Center Hill Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Center Hill Lake clear sky chart from 2005-11-06 to 2024-02-20.

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
44%
23732
20%
79634
15%
23622
50%
23622
23%
51445

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
21%
755
18%
4032
10%
737
33%
737
11%
2647
January11th to 20thNight
19%
759
19%
3994
8%
740
28%
740
8%
2728
January21st to endNight
19%
834
14%
4307
9%
814
32%
814
11%
2989
February1st to 10thNight
23%
760
18%
2280
9%
760
31%
760
18%
1637
February11th to 20thNight
16%
742
15%
2214
7%
739
24%
739
16%
1603
February21st to endNight
17%
592
18%
1776
8%
592
26%
592
15%
1299
March1st to 10thNight
27%
720
19%
2160
9%
720
35%
720
21%
1451
March11th to 20thNight
25%
720
17%
2014
8%
720
33%
720
19%
1431
March21st to endNight
32%
779
17%
2165
9%
779
37%
779
21%
1502
April1st to 10thNight
39%
540
26%
1800
17%
540
51%
540
27%
1060
April11th to 20thNight
38%
533
26%
1775
17%
533
51%
533
28%
1050
April21st to endNight
41%
540
22%
1701
14%
540
49%
540
27%
1057
May1st to 10thNight
43%
540
20%
1620
11%
540
51%
540
29%
1015
May11th to 20thNight
53%
531
17%
1593
12%
531
56%
531
27%
1029
May21st to endNight
63%
582
17%
1745
13%
582
66%
582
29%
1109
June1st to 10thNight
65%
540
18%
1620
16%
540
67%
540
32%
989
June11th to 20thNight
73%
540
20%
1620
17%
540
75%
540
41%
891
June21st to endNight
71%
540
19%
1506
15%
540
72%
540
34%
939
July1st to 10thNight
68%
525
13%
1503
11%
525
68%
525
27%
1012
July11th to 20thNight
71%
522
17%
1566
16%
522
73%
522
32%
949
July21st to endNight
73%
591
18%
1672
17%
558
75%
558
28%
1088
August1st to 10thNight
72%
537
19%
1612
18%
534
72%
534
30%
1007
August11th to 20thNight
70%
534
16%
1776
18%
534
71%
534
28%
1089
August21st to endNight
72%
594
20%
1980
23%
594
72%
594
30%
1168
September1st to 10thNight
66%
600
20%
1860
20%
600
66%
600
28%
1153
September11th to 20thNight
61%
720
23%
1980
20%
720
62%
720
30%
1290
September21st to endNight
61%
720
29%
1980
21%
720
66%
720
38%
1166
October1st to 10thNight
60%
720
32%
1980
27%
720
64%
720
40%
1132
October11th to 20thNight
45%
720
28%
2024
20%
720
53%
720
31%
1250
October21st to endNight
43%
792
28%
2524
23%
792
52%
792
29%
1526
November1st to 10thNight
50%
740
27%
2406
26%
740
57%
740
31%
1381
November11th to 20thNight
37%
760
28%
2470
19%
760
51%
760
30%
1435
November21st to endNight
36%
760
24%
2470
16%
760
46%
760
25%
1542
December1st to 10thNight
28%
760
17%
2470
11%
760
35%
760
15%
1779
December11th to 20thNight
31%
759
21%
2974
15%
759
41%
759
17%
1936
December21st to endNight
23%
831
12%
4465
10%
817
34%
817
9%
3116

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
14%7%36%5%35%5%6%7%38%
78927
Night
15%8%35%5%3445%7%40%
80230
TransparencyDay
44%7%11%20%15%3
78650
Night
42%6%10%21%17%3
80026
SeeingDay
18%11%22%23%18%9%
13760
Night
18%9%23%28%19%3
23748

