Turlock
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Turlock clear sky chart from 2005-11-06 to 2024-01-12.

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
68%
23653
31%
74711
27%
23609
74%
23609
46%
37762

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
54%
757
17%
2642
16%
756
58%
756
25%
1623
January11th to 20thNight
61%
724
22%
2353
21%
724
66%
724
30%
1407
January21st to endNight
60%
792
24%
2574
25%
792
64%
792
30%
1535
February1st to 10thNight
61%
720
27%
2340
27%
720
67%
720
34%
1301
February11th to 20thNight
60%
700
30%
2111
29%
700
67%
700
41%
1142
February21st to endNight
57%
592
28%
1776
26%
592
63%
592
35%
1003
March1st to 10thNight
54%
720
20%
2109
18%
720
59%
720
30%
1315
March11th to 20thNight
53%
720
25%
1980
21%
720
58%
720
35%
1224
March21st to endNight
55%
792
23%
2084
15%
792
61%
792
39%
1241
April1st to 10thNight
55%
720
27%
1800
12%
720
63%
720
43%
1068
April11th to 20thNight
55%
711
32%
1779
13%
711
63%
711
50%
985
April21st to endNight
62%
720
31%
1800
14%
720
68%
720
59%
925
May1st to 10thNight
65%
720
31%
1800
17%
720
70%
720
61%
920
May11th to 20thNight
72%
420
39%
1482
34%
420
78%
420
60%
587
May21st to endNight
70%
389
35%
1552
33%
388
81%
388
58%
555
June1st to 10thNight
67%
360
33%
1440
32%
360
78%
360
57%
529
June11th to 20thNight
76%
360
40%
1440
43%
360
87%
360
79%
419
June21st to endNight
82%
360
41%
1440
48%
360
90%
360
79%
429
July1st to 10thNight
90%
350
40%
1400
49%
350
94%
350
86%
390
July11th to 20thNight
88%
385
40%
1429
45%
385
90%
385
76%
456
July21st to endNight
85%
591
39%
1674
32%
558
87%
558
73%
678
August1st to 10thNight
85%
552
41%
1617
31%
549
88%
549
79%
630
August11th to 20thNight
85%
712
39%
1780
22%
712
88%
712
83%
791
August21st to endNight
90%
792
45%
1980
29%
792
91%
792
88%
847
September1st to 10thNight
90%
720
47%
1800
32%
720
92%
720
87%
780
September11th to 20thNight
83%
720
49%
1800
36%
720
88%
720
80%
806
September21st to endNight
82%
720
45%
1996
40%
720
88%
720
77%
838
October1st to 10thNight
75%
720
35%
2160
33%
720
83%
720
62%
953
October11th to 20thNight
77%
720
41%
2160
42%
720
83%
720
63%
943
October21st to endNight
78%
792
43%
2376
44%
792
84%
792
64%
1032
November1st to 10thNight
73%
740
33%
2346
33%
740
79%
740
49%
1132
November11th to 20thNight
71%
760
31%
2470
31%
760
75%
760
45%
1220
November21st to endNight
68%
760
31%
2512
31%
760
73%
760
42%
1261
December1st to 10thNight
60%
760
22%
2660
21%
760
66%
760
30%
1491
December11th to 20thNight
56%
760
18%
3219
20%
759
61%
759
18%
2161
December21st to endNight
50%
822
12%
4830
18%
817
57%
817
13%
3145

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
6%313323345%66%
74727
Night
8%313323345%64%
74995
TransparencyDay
21%49%19%25%23%
74443
Night
22%49%19%24%21%
74800
SeeingDay
6%415%26%31%18%
14159
Night
8%316%40%30%4
23674

