Banning
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Banning clear sky chart from 2005-11-05 to 2017-12-04.

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
62%
16495
33%
47914
26%
16455
69%
16455
48%
24558

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
52%
716
29%
2327
23%
716
63%
716
39%
1203
January16th to endNight
50%
768
31%
2328
23%
768
61%
768
35%
1338
February1st to 15thNight
53%
698
32%
2108
26%
698
63%
698
40%
1146
February16th to endNight
43%
632
28%
1895
24%
632
52%
632
30%
1154
March1st to 15thNight
49%
720
29%
2157
23%
720
60%
720
37%
1196
March16th to endNight
52%
768
29%
2040
20%
768
60%
768
44%
1160
April1st to 15thNight
42%
719
26%
1799
12%
719
50%
719
39%
1095
April16th to endNight
46%
720
31%
1800
13%
720
54%
720
47%
1021
May1st to 15thNight
55%
559
32%
1639
20%
559
60%
559
49%
828
May16th to endNight
52%
562
29%
1685
18%
561
58%
561
45%
875
June1st to 15thNight
61%
540
31%
1620
23%
540
67%
540
59%
735
June16th to endNight
75%
540
37%
1620
30%
540
80%
540
80%
620
July1st to 15thNight
86%
510
30%
1530
26%
510
87%
510
65%
659
July16th to endNight
82%
594
31%
1621
24%
559
84%
559
54%
796
August1st to 15thNight
87%
717
37%
1790
24%
713
88%
713
76%
829
August16th to endNight
90%
764
44%
1910
29%
764
90%
764
75%
894
September1st to 15thNight
85%
720
38%
1872
29%
720
87%
720
68%
889
September16th to endNight
80%
716
46%
1980
39%
716
86%
716
71%
866
October1st to 15thNight
65%
720
37%
1980
28%
720
74%
720
55%
988
October16th to endNight
70%
768
40%
2320
37%
768
77%
768
53%
1103
November1st to 15thNight
65%
760
33%
2470
31%
760
73%
760
50%
1161
November16th to endNight
61%
780
36%
2535
36%
780
69%
780
43%
1279
December1st to 15thNight
52%
736
30%
2392
25%
736
61%
736
35%
1311
December16th to endNight
44%
768
32%
2496
26%
768
55%
768
33%
1412

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
4312212335%67%
48567
Night
4413312335%65%
48116
TransparencyDay
20%35%14%26%29%
48265
Night
22%35%14%25%28%
47919
SeeingDay
7%12%34%34%9%2
6145
Night
6%422%36%24%4
16507

