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 2005-11-06 to 2024-01-31.

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
36%
23116
13%
74702
10%
23064
41%
23064
17%
53038

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 10thNight
13%
758
9%
2526
4%
757
19%
757
8%
2026
January11th to 20thNight
14%
760
5%
2470
3%
760
17%
760
7%
2057
January21st to endNight
19%
835
9%
2711
4%
835
25%
835
10%
2162
February1st to 10thNight
16%
720
7%
2340
2%
720
22%
720
9%
1870
February11th to 20thNight
22%
700
10%
2274
4%
699
28%
699
12%
1719
February21st to endNight
20%
592
11%
1782
4%
592
29%
592
13%
1379
March1st to 10thNight
26%
720
16%
2020
9%
720
33%
720
19%
1462
March11th to 20thNight
29%
720
18%
1980
9%
720
36%
720
20%
1410
March21st to endNight
32%
792
17%
2178
9%
792
38%
792
20%
1576
April1st to 10thNight
30%
720
14%
1908
7%
720
35%
720
22%
1368
April11th to 20thNight
35%
583
18%
1647
9%
583
41%
583
24%
1128
April21st to endNight
38%
540
17%
1620
8%
540
45%
540
22%
1096
May1st to 10thNight
42%
540
14%
1620
10%
540
46%
540
22%
1106
May11th to 20thNight
47%
527
17%
1589
12%
527
53%
527
25%
1043
May21st to endNight
57%
388
17%
1551
19%
388
62%
388
27%
855
June1st to 10thNight
53%
360
15%
1440
18%
360
60%
360
25%
819
June11th to 20thNight
54%
360
17%
1343
18%
360
62%
360
26%
774
June21st to endNight
56%
360
20%
1260
20%
360
65%
360
28%
737
July1st to 10thNight
69%
350
19%
1238
25%
350
72%
350
34%
661
July11th to 20thNight
63%
509
17%
1553
17%
509
66%
509
33%
915
July21st to endNight
64%
591
16%
1672
13%
558
66%
558
32%
1003
August1st to 10thNight
69%
537
18%
1600
16%
534
71%
534
34%
966
August11th to 20thNight
68%
534
22%
1598
17%
534
71%
534
34%
939
August21st to endNight
62%
618
22%
1806
15%
618
66%
618
33%
1086
September1st to 10thNight
56%
720
18%
1836
10%
720
60%
720
32%
1210
September11th to 20thNight
65%
720
25%
1980
19%
720
68%
720
37%
1179
September21st to endNight
49%
720
19%
1980
14%
720
53%
720
26%
1334
October1st to 10thNight
46%
720
18%
2128
16%
720
50%
720
25%
1399
October11th to 20thNight
32%
720
14%
2160
10%
720
39%
720
18%
1532
October21st to endNight
26%
792
14%
2387
10%
792
32%
792
14%
1769
November1st to 10thNight
39%
740
19%
2406
14%
740
45%
740
22%
1546
November11th to 20thNight
23%
760
13%
2623
7%
760
31%
760
13%
1894
November21st to endNight
23%
760
8%
2660
6%
760
26%
760
10%
2066
December1st to 10thNight
17%
760
5%
2660
3%
760
20%
760
8%
2122
December11th to 20thNight
15%
760
5%
3274
2%
759
21%
759
6%
2604
December21st to endNight
15%
830
4%
4882
2%
817
20%
817
3%
4226

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%6%7%33%
75203
Night
16%9%47%6%35%5%5%7%34%
74902
TransparencyDay
48%9%14%18%10%1
74922
Night
49%8%13%18%10%1
74719
SeeingDay
17%9%27%27%15%5%
13818
Night
19%9%28%29%13%2
23128

