Stayton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Stayton clear sky chart from 2005-11-06 to 2024-03-08.

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
42%
22867
12%
80775
12%
22771
46%
22771
16%
58830

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
26%
755
3%
4406
5%
736
28%
736
4%
3945
January11th to 20thNight
32%
757
8%
4407
9%
740
35%
740
5%
3723
January21st to endNight
35%
835
7%
4535
13%
814
37%
814
6%
3840
February1st to 10thNight
32%
760
6%
2470
7%
760
33%
760
10%
2036
February11th to 20thNight
30%
740
9%
2404
7%
740
33%
740
11%
1897
February21st to endNight
29%
628
11%
1958
9%
628
33%
628
10%
1573
March1st to 10thNight
30%
750
8%
2148
6%
750
33%
750
12%
1735
March11th to 20thNight
33%
720
10%
1980
8%
720
35%
720
15%
1560
March21st to endNight
29%
792
5%
2138
3%
792
29%
792
10%
1820
April1st to 10thNight
31%
720
8%
1800
4%
720
33%
720
13%
1496
April11th to 20thNight
36%
711
9%
1779
4%
711
38%
711
17%
1401
April21st to endNight
38%
558
10%
1638
6%
558
41%
558
16%
1228
May1st to 10thNight
39%
423
13%
1503
10%
423
46%
423
19%
1001
May11th to 20thNight
48%
354
12%
1416
13%
354
51%
354
15%
953
May21st to endNight
42%
389
8%
1552
9%
388
47%
388
13%
1088
June1st to 10thNight
41%
360
8%
1440
9%
360
46%
360
17%
941
June11th to 20thNight
42%
360
9%
1440
12%
360
47%
360
17%
941
June21st to endNight
54%
360
17%
1440
20%
360
64%
360
32%
723
July1st to 10thNight
68%
350
18%
1400
25%
350
75%
350
42%
605
July11th to 20thNight
58%
348
27%
1392
27%
348
75%
348
46%
576
July21st to endNight
75%
398
34%
1492
40%
376
87%
376
72%
474
August1st to 10thNight
74%
537
27%
1602
21%
534
81%
534
59%
720
August11th to 20thNight
76%
534
32%
1602
24%
534
80%
534
56%
749
August21st to endNight
63%
727
34%
1915
18%
727
70%
727
55%
1003
September1st to 10thNight
63%
720
31%
1800
16%
720
67%
720
54%
976
September11th to 20thNight
63%
720
26%
1800
17%
720
66%
720
39%
1122
September21st to endNight
59%
720
25%
2063
22%
720
62%
720
34%
1248
October1st to 10thNight
51%
720
16%
2160
14%
720
54%
720
27%
1396
October11th to 20thNight
54%
720
19%
2160
20%
720
56%
720
24%
1449
October21st to endNight
40%
792
17%
2399
14%
792
44%
792
18%
1724
November1st to 10thNight
35%
740
11%
2485
12%
740
36%
740
11%
1945
November11th to 20thNight
32%
760
8%
2660
8%
760
34%
760
9%
2142
November21st to endNight
40%
760
8%
2660
7%
760
42%
760
13%
1992
December1st to 10thNight
39%
760
10%
2660
10%
760
40%
760
12%
2019
December11th to 20thNight
31%
759
6%
3222
7%
759
32%
759
7%
2667
December21st to endNight
23%
830
3%
4849
6%
817
25%
817
3%
4122

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
23%8%35%5%24446%35%
78515
Night
26%9%36%5%34345%33%
81055
TransparencyDay
51%7%11%17%11%3
78219
Night
54%7%11%15%10%3
80872
SeeingDay
24%7%23%27%15%4
13738
Night
28%5%17%30%18%2
22887