By Month

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 10thDay
17%13%6%9%6%45%6%45%26%
2836
11th to 20thDay
22%10%6%11%5%35%335%28%
2840
21st to endDay
25%13%5%5%42345%5%29%
3293
February1st to 10thDay
21%11%5%7%5%24345%34%
1900
11th to 20thDay
22%10%47%5%34346%31%
1838
21st to endDay
23%9%45%5%34446%34%
1480
March1st to 10thDay
15%9%36%5%44446%39%
1800
11th to 20thDay
20%9%47%5%35%446%33%
1944
21st to endDay
17%9%46%5%35%5%6%7%34%
2204
April1st to 10thDay
13%5%36%5%25%46%6%45%
2160
11th to 20thDay
15%7%35%5%3445%7%43%
2134
21st to endDay
14%7%36%6%445%6%6%40%
2258
May1st to 10thDay
15%6%245%345%6%8%42%
2340
11th to 20thDay
14%7%36%6%47%45%7%37%
2301
21st to endDay
9%5%36%6%46%5%7%9%39%
2531
June1st to 10thDay
10%6%35%5%46%5%6%10%41%
2340
11th to 20thDay
5%425%6%35%6%7%10%45%
2340
21st to endDay
6%326%6%47%6%9%12%39%
2432
July1st to 10thDay
9%6%37%6%5%7%7%9%10%34%
2394
11th to 20thDay
10%436%7%46%7%7%10%35%
2340
21st to endDay
9%5%35%7%5%6%6%7%12%34%
2547
August1st to 10thDay
8%6%35%5%47%8%9%10%34%
2310
11th to 20thDay
9%6%36%7%47%7%7%10%35%
2125
21st to endDay
11%5%25%7%47%7%7%10%35%
2376
September1st to 10thDay
13%6%35%6%35%5%7%8%39%
2080
11th to 20thDay
15%6%36%43445%7%43%
1980
21st to endDay
11%5%35%43446%6%50%
1980
October1st to 10thDay
11%4245%3435%7%53%
1980
11th to 20thDay
13%4245%33346%52%
1935
21st to endDay
17%6%24434446%46%
1830
November1st to 10thDay
12%423424446%55%
1672
11th to 20thDay
16%6%2433345%6%48%
1710
21st to endDay
16%9%3443435%5%44%
1710
December1st to 10thDay
22%11%36%5%24446%32%
1710
11th to 20thDay
17%11%37%5%345%5%6%33%
2153
21st to endDay
19%14%46%5%34447%28%
3124
January1st to 10thNight
18%15%46%423447%32%
4109
11th to 20thNight
21%12%46%7%3334433%
4120
21st to endNight
21%15%36%5%34335%31%
4359
February1st to 10thNight
22%10%37%43445%7%31%
2280
11th to 20thNight
24%8%47%5%33345%33%
2213
21st to endNight
25%12%36%424347%30%
1776
March1st to 10thNight
17%7%35%5%2445%7%39%
2160
11th to 20thNight
19%9%37%5%35%446%36%
2014
21st to endNight
16%9%36%5%45%5%5%7%36%
2165
April1st to 10thNight
12%6%25%435%45%8%46%
1800
11th to 20thNight
16%5%25%32445%7%47%
1775
21st to endNight
14%6%25%5%35%45%8%43%
1701
May1st to 10thNight
12%5%35%5%345%6%7%45%
1620
11th to 20thNight
11%5%25%436%5%6%8%44%
1592
21st to endNight
7%426%6%36%6%7%11%42%
1744
June1st to 10thNight
6%5%36%5%445%6%10%46%
1620
11th to 20thNight
5%2235%25%5%7%13%52%
1620
21st to endNight
6%325%5%37%5%8%12%45%
1506
July1st to 10thNight
9%6%36%6%46%6%8%10%38%
1548
11th to 20thNight
7%434446%6%7%12%42%
1620
21st to endNight
7%5%26%5%5%7%8%8%12%37%
1771
August1st to 10thNight
6%435%6%46%5%7%10%42%
1623
11th to 20thNight
8%5%25%5%35%6%8%10%42%
1776
21st to endNight
9%4245%35%6%8%11%44%
1980
September1st to 10thNight
11%5%35%5%346%6%8%45%
1860
11th to 20thNight
11%6%26%6%345%5%7%44%
1980
21st to endNight
10%5%2443345%7%53%
1980
October1st to 10thNight
10%5%14323448%57%
1980
11th to 20thNight
16%6%2442245%7%47%
2024
21st to endNight
16%8%25%422446%47%
2524
November1st to 10thNight
12%6%24434347%51%
2406
11th to 20thNight
14%7%2432335%7%49%
2470
21st to endNight
17%8%4442435%7%43%
2470
December1st to 10thNight
21%11%46%43445%6%31%
2470
11th to 20thNight
18%10%37%423346%39%
3042
21st to endNight
17%14%47%7%45%5%5%7%27%
4532

