Abbotsford
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Abbotsford 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
37%
22499
9%
74720
8%
22443
39%
22443
13%
56398

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
18%
849
7%
2833
6%
845
21%
845
6%
2427
January11th to 20thNight
28%
777
6%
2649
6%
777
30%
777
9%
2152
January21st to endNight
26%
792
9%
2772
7%
792
30%
792
9%
2217
February1st to 10thNight
21%
720
8%
2340
3%
720
27%
720
8%
1932
February11th to 20thNight
22%
700
8%
2274
5%
700
28%
700
9%
1855
February21st to endNight
25%
592
13%
1883
7%
592
33%
592
11%
1470
March1st to 10thNight
31%
720
8%
2129
6%
720
33%
720
12%
1684
March11th to 20thNight
26%
720
9%
1980
5%
720
28%
720
12%
1626
March21st to endNight
27%
792
5%
2100
2%
792
29%
792
10%
1765
April1st to 10thNight
31%
720
6%
1800
3%
720
32%
720
13%
1496
April11th to 20thNight
32%
656
10%
1724
6%
656
34%
656
15%
1376
April21st to endNight
35%
464
7%
1544
6%
464
37%
464
11%
1201
May1st to 10thNight
47%
360
10%
1440
16%
360
49%
360
16%
967
May11th to 20thNight
56%
354
9%
1416
17%
354
57%
354
16%
949
May21st to endNight
53%
388
6%
1552
11%
388
54%
388
16%
1051
June1st to 10thNight
47%
360
3%
1267
3%
360
47%
360
15%
930
June11th to 20thNight
43%
360
2%
1260
1%
360
43%
360
12%
965
June21st to endNight
61%
360
7%
1260
4%
360
61%
360
24%
780
July1st to 10thNight
64%
350
8%
1225
8%
350
64%
350
27%
727
July11th to 20thNight
69%
348
15%
1219
19%
348
70%
348
33%
669
July21st to endNight
83%
394
18%
1488
31%
372
85%
372
44%
640
August1st to 10thNight
75%
358
17%
1424
26%
356
77%
356
35%
683
August11th to 20thNight
78%
521
22%
1589
23%
521
79%
521
45%
811
August21st to endNight
65%
677
19%
1865
15%
677
66%
677
32%
1159
September1st to 10thNight
66%
720
17%
1800
10%
720
67%
720
37%
1148
September11th to 20thNight
53%
720
18%
1800
11%
720
54%
720
27%
1261
September21st to endNight
50%
720
16%
2052
14%
720
51%
720
22%
1448
October1st to 10thNight
47%
720
10%
2160
10%
720
48%
720
19%
1543
October11th to 20thNight
37%
720
10%
2160
10%
720
39%
720
15%
1641
October21st to endNight
30%
792
10%
2511
8%
792
35%
792
12%
1920
November1st to 10thNight
22%
740
6%
2588
5%
740
25%
740
8%
2131
November11th to 20thNight
21%
760
8%
2660
5%
760
25%
760
8%
2161
November21st to endNight
22%
760
6%
2660
3%
760
26%
760
7%
2189
December1st to 10thNight
29%
760
11%
2660
7%
760
36%
760
11%
2057
December11th to 20thNight
14%
823
4%
3453
2%
822
16%
822
4%
2984
December21st to endNight
13%
932
4%
5183
4%
905
18%
905
3%
4383

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
26%9%36%5%34445%30%
74747
Night
29%10%36%5%34445%29%
74931
TransparencyDay
57%6%13%16%7%1
74439
Night
59%6%12%15%7%2
74757
SeeingDay
29%10%22%24%12%4
14081
Night
35%7%14%24%18%3
22507