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 10thDay
17%14%6%10%9%6%6%5%4420%
1635
11th to 20thDay
17%17%6%13%7%5%5%45%5%16%
1710
21st to endDay
18%16%7%11%9%445%5%416%
1872
February1st to 10thDay
18%16%6%9%9%46%45%5%18%
1620
11th to 20thDay
16%11%7%11%8%46%5%46%21%
1573
21st to endDay
19%12%5%10%6%5%5%5%6%5%23%
1471
March1st to 10thDay
16%12%48%8%36%45%6%27%
1936
11th to 20thDay
14%12%6%9%7%43447%30%
1980
21st to endDay
20%9%6%7%8%34346%29%
2178
April1st to 10thDay
16%10%5%7%6%35%46%7%30%
2052
11th to 20thDay
17%10%46%6%3446%8%33%
2277
21st to endDay
20%8%37%5%3445%6%34%
2340
May1st to 10thDay
17%6%37%6%35%5%6%7%34%
2340
11th to 20thDay
17%7%45%5%35%5%6%6%36%
2301
21st to endDay
11%5%35%6%346%7%9%43%
2725
June1st to 10thDay
12%5%35%6%346%6%8%41%
2520
11th to 20thDay
11%6%26%5%35%6%6%9%40%
2610
21st to endDay
11%435%4346%6%10%43%
2700
July1st to 10thDay
8%5%24435%6%6%10%48%
2682
11th to 20thDay
11%5%25%5%35%6%8%10%40%
2350
21st to endDay
9%5%36%6%36%7%7%10%39%
2547
August1st to 10thDay
9%425%5%45%7%7%9%43%
2327
11th to 20thDay
10%6%25%6%46%6%8%10%37%
2303
21st to endDay
10%6%25%5%445%6%8%44%
2531
September1st to 10thDay
11%5%26%5%35%5%6%9%42%
2121
11th to 20thDay
10%425%5%345%6%8%46%
1980
21st to endDay
16%7%35%5%345%7%7%38%
1980
October1st to 10thDay
16%7%26%6%35%5%6%7%37%
1831
11th to 20thDay
18%10%36%6%45%6%5%7%30%
1800
21st to endDay
24%10%38%6%445%46%25%
1967
November1st to 10thDay
14%8%36%6%45%6%6%7%35%
1672
11th to 20thDay
16%10%5%7%5%445%5%8%31%
1554
21st to endDay
20%14%5%8%7%45%5%5%6%21%
1520
December1st to 10thDay
17%15%6%10%7%35%45%7%21%
1520
11th to 20thDay
19%15%7%9%8%45%5%5%6%18%
1906
21st to endDay
29%18%5%10%6%34445%11%
2772
January1st to 10thNight
19%12%6%11%7%45%5%45%22%
2526
11th to 20thNight
21%18%6%9%6%35%5%45%18%
2470
21st to endNight
16%13%8%10%8%4445%6%21%
2711
February1st to 10thNight
18%15%5%9%8%345%5%6%21%
2340
11th to 20thNight
17%12%5%9%7%445%5%7%26%
2273
21st to endNight
19%12%48%7%35%6%5%6%24%
1782
March1st to 10thNight
16%8%47%7%45%45%8%31%
2010
11th to 20thNight
16%9%47%6%35%45%7%35%
1979
21st to endNight
18%10%47%6%345%45%34%
2178
April1st to 10thNight
19%8%35%6%35%45%7%35%
1908
11th to 20thNight
17%7%46%5%35%45%7%37%
1647
21st to endNight
15%6%46%6%45%5%5%6%37%
1620
May1st to 10thNight
18%7%35%5%346%6%8%35%
1620
11th to 20thNight
14%6%36%6%36%5%5%7%40%
1588
21st to endNight
10%5%24435%6%6%7%49%
1550
June1st to 10thNight
12%4344345%7%8%45%
1440
11th to 20thNight
10%5%14445%6%8%10%44%
1343
21st to endNight
11%5%23445%5%5%8%47%
1260
July1st to 10thNight
6%5%145%33449%56%
1273
11th to 20thNight
10%424435%45%9%49%
1606
21st to endNight
8%5%25%5%35%5%7%8%47%
1771
August1st to 10thNight
7%4246%35%6%7%9%48%
1611
11th to 20thNight
7%4245%3438%9%50%
1598
21st to endNight
9%5%2443446%9%49%
1806
September1st to 10thNight
10%6%35%5%345%5%8%46%
1836
11th to 20thNight
10%42443445%7%53%
1980
21st to endNight
15%5%25%5%36%5%6%7%42%
1980
October1st to 10thNight
14%6%26%5%35%45%7%43%
2128
11th to 20thNight
18%9%37%5%345%5%5%36%
2160
21st to endNight
23%8%47%5%45%447%30%
2387
November1st to 10thNight
15%6%35%5%25%47%6%41%
2406
11th to 20thNight
16%9%36%7%45%5%6%7%32%
2623
21st to endNight
22%11%47%6%35%5%6%7%25%
2660
December1st to 10thNight
20%13%5%9%6%3445%7%23%
2660
11th to 20thNight
16%18%6%8%6%35%5%5%6%23%
3288
21st to endNight
28%18%6%8%7%3444414%
4884

