Log Hill Mesa
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Log Hill Mesa clear sky chart from 2005-11-05 to 2017-10-31.

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
54%
15998
24%
47437
18%
15956
60%
15956
33%
27742

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%
758
23%
2366
22%
755
59%
755
32%
1373
January16th to endNight
52%
768
26%
2496
27%
768
55%
768
28%
1509
February1st to 15thNight
44%
697
18%
2288
17%
696
48%
696
23%
1455
February16th to endNight
35%
632
26%
1928
15%
632
47%
632
27%
1176
March1st to 15thNight
45%
720
24%
1980
15%
720
53%
720
33%
1187
March16th to endNight
44%
765
23%
2109
14%
765
51%
765
30%
1328
April1st to 15thNight
34%
539
18%
1798
14%
539
41%
539
23%
1110
April16th to endNight
37%
540
21%
1800
14%
540
48%
540
23%
1085
May1st to 15thNight
45%
540
21%
1645
15%
539
51%
539
30%
973
May16th to endNight
48%
562
23%
1540
14%
561
56%
561
36%
888
June1st to 15thNight
58%
540
29%
1440
18%
540
65%
540
53%
717
June16th to endNight
70%
540
30%
1440
23%
540
76%
540
58%
710
July1st to 15thNight
75%
510
17%
1422
14%
510
76%
510
33%
880
July16th to endNight
78%
564
14%
1593
13%
531
79%
531
27%
1019
August1st to 15thNight
80%
539
17%
1611
16%
536
81%
536
35%
912
August16th to endNight
77%
573
25%
1893
26%
573
78%
573
35%
1053
September1st to 15thNight
74%
540
25%
1800
23%
540
80%
540
35%
991
September16th to endNight
68%
663
36%
1980
27%
663
76%
663
50%
977
October1st to 15thNight
53%
720
28%
2160
19%
720
61%
720
43%
1116
October16th to endNight
63%
768
35%
2304
25%
768
70%
768
44%
1186
November1st to 15thNight
55%
760
29%
2160
20%
760
61%
760
38%
1217
November16th to endNight
50%
900
27%
2476
19%
900
56%
900
40%
1394
December1st to 15thNight
43%
900
16%
2520
10%
900
48%
900
29%
1599
December16th to endNight
39%
960
18%
2688
13%
960
43%
960
21%
1887

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
46%35%5%345%5%7%48%
48308
Night
26%2442445%7%55%
47628
TransparencyDay
37%7%11%19%17%5%
47998
Night
29%7%13%22%20%6%
47439
SeeingDay
10%21%30%23%11%3
5807
Night
6%11%23%30%23%4
16007