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
44%12%36%5%2433315%
1322
11th to 20thDay
36%12%47%5%24435%19%
1309
21st to endDay
38%12%36%423445%20%
1584
February1st to 10thDay
36%11%47%6%35%34418%
1616
11th to 20thDay
33%12%36%5%33346%21%
1575
21st to endDay
26%16%5%7%7%3433421%
1372
March1st to 10thDay
31%14%48%6%3444419%
1828
11th to 20thDay
33%13%47%6%35%33418%
1980
21st to endDay
31%13%48%7%4444418%
2255
April1st to 10thDay
31%11%48%6%35%445%17%
2160
11th to 20thDay
25%11%5%8%7%46%445%20%
2183
21st to endDay
27%11%5%7%7%35%45%5%22%
2416
May1st to 10thDay
23%9%47%6%35%5%45%31%
2520
11th to 20thDay
19%9%36%6%46%45%8%29%
2477
21st to endDay
25%10%48%6%34345%28%
2723
June1st to 10thDay
27%8%47%6%3445%6%26%
2690
11th to 20thDay
29%10%48%6%45%446%21%
2700
21st to endDay
18%7%46%6%45%5%5%6%36%
2700
July1st to 10thDay
14%6%35%5%2445%5%48%
2700
11th to 20thDay
12%5%25%424446%50%
2696
21st to endDay
10%423323346%62%
2741
August1st to 10thDay
12%5%14333346%54%
2507
11th to 20thDay
9%5%2442445%6%56%
2307
21st to endDay
16%6%25%5%34448%43%
2490
September1st to 10thDay
15%8%25%5%23346%47%
2160
11th to 20thDay
18%7%47%6%4334439%
2160
21st to endDay
24%7%36%5%33345%36%
1904
October1st to 10thDay
25%10%35%5%2335%5%35%
1800
11th to 20thDay
31%9%36%5%3435%6%25%
1800
21st to endDay
36%8%36%5%2335%5%24%
1844
November1st to 10thDay
40%9%48%6%24345%17%
1488
11th to 20thDay
39%12%36%42323322%
1520
21st to endDay
38%12%46%323345%19%
1520
December1st to 10thDay
33%14%36%42233426%
1520
11th to 20thDay
36%13%47%5%2434418%
1738
21st to endDay
38%15%5%8%6%3433411%
2442
January1st to 10thNight
44%13%36%5%2233316%
2833
11th to 20thNight
41%11%34423335%21%
2649
21st to endNight
35%14%46%423235%22%
2772
February1st to 10thNight
39%10%37%5%3433420%
2340
11th to 20thNight
32%16%37%5%3433421%
2272
21st to endNight
30%13%45%5%2344425%
1883
March1st to 10thNight
30%11%37%435%45%5%23%
2129
11th to 20thNight
33%10%37%6%33445%21%
1979
21st to endNight
34%12%37%5%2444419%
2100
April1st to 10thNight
30%12%37%6%445%45%21%
1800
11th to 20thNight
26%9%47%7%46%445%25%
1724
21st to endNight
30%10%47%6%245%46%22%
1544
May1st to 10thNight
20%8%37%5%2445%6%36%
1440
11th to 20thNight
17%7%36%5%45%6%7%7%33%
1416
21st to endNight
21%7%46%5%3445%7%34%
1552
June1st to 10thNight
20%9%47%6%45%45%5%31%
1267
11th to 20thNight
22%10%47%6%36%5%6%6%24%
1260
21st to endNight
16%6%26%4345%5%7%43%
1260
July1st to 10thNight
13%5%25%6%2343452%
1260
11th to 20thNight
9%6%24432346%57%
1261
21st to endNight
6%212323346%66%
1576
August1st to 10thNight
10%41322335%6%60%
1432
11th to 20thNight
8%22232335%8%62%
1589
21st to endNight
11%6%25%5%35%46%9%45%
1865
September1st to 10thNight
12%424425%45%7%52%
1800
11th to 20thNight
19%6%25%5%33346%43%
1800
21st to endNight
21%8%36%5%23345%39%
2052
October1st to 10thNight
23%7%35%44445%5%36%
2160
11th to 20thNight
31%9%35%424345%30%
2160
21st to endNight
34%9%35%5%23435%27%
2511
November1st to 10thNight
41%10%46%43343418%
2588
11th to 20thNight
40%10%35%5%2333422%
2660
21st to endNight
40%9%36%435%33420%
2660
December1st to 10thNight
33%10%35%424445%26%
2660
11th to 20thNight
42%13%47%5%3333315%
3463
21st to endNight
41%14%47%5%3432414%
5214

