Salmonberry
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Salmonberry clear sky chart from 2005-11-06 to 2024-01-17.

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
37%
22575
11%
74364
10%
22528
40%
22528
15%
54627

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
20%
760
6%
2646
5%
756
23%
756
7%
2254
January11th to 20thNight
27%
748
7%
2616
7%
748
29%
748
8%
2133
January21st to endNight
30%
792
12%
2600
11%
792
32%
792
11%
2050
February1st to 10thNight
23%
720
6%
2340
5%
720
24%
720
7%
1979
February11th to 20thNight
26%
700
8%
2274
5%
700
31%
700
9%
1838
February21st to endNight
23%
592
8%
1884
5%
592
27%
592
8%
1559
March1st to 10thNight
28%
720
7%
2042
6%
720
29%
720
11%
1676
March11th to 20thNight
26%
720
9%
1980
6%
720
28%
720
11%
1620
March21st to endNight
23%
792
5%
2156
3%
792
24%
792
8%
1878
April1st to 10thNight
25%
720
5%
1800
3%
720
27%
720
11%
1512
April11th to 20thNight
29%
671
9%
1739
5%
671
31%
671
15%
1378
April21st to endNight
35%
540
9%
1620
6%
540
37%
540
14%
1236
May1st to 10thNight
40%
424
12%
1504
11%
424
45%
424
17%
1013
May11th to 20thNight
48%
354
11%
1416
13%
354
51%
354
15%
959
May21st to endNight
40%
389
8%
1552
11%
388
43%
388
13%
1115
June1st to 10thNight
43%
360
7%
1440
10%
360
46%
360
15%
971
June11th to 20thNight
43%
360
8%
1308
9%
360
46%
360
17%
898
June21st to endNight
57%
360
16%
1260
17%
360
63%
360
32%
699
July1st to 10thNight
64%
350
15%
1233
18%
350
67%
350
35%
647
July11th to 20thNight
59%
348
21%
1392
28%
348
67%
348
37%
648
July21st to endNight
74%
394
26%
1488
37%
372
80%
372
56%
557
August1st to 10thNight
72%
537
21%
1602
19%
534
75%
534
49%
786
August11th to 20thNight
74%
534
28%
1602
24%
534
76%
534
49%
799
August21st to endNight
60%
685
26%
1873
17%
685
62%
685
40%
1080
September1st to 10thNight
64%
720
25%
1800
15%
720
66%
720
46%
1051
September11th to 20thNight
58%
720
20%
1831
13%
720
59%
720
31%
1213
September21st to endNight
52%
720
21%
2045
17%
720
55%
720
30%
1298
October1st to 10thNight
49%
720
15%
2160
14%
720
51%
720
26%
1402
October11th to 20thNight
45%
720
17%
2160
19%
720
48%
720
22%
1511
October21st to endNight
35%
792
16%
2394
13%
792
40%
792
17%
1735
November1st to 10thNight
28%
740
9%
2548
9%
740
30%
740
9%
2048
November11th to 20thNight
23%
760
7%
2660
5%
760
28%
760
8%
2187
November21st to endNight
29%
760
7%
2660
6%
760
32%
760
11%
2072
December1st to 10thNight
28%
760
9%
2660
8%
760
31%
760
10%
2094
December11th to 20thNight
22%
759
7%
3236
4%
759
24%
759
5%
2695
December21st to endNight
15%
834
3%
4843
4%
817
17%
817
3%
4036

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
20%13%47%6%34445%28%
75236
Night
18%13%5%8%6%34445%28%
74604
TransparencyDay
55%8%11%15%10%2
74935
Night
53%8%12%15%9%3
74423
SeeingDay
25%15%25%23%10%2
14001
Night
25%12%19%27%16%2
22582

By Month

Percentage Cloud Cover NW (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
32%22%5%9%6%3433311%
1519