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 10thDay
40%17%47%6%35%3439%
2539
11th to 20thDay
43%11%36%5%3332417%
2540
21st to endDay
38%12%36%435%445%15%
3096
February1st to 10thDay
33%11%46%5%24447%18%
1710
11th to 20thDay
31%12%37%6%34445%20%
1665
21st to endDay
32%15%37%5%23435%21%
1495
March1st to 10thDay
30%14%46%436%446%18%
1969
11th to 20thDay
33%10%36%6%35%346%21%
1980
21st to endDay
33%13%5%8%6%35%435%15%
2218
April1st to 10thDay
31%13%48%7%34445%16%
2160
11th to 20thDay
28%11%47%6%34445%25%
2129
21st to endDay
25%10%37%5%35%45%7%27%
2320
May1st to 10thDay
19%9%37%5%3445%6%35%
2456
11th to 20thDay
22%8%37%6%35%45%6%31%
2477
21st to endDay
26%7%36%5%3445%6%29%
2723
June1st to 10thDay
26%8%36%5%33445%34%
2520
11th to 20thDay
22%7%36%6%35%5%6%6%31%
2520
21st to endDay
11%5%14424336%57%
2520
July1st to 10thDay
6%313323346%65%
2520
11th to 20thDay
7%313213346%68%
2520
21st to endDay
5%31121222478%
2735
August1st to 10thDay
4213324347%68%
2328
11th to 20thDay
5%33312347%70%
2298
21st to endDay
5%314324447%62%
2440
September1st to 10thDay
8%313212346%68%
2160
11th to 20thDay
13%5%25%5%345%5%6%48%
2160
21st to endDay
17%5%24424446%47%
1891
October1st to 10thDay
20%7%2442446%5%43%
1800
11th to 20thDay
22%8%26%5%34446%37%
1800
21st to endDay
27%8%26%5%33445%32%
1955
November1st to 10thDay
35%10%46%5%2335%5%22%
1589
11th to 20thDay
36%9%26%6%35%45%6%20%
1520
21st to endDay
32%9%37%5%34445%24%
1520
December1st to 10thDay
28%10%37%5%2435%6%27%
1520
11th to 20thDay
34%11%36%6%36%7%7%7%11%
1928
21st to endDay
34%14%48%5%345%5%6%11%
2794
January1st to 10thNight
39%16%48%6%3443310%
4406
11th to 20thNight
41%13%37%5%2323417%
4420
21st to endNight
38%15%47%5%33335%16%
4552
February1st to 10thNight
31%12%47%6%33446%19%
2470
11th to 20thNight
33%11%36%42344426%
2402
21st to endNight
32%15%36%42345%5%21%
1958
March1st to 10thNight
28%14%37%6%3435%5%22%
2148
11th to 20thNight
29%10%47%5%3445%6%24%
1980
21st to endNight
31%14%47%5%35%435%18%
2138
April1st to 10thNight
30%13%37%6%3435%5%22%
1800
11th to 20thNight
27%11%45%435%446%27%
1779
21st to endNight
25%10%35%5%34446%31%
1638
May1st to 10thNight
18%8%37%425%346%39%
1503
11th to 20thNight
18%9%37%6%3445%8%34%
1416
21st to endNight
22%7%36%5%36%5%5%8%31%
1552
June1st to 10thNight
20%7%37%424446%38%
1440
11th to 20thNight
19%7%36%5%35%35%5%38%
1440
21st to endNight
9%5%25%42233361%
1440
July1st to 10thNight
7%41332333470%
1440
11th to 20thNight
5%323213335%72%
1440
21st to endNight
31111213483%
1580
August1st to 10thNight
3313212247%72%
1611
11th to 20thNight
431332223473%
1602
21st to endNight
7%213222235%70%
1915
September1st to 10thNight
8%313322235%69%
1800
11th to 20thNight
11%414435%5%5%6%54%
1800
21st to endNight
14%5%2443335%6%51%
2063
October1st to 10thNight
19%6%26%5%23345%46%
2160
11th to 20thNight
20%6%25%43335%6%42%
2160
21st to endNight
26%9%35%42333438%
2399
November1st to 10thNight
32%9%26%6%34345%25%
2485
11th to 20thNight
36%7%36%5%34445%22%
2660
21st to endNight
30%8%26%4345%45%29%
2660
December1st to 10thNight
30%8%45%5%34446%27%
2660
11th to 20thNight
33%12%37%5%3445%7%19%
3276
21st to endNight
30%13%48%8%45%445%15%
4862

