Springwater Conservation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Springwater Conservation Area clear sky chart from 2005-11-05 to 2017-08-12.

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
38%
14831
13%
46277
10%
14794
42%
14794
18%
32642

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
14%
717
8%
2368
4%
716
19%
716
7%
1933
January16th to endNight
16%
768
8%
2496
3%
768
22%
768
9%
2013
February1st to 15thNight
17%
701
8%
2287
2%
701
24%
701
9%
1806
February16th to endNight
27%
631
10%
1957
5%
631
34%
631
13%
1491
March1st to 15thNight
27%
720
14%
2007
8%
720
32%
720
17%
1519
March16th to endNight
35%
768
19%
2112
10%
768
41%
768
23%
1473
April1st to 15thNight
31%
691
15%
1841
8%
691
37%
691
23%
1326
April16th to endNight
44%
540
20%
1620
11%
540
51%
540
26%
1042
May1st to 15thNight
45%
540
16%
1620
11%
540
50%
540
22%
1111
May16th to endNight
54%
428
17%
1551
16%
428
59%
428
25%
920
June1st to 15thNight
53%
360
14%
1434
16%
360
59%
360
24%
822
June16th to endNight
58%
360
17%
1260
16%
360
65%
360
27%
745
July1st to 15thNight
68%
387
18%
1301
22%
387
70%
387
34%
711
July16th to endNight
65%
564
15%
1595
14%
531
67%
531
34%
941
August1st to 15thNight
71%
527
17%
1575
14%
524
73%
524
34%
937
August16th to endNight
66%
540
22%
1590
16%
540
69%
540
36%
932
September1st to 15thNight
60%
660
21%
1727
14%
660
64%
660
33%
1108
September16th to endNight
58%
657
20%
1815
15%
657
61%
657
31%
1157
October1st to 15thNight
46%
660
19%
1961
17%
660
50%
660
25%
1286
October16th to endNight
26%
704
12%
2120
7%
704
32%
704
15%
1571
November1st to 15thNight
39%
700
17%
2312
14%
700
45%
700
20%
1515
November16th to endNight
24%
720
8%
2520
7%
720
26%
720
10%
1958
December1st to 15thNight
15%
720
4%
2520
3%
720
18%
720
8%
2044
December16th to endNight
16%
768
5%
2688
1%
768
20%
768
6%
2281

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%8%36%6%345%5%7%32%
47678
Night
15%8%36%5%3445%7%34%
46459
Cloud CoverDay
15%8%36%6%35%45%7%32%
47688
Night
15%8%36%5%3445%7%34%
46463
TransparencyDay
48%8%14%18%9%1
47379
Night
48%7%12%18%10%1
46277
SeeingDay
17%5%24%27%17%6%
5445
Night
19%7%27%29%14%1
14838

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%12%5%10%8%5%5%44417%
1567
16th to endDay
17%15%7%12%8%4444416%
1728
February1st to 15thDay
17%15%6%8%7%45%435%20%
1575
16th to endDay
16%11%6%10%8%46%5%6%5%19%
1515
March1st to 15thDay
17%12%5%8%7%3445%6%24%
1942
16th to endDay
17%9%6%6%7%34347%30%
2112
April1st to 15thDay
18%9%5%6%6%3446%6%28%
2117
16th to endDay
18%8%25%42435%6%37%
2340
May1st to 15thDay
17%5%36%5%35%5%5%7%34%
2331
16th to endDay
12%5%25%6%245%6%8%40%
2561
June1st to 15thDay
12%435%5%245%6%8%41%
2520
16th to endDay
11%425%435%6%6%10%39%
2700
July1st to 15thDay
9%414435%5%6%10%44%
2574
16th to endDay
9%425%5%35%6%7%10%38%
2465
August1st to 15thDay
8%415%5%36%6%7%8%39%
2288
16th to endDay
11%5%244345%6%8%43%
2248
September1st to 15thDay
13%5%26%5%35%45%7%40%
1900
16th to endDay
16%5%25%42346%7%40%
1815
October1st to 15thDay
16%6%26%6%35%5%5%6%35%
1669
16th to endDay
25%11%36%5%34446%26%
1752
November1st to 15thDay
14%7%35%435%45%6%38%
1543
16th to endDay
20%11%5%8%6%345%5%7%22%
1440
December1st to 15thDay
19%15%6%9%6%35%345%20%
1440
16th to endDay
21%15%7%11%8%4443413%
1536
January1st to 15thNight
23%12%6%10%5%35%33421%
2368
16th to endNight
16%15%8%9%7%34345%20%
2496
February1st to 15thNight
16%14%5%9%7%34446%23%
2285
16th to endNight
17%10%47%8%345%5%6%25%
1957
March1st to 15thNight
19%8%47%6%3435%8%28%
1995
16th to endNight
16%8%46%425%35%5%37%
2112
April1st to 15thNight
21%7%345%24447%33%
1841
16th to endNight
11%5%45%5%35%45%7%41%
1620
May1st to 15thNight
15%6%35%5%346%6%8%34%
1620
16th to endNight
10%5%24325%5%5%7%46%
1549
June1st to 15thNight
11%4343345%6%9%43%
1434
16th to endNight
10%413435%5%6%9%45%
1260
July1st to 15thNight
5%4245%23348%55%
1380
16th to endNight
8%3234345%6%9%48%
1703
August1st to 15thNight
6%3135%345%7%10%48%
1586
16th to endNight
9%42442335%8%53%
1590
September1st to 15thNight
11%42343445%7%47%
1727
16th to endNight
13%3145%25%5%5%7%46%
1815
October1st to 15thNight
16%5%24334446%43%
1961
16th to endNight
21%8%36%5%2445%6%30%
2120
November1st to 15thNight
13%6%345%25%47%6%39%
2312
16th to endNight
23%10%37%5%245%5%6%24%
2520
December1st to 15thNight
21%13%5%7%5%34447%21%
2520
16th to endNight
21%14%6%8%7%35%446%17%
2688