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
57%6%6%17%12%2
2837
11th to 20thDay
58%5%5%14%15%1
2840
21st to endDay
57%5%7%20%10%1
3293
February1st to 10thDay
55%47%16%16%2
1900
11th to 20thDay
55%5%7%17%13%4
1848
21st to endDay
53%5%9%13%15%5%
1480
March1st to 10thDay
47%48%18%18%5%
1800
11th to 20thDay
53%6%9%16%14%3
1944
21st to endDay
49%7%11%19%13%1
2204
April1st to 10thDay
38%6%12%23%17%3
2160
11th to 20thDay
41%5%7%20%23%4
2134
21st to endDay
42%7%10%26%14%2
2258
May1st to 10thDay
39%9%11%26%13%2
2340
11th to 20thDay
46%8%12%20%13%1
2305
21st to endDay
40%10%13%21%14%2
2531
June1st to 10thDay
38%9%14%24%14%2
2340
11th to 20thDay
31%11%18%22%16%2
2340
21st to endDay
34%11%18%19%14%4
2432
July1st to 10thDay
41%12%15%18%10%3
2329
11th to 20thDay
42%11%16%18%10%3
2271
21st to endDay
39%12%17%22%9%1
2405
August1st to 10thDay
39%13%19%19%9%1
2297
11th to 20thDay
42%11%14%19%13%2
2125
21st to endDay
42%11%14%19%12%2
2376
September1st to 10thDay
41%9%12%19%15%4
2080
11th to 20thDay
41%7%12%21%17%2
1980
21st to endDay
34%6%10%25%20%5%
1980
October1st to 10thDay
32%6%9%21%26%6%
1980
11th to 20thDay
32%6%8%22%25%7%
1935
21st to endDay
39%5%7%21%23%5%
1830
November1st to 10thDay
31%48%24%28%5%
1672
11th to 20thDay
38%46%24%22%6%
1710
21st to endDay
42%47%22%21%4
1710
December1st to 10thDay
54%45%21%13%2
1710
11th to 20thDay
51%5%8%18%15%2
2150
21st to endDay
53%6%10%20%9%2
3124
January1st to 10thNight
51%5%8%20%15%2
4109
11th to 20thNight
55%5%6%13%16%5%
4120
21st to endNight
55%5%8%16%15%1
4359
February1st to 10thNight
53%48%18%15%1
2280
11th to 20thNight
55%47%17%13%4
2214
21st to endNight
55%5%8%15%13%4
1776
March1st to 10thNight
45%6%9%15%19%7%
2160
11th to 20thNight
49%6%8%21%14%2
2014
21st to endNight
46%7%10%23%12%2
2165
April1st to 10thNight
36%6%10%25%21%3
1800
11th to 20thNight
36%5%9%21%22%7%
1775
21st to endNight
39%5%11%28%15%1
1701
May1st to 10thNight
36%7%12%24%17%2
1620
11th to 20thNight
37%10%17%22%14%1
1593
21st to endNight
34%11%16%22%14%3
1745
June1st to 10thNight
35%7%15%28%14%2
1620
11th to 20thNight
22%10%20%31%15%3
1620
21st to endNight
29%12%17%26%13%4
1506
July1st to 10thNight
38%11%17%19%13%3
1503
11th to 20thNight
30%11%19%22%14%5%
1566
21st to endNight
34%12%17%24%11%2
1672
August1st to 10thNight
34%10%17%27%12%
1612
11th to 20thNight
34%10%20%19%15%2
1776
21st to endNight
33%8%17%25%14%3
1980
September1st to 10thNight
36%8%14%22%16%5%
1860
11th to 20thNight
37%8%11%19%23%2
1980
21st to endNight
31%5%11%23%25%5%
1980
October1st to 10thNight
28%5%7%23%28%8%
1980
11th to 20thNight
36%5%8%21%22%7%
2024
21st to endNight
38%46%22%24%6%
2524
November1st to 10thNight
34%46%23%25%7%
2406
11th to 20thNight
36%48%21%25%7%
2470
21st to endNight
42%37%23%20%4
2470
December1st to 10thNight
54%6%7%17%13%2
2470
11th to 20thNight
46%5%7%19%19%3
3044
21st to endNight
55%6%9%18%11%1
4532

