Oracle State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oracle State Park clear sky chart from 2005-11-06 to 2024-03-06.

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
67%
24112
35%
79420
28%
24019
76%
24019
46%
37953

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
61%
755
40%
3981
28%
736
73%
736
33%
1578
January11th to 20thNight
62%
753
47%
3869
31%
740
74%
740
43%
1230
January21st to endNight
56%
828
24%
4265
29%
814
70%
814
23%
2219
February1st to 10thNight
59%
760
36%
2452
29%
760
73%
760
44%
1197
February11th to 20thNight
52%
740
34%
2219
25%
740
65%
740
43%
1154
February21st to endNight
52%
628
36%
1780
26%
628
64%
628
43%
951
March1st to 10thNight
52%
742
37%
2040
23%
742
66%
742
45%
1085
March11th to 20thNight
60%
720
38%
1980
24%
720
72%
720
51%
1004
March21st to endNight
61%
792
38%
2178
23%
792
73%
792
51%
1110
April1st to 10thNight
60%
720
36%
1980
22%
720
72%
720
57%
940
April11th to 20thNight
56%
556
40%
1800
26%
556
73%
556
52%
770
April21st to endNight
61%
540
46%
1787
32%
540
79%
540
64%
690
May1st to 10thNight
63%
540
42%
1620
29%
540
77%
540
62%
688
May11th to 20thNight
67%
531
40%
1594
30%
531
75%
531
60%
704
May21st to endNight
67%
582
44%
1746
31%
582
77%
582
74%
678
June1st to 10thNight
75%
540
36%
1620
27%
540
79%
540
62%
717
June11th to 20thNight
78%
540
38%
1620
31%
540
82%
540
71%
660
June21st to endNight
76%
540
30%
1620
24%
540
79%
540
52%
786
July1st to 10thNight
79%
525
23%
1575
18%
525
80%
525
42%
862
July11th to 20thNight
78%
522
19%
1566
16%
522
78%
522
33%
946
July21st to endNight
76%
591
15%
1674
14%
558
76%
558
27%
1092
August1st to 10thNight
85%
537
22%
1602
21%
534
86%
534
44%
872
August11th to 20thNight
80%
534
28%
1606
27%
534
81%
534
37%
913
August21st to endNight
83%
598
30%
1984
32%
598
84%
598
39%
1042
September1st to 10thNight
76%
720
30%
1980
27%
720
78%
720
42%
1151
September11th to 20thNight
82%
720
41%
1980
34%
720
84%
720
60%
976
September21st to endNight
75%
720
38%
1980
26%
720
82%
720
57%
980
October1st to 10thNight
72%
720
38%
2070
27%
720
80%
720
56%
1003
October11th to 20thNight
76%
720
43%
2160
33%
720
84%
720
68%
901
October21st to endNight
76%
792
46%
2376
37%
792
83%
792
66%
997
November1st to 10thNight
73%
740
44%
2220
35%
740
81%
740
61%
980
November11th to 20thNight
73%
760
42%
2295
34%
760
82%
760
57%
1042
November21st to endNight
59%
760
36%
2470
30%
760
69%
760
41%
1229
December1st to 10thNight
61%
760
37%
2470
34%
760
69%
760
44%
1198
December11th to 20thNight
55%
759
32%
2934
28%
758
67%
758
30%
1619
December21st to endNight
55%
827
23%
4327
29%
817
65%
817
26%
1989

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
321342445%7%64%
79050
Night
321332445%7%65%
80540
TransparencyDay
22%4413%28%29%
78777
Night
21%3414%29%29%
80335
SeeingDay
6%13%28%32%17%4
13919
Night
46%18%37%29%5%
24148

