Auburn
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Auburn clear sky chart from 2005-11-06 to 2024-01-10.

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
36%
24419
16%
74602
11%
24364
42%
24364
20%
51837

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
16%
950
12%
2647
4%
946
23%
946
13%
2078
January11th to 20thNight
18%
900
9%
2520
4%
900
23%
900
12%
2020
January21st to endNight
18%
900
10%
2682
4%
900
24%
900
11%
2128
February1st to 10thNight
17%
720
8%
2268
3%
720
23%
720
11%
1759
February11th to 20thNight
21%
701
14%
2099
6%
700
28%
700
14%
1568
February21st to endNight
17%
592
15%
1776
4%
592
27%
592
14%
1324
March1st to 10thNight
25%
720
14%
2160
8%
720
29%
720
17%
1548
March11th to 20thNight
30%
720
20%
2007
9%
720
39%
720
24%
1335
March21st to endNight
28%
779
17%
2165
8%
779
35%
779
19%
1563
April1st to 10thNight
31%
540
16%
1800
9%
540
40%
540
21%
1197
April11th to 20thNight
33%
533
20%
1721
11%
533
43%
533
20%
1167
April21st to endNight
32%
540
17%
1620
8%
540
40%
540
22%
1120
May1st to 10thNight
31%
540
12%
1620
7%
540
36%
540
18%
1182
May11th to 20thNight
39%
531
16%
1593
10%
531
45%
531
22%
1086
May21st to endNight
53%
583
15%
1685
11%
582
56%
582
31%
1055
June1st to 10thNight
55%
540
17%
1440
12%
540
60%
540
38%
876
June11th to 20thNight
52%
540
19%
1440
14%
540
57%
540
33%
917
June21st to endNight
53%
540
19%
1440
12%
540
59%
540
33%
929
July1st to 10thNight
62%
525
17%
1400
14%
525
65%
525
37%
865
July11th to 20thNight
64%
522
21%
1392
17%
522
67%
522
41%
813
July21st to endNight
66%
591
22%
1566
17%
558
69%
558
40%
909
August1st to 10thNight
67%
537
21%
1600
18%
534
69%
534
37%
903
August11th to 20thNight
67%
534
23%
1598
19%
534
70%
534
35%
940
August21st to endNight
68%
594
23%
1944
22%
594
71%
594
34%
1092
September1st to 10thNight
61%
586
22%
1846
19%
586
65%
586
30%
1103
September11th to 20thNight
65%
720
31%
1980
25%
720
67%
720
39%
1161
September21st to endNight
52%
720
25%
1980
19%
720
57%
720
33%
1243
October1st to 10thNight
49%
720
23%
1980
17%
720
54%
720
33%
1232
October11th to 20thNight
33%
720
19%
2146
11%
720
42%
720
20%
1461
October21st to endNight
28%
792
18%
2574
12%
792
37%
792
18%
1757
November1st to 10thNight
36%
740
22%
2406
17%
740
45%
740
25%
1489
November11th to 20thNight
27%
760
19%
2470
10%
760
38%
760
17%
1702
November21st to endNight
27%
760
14%
2470
10%
760
32%
760
14%
1816
December1st to 10thNight
20%
760
9%
2470
5%
760
24%
760
11%
1902
December11th to 20thNight
20%
931
9%
3227
4%
930
26%
930
11%
2497
December21st to endNight
16%
1038
5%
4870
3%
1026
20%
1026
5%
4100

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
14%9%47%6%45%5%6%7%34%
74852
Night
15%9%47%6%35%5%5%7%35%
74838
TransparencyDay
48%6%12%20%12%1
74559
Night
48%6%11%20%13%2
74652
SeeingDay
17%10%28%24%15%6%
14485
Night
19%9%29%29%13%1
24430

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 10thDay
17%14%6%11%8%4445%6%20%
1509
11th to 20thDay
17%19%6%12%7%45%44419%
1440
