State Camp
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the State Camp clear sky chart from 2005-11-06 to 2024-01-13.

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
32%
23123
15%
74764
9%
23072
40%
23072
17%
51895

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
13%
758
13%
2649
4%
757
24%
757
10%
1921
January11th to 20thNight
19%
729
9%
2396
4%
729
26%
729
10%
1826
January21st to endNight
16%
792
12%
2574
5%
792
25%
792
10%
1933
February1st to 10thNight
15%
720
11%
2340
4%
720
25%
720
11%
1735
February11th to 20thNight
12%
703
13%
2275
3%
700
26%
700
11%
1639
February21st to endNight
15%
592
15%
1794
5%
592
28%
592
11%
1336
March1st to 10thNight
21%
720
18%
2006
8%
720
31%
720
16%
1402
March11th to 20thNight
21%
720
17%
1980
8%
720
30%
720
16%
1430
March21st to endNight
20%
792
18%
2158
6%
792
30%
792
18%
1555
April1st to 10thNight
20%
720
14%
1800
4%
720
26%
720
18%
1343
April11th to 20thNight
29%
711
15%
1775
5%
711
34%
711
22%
1268
April21st to endNight
32%
660
16%
1740
6%
660
37%
660
22%
1219
May1st to 10thNight
36%
540
14%
1620
9%
540
41%
540
18%
1153
May11th to 20thNight
40%
364
18%
1426
15%
364
48%
364
16%
923
May21st to endNight
47%
388
15%
1551
15%
388
53%
388
19%
964
June1st to 10thNight
50%
360
17%
1440
19%
360
57%
360
21%
868
June11th to 20thNight
48%
360
15%
1440
16%
360
55%
360
20%
885
June21st to endNight
51%
360
16%
1440
18%
360
59%
360
23%
855
July1st to 10thNight
56%
350
15%
1400
18%
350
60%
350
23%
819
July11th to 20thNight
64%
348
19%
1392
26%
348
66%
348
27%
773
July21st to endNight
58%
574
16%
1656
13%
542
62%
542
29%
1049
August1st to 10thNight
62%
537
17%
1600
13%
534
64%
534
30%
1009
August11th to 20thNight
56%
534
17%
1598
13%
534
59%
534
24%
1083
August21st to endNight
54%
791
19%
1979
11%
791
56%
791
30%
1349
September1st to 10thNight
49%
720
21%
1800
10%
720
54%
720
30%
1216
September11th to 20thNight
53%
720
26%
1800
18%
720
56%
720
36%
1137
September21st to endNight
45%
720
19%
2078
15%
720
49%
720
24%
1377
October1st to 10thNight
44%
720
16%
2160
14%
720
48%
720
24%
1413
October11th to 20thNight
35%
720
15%
2160
10%
720
43%
720
20%
1462
October21st to endNight
28%
792
18%
2376
11%
792
38%
792
18%
1667
November1st to 10thNight
39%
740
22%
2353
15%
740
49%
740
25%
1443
November11th to 20thNight
26%
760
16%
2614
9%
760
36%
760
14%
1801
November21st to endNight
24%
760
15%
2660
8%
760
34%
760
14%
1859
December1st to 10thNight
16%
760
9%
2660
4%
760
22%
760
9%
2055
December11th to 20thNight
21%
760
11%
3224
5%
759
29%
759
8%
2366
December21st to endNight
20%
828
7%
4850
5%
817
29%
817
6%
3762

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
17%9%47%6%45%5%5%7%32%
74675
Night
17%9%47%6%35%5%5%7%34%
75044
TransparencyDay
50%7%12%19%11%1
74391
Night
48%7%13%20%11%1
74862
SeeingDay
24%16%27%19%11%4
13595
Night
22%14%25%27%11%1
23134

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
14%11%7%9%8%45%5%5%5%27%
1517
11th to 20thDay
16%15%7%10%8%45%446%21%
1605
