LVAAS South Mountain Campus
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the LVAAS South Mountain Campus clear sky chart from 2005-11-06 to 2024-03-23.

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
33%
23433
19%
80599
10%
23342
44%
23342
20%
51036

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 10thNight
17%
752
23%
4330
8%
737
36%
737
11%
2429
January11th to 20thNight
20%
760
22%
4276
6%
740
38%
740
10%
2544
January21st to endNight
19%
830
14%
4479
7%
814
37%
814
11%
2916
February1st to 10thNight
20%
760
19%
2470
7%
760
34%
760
17%
1602
February11th to 20thNight
13%
743
19%
2286
3%
740
32%
740
15%
1519
February21st to endNight
16%
628
24%
1884
7%
628
36%
628
18%
1228
March1st to 10thNight
22%
760
22%
2268
9%
760
38%
760
20%
1416
March11th to 20thNight
21%
760
22%
2090
8%
760
35%
760
21%
1391
March21st to endNight
21%
801
21%
2082
7%
801
32%
801
24%
1422
April1st to 10thNight
21%
720
18%
1800
4%
720
30%
720
21%
1235
April11th to 20thNight
26%
711
19%
1775
6%
711
32%
711
26%
1217
April21st to endNight
28%
720
20%
1800
5%
720
35%
720
27%
1207
May1st to 10thNight
27%
550
15%
1630
7%
550
33%
550
18%
1146
May11th to 20thNight
31%
354
18%
1416
10%
354
43%
354
17%
905
May21st to endNight
47%
388
15%
1551
14%
388
53%
388
19%
958
June1st to 10thNight
42%
360
18%
1440
16%
360
53%
360
20%
871
June11th to 20thNight
47%
360
15%
1440
14%
360
56%
360
22%
874
June21st to endNight
52%
360
16%
1440
17%
360
60%
360
24%
827
July1st to 10thNight
55%
350
14%
1400
17%
350
59%
350
19%
875
July11th to 20thNight
57%
348
17%
1392
20%
348
61%
348
25%
798
July21st to endNight
55%
423
16%
1514
14%
400
61%
400
25%
887
August1st to 10thNight
63%
537
16%
1600
12%
534
65%
534
28%
1030
August11th to 20thNight
55%
667
16%
1731
10%
667
56%
667
26%
1223
August21st to endNight
55%
792
17%
1980
9%
792
57%
792
31%
1340
September1st to 10thNight
48%
720
21%
1800
9%
720
54%
720
31%
1219
September11th to 20thNight
55%
720
28%
1818
19%
720
59%
720
37%
1135
September21st to endNight
46%
720
25%
1991
17%
720
54%
720
29%
1292
October1st to 10thNight
41%
720
17%
2160
13%
720
48%
720
26%
1401
October11th to 20thNight
39%
720
23%
2160
14%
720
51%
720
29%
1313
October21st to endNight
29%
792
24%
2438
13%
792
44%
792
24%
1542
November1st to 10thNight
35%
740
25%
2407
14%
740
50%
740
28%
1384
November11th to 20thNight
30%
760
25%
2470
13%
760
45%
760
22%
1519
November21st to endNight
26%
760
21%
2626
9%
760
44%
760
20%
1584
December1st to 10thNight
21%
760
18%
2660
8%
760
35%
760
15%
1752
December11th to 20thNight
23%
760
19%
3206
7%
759
39%
759
13%
2011
December21st to endNight
23%
827
12%
4789
7%
817
39%
817
10%
3024

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
16%6%35%5%35%5%5%7%39%
78661
Night
16%6%35%5%3445%7%42%
81202
TransparencyDay
43%6%12%22%14%2
78368
Night
42%6%12%23%15%2
81029
SeeingDay
23%13%28%21%11%4
14036
Night
20%11%29%28%11%1
23457