11th to 20thDay
28%19%47%5%33335%20%
1488
21st to endDay
24%19%5%8%6%34335%22%
1755
February1st to 10thDay
27%20%6%9%7%44245%13%
1620
11th to 20thDay
23%24%6%10%7%3323316%
1575
21st to endDay
24%25%6%10%6%3333414%
1371
March1st to 10thDay
25%21%5%10%7%3443314%
1916
11th to 20thDay
28%22%6%6%6%3433415%
1980
21st to endDay
30%21%6%11%7%344239%
2200
April1st to 10thDay
26%21%6%9%6%34345%12%
2160
11th to 20thDay
28%17%5%8%7%3332418%
2169
21st to endDay
25%17%5%8%7%45%5%4418%
2340
May1st to 10thDay
20%13%48%6%35%5%45%28%
2456
11th to 20thDay
21%12%5%8%7%45%5%46%23%
2477
21st to endDay
25%11%5%8%7%45%5%5%5%21%
2723
June1st to 10thDay
26%11%47%6%35%445%25%
2520
11th to 20thDay
22%12%5%9%8%46%5%6%5%18%
2646
21st to endDay
14%7%36%5%35%5%5%7%39%
2700
July1st to 10thDay
9%8%25%5%35%5%47%47%
2688
11th to 20thDay
10%7%3442345%7%51%
2520
21st to endDay
7%5%2432345%7%60%
2738
August1st to 10thDay
6%6%3443436%8%53%
2328
11th to 20thDay
8%4244235%6%7%55%
2298
21st to endDay
9%7%36%5%445%5%7%44%
2481
September1st to 10thDay
7%6%36%433447%52%
2160
11th to 20thDay
13%8%36%6%35%5%6%6%39%
2126
21st to endDay
17%9%37%5%34435%40%
1914
October1st to 10thDay
21%10%36%5%33445%35%
1800
11th to 20thDay
21%8%49%7%3445%6%30%
1800
21st to endDay
26%12%37%6%24445%28%
1962
November1st to 10thDay
30%14%49%8%35%435%15%
1527
11th to 20thDay
30%15%6%8%5%3444417%
1520
21st to endDay
26%16%5%8%6%3443321%
1520
December1st to 10thDay
23%15%49%7%4434423%
1520
11th to 20thDay
25%16%5%9%8%45%5%4416%
1925
21st to endDay
24%22%7%10%7%4443413%
2794
January1st to 10thNight
30%17%5%10%7%3343414%
2646
11th to 20thNight
25%18%6%8%5%35%44417%
2616
21st to endNight
22%16%5%9%6%43445%21%
2600
February1st to 10thNight
21%19%7%11%8%45%34415%
2340
11th to 20thNight
19%21%5%11%6%45%33321%
2272
21st to endNight
19%23%6%11%6%4334318%
1884
March1st to 10thNight
21%17%6%9%8%34445%19%
2042
11th to 20thNight
21%19%6%10%6%3444419%
1979
21st to endNight
24%21%8%9%6%45%44313%
2156
April1st to 10thNight
21%19%7%10%7%4434417%
1800
11th to 20thNight
18%16%6%9%8%445%47%20%
1739
21st to endNight
19%13%49%7%45%5%6%7%23%
1620
May1st to 10thNight
13%14%5%9%6%34447%32%
1504
11th to 20thNight
16%10%38%7%36%6%6%8%26%
1416
21st to endNight
16%11%48%8%46%5%6%7%25%
1552
June1st to 10thNight
17%9%49%6%46%446%31%
1440
11th to 20thNight
14%12%47%7%45%5%6%9%26%
1308
21st to endNight
8%6%36%435%45%9%46%
1260
July1st to 10thNight
36%36%6%345%6%8%50%
1268
11th to 20thNight
6%5%345%345%5%8%54%
1440
21st to endNight
331332336%8%64%
1576
August1st to 10thNight
3424435%46%10%57%
1611
11th to 20thNight
5%41332445%7%61%
1602
21st to endNight
6%7%35%5%35%5%6%9%48%
1873
September1st to 10thNight
5%5%2443435%7%58%
1800
11th to 20thNight
9%6%36%6%346%6%6%44%
1831
21st to endNight
12%7%26%6%35%45%7%43%
2045
October1st to 10thNight
15%8%36%6%345%45%41%
2160
11th to 20thNight
18%10%37%6%34446%35%
2160
21st to endNight
21%12%36%6%34446%31%
2394
November1st to 10thNight
27%13%410%7%34345%19%
