Lockwood Valley
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lockwood Valley clear sky chart from 2005-11-05 to 2017-09-16.

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%
15718
35%
46837
28%
15674
75%
15674
54%
22022

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
53%
716
28%
2437
22%
716
64%
716
38%
1243
January16th to endNight
48%
768
32%
2466
24%
768
61%
768
35%
1311
February1st to 15thNight
54%
700
33%
2102
27%
696
64%
696
43%
1096
February16th to endNight
52%
632
30%
1895
28%
632
59%
632
36%
1068
March1st to 15thNight
55%
720
26%
2142
22%
720
64%
720
41%
1122
March16th to endNight
58%
768
31%
1998
20%
768
66%
768
48%
1087
April1st to 15thNight
50%
719
31%
1799
14%
719
59%
719
49%
987
April16th to endNight
58%
720
35%
1800
15%
720
66%
720
64%
866
May1st to 15thNight
68%
659
33%
1739
19%
659
72%
659
65%
819
May16th to endNight
64%
548
33%
1672
22%
548
72%
548
61%
700
June1st to 15thNight
80%
360
36%
1440
38%
360
86%
360
64%
483
June16th to endNight
91%
360
43%
1440
51%
360
94%
360
82%
418
July1st to 15thNight
94%
340
36%
1360
42%
340
95%
340
69%
445
July16th to endNight
92%
579
40%
1605
34%
543
92%
543
72%
661
August1st to 15thNight
92%
717
39%
1790
25%
713
93%
713
84%
783
August16th to endNight
94%
764
46%
1910
30%
764
94%
764
82%
850
September1st to 15thNight
92%
720
45%
1800
34%
720
94%
720
80%
823
September16th to endNight
86%
656
47%
1807
42%
656
91%
656
80%
749
October1st to 15thNight
73%
660
38%
1892
34%
660
80%
660
59%
876
October16th to endNight
72%
704
43%
2112
40%
704
81%
704
61%
927
November1st to 15thNight
67%
700
36%
2263
33%
700
76%
700
54%
997
November16th to endNight
64%
720
35%
2340
32%
720
73%
720
50%
1078
December1st to 15thNight
58%
720
33%
2340
29%
720
67%
720
38%
1224
December16th to endNight
49%
768
29%
2688
25%
768
59%
768
31%
1409

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
3313213346%66%
47889
Night
2213324346%65%
47035
TransparencyDay
17%2417%30%26%
47577
Night
17%2418%30%26%
46848
SeeingDay
7%10%28%35%13%4
5957
Night
5%5%16%32%31%8%
15729