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
79%9%6%411
2539
11th to 20thDay
73%6%7%8%33
2540
21st to endDay
69%9%8%8%5%1
3096
February1st to 10thDay
66%8%11%10%5%
1710
11th to 20thDay
67%9%9%8%42
1674
21st to endDay
69%7%8%9%5%2
1495
March1st to 10thDay
67%8%11%11%4
1969
11th to 20thDay
65%6%10%13%5%1
1980
21st to endDay
73%7%9%9%2
2218
April1st to 10thDay
71%7%9%10%4
2160
11th to 20thDay
62%7%11%11%6%2
2132
21st to endDay
58%7%14%12%8%2
2320
May1st to 10thDay
49%7%14%21%8%
2456
11th to 20thDay
53%8%14%18%6%1
2480
21st to endDay
54%9%16%18%3
2724
June1st to 10thDay
52%6%16%20%5%
2520
11th to 20thDay
51%8%19%16%5%
2520
21st to endDay
30%5%16%32%12%4
2520
July1st to 10thDay
20%6%15%28%25%6%
2451
11th to 20thDay
20%410%24%34%9%
2445
21st to endDay
12%38%30%38%9%
2583
August1st to 10thDay
18%5%14%34%22%6%
2312
11th to 20thDay
17%413%34%25%7%
2298
21st to endDay
21%6%11%31%26%4
2440
September1st to 10thDay
19%313%30%23%13%
2160
11th to 20thDay
36%7%11%22%16%7%
2160
21st to endDay
39%7%12%19%17%7%
1891
October1st to 10thDay
41%8%11%19%16%5%
1800
11th to 20thDay
50%8%12%14%14%3
1800
21st to endDay
54%9%9%13%13%2
1955
November1st to 10thDay
65%8%10%12%5%
1589
11th to 20thDay
65%8%10%8%6%3
1520
21st to endDay
62%8%9%7%13%1
1520
December1st to 10thDay
60%8%10%9%11%2
1520
11th to 20thDay
69%11%8%9%2
1928
21st to endDay
72%12%9%5%2
2794
January1st to 10thNight
78%8%6%431
4406
11th to 20thNight
74%6%5%10%32
4420
21st to endNight
73%5%6%8%6%1
4552
February1st to 10thNight
68%6%11%9%5%2
2470
11th to 20thNight
62%7%12%10%6%2
2404
21st to endNight
65%6%10%11%6%2
1958
March1st to 10thNight
64%6%11%13%6%
2148
11th to 20thNight
60%6%13%14%5%2
1980
21st to endNight
69%7%11%11%2
2138
April1st to 10thNight
65%7%11%12%5%
1800
11th to 20thNight
57%7%15%11%6%3
1779
21st to endNight
56%6%15%14%6%3
1638
May1st to 10thNight
47%6%13%23%9%2
1503
11th to 20thNight
50%7%17%18%44
1416
21st to endNight
52%9%17%18%5%
1552
June1st to 10thNight
46%8%17%25%4
1440
11th to 20thNight
46%7%20%20%7%
1440
21st to endNight
29%5%17%32%13%5%
1440
July1st to 10thNight
21%414%28%25%9%
1400
11th to 20thNight
18%411%23%34%10%
1392
21st to endNight
7%29%33%38%12%
1492
August1st to 10thNight
14%415%39%21%7%
1602
11th to 20thNight
17%313%36%24%7%
1602
21st to endNight
18%5%10%37%23%6%
1915
September1st to 10thNight
20%411%30%22%12%
1800
11th to 20thNight
31%7%13%25%14%10%
1800
21st to endNight
33%6%13%22%16%10%
2063
October1st to 10thNight
41%6%8%22%17%5%
2160
11th to 20thNight
43%7%11%17%17%4
2160
21st to endNight
51%7%9%13%17%4
2399
November1st to 10thNight
61%8%10%13%8%1
2485
11th to 20thNight
64%8%9%8%9%2
2660
21st to endNight
57%8%9%11%11%4
2660
December1st to 10thNight
59%7%10%12%10%2
2660
11th to 20thNight
67%9%10%9%5%
3276
21st to endNight
68%14%10%6%21
4862