21st to endDay
15%17%10%11%8%45%436%17%
1671
February1st to 10thDay
17%13%7%11%9%46%35%6%20%
1690
11th to 20thDay
15%12%5%11%9%5%5%5%5%6%22%
1748
21st to endDay
16%14%7%9%7%245%5%7%24%
1480
March1st to 10thDay
16%11%5%8%7%36%45%6%28%
1800
11th to 20thDay
16%10%47%8%36%45%7%31%
1953
21st to endDay
22%11%48%7%45%447%24%
2205
April1st to 10thDay
16%10%5%8%6%35%5%5%7%30%
2160
11th to 20thDay
18%8%36%6%45%45%6%35%
2187
21st to endDay
18%9%36%6%3446%7%33%
2340
May1st to 10thDay
16%8%38%6%45%6%6%7%31%
2340
11th to 20thDay
19%7%36%6%4446%7%35%
2301
21st to endDay
10%6%26%6%46%6%6%10%39%
2587
June1st to 10thDay
10%5%36%5%46%5%6%8%41%
2520
11th to 20thDay
9%5%35%5%45%5%6%9%43%
2520
21st to endDay
11%5%35%7%45%6%7%9%39%
2520
July1st to 10thDay
7%5%36%5%45%5%7%9%44%
2520
11th to 20thDay
8%4245%45%6%7%9%45%
2520
21st to endDay
7%5%36%5%45%7%7%10%43%
2658
August1st to 10thDay
6%425%6%45%7%7%10%44%
2327
11th to 20thDay
9%5%26%5%46%6%8%10%41%
2303
21st to endDay
9%6%25%5%345%6%9%46%
2408
September1st to 10thDay
11%6%26%6%35%5%6%7%42%
2095
11th to 20thDay
10%4245%346%7%9%45%
1980
21st to endDay
14%6%25%5%35%45%8%44%
1980
October1st to 10thDay
13%6%26%7%35%5%5%7%42%
1980
11th to 20thDay
17%6%27%5%36%5%6%7%36%
1810
21st to endDay
19%9%37%6%5%5%5%6%6%28%
1782
November1st to 10thDay
11%8%36%4345%5%7%44%
1672
11th to 20thDay
17%13%47%6%35%35%7%31%
1710
21st to endDay
20%13%49%6%4445%6%26%
1710
December1st to 10thDay
15%15%7%11%7%46%45%5%20%
1710
11th to 20thDay
15%13%7%11%7%5%5%5%6%6%22%
1933
21st to endDay
22%21%9%12%6%34435%11%
2783
January1st to 10thNight
17%11%5%11%9%35%446%24%
2647
11th to 20thNight
18%14%5%9%8%35%5%46%23%
2520
21st to endNight
16%15%8%10%8%45%5%46%21%
2682
February1st to 10thNight
19%13%6%9%7%45%446%24%
2268
11th to 20thNight
14%12%6%8%7%45%45%6%28%
2098
21st to endNight
21%11%48%6%35%5%46%29%
1776
March1st to 10thNight
15%9%5%8%7%5%5%445%34%
2160
11th to 20thNight
13%8%36%6%35%5%5%7%40%
2007
21st to endNight
20%9%47%5%3445%5%33%
2165
April1st to 10thNight
15%7%36%435%5%6%8%37%
1800
11th to 20thNight
18%7%47%5%4445%6%37%
1721
21st to endNight
17%8%37%6%345%47%37%
1620
May1st to 10thNight
17%9%36%6%46%5%5%7%31%
1620
11th to 20thNight
20%7%35%5%3445%6%38%
1592
21st to endNight
10%5%345%35%7%6%8%44%
1684
June1st to 10thNight
9%5%245%246%6%9%48%
1440
11th to 20thNight
8%6%35%5%35%6%5%8%45%
1440
21st to endNight
8%435%6%35%5%7%9%44%
1440
July1st to 10thNight
7%426%5%345%6%9%50%
1440
11th to 20thNight
7%425%43347%9%53%
1440
21st to endNight
5%415%6%245%6%9%52%
1658
August1st to 10thNight
6%5%24435%5%5%11%49%
1611
11th to 20thNight
7%5%246%25%47%8%51%
1598
21st to endNight
8%3145%35%46%8%52%
1944
September1st to 10thNight
10%5%25%435%447%50%
1846
11th to 20thNight
11%414433347%55%
1980
21st to endNight
13%5%25%4345%5%6%48%
1980
October1st to 10thNight
11%6%35%5%3446%7%48%
1980
11th to 20thNight
19%9%36%5%3445%6%38%
2146
21st to endNight
21%9%36%5%34446%36%
2574
November1st to 10thNight
13%7%35%43446%6%44%
2406
