Lava Springs Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lava Springs Star Party clear sky chart from 2005-11-05 to 2017-09-24.

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
56%
15555
19%
46820
17%
15515
58%
15515
28%
29520

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
44%
716
11%
2470
11%
716
47%
716
15%
1791
January16th to endNight
45%
768
13%
2496
12%
768
47%
768
18%
1782
February1st to 15thNight
43%
701
9%
2288
8%
698
46%
698
16%
1669
February16th to endNight
41%
632
13%
1929
11%
632
46%
632
20%
1328
March1st to 15thNight
49%
720
15%
2034
12%
720
53%
720
22%
1442
March16th to endNight
46%
768
15%
2112
11%
768
49%
768
24%
1471
April1st to 15thNight
46%
638
16%
1829
10%
638
50%
638
26%
1197
April16th to endNight
48%
540
21%
1620
16%
540
52%
540
29%
1010
May1st to 15thNight
59%
539
19%
1619
17%
539
61%
539
33%
954
May16th to endNight
59%
562
16%
1619
15%
561
61%
561
30%
1025
June1st to 15thNight
62%
453
18%
1353
18%
453
66%
453
36%
788
June16th to endNight
75%
360
30%
1260
35%
360
81%
360
55%
522
July1st to 15thNight
81%
340
23%
1309
32%
340
84%
340
45%
566
July16th to endNight
82%
556
28%
1585
29%
523
82%
523
56%
742
August1st to 15thNight
79%
539
28%
1611
25%
536
80%
536
48%
816
August16th to endNight
80%
573
39%
1719
33%
573
82%
573
56%
812
September1st to 15thNight
73%
672
29%
1923
24%
672
77%
672
50%
976
September16th to endNight
72%
692
33%
1914
27%
692
74%
692
49%
1022
October1st to 15thNight
62%
660
24%
1925
19%
660
66%
660
36%
1133
October16th to endNight
63%
704
27%
2153
24%
704
66%
704
33%
1261
November1st to 15thNight
56%
700
20%
2275
20%
700
58%
700
25%
1448
November16th to endNight
50%
868
16%
2488
13%
868
53%
868
26%
1657
December1st to 15thNight
41%
900
8%
2520
7%
900
43%
900
17%
1906
December16th to endNight
34%
954
9%
2769
7%
954
36%
954
13%
2202

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
8%8%35%5%2445%6%45%
48096
Night
8%9%35%42445%6%45%
47004
TransparencyDay
39%5%11%19%17%8%
47779
Night
38%5%12%20%14%7%
46821
SeeingDay
11%12%26%28%16%5%
5741
Night
12%418%39%22%3
15564

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
7%17%5%9%6%25%346%30%
1463
16th to endDay
11%17%6%7%6%2335%431%
1728
February1st to 15thDay
12%16%6%9%43344429%
1575
16th to endDay
8%17%7%11%7%24345%27%
1542
March1st to 15thDay
7%14%5%8%7%3445%6%31%
1926
16th to endDay
11%15%6%7%435%45%7%28%
2112
April1st to 15thDay
11%11%46%6%35%5%5%6%31%
2116
16th to endDay
10%12%36%6%3345%6%37%
2340
May1st to 15thDay
8%8%25%5%4445%7%43%
2331
16th to endDay
11%8%37%6%445%6%7%34%
2493
June1st to 15thDay
9%5%25%5%25%45%7%46%
2604
16th to endDay
222213336%69%
2700
July1st to 15thDay
311332335%7%64%
2567
16th to endDay
321332445%6%63%
2473
August1st to 15thDay
43332445%7%61%
2340
16th to endDay
4213323346%63%
2483
September1st to 15thDay
5%2123235%46%60%
2035
16th to endDay
8%31322334462%
1904
October1st to 15thDay
11%6%25%42445%6%46%
1704
16th to endDay
8%7%2443445%7%45%
1717
November1st to 15thDay
13%10%35%414445%41%
1584
16th to endDay
8%12%5%6%434445%39%
1458
December1st to 15thDay
11%13%8%11%8%24345%25%
1440
16th to endDay
13%16%5%9%6%24445%26%
1461
January1st to 15thNight
11%15%5%7%5%23337%33%
2470
16th to endNight
10%16%6%8%6%23335%34%
2496
February1st to 15thNight
9%15%5%8%6%2445%6%31%
2277
16th to endNight
7%13%6%8%5%24447%34%
1929
March1st to 15thNight
6%11%46%6%36%45%7%35%
2034
16th to endNight
10%12%35%4345%6%7%36%
2112
April1st to 15thNight
8%10%345%2446%7%41%
1829
16th to endNight
10%7%25%5%2445%6%46%
1620
May1st to 15thNight
6%5%25%5%2445%8%49%
1619
16th to endNight
11%6%2443436%8%43%
1618
June1st to 15thNight
6%425%4245%7%9%47%
1353
16th to endNight
4212212236%70%
1260
July1st to 15thNight
12123245%7%6%60%
1389
16th to endNight
2113313346%66%
1692
August1st to 15thNight
33123245%7%8%56%
1620
16th to endNight
2213313347%66%
1719
September1st to 15thNight
4313322336%64%
1923
16th to endNight
8%313312345%63%
1914
October1st to 15thNight
9%5%13423435%55%
1925
16th to endNight
9%6%25%3236%46%49%
2153
November1st to 15thNight
10%9%45%424436%43%
2275
16th to endNight
6%8%47%6%35%45%5%41%
2488
December1st to 15thNight
13%13%48%6%25%445%31%
2520
16th to endNight
14%16%6%10%6%3333426%
2769

