Oak Canyon Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oak Canyon Park clear sky chart from 2005-11-05 to 2017-09-23.

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
76%
15842
35%
46905
30%
15794
80%
15794
52%
22789

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
60%
720
29%
2440
26%
716
69%
716
40%
1198
January16th to endNight
55%
768
35%
2413
27%
768
69%
768
39%
1260
February1st to 15thNight
67%
697
36%
2102
31%
697
76%
697
47%
1070
February16th to endNight
62%
632
29%
1895
31%
632
66%
632
36%
1078
March1st to 15thNight
67%
720
29%
2160
28%
720
74%
720
47%
1086
March16th to endNight
73%
768
31%
1989
24%
768
77%
768
49%
1093
April1st to 15thNight
68%
719
31%
1799
20%
719
72%
719
50%
1003
April16th to endNight
76%
720
33%
1800
18%
720
80%
720
60%
923
May1st to 15thNight
77%
653
29%
1733
21%
653
78%
653
52%
929
May16th to endNight
81%
561
31%
1685
25%
561
83%
561
58%
791
June1st to 15thNight
89%
405
32%
1485
35%
405
90%
405
51%
632
June16th to endNight
94%
360
40%
1440
49%
360
94%
360
65%
489
July1st to 15thNight
92%
340
36%
1360
43%
340
92%
340
59%
498
July16th to endNight
90%
618
35%
1640
28%
578
90%
578
61%
765
August1st to 15thNight
90%
717
36%
1790
24%
713
90%
713
68%
869
August16th to endNight
92%
764
45%
1910
30%
764
92%
764
75%
888
September1st to 15thNight
89%
720
41%
1806
32%
720
89%
720
68%
883
September16th to endNight
92%
688
44%
1903
43%
688
93%
688
73%
821
October1st to 15thNight
82%
660
37%
1864
37%
660
84%
660
56%
909
October16th to endNight
78%
704
41%
2112
43%
704
81%
704
56%
986
November1st to 15thNight
77%
700
37%
2271
37%
700
84%
700
57%
997
November16th to endNight
71%
720
38%
2340
37%
720
78%
720
51%
1075
December1st to 15thNight
65%
720
36%
2340
31%
720
74%
720
40%
1186
December16th to endNight
57%
768
32%
2628
27%
768
68%
768
35%
1360

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
4212212346%67%
47980
Night
4212212346%67%
47107
TransparencyDay
19%26%18%28%24%
47672
Night
19%25%18%26%26%
46916
SeeingDay
5%6%22%35%23%7%
5992
Night
5%28%32%39%10%
15852

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
6%314422335%61%
1495
16th to endDay
12%422222335%58%
1808
February1st to 15thDay
7%322312345%60%
1751
16th to endDay
10%424423336%54%
1579
March1st to 15thDay
43242235%46%60%
1800
16th to endDay
431242445%9%56%
2232
April1st to 15thDay
6%323322447%59%
2149
16th to endDay
4212211336%69%
2160
May1st to 15thDay
4322212447%63%
2217
16th to endDay
2312212338%67%
2429
June1st to 15thDay
341421325%8%61%
2470
16th to endDay
111111235%78%
2520
July1st to 15thDay
1212213246%71%
2520
16th to endDay
2112212346%72%
2408
August1st to 15thDay
111212135%77%
2160
16th to endDay
1112235%79%
2292
September1st to 15thDay
111112235%78%
2154
16th to endDay
11121222478%
1893
October1st to 15thDay
422213345%68%
1763
16th to endDay
221331234469%
1760
November1st to 15thDay
3213213335%68%
1587
16th to endDay
3313423336%64%
1620
December1st to 15thDay
6%41332345%9%55%
1620
16th to endDay
10%414423346%55%
1593
January1st to 15thNight
6%413323346%59%
2440
16th to endNight
10%423312235%60%
2413
February1st to 15thNight
6%32322235%5%62%
2101
16th to endNight
13%413423345%53%
1895
March1st to 15thNight
442321345%6%62%
2160
16th to endNight
431242435%6%60%
1989
April1st to 15thNight
6%423212236%64%
1799
16th to endNight
3111212348%68%
1800
May1st to 15thNight
4312313347%64%
1733
16th to endNight
1213212337%70%
1684
June1st to 15thNight
1212223449%66%
1485
16th to endNight
11111325%79%
1440
July1st to 15thNight
112321246%73%
1440
16th to endNight
211221335%7%68%
1754
August1st to 15thNight
211112237%73%
1800
16th to endNight
1121236%77%
1910
September1st to 15thNight
222112225%76%
1806
16th to endNight
1211113480%
1903
October1st to 15thNight
311232233470%
1864
16th to endNight
4312112235%71%
2112
November1st to 15thNight
321221223473%
2271
16th to endNight
4212313346%66%
2340
December1st to 15thNight
7%223323346%59%
2340
16th to endNight
11%412213236%59%
2628

