Ridgecrest
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ridgecrest clear sky chart from 2005-11-05 to 2019-06-10.

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
71%
17957
40%
53791
32%
17920
79%
17920
64%
22756

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
71%
836
31%
2926
31%
836
77%
836
50%
1271
January16th to endNight
66%
896
38%
2818
32%
896
76%
896
51%
1299
February1st to 15thNight
65%
816
39%
2461
33%
816
76%
816
54%
1146
February16th to endNight
61%
736
38%
2207
33%
736
74%
736
53%
1023
March1st to 15thNight
60%
840
35%
2520
27%
840
74%
840
56%
1107
March16th to endNight
59%
896
39%
2353
23%
896
72%
896
63%
1110
April1st to 15thNight
54%
839
39%
2099
17%
839
66%
839
59%
1031
April16th to endNight
60%
832
40%
2080
16%
832
70%
832
70%
960
May1st to 15thNight
61%
657
42%
1917
26%
657
69%
657
73%
751
May16th to endNight
58%
657
37%
1973
24%
657
67%
657
70%
758
June1st to 15thNight
68%
478
41%
1702
35%
478
79%
478
78%
541
June16th to endNight
79%
390
42%
1560
43%
390
89%
390
84%
440
July1st to 15thNight
87%
370
38%
1480
43%
370
92%
370
66%
494
July16th to endNight
89%
557
38%
1682
35%
524
90%
524
66%
688
August1st to 15thNight
84%
765
40%
1910
24%
761
86%
761
83%
839
August16th to endNight
85%
828
45%
2070
28%
828
87%
828
82%
921
September1st to 15thNight
84%
780
46%
1992
32%
780
90%
780
78%
888
September16th to endNight
83%
776
49%
2145
40%
776
91%
776
86%
830
October1st to 15thNight
75%
780
45%
2151
35%
780
85%
780
74%
918
October16th to endNight
79%
832
46%
2571
43%
832
88%
832
73%
993
November1st to 15thNight
79%
820
42%
2665
43%
820
86%
820
67%
1044
November16th to endNight
76%
840
41%
2730
41%
840
82%
840
64%
1096
December1st to 15thNight
71%
840
38%
2730
35%
840
78%
840
53%
1194
December16th to endNight
65%
896
34%
3049
31%
896
74%
896
46%
1414

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
111112236%77%
54704
Night
111112236%76%
53987
TransparencyDay
10%2416%28%37%
54388
Night
11%25%18%29%32%
53803
SeeingDay
48%19%29%24%13%
8073
Night
25%17%39%31%4
17972

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
5%21221335%8%64%
1672
16th to endDay
4313213347%63%
2103
February1st to 15thDay
311213339%68%
2051
16th to endDay
3112213347%67%
1839
March1st to 15thDay
12211345%8%68%
2100
16th to endDay
11111235%9%71%
2571
April1st to 15thDay
1112213247%73%
2509
16th to endDay
112246%79%
2485
May1st to 15thDay
1112235%82%
2693
16th to endDay
111111225%79%
2845
June1st to 15thDay
1112485%
2782
16th to endDay
11290%
2730
July1st to 15thDay
11121223477%
2730
16th to endDay
112212236%74%
2727
August1st to 15thDay
1111111286%
2293
16th to endDay
1112485%
2484
September1st to 15thDay
111122483%
2298
16th to endDay
112388%
2145
October1st to 15thDay
11111122481%
2135
16th to endDay
11111122480%
2005
November1st to 15thDay
111112235%78%
1854
16th to endDay
211112348%72%
1890
December1st to 15thDay
1112323348%66%
1890
16th to endDay
321222345%8%64%
1873
January1st to 15thNight
2212312348%65%
2926
16th to endNight
4213212347%67%
2818
February1st to 15thNight
1213223346%69%
2461
16th to endNight
412112446%68%
2207
March1st to 15thNight
111121345%9%68%
2520
16th to endNight
1111112348%72%
2353
April1st to 15thNight
12212335%74%
2099
16th to endNight
211225%81%
2080
May1st to 15thNight
12236%82%
1917
16th to endNight
11225%84%
1972
June1st to 15thNight
1125%86%
1702
16th to endNight
11291%
1560
July1st to 15thNight
11111325%79%
1560
16th to endNight
1112233477%
1789
August1st to 15thNight
11121485%
1920
16th to endNight
11112286%
2070
September1st to 15thNight
111222384%
1992
16th to endNight
11390%
2145
October1st to 15thNight
111223481%
2151
16th to endNight
11111135%82%
2571
November1st to 15thNight
1112245%78%
2665
16th to endNight
211211237%74%
2730
December1st to 15thNight
3212212347%68%
2730
16th to endNight
321222335%7%66%
3049

