%
843
June16th to endNight
49%
360
15%
1260
15%
360
57%
360
27%
749
July1st to 15thNight
62%
340
18%
1248
23%
340
66%
340
37%
626
July16th to endNight
57%
551
15%
1582
11%
518
60%
518
33%
951
August1st to 15thNight
66%
539
18%
1609
13%
536
70%
536
35%
944
August16th to endNight
60%
600
23%
1746
14%
600
65%
600
33%
1056
September1st to 15thNight
53%
720
21%
1854
12%
720
58%
720
34%
1183
September16th to endNight
54%
717
22%
1980
16%
717
57%
717
31%
1250
October1st to 15thNight
40%
720
18%
2157
14%
720
46%
720
23%
1445
October16th to endNight
24%
768
14%
2304
8%
768
33%
768
15%
1706
November1st to 15thNight
33%
760
16%
2559
14%
760
38%
760
18%
1771
November16th to endNight
22%
780
10%
2730
6%
780
28%
780
11%
2042
December1st to 15thNight
13%
780
5%
2730
2%
780
18%
780
7%
2218
December16th to endNight
9%
832
5%
2912
1%
832
14%
832
5%
2477

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
15%9%47%6%35%5%5%7%30%
49577
Night
14%8%47%6%35%45%7%33%
48838
Cloud CoverDay
14%9%47%6%35%5%5%7%30%
49587
Night
14%8%47%6%3445%7%33%
48842
TransparencyDay
51%7%13%17%9%
49272
Night
49%6%12%19%10%1
48661
SeeingDay
18%9%27%23%14%6%
6062
Night
18%10%30%27%11%1
15510

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
17%14%7%9%8%36%436%17%
1641
16th to endDay
13%15%8%13%9%46%445%14%
1872
February1st to 15thDay
15%15%7%10%8%46%5%46%15%
1710
16th to endDay
16%14%6%9%8%45%35%6%18%
1542
March1st to 15thDay
15%12%5%10%7%35%35%5%25%
1953
16th to endDay
14%9%48%6%35%446%31%
2112
April1st to 15thDay
20%10%36%43445%5%29%
2124
16th to endDay
17%10%25%423336%37%
2340
May1st to 15thDay
17%7%36%5%24447%34%
2331
16th to endDay
12%5%35%5%45%5%5%8%38%
2613
June1st to 15thDay
14%5%25%5%35%5%6%8%36%
2529
16th to endDay
13%425%5%35%5%6%9%37%
2700
July1st to 15thDay
9%426%5%35%6%7%9%38%
2634
16th to endDay
10%5%26%6%36%5%7%9%35%
2477
August1st to 15thDay
8%6%26%6%47%6%7%8%36%
2340
16th to endDay
12%5%26%5%35%6%6%8%37%
2444
September1st to 15thDay
14%6%25%5%3446%9%36%
2103
16th to endDay
14%435%5%25%46%6%40%
1980
October1st to 15thDay
21%7%36%6%3435%5%31%
1803
16th to endDay
24%10%38%5%35%5%46%22%
1917
November1st to 15thDay
14%9%48%6%35%45%7%29%
1628
16th to endDay
17%14%7%8%6%3446%6%20%
1560
December1st to 15thDay
15%16%7%11%7%46%6%5%5%13%
1560
16th to endDay
20%15%8%11%9%5%5%45%411%
1664
January1st to 15thNight
20%13%5%8%7%45%445%19%
2625
16th to endNight
13%13%8%10%7%45%5%5%6%18%
2704
February1st to 15thNight
14%12%6%9%7%46%5%5%6%20%
2480
16th to endNight
15%10%5%9%8%35%5%5%7%23%
2075
March1st to 15thNight
17%9%37%7%35%447%28%
1983
16th to endNight
14%9%36%424445%39%
2112
April1st to 15thNight
19%8%36%5%24346%33%
1832
16th to endNight
11%7%26%6%35%45%5%42%
1620
May1st to 15thNight
15%6%25%5%3445%7%38%
1620
16th to endNight
11%41442445%7%46%
1497
June1st to 15thNight
11%425%5%26%5%6%7%42%
1426
16th to endNight
10%3246%3445%9%45%
1260
July1st to 15thNight
432332445%9%56%
1323
16th to endNight
8%325%42446%9%47%
1689
August1st to 15thNight
6%31443447%9%48%
1620
16th to endNight
7%6%2443345%7%50%
1746
September1st to 15thNight
11%425%415%45%7%47%
1854
16th to endNight
12%414425%45%8%46%
1980
October1st to 15thNight
17%6%36%43335%7%39%
2157
16th to endNight
19%8%47%5%3445%6%29%
2304
November1st to 15thNight
14%8%36%5%345%5%7%33%
2559
16th to endNight
18%11%47%7%35%5%47%24%
2730
December1st to 15thNight
18%14%6%9%7%35%45%6%17%
2730
16th to endNight
20%13%7%12%8%46%445%12%
2912