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
25%26%13%24%26%
1495
16th to endDay
28%25%17%18%26%
1808
February1st to 15thDay
25%2415%27%24%
1751
16th to endDay
31%26%19%28%10%
1579
March1st to 15thDay
23%38%20%22%20%
1800
16th to endDay
24%411%25%19%15%
2232
April1st to 15thDay
25%310%25%23%12%
2149
16th to endDay
17%210%24%28%17%
2160
May1st to 15thDay
21%39%21%26%18%
2217
16th to endDay
16%310%30%29%9%
2432
June1st to 15thDay
22%28%18%31%16%
2470
16th to endDay
10%1312%36%34%
2520
July1st to 15thDay
15%2313%31%34%
2371
16th to endDay
15%25%23%30%22%
2260
August1st to 15thDay
12%1115%39%29%
2146
16th to endDay
8%2114%41%31%
2292
September1st to 15thDay
10%2215%32%36%
2154
16th to endDay
12%1118%34%31%
1893
October1st to 15thDay
18%25%22%24%26%
1763
16th to endDay
17%3315%24%35%
1760
November1st to 15thDay
19%2415%24%34%
1587
16th to endDay
22%25%14%22%32%
1620
December1st to 15thDay
25%38%16%22%23%
1620
16th to endDay
29%46%18%21%19%
1593
January1st to 15thNight
25%25%14%23%27%
2440
16th to endNight
27%25%14%16%32%
2413
February1st to 15thNight
23%25%16%25%26%
2112
16th to endNight
32%35%17%25%15%
1895
March1st to 15thNight
21%38%20%25%20%
2160
16th to endNight
23%39%24%23%16%
1989
April1st to 15thNight
23%27%27%24%13%
1799
16th to endNight
16%29%26%25%19%
1800
May1st to 15thNight
20%39%21%27%16%
1734
16th to endNight
16%29%29%28%12%
1685
June1st to 15thNight
15%410%21%31%16%
1485
16th to endNight
10%1215%34%35%
1440
July1st to 15thNight
12%2215%26%41%
1360
16th to endNight
15%25%24%28%24%
1640
August1st to 15thNight
12%2112%37%32%
1790
16th to endNight
9%212%41%33%
1910
September1st to 15thNight
13%1312%31%37%
1806
16th to endNight
10%1216%33%35%
1903
October1st to 15thNight
17%3319%27%29%
1864
16th to endNight
16%3314%22%38%
2112
November1st to 15thNight
16%2415%24%36%
2271
16th to endNight
18%35%17%21%34%
2340
December1st to 15thNight
26%26%15%21%26%
2340
16th to endNight
27%36%16%23%21%
2628

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
15%10%42%26%4
123
16th to endDay
15%15%32%25%10%1
269
February1st to 15thDay
9%8%35%31%10%3
266
16th to endDay
13%12%31%30%10%1
238
March1st to 15thDay
5%15%31%27%16%2
270
16th to endDay
6%8%34%36%9%4
288
April1st to 15thDay
7%11%35%28%9%6%
269
16th to endDay
114%38%32%9%3
270
May1st to 15thDay
7%8%28%32%18%3
288
16th to endDay
37%25%37%20%5%
330
June1st to 15thDay
6%321%36%23%7%
315
16th to endDay
7%36%39%15%
315
July1st to 15thDay
5%36%42%15%
305
16th to endDay
25%29%42%19%
327
August1st to 15thDay
35%45%34%10%
315
16th to endDay
6%37%41%14%
332
September1st to 15thDay
214%46%26%8%
315
16th to endDay
1218%43%25%8%
284
October1st to 15thDay
27%30%38%18%3
255
16th to endDay
46%23%41%21%2
272
November1st to 15thDay
45%12%37%21%18%
93
16th to endDay
310%23%37%22%3
90
December1st to 15thDay
38%20%34%30%3
90
16th to endDay
8%13%31%30%12%4
73
January1st to 15thNight
9%417%40%21%6%
720
16th to endNight
12%5%16%37%23%4
768
February1st to 15thNight
7%312%41%28%5%
704
16th to endNight
14%311%41%23%6%
632
March1st to 15thNight
6%413%41%28%5%
720
16th to endNight
5%39%40%35%5%
768
April1st to 15thNight
7%49%42%30%4
719
16th to endNight
3410%36%37%8%
720
May1st to 15thNight
6%26%35%41%7%
654
16th to endNight
117%37%43%8%
563
June1st to 15thNight
1232%52%9%
405
16th to endNight
20%68%10%
360
July1st to 15thNight
27%69%20%
340
16th to endNight
216%63%25%
618
August1st to 15thNight
212%64%19%
717
16th to endNight
110%59%28%
764
September1st to 15thNight
3118%53%22%
720
16th to endNight
1126%53%17%
688
October1st to 15thNight
415%37%41%8%
660
16th to endNight
5%28%35%35%13%
704
November1st to 15thNight
4110%42%30%10%
700
16th to endNight
6%212%35%33%9%
720
December1st to 15thNight
8%412%41%26%7%
720
16th to endNight
14%6%14%36%24%3
768
Page generated at 2017-09-24 06:15:50. Version ac04

Copyright 2017 A. Danko


Oak Canyon Park Clear Sky Chart | Charts Home