Choke Canyon State Park - Calliham Unit
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Choke Canyon State Park - Calliham Unit clear sky chart from 2005-11-05 to 2017-09-22.

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
52%
15321
25%
47036
18%
15278
59%
15278
35%
26668

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
41%
895
23%
2327
11%
895
48%
895
31%
1525
January16th to endNight
42%
831
26%
2367
14%
831
50%
831
32%
1444
February1st to 15thNight
38%
704
27%
2111
13%
699
49%
699
31%
1237
February16th to endNight
29%
632
27%
1894
9%
632
44%
632
34%
1074
March1st to 15thNight
31%
555
27%
1995
12%
555
48%
555
26%
1164
March16th to endNight
32%
576
23%
2112
14%
576
45%
576
29%
1168
April1st to 15thNight
27%
539
22%
1977
8%
539
46%
539
30%
1076
April16th to endNight
30%
540
24%
1821
13%
540
45%
540
26%
1100
May1st to 15thNight
30%
539
23%
1620
14%
539
43%
539
32%
975
May16th to endNight
47%
563
27%
1684
19%
561
61%
561
36%
977
June1st to 15thNight
69%
540
23%
1620
23%
540
74%
540
55%
770
June16th to endNight
65%
540
20%
1620
20%
540
70%
540
40%
903
July1st to 15thNight
72%
510
19%
1530
20%
510
75%
510
43%
830
July16th to endNight
80%
564
24%
1594
27%
531
83%
531
51%
798
August1st to 15thNight
86%
539
28%
1739
32%
536
88%
536
57%
766
August16th to endNight
76%
573
21%
1982
22%
573
79%
573
35%
1080
September1st to 15thNight
77%
540
20%
1980
23%
540
78%
540
31%
1104
September16th to endNight
69%
513
24%
1891
25%
513
71%
513
30%
1045
October1st to 15thNight
73%
495
34%
1815
33%
495
78%
495
44%
833
October16th to endNight
62%
688
36%
2096
26%
688
67%
688
47%
1052
November1st to 15thNight
55%
700
28%
2100
19%
700
59%
700
35%
1214
November16th to endNight
56%
885
31%
2325
17%
885
62%
885
45%
1321
December1st to 15thNight
45%
900
27%
2340
16%
900
49%
900
29%
1571
December16th to endNight
43%
960
23%
2496
12%
960
48%
960
30%
1641

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
10%4245%3445%7%45%
47842
Night
10%42332335%7%53%
47233
Cloud CoverDay
10%5%2443445%7%45%
47840
Night
10%42332335%7%53%
47233
TransparencyDay
37%5%10%19%17%8%
47540
Night
30%5%13%22%17%10%
47038
SeeingDay
10%418%33%26%7%
5261
Night
12%425%39%16%1
15327

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
19%5%14423345%43%
1611
16th to endDay
15%7%34423345%46%
1866
February1st to 15thDay
16%6%2432333449%
1750
16th to endDay
15%424323335%50%
1580
March1st to 15thDay
18%6%23424446%42%
1965
16th to endDay
12%5%2432335%6%49%
2112
April1st to 15thDay
10%5%244245%5%8%47%
1971
16th to endDay
12%6%35%423446%46%
2136
May1st to 15thDay
10%6%25%5%36%46%8%40%
2331
16th to endDay
8%425%6%35%5%8%10%39%
2430
June1st to 15thDay
22125%46%6%7%10%49%
2340
16th to endDay
6%425%7%5%7%7%7%9%35%
2340
July1st to 15thDay
7%426%6%47%5%6%8%39%
2340
16th to endDay
6%3245%36%6%6%9%44%
2466
August1st to 15thDay
1112435%5%5%9%58%
2208
16th to endDay
6%425%7%46%7%6%10%38%
2219
September1st to 15thDay
8%436%6%46%6%7%9%36%
1980
16th to endDay
9%425%6%45%46%8%41%
1881
October1st to 15thDay
6%415%435%447%52%
1815
16th to endDay
7%312223346%62%
1763
November1st to 15thDay
10%6%36%4335%46%45%
1758
16th to endDay
11%5%15%423345%51%
1632
December1st to 15thDay
24%7%36%323236%37%
1620
16th to endDay
16%7%35%33335%5%42%
1728
January1st to 15thNight
20%6%23322235%46%
2327
16th to endNight
17%42322335%6%48%
2367
February1st to 15thNight
14%423324347%50%
2102
16th to endNight
12%423313336%54%
1894
March1st to 15thNight
15%6%24312246%49%
1995
16th to endNight
10%424323447%52%
2112
April1st to 15thNight
9%325%32445%8%50%
1977
16th to endNight
12%5%2442445%8%44%
1821
May1st to 15thNight
7%424425%5%5%10%46%
1619
16th to endNight
6%4124345%6%11%48%
1683
June1st to 15thNight
211221246%10%64%
1620
16th to endNight
42233235%6%11%53%
1620
July1st to 15thNight
431342345%11%55%
1620
16th to endNight
411222335%9%61%
1702
August1st to 15thNight
21121245%8%69%
1749
16th to endNight
441434336%11%52%
1982
September1st to 15thNight
6%424435%46%9%49%
1980
16th to endNight
8%42442446%8%48%
1891
October1st to 15thNight
5%212323346%65%
1815
16th to endNight
6%412312235%65%
2096
November1st to 15thNight
9%41442445%6%52%
2100
16th to endNight
11%213313246%59%
2325
December1st to 15thNight
19%6%24323335%45%
2340
16th to endNight
17%6%23422346%46%
2496

