Ojai
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ojai clear sky chart from 2005-11-06 to 2024-01-17.

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
73%
24264
36%
74629
31%
24212
80%
24212
53%
35460

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
58%
756
30%
2610
26%
756
68%
756
37%
1323
January11th to 20thNight
63%
746
37%
2423
31%
746
74%
746
48%
1155
January21st to endNight
53%
792
38%
2523
28%
792
68%
792
42%
1271
February1st to 10thNight
62%
720
38%
2160
33%
720
72%
720
47%
1098
February11th to 20thNight
61%
700
38%
2098
32%
700
72%
700
51%
1024
February21st to endNight
56%
592
31%
1776
25%
592
67%
592
43%
931
March1st to 10thNight
58%
720
27%
2160
22%
720
68%
720
40%
1180
March11th to 20thNight
65%
720
28%
2034
24%
720
71%
720
46%
1088
March21st to endNight
64%
792
33%
2012
21%
792
72%
792
52%
1098
April1st to 10thNight
68%
720
33%
1800
21%
720
73%
720
53%
1000
April11th to 20thNight
65%
711
37%
1779
18%
711
73%
711
59%
925
April21st to endNight
70%
720
35%
1800
17%
720
76%
720
60%
932
May1st to 10thNight
72%
720
30%
1800
17%
720
75%
720
58%
951
May11th to 20thNight
77%
552
36%
1616
26%
552
80%
552
61%
737
May21st to endNight
75%
574
31%
1738
23%
574
79%
574
61%
769
June1st to 10thNight
86%
360
36%
1440
42%
360
89%
360
56%
543
June11th to 20thNight
89%
360
39%
1440
45%
360
92%
360
66%
480
June21st to endNight
94%
360
42%
1440
51%
360
95%
360
73%
454
July1st to 10thNight
94%
350
38%
1400
46%
350
94%
350
67%
460
July11th to 20thNight
95%
413
40%
1457
41%
413
95%
413
70%
519
July21st to endNight
92%
667
39%
1746
30%
630
93%
630
71%
766
August1st to 10thNight
92%
716
37%
1780
24%
712
92%
712
75%
832
August11th to 20thNight
94%
712
41%
1780
25%
712
94%
712
80%
801
August21st to endNight
95%
792
47%
1980
32%
792
95%
792
83%
879
September1st to 10thNight
91%
720
44%
1800
34%
720
91%
720
77%
835
September11th to 20thNight
90%
720
47%
1873
41%
720
91%
720
77%
822
September21st to endNight
87%
720
47%
1980
43%
720
91%
720
78%
837
October1st to 10thNight
83%
720
39%
2017
38%
720
87%
720
66%
912
October11th to 20thNight
79%
720
41%
2160
41%
720
84%
720
60%
976
October21st to endNight
76%
792
43%
2376
42%
792
82%
792
61%
1051
November1st to 10thNight
75%
740
39%
2370
37%
740
84%
740
59%
1015
November11th to 20thNight
75%
760
39%
2470
36%
760
84%
760
57%
1071
November21st to endNight
65%
760
37%
2470
36%
760
73%
760
50%
1155
December1st to 10thNight
63%
760
36%
2470
33%
760
71%
760
44%
1210
December11th to 20thNight
57%
760
29%
3108
29%
759
67%
759
27%
1850
December21st to endNight
57%
827
21%
4743
29%
817
68%
817
22%
2510

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
5%312323346%69%
74824
Night
5%312223345%70%
75008
TransparencyDay
18%36%18%28%26%
74544
Night
18%36%18%27%28%
74809
SeeingDay
6%8%26%38%17%5%
14448
Night
5%215%34%34%10%
24283