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%12%5%9%9%46%345%17%
1567
16th to endDay
16%16%6%12%8%45%44416%
1728
February1st to 15thDay
17%15%5%9%7%45%435%19%
1575
16th to endDay
16%12%6%10%7%45%5%5%6%19%
1515
March1st to 15thDay
17%11%6%7%7%3435%5%24%
1953
16th to endDay
17%9%6%6%6%25%346%30%
2111
April1st to 15thDay
18%9%5%6%5%3445%6%28%
2117
16th to endDay
17%9%34424347%37%
2340
May1st to 15thDay
17%6%25%6%26%5%6%7%34%
2331
16th to endDay
12%5%26%5%245%5%9%40%
2561
June1st to 15thDay
12%5%26%5%25%5%6%8%40%
2520
16th to endDay
10%4245%25%6%8%10%39%
2700
July1st to 15thDay
9%414425%5%6%10%44%
2574
16th to endDay
8%4245%36%5%8%10%39%
2465
August1st to 15thDay
8%5%246%45%7%7%9%39%
2288
16th to endDay
11%4244345%6%9%42%
2248
September1st to 15thDay
12%5%26%6%4446%8%38%
1900
16th to endDay
15%5%25%43446%7%40%
1815
October1st to 15thDay
15%6%36%6%36%5%5%6%35%
1669
16th to endDay
25%9%46%6%24346%25%
1752
November1st to 15thDay
14%6%35%6%35%35%6%38%
1543
16th to endDay
20%12%49%5%35%5%5%6%22%
1440
December1st to 15thDay
20%15%6%10%6%34345%19%
1440
16th to endDay
22%14%7%11%7%445%3414%
1536
January1st to 15thNight
23%12%6%9%6%35%43421%
2368
16th to endNight
16%15%8%9%7%34446%20%
2496
February1st to 15thNight
16%13%5%10%7%44446%23%
2278
16th to endNight
17%10%5%8%6%35%5%5%6%26%
1957
March1st to 15thNight
20%8%46%6%3435%7%28%
2007
16th to endNight
16%8%35%5%3445%5%37%
2112
April1st to 15thNight
20%7%45%434447%33%
1841
16th to endNight
11%6%35%5%345%5%6%41%
1620
May1st to 15thNight
15%7%35%5%35%47%7%34%
1619
16th to endNight
11%5%245%25%45%7%45%
1549
June1st to 15thNight
11%425%3345%7%9%42%
1434
16th to endNight
9%5%234345%6%8%45%
1260
July1st to 15thNight
5%324433448%54%
1380
16th to endNight
8%423435%46%8%48%
1703
August1st to 15thNight
5%435%445%8%10%47%
1586
16th to endNight
9%423423447%52%
1590
September1st to 15thNight
11%42443445%8%46%
1727
16th to endNight
12%3135%245%6%7%46%
1815
October1st to 15thNight
16%5%35%424446%42%
1961
16th to endNight
21%8%36%5%2445%7%30%
2120
November1st to 15thNight
13%5%35%5%25%5%6%7%39%
2312
16th to endNight
22%10%37%5%245%5%7%24%
2520
December1st to 15thNight
22%13%5%8%5%34447%21%
2520
16th to endNight
22%13%6%9%7%35%45%5%17%
2688