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 10thDay
3324435%45%7%62%
2858
11th to 20thDay
22134345%5%5%67%
2860
21st to endDay
5%425%4345%7%8%54%
3146
February1st to 10thDay
431332445%6%65%
1724
11th to 20thDay
5%424423446%62%
1850
21st to endDay
441342435%7%63%
1673
March1st to 10thDay
32145%345%5%8%61%
2036
11th to 20thDay
3313334446%66%
1980
21st to endDay
2113324345%72%
2178
April1st to 10thDay
2112323446%73%
1980
11th to 20thDay
211221333478%
2108
21st to endDay
1112213245%78%
2168
May1st to 10thDay
111222334478%
2340
11th to 20thDay
1112213445%76%
2301
21st to endDay
111121222485%
2530
June1st to 10thDay
2112223247%75%
2340
11th to 20thDay
111111223384%
2340
21st to endDay
221233445%7%67%
2340
July1st to 10thDay
3223435%6%8%9%54%
2340
11th to 20thDay
4325%5%5%6%7%9%12%41%
2340
21st to endDay
7%435%7%47%9%10%12%33%
2545
August1st to 10thDay
6%425%5%36%7%6%9%48%
2328
11th to 20thDay
43246%46%7%8%11%47%
2292
21st to endDay
44245%36%5%7%10%51%
2368
September1st to 10thDay
6%3245%45%5%6%7%53%
1980
11th to 20thDay
311232345%5%69%
1980
21st to endDay
3212324346%70%
1980
October1st to 10thDay
221232335%6%71%
1890
11th to 20thDay
211121133480%
1800
21st to endDay
1112213346%76%
1980
November1st to 10thDay
11121235%7%76%
1859
11th to 20thDay
121322445%5%72%
1881
21st to endDay
332333445%7%64%
1710
December1st to 10thDay
5%31343446%7%61%
1710
11th to 20thDay
45%35%6%445%7%8%51%
2169
21st to endDay
33144346%6%6%58%
3146
January1st to 10thNight
33133245%6%7%63%
4097
11th to 20thNight
2212222346%75%
4110
21st to endNight
8%6%245%2445%8%51%
4521
February1st to 10thNight
431342345%6%66%
2452
11th to 20thNight
4324425%45%6%62%
2218
21st to endNight
33233245%5%5%63%
1780
March1st to 10thNight
22134345%6%7%63%
2040
11th to 20thNight
4222314346%70%
1980
21st to endNight
321232445%7%68%
2178
April1st to 10thNight
121222345%6%73%
1980
11th to 20thNight
121232334476%
1800
21st to endNight
121212235%82%
1787
May1st to 10thNight
1111222247%77%
1620
11th to 20thNight
1112213335%77%
1594
21st to endNight
21111112387%
1746
June1st to 10thNight
2112223436%75%
1620
11th to 20thNight
111111223484%
1620
21st to endNight
321332345%5%68%
1620
July1st to 10thNight
34235%36%5%6%9%54%
1620
11th to 20thNight
34246%5%7%7%10%14%39%
1620
21st to endNight
4435%6%5%8%8%11%13%33%
1773
August1st to 10thNight
3313435%6%7%11%53%
1611
11th to 20thNight
32246%46%6%8%10%49%
1606
21st to endNight
3224435%6%7%13%52%
1984
September1st to 10thNight
4425%5%345%6%8%55%
1980
11th to 20thNight
2214323345%73%
1980
21st to endNight
2212323446%71%
1980
October1st to 10thNight
2212423445%71%
2070
11th to 20thNight
2112212245%80%
2160
21st to endNight
111221223481%
2376
November1st to 10thNight
1112313346%75%
2220
11th to 20thNight
2212323346%73%
2295
21st to endNight
5%213424446%64%
2470
December1st to 10thNight
5%31333345%7%63%
2470
11th to 20thNight
4426%6%45%5%5%6%54%
3041
21st to endNight
43245%35%6%6%5%57%
4521