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
18%210%29%29%9%
1672
16th to endDay
22%28%25%27%14%
2103
February1st to 15thDay
15%27%23%31%18%
2051
16th to endDay
17%28%24%31%14%
1839
March1st to 15thDay
13%28%24%31%19%
2100
16th to endDay
11%210%23%32%20%
2571
April1st to 15thDay
13%27%21%33%22%
2509
16th to endDay
7%15%19%35%29%
2485
May1st to 15thDay
7%1319%33%34%
2693
16th to endDay
10%1216%38%30%
2848
June1st to 15thDay
5%1210%24%55%
2782
16th to endDay
4312%77%
2730
July1st to 15thDay
10%127%14%63%
2581
16th to endDay
12%1211%22%48%
2571
August1st to 15thDay
7%6%17%67%
2279
16th to endDay
5%11424%62%
2484
September1st to 15thDay
7%117%19%62%
2298
16th to endDay
47%31%55%
2145
October1st to 15thDay
10%1313%34%38%
2135
16th to endDay
10%211%32%41%
2005
November1st to 15thDay
9%15%20%39%23%
1854
16th to endDay
11%28%23%35%19%
1890
December1st to 15thDay
16%310%26%29%13%
1890
16th to endDay
19%411%27%24%12%
1873
January1st to 15thNight
18%29%27%29%12%
2926
16th to endNight
18%27%24%28%18%
2818
February1st to 15thNight
17%28%20%29%22%
2472
16th to endNight
15%36%26%31%16%
2207
March1st to 15thNight
13%29%23%30%20%
2520
16th to endNight
11%27%28%33%16%
2353
April1st to 15thNight
12%26%25%32%19%
2099
16th to endNight
8%1322%40%22%
2080
May1st to 15thNight
6%1221%38%29%
1918
16th to endNight
6%1420%40%26%
1973
June1st to 15thNight
41213%27%50%
1702
16th to endNight
35%15%74%
1560
July1st to 15thNight
9%117%16%64%
1480
16th to endNight
11%1310%23%49%
1682
August1st to 15thNight
5%117%20%63%
1910
16th to endNight
6%1427%59%
2070
September1st to 15thNight
7%117%24%57%
1992
16th to endNight
316%32%55%
2145
October1st to 15thNight
8%1411%33%40%
2151
16th to endNight
7%1312%30%44%
2571
November1st to 15thNight
10%1319%37%28%
2665
16th to endNight
11%16%22%31%26%
2730
December1st to 15thNight
16%210%22%29%17%
2730
16th to endNight
18%5%10%25%27%13%
3049

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%8%11%28%25%11%
120
16th to endDay
10%8%15%26%23%16%
347
February1st to 15thDay
7%12%18%25%21%14%
386
16th to endDay
8%17%22%25%19%6%
342
March1st to 15thDay
8%16%20%27%19%8%
390
16th to endDay
5%16%24%29%18%4
416
April1st to 15thDay
8%17%25%21%20%6%
389
16th to endDay
415%29%28%13%8%
378
May1st to 15thDay
311%27%25%23%8%
408
16th to endDay
5%15%21%25%23%9%
458
June1st to 15thDay
27%25%25%24%14%
412
16th to endDay
16%23%25%25%18%
375
July1st to 15thDay
3314%30%25%23%
365
16th to endDay
1112%35%27%21%
391
August1st to 15thDay
2118%37%21%17%
359
16th to endDay
212%34%31%19%
396
September1st to 15thDay
1319%30%30%14%
375
16th to endDay
25%12%30%34%13%
375
October1st to 15thDay
37%24%30%26%7%
375
16th to endDay
36%11%25%31%22%
325
November1st to 15thDay
16%8%35%28%21%
180
16th to endDay
37%12%26%34%15%
180
December1st to 15thDay
2211%42%27%12%
180
16th to endDay
5%311%37%31%9%
151
January1st to 15thNight
3413%43%30%4
840
16th to endNight
5%318%41%27%2
896
February1st to 15thNight
26%18%41%27%3
824
16th to endNight
5%9%19%41%21%2
736
March1st to 15thNight
211%22%39%21%2
840
16th to endNight
210%25%36%22%1
896
April1st to 15thNight
212%27%33%22%1
839
16th to endNight
19%25%36%22%3
832
May1st to 15thNight
17%28%36%24%2
658
16th to endNight
110%26%37%22%
659
June1st to 15thNight
5%23%40%26%2
478
16th to endNight
1117%52%24%2
390
July1st to 15thNight
15%42%43%5%
370
16th to endNight
1444%44%4
557
August1st to 15thNight
11%40%42%5%
765
16th to endNight
10%33%44%10%
828
September1st to 15thNight
10%33%47%7%
780
16th to endNight
211%35%43%6%
776
October1st to 15thNight
1318%40%32%3
780
16th to endNight
1312%32%42%8%
832
November1st to 15thNight
1411%41%37%4
820
16th to endNight
2214%37%37%5%
840
December1st to 15thNight
45%12%44%29%3
840
16th to endNight
4419%42%24%3
896
Page generated at 2019-06-10 16:29:48. Version ac04

Copyright 2019 A. Danko


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