11th to 20thNight
17%11%47%5%35%5%5%8%32%
2470
21st to endNight
19%11%5%7%6%345%5%6%28%
2470
December1st to 10thNight
17%14%6%8%7%46%5%46%23%
2470
11th to 20thNight
17%13%6%9%6%35%446%24%
3261
21st to endNight
26%18%7%9%6%34445%13%
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
65%6%10%14%5%
1510
11th to 20thDay
69%5%13%9%5%
1440
21st to endDay
69%5%8%12%5%1
1671
February1st to 10thDay
66%5%9%12%7%1
1690
11th to 20thDay
63%5%9%16%7%1
1758
21st to endDay
60%5%12%15%6%1
1480
March1st to 10thDay
56%6%11%20%7%
1800
11th to 20thDay
53%5%12%19%10%2
1953
21st to endDay
61%5%10%18%5%1
2205
April1st to 10thDay
53%6%10%19%11%
2160
11th to 20thDay
50%6%9%21%12%2
2187
21st to endDay
49%6%13%17%12%3
2340
May1st to 10thDay
52%7%12%19%10%
2340
11th to 20thDay
49%7%11%19%13%1
2305
21st to endDay
40%9%13%23%13%2
2587
June1st to 10thDay
40%7%10%25%16%2
2520
11th to 20thDay
36%7%12%25%18%2
2520
21st to endDay
39%9%13%21%15%3
2520
July1st to 10thDay
35%7%13%23%18%4
2451
11th to 20thDay
33%8%14%27%16%2
2445
21st to endDay
34%8%14%24%18%2
2510
August1st to 10thDay
32%9%16%26%15%1
2314
11th to 20thDay
36%8%14%25%14%2
2303
21st to endDay
33%8%13%23%18%4
2408
September1st to 10thDay
39%8%14%20%16%3
2095
11th to 20thDay
33%7%13%28%19%1
1980
21st to endDay
39%5%12%25%18%1
1980
October1st to 10thDay
41%6%11%25%15%2
1980
11th to 20thDay
45%6%11%21%16%
1810
21st to endDay
54%6%14%16%9%1
1782
November1st to 10thDay
38%6%12%26%17%1
1672
11th to 20thDay
54%5%11%18%10%1
1710
21st to endDay
60%5%11%16%7%
1710
December1st to 10thDay
66%5%12%12%5%
1710
11th to 20thDay
61%7%13%15%3
1930
21st to endDay
78%47%6%5%
2783
January1st to 10thNight
61%5%10%15%8%
2647
11th to 20thNight
63%7%12%13%5%
2520
21st to endNight
64%5%11%14%6%1
2682
February1st to 10thNight
63%5%11%13%6%1
2268
11th to 20thNight
57%5%9%19%9%1
2099
21st to endNight
58%411%16%10%1
1776
March1st to 10thNight
53%5%11%19%12%1
2160
11th to 20thNight
43%5%12%22%14%3
2007
21st to endNight
52%5%9%23%10%1
2165
April1st to 10thNight
44%7%11%22%15%1
1800
11th to 20thNight
47%6%9%17%18%2
1721
21st to endNight
47%6%10%20%14%3
1620
May1st to 10thNight
52%7%10%18%11%2
1620
11th to 20thNight
47%5%10%20%16%2
1593
21st to endNight
35%8%17%22%14%3
1685
June1st to 10thNight
31%7%13%27%19%3
1440
11th to 20thNight
35%7%12%24%19%3
1440
21st to endNight
35%8%16%23%15%3
1440
July1st to 10thNight
31%7%13%23%22%4
1400
11th to 20thNight
27%7%16%26%21%3
1392
21st to endNight
27%8%15%27%19%5%
1566
August1st to 10thNight
29%7%15%29%19%2
1600
11th to 20thNight
30%8%15%26%19%3
1598
21st to endNight
30%7%12%26%21%4
1944
September1st to 10thNight
34%8%12%22%19%5%
1846
11th to 20thNight
30%5%9%31%24%1
1980
21st to endNight
35%6%11%27%19%2
1980
October1st to 10thNight
35%6%11%28%19%1
1980
11th to 20thNight
47%5%9%22%15%1
2146
21st to endNight
49%5%11%22%12%1
2574
November1st to 10thNight
40%5%11%26%17%1
2406
11th to 20thNight
51%5%12%20%11%2
2470
21st to endNight
56%6%12%18%7%
2470
December1st to 10thNight
61%6%11%15%7%
2470