2548
11th to 20thNight
27%15%5%9%7%3434419%
2660
21st to endNight
21%14%5%9%7%45%43424%
2660
December1st to 10thNight
21%14%6%8%7%36%44422%
2660
11th to 20thNight
25%17%5%10%8%4444416%
3280
21st to endNight
24%19%6%11%8%4443314%
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
80%5%5%5%41
1519
11th to 20thDay
66%6%9%8%6%5%
1488
21st to endDay
66%6%7%11%9%1
1755
February1st to 10thDay
74%5%9%8%3
1620
11th to 20thDay
72%7%7%9%5%1
1584
21st to endDay
73%7%8%5%6%1
1371
March1st to 10thDay
72%7%8%8%5%
1916
11th to 20thDay
72%5%8%11%31
1980
21st to endDay
80%7%7%6%
2200
April1st to 10thDay
71%8%10%9%2
2160
11th to 20thDay
69%6%7%10%6%1
2169
21st to endDay
66%7%10%11%6%1
2340
May1st to 10thDay
53%8%15%17%6%
2456
11th to 20thDay
57%9%13%14%6%1
2480
21st to endDay
59%10%13%15%2
2724
June1st to 10thDay
58%7%15%13%7%
2520
11th to 20thDay
60%11%14%11%4
2646
21st to endDay
38%10%16%23%9%3
2700
July1st to 10thDay
34%7%13%22%19%4
2614
11th to 20thDay
28%6%12%27%21%5%
2445
21st to endDay
18%5%13%31%27%5%
2586
August1st to 10thDay
25%8%18%26%19%4
2312
11th to 20thDay
25%8%16%26%20%7%
2298
21st to endDay
34%8%12%27%16%3
2481
September1st to 10thDay
28%7%14%24%18%9%
2160
11th to 20thDay
41%10%12%17%15%5%
2126
21st to endDay
45%7%11%16%16%5%
1914
October1st to 10thDay
50%6%9%19%14%3
1800
11th to 20thDay
52%9%10%15%13%1
1800
21st to endDay
59%6%7%14%13%1
1962
November1st to 10thDay
70%7%9%10%31
1527
11th to 20thDay
69%6%9%8%6%2
1520
21st to endDay
66%7%6%8%13%1
1520
December1st to 10thDay
66%8%6%10%11%1
1520
11th to 20thDay
69%8%11%9%3
1928
21st to endDay
74%9%10%43
2794
January1st to 10thNight
72%7%7%7%5%2
2646
11th to 20thNight
67%7%9%8%5%4
2616
21st to endNight
64%5%7%11%10%2
2600
February1st to 10thNight
69%9%7%11%41
2340
11th to 20thNight
64%8%10%10%6%2
2274
21st to endNight
68%7%9%10%6%1
1884
March1st to 10thNight
65%8%11%11%5%
2042
11th to 20thNight
64%8%10%12%5%1
1980
21st to endNight
70%9%10%9%1
2156
April1st to 10thNight
66%7%12%10%4
1800
11th to 20thNight
59%8%13%12%7%2
1739
21st to endNight
54%10%14%14%7%1
1620
May1st to 10thNight
46%9%16%20%9%1
1504
11th to 20thNight
46%11%17%18%6%2
1416
21st to endNight
48%14%16%18%5%
1552
June1st to 10thNight
47%9%17%19%6%1
1440
11th to 20thNight
44%12%21%19%3
1308
21st to endNight
29%8%22%28%9%4
1260
July1st to 10thNight
22%11%17%25%18%7%
1233
11th to 20thNight
21%8%15%27%24%6%
1392
21st to endNight
11%5%16%33%23%12%
1488
August1st to 10thNight
16%8%22%26%22%6%
1602
11th to 20thNight
17%8%17%31%18%9%
1602
21st to endNight
25%8%16%29%18%4
1873
September1st to 10thNight
22%9%13%26%20%11%
1800
11th to 20thNight
35%11%13%18%15%8%
1831
21st to endNight
35%9%14%17%19%7%
2045
October1st to 10thNight
40%7%11%23%17%3
2160
11th to 20thNight
47%7%12%16%15%3
2160
21st to endNight
51%8%9%15%14%2
2394
November1st to 10thNight
64%8%10%12%6%1
2548
11th to 20thNight
67%8%9%8%6%2
2660
21st to endNight
61%8%8%8%13%2
2660
December1st to 10thNight