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
111%37%6%2345%6%48%
1581
16th to endDay
29%47%323446%51%
1728
February1st to 15thDay
411%5%8%5%25%345%42%
1575
16th to endDay
10%6%8%5%3445%7%42%
1542
March1st to 15thDay
210%47%424446%49%
1980
16th to endDay
18%46%425%6%6%7%45%
2115
April1st to 15thDay
310%36%42445%7%46%
2150
16th to endDay
411%35%5%34348%44%
2160
May1st to 15thDay
5%7%26%5%35%5%5%8%42%
2303
16th to endDay
3425%5%45%5%6%7%49%
2570
June1st to 15thDay
321432445%7%59%
2520
16th to endDay
2213324447%63%
2520
July1st to 15thDay
4425%6%47%8%7%8%40%
2449
16th to endDay
7%436%7%5%8%8%8%9%29%
2467
August1st to 15thDay
8%6%26%7%46%7%7%7%35%
2340
16th to endDay
5%426%6%47%6%7%9%40%
2309
September1st to 15thDay
6%325%5%45%5%5%8%44%
2160
16th to endDay
5%4235%24345%58%
1977
October1st to 15thDay
6%41341335%6%57%
1800
16th to endDay
46%12423345%62%
1918
November1st to 15thDay
26%13322346%61%
1686
16th to endDay
15%35%21344463%
1482
December1st to 15thDay
211%5%8%6%2335%446%
1440
16th to endDay
210%49%7%46%5%5%440%
1536
January1st to 15thNight
8%36%434335%55%
2366
16th to endNight
210%46%423346%51%
2496
February1st to 15thNight
39%5%7%5%33336%47%
2277
16th to endNight
110%46%43445%5%48%
1928
March1st to 15thNight
17%3442445%7%54%
1980
16th to endNight
28%35%324447%52%
2109
April1st to 15thNight
27%45%4345%7%7%48%
1798
16th to endNight
410%45%42445%7%48%
1800
May1st to 15thNight
45%234245%5%8%53%
1645
16th to endNight
321333445%10%58%
1540
June1st to 15thNight
11121235%7%71%
1440
16th to endNight
11213446%71%
1440
July1st to 15thNight
2113425%6%8%11%50%
1507
16th to endNight
2245%47%7%8%13%42%
1701
August1st to 15thNight
2212435%5%6%8%57%
1620
16th to endNight
32133346%7%9%55%
1893
September1st to 15thNight
2213325%6%6%10%54%
1800
16th to endNight
321221244470%
1980
October1st to 15thNight
4312313237%65%
2160
16th to endNight
35%1321233467%
2304
November1st to 15thNight
36%1332335%7%59%
2160
16th to endNight
17%35%222236%61%
2476
December1st to 15thNight
28%36%424447%50%
2520
16th to endNight
28%5%8%8%345%45%41%
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
37%7%16%25%9%2
1582
16th to endDay
36%6%13%23%15%3
1728
February1st to 15thDay
44%6%14%18%12%3
1575
16th to endDay
43%6%7%24%15%2
1542
March1st to 15thDay
38%6%13%23%15%1
1980
16th to endDay
38%8%11%24%14%2
2115
April1st to 15thDay
39%7%10%21%16%4
2150
16th to endDay
42%6%11%22%15%1
2160
May1st to 15thDay
42%8%10%21%16%
2303
16th to endDay
35%6%12%21%20%4
2573
June1st to 15thDay
26%5%8%18%25%15%
2520
16th to endDay
22%5%8%13%30%19%
2520
July1st to 15thDay
41%11%13%9%13%11%
2305
16th to endDay
50%14%13%11%8%2
2312
August1st to 15thDay
50%11%10%9%11%5%
2325
16th to endDay
43%11%11%15%15%3
2309
September1st to 15thDay
40%9%9%12%20%7%
2160
16th to endDay
31%6%9%19%27%6%
1977
October1st to 15thDay
29%5%8%24%24%7%
1800
16th to endDay
26%5%8%27%25%4
1918
November1st to 15thDay
27%5%11%23%25%6%
1686
16th to endDay
24%5%11%30%20%6%
1482
December1st to 15thDay
40%8%12%24%12%
1440
16th to endDay
48%9%12%18%9%2
1536
January1st to 15thNight
31%6%15%24%18%2
2366
16th to endNight
37%5%9%25%17%4
2496
February1st to 15thNight
40%6%12%21%14%3
2288
16th to endNight
36%5%11%23%18%3
1928
March1st to 15thNight
30%6%13%26%20%2
1980
16th to endNight
34%6%11%26%18%2
2109
April1st to 15thNight
35%9%13%19%18%4
1798
16th to endNight
36%6%11%24%16%3
1800
May1st to 15thNight
30%9%11%28%18%1
1646
16th to endNight
25%8%14%26%20%3
1541
June1st to 15thNight
13%6%10%21%31%16%
1440
16th to endNight
14%48%14%32%24%
1440
July1st to 15thNight
27%13%14%14%16%13%
1422
16th to endNight
32%14%21%16%9%6%
1593
August1st to 15thNight
24%11%19%17%17%9%
1611
16th to endNight
25%10%16%22%19%5%
1893
September1st to 15thNight
25%10%15%16%23%8%
1800
16th to endNight
17%5%11%25%33%7%
1980
October1st to 15thNight
20%5%13%22%28%8%
2160
16th to endNight
22%49%28%29%5%
2304
November1st to 15thNight
26%6%11%21%26%7%
2160
16th to endNight
26%5%11%26%22%8%
2476
December1st to 15thNight
33%9%15%21%18%1
2520
16th to endNight
44%9%12%20%10%2
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
17%16%26%20%16%2
90
16th to endDay
6%15%42%23%9%2
96
February1st to 15thDay
13%23%27%24%11%
90
16th to endDay
11%29%28%18%11%1
81
March1st to 15thDay
12%35%26%20%4
270
16th to endDay
11%43%29%12%2
288
April1st to 15thDay
17%35%29%13%21
269
16th to endDay
21%37%27%11%1
270
May1st to 15thDay
14%33%31%15%3
288
16th to endDay
10%24%30%18%11%4
471
June1st to 15thDay
6%15%34%24%15%4
495
16th to endDay
210%31%28%20%6%
495
July1st to 15thDay
8%7%26%29%22%5%
409
16th to endDay
10%6%33%30%15%3
327
August1st to 15thDay
14%6%31%32%10%3
315
16th to endDay
7%7%33%36%12%3
332
September1st to 15thDay
9%17%36%22%11%3
315
16th to endDay
10%21%33%26%44
261
October1st to 15thDay
8%27%23%21%15%3
135
16th to endDay
6%20%29%26%13%2
144
November1st to 15thDay
221%23%27%23%2
90
16th to endDay
7%40%26%20%5%
90
December1st to 15thDay
16%34%25%21%2
90
16th to endDay
6%29%29%27%7%1
96
January1st to 15thNight
6%12%22%33%19%5%
759
16th to endNight
7%11%24%29%20%5%
768
February1st to 15thNight
7%11%28%35%14%2
704
16th to endNight
6%18%36%27%11%
632
March1st to 15thNight
6%15%29%28%17%2
720
16th to endNight
6%18%28%29%16%1
765
April1st to 15thNight
8%20%34%25%10%
539
16th to endNight
12%18%27%25%12%2
540
May1st to 15thNight
7%12%32%31%14%2
540
16th to endNight
6%10%29%27%20%4
563
June1st to 15thNight
29%27%31%25%4
540
16th to endNight
1419%37%30%5%
540
July1st to 15thNight
312%37%40%4
510
16th to endNight
328%27%50%8%
564
August1st to 15thNight
326%34%43%8%
539
16th to endNight
4212%29%41%10%
573
September1st to 15thNight
2216%35%36%6%
540
16th to endNight
48%16%28%29%11%
663
October1st to 15thNight
6%12%24%28%21%5%
720
16th to endNight
7%8%18%30%27%7%
768
November1st to 15thNight
7%13%20%29%23%4
760
16th to endNight
8%14%24%28%19%5%
900
December1st to 15thNight
8%16%28%29%13%2
900
16th to endNight
7%16%28%30%14%2
960
Page generated at 2017-11-01 15:23:35. Version ac04

Copyright 2017 A. Danko


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