Clayton Lake State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Clayton Lake State Park clear sky chart from 2005-11-05 to 2017-10-31.

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
47%
15951
30%
47350
17%
15905
60%
15905
43%
24964

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
43%
900
29%
2506
15%
895
55%
895
48%
1303
January16th to endNight
42%
798
37%
2500
21%
798
60%
798
50%
1186
February1st to 15thNight
35%
704
29%
2112
14%
700
50%
700
40%
1144
February16th to endNight
30%
632
37%
1894
12%
632
54%
632
44%
956
March1st to 15thNight
40%
720
29%
2160
14%
720
53%
720
43%
1124
March16th to endNight
32%
624
32%
2004
13%
624
53%
624
42%
994
April1st to 15thNight
31%
539
29%
1798
11%
539
53%
539
38%
910
April16th to endNight
33%
540
27%
1800
14%
540
55%
540
38%
920
May1st to 15thNight
39%
540
28%
1653
15%
540
57%
540
38%
885
May16th to endNight
41%
562
24%
1650
12%
561
54%
561
39%
924
June1st to 15thNight
46%
540
23%
1440
11%
540
56%
540
47%
789
June16th to endNight
58%
540
22%
1440
14%
540
65%
540
46%
801
July1st to 15thNight
70%
510
22%
1360
17%
510
73%
510
43%
790
July16th to endNight
69%
564
20%
1479
18%
531
70%
531
38%
884
August1st to 15thNight
68%
539
14%
1789
16%
536
69%
536
26%
1112
August16th to endNight
68%
573
22%
1910
25%
573
71%
573
33%
1090
September1st to 15thNight
64%
540
24%
1815
22%
540
70%
540
34%
1011
September16th to endNight
54%
537
35%
1980
29%
537
66%
537
41%
942
October1st to 15thNight
46%
591
33%
2031
20%
591
61%
591
41%
1000
October16th to endNight
55%
823
40%
2359
20%
823
67%
823
58%
1099
November1st to 15thNight
54%
875
37%
2275
17%
875
65%
875
61%
1121
November16th to endNight
50%
900
39%
2340
18%
900
62%
900
55%
1195
December1st to 15thNight
43%
900
31%
2367
14%
900
55%
900
47%
1301
December16th to endNight
41%
960
33%
2688
17%
960
53%
960
41%
1483

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
431332445%7%58%
48405
Night
431332445%7%59%
47529
Cloud CoverDay
431332445%7%58%
48403
Night
431332345%7%60%
47529
TransparencyDay
23%5%11%22%24%13%
48087
Night
23%5%10%22%24%13%
47350
SeeingDay
7%7%28%33%17%4
5862
Night
6%6%35%37%13%1
15952