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
10%32432345%6%58%
1552
11th to 20thDay
8%313323227%65%
1675
21st to endDay
11%5%23312246%61%
1831
February1st to 10thDay
8%423323235%64%
1800
11th to 20thDay
7%31332425%8%63%
1750
21st to endDay
8%413423446%60%
1480
March1st to 10thDay
8%424445%5%5%6%53%
1800
11th to 20thDay
8%32332345%7%59%
1921
21st to endDay
6%22333445%7%61%
2343
April1st to 10thDay
6%31332435%9%61%
2160
11th to 20thDay
4324323347%66%
2129
21st to endDay
4312223347%69%
2160
May1st to 10thDay
6%423223347%65%
2160
11th to 20thDay
2412223246%70%
2278
21st to endDay
4412313346%69%
2534
June1st to 10thDay
3422323346%67%
2520
11th to 20thDay
2213222346%73%
2520
21st to endDay
21112223481%
2520
July1st to 10thDay
1111222235%79%
2520
11th to 20thDay
2112212335%79%
2449
21st to endDay
2111123446%75%
2467
August1st to 10thDay
1112223335%77%
2149
11th to 20thDay
11112223483%
2122
21st to endDay
11121323483%
2376
September1st to 10thDay
1111112245%80%
2160
11th to 20thDay
11121222483%
2085
21st to endDay
11222223382%
1980
October1st to 10thDay
321222234475%
1940
11th to 20thDay
311232223477%
1800
21st to endDay
231242323475%
1980
November1st to 10thDay
221231334475%
1706
11th to 20thDay
4312223346%70%
1710
21st to endDay
3213434447%65%
1710
December1st to 10thDay
7%42332345%7%61%
1710
11th to 20thDay
18%6%2332345%6%47%
2033
21st to endDay
12%5%245%2445%7%49%
2794
January1st to 10thNight
9%31333435%7%58%
2610
11th to 20thNight
6%223324347%65%
2423
21st to endNight
10%413323335%63%
2523
February1st to 10thNight
7%423322336%66%
2160
11th to 20thNight
7%313213335%68%
2098
21st to endNight
10%313423335%64%
1776
March1st to 10thNight
8%42333445%7%56%
2160
11th to 20thNight
6%31342435%8%60%
2034
21st to endNight
6%31232435%6%65%
2012
April1st to 10thNight
6%22332435%7%65%
1800
11th to 20thNight
422211335%6%72%
1779
21st to endNight
3212224336%73%
1800
May1st to 10thNight
3213324346%69%
1800
11th to 20thNight
2212113345%75%
1615
21st to endNight
2212223345%75%
1738
June1st to 10thNight
1313123346%74%
1440
11th to 20thNight
111121233480%
1440
21st to endNight
11111123486%
1440
July1st to 10thNight
111222235%82%
1440
11th to 20thNight
111112335%82%
1505
21st to endNight
1112212235%80%
1849
August1st to 10thNight
121111232482%
1790
11th to 20thNight
11111223384%
1780
21st to endNight
11111123387%
1980
September1st to 10thNight
211111213384%
1800
11th to 20thNight
111111212386%
1873
21st to endNight
11111213484%
1980
October1st to 10thNight
311221223479%
2017
11th to 20thNight
231231333476%
2160
21st to endNight
231221223477%
2376
November1st to 10thNight
322222336%74%
2370
11th to 20thNight
3312222345%73%
2470
21st to endNight
5%313323435%67%
2470
December1st to 10thNight
8%413223446%63%
2470
11th to 20thNight
20%5%2332345%7%46%
3168
21st to endNight
13%5%245%3445%6%50%
4862

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
27%37%17%25%21%
1552
11th to 20thDay
23%310%14%25%24%
1675
21st to endDay
27%37%19%20%24%
1831
February1st to 10thDay
25%3317%26%27%
1800
11th to 20thDay
22%35%18%30%22%
1760
21st to endDay
25%5%7%19%27%17%
1480
March1st to 10thDay
30%5%8%19%19%19%
1800
11th to 20thDay
25%5%10%21%24%16%
1921
21st to endDay
23%6%10%24%25%11%
2343
April1st to 10thDay
24%5%12%24%23%12%
2160
11th to 20thDay
20%48%26%29%14%
2132
21st to endDay
18%39%26%33%11%
2160
May1st to 10thDay
21%5%9%22%28%15%
2160
11th to 20thDay
18%39%27%30%13%
2281
21st to endDay
19%410%30%29%8%
2534
June1st to 10thDay
19%5%8%23%31%14%
2520
11th to 20thDay
14%37%16%33%27%
2520
21st to endDay
9%3311%36%38%
2520
July1st to 10thDay
9%2215%27%45%
2451
11th to 20thDay
10%36%18%31%32%
2374
21st to endDay
12%37%21%32%25%
2330
August1st to 10thDay
11%3313%34%35%
2135
11th to 20thDay
8%2115%34%40%
2122
21st to endDay
9%2212%36%39%
2376
September1st to 10thDay
8%3410%30%44%
2160
11th to 20thDay
9%2314%32%40%
2085
21st to endDay
10%2314%38%33%
1980
October1st to 10thDay
13%36%18%25%35%
1940
11th to 20thDay
16%3413%28%36%
1800
21st to endDay
15%3412%26%39%
1980
November1st to 10thDay
14%3319%30%32%
1706
11th to 20thDay
17%26%14%25%36%
1710
21st to endDay
19%46%15%24%32%
1710
December1st to 10thDay
25%47%15%24%26%
1710
11th to 20thDay
38%5%5%17%20%15%
2032
21st to endDay
34%5%8%24%17%11%
2794
January1st to 10thNight
28%35%16%28%20%
2610
11th to 20thNight
21%37%18%23%28%
2423
21st to endNight
25%36%14%25%28%
2523
February1st to 10thNight
23%3416%26%28%
2160
11th to 20thNight
21%2419%27%27%
2099
21st to endNight
26%37%16%27%21%
1776
March1st to 10thNight
28%46%21%22%18%
2160
11th to 20thNight
24%5%10%18%24%20%
2034
21st to endNight
22%39%24%27%15%
2012
April1st to 10thNight
21%5%10%25%23%16%
1800
11th to 20thNight
16%5%8%23%29%19%
1779
21st to endNight
17%36%24%36%13%
1800
May1st to 10thNight
18%410%22%28%19%
1800
11th to 20thNight
15%28%28%29%17%
1616
21st to endNight
13%312%30%31%11%
1738
June1st to 10thNight
14%311%27%29%16%
1440
11th to 20thNight
9%28%20%34%27%
1440
21st to endNight
6%2314%34%42%
1440
July1st to 10thNight
9%2312%24%51%
1400
11th to 20thNight
8%35%18%34%33%
1457
21st to endNight
10%35%22%35%25%
1746
August1st to 10thNight
9%2313%32%42%
1780
11th to 20thNight
7%2211%37%41%
1780
21st to endNight
6%2111%37%43%
1980
September1st to 10thNight
8%238%30%48%
1800
11th to 20thNight
8%1311%36%40%
1873
21st to endNight
8%1313%36%39%
1980
October1st to 10thNight
12%3416%28%37%
2017
11th to 20thNight
15%3315%24%40%
2160
21st to endNight
13%4411%23%46%
2376
November1st to 10thNight
14%3414%31%34%
2370
11th to 20thNight
16%25%13%25%38%
2470
21st to endNight
21%25%17%21%34%
2470
December1st to 10thNight
23%36%16%21%31%
2470
11th to 20thNight
38%47%14%20%17%
3168
21st to endNight
34%5%7%23%19%11%
4862