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%5%1332235%5%59%
1611
16th to endDay
9%6%12323346%56%
1893
February1st to 15thDay
6%5%23322346%59%
1751
16th to endDay
10%8%36%322336%49%
1579
March1st to 15thDay
5%31231345%8%60%
1801
16th to endDay
5%5%2232345%7%57%
2181
April1st to 15thDay
6%6%23423245%57%
2149
16th to endDay
4412312236%66%
2160
May1st to 15thDay
4313312335%66%
2310
16th to endDay
3312212336%67%
2429
June1st to 15thDay
1312111236%73%
2340
16th to endDay
111121186%
2340
July1st to 15thDay
221213236%72%
2340
16th to endDay
221232445%6%64%
2434
August1st to 15thDay
1121223479%
2160
16th to endDay
11121223477%
2292
September1st to 15thDay
11221223476%
2087
16th to endDay
111211122382%
1980
October1st to 15thDay
3313212235%70%
1980
16th to endDay
3312212235%71%
1899
November1st to 15thDay
3313312245%67%
1719
16th to endDay
6%413323337%61%
1755
December1st to 15thDay
7%41232445%7%55%
1649
16th to endDay
10%5%25%312345%56%
1728
January1st to 15thNight
6%314322336%60%
2327
16th to endNight
8%6%24422435%55%
2328
February1st to 15thNight
6%7%1431323461%
2101
16th to endNight
9%9%2442344449%
1895
March1st to 15thNight
5%6%3331335%6%56%
2157
16th to endNight
35%3441245%8%57%
2040
April1st to 15thNight
48%33424346%53%
1799
16th to endNight
45%33313326%63%
1800
May1st to 15thNight
3313313437%63%
1639
16th to endNight
26%24312235%63%
1684
June1st to 15thNight
313112235%73%
1620
16th to endNight
1111288%
1620
July1st to 15thNight
111113245%75%
1620
16th to endNight
2212323346%68%
1731
August1st to 15thNight
11111122481%
1800
16th to endNight
1111112383%
1910
September1st to 15thNight
11221123377%
1872
16th to endNight
1221221382%
1980
October1st to 15thNight
241321232471%
1980
16th to endNight
23322233470%
2320
November1st to 15thNight
2423313245%67%
2470
16th to endNight
45%24312346%61%
2535
December1st to 15thNight
7%5%24423347%54%
2392
16th to endNight
9%6%25%323225%56%
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
26%46%12%28%23%
1612
16th to endDay
30%46%13%21%24%
1893
February1st to 15thDay
27%4414%25%23%
1751
16th to endDay
37%3414%25%13%
1579
March1st to 15thDay
22%47%20%25%20%
1801
16th to endDay
26%5%7%21%24%14%
2181
April1st to 15thDay
28%45%20%29%12%
2149
16th to endDay
20%37%19%29%19%
2160
May1st to 15thDay
21%27%18%27%22%
2310
16th to endDay
18%37%20%33%16%
2432
June1st to 15thDay
14%1417%29%32%
2340
16th to endDay
7%235%19%61%
2340
July1st to 15thDay
13%4411%22%43%
2201
16th to endDay
18%6%6%18%23%26%
2281
August1st to 15thDay
9%4312%27%42%
2146
16th to endDay
11%349%34%36%
2292
September1st to 15thDay
12%45%9%30%38%
2087
16th to endDay
10%229%31%44%
1980
October1st to 15thDay
17%15%12%28%33%
1980
16th to endDay
17%349%24%40%
1899
November1st to 15thDay
20%26%14%29%26%
1719
16th to endDay
24%3411%25%30%
1755
December1st to 15thDay
27%5%7%18%20%21%
1649
16th to endDay
32%37%16%24%16%
1728
January1st to 15thNight
26%35%14%22%28%
2327
16th to endNight
32%46%11%18%26%
2328
February1st to 15thNight
28%3414%22%26%
2112
16th to endNight
37%4415%23%15%
1895
March1st to 15thNight
28%45%17%22%20%
2157
16th to endNight
26%48%21%23%15%
2040
April1st to 15thNight
31%38%20%22%13%
1799
16th to endNight
24%35%18%29%18%
1800
May1st to 15thNight
21%37%19%28%20%
1640
16th to endNight
24%28%21%29%14%
1685
June1st to 15thNight
15%15%13%29%34%
1620
16th to endNight
6%26%26%57%
1620
July1st to 15thNight
10%4410%23%47%
1530
16th to endNight
17%47%19%25%24%
1621
August1st to 15thNight
8%2315%30%39%
1790
16th to endNight
8%2210%35%39%
1910
September1st to 15thNight
11%3410%30%39%
1872
16th to endNight
11%110%31%44%
1980
October1st to 15thNight
18%2314%31%29%
1980
16th to endNight
19%238%23%42%
2320
November1st to 15thNight
20%35%13%28%28%
2470
16th to endNight
24%4313%21%32%
2535
December1st to 15thNight
30%45%14%21%22%
2392
16th to endNight
32%37%13%23%18%
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
28%10%34%24%2
90
16th to endDay
16%16%34%28%31
261
February1st to 15thDay
8%21%31%30%8%
266
16th to endDay
18%27%29%21%3
238
March1st to 15thDay
10%18%35%25%7%2
270
16th to endDay
10%19%40%19%8%1
288
April1st to 15thDay
11%25%39%16%6%1
269
16th to endDay
8%27%40%17%41
270
May1st to 15thDay
10%19%35%27%42
288
16th to endDay
9%15%40%26%7%1
330
June1st to 15thDay
310%43%33%7%1
315
16th to endDay
2433%42%14%3
315
July1st to 15thDay
3125%52%12%3
305
16th to endDay
3116%56%18%4
327
August1st to 15thDay
1332%48%11%3
315
16th to endDay
324%52%13%5%
332
September1st to 15thDay
3441%39%10%
315
16th to endDay
110%40%38%8%1
315
October1st to 15thDay
5%12%43%28%9%
315
16th to endDay
7%7%29%36%15%4
255
November1st to 15thDay
410%31%30%22%1
135
16th to endDay
6%13%29%28%20%2
135
December1st to 15thDay
27%38%40%13%
100
16th to endDay
12%16%34%32%4
96
January1st to 15thNight
8%5%29%33%18%5%
720
16th to endNight
13%327%33%18%3
768
February1st to 15thNight
10%427%33%20%3
704
16th to endNight
16%7%29%30%12%4
632
March1st to 15thNight
8%8%29%33%16%3
720
16th to endNight
7%7%29%33%18%3
768
April1st to 15thNight
10%11%32%29%13%3
719
16th to endNight
8%9%33%26%16%4
720
May1st to 15thNight
5%7%28%41%14%1
560
16th to endNight
5%7%31%37%16%1
563
June1st to 15thNight
3429%45%15%1
540
16th to endNight
21%57%18%
540
July1st to 15thNight
28%52%34%1
510
16th to endNight
29%49%36%2
594
August1st to 15thNight
17%44%42%4
717
16th to endNight
25%35%46%10%
764
September1st to 15thNight
29%35%42%9%
720
16th to endNight
1214%37%36%7%
716
October1st to 15thNight
5%422%35%27%5%
720
16th to endNight
5%416%33%27%12%
768
November1st to 15thNight
4221%39%25%6%
760
16th to endNight
7%321%33%26%7%
780
December1st to 15thNight
10%5%26%33%20%3
736
16th to endNight
14%6%30%27%16%3
768
Page generated at 2017-12-05 07:19:05. Version ac04

Copyright 2017 A. Danko


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