By Month

Percentage Cloud Cover SW (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
3315%222235%66%
1432
16th to endDay
2323213335%67%
1731
February1st to 15thDay
3425%424336%59%
1750
16th to endDay
241431335%7%61%
1580
March1st to 15thDay
242332445%6%60%
1800
16th to endDay
441332435%6%58%
2217
April1st to 15thDay
4423314446%60%
2150
16th to endDay
6%41332345%7%57%
2160
May1st to 15thDay
7%41242345%7%56%
2297
16th to endDay
331332345%8%59%
2462
June1st to 15thDay
3112325%5%8%9%56%
2520
16th to endDay
22132146%6%8%59%
2520
July1st to 15thDay
5%313425%5%7%10%49%
2520
16th to endDay
4213437%7%8%10%48%
2584
August1st to 15thDay
5%3246%35%7%8%12%41%
2160
16th to endDay
5%324426%6%6%9%48%
2292
September1st to 15thDay
8%324425%36%8%49%
2145
16th to endDay
5%312223347%64%
1980
October1st to 15thDay
5%312223346%65%
1926
16th to endDay
221221223474%
1850
November1st to 15thDay
1212213446%70%
1583
16th to endDay
331221233470%
1620
December1st to 15thDay
2424422347%60%
1590
16th to endDay
5%6%24312335%59%
1536
January1st to 15thNight
3314313335%64%
2506
16th to endNight
3313223347%65%
2500
February1st to 15thNight
35%14324347%57%
2102
16th to endNight
441321335%7%61%
1894
March1st to 15thNight
4323413446%60%
2160
16th to endNight
5%312223446%63%
2004
April1st to 15thNight
5%42232345%7%58%
1798
16th to endNight
6%41331335%7%58%
1800
May1st to 15thNight
8%313224435%60%
1652
16th to endNight
5%31332445%7%57%
1648
June1st to 15thNight
21133235%6%9%59%
1440
16th to endNight
3213315%46%10%55%
1440
July1st to 15thNight
2313426%6%6%13%50%
1440
16th to endNight
6%2135%36%48%13%44%
1580
August1st to 15thNight
6%4245%5%6%7%8%12%37%
1800
16th to endNight
6%414326%5%6%9%48%
1910
September1st to 15thNight
7%4133245%6%10%49%
1815
16th to endNight
5%213322246%63%
1980
October1st to 15thNight
7%312213325%64%
2031
16th to endNight
312213235%71%
2359
November1st to 15thNight
121221235%5%72%
2275
16th to endNight
3312212245%68%
2340
December1st to 15thNight
25%23423347%61%
2367
16th to endNight
45%24323346%59%
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
2414313335%66%
1432
16th to endDay
2323213336%66%
1731
February1st to 15thDay
3425%423336%59%
1750
16th to endDay
231431335%7%62%
1580
March1st to 15thDay
24143235%47%60%
1800
16th to endDay
5%5%1332435%6%58%
2215
April1st to 15thDay
5%324224446%60%
2150
16th to endDay
6%42332345%7%56%
2160
May1st to 15thDay
8%31241345%7%56%
2297
16th to endDay
431331445%8%60%
2462
June1st to 15thDay
21123246%6%10%56%
2520
16th to endDay
32123246%6%8%59%
2520
July1st to 15thDay
5%313425%6%7%9%49%
2520
16th to endDay
4212435%7%9%9%48%
2584
August1st to 15thDay
6%315%6%35%6%8%12%42%
2160
16th to endDay
5%314435%6%7%8%48%
2292
September1st to 15thDay
9%325%42445%8%49%
2145
16th to endDay
5%312213346%65%
1980
October1st to 15thDay
5%312222336%65%
1926
16th to endDay
222212235%73%
1850
November1st to 15thDay
1113213346%69%
1583
16th to endDay
331311223470%
1620
December1st to 15thDay
2423313447%60%
1590
16th to endDay
5%6%2423336%58%
1536
January1st to 15thNight
3314322345%65%
2506
16th to endNight
3323213346%65%
2500
February1st to 15thNight
45%14414347%57%
2102
16th to endNight
442231335%5%62%
1894
March1st to 15thNight
4423323346%61%
2160
16th to endNight
4413213446%63%
2004
April1st to 15thNight
6%412323448%57%
1798
16th to endNight
7%31232435%7%58%
1800
May1st to 15thNight
7%313214336%60%
1652
16th to endNight
6%31332446%7%57%
1648
June1st to 15thNight
31133135%6%9%59%
1440
16th to endNight
3222216%46%10%56%
1440
July1st to 15thNight
23124246%7%12%50%
1440
16th to endNight
6%245%45%48%12%45%
1580
August1st to 15thNight
7%3146%36%7%7%11%38%
1800
16th to endNight
7%21433447%8%49%
1910
September1st to 15thNight
8%3133235%5%10%50%
1815
16th to endNight
5%313323345%64%
1980
October1st to 15thNight
7%313222235%64%
2031
16th to endNight
311212335%72%
2359
November1st to 15thNight
1112212345%72%
2275
16th to endNight
3312213245%69%
2340
December1st to 15thNight
25%24422347%61%