By Month

Percentage Cloud Cover NE (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 10thDay
15%8%25%5%3445%5%45%
2517
11th to 20thDay
14%10%49%6%35%45%6%32%
2566
21st to endDay
20%10%46%6%34445%34%
3124
February1st to 10thDay
16%7%35%5%45%45%8%37%
1710
11th to 20thDay
15%8%36%6%345%5%6%38%
1781
21st to endDay
20%9%36%6%2345%5%37%
1570
March1st to 10thDay
14%8%35%435%35%6%43%
1906
11th to 20thDay
15%7%45%6%35%5%5%8%38%
2090
21st to endDay
20%7%3443445%6%39%
2317
April1st to 10thDay
16%7%36%5%4445%7%38%
2160
11th to 20thDay
17%6%25%5%3345%8%40%
2134
21st to endDay
18%5%35%6%35%5%7%6%38%
2160
May1st to 10thDay
20%6%26%5%35%5%5%6%35%
2341
11th to 20thDay
21%6%245%35%5%6%7%36%
2478
21st to endDay
15%7%25%5%445%6%8%38%
2725
June1st to 10thDay
14%6%35%6%45%5%7%9%37%
2520
11th to 20thDay
14%5%35%5%46%5%8%9%36%
2520
21st to endDay
12%5%25%5%36%5%6%9%42%
2520
July1st to 10thDay
10%5%36%7%46%6%7%9%38%
2520
11th to 20thDay
8%4245%35%6%7%11%43%
2520
21st to endDay
11%6%37%6%36%6%6%9%37%
2711
August1st to 10thDay
11%436%6%46%6%6%10%38%
2327
11th to 20thDay
12%5%25%6%45%6%6%8%39%
2152
21st to endDay
14%6%25%5%345%6%9%40%
2376
September1st to 10thDay
16%5%35%445%45%8%42%
2160
11th to 20thDay
14%42432445%8%50%
2141
21st to endDay
18%6%25%5%35%5%45%41%
1966
October1st to 10thDay
18%6%244345%6%7%41%
1800
11th to 20thDay
16%5%245%44446%45%
1800
21st to endDay
21%5%26%435%35%6%40%
1917
November1st to 10thDay
13%7%34323346%51%
1671
11th to 20thDay
17%6%2343445%6%46%
1710
21st to endDay
16%6%244335%5%8%43%
1553
December1st to 10thDay
18%8%36%5%25%5%6%7%35%
1520
11th to 20thDay
21%6%3442445%6%40%
1906
21st to endDay
19%8%38%7%35%6%5%6%31%
2772
January1st to 10thNight
16%6%35%5%3445%7%43%
4429
11th to 20thNight
16%8%36%5%3445%7%39%
4377
21st to endNight
24%9%25%434446%36%
4532
February1st to 10thNight
17%8%35%43445%7%40%
2470
11th to 20thNight
16%8%46%5%345%45%40%
2284
21st to endNight
19%7%25%5%335%5%7%41%
1884
March1st to 10thNight
15%6%35%42445%7%45%
2258
11th to 20thNight
18%7%25%434445%45%
2089
21st to endNight
17%8%35%5%34447%41%
2082
April1st to 10thNight
17%7%25%5%26%45%7%39%
1800
11th to 20thNight
15%7%36%5%3445%7%42%
1775
21st to endNight
21%42442445%6%44%
1800
May1st to 10thNight
20%9%35%7%25%446%36%
1630
11th to 20thNight
18%5%36%6%345%5%5%39%
1415
21st to endNight
14%6%35%5%25%5%5%9%41%
1550
June1st to 10thNight
15%6%26%5%2446%7%43%
1440
11th to 20thNight
13%5%25%5%45%5%7%10%40%
1440
21st to endNight
11%3245%45%5%7%10%45%
1440
July1st to 10thNight
11%5%35%6%5%6%6%6%8%40%
1440
11th to 20thNight
9%4246%35%6%6%10%45%
1440
21st to endNight
10%5%245%35%6%7%10%43%
1603
August1st to 10thNight
11%5%26%6%347%7%8%41%
1611
11th to 20thNight
11%7%36%6%5%6%6%6%7%38%
1731
21st to endNight
15%5%26%5%345%6%9%40%
1980
September1st to 10thNight
16%5%245%34446%47%
1800
11th to 20thNight
13%4245%2445%6%52%
1818
21st to endNight
16%5%35%434446%46%
1991
October1st to 10thNight
19%6%35%5%33446%43%
2160
11th to 20thNight
16%6%2343335%7%48%
2160
21st to endNight
21%6%24323445%46%
2438
November1st to 10thNight
12%5%24433446%52%
2407
11th to 20thNight
17%7%25%433446%46%
2470
21st to endNight
15%5%345%25%5%6%7%43%
2626
December1st to 10thNight
19%7%35%5%445%5%6%37%
2660
11th to 20thNight
18%7%25%5%35%45%6%39%
3288
21st to endNight
19%8%37%5%34446%37%
4884

