Lone Star
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lone Star clear sky chart from 2005-11-05 to 2018-03-21.

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
50%
16613
22%
49158
16%
16572
57%
16572
28%
30872

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
36%
779
22%
2522
11%
776
49%
776
25%
1530
January16th to endNight
31%
832
25%
2704
15%
832
45%
832
25%
1659
February1st to 15thNight
35%
763
22%
2428
11%
761
49%
761
25%
1499
February16th to endNight
32%
683
26%
1984
13%
683
45%
683
31%
1200
March1st to 15thNight
36%
780
27%
2145
15%
780
47%
780
32%
1312
March16th to endNight
42%
792
21%
2178
12%
792
50%
792
32%
1364
April1st to 15thNight
44%
718
24%
1917
13%
718
51%
718
34%
1172
April16th to endNight
48%
696
25%
1776
13%
696
54%
696
36%
1106
May1st to 15thNight
53%
539
20%
1620
13%
539
58%
539
29%
994
May16th to endNight
62%
561
19%
1682
14%
561
64%
561
29%
1056
June1st to 15thNight
65%
540
14%
1620
12%
540
66%
540
24%
1090
June16th to endNight
71%
540
15%
1620
14%
540
71%
540
28%
1057
July1st to 15thNight
68%
510
11%
1530
10%
510
69%
510
23%
1062
July16th to endNight
73%
564
11%
1595
11%
531
75%
531
25%
1074
August1st to 15thNight
69%
539
14%
1609
13%
536
69%
536
21%
1124
August16th to endNight
63%
700
15%
1846
12%
700
63%
700
22%
1342
September1st to 15thNight
69%
720
20%
1956
18%
720
70%
720
28%
1311
September16th to endNight
55%
717
16%
1980
15%
717
57%
717
23%
1395
October1st to 15thNight
57%
720
29%
2121
27%
720
63%
720
35%
1235
October16th to endNight
56%
768
35%
2304
28%
768
67%
768
39%
1261
November1st to 15thNight
56%
760
30%
2281
24%
760
65%
760
39%
1263
November16th to endNight
44%
780
28%
2501
21%
780
56%
780
31%
1448
December1st to 15thNight
42%
780
23%
2535
16%
780
52%
780
25%
1565
December16th to endNight
37%
832
23%
2704
17%
832
46%
832
21%
1753

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
11%5%25%5%35%5%5%7%42%
49686
Night
11%5%25%42445%7%44%
49357
TransparencyDay
39%7%11%19%17%5%
49387
Night
37%6%11%18%18%7%
49160
SeeingDay
13%418%23%24%15%
6356
Night
14%5%22%32%22%3
16618

By Month

Percentage Cloud Cover SE (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
14%6%25%32435%5%45%
1746
16th to endDay
15%5%34424345%46%
1872
February1st to 15thDay
16%5%25%323346%44%
1763
16th to endDay
14%6%14424435%47%
1775
March1st to 15thDay
12%424423346%50%
2145
16th to endDay
13%5%2442445%6%44%
2173
April1st to 15thDay
10%3244245%5%7%49%
2029
16th to endDay
9%4245%25%45%8%47%
2193
May1st to 15thDay
9%5%36%5%345%5%6%43%
2331
16th to endDay
8%6%25%7%36%5%6%8%38%
2431
June1st to 15thDay
9%5%245%36%6%7%10%37%
2340
16th to endDay
5%4247%47%6%7%11%36%
2340
July1st to 15thDay
7%6%36%6%5%7%6%7%9%32%
2340
16th to endDay
7%6%36%7%5%7%7%7%10%30%
2465
August1st to 15thDay
10%5%25%7%47%7%9%10%28%
2340
16th to endDay
11%5%35%7%46%7%8%11%27%
2342
September1st to 15thDay
9%426%5%35%5%7%9%39%
2001
16th to endDay
17%6%26%5%25%5%5%6%36%
1980
October1st to 15thDay
14%424424245%51%
1839
16th to endDay
9%32431233461%
1920
November1st to 15thDay
13%413313336%55%
1907
16th to endDay
11%5%24323446%50%
1787
December1st to 15thDay
16%8%25%434345%41%
1755
16th to endDay
19%6%2442335%7%41%
1872
January1st to 15thNight
12%5%35%423445%47%
2522
16th to endNight
15%6%35%324345%46%
2704
February1st to 15thNight
16%5%14324436%46%
2419
16th to endNight
12%5%35%423346%48%
1984
March1st to 15thNight
11%5%24333447%49%
2145
16th to endNight
12%424425%45%7%48%
2178
April1st to 15thNight
10%5%2332435%7%51%
1917
16th to endNight
9%414434448%50%
1776
May1st to 15thNight
7%5%25%5%45%46%9%45%
1619
16th to endNight
8%4246%35%47%8%44%
1682
June1st to 15thNight
9%436%5%37%7%7%9%35%
1620
16th to endNight
4326%6%35%8%7%10%40%
1620
July1st to 15thNight
7%5%36%6%45%7%9%11%31%
1620
16th to endNight
5%415%7%47%6%9%13%33%
1703
August1st to 15thNight
8%5%25%5%36%8%9%11%32%
1620
16th to endNight
10%5%36%7%46%6%6%12%30%
1846
September1st to 15thNight
7%425%5%36%5%7%10%39%
1956
16th to endNight
15%7%36%5%3445%7%37%
1980
October1st to 15thNight
14%423313346%52%
2121
16th to endNight
8%424422345%58%
2304
November1st to 15thNight
11%423212245%57%
2281
16th to endNight
13%42431335%6%50%
2501
December1st to 15thNight
15%6%2442335%6%45%
2535
16th to endNight
16%7%25%424346%40%
2704