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
18%8%47%6%45%6%5%7%32%
1521
11th to 20thDay
12%7%26%6%35%5%5%7%43%
1630
21st to endDay
13%9%37%6%36%5%5%7%36%
1782
February1st to 10thDay
15%5%35%5%23447%47%
1620
11th to 20thDay
12%42442435%8%52%
1736
21st to endDay
14%4245%33346%52%
1480
March1st to 10thDay
12%6%25%5%35%5%5%9%42%
1849
11th to 20thDay
13%5%24425%5%5%8%47%
1980
21st to endDay
10%4244245%5%8%53%
2270
April1st to 10thDay
11%5%14424447%54%
2160
11th to 20thDay
6%323423346%63%
2129
21st to endDay
6%213222346%69%
2160
May1st to 10thDay
3213222446%71%
2160
11th to 20thDay
3212312346%74%
2406
21st to endDay
3213213346%72%
2723
June1st to 10thDay
2312213345%75%
2520
11th to 20thDay
11111122387%
2520
21st to endDay
211111112287%
2520
July1st to 10thDay
11112390%
2520
11th to 20thDay
11111222385%
2479
21st to endDay
11111232484%
2546
August1st to 10thDay
221111122285%
2311
11th to 20thDay
1111122388%
2122
21st to endDay
1111112389%
2376
September1st to 10thDay
11111111290%
2160
11th to 20thDay
111111123484%
2160
21st to endDay
21111123484%
1959
October1st to 10thDay
2222212235%77%
1800
11th to 20thDay
322322246%74%
1800
21st to endDay
5%213312337%69%
1980
November1st to 10thDay
6%324425%448%58%
1731
11th to 20thDay
8%5%24344348%55%
1710
21st to endDay
10%6%25%433348%51%
1665
December1st to 10thDay
12%7%36%5%3445%7%44%
1520
11th to 20thDay
22%10%48%7%35%5%45%29%
1928
21st to endDay
14%7%48%8%5%5%6%6%7%31%
2794
January1st to 10thNight
16%6%36%43445%7%43%
2642
11th to 20thNight
11%5%25%42445%7%49%
2353
21st to endNight
14%5%244345%47%47%
2574
February1st to 10thNight
13%5%1442335%6%54%
2340
11th to 20thNight
11%41432345%8%56%
2110
21st to endNight
13%424423246%55%
1776
March1st to 10thNight
13%6%25%435%45%6%46%
2109
11th to 20thNight
12%425%423447%50%
1980
21st to endNight
14%313323346%56%
2084
April1st to 10thNight
9%42432345%8%56%
1800
11th to 20thNight
6%31242345%6%64%
1779
21st to endNight
4212213347%70%
1800
May1st to 10thNight
3212323345%73%
1800
11th to 20thNight
4211122237%75%
1482
21st to endNight
3211112236%77%
1552
June1st to 10thNight
321221232479%
1440
11th to 20thNight
11222487%
1440
21st to endNight
1111112388%
1440
July1st to 10thNight
11121390%
1440
11th to 20thNight
2111222287%
1477
21st to endNight
111221233480%
1773
August1st to 10thNight
1112112287%
1626
11th to 20thNight
11122222485%
1780
21st to endNight
11111112290%
1980
September1st to 10thNight
11111111290%
1800
11th to 20thNight
211111122386%
1800
21st to endNight
21111122385%
1996
October1st to 10thNight
421221233477%
2160
11th to 20thNight
3212212345%76%
2160
21st to endNight
4211112335%77%
2376
November1st to 10thNight
7%313322347%65%
2346
11th to 20thNight
7%32442345%7%60%
2470
21st to endNight
9%323333346%61%
2512
December1st to 10thNight
13%5%2442345%6%51%
2660
11th to 20thNight
18%6%36%6%35%46%8%34%
3276
21st to endNight
