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Lockwood Valley Road
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lockwood Valley Road clear sky chart from 2005-11-05 to 2017-09-23.

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%
15754
35%
46933
28%
15711
75%
15711
53%
22270

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
54%
716
27%
2428
23%
716
64%
716
37%
1252
January16th to endNight
51%
768
31%
2478
25%
768
62%
768
35%
1342
February1st to 15thNight
56%
700
33%
2104
27%
697
67%
697
43%
1104
February16th to endNight
51%
632
29%
1895
26%
632
59%
632
34%
1089
March1st to 15thNight
55%
720
25%
2130
21%
720
64%
720
39%
1153
March16th to endNight
57%
768
30%
2004
19%
768
66%
768
45%
1113
April1st to 15thNight
51%
719
31%
1799
13%
719
60%
719
46%
1001
April16th to endNight
56%
720
34%
1800
14%
720
64%
720
59%
892
May1st to 15thNight
65%
671
32%
1751
18%
671
70%
671
62%
847
May16th to endNight
62%
537
34%
1661
22%
537
71%
537
61%
683
June1st to 15thNight
74%
360
36%
1440
35%
360
83%
360
63%
482
June16th to endNight
90%
360
43%
1440
51%
360
93%
360
85%
407
July1st to 15thNight
95%
340
35%
1360
42%
340
96%
340
72%
437
July16th to endNight
93%
582
39%
1608
33%
546
93%
546
73%
659
August1st to 15thNight
93%
717
39%
1790
25%
713
93%
713
85%
781
August16th to endNight
94%
764
46%
1910
30%
764
94%
764
83%
847
September1st to 15thNight
93%
720
45%
1800
34%
720
94%
720
81%
812
September16th to endNight
87%
688
49%
1888
43%
688
92%
688
82%
770
October1st to 15thNight
72%
660
37%
1900
33%
660
80%
660
59%
877
October16th to endNight
72%
704
43%
2112
39%
704
82%
704
60%
929
November1st to 15thNight
68%
700
36%
2255
34%
700
76%
700
52%
1000
November16th to endNight
64%
720
34%
2340
31%
720
73%
720
46%
1110
December1st to 15thNight
59%
720
31%
2352
27%
720
68%
720
36%
1250
December16th to endNight
50%
768
29%
2688
25%
768
61%
768
30%
1433

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
3312212335%68%
47963
Night
3312213446%66%
47129
TransparencyDay
17%36%16%29%26%
47650
Night
17%36%17%29%25%
46942
SeeingDay
5%12%29%35%12%4
6000
Night
46%16%32%31%8%
15765

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%425%42335%7%54%
1509
16th to endDay
8%7%25%423336%51%
1744
February1st to 15thDay
6%6%343145%47%53%
1751
16th to endDay
8%7%24433446%51%
1579
March1st to 15thDay
44243245%5%9%52%
1827
16th to endDay
35%2432445%7%55%
2220
April1st to 15thDay
6%5%23223347%58%
2149
16th to endDay
321221245%7%66%
2160
May1st to 15thDay
322213346%69%
2198
16th to endDay
322222336%71%
2450
June1st to 15thDay
11222236%75%
2520
16th to endDay
1112387%
2520
July1st to 15thDay
11121123478%
2520
16th to endDay
212211235%77%
2446
August1st to 15thDay
111112286%
2160
16th to endDay
1111212383%
2292
September1st to 15thDay
1111112383%
2160
16th to endDay
111222383%
1907
October1st to 15thDay
3212213345%70%
1727
16th to endDay
1212222425%72%
1760
November1st to 15thDay
2412312345%66%
1603
16th to endDay
3414433347%60%
1620
December1st to 15thDay
45%243236%5%8%52%
1605
16th to endDay
8%7%333135%5%6%50%
1536
January1st to 15thNight
45%35%42345%7%53%
2428
16th to endNight
5%7%245%235%47%51%
2478
February1st to 15thNight
45%243236%6%7%52%
2101
16th to endNight
7%6%35%5%235%46%49%
1895
March1st to 15thNight
2423425%7%6%8%50%
2130
16th to endNight
2413426%5%5%8%54%
2004
April1st to 15thNight
45%23333446%59%
1799
16th to endNight
21111245%8%68%
1800
May1st to 15thNight
22111245%6%72%
1751
16th to endNight
12121235%76%
1660
June1st to 15thNight
11111335%79%
1440
16th to endNight
1291%
1440
July1st to 15thNight
111232382%
1440
16th to endNight
1111223480%
1718
August1st to 15thNight
111288%
1800
16th to endNight
11111287%
1910
September1st to 15thNight
11112286%
1800
16th to endNight
122386%
1888
October1st to 15thNight
2113312346%70%
1900
16th to endNight
1112213445%71%
2112
November1st to 15thNight
23133245%35%65%
2255
16th to endNight
341332345%9%59%
2340
December1st to 15thNight
4425%42445%7%52%
2352
16th to endNight
7%6%24325%46%7%48%
2688