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
16%10%34%30%8%1
213
11th to 20thDay
13%9%32%34%10%1
359
21st to endDay
11%15%34%29%9%2
396
February1st to 10thDay
9%11%35%32%11%3
420
11th to 20thDay
9%13%37%30%9%1
415
21st to endDay
12%14%38%27%8%1
346
March1st to 10thDay
14%16%38%24%8%
420
11th to 20thDay
13%12%37%26%10%1
420
21st to endDay
11%18%34%31%7%
462
April1st to 10thDay
9%12%35%30%12%3
420
11th to 20thDay
6%15%38%30%8%4
412
21st to endDay
6%11%34%31%15%4
420
May1st to 10thDay
10%10%28%37%10%4
423
11th to 20thDay
5%11%27%36%18%4
448
21st to endDay
6%9%34%33%15%4
485
June1st to 10thDay
47%24%36%23%6%
450
11th to 20thDay
3423%42%21%7%
450
21st to endDay
1319%45%24%8%
450
July1st to 10thDay
110%49%30%9%
446
11th to 20thDay
26%45%32%15%
444
21st to endDay
217%47%31%13%
487
August1st to 10thDay
115%47%25%11%
447
11th to 20thDay
218%50%26%13%
437
21st to endDay
2112%49%26%9%
495
September1st to 10thDay
1217%48%23%8%
450
11th to 20thDay
2325%48%18%4
450
21st to endDay
17%20%46%23%4
450
October1st to 10thDay
36%28%44%16%2
450
11th to 20thDay
15%34%40%17%3
450
21st to endDay
37%27%40%18%4
495
November1st to 10thDay
47%25%42%19%3
302
11th to 20thDay
45%34%35%20%3
270
21st to endDay
5%11%29%36%16%3
270
December1st to 10thDay
8%9%32%33%17%1
270
11th to 20thDay
8%8%32%32%16%4
228
21st to endDay
15%16%32%23%11%3
198
January1st to 10thNight
11%421%38%19%7%
760
11th to 20thNight
7%422%40%23%4
746
21st to endNight
11%5%25%39%16%4
792
February1st to 10thNight
8%419%39%23%6%
720
11th to 20thNight
8%323%38%20%7%
704
21st to endNight
11%5%22%39%19%4
592
March1st to 10thNight
10%324%40%21%3
720
11th to 20thNight
8%318%39%25%6%
720
21st to endNight
7%320%42%25%3
792
April1st to 10thNight
6%218%45%25%5%
720
11th to 20thNight
5%422%36%28%4
711
21st to endNight
4220%39%26%9%
720
May1st to 10thNight
3317%38%33%5%
720
11th to 20thNight
3215%33%39%8%
552
21st to endNight
1217%38%33%7%
576
June1st to 10thNight
218%33%48%9%
360
11th to 20thNight
17%27%55%9%
360
21st to endNight
1329%54%14%
360
July1st to 10thNight
11115%64%19%
350
11th to 20thNight
126%61%30%
413
21st to endNight
2111%57%28%
667
August1st to 10thNight
11222%57%17%
716
11th to 20thNight
11212%63%22%
712
21st to endNight
1216%58%22%
792
September1st to 10thNight
31322%51%20%
720
11th to 20thNight
22430%49%13%
720
21st to endNight
118%30%47%13%
720
October1st to 10thNight
319%41%41%6%
720
11th to 20thNight
3113%38%36%9%
720
21st to endNight
3313%37%32%11%
792
November1st to 10thNight
4215%40%29%10%
740
11th to 20thNight
5%214%39%32%8%
760
21st to endNight
6%121%40%25%6%
760
December1st to 10thNight
8%419%39%25%5%
760
11th to 20thNight
13%222%40%19%4
760
21st to endNight
11%422%39%17%6%
836
Page generated at 2024-01-13 20:56:39. Version ac07

Copyright 2024 Attilla Danko


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