2367
16th to endNight
45%23423335%60%
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
21%47%26%33%8%
1433
16th to endDay
19%37%25%31%12%
1731
February1st to 15thDay
25%410%23%24%10%
1751
16th to endDay
21%37%26%24%17%
1580
March1st to 15thDay
22%47%22%27%14%
1800
16th to endDay
24%48%21%28%12%
2217
April1st to 15thDay
24%49%22%25%14%
2150
16th to endDay
25%410%22%24%12%
2160
May1st to 15thDay
26%5%11%21%23%12%
2297
16th to endDay
20%6%12%20%22%16%
2466
June1st to 15thDay
19%8%15%19%21%17%
2520
16th to endDay
18%5%12%23%20%19%
2520
July1st to 15thDay
25%8%14%21%18%10%
2371
16th to endDay
24%10%17%23%20%3
2422
August1st to 15thDay
30%11%18%20%13%6%
2147
16th to endDay
28%8%13%22%20%6%
2292
September1st to 15thDay
30%6%13%24%16%8%
2145
16th to endDay
20%410%21%29%14%
1980
October1st to 15thDay
21%5%8%16%30%17%
1926
16th to endDay
14%27%20%35%19%
1850
November1st to 15thDay
14%38%21%31%19%
1583
16th to endDay
18%26%18%31%22%
1620
December1st to 15thDay
23%410%28%23%10%
1590
16th to endDay
28%29%23%26%9%
1536
January1st to 15thNight
22%29%26%30%9%
2506
16th to endNight
19%27%24%31%13%
2500
February1st to 15thNight
26%49%23%26%9%
2112
16th to endNight
22%36%24%27%15%
1894
March1st to 15thNight
24%38%22%29%11%
2160
16th to endNight
22%311%21%24%17%
2004
April1st to 15thNight
24%49%24%22%13%
1798
16th to endNight
24%5%13%23%19%14%
1800
May1st to 15thNight
25%6%9%23%22%13%
1653
16th to endNight
25%7%14%17%17%17%
1650
June1st to 15thNight
20%7%16%23%15%17%
1440
16th to endNight
22%7%14%22%15%17%
1440
July1st to 15thNight
24%8%17%23%17%9%
1360
16th to endNight
26%10%21%21%16%2
1479
August1st to 15thNight
33%12%19%18%11%5%
1789
16th to endNight
28%9%14%25%16%5%
1910
September1st to 15thNight
28%7%18%24%14%6%
1815
16th to endNight
22%48%21%28%13%
1980
October1st to 15thNight
24%38%17%28%16%
2031
16th to endNight
15%37%20%33%20%
2359
November1st to 15thNight
13%38%21%31%20%
2275
16th to endNight
18%25%21%30%22%
2340
December1st to 15thNight
23%39%26%28%7%
2367
16th to endNight
26%48%24%27%9%
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
11%5%31%30%20%2
90
16th to endDay
214%35%26%18%3
96
February1st to 15thDay
7%7%42%24%15%2
90
16th to endDay
412%46%28%6%1
81
March1st to 15thDay
2446%33%12%1
90
16th to endDay
11%21%37%19%8%
251
April1st to 15thDay
9%23%37%21%42
269
16th to endDay
13%22%41%17%5%
270
May1st to 15thDay
9%13%37%25%11%2
434
16th to endDay
7%9%37%31%12%1
517
June1st to 15thDay
4433%32%19%5%
495
16th to endDay
3325%36%24%5%
495
July1st to 15thDay
7%116%41%26%6%
475
16th to endDay
6%10%40%32%9%
482
August1st to 15thDay
8%217%41%23%6%
315
16th to endDay
6%120%45%22%4
332
September1st to 15thDay
6%322%41%19%8%
300
16th to endDay
16%322%25%23%7%
135
October1st to 15thDay
10%5%22%31%23%5%
135
16th to endDay
5%429%40%11%7%
144
November1st to 15thDay
38%25%35%22%4
90
16th to endDay
15%14%35%26%7%
90
December1st to 15thDay
5%13%41%33%6%
90
16th to endDay
16%10%36%30%6%
96
January1st to 15thNight
6%7%38%35%11%1
900
16th to endNight
46%44%34%9%1
798
February1st to 15thNight
6%7%46%31%8%
704
16th to endNight
8%9%49%27%41
632
March1st to 15thNight
7%9%40%34%7%
720
16th to endNight
6%10%48%27%7%
624
April1st to 15thNight
9%11%48%26%4
539
16th to endNight
8%8%47%29%5%
540
May1st to 15thNight
8%8%40%34%8%
540
16th to endNight
6%6%43%32%10%
563
June1st to 15thNight
3440%40%10%
540
16th to endNight
3230%48%15%
540
July1st to 15thNight
416%51%25%1
510
16th to endNight
6%14%48%28%2
564
August1st to 15thNight
7%111%46%31%1
539
16th to endNight
7%115%43%29%2
573
September1st to 15thNight
9%219%47%20%1
540
16th to endNight
8%330%35%19%2
537
October1st to 15thNight
10%435%37%10%2
591
16th to endNight
45%33%36%16%4
823
November1st to 15thNight
35%33%42%12%2
875
16th to endNight
5%8%33%37%12%1
900
December1st to 15thNight
5%8%40%34%10%1
900
16th to endNight
6%10%37%35%8%
960
Page generated at 2017-11-01 15:23:34. Version ac04

Copyright 2017 A. Danko


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