Pioneertown Mountains Preserve
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pioneertown Mountains Preserve clear sky chart from 2005-11-05 to 2017-09-22.

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
72%
16152
39%
47023
30%
16114
80%
16114
64%
20465

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
60%
717
33%
2327
27%
716
70%
716
48%
1056
January16th to endNight
57%
768
39%
2352
27%
768
72%
768
48%
1112
February1st to 15thNight
61%
699
38%
2108
28%
698
75%
698
55%
961
February16th to endNight
57%
632
38%
1895
32%
632
69%
632
52%
893
March1st to 15thNight
61%
720
36%
2147
31%
720
74%
720
58%
952
March16th to endNight
66%
768
39%
2061
27%
768
77%
768
61%
972
April1st to 15thNight
56%
719
39%
1799
17%
719
68%
719
62%
884
April16th to endNight
62%
720
43%
1800
19%
720
73%
720
74%
810
May1st to 15thNight
71%
539
43%
1619
28%
539
78%
539
77%
609
May16th to endNight
73%
561
39%
1685
29%
561
78%
561
79%
639
June1st to 15thNight
78%
540
35%
1620
28%
540
82%
540
78%
622
June16th to endNight
84%
540
38%
1620
33%
540
86%
540
83%
611
July1st to 15thNight
88%
510
32%
1530
29%
510
88%
510
70%
631
July16th to endNight
87%
564
36%
1593
31%
531
87%
531
61%
716
August1st to 15thNight
93%
716
39%
1790
25%
713
93%
713
79%
814
August16th to endNight
92%
764
44%
1910
31%
764
92%
764
77%
878
September1st to 15thNight
91%
720
41%
1883
33%
720
93%
720
77%
836
September16th to endNight
86%
683
49%
1890
42%
683
92%
683
85%
751
October1st to 15thNight
73%
660
44%
1815
34%
660
82%
660
71%
794
October16th to endNight
77%
704
45%
2128
40%
704
85%
704
69%
864
November1st to 15thNight
73%
700
40%
2275
35%
700
85%
700
67%
882
November16th to endNight
71%
720
42%
2340
39%
720
82%
720
60%
953
December1st to 15thNight
63%
720
36%
2340
29%
720
75%
720
50%
1054
December16th to endNight
53%
768
36%
2496
27%
768
67%
768
44%
1171

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
111212235%75%
47852
Night
111112235%77%
47222
TransparencyDay
12%2416%28%35%
47548
Night
11%25%16%29%35%
47028
SeeingDay
413%29%34%15%3
5853
Night
25%17%32%32%10%
16163