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
26%2210%41%19%
2859
11th to 20thDay
23%2119%37%18%
2860
21st to endDay
30%2421%29%14%
3146
February1st to 10thDay
24%3312%25%34%
1724
11th to 20thDay
27%4113%26%28%
1860
21st to endDay
24%3212%30%29%
1673
March1st to 10thDay
24%419%34%28%
2036
11th to 20thDay
22%319%32%32%
1980
21st to endDay
18%3211%40%27%
2178
April1st to 10thDay
15%317%40%34%
1980
11th to 20thDay
13%27%31%47%
2111
21st to endDay
12%319%35%40%
2168
May1st to 10thDay
13%218%29%46%
2340
11th to 20thDay
13%3310%28%43%
2304
21st to endDay
8%16%32%52%
2530
June1st to 10thDay
14%26%30%48%
2340
11th to 20thDay
9%2320%66%
2340
21st to endDay
19%339%23%43%
2340
July1st to 10thDay
26%6%10%17%16%25%
2276
11th to 20thDay
35%9%16%23%12%6%
2271
21st to endDay
41%8%20%19%9%3
2404
August1st to 10thDay
33%6%12%18%19%13%
2313
11th to 20thDay
32%7%12%19%21%9%
2292
21st to endDay
30%6%11%20%23%11%
2368
September1st to 10thDay
31%46%21%19%19%
1980
11th to 20thDay
19%4314%30%29%
1980
21st to endDay
19%4310%34%29%
1980
October1st to 10thDay
17%3417%27%33%
1890
11th to 20thDay
11%329%32%43%
1800
21st to endDay
13%3211%30%41%
1980
November1st to 10thDay
11%2213%41%30%
1859
11th to 20thDay
18%3212%32%33%
1881
21st to endDay
24%3113%27%32%
1710
December1st to 10thDay
24%4316%29%24%
1710
11th to 20thDay
33%2417%26%18%
2168
21st to endDay
28%3216%35%17%
3146
January1st to 10thNight
23%3210%43%19%
4097
11th to 20thNight
15%1222%42%18%
4110
21st to endNight
35%2421%26%12%
4521
February1st to 10thNight
23%3313%23%35%
2452
11th to 20thNight
25%3314%29%26%
2219
21st to endNight
25%3212%30%29%
1780
March1st to 10thNight
22%4211%31%30%
2040
11th to 20thNight
20%3112%31%34%
1980
21st to endNight
19%3215%37%24%
2178
April1st to 10thNight
15%3210%40%30%
1980
11th to 20thNight
15%319%31%42%
1800
21st to endNight
10%2110%36%42%
1787
May1st to 10thNight
11%2210%30%44%
1620
11th to 20thNight
13%3212%27%43%
1595
21st to endNight
8%16%31%54%
1746
June1st to 10thNight
14%26%26%51%
1620
11th to 20thNight
9%21317%69%
1620
21st to endNight
20%336%20%47%
1620
July1st to 10thNight
27%411%15%14%28%
1575
11th to 20thNight
33%7%16%25%13%6%
1566
21st to endNight
39%8%22%18%9%3
1674
August1st to 10thNight
25%6%15%21%16%17%
1602
11th to 20thNight
30%6%16%17%20%12%
1606
21st to endNight
27%5%13%21%23%11%
1984
September1st to 10thNight
28%6%8%20%19%20%
1980
11th to 20thNight
17%3416%31%30%
1980
21st to endNight
17%4313%33%30%
1980
October1st to 10thNight
18%2415%26%35%
2070
11th to 20thNight
11%2212%29%44%
2160
21st to endNight
10%2212%31%43%
2376
November1st to 10thNight
14%2114%36%33%
2220
11th to 20thNight
16%3215%29%35%
2295
21st to endNight
24%4313%29%28%
2470
December1st to 10thNight
23%3318%27%25%
2470
11th to 20thNight
34%2415%27%18%
3041
21st to endNight
30%2311%32%22%
4521