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
55%7%17%13%4
1463
16th to endDay
56%6%13%15%6%1
1728
February1st to 15thDay
58%5%13%16%5%
1575
16th to endDay
59%5%12%16%41
1542
March1st to 15thDay
51%7%13%19%6%
1926
16th to endDay
55%6%11%18%8%
2112
April1st to 15thDay
51%5%12%19%9%
2116
16th to endDay
45%5%10%23%13%1
2340
May1st to 15thDay
39%5%8%26%18%2
2331
16th to endDay
45%7%9%23%12%1
2496
June1st to 15thDay
36%5%11%23%18%4
2604
16th to endDay
16%25%18%37%19%
2700
July1st to 15thDay
18%35%17%31%23%
2418
16th to endDay
19%36%14%23%33%
2317
August1st to 15thDay
21%47%13%27%26%
2325
16th to endDay
21%26%17%30%21%
2483
September1st to 15thDay
22%48%17%29%16%
2035
16th to endDay
24%39%23%29%8%
1904
October1st to 15thDay
37%5%12%26%13%3
1704
16th to endDay
36%6%15%24%16%
1717
November1st to 15thDay
43%5%14%23%10%1
1584
16th to endDay
45%5%19%19%8%1
1458
December1st to 15thDay
62%6%15%13%2
1440
16th to endDay
59%5%16%13%4
1461
January1st to 15thNight
52%8%16%16%4
2470
16th to endNight
53%416%17%5%2
2496
February1st to 15thNight
53%7%16%16%6%
2288
16th to endNight
48%5%17%21%5%1
1929
March1st to 15thNight
46%8%13%22%8%
2034
16th to endNight
44%7%14%24%8%
2112
April1st to 15thNight
40%6%16%22%11%2
1829
16th to endNight
37%5%12%24%18%
1620
May1st to 15thNight
32%6%11%29%17%3
1620
16th to endNight
37%6%12%26%14%2
1619
June1st to 15thNight
29%7%12%23%21%5%
1353
16th to endNight
15%26%15%33%25%
1260
July1st to 15thNight
19%36%19%26%24%
1309
16th to endNight
17%2414%26%35%
1585
August1st to 15thNight
20%5%6%15%22%28%
1611
16th to endNight
17%26%16%29%26%
1719
September1st to 15thNight
21%38%14%29%23%
1923
16th to endNight
23%37%26%30%9%
1914
October1st to 15thNight
31%5%14%25%17%5%
1925
16th to endNight
32%5%10%31%18%1
2153
November1st to 15thNight
41%5%12%22%14%2
2275
16th to endNight
42%6%17%22%9%1
2488
December1st to 15thNight
54%7%17%15%4
2520
16th to endNight
61%6%13%14%3
2769

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
20%316%30%20%9%
65
16th to endDay
18%10%16%30%22%1
96
February1st to 15thDay
23%6%27%18%18%4
90
16th to endDay
15%23%30%20%6%1
201
March1st to 15thDay
16%22%33%20%6%
270
16th to endDay
19%28%31%15%3
288
April1st to 15thDay
20%21%28%19%7%2
269
16th to endDay
21%21%31%17%7%1
270
May1st to 15thDay
12%13%35%27%6%4
288
16th to endDay
14%10%22%25%18%7%
394
June1st to 15thDay
11%11%23%30%18%5%
495
16th to endDay
37%21%37%24%6%
495
July1st to 15thDay
3321%37%28%4
352
16th to endDay
15%32%40%15%3
327
August1st to 15thDay
6%5%33%29%21%3
315
16th to endDay
46%23%31%23%10%
332
September1st to 15thDay
413%26%25%20%10%
315
16th to endDay
10%11%27%27%16%7%
288
October1st to 15thDay
15%10%23%20%22%7%
144
16th to endDay
20%5%18%34%16%4
96
November1st to 15thDay
6%5%17%26%24%18%
90
16th to endDay
13%18%31%30%5%1
90
December1st to 15thDay
16%7%33%35%6%
90
16th to endDay
17%13%24%28%11%4
81
January1st to 15thNight
18%418%37%19%2
720
16th to endNight
19%418%33%21%2
768
February1st to 15thNight
16%5%19%41%16%1
704
16th to endNight
11%6%28%38%14%1
632
March1st to 15thNight
10%5%23%42%15%2
720
16th to endNight
15%7%23%39%13%
768
April1st to 15thNight
12%9%23%34%17%2
638
16th to endNight
14%7%24%33%19%1
540
May1st to 15thNight
9%5%19%41%21%3
540
16th to endNight
14%314%33%27%5%
563
June1st to 15thNight
7%319%43%24%2
453
16th to endNight
6%13%43%30%5%
360
July1st to 15thNight
18%46%37%5%
340
16th to endNight
26%48%38%3
556
August1st to 15thNight
49%45%37%2
539
16th to endNight
3110%43%36%5%
573
September1st to 15thNight
6%111%38%33%8%
672
16th to endNight
9%210%35%32%8%
692
October1st to 15thNight
11%118%36%28%3
660
16th to endNight
12%115%39%26%4
704
November1st to 15thNight
12%417%40%21%3
700
16th to endNight
8%6%24%39%16%4
868
December1st to 15thNight
18%6%21%42%10%
900
16th to endNight
21%7%21%35%12%1
954
Page generated at 2017-09-25 07:02:23. Version ac04

Copyright 2017 A. Danko


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