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
69%6%10%10%2
1568
16th to endDay
71%6%11%8%3
1728
February1st to 15thDay
67%5%11%12%3
1577
16th to endDay
63%7%12%12%3
1515
March1st to 15thDay
60%6%12%13%6%
1953
16th to endDay
54%411%18%9%1
2112
April1st to 15thDay
53%6%11%18%9%
2117
16th to endDay
45%5%12%18%15%2
2340
May1st to 15thDay
46%7%13%20%11%1
2331
16th to endDay
38%9%15%22%13%1
2565
June1st to 15thDay
38%8%15%23%13%1
2520
16th to endDay
35%11%16%21%14%
2700
July1st to 15thDay
32%7%15%24%17%2
2425
16th to endDay
34%10%17%21%13%1
2310
August1st to 15thDay
35%11%17%21%12%1
2275
16th to endDay
35%8%18%24%11%2
2248
September1st to 15thDay
40%9%16%23%10%
1900
16th to endDay
40%6%16%23%11%
1815
October1st to 15thDay
47%8%14%16%12%1
1669
16th to endDay
59%7%15%12%4
1752
November1st to 15thDay
45%8%16%18%8%1
1543
16th to endDay
61%9%14%11%3
1440
December1st to 15thDay
67%10%12%7%1
1440
16th to endDay
74%7%9%7%
1536
January1st to 15thNight
66%7%9%10%5%
2368
16th to endNight
65%6%12%12%2
2496
February1st to 15thNight
63%6%13%12%4
2287
16th to endNight
57%7%13%15%4
1957
March1st to 15thNight
55%6%11%19%6%1
2007
16th to endNight
47%5%11%21%12%2
2112
April1st to 15thNight
50%410%20%12%1
1841
16th to endNight
40%6%10%20%18%3
1620
May1st to 15thNight
46%6%11%20%12%2
1620
16th to endNight
36%7%12%23%16%3
1551
June1st to 15thNight
35%7%14%26%14%1
1434
16th to endNight
35%6%13%24%17%1
1260
July1st to 15thNight
29%6%9%28%21%4
1301
16th to endNight
31%7%15%23%18%2
1595
August1st to 15thNight
27%10%15%28%14%2
1575
16th to endNight
29%7%13%28%17%2
1590
September1st to 15thNight
34%7%14%25%16%2
1727
16th to endNight
35%8%13%27%14%
1815
October1st to 15thNight
41%6%13%21%16%
1961
16th to endNight
53%7%14%15%7%
2120
November1st to 15thNight
42%8%15%20%11%1
2312
16th to endNight
58%10%14%12%3
2520
December1st to 15thNight
63%9%14%8%2
2520
16th to endNight
69%9%11%8%2
2688

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%19%39%10%9%1
83
16th to endDay
29%10%41%18%
96
February1st to 15thDay
21%14%54%10%
90
16th to endDay
17%12%48%20%1
81
March1st to 15thDay
25%10%28%28%7%
243
16th to endDay
24%5%32%26%8%1
288
April1st to 15thDay
24%9%30%24%10%1
270
16th to endDay
21%5%26%25%13%7%
270
May1st to 15thDay
23%425%25%17%3
288
16th to endDay
14%324%31%19%6%
331
June1st to 15thDay
13%323%35%20%3
315
16th to endDay
12%225%36%18%4
495
July1st to 15thDay
12%118%33%25%8%
409
16th to endDay
10%17%30%30%10%
326
August1st to 15thDay
11%113%27%31%14%
297
16th to endDay
12%114%25%27%18%
268
September1st to 15thDay
13%213%24%29%16%
255
16th to endDay
19%316%24%21%14%
254
October1st to 15thDay
18%7%22%26%20%5%
255
16th to endDay
29%8%32%23%6%
264
November1st to 15thDay
10%13%26%32%13%3
83
16th to endDay
23%25%25%20%5%1
60
December1st to 15thDay
30%23%31%10%5%
60
16th to endDay
25%32%32%7%1
64
January1st to 15thNight
28%15%35%15%4
720
16th to endNight
23%12%37%21%5%
768
February1st to 15thNight
24%13%35%23%4
704
16th to endNight
23%8%33%29%5%
631
March1st to 15thNight
23%7%34%26%8%
720
16th to endNight
21%432%29%11%1
768
April1st to 15thNight
23%8%30%30%7%
691
16th to endNight
16%429%34%12%2
540
May1st to 15thNight
17%323%35%17%1
540
16th to endNight
14%123%37%19%3
429
June1st to 15thNight
13%223%40%19%1
360
16th to endNight
11%121%45%19%1
360
July1st to 15thNight
6%18%41%28%4
387
16th to endNight
9%114%43%27%3
564
August1st to 15thNight
8%12%39%33%4
527
16th to endNight
10%214%33%34%5%
540
September1st to 15thNight
13%414%32%29%6%
660
16th to endNight
13%418%30%26%7%
657
October1st to 15thNight
18%6%20%32%18%3
660
16th to endNight
23%11%32%25%6%
704
November1st to 15thNight
15%9%30%29%13%1
700
16th to endNight
28%12%29%18%9%1
720
December1st to 15thNight
30%15%34%15%3
720
16th to endNight
27%12%35%20%3
768
Page generated at 2017-08-13 14:16:53. Version ac04

Copyright 2017 A. Danko


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