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
51%5%18%16%8%1
180
11th to 20thDay
42%7%20%18%8%4
180
21st to endDay
37%7%20%20%13%3
383
February1st to 10thDay
40%5%23%18%12%2
370
11th to 20thDay
38%9%25%19%7%2
365
21st to endDay
39%11%19%18%11%1
347
March1st to 10thDay
37%8%27%19%9%
449
11th to 20thDay
33%9%23%22%11%2
420
21st to endDay
35%11%27%16%10%1
462
April1st to 10thDay
38%11%20%20%9%3
420
11th to 20thDay
33%12%24%20%9%3
412
21st to endDay
32%9%27%18%12%2
420
May1st to 10thDay
19%13%29%25%12%3
423
11th to 20thDay
30%6%20%25%15%4
448
21st to endDay
22%6%23%28%17%4
485
June1st to 10thDay
24%6%23%32%14%2
450
11th to 20thDay
21%7%30%29%12%1
450
21st to endDay
9%6%23%41%16%5%
450
July1st to 10thDay
8%5%22%38%21%5%
446
11th to 20thDay
47%25%39%20%5%
444
21st to endDay
4319%47%22%5%
487
August1st to 10thDay
4219%39%28%6%
447
11th to 20thDay
3316%46%23%8%
437
21st to endDay
5%5%27%39%20%4
495
September1st to 10thDay
9%5%26%34%21%4
450
11th to 20thDay
15%7%20%32%21%5%
450
21st to endDay
19%8%24%29%16%4
450
October1st to 10thDay
20%6%24%25%19%5%
450
11th to 20thDay
24%6%17%25%23%4
450
21st to endDay
31%8%25%19%12%6%
470
November1st to 10thDay
36%11%22%17%12%3
230
11th to 20thDay
37%322%18%14%6%
180
21st to endDay
36%7%22%14%16%5%
180
December1st to 10thDay
39%9%17%19%11%6%
180
11th to 20thDay
49%8%18%15%7%3
180
21st to endDay
46%6%18%16%12%2
198
January1st to 10thNight
43%7%15%18%14%2
760
11th to 20thNight
41%6%13%23%15%2
760
21st to endNight
35%5%13%30%15%2
836
February1st to 10thNight
35%6%16%26%15%2
760
11th to 20thNight
39%5%17%24%14%1
744
21st to endNight
40%8%15%26%10%
628
March1st to 10thNight
35%7%18%27%12%1
750
11th to 20thNight
31%8%19%26%16%1
720
21st to endNight
36%6%20%24%13%2
792
April1st to 10thNight
34%5%17%26%16%1
720
11th to 20thNight
31%6%21%25%16%1
711
21st to endNight
28%5%21%30%16%1
558
May1st to 10thNight
20%428%32%14%2
423
11th to 20thNight
22%316%34%21%2
354
21st to endNight
24%319%33%20%1
389
June1st to 10thNight
21%422%36%16%1
360
11th to 20thNight
23%423%39%12%1
360
21st to endNight
9%227%41%20%
360
July1st to 10thNight
8%215%49%25%
350
11th to 20thNight
5%428%44%19%1
348
21st to endNight
3219%52%24%1
398
August1st to 10thNight
5%214%38%36%4
537
11th to 20thNight
5%310%45%36%3
534
21st to endNight
8%322%41%24%2
727
September1st to 10thNight
9%320%41%25%2
720
11th to 20thNight
13%313%33%32%6%
720
21st to endNight
16%316%37%25%3
720
October1st to 10thNight
20%318%33%23%3
720
11th to 20thNight
22%415%31%25%4
720
21st to endNight
30%5%19%25%16%4
792
November1st to 10thNight
36%6%14%29%14%1
740
11th to 20thNight
39%6%17%23%14%1
760
21st to endNight
29%7%15%29%18%2
760
December1st to 10thNight
34%5%13%30%15%2
760
11th to 20thNight
43%5%14%23%15%1
760
21st to endNight
45%7%17%19%10%1
836
Page generated at 2024-03-05 04:24:03. Version ac07

Copyright © 2024 Attilla Danko.


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