62%8%8%11%10%1
2660
11th to 20thNight
68%8%8%8%6%
3276
21st to endNight
71%9%10%8%2
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
43%22%18%11%6%1
180
11th to 20thDay
37%20%22%10%9%3
172
21st to endDay
37%15%17%22%9%1
347
February1st to 10thDay
42%18%16%16%7%1
340
11th to 20thDay
41%21%21%13%3
335
21st to endDay
38%23%21%12%4
298
March1st to 10thDay
37%20%26%12%5%
420
11th to 20thDay
34%20%23%15%7%1
420
21st to endDay
41%19%19%15%6%1
462
April1st to 10thDay
40%18%19%14%7%1
420
11th to 20thDay
37%19%21%14%8%2
412
21st to endDay
32%21%24%15%6%1
420
May1st to 10thDay
21%21%27%20%9%2
423
11th to 20thDay
30%13%26%19%10%2
448
21st to endDay
22%15%27%24%9%2
485
June1st to 10thDay
25%14%26%22%12%1
450
11th to 20thDay
23%22%31%18%5%1
576
21st to endDay
12%12%33%31%11%2
630
July1st to 10thDay
11%8%33%36%9%2
609
11th to 20thDay
9%12%31%33%13%2
444
21st to endDay
6%6%27%40%18%4
487
August1st to 10thDay
9%7%25%37%16%6%
447
11th to 20thDay
6%5%25%38%20%6%
437
21st to endDay
8%11%33%31%15%3
495
September1st to 10thDay
9%10%30%34%14%2
450
11th to 20thDay
15%12%26%28%14%4
450
21st to endDay
21%15%22%26%13%2
450
October1st to 10thDay
23%13%24%23%15%2
450
11th to 20thDay
27%14%20%22%15%3
450
21st to endDay
32%17%23%16%9%3
477
November1st to 10thDay
38%21%20%15%6%1
199
11th to 20thDay
32%21%23%13%8%3
180
21st to endDay
31%17%21%22%7%2
180
December1st to 10thDay
32%17%28%13%7%3
180
11th to 20thDay
37%22%21%14%6%
180
21st to endDay
40%18%20%17%6%
198
January1st to 10thNight
41%16%16%14%11%2
760
11th to 20thNight
35%14%17%18%14%2
748
21st to endNight
30%11%19%26%12%2
792
February1st to 10thNight
32%16%19%21%12%1
720
11th to 20thNight
31%15%18%23%12%1
704
21st to endNight
32%18%18%25%7%
592
March1st to 10thNight
29%18%19%21%12%1
720
11th to 20thNight
31%16%18%24%10%
720
21st to endNight
34%17%16%22%10%2
792
April1st to 10thNight
32%14%19%22%12%2
720
11th to 20thNight
26%14%23%25%11%1
671
21st to endNight
25%13%18%30%14%1
540
May1st to 10thNight
17%14%21%31%15%1
424
11th to 20thNight
19%8%14%34%23%2
354
21st to endNight
19%9%20%32%19%1
389
June1st to 10thNight
19%7%20%36%17%1
360
11th to 20thNight
17%11%23%34%15%1
360
21st to endNight
11%7%19%40%22%1
360
July1st to 10thNight
5%420%41%29%1
350
11th to 20thNight
5%5%24%44%21%1
348
21st to endNight
3216%45%31%2
394
August1st to 10thNight
4414%37%35%5%
537
11th to 20thNight
7%111%39%37%5%
534
21st to endNight
9%6%19%37%26%2
685
September1st to 10thNight
7%420%39%28%2
720
11th to 20thNight
10%5%18%32%29%6%
720
21st to endNight
15%8%18%35%21%3
720
October1st to 10thNight
19%7%20%31%21%3
720
11th to 20thNight
22%9%16%27%21%4
720
21st to endNight
28%11%19%22%16%3
792
November1st to 10thNight
32%13%19%24%11%1
740
11th to 20thNight
35%14%20%20%10%1
760
21st to endNight
26%16%21%24%11%2
760
December1st to 10thNight
28%12%24%23%12%2
760
11th to 20thNight
38%15%19%18%9%1
760
21st to endNight
43%17%19%13%7%1
836
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