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
40%5%8%17%22%5%
1747
16th to endDay
39%36%18%22%8%
1872
February1st to 15thDay
40%47%18%22%6%
1765
16th to endDay
40%36%20%21%7%
1775
March1st to 15thDay
35%48%19%20%10%
2145
16th to endDay
40%5%10%18%19%5%
2174
April1st to 15thDay
34%5%9%19%24%7%
2029
16th to endDay
33%5%10%21%21%8%
2193
May1st to 15thDay
38%8%11%19%19%2
2331
16th to endDay
39%9%13%21%14%1
2435
June1st to 15thDay
39%8%16%23%11%
2340
16th to endDay
38%11%16%21%10%1
2340
July1st to 15thDay
43%11%15%18%7%3
2201
16th to endDay
43%12%18%16%6%1
2310
August1st to 15thDay
45%12%13%19%7%
2327
16th to endDay
47%12%14%16%8%
2342
September1st to 15thDay
40%10%12%15%16%4
2001
16th to endDay
47%6%9%15%16%4
1980
October1st to 15thDay
36%38%21%23%7%
1839
16th to endDay
28%36%18%30%13%
1920
November1st to 15thDay
31%37%19%25%11%
1907
16th to endDay
33%5%8%19%22%11%
1787
December1st to 15thDay
44%48%17%18%6%
1755
16th to endDay
42%5%9%20%16%6%
1872
January1st to 15thNight
39%48%14%24%8%
2522
16th to endNight
40%45%16%21%11%
2704
February1st to 15thNight
40%37%17%20%10%
2428
16th to endNight
36%39%19%21%9%
1984
March1st to 15thNight
35%48%19%22%10%
2145
16th to endNight
35%5%12%19%19%7%
2178
April1st to 15thNight
32%5%9%19%23%9%
1917
16th to endNight
32%5%11%19%21%8%
1776
May1st to 15thNight
35%7%13%20%20%2
1620
16th to endNight
34%9%13%26%14%1
1684
June1st to 15thNight
40%10%16%22%10%
1620
16th to endNight
34%12%18%23%9%2
1620
July1st to 15thNight
39%13%18%18%6%3
1530
16th to endNight
36%13%23%16%8%1
1595
August1st to 15thNight
40%13%17%18%8%
1609
16th to endNight
45%11%16%19%7%
1846
September1st to 15thNight
36%11%13%18%14%5%
1956
16th to endNight
46%7%11%16%14%3
1980
October1st to 15thNight
33%39%19%25%7%
2121
16th to endNight
28%37%18%27%14%
2304
November1st to 15thNight
29%38%16%28%14%
2281
16th to endNight
33%47%16%22%14%
2501
December1st to 15thNight
40%410%17%19%8%
2535
16th to endNight
44%48%18%16%7%
2704

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
16%13%40%20%8%
135
16th to endDay
18%14%34%26%6%
144
February1st to 15thDay
18%17%40%20%3
135
16th to endDay
14%12%36%26%8%2
185
March1st to 15thDay
12%10%35%27%13%
330
16th to endDay
13%5%35%26%16%3
311
April1st to 15thDay
14%10%19%22%22%10%
270
16th to endDay
10%121%24%23%17%
270
May1st to 15thDay
10%6%26%24%21%10%
288
16th to endDay
11%212%19%25%29%
331
June1st to 15thDay
13%8%19%32%25%
315
16th to endDay
7%8%25%30%27%
315
July1st to 15thDay
10%324%30%30%
305
16th to endDay
8%6%19%38%26%
326
August1st to 15thDay
16%417%31%28%
313
16th to endDay
13%6%14%33%31%
332
September1st to 15thDay
11%18%25%29%23%
315
16th to endDay
21%19%22%30%14%
314
October1st to 15thDay
20%213%29%23%10%
315
16th to endDay
9%419%24%30%11%
336
November1st to 15thDay
17%418%28%23%7%
325
16th to endDay
8%420%36%22%7%
167
December1st to 15thDay
21%428%30%12%2
135
16th to endDay
22%9%31%25%9%2
144
January1st to 15thNight
15%10%32%32%9%
780
16th to endNight
17%9%36%30%4
832
February1st to 15thNight
19%9%32%33%4
764
16th to endNight
15%8%37%32%5%
683
March1st to 15thNight
14%7%36%32%8%
780
16th to endNight
14%7%31%33%12%
792
April1st to 15thNight
14%9%28%33%13%
718
16th to endNight
12%6%27%37%16%
696
May1st to 15thNight
9%326%40%18%1
540
16th to endNight
11%214%33%32%5%
563
June1st to 15thNight
12%10%37%32%6%
540
16th to endNight
6%8%36%38%10%
540
July1st to 15thNight
10%5%32%45%6%
510
16th to endNight
7%6%31%47%6%
564
August1st to 15thNight
11%5%29%45%6%
539
16th to endNight
13%5%25%44%9%
700
September1st to 15thNight
10%7%30%43%7%
720
16th to endNight
20%111%27%34%3
717
October1st to 15thNight
18%216%29%27%5%
720
16th to endNight
11%324%28%28%3
768
November1st to 15thNight
14%420%38%19%3
760
16th to endNight
15%6%28%27%20%1
780
December1st to 15thNight
18%7%24%33%15%
780
16th to endNight
20%8%26%33%9%1
832
Page generated at 2018-03-22 11:34:20. Version ac04

Copyright 2018 A. Danko


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