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 10thDay
66%8%11%11%3
1636
11th to 20thDay
68%9%11%8%4
1710
21st to endDay
70%6%11%8%5%1
1872
February1st to 10thDay
67%7%13%10%31
1620
11th to 20thDay
63%7%10%13%6%
1582
21st to endDay
60%8%12%13%5%1
1471
March1st to 10thDay
56%7%14%15%7%1
1939
11th to 20thDay
54%7%11%17%9%2
1980
21st to endDay
57%5%9%18%10%1
2178
April1st to 10thDay
51%7%12%19%11%1
2052
11th to 20thDay
48%7%12%18%13%1
2277
21st to endDay
49%7%13%17%12%2
2340
May1st to 10thDay
45%8%15%18%11%2
2340
11th to 20thDay
45%8%13%19%13%2
2305
21st to endDay
34%10%17%22%15%2
2725
June1st to 10thDay
38%9%14%24%13%2
2520
11th to 20thDay
37%10%16%20%15%1
2610
21st to endDay
33%10%16%25%16%1
2700
July1st to 10thDay
30%9%15%25%18%3
2609
11th to 20thDay
34%9%19%24%14%1
2280
21st to endDay
33%11%18%23%14%1
2405
August1st to 10thDay
32%11%18%27%11%1
2314
11th to 20thDay
35%12%19%23%10%1
2303
21st to endDay
35%9%17%24%13%2
2531
September1st to 10thDay
36%10%18%22%12%1
2121
11th to 20thDay
32%9%18%28%14%
1980
21st to endDay
42%8%15%22%11%1
1980
October1st to 10thDay
44%8%16%18%12%1
1831
11th to 20thDay
51%11%14%16%7%1
1800
21st to endDay
59%8%13%13%6%
1967
November1st to 10thDay
46%10%15%20%7%2
1672
11th to 20thDay
49%10%18%13%8%1
1554
21st to endDay
63%10%13%11%3
1520
December1st to 10thDay
63%13%12%10%2
1520
11th to 20thDay
65%11%13%9%2
1906
21st to endDay
75%10%10%5%1
2772
January1st to 10thNight
64%9%12%12%4
2526
11th to 20thNight
68%8%11%9%3
2470
21st to endNight
63%8%12%12%5%1
2711
February1st to 10thNight
63%8%12%12%4
2340
11th to 20thNight
58%7%14%14%6%
2275
21st to endNight
58%8%12%16%6%1
1782
March1st to 10thNight
50%7%13%20%9%1
2020
11th to 20thNight
48%7%10%21%11%2
1980
21st to endNight
51%6%10%19%12%3
2178
April1st to 10thNight
48%7%12%19%13%2
1908
11th to 20thNight
45%6%11%19%17%2
1647
21st to endNight
44%8%12%19%15%3
1620
May1st to 10thNight
46%7%11%18%14%4
1620
11th to 20thNight
43%6%12%20%15%4
1589
21st to endNight
31%9%14%25%18%3
1551
June1st to 10thNight
35%8%13%26%15%3
1440
11th to 20thNight
33%9%15%23%18%2
1343
21st to endNight
35%7%14%26%18%1
1260
July1st to 10thNight
27%8%11%28%21%5%
1238
11th to 20thNight
32%7%12%28%17%3
1553
21st to endNight
31%9%17%22%18%3
1672
August1st to 10thNight
29%11%16%30%14%1
1600
11th to 20thNight
29%10%16%30%14%2
1598
21st to endNight
30%9%15%27%16%2
1806
September1st to 10thNight
37%7%15%24%15%2
1836
11th to 20thNight
29%7%15%30%17%1
1980
21st to endNight
41%8%13%24%13%1
1980
October1st to 10thNight
40%8%13%23%16%1
2128
11th to 20thNight
48%8%14%19%11%
2160
21st to endNight
54%8%13%16%9%1
2387
November1st to 10thNight
40%9%15%23%12%1
2406
11th to 20thNight
50%11%14%16%7%1
2623
21st to endNight
57%11%16%12%31
2660
December1st to 10thNight
62%10%16%10%3
2660
11th to 20thNight
61%12%14%10%3
3288
21st to endNight
73%10%10%6%1
4884