11th to 20thNight
61%5%13%13%7%1
3263
21st to endNight
73%6%10%8%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
22%18%35%19%5%1
267
11th to 20thDay
28%10%43%14%5%1
240
21st to endDay
25%16%33%20%6%
264
February1st to 10thDay
27%16%37%18%3
240
11th to 20thDay
24%19%37%15%5%
240
21st to endDay
25%21%42%10%2
198
March1st to 10thDay
22%19%38%17%4
240
11th to 20thDay
24%12%33%23%7%1
393
21st to endDay
30%13%31%19%6%1
462
April1st to 10thDay
20%15%32%21%10%2
420
11th to 20thDay
22%13%33%18%11%2
412
21st to endDay
23%15%30%18%12%3
420
May1st to 10thDay
24%11%31%21%10%3
423
11th to 20thDay
22%8%27%24%14%5%
447
21st to endDay
13%7%26%25%18%11%
541
June1st to 10thDay
12%7%28%31%17%5%
630
11th to 20thDay
11%6%32%24%20%6%
630
21st to endDay
13%6%27%31%17%7%
630
July1st to 10thDay
10%318%31%23%16%
621
11th to 20thDay
9%324%31%23%11%
618
21st to endDay
9%322%28%26%12%
599
August1st to 10thDay
8%215%30%26%19%
446
11th to 20thDay
9%420%27%27%13%
439
21st to endDay
10%218%25%29%16%
495
September1st to 10thDay
13%6%18%25%26%13%
450
11th to 20thDay
10%314%26%31%16%
450
21st to endDay
16%9%19%25%23%8%
450
October1st to 10thDay
14%7%25%29%16%9%
450
11th to 20thDay
19%15%28%30%7%1
426
21st to endDay
28%14%36%19%31
297
November1st to 10thDay
14%13%32%24%14%3
270
11th to 20thDay
26%16%30%18%10%
270
21st to endDay
27%13%37%18%4
270
December1st to 10thDay
21%23%32%16%9%
270
11th to 20thDay
22%15%40%18%5%
270
21st to endDay
24%22%35%16%2
297
January1st to 10thNight
22%15%36%21%6%
950
11th to 20thNight
25%11%36%22%5%1
900
21st to endNight
21%13%37%24%4
900
February1st to 10thNight
26%12%37%22%3
720
11th to 20thNight
21%14%37%26%3
703
21st to endNight
28%14%35%19%3
592
March1st to 10thNight
20%12%36%25%7%1
720
11th to 20thNight
18%12%37%28%6%1
720
21st to endNight
24%10%32%26%8%
779
April1st to 10thNight
18%12%35%27%7%1
540
11th to 20thNight
20%9%34%28%8%1
533
21st to endNight
20%8%34%26%10%1
540
May1st to 10thNight
19%8%34%30%8%1
540
11th to 20thNight
23%427%31%15%
531
21st to endNight
12%424%38%20%2
584
June1st to 10thNight
10%326%45%15%1
540
11th to 20thNight
11%325%40%20%
540
21st to endNight
9%426%36%24%2
540
July1st to 10thNight
9%316%40%28%4
525
11th to 20thNight
9%218%39%29%3
522
21st to endNight
7%117%42%33%1
591
August1st to 10thNight
6%215%45%27%5%
537
11th to 20thNight
8%112%43%31%4
534
21st to endNight
10%116%32%37%3
594
September1st to 10thNight
13%316%34%31%3
586
11th to 20thNight
12%414%34%33%3
720
21st to endNight
15%5%22%34%20%4
720
October1st to 10thNight
14%5%24%33%20%3
720
11th to 20thNight
21%14%27%28%10%1
720
21st to endNight
25%13%32%24%7%
792
November1st to 10thNight
16%11%32%27%12%1
740
11th to 20thNight
23%14%31%25%6%1
760
21st to endNight
24%12%31%27%6%
760
December1st to 10thNight
26%14%34%21%5%
760
11th to 20thNight
26%11%36%23%4
932
21st to endNight
30%14%31%23%3
1045
Page generated at 2024-01-07 10:06:52. Version ac07

Copyright 2024 Attilla Danko


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