21st to endDay
15%15%7%12%8%46%44421%
1782
February1st to 10thDay
17%14%7%10%8%45%45%422%
1620
11th to 20thDay
15%13%6%8%8%35%45%6%27%
1573
21st to endDay
19%12%48%8%34345%28%
1460
March1st to 10thDay
15%11%47%7%45%446%34%
1949
11th to 20thDay
18%11%5%8%6%3445%6%29%
1980
21st to endDay
21%10%37%6%34446%32%
2197
April1st to 10thDay
16%11%5%7%6%3435%6%33%
2160
11th to 20thDay
18%10%45%5%25%6%5%6%34%
2134
21st to endDay
22%9%35%7%34446%34%
2236
May1st to 10thDay
21%8%37%6%345%5%7%31%
2340
11th to 20thDay
23%7%36%5%35%5%5%7%31%
2466
21st to endDay
17%6%36%5%35%5%6%8%37%
2725
June1st to 10thDay
15%6%36%6%5%6%5%6%7%35%
2520
11th to 20thDay
16%6%36%6%35%5%6%8%35%
2520
21st to endDay
14%5%35%7%36%6%6%10%36%
2520
July1st to 10thDay
10%6%37%7%5%5%6%6%8%37%
2520
11th to 20thDay
9%7%36%6%46%6%6%9%37%
2520
21st to endDay
11%7%36%6%45%6%7%8%37%
2560
August1st to 10thDay
11%6%26%7%46%6%7%10%34%
2327
11th to 20thDay
14%7%37%6%5%6%6%7%8%32%
2285
21st to endDay
15%6%36%7%5%6%6%6%8%34%
2376
September1st to 10thDay
19%6%35%5%35%446%40%
2160
11th to 20thDay
16%5%25%6%34447%44%
2156
21st to endDay
21%6%345%45%45%6%37%
1881
October1st to 10thDay
16%8%37%5%345%6%8%36%
1800
11th to 20thDay
21%7%36%6%35%5%5%5%33%
1800
21st to endDay
21%8%37%7%45%5%5%6%30%
1980
November1st to 10thDay
12%8%37%7%3445%6%41%
1725
11th to 20thDay
16%12%48%6%45%46%6%29%
1563
21st to endDay
19%14%37%6%34447%28%
1520
December1st to 10thDay
19%14%7%10%8%45%446%20%
1520
11th to 20thDay
20%13%5%9%6%345%5%6%24%
1906
21st to endDay
25%16%5%10%7%44345%16%
2772
January1st to 10thNight
15%11%6%8%6%35%5%5%8%26%
2649
11th to 20thNight
19%12%5%9%5%45%5%6%7%23%
2396
21st to endNight
13%13%5%10%7%5%5%5%46%26%
2574
February1st to 10thNight
17%11%6%8%7%45%5%5%6%27%
2340
11th to 20thNight
16%10%5%7%6%45%6%5%7%29%
2273
21st to endNight
19%10%49%6%45%445%29%
1794
March1st to 10thNight
15%7%37%6%46%5%6%7%34%
1996
11th to 20thNight
17%11%46%7%44346%34%
1979
21st to endNight
18%10%37%5%3445%6%35%
2158
April1st to 10thNight
18%12%47%6%25%447%31%
1800
11th to 20thNight
16%9%35%6%35%5%5%6%37%
1775
21st to endNight
19%7%35%5%45%5%5%7%35%
1740
May1st to 10thNight
20%9%36%5%35%5%45%35%
1620
11th to 20thNight
18%6%37%6%25%45%6%38%
1425
21st to endNight
14%7%25%6%4346%8%40%
1550
June1st to 10thNight
14%6%245%3445%8%44%
1440
11th to 20thNight
12%7%26%5%45%5%5%10%39%
1440
21st to endNight
12%5%35%5%35%5%7%9%42%
1440
July1st to 10thNight
11%6%24435%5%6%8%46%
1440
11th to 20thNight
8%435%5%36%5%6%9%47%
1440
21st to endNight
11%5%36%5%35%6%6%9%43%
1754
August1st to 10thNight
10%5%345%35%5%6%8%45%
1611
11th to 20thNight
13%6%37%6%445%5%7%40%
1598
21st to endNight
13%5%25%5%35%5%5%8%42%
1979
September1st to 10thNight
17%5%35%5%3445%6%44%
1800
11th to 20thNight
16%5%2342335%7%51%
1800
21st to endNight
18%5%26%6%3445%6%40%
2078
October1st to 10thNight
18%6%35%5%2445%7%42%
2160
11th to 20thNight
20%7%25%4345%47%39%
2160
21st to endNight
23%9%35%5%2445%8%32%
2376
November1st to 10thNight
12%8%26%4245%5%7%45%