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
19%5%24423345%44%
1611
16th to endDay
15%7%34423345%46%
1866
February1st to 15thDay
16%6%3242224449%
1750
16th to endDay
15%424313345%50%
1580
March1st to 15thDay
17%7%24323446%43%
1965
16th to endDay
12%5%2342335%7%49%
2110
April1st to 15thDay
10%5%15%3245%5%8%47%
1971
16th to endDay
13%6%24423446%47%
2136
May1st to 15thDay
11%6%245%35%5%6%8%41%
2331
16th to endDay
9%426%5%36%5%7%10%39%
2430
June1st to 15thDay
2213436%6%6%10%50%
2340
16th to endDay
6%425%6%5%7%6%8%8%36%
2340
July1st to 15thDay
7%425%6%47%6%6%8%39%
2340
16th to endDay
6%3236%36%7%6%9%45%
2466
August1st to 15thDay
1112435%45%9%58%
2208
16th to endDay
7%325%6%46%6%8%9%40%
2219
September1st to 15thDay
8%326%6%46%6%7%8%37%
1980
16th to endDay
10%5%15%5%35%5%6%8%41%
1881
October1st to 15thDay
7%4145%2445%6%53%
1815
16th to endDay
7%213222346%62%
1763
November1st to 15thDay
10%5%36%5%34446%45%
1758
16th to endDay
12%5%14423345%51%
1632
December1st to 15thDay
23%8%35%323236%37%
1620
16th to endDay
16%7%26%423247%42%
1728
January1st to 15thNight
20%6%23322345%47%
2327
16th to endNight
17%42321335%5%49%
2367
February1st to 15thNight
14%5%13323346%50%
2102
16th to endNight
13%424313245%55%
1894
March1st to 15thNight
14%6%24312236%50%
1995
16th to endNight
11%424323347%52%
2112
April1st to 15thNight
9%325%32436%9%50%
1977
16th to endNight
12%5%2433445%8%45%
1821
May1st to 15thNight
8%5%24235%46%9%47%
1619
16th to endNight
6%4134345%6%12%48%
1683
June1st to 15thNight
211221246%9%65%
1620
16th to endNight
432332346%11%53%
1620
July1st to 15thNight
421441345%10%55%
1620
16th to endNight
411222335%9%61%
1702
August1st to 15thNight
212212449%68%
1749
16th to endNight
441343346%10%52%
1982
September1st to 15thNight
6%42443446%10%49%
1980
16th to endNight
9%5%1442346%8%48%
1891
October1st to 15thNight
5%212223346%65%
1815
16th to endNight
6%412212235%65%
2096
November1st to 15thNight
9%42342445%6%52%
2100
16th to endNight
10%213322336%60%
2325
December1st to 15thNight
19%6%23314345%45%
2340
16th to endNight
18%5%23322346%47%
2496