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
11%15%32%34%8%
270
11th to 20thDay
9%10%32%34%12%2
270
21st to endDay
6%16%30%35%12%1
297
February1st to 10thDay
7%18%28%32%13%3
284
11th to 20thDay
14%23%35%24%4
455
21st to endDay
14%29%33%19%41
382
March1st to 10thDay
10%27%36%19%7%
441
11th to 20thDay
13%21%30%24%10%2
420
21st to endDay
10%30%34%18%7%2
462
April1st to 10thDay
7%22%35%24%10%3
420
11th to 20thDay
6%26%38%21%7%3
412
21st to endDay
7%21%36%24%9%4
420
May1st to 10thDay
6%17%41%21%11%4
423
11th to 20thDay
314%36%31%14%3
448
21st to endDay
414%39%32%10%1
485
June1st to 10thDay
48%38%30%17%3
450
11th to 20thDay
29%38%31%17%2
450
21st to endDay
5%5%29%40%18%2
450
July1st to 10thDay
3116%44%31%4
446
11th to 20thDay
6%19%45%30%9%
444
21st to endDay
8%19%36%34%11%
487
August1st to 10thDay
5%210%38%30%13%
447
11th to 20thDay
6%26%43%34%9%
437
21st to endDay
339%41%32%13%
495
September1st to 10thDay
7%418%41%23%6%
450
11th to 20thDay
3322%43%22%6%
450
21st to endDay
49%28%34%18%7%
450
October1st to 10thDay
410%29%30%21%5%
360
11th to 20thDay
46%29%34%22%4
270
21st to endDay
39%29%30%24%4
297
November1st to 10thDay
413%31%33%18%2
270
11th to 20thDay
48%32%35%19%2
270
21st to endDay
6%17%32%32%12%1
270
December1st to 10thDay
8%10%30%37%14%1
270
11th to 20thDay
6%13%39%30%10%1
270
21st to endDay
7%21%33%31%7%1
297
January1st to 10thNight
5%424%42%21%3
760
11th to 20thNight
7%6%20%40%23%4
760
21st to endNight
9%8%22%40%19%3
836
February1st to 10thNight
5%7%24%34%24%5%
760
11th to 20thNight
6%9%27%39%17%1
744
21st to endNight
6%12%27%39%14%2
628
March1st to 10thNight
412%28%39%14%2
742
11th to 20thNight
6%8%23%33%24%6%
720
21st to endNight
5%8%23%38%23%3
792
April1st to 10thNight
39%24%42%21%2
720
11th to 20thNight
312%27%36%21%1
556
21st to endNight
29%27%37%21%4
540
May1st to 10thNight
38%25%39%23%2
540
11th to 20thNight
16%23%42%23%5%
531
21st to endNight
25%24%42%24%3
584
June1st to 10thNight
2316%45%31%2
540
11th to 20thNight
2215%48%30%3
540
21st to endNight
2312%38%39%5%
540
July1st to 10thNight
5%17%35%46%6%
525
11th to 20thNight
41430%52%9%
522
21st to endNight
6%2325%51%14%
591
August1st to 10thNight
32221%57%15%
537
11th to 20thNight
32422%57%12%
534
21st to endNight
41324%54%15%
598
September1st to 10thNight
6%27%30%43%13%
720
11th to 20thNight
319%37%41%9%
720
21st to endNight
3215%36%35%9%
720
October1st to 10thNight
2416%41%32%4
720
11th to 20thNight
3315%42%32%6%
720
21st to endNight
25%14%40%30%9%
792
November1st to 10thNight
15%17%41%29%6%
740
11th to 20thNight
25%17%44%29%4
760
21st to endNight
5%10%21%38%21%5%
760
December1st to 10thNight
7%5%21%39%24%3
760
11th to 20thNight
7%7%25%37%20%4
760
21st to endNight
6%9%23%38%20%4
836
Page generated at 2024-03-03 04:28:55. Version ac07

Copyright © 2024 Attilla Danko.


Oracle State Park Clear Sky Chart |Charts Home