2353
11th to 20thNight
18%10%47%5%45%5%5%7%31%
2614
21st to endNight
16%11%5%7%6%35%46%8%30%
2660
December1st to 10thNight
19%14%5%9%6%45%6%6%6%21%
2660
11th to 20thNight
19%12%48%6%46%446%27%
3288
21st to endNight
23%13%6%8%6%35%45%7%19%
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
57%6%14%16%6%1
1518
11th to 20thDay
64%7%10%12%6%1
1605
21st to endDay
65%5%10%12%7%2
1782
February1st to 10thDay
65%5%12%12%6%1
1620
11th to 20thDay
57%6%10%19%7%1
1582
21st to endDay
59%49%19%8%2
1460
March1st to 10thDay
51%5%10%23%9%1
1952
11th to 20thDay
55%5%9%19%9%3
1980
21st to endDay
54%5%8%18%13%2
2197
April1st to 10thDay
52%410%20%11%2
2160
11th to 20thDay
48%7%11%17%15%2
2134
21st to endDay
51%6%8%19%13%3
2236
May1st to 10thDay
52%6%9%19%11%2
2340
11th to 20thDay
52%7%10%17%12%3
2470
21st to endDay
43%8%16%21%10%2
2725
June1st to 10thDay
47%7%12%19%13%1
2520
11th to 20thDay
45%9%14%19%12%1
2520
21st to endDay
40%8%15%25%11%
2520
July1st to 10thDay
43%9%13%21%13%2
2450
11th to 20thDay
40%9%15%22%13%1
2445
21st to endDay
40%10%13%21%15%1
2417
August1st to 10thDay
41%10%15%23%10%
2314
11th to 20thDay
46%9%14%20%10%1
2285
21st to endDay
45%8%12%19%14%3
2376
September1st to 10thDay
46%5%10%22%14%3
2160
11th to 20thDay
39%6%11%24%19%2
2156
21st to endDay
47%6%12%19%16%1
1881
October1st to 10thDay
45%8%12%20%13%1
1800
11th to 20thDay
49%7%12%22%10%
1800
21st to endDay
53%7%13%18%8%1
1980
November1st to 10thDay
43%6%12%22%14%3
1725
11th to 20thDay
53%7%12%18%7%2
1563
21st to endDay
55%6%13%19%7%1
1520
December1st to 10thDay
66%6%12%11%5%
1520
11th to 20thDay
59%6%13%16%5%
1906
21st to endDay
69%8%10%11%2
2772
January1st to 10thNight
54%8%12%19%7%1
2649
11th to 20thNight
58%8%15%14%5%1
2396
21st to endNight
57%6%12%15%8%1
2574
February1st to 10thNight
56%7%13%17%7%
2340
11th to 20thNight
53%7%12%19%9%
2275
21st to endNight
57%410%17%11%1
1794
March1st to 10thNight
46%8%11%24%10%1
2006
11th to 20thNight
50%6%11%19%12%2
1980
21st to endNight
50%6%8%18%15%3
2158
April1st to 10thNight
52%6%10%18%14%1
1800
11th to 20thNight
46%7%11%21%13%2
1775
21st to endNight
46%7%12%21%13%2
1740
May1st to 10thNight
50%6%10%20%11%3
1620
11th to 20thNight
46%7%11%18%17%2
1426
21st to endNight
41%8%15%20%13%3
1551
June1st to 10thNight
38%8%12%25%15%1
1440
11th to 20thNight
39%9%13%23%14%2
1440
21st to endNight
37%9%13%28%13%1
1440
July1st to 10thNight
36%8%14%24%15%2
1400
11th to 20thNight
30%10%15%24%19%1
1392
21st to endNight
34%10%18%20%17%2
1656
August1st to 10thNight
33%10%17%26%13%1
1600
11th to 20thNight
41%10%13%22%14%1
1598
21st to endNight
38%9%12%25%13%3
1979
September1st to 10thNight
40%6%11%25%15%3
1800
11th to 20thNight
33%6%14%27%19%2
1800
21st to endNight
42%6%13%22%16%1
2078
October1st to 10thNight
42%6%15%21%14%1
2160
11th to 20thNight
43%8%13%22%12%1
2160
21st to endNight
49%6%14%20%10%1
2376
November1st to 10thNight
37%6%15%23%17%2
2353
11th to 20thNight
50%6%12%19%10%2
2614
21st to endNight
51%6%15%20%7%1
2660