17%5%37%7%46%5%5%6%35%
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
50%9%12%18%10%1
1521
11th to 20thDay
40%7%11%20%17%5%
1630
21st to endDay
46%8%12%16%17%2
1782
February1st to 10thDay
37%6%11%24%16%6%
1620
11th to 20thDay
31%5%14%24%21%5%
1746
21st to endDay
33%6%12%24%21%4
1480
March1st to 10thDay
37%7%12%25%17%4
1849
11th to 20thDay
34%7%12%24%20%4
1980
21st to endDay
30%7%17%22%19%5%
2270
April1st to 10thDay
31%5%11%25%19%8%
2160
11th to 20thDay
23%5%12%27%25%8%
2132
21st to endDay
18%410%31%30%7%
2160
May1st to 10thDay
14%411%24%34%12%
2160
11th to 20thDay
13%47%26%35%15%
2409
21st to endDay
14%411%29%29%12%
2724
June1st to 10thDay
13%49%23%33%20%
2520
11th to 20thDay
6%16%19%34%34%
2520
21st to endDay
8%129%31%50%
2520
July1st to 10thDay
3127%22%66%
2451
11th to 20thDay
7%148%22%58%
2404
21st to endDay
5%146%27%56%
2405
August1st to 10thDay
9%138%27%52%
2295
11th to 20thDay
4138%32%52%
2122
21st to endDay
5%129%34%50%
2376
September1st to 10thDay
5%137%26%58%
2160
11th to 20thDay
7%25%18%41%28%
2160
21st to endDay
8%2418%40%29%
1959
October1st to 10thDay
11%37%20%29%30%
1800
11th to 20thDay
13%38%23%28%25%
1800
21st to endDay
18%47%22%29%20%
1980
November1st to 10thDay
25%411%24%27%9%
1731
11th to 20thDay
27%6%14%27%22%4
1710
21st to endDay
31%5%12%24%22%5%
1665
December1st to 10thDay
40%6%13%18%17%6%
1520
11th to 20thDay
56%7%9%14%12%2
1928
21st to endDay
45%13%18%15%8%1
2794
January1st to 10thNight
38%7%14%24%13%3
2642
11th to 20thNight
33%9%12%21%14%12%
2353
21st to endNight
35%6%16%16%22%5%
2574
February1st to 10thNight
32%49%26%21%9%
2340
11th to 20thNight
26%412%23%27%7%
2111
21st to endNight
31%49%28%22%6%
1776
March1st to 10thNight
36%6%13%20%19%6%
2109
11th to 20thNight
33%6%10%22%22%7%
1980
21st to endNight
29%6%14%24%19%9%
2084
April1st to 10thNight
26%6%13%24%22%9%
1800
11th to 20thNight
21%5%12%26%25%11%
1779
21st to endNight
15%5%12%28%32%9%
1800
May1st to 10thNight
15%410%21%35%17%
1800
11th to 20thNight
12%36%28%35%16%
1482
21st to endNight
10%410%31%32%12%
1552
June1st to 10thNight
12%310%20%36%19%
1440
11th to 20thNight
417%17%34%36%
1440
21st to endNight
5%1210%31%52%
1440
July1st to 10thNight
3127%21%67%
1400
11th to 20thNight
6%237%25%58%
1429
21st to endNight
8%25%5%23%56%
1674
August1st to 10thNight
7%1211%26%53%
1617
11th to 20thNight
6%138%29%52%
1780
21st to endNight
4129%30%54%
1980
September1st to 10thNight
4137%25%60%
1800
11th to 20thNight
7%1318%39%31%
1800
21st to endNight
8%1416%37%33%
1996
October1st to 10thNight
13%36%18%25%34%
2160
11th to 20thNight
12%47%19%28%31%
2160
21st to endNight
12%36%19%33%26%
2376
November1st to 10thNight
20%49%25%26%16%
2346
11th to 20thNight
23%412%24%30%8%
2470
21st to endNight
25%411%25%28%9%
2512
December1st to 10thNight
33%5%12%23%18%9%
2660
11th to 20thNight
46%7%12%18%14%3
3276
21st to endNight
44%11%15%18%9%3