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
17%14%6%10%8%45%436%19%
1641
16th to endDay
13%16%7%13%9%45%435%15%
1872
February1st to 15thDay
15%16%7%10%8%36%5%5%6%15%
1710
16th to endDay
16%14%6%9%9%35%446%19%
1542
March1st to 15thDay
15%12%6%9%7%35%45%5%24%
1964
16th to endDay
14%9%5%8%6%3345%6%31%
2111
April1st to 15thDay
20%9%46%5%3445%6%29%
2124
16th to endDay
17%10%35%5%22446%37%
2340
May1st to 15thDay
17%7%37%5%2445%7%34%
2331
16th to endDay
11%5%36%5%46%5%5%8%38%
2613
June1st to 15thDay
14%5%25%5%35%5%6%8%37%
2529
16th to endDay
12%5%25%5%35%6%6%10%36%
2700
July1st to 15thDay
8%5%25%5%35%6%7%10%38%
2634
16th to endDay
9%5%25%7%45%5%8%9%35%
2477
August1st to 15thDay
8%5%26%7%36%6%7%9%36%
2340
16th to endDay
11%6%26%5%35%6%6%8%37%
2444
September1st to 15thDay
13%6%36%5%3446%8%37%
2103
16th to endDay
14%5%25%5%2446%7%40%
1980
October1st to 15thDay
20%8%36%6%3445%5%32%
1803
16th to endDay
23%11%37%5%345%5%6%22%
1917
November1st to 15thDay
14%10%38%6%35%5%5%6%30%
1628
16th to endDay
17%15%6%8%6%3446%6%20%
1560
December1st to 15thDay
15%16%6%11%8%45%6%5%414%
1560
16th to endDay
20%15%8%10%7%45%45%412%
1664
January1st to 15thNight
21%12%5%10%7%35%445%19%
2625
16th to endNight
13%14%7%11%6%46%5%46%18%
2704
February1st to 15thNight
14%13%6%9%7%36%5%5%5%20%
2473
16th to endNight
14%11%410%8%35%5%48%23%
2075
March1st to 15thNight
17%9%38%6%35%447%27%
1995
16th to endNight
14%9%45%424345%40%
2112
April1st to 15thNight
19%8%35%5%24346%34%
1832
16th to endNight
11%6%35%6%4435%6%42%
1620
May1st to 15thNight
14%6%35%5%345%48%38%
1619
16th to endNight
11%4146%2446%7%46%
1497
June1st to 15thNight
11%4246%35%5%6%8%41%
1426
16th to endNight
9%5%245%3446%8%45%
1260
July1st to 15thNight
431332445%9%56%
1323
16th to endNight
8%325%42446%9%47%
1689
August1st to 15thNight
6%3145%345%7%9%49%
1620
16th to endNight
7%6%245%2435%7%51%
1746
September1st to 15thNight
11%5%25%324448%47%
1854
16th to endNight
12%4245%2445%8%46%
1980
October1st to 15thNight
17%7%25%42345%7%39%
2157
16th to endNight
19%8%46%6%35%446%29%
2304
November1st to 15thNight
14%7%36%5%345%5%7%33%
2559
16th to endNight
19%10%47%6%445%47%25%
2730
December1st to 15thNight
18%14%5%9%7%35%45%6%18%
2730
16th to endNight
20%13%7%12%7%45%5%5%5%12%
2912