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 10thDay
40%316%27%11%3
2518
11th to 20thDay
51%5%11%19%12%2
2566
21st to endDay
52%6%11%21%9%1
3124
February1st to 10thDay
46%5%14%23%12%1
1710
11th to 20thDay
46%5%9%24%14%2
1790
21st to endDay
50%410%23%11%4
1570
March1st to 10thDay
42%5%11%27%13%3
1909
11th to 20thDay
45%5%11%21%15%3
2090
21st to endDay
47%49%20%17%3
2317
April1st to 10thDay
45%5%9%21%14%5%
2160
11th to 20thDay
41%6%11%22%16%4
2134
21st to endDay
44%6%10%20%16%4
2160
May1st to 10thDay
48%6%9%18%15%3
2341
11th to 20thDay
47%6%10%20%14%2
2482
21st to endDay
43%7%14%22%14%2
2725
June1st to 10thDay
42%8%13%23%14%1
2520
11th to 20thDay
43%8%15%22%10%2
2520
21st to endDay
38%8%14%25%14%1
2520
July1st to 10thDay
41%8%12%22%15%2
2450
11th to 20thDay
32%8%16%26%15%2
2445
21st to endDay
41%8%11%22%16%2
2559
August1st to 10thDay
39%9%14%22%15%1
2314
11th to 20thDay
40%7%14%23%15%1
2152
21st to endDay
39%8%12%21%18%3
2376
September1st to 10thDay
41%6%12%20%19%2
2160
11th to 20thDay
33%5%11%24%24%4
2141
21st to endDay
45%5%9%18%21%2
1966
October1st to 10thDay
41%7%12%23%16%2
1800
11th to 20thDay
41%5%10%25%18%1
1800
21st to endDay
45%5%9%24%16%2
1917
November1st to 10thDay
36%414%24%20%3
1671
11th to 20thDay
39%5%9%25%19%2
1710
21st to endDay
39%5%13%30%10%2
1553
December1st to 10thDay
48%7%14%20%11%1
1520
11th to 20thDay
46%416%24%10%1
1906
21st to endDay
51%7%12%22%8%
2772
January1st to 10thNight
41%5%11%29%11%3
4429
11th to 20thNight
45%413%25%11%2
4377
21st to endNight
50%5%9%25%10%2
4532
February1st to 10thNight
44%5%13%25%10%2
2470
11th to 20thNight
46%49%19%18%3
2286
21st to endNight
43%5%9%23%17%4
1884
March1st to 10thNight
40%412%25%16%3
2268
11th to 20thNight
42%5%9%23%17%3
2090
21st to endNight
43%5%9%18%19%5%
2082
April1st to 10thNight
43%5%12%21%16%4
1800
11th to 20thNight
42%6%10%21%20%2
1775
21st to endNight
41%5%10%21%18%5%
1800
May1st to 10thNight
49%6%9%17%16%2
1630
11th to 20thNight
45%7%12%16%18%3
1416
21st to endNight
41%8%16%19%14%3
1551
June1st to 10thNight
41%6%10%22%19%2
1440
11th to 20thNight
38%8%16%23%13%1
1440
21st to endNight
34%9%14%28%13%1
1440
July1st to 10thNight
40%9%14%20%15%2
1400
11th to 20thNight
34%9%15%27%13%2
1392
21st to endNight
32%11%17%21%16%2
1514
August1st to 10thNight
37%9%15%21%16%2
1600
11th to 20thNight
43%8%13%18%15%2
1731
21st to endNight
39%7%12%19%20%3
1980
September1st to 10thNight
40%6%10%21%20%3
1800
11th to 20thNight
33%6%10%22%26%4
1818
21st to endNight
40%5%8%23%23%1
1991
October1st to 10thNight
43%412%24%15%2
2160
11th to 20thNight
37%412%29%16%2
2160
21st to endNight
41%49%27%17%2
2438
November1st to 10thNight
34%5%12%25%20%4
2407
11th to 20thNight
40%49%24%18%4
2470
21st to endNight
39%5%12%28%14%2
2626
December1st to 10thNight
47%5%13%21%13%1
2660
11th to 20thNight
44%6%13%20%15%3
3288
21st to endNight
48%5%13%23%10%1
4884