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
29%6%20%23%18%5%
182
11th to 20thDay
14%419%25%22%16%
344
21st to endDay
13%5%18%21%24%19%
374
February1st to 10thDay
15%7%16%20%21%21%
340
11th to 20thDay
12%8%22%26%19%13%
409
21st to endDay
12%8%22%30%22%6%
346
March1st to 10thDay
13%8%20%30%20%7%
420
11th to 20thDay
15%9%20%27%18%12%
420
21st to endDay
12%10%22%29%18%9%
462
April1st to 10thDay
14%9%22%26%19%9%
420
11th to 20thDay
7%10%25%27%19%11%
412
21st to endDay
5%7%23%31%20%15%
420
May1st to 10thDay
48%23%31%22%13%
423
11th to 20thDay
46%18%30%30%12%
448
21st to endDay
5%6%14%22%34%18%
485
June1st to 10thDay
3416%30%30%18%
450
11th to 20thDay
2416%30%35%13%
450
21st to endDay
1112%27%38%20%
450
July1st to 10thDay
426%42%28%
446
11th to 20thDay
1316%52%28%
444
21st to endDay
1322%46%28%
487
August1st to 10thDay
37%26%38%25%
447
11th to 20thDay
115%28%40%26%
437
21st to endDay
5%24%46%25%
495
September1st to 10thDay
116%27%42%22%
450
11th to 20thDay
1210%31%35%21%
450
21st to endDay
229%25%41%21%
450
October1st to 10thDay
2419%19%35%20%
450
11th to 20thDay
4413%24%30%25%
450
21st to endDay
4414%23%33%22%
495
November1st to 10thDay
7%215%22%29%24%
327
11th to 20thDay
4318%23%33%19%
270
21st to endDay
9%19%31%36%13%
248
December1st to 10thDay
18%417%25%24%12%
180
11th to 20thDay
13%417%29%20%16%
180
21st to endDay
15%6%22%24%26%7%
198
January1st to 10thNight
17%316%34%25%5%
760
11th to 20thNight
12%314%34%30%7%
724
21st to endNight
16%214%35%29%5%
792
February1st to 10thNight
14%414%36%27%5%
720
11th to 20thNight
11%5%18%33%28%5%
704
21st to endNight
13%6%17%43%18%2
592
March1st to 10thNight
14%5%19%38%22%3
720
11th to 20thNight
12%6%20%33%25%4
720
21st to endNight
13%5%20%39%22%1
792
April1st to 10thNight
10%426%36%23%1
720
11th to 20thNight
6%5%28%35%22%3
711
21st to endNight
45%25%38%25%3
720
May1st to 10thNight
3324%43%24%3
720
11th to 20thNight
4120%46%28%
420
21st to endNight
3321%45%28%
389
June1st to 10thNight
3224%47%23%1
360
11th to 20thNight
220%48%29%1
360
21st to endNight
1116%51%31%1
360
July1st to 10thNight
8%56%34%1
350
11th to 20thNight
27%52%37%1
385
21st to endNight
119%42%46%3
591
August1st to 10thNight
119%47%38%4
552
11th to 20thNight
112%50%35%3
712
21st to endNight
17%46%44%2
792
September1st to 10thNight
117%49%40%3
720
11th to 20thNight
2111%46%36%3
720
21st to endNight
2113%38%40%5%
720
October1st to 10thNight
4215%38%34%7%
720
11th to 20thNight
3313%35%38%7%
720
21st to endNight
4212%33%35%13%
792
November1st to 10thNight
7%114%34%37%7%
740
11th to 20thNight
8%212%39%33%6%
760
21st to endNight
9%214%37%32%6%
760
December1st to 10thNight
13%314%38%26%6%
760
11th to 20thNight
17%315%35%28%3
760
21st to endNight
17%6%17%37%21%2
836
Page generated at 2024-01-08 19:31:28. Version ac07

Copyright 2024 Attilla Danko


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