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
2312213346%67%
1611
16th to endDay
3212323346%66%
1869
February1st to 15thDay
1312214246%69%
1751
16th to endDay
212323348%66%
1579
March1st to 15thDay
112112346%74%
1812
16th to endDay
112112346%74%
2160
April1st to 15thDay
2211112235%73%
2149
16th to endDay
1111126%81%
2160
May1st to 15thDay
111135%81%
2331
16th to endDay
1111122481%
2429
June1st to 15thDay
11122484%
2340
16th to endDay
21111188%
2340
July1st to 15thDay
222212335%71%
2340
16th to endDay
211222445%7%65%
2465
August1st to 15thDay
112212335%75%
2160
16th to endDay
21213235%76%
2292
September1st to 15thDay
2221333475%
2076
16th to endDay
1111111285%
1882
October1st to 15thDay
11111122479%
1815
16th to endDay
1111113481%
1739
November1st to 15thDay
11112235%78%
1584
16th to endDay
221212346%72%
1620
December1st to 15thDay
2212213349%66%
1620
16th to endDay
2312323348%65%
1728
January1st to 15thNight
1212323347%67%
2327
16th to endNight
3213313336%67%
2352
February1st to 15thNight
1212322345%71%
2101
16th to endNight
221221345%8%65%
1895
March1st to 15thNight
1211112347%71%
2147
16th to endNight
112113237%73%
2061
April1st to 15thNight
12111232477%
1799
16th to endNight
11122484%
1800
May1st to 15thNight
11225%84%
1619
16th to endNight
1112485%
1684
June1st to 15thNight
11111386%
1620
16th to endNight
111290%
1620
July1st to 15thNight
1121224477%
1620
16th to endNight
212212336%72%
1701
August1st to 15thNight
111123481%
1799
16th to endNight
11111112382%
1910
September1st to 15thNight
111123482%
1883
16th to endNight
111191%
1890
October1st to 15thNight
112122381%
1815
16th to endNight
1111122481%
2128
November1st to 15thNight
1112235%79%
2275
16th to endNight
212111245%77%
2340
December1st to 15thNight
221323348%66%
2340
16th to endNight
3312223346%67%
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
17%45%20%30%22%
1612
16th to endDay
19%36%21%27%21%
1869
February1st to 15thDay
17%26%20%29%24%
1751
16th to endDay
17%39%22%32%15%
1579
March1st to 15thDay
11%26%23%31%24%
1812
16th to endDay
12%28%24%31%20%
2160
April1st to 15thDay
14%25%19%36%22%
2149
16th to endDay
7%1420%34%31%
2160
May1st to 15thDay
7%1316%35%35%
2331
16th to endDay
8%1315%36%34%
2432
June1st to 15thDay
6%129%22%57%
2340
16th to endDay
7%412%73%
2340
July1st to 15thDay
14%229%20%50%
2201
16th to endDay
16%46%16%23%31%
2310
August1st to 15thDay
10%2310%20%51%
2146
16th to endDay
11%2311%26%43%
2292
September1st to 15thDay
12%339%24%45%
2076
16th to endDay
8%117%28%52%
1882
October1st to 15thDay
10%2311%34%37%
1815
16th to endDay
9%1312%29%42%
1739
November1st to 15thDay
10%15%18%33%29%
1584
16th to endDay
14%25%18%30%28%
1620
December1st to 15thDay
17%310%22%25%20%
1620
16th to endDay
19%410%24%24%16%
1728
January1st to 15thNight
17%46%19%27%25%
2327
16th to endNight
19%36%20%25%24%
2352
February1st to 15thNight
15%26%21%28%25%
2112
16th to endNight
16%48%22%28%19%
1895
March1st to 15thNight
12%36%21%30%25%
2147
16th to endNight
11%37%22%34%19%
2061
April1st to 15thNight
12%35%22%32%24%
1799
16th to endNight
6%1318%41%28%
1800
May1st to 15thNight
41319%36%35%
1620
16th to endNight
5%1416%39%32%
1685
June1st to 15thNight
6%1211%20%57%
1620
16th to endNight
5%16%14%71%
1620
July1st to 15thNight
10%139%18%56%
1530
16th to endNight
13%45%17%26%33%
1593
August1st to 15thNight
6%2213%24%51%
1790
16th to endNight
8%129%30%46%
1910
September1st to 15thNight
7%2410%25%49%
1883
16th to endNight
46%31%55%
1890
October1st to 15thNight
9%2312%35%36%
1815
16th to endNight
9%149%29%45%
2128
November1st to 15thNight
9%1414%37%31%
2275
16th to endNight
11%25%20%29%30%
2340
December1st to 15thNight
16%49%20%25%23%
2340
16th to endNight
18%411%19%25%19%
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
10%15%31%35%7%
90
16th to endDay
5%27%29%26%8%2
237
February1st to 15thDay
419%36%26%10%2
266
16th to endDay
7%29%28%23%9%
238
March1st to 15thDay
6%22%28%25%14%1
270
16th to endDay
6%18%40%23%9%1
288
April1st to 15thDay
10%24%33%18%10%2
269
16th to endDay
429%35%22%6%1
270
May1st to 15thDay
416%33%32%7%4
288
16th to endDay
116%33%33%10%4
330
June1st to 15thDay
210%34%35%12%3
315
16th to endDay
35%30%36%16%8%
315
July1st to 15thDay
119%52%18%8%
305
16th to endDay
3118%46%21%9%
327
August1st to 15thDay
2225%41%20%6%
315
16th to endDay
2118%43%26%7%
332
September1st to 15thDay
3325%48%18%1
315
16th to endDay
39%25%36%22%2
280
October1st to 15thDay
113%38%33%12%
255
16th to endDay
210%31%29%23%2
182
November1st to 15thDay
116%17%28%28%6%
90
16th to endDay
6%17%31%25%18%
90
December1st to 15thDay
6%15%16%40%18%2
90
16th to endDay
320%29%33%13%
96
January1st to 15thNight
38%22%33%20%10%
720
16th to endNight
48%24%32%23%7%
768
February1st to 15thNight
37%23%35%24%6%
704
16th to endNight
36%30%34%19%6%
632
March1st to 15thNight
28%23%33%24%7%
720
16th to endNight
19%19%37%24%8%
768
April1st to 15thNight
210%28%31%21%6%
719
16th to endNight
9%25%31%23%9%
720
May1st to 15thNight
7%20%38%27%6%
540
16th to endNight
320%37%29%7%
563
June1st to 15thNight
217%43%32%4
540
16th to endNight
112%39%41%5%
540
July1st to 15thNight
3330%51%10%
510
16th to endNight
3229%53%10%
564
August1st to 15thNight
226%51%18%
716
16th to endNight
2118%52%24%
764
September1st to 15thNight
1228%49%18%
720
16th to endNight
19%28%44%16%
683
October1st to 15thNight
1218%33%34%9%
660
16th to endNight
1313%30%33%17%
704
November1st to 15thNight
15%18%31%33%10%
700
16th to endNight
35%16%32%28%13%
720
December1st to 15thNight
36%21%36%23%8%
720
16th to endNight
5%12%24%29%21%5%
768
Page generated at 2017-09-23 03:43:37. Version ac04

Copyright 2017 A. Danko


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