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 10thDay
23%18%30%20%6%2
236
11th to 20thDay
26%12%43%13%5%2
270
21st to endDay
25%16%34%20%41
294
February1st to 10thDay
21%18%43%17%1
240
11th to 20thDay
24%18%38%19%2
240
21st to endDay
22%26%39%12%2
198
March1st to 10thDay
22%13%36%23%6%
379
11th to 20thDay
19%13%34%27%5%1
420
21st to endDay
27%12%32%21%7%
462
April1st to 10thDay
18%12%37%24%9%1
420
11th to 20thDay
22%13%30%20%11%4
412
21st to endDay
22%10%29%28%9%2
420
May1st to 10thDay
21%10%29%24%12%3
423
11th to 20thDay
19%8%24%28%18%4
447
21st to endDay
12%421%32%23%7%
485
June1st to 10thDay
12%329%37%16%3
450
11th to 20thDay
11%6%21%36%21%4
540
21st to endDay
12%327%36%19%3
630
July1st to 10thDay
7%318%33%28%10%
604
11th to 20thDay
14%321%30%22%9%
444
21st to endDay
8%317%40%25%7%
488
August1st to 10thDay
8%216%32%28%14%
446
11th to 20thDay
11%413%35%25%12%
439
21st to endDay
11%317%32%28%10%
495
September1st to 10thDay
12%320%31%22%11%
450
11th to 20thDay
7%318%26%30%14%
450
21st to endDay
15%8%25%26%17%8%
450
October1st to 10thDay
19%8%26%20%21%6%
450
11th to 20thDay
20%14%31%26%7%2
450
21st to endDay
26%12%34%22%6%
482
November1st to 10thDay
16%19%30%23%10%3
270
11th to 20thDay
22%21%28%19%7%2
196
21st to endDay
24%17%38%18%2
180
December1st to 10thDay
28%18%32%15%6%1
180
11th to 20thDay
26%23%33%15%3
180
21st to endDay
26%20%35%15%3
198
January1st to 10thNight
24%16%37%15%6%1
760
11th to 20thNight
29%16%33%19%4
760
21st to endNight
21%10%38%24%6%
835
February1st to 10thNight
26%13%36%22%3
720
11th to 20thNight
22%13%34%26%4
703
21st to endNight
24%11%39%23%3
592
March1st to 10thNight
20%8%38%27%7%
720
11th to 20thNight
20%9%35%27%7%1
720
21st to endNight
23%8%30%29%10%1
792
April1st to 10thNight
21%10%33%30%6%
720
11th to 20thNight
20%10%31%27%11%1
583
21st to endNight
21%431%33%10%1
540
May1st to 10thNight
19%5%26%32%16%1
540
11th to 20thNight
17%325%40%13%2
527
21st to endNight
13%321%37%25%3
389
June1st to 10thNight
15%322%42%18%1
360
11th to 20thNight
12%225%41%19%
360
21st to endNight
11%423%43%19%1
360
July1st to 10thNight
6%117%41%31%4
350
11th to 20thNight
10%316%40%27%5%
509
21st to endNight
10%216%45%25%2
591
August1st to 10thNight
8%212%40%33%4
537
11th to 20thNight
9%214%34%37%4
534
21st to endNight
10%318%39%27%4
618
September1st to 10thNight
12%5%18%32%27%6%
720
11th to 20thNight
11%414%36%31%5%
720
21st to endNight
15%6%23%32%18%6%
720
October1st to 10thNight
17%6%24%32%18%4
720
11th to 20thNight
21%13%28%27%11%1
720
21st to endNight
25%11%32%27%5%
792
November1st to 10thNight
17%11%27%30%13%1
740
11th to 20thNight
21%14%35%20%7%2
760
21st to endNight
26%13%33%21%7%
760
December1st to 10thNight
28%17%33%17%5%1
760
11th to 20thNight
24%18%36%18%4
760
21st to endNight
29%13%33%22%2
836
Page generated at 2024-01-28 05:26:31. Version ac07

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