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
26%22%37%10%41
270
11th to 20thDay
36%24%23%12%5%
270
21st to endDay
24%24%37%12%3
297
February1st to 10thDay
29%23%30%14%4
270
11th to 20thDay
38%22%31%6%3
267
21st to endDay
35%23%31%10%2
198
March1st to 10thDay
23%22%36%14%4
240
11th to 20thDay
26%21%31%15%7%1
384
21st to endDay
28%16%30%18%8%
462
April1st to 10thDay
19%20%25%23%10%1
420
11th to 20thDay
18%14%32%23%11%2
412
21st to endDay
20%16%29%21%12%2
420
May1st to 10thDay
17%13%30%24%10%4
423
11th to 20thDay
14%10%24%26%17%9%
447
21st to endDay
14%5%19%28%19%15%
485
June1st to 10thDay
12%5%19%25%26%14%
450
11th to 20thDay
6%416%30%27%17%
450
21st to endDay
9%218%32%24%15%
542
July1st to 10thDay
11%311%26%27%21%
499
11th to 20thDay
11%310%25%28%23%
444
21st to endDay
10%410%26%28%22%
488
August1st to 10thDay
11%411%25%30%20%
446
11th to 20thDay
11%311%31%33%11%
439
21st to endDay
13%28%24%33%20%
495
September1st to 10thDay
13%211%23%35%16%
450
11th to 20thDay
15%5%10%22%31%16%
450
21st to endDay
14%5%18%26%28%10%
450
October1st to 10thDay
12%5%20%29%24%10%
450
11th to 20thDay
14%10%31%26%15%4
450
21st to endDay
22%12%25%27%11%4
345
November1st to 10thDay
18%9%29%30%10%4
270
11th to 20thDay
15%14%38%28%5%
270
21st to endDay
19%18%32%20%9%2
270
December1st to 10thDay
28%21%29%17%41
270
11th to 20thDay
27%17%28%18%10%
270
21st to endDay
29%20%32%14%41
297
January1st to 10thNight
25%18%31%21%5%
760
11th to 20thNight
28%20%29%19%4
760
21st to endNight
22%17%38%20%3
836
February1st to 10thNight
25%16%32%23%4
760
11th to 20thNight
28%17%35%18%2
742
21st to endNight
32%16%33%18%1
592
March1st to 10thNight
22%14%34%27%3
720
11th to 20thNight
24%15%32%21%7%1
720
21st to endNight
21%13%30%26%9%
779
April1st to 10thNight
15%11%33%30%11%
540
11th to 20thNight
17%9%32%30%11%
533
21st to endNight
17%7%30%32%13%1
540
May1st to 10thNight
14%7%29%31%18%1
540
11th to 20thNight
14%5%22%36%21%4
531
21st to endNight
9%215%35%32%6%
584
June1st to 10thNight
8%313%36%35%4
540
11th to 20thNight
5%213%34%38%9%
540
21st to endNight
6%113%37%36%7%
540
July1st to 10thNight
11%18%30%39%11%
525
11th to 20thNight
8%210%26%42%12%
522
21st to endNight
8%17%33%40%11%
591
August1st to 10thNight
8%27%28%47%9%
537
11th to 20thNight
8%19%34%42%6%
534
21st to endNight
10%17%30%43%9%
594
September1st to 10thNight
11%310%28%40%8%
600
11th to 20thNight
15%311%30%34%7%
720
21st to endNight
13%216%32%31%6%
720
October1st to 10thNight
12%5%17%31%28%7%
720
11th to 20thNight
18%8%22%32%17%2
720
21st to endNight
19%9%26%29%15%2
792
November1st to 10thNight
15%9%23%34%18%1
740
11th to 20thNight
17%13%30%28%11%1
760
21st to endNight
21%13%26%29%11%1
760
December1st to 10thNight
27%15%26%25%6%
760
11th to 20thNight
25%11%29%28%7%
760
21st to endNight
26%17%28%24%5%
836
Page generated at 2024-02-17 05:28:39. Version ac07

Copyright 2024 Attilla Danko


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