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%325%5%24447%54%
1498
16th to endDay
8%8%25%433245%51%
1755
February1st to 15thDay
5%7%23325%447%52%
1751
16th to endDay
7%9%25%5%24335%50%
1579
March1st to 15thDay
35%23335%5%6%8%51%
1815
16th to endDay
342442435%8%53%
2226
April1st to 15thDay
6%5%23324337%57%
2149
16th to endDay
221222435%7%64%
2160
May1st to 15thDay
2213223447%66%
2208
16th to endDay
2212224336%68%
2438
June1st to 15thDay
1112112346%73%
2520
16th to endDay
11121485%
2520
July1st to 15thDay
111212345%74%
2520
16th to endDay
211212245%74%
2450
August1st to 15thDay
1111122482%
2160
16th to endDay
11212235%79%
2292
September1st to 15thDay
1121123479%
2160
16th to endDay
1111312480%
1824
October1st to 15thDay
3212223335%68%
1736
16th to endDay
1212223435%71%
1760
November1st to 15thDay
3313322345%66%
1595
16th to endDay
3415%325%336%60%
1620
December1st to 15thDay
37%243345%6%8%50%
1617
16th to endDay
7%5%25%425%45%6%50%
1536
January1st to 15thNight
45%25%425%45%7%52%
2437
16th to endNight
6%5%25%426%45%5%51%
2466
February1st to 15thNight
45%33426%45%7%52%
2101
16th to endNight
6%5%26%5%26%445%50%
1895
March1st to 15thNight
2324447%5%6%7%50%
2142
16th to endNight
1323447%5%5%8%52%
1998
April1st to 15thNight
4323335%447%55%
1799
16th to endNight
211121435%7%68%
1800
May1st to 15thNight
211113447%69%
1739
16th to endNight
2212112235%73%
1671
June1st to 15thNight
1122236%76%
1440
16th to endNight
11390%
1440
July1st to 15thNight
1112235%79%
1440
16th to endNight
11211222480%
1715
August1st to 15thNight
11122386%
1800
16th to endNight
1211386%
1910
September1st to 15thNight
111212285%
1800
16th to endNight
1222384%
1807
October1st to 15thNight
2112424345%69%
1892
16th to endNight
1111223446%69%
2112
November1st to 15thNight
2213336%345%64%
2263
16th to endNight
2313335%45%8%58%
2340
December1st to 15thNight
4425%435%45%8%51%
2340
16th to endNight
6%6%23436%5%5%7%47%
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%25%17%29%18%
1498
16th to endDay
32%15%17%24%19%
1755
February1st to 15thDay
28%2221%27%17%
1751
16th to endDay
33%1421%27%10%
1579
March1st to 15thDay
25%38%24%21%15%
1815
16th to endDay
25%29%25%24%11%
2226
April1st to 15thDay
24%28%27%26%10%
2149
16th to endDay
16%29%26%33%11%
2160
May1st to 15thDay
15%26%22%36%14%
2208
16th to endDay
16%25%25%37%12%
2441
June1st to 15thDay
12%15%17%33%30%
2520
16th to endDay
5%117%31%51%
2520
July1st to 15thDay
10%228%23%51%
2371
16th to endDay
11%2416%31%33%
2298
August1st to 15thDay
7%110%30%48%
2146
16th to endDay
8%219%36%41%
2292
September1st to 15thDay
8%2211%31%43%
2160
16th to endDay
8%213%36%38%
1824
October1st to 15thDay
17%2319%30%27%
1736
16th to endDay
15%2313%33%30%
1760
November1st to 15thDay
18%1317%36%22%
1595
16th to endDay
23%25%17%28%23%
1620
December1st to 15thDay
26%36%18%27%16%
1617
16th to endDay
30%36%22%20%15%
1536
January1st to 15thNight
27%25%17%27%19%
2437
16th to endNight
29%2415%23%24%
2466
February1st to 15thNight
24%3320%27%19%
2112
16th to endNight
31%2321%28%12%
1895
March1st to 15thNight
23%47%23%23%18%
2142
16th to endNight
22%310%25%26%11%
1998
April1st to 15thNight
22%29%29%26%10%
1799
16th to endNight
10%29%30%34%12%
1800
May1st to 15thNight
12%27%27%37%13%
1740
16th to endNight
11%27%27%39%12%
1672
June1st to 15thNight
9%17%17%37%26%
1440
16th to endNight
428%30%53%
1440
July1st to 15thNight
8%1210%24%52%
1360
16th to endNight
9%1318%28%37%
1605
August1st to 15thNight
5%119%32%49%
1790
16th to endNight
6%19%37%44%
1910
September1st to 15thNight
7%2110%31%47%
1800
16th to endNight
5%113%41%36%
1807
October1st to 15thNight
15%2219%31%28%
1892
16th to endNight
12%2313%35%30%
2112
November1st to 15thNight
16%2315%38%22%
2263
16th to endNight
19%25%17%29%25%
2340
December1st to 15thNight
27%35%14%27%20%
2340
16th to endNight
29%46%20%22%17%
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
11%20%44%15%6%
126
16th to endDay
18%20%33%19%5%2
261
February1st to 15thDay
13%18%31%28%6%1
266
16th to endDay
15%18%33%24%6%
238
March1st to 15thDay
10%16%34%25%11%1
270
16th to endDay
10%19%32%24%11%1
288
April1st to 15thDay
16%19%31%22%7%2
269
16th to endDay
7%21%37%24%7%1
270
May1st to 15thDay
7%15%30%31%10%3
288
16th to endDay
7%10%29%36%11%5%
330
June1st to 15thDay
5%8%28%38%13%6%
315
16th to endDay
1430%36%17%10%
315
July1st to 15thDay
216%44%21%14%
305
16th to endDay
2113%44%27%10%
327
August1st to 15thDay
1320%47%18%8%
315
16th to endDay
1116%51%19%9%
332
September1st to 15thDay
2127%47%16%3
315
16th to endDay
15%31%45%14%1
256
October1st to 15thDay
6%13%36%32%10%1
255
16th to endDay
6%10%35%36%11%
272
November1st to 15thDay
45%20%29%27%10%
101
16th to endDay
10%7%34%33%13%1
90
December1st to 15thDay
6%12%15%47%14%3
89
16th to endDay
12%23%31%20%12%
64
January1st to 15thNight
7%5%24%33%19%8%
720
16th to endNight
10%9%25%33%15%6%
768
February1st to 15thNight
7%7%23%34%19%8%
704
16th to endNight
12%7%22%31%20%5%
632
March1st to 15thNight
6%9%22%36%20%4
720
16th to endNight
49%20%36%24%4
768
April1st to 15thNight
9%7%25%32%21%4
719
16th to endNight
38%25%31%25%5%
720
May1st to 15thNight
3420%36%30%5%
660
16th to endNight
46%20%28%35%5%
550
June1st to 15thNight
2210%38%39%6%
360
16th to endNight
5%43%43%6%
360
July1st to 15thNight
1124%59%13%
340
16th to endNight
117%59%19%
579
August1st to 15thNight
1329%54%11%
717
16th to endNight
1121%58%17%
764
September1st to 15thNight
429%49%15%
720
16th to endNight
18%36%40%12%
656
October1st to 15thNight
2315%39%30%8%
660
16th to endNight
2317%31%34%10%
704
November1st to 15thNight
3419%34%28%9%
700
16th to endNight
5%420%35%23%9%
720
December1st to 15thNight
7%7%18%38%23%5%
720
16th to endNight
13%9%22%33%14%6%
768
Page generated at 2017-09-16 14:07:01. Version ac04

Copyright 2017 A. Danko


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