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
67%5%10%10%5%
1642
16th to endDay
70%5%10%8%4
1872
February1st to 15thDay
68%6%9%11%3
1712
16th to endDay
65%5%11%11%5%1
1542
March1st to 15thDay
60%6%12%14%6%
1964
16th to endDay
53%5%11%17%10%1
2112
April1st to 15thDay
55%5%11%18%9%
2124
16th to endDay
48%410%20%14%1
2340
May1st to 15thDay
48%6%12%21%11%
2331
16th to endDay
42%7%14%20%12%1
2617
June1st to 15thDay
42%7%14%22%11%1
2529
16th to endDay
41%7%16%21%11%
2700
July1st to 15thDay
36%9%13%23%15%1
2480
16th to endDay
42%8%14%21%10%2
2321
August1st to 15thDay
41%9%17%18%11%1
2327
16th to endDay
42%7%14%22%10%1
2444
September1st to 15thDay
42%7%16%21%11%
2103
16th to endDay
41%6%14%27%9%
1980
October1st to 15thDay
52%6%11%16%11%1
1803
16th to endDay
60%8%13%12%5%
1917
November1st to 15thDay
53%7%15%15%7%
1628
16th to endDay
62%7%13%11%5%
1560
December1st to 15thDay
70%9%10%7%2
1560
16th to endDay
73%7%8%7%2
1664
January1st to 15thNight
65%6%10%11%6%
2625
16th to endNight
63%7%12%11%4
2704
February1st to 15thNight
62%7%11%14%4
2482
16th to endNight
58%5%13%13%7%
2075
March1st to 15thNight
55%6%12%17%7%
1995
16th to endNight
46%49%21%15%2
2112
April1st to 15thNight
50%410%19%12%1
1832
16th to endNight
42%5%9%20%19%3
1620
May1st to 15thNight
43%6%10%24%12%2
1620
16th to endNight
36%6%14%25%13%3
1499
June1st to 15thNight
38%6%12%25%15%1
1426
16th to endNight
35%7%14%24%16%1
1260
July1st to 15thNight
24%7%13%29%23%2
1248
16th to endNight
33%7%15%24%16%3
1582
August1st to 15thNight
29%8%17%30%12%2
1609
16th to endNight
32%7%11%29%17%1
1746
September1st to 15thNight
34%6%13%27%16%1
1854
16th to endNight
35%7%11%29%15%
1980
October1st to 15thNight
43%6%11%23%14%
2157
16th to endNight
53%6%14%18%7%
2304
November1st to 15thNight
48%7%13%17%11%1
2559
16th to endNight
58%6%15%14%5%
2730
December1st to 15thNight
66%7%12%10%2
2730
16th to endNight
72%6%10%7%2
2912

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
19%23%34%18%3
111
16th to endDay
28%14%43%11%1
144
February1st to 15thDay
28%25%34%10%1
135
16th to endDay
28%24%36%11%1
100
March1st to 15thDay
24%13%31%24%6%
254
16th to endDay
24%7%33%25%7%1
288
April1st to 15thDay
22%15%29%22%10%
270
16th to endDay
20%11%31%18%13%3
270
May1st to 15thDay
19%10%28%23%11%6%
288
16th to endDay
14%8%32%26%11%7%
331
June1st to 15thDay
17%9%21%30%16%3
324
16th to endDay
14%7%31%29%13%3
495
July1st to 15thDay
12%6%25%28%19%7%
414
16th to endDay
11%422%28%22%10%
326
August1st to 15thDay
8%320%27%23%15%
313
16th to endDay
17%316%20%23%18%
332
September1st to 15thDay
11%5%15%26%26%14%
315
16th to endDay
16%6%16%19%24%16%
314
October1st to 15thDay
21%8%24%23%14%6%
315
16th to endDay
25%14%31%22%5%
333
November1st to 15thDay
21%13%32%19%11%2
114
16th to endDay
30%15%34%12%5%2
90
December1st to 15thDay
25%28%30%10%5%
90
16th to endDay
32%17%39%10%
96
January1st to 15thNight
26%17%34%17%3
780
16th to endNight
20%15%38%21%3
832
February1st to 15thNight
20%19%35%21%2
764
16th to endNight
22%14%35%23%5%
659
March1st to 15thNight
22%14%34%22%5%
720
16th to endNight
18%12%32%26%9%
768
April1st to 15thNight
24%13%32%24%5%
703
16th to endNight
13%9%33%30%10%1
540
May1st to 15thNight
15%6%30%33%13%1
540
16th to endNight
12%331%33%18%
377
June1st to 15thNight
13%330%40%11%
360
16th to endNight
10%329%41%13%
360
July1st to 15thNight
4124%47%20%1
340
16th to endNight
10%222%42%21%1
551
August1st to 15thNight
6%117%44%26%2
539
16th to endNight
10%221%34%29%3
600
September1st to 15thNight
13%6%20%30%23%4
720
16th to endNight
14%419%27%26%6%
717
October1st to 15thNight
21%6%26%28%14%3
720
16th to endNight
25%11%32%24%5%
768
November1st to 15thNight
19%10%31%25%11%1
760
16th to endNight
24%17%29%20%6%1
780
December1st to 15thNight
26%18%33%17%3
780
16th to endNight
27%18%35%15%3
832
Page generated at 2018-02-23 11:21:36. Version ac04

Copyright 2018 A. Danko


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