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
43%36%15%17%13%
1612
16th to endDay
40%35%17%20%12%
1866
February1st to 15thDay
39%36%13%20%17%
1751
16th to endDay
37%45%18%22%12%
1580
March1st to 15thDay
43%37%14%18%12%
1965
16th to endDay
35%5%10%16%18%13%
2112
April1st to 15thDay
33%5%10%18%18%13%
1971
16th to endDay
39%47%18%17%12%
2136
May1st to 15thDay
41%6%11%16%14%9%
2331
16th to endDay
38%6%12%19%18%4
2434
June1st to 15thDay
26%8%13%23%21%5%
2340
16th to endDay
42%8%14%21%11%1
2340
July1st to 15thDay
40%6%14%22%14%1
2201
16th to endDay
31%8%19%33%6%
2311
August1st to 15thDay
22%6%18%36%14%
2194
16th to endDay
39%9%17%23%9%1
2219
September1st to 15thDay
42%9%14%17%13%2
1980
16th to endDay
40%6%11%17%15%7%
1881
October1st to 15thDay
31%6%8%18%24%10%
1815
16th to endDay
23%37%17%28%18%
1763
November1st to 15thDay
39%49%16%17%12%
1758
16th to endDay
35%46%14%19%19%
1632
December1st to 15thDay
50%35%14%15%10%
1620
16th to endDay
43%37%17%16%11%
1728
January1st to 15thNight
40%36%16%16%17%
2327
16th to endNight
36%38%17%19%14%
2367
February1st to 15thNight
34%49%14%17%20%
2112
16th to endNight
32%37%20%21%14%
1894
March1st to 15thNight
37%49%16%17%14%
1995
16th to endNight
32%5%12%18%18%12%
2112
April1st to 15thNight
31%5%11%19%18%13%
1977
16th to endNight
38%5%9%19%15%11%
1821
May1st to 15thNight
32%7%13%20%15%10%
1620
16th to endNight
29%7%15%28%16%3
1685
June1st to 15thNight
14%6%17%30%26%3
1620
16th to endNight
25%7%20%29%16%1
1620
July1st to 15thNight
22%8%24%33%10%
1530
16th to endNight
17%6%31%36%7%
1594
August1st to 15thNight
13%5%27%44%9%
1739
16th to endNight
26%8%25%30%7%1
1982
September1st to 15thNight
29%8%19%23%14%3
1980
16th to endNight
32%6%15%23%16%6%
1891
October1st to 15thNight
20%5%12%28%20%11%
1815
16th to endNight
22%36%19%28%19%
2096
November1st to 15thNight
32%413%17%20%11%
2100
16th to endNight
26%311%18%17%22%
2325
December1st to 15thNight
42%47%17%17%11%
2340
16th to endNight
39%47%15%19%13%
2496

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
16%327%42%8%1
90
16th to endDay
20%7%31%23%16%
96
February1st to 15thDay
6%10%30%33%15%4
90
16th to endDay
12%8%30%38%9%
81
March1st to 15thDay
31%5%28%20%14%
90
16th to endDay
11%8%33%37%8%1
96
April1st to 15thDay
10%13%27%34%14%
90
16th to endDay
12%10%41%25%9%
246
May1st to 15thDay
13%10%41%27%6%
468
16th to endDay
12%6%31%34%14%
517
June1st to 15thDay
311%49%29%5%
495
16th to endDay
8%11%36%32%11%
495
July1st to 15thDay
6%110%36%38%6%
475
16th to endDay
4433%46%9%
515
August1st to 15thDay
4436%35%19%
363
16th to endDay
10%8%35%27%17%
259
September1st to 15thDay
5%125%52%15%
135
16th to endDay
4412%45%33%
108
October1st to 15thDay
3424%42%25%
90
16th to endDay
16%27%36%31%6%
96
November1st to 15thDay
15%5%20%36%15%6%
90
16th to endDay
17%10%25%26%14%5%
90
December1st to 15thDay
40%113%21%16%7%
90
16th to endDay
23%15%27%21%10%1
96
January1st to 15thNight
21%5%24%35%11%
900
16th to endNight
18%6%27%39%7%
831
February1st to 15thNight
17%8%32%32%8%
704
16th to endNight
16%7%42%28%4
632
March1st to 15thNight
18%6%38%29%6%
555
16th to endNight
10%9%44%32%3
576
April1st to 15thNight
10%5%53%26%3
539
16th to endNight
11%9%46%26%5%
540
May1st to 15thNight
8%7%50%29%4
540
16th to endNight
7%236%44%9%
563
June1st to 15thNight
2121%58%16%
540
16th to endNight
4120%52%21%
540
July1st to 15thNight
412%57%24%1
510
16th to endNight
47%53%31%1
564
August1st to 15thNight
26%59%28%3
539
16th to endNight
6%7%46%36%3
573
September1st to 15thNight
6%5%41%40%5%
540
16th to endNight
12%7%33%41%5%
513
October1st to 15thNight
5%14%44%31%2
495
16th to endNight
7%321%43%21%2
688
November1st to 15thNight
10%323%39%21%1
700
16th to endNight
12%422%40%18%2
885
December1st to 15thNight
21%324%36%13%
900
16th to endNight
21%6%23%35%13%
960
Page generated at 2017-09-23 05:43:45. Version ac04

Copyright 2017 A. Danko


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