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
27%26%17%26%18%
1509
16th to endDay
32%37%14%22%20%
1744
February1st to 15thDay
28%3418%27%17%
1751
16th to endDay
32%47%20%25%10%
1579
March1st to 15thDay
25%6%11%22%20%14%
1827
16th to endDay
25%5%10%25%23%10%
2220
April1st to 15thDay
24%38%27%26%10%
2149
16th to endDay
16%410%24%33%10%
2160
May1st to 15thDay
15%39%22%34%15%
2198
16th to endDay
13%38%25%35%12%
2453
June1st to 15thDay
11%27%15%33%28%
2520
16th to endDay
5%127%32%49%
2520
July1st to 15thDay
9%247%24%51%
2371
16th to endDay
11%35%15%30%33%
2293
August1st to 15thDay
7%139%31%47%
2146
16th to endDay
7%148%38%39%
2292
September1st to 15thDay
7%1311%31%43%
2160
16th to endDay
7%1311%39%36%
1907
October1st to 15thDay
16%25%19%29%25%
1727
16th to endDay
14%35%13%33%29%
1760
November1st to 15thDay
17%25%17%34%22%
1603
16th to endDay
24%17%15%26%24%
1620
December1st to 15thDay
26%5%8%16%25%16%
1605
16th to endDay
31%5%8%20%18%15%
1536
January1st to 15thNight
27%46%17%23%20%
2428
16th to endNight
29%37%13%20%25%
2478
February1st to 15thNight
24%46%19%26%19%
2112
16th to endNight
31%46%19%27%11%
1895
March1st to 15thNight
24%5%9%21%21%16%
2130
16th to endNight
22%5%12%23%25%11%
2004
April1st to 15thNight
22%310%27%25%9%
1799
16th to endNight
11%410%28%33%11%
1800
May1st to 15thNight
12%37%25%36%13%
1752
16th to endNight
10%28%25%39%12%
1661
June1st to 15thNight
8%27%17%36%26%
1440
16th to endNight
338%30%52%
1440
July1st to 15thNight
6%25%8%23%53%
1360
16th to endNight
7%35%17%28%38%
1608
August1st to 15thNight
4129%31%49%
1790
16th to endNight
6%28%36%44%
1910
September1st to 15thNight
6%139%32%46%
1800
16th to endNight
41212%43%34%
1888
October1st to 15thNight
14%2418%31%27%
1900
16th to endNight
12%3413%35%30%
2112
November1st to 15thNight
16%26%14%36%23%
2255
16th to endNight
20%37%15%27%24%
2340
December1st to 15thNight
27%48%13%25%20%
2352
16th to endNight
29%5%8%19%20%16%
2688

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
13%22%36%21%5%
137
16th to endDay
16%20%34%20%5%2
259
February1st to 15thDay
10%22%29%28%7%2
266
16th to endDay
14%22%34%22%5%1
238
March1st to 15thDay
8%22%33%25%10%
270
16th to endDay
6%25%31%24%10%1
288
April1st to 15thDay
14%23%33%17%7%2
269
16th to endDay
430%35%22%5%1
270
May1st to 15thDay
9%14%36%28%7%3
288
16th to endDay
5%10%36%33%10%3
330
June1st to 15thDay
310%32%37%11%4
315
16th to endDay
331%38%16%9%
315
July1st to 15thDay
119%47%18%12%
305
16th to endDay
2114%49%22%10%
327
August1st to 15thDay
1124%48%16%7%
315
16th to endDay
114%55%20%7%
332
September1st to 15thDay
1224%51%14%5%
315
16th to endDay
16%28%47%14%2
284
October1st to 15thDay
314%37%32%9%1
255
16th to endDay
414%32%36%10%1
272
November1st to 15thDay
48%16%32%29%9%
109
16th to endDay
8%14%27%34%13%1
90
December1st to 15thDay
8%11%19%47%12%1
87
16th to endDay
7%23%37%20%10%
64
January1st to 15thNight
8%7%22%32%20%9%
720
16th to endNight
9%12%21%32%17%5%
768
February1st to 15thNight
7%8%22%32%21%7%
704
16th to endNight
11%10%20%31%19%5%
632
March1st to 15thNight
411%23%34%21%5%
720
16th to endNight
5%10%20%34%25%3
768
April1st to 15thNight
7%10%26%32%18%4
719
16th to endNight
310%26%31%23%4
720
May1st to 15thNight
36%22%33%28%5%
672
16th to endNight
28%22%30%30%4
539
June1st to 15thNight
1316%39%34%5%
360
16th to endNight
6%43%41%6%
360
July1st to 15thNight
1119%64%13%
340
16th to endNight
117%59%19%
582
August1st to 15thNight
328%56%10%
717
16th to endNight
120%59%17%
764
September1st to 15thNight
330%49%15%
720
16th to endNight
28%36%40%11%
688
October1st to 15thNight
35%14%36%32%7%
660
16th to endNight
2416%32%33%11%
704
November1st to 15thNight
36%16%35%28%10%
700
16th to endNight
5%5%19%33%27%9%
720
December1st to 15thNight
8%7%18%38%22%6%
720
16th to endNight
12%11%21%32%17%5%
768
Page generated at 2017-09-24 06:15:48. Version ac04

Copyright 2017 A. Danko


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