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 10thDay
30%23%26%17%22
180
11th to 20thDay
34%24%28%12%11
195
21st to endDay
26%27%31%11%41
297
February1st to 10thDay
26%28%31%10%31
270
11th to 20thDay
30%22%35%11%1
389
21st to endDay
36%16%29%16%3
382
March1st to 10thDay
33%17%28%18%5%
460
11th to 20thDay
26%26%29%14%41
460
21st to endDay
31%22%28%11%7%1
470
April1st to 10thDay
25%23%30%15%6%1
420
11th to 20thDay
26%19%27%16%8%3
412
21st to endDay
31%15%32%15%43
420
May1st to 10thDay
32%16%26%16%7%3
423
11th to 20thDay
27%13%30%19%10%2
447
21st to endDay
22%7%25%21%19%5%
485
June1st to 10thDay
18%12%30%21%16%3
450
11th to 20thDay
22%9%28%24%14%4
450
21st to endDay
16%10%31%25%14%4
450
July1st to 10thDay
11%324%29%24%7%
445
11th to 20thDay
11%225%32%24%7%
444
21st to endDay
15%5%28%31%14%6%
488
August1st to 10thDay
13%5%22%30%21%9%
446
11th to 20thDay
16%319%32%20%9%
439
21st to endDay
16%426%26%18%10%
495
September1st to 10thDay
21%6%21%24%19%9%
450
11th to 20thDay
16%5%24%28%16%11%
450
21st to endDay
23%10%26%20%15%5%
450
October1st to 10thDay
27%6%25%21%14%7%
450
11th to 20thDay
20%13%29%24%12%2
450
21st to endDay
26%13%35%16%10%1
463
November1st to 10thDay
20%11%29%24%13%4
365
11th to 20thDay
24%19%29%22%5%1
370
21st to endDay
23%23%32%16%41
213
December1st to 10thDay
28%27%28%9%7%1
180
11th to 20thDay
34%23%27%11%5%
180
21st to endDay
30%19%29%13%7%2
198
January1st to 10thNight
21%19%36%20%4
760
11th to 20thNight
25%16%33%22%4
760
21st to endNight
19%19%37%22%3
836
February1st to 10thNight
22%17%35%24%3
760
11th to 20thNight
24%23%35%16%2
743
21st to endNight
25%17%37%19%3
628
March1st to 10thNight
23%18%31%23%4
760
11th to 20thNight
24%18%32%19%6%
760
21st to endNight
21%14%38%20%6%
801
April1st to 10thNight
23%19%33%20%5%
720
11th to 20thNight
20%13%36%24%7%
711
21st to endNight
24%10%33%26%6%
720
May1st to 10thNight
26%10%31%25%8%
550
11th to 20thNight
21%6%35%28%10%
354
21st to endNight
17%6%20%40%16%1
389
June1st to 10thNight
18%426%34%17%
360
11th to 20thNight
14%5%25%43%13%
360
21st to endNight
12%324%47%13%
360
July1st to 10thNight
13%415%44%23%2
350
11th to 20thNight
10%123%38%26%2
348
21st to endNight
13%323%37%22%2
423
August1st to 10thNight
12%114%46%25%3
537
11th to 20thNight
16%313%38%28%2
667
21st to endNight
16%216%39%26%2
792
September1st to 10thNight
19%321%35%19%2
720
11th to 20thNight
16%416%36%24%4
720
21st to endNight
19%5%22%33%18%3
720
October1st to 10thNight
23%5%22%30%17%4
720
11th to 20thNight
18%10%27%33%12%
720
21st to endNight
25%12%29%26%8%
792
November1st to 10thNight
16%10%33%29%12%1
740
11th to 20thNight
21%14%28%28%8%
760
21st to endNight
18%16%33%26%7%
760
December1st to 10thNight
25%16%32%22%6%1
760
11th to 20thNight
22%15%33%25%5%
760
21st to endNight
22%15%34%26%3
836
Page generated at 2024-03-19 23:31:02. Version ac07

Copyright © 2024 Attilla Danko.


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