December1st to 10thNight
59%9%13%15%5%
2660
11th to 20thNight
57%6%12%19%6%
3288
21st to endNight
62%9%13%13%3
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
34%22%31%7%5%1
180
11th to 20thDay
35%26%26%12%1
231
21st to endDay
31%31%26%9%31
264
February1st to 10thDay
34%31%27%7%1
240
11th to 20thDay
39%25%32%3
240
21st to endDay
40%21%25%13%2
326
March1st to 10thDay
31%22%28%15%3
420
11th to 20thDay
31%23%27%14%42
420
21st to endDay
33%21%26%13%6%2
462
April1st to 10thDay
31%24%24%15%6%1
420
11th to 20thDay
28%23%21%15%9%4
412
21st to endDay
30%16%34%12%8%1
420
May1st to 10thDay
30%20%24%15%9%3
423
11th to 20thDay
25%17%27%19%8%3
447
21st to endDay
21%12%26%20%17%5%
485
June1st to 10thDay
16%14%31%25%12%2
450
11th to 20thDay
19%15%25%25%14%2
450
21st to endDay
15%13%33%25%12%3
450
July1st to 10thDay
11%9%26%28%18%9%
445
11th to 20thDay
6%9%30%31%17%7%
444
21st to endDay
14%7%33%25%15%6%
488
August1st to 10thDay
10%6%27%28%22%7%
446
11th to 20thDay
13%8%25%29%16%9%
439
21st to endDay
17%8%26%22%16%10%
495
September1st to 10thDay
20%9%21%24%18%8%
450
11th to 20thDay
17%6%22%22%24%8%
450
21st to endDay
24%11%24%21%16%4
450
October1st to 10thDay
23%12%22%20%19%4
450
11th to 20thDay
25%16%29%20%8%2
450
21st to endDay
29%18%26%19%7%1
495
November1st to 10thDay
22%17%24%21%14%2
392
11th to 20thDay
26%26%26%15%7%
223
21st to endDay
29%25%33%9%4
180
December1st to 10thDay
34%27%23%11%41
180
11th to 20thDay
38%19%27%14%2
180
21st to endDay
43%16%27%11%4
198
January1st to 10thNight
25%23%33%16%3
760
11th to 20thNight
27%19%29%20%4
729
21st to endNight
24%22%31%21%2
792
February1st to 10thNight
28%20%30%19%2
720
11th to 20thNight
29%24%32%14%1
703
21st to endNight
31%20%29%18%2
592
March1st to 10thNight
26%19%31%21%3
720
11th to 20thNight
27%20%27%21%5%1
720
21st to endNight
22%20%32%20%6%1
792
April1st to 10thNight
28%19%28%20%5%
720
11th to 20thNight
23%15%28%25%8%1
711
21st to endNight
24%13%27%30%7%
660
May1st to 10thNight
24%10%22%30%14%
540
11th to 20thNight
17%11%24%39%9%
364
21st to endNight
15%7%23%31%22%1
389
June1st to 10thNight
15%8%19%42%16%1
360
11th to 20thNight
13%7%23%39%17%
360
21st to endNight
11%426%42%17%
360
July1st to 10thNight
15%418%39%22%3
350
11th to 20thNight
6%320%43%28%1
348
21st to endNight
11%319%40%24%2
574
August1st to 10thNight
10%315%42%27%2
537
11th to 20thNight
13%6%12%37%27%4
534
21st to endNight
13%417%34%29%3
791
September1st to 10thNight
18%5%19%31%23%3
720
11th to 20thNight
17%5%19%27%27%5%
720
21st to endNight
19%9%18%30%20%4
720
October1st to 10thNight
20%10%20%28%19%3
720
11th to 20thNight
23%14%23%30%10%1
720
21st to endNight
27%16%23%27%6%
792
November1st to 10thNight
17%13%26%32%11%1
740
11th to 20thNight
27%16%24%25%6%2
760
21st to endNight
24%17%28%26%5%
760
December1st to 10thNight
28%21%30%16%5%
760
11th to 20thNight
28%17%28%22%4
760
21st to endNight
27%18%29%25%2
836
Page generated at 2024-01-10 01:25:05. Version ac07

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