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
76%5%6%8%41
1322
11th to 20thDay
70%7%8%10%32
1309
21st to endDay
66%6%9%14%41
1584
February1st to 10thDay
71%48%8%6%2
1616
11th to 20thDay
67%6%8%11%8%1
1584
21st to endDay
69%49%12%5%2
1372
March1st to 10thDay
69%5%10%11%41
1828
11th to 20thDay
71%5%7%12%5%1
1980
21st to endDay
72%5%10%11%2
2255
April1st to 10thDay
69%6%12%10%2
2160
11th to 20thDay
66%5%8%11%7%2
2183
21st to endDay
64%6%12%10%7%1
2416
May1st to 10thDay
56%6%15%16%7%1
2520
11th to 20thDay
53%8%17%16%7%
2480
21st to endDay
59%7%16%16%2
2724
June1st to 10thDay
60%5%15%13%5%2
2690
11th to 20thDay
66%5%15%10%3
2700
21st to endDay
49%7%16%18%8%1
2700
July1st to 10thDay
39%7%14%25%12%2
2626
11th to 20thDay
36%5%17%30%10%2
2615
21st to endDay
25%5%17%35%15%4
2589
August1st to 10thDay
32%6%19%30%11%2
2490
11th to 20thDay
29%6%20%29%14%2
2307
21st to endDay
40%6%19%27%7%1
2490
September1st to 10thDay
41%6%14%23%12%4
2160
11th to 20thDay
50%5%10%17%15%3
2160
21st to endDay
51%6%14%17%10%2
1904
October1st to 10thDay
53%5%14%17%11%1
1800
11th to 20thDay
61%5%12%16%41
1800
21st to endDay
63%5%10%12%8%1
1844
November1st to 10thDay
72%49%10%31
1488
11th to 20thDay
71%38%9%6%2
1520
21st to endDay
69%5%6%11%8%2
1520
December1st to 10thDay
66%5%8%11%10%1
1520
11th to 20thDay
70%6%8%11%31
1741
21st to endDay
74%10%7%7%21
2442
January1st to 10thNight
74%5%5%11%41
2833
11th to 20thNight
68%6%11%10%42
2649
21st to endNight
67%5%8%14%5%1
2772
February1st to 10thNight
71%49%9%5%2
2340
11th to 20thNight
69%48%11%6%2
2274
21st to endNight
64%49%15%6%2
1883
March1st to 10thNight
62%6%13%12%5%1
2129
11th to 20thNight
66%5%10%12%6%1
1980
21st to endNight
69%5%15%9%2
2100
April1st to 10thNight
66%6%13%13%2
1800
11th to 20thNight
61%6%11%14%7%2
1724
21st to endNight
64%5%12%12%6%1
1544
May1st to 10thNight
49%7%19%17%7%1
1440
11th to 20thNight
49%7%21%17%6%
1416
21st to endNight
50%7%19%19%5%
1552
June1st to 10thNight
56%6%17%13%5%2
1267
11th to 20thNight
59%8%18%12%3
1260
21st to endNight
40%6%23%20%7%3
1260
July1st to 10thNight
36%7%13%26%14%4
1225
11th to 20thNight
30%6%18%31%13%2
1219
21st to endNight
19%5%15%35%21%5%
1488
August1st to 10thNight
26%5%19%31%17%3
1424
11th to 20thNight
22%6%23%30%14%6%
1589
21st to endNight
37%5%19%29%10%1
1865
September1st to 10thNight
33%7%18%25%14%4
1800
11th to 20thNight
44%6%13%17%15%4
1800
21st to endNight
48%7%15%19%9%2
2052
October1st to 10thNight
51%6%14%19%9%1
2160
11th to 20thNight
59%5%14%15%6%1
2160
21st to endNight
60%6%11%14%9%
2511
November1st to 10thNight
70%5%10%11%31
2588
11th to 20thNight
69%5%10%8%6%2
2660
21st to endNight
70%5%8%8%8%2
2660
December1st to 10thNight
61%7%11%12%8%1
2660
11th to 20thNight
76%6%7%6%31
3459
21st to endNight
74%6%8%7%4
5214

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
46%12%20%10%9%4
178
11th to 20thDay
49%10%13%16%9%3
160
21st to endDay
41%10%16%20%11%1
176
February1st to 10thDay
48%13%18%14%5%1
336
11th to 20thDay
42%10%23%17%7%1
335
21st to endDay
40%11%26%15%7%1
298
March1st to 10thDay
39%13%23%18%6%1
420
11th to 20thDay
39%12%17%20%10%2
420
21st to endDay
40%13%20%18%8%1
462
April1st to 10thDay
38%12%21%19%9%2
420
11th to 20thDay
28%15%25%18%11%3
412
21st to endDay
29%16%25%18%10%2
420
May1st to 10thDay
24%10%30%26%9%2
423
11th to 20thDay
26%7%21%25%15%6%
448
21st to endDay
29%9%23%24%11%5%
485
June1st to 10thDay
25%11%27%24%10%2
620
11th to 20thDay
29%11%26%25%7%2
630
21st to endDay
20%9%25%27%16%3
630
July1st to 10thDay
18%6%26%33%14%3
621
11th to 20thDay
12%9%26%35%15%4
614
21st to endDay
10%6%19%39%19%7%
487
August1st to 10thDay
15%5%19%32%19%10%
447
11th to 20thDay
9%5%18%36%23%9%
437
21st to endDay
17%9%22%30%15%6%
495
September1st to 10thDay
21%9%22%30%14%5%
450
11th to 20thDay
22%9%18%31%17%4
450
21st to endDay
28%7%20%25%14%5%
450
October1st to 10thDay
32%8%18%19%18%5%
450
11th to 20thDay
37%9%14%20%16%4
450
21st to endDay
40%12%18%18%11%3
359
November1st to 10thDay
40%16%19%16%9%
180
11th to 20thDay
52%415%10%12%7%
180
21st to endDay
46%7%22%8%12%6%
180
December1st to 10thDay
47%9%17%11%11%6%
180
11th to 20thDay
48%12%16%15%8%1
180
21st to endDay
49%9%19%18%5%1
198
January1st to 10thNight
51%11%14%14%9%1
849
11th to 20thNight
47%7%13%21%12%1
777
21st to endNight
43%8%16%22%10%1
792
February1st to 10thNight
45%10%18%21%6%1
720
11th to 20thNight
42%8%19%22%9%
704
21st to endNight
36%10%20%22%10%1
592
March1st to 10thNight
33%11%18%23%14%1
720
11th to 20thNight
42%7%18%21%11%1
720
21st to endNight
40%8%16%24%10%2
792
April1st to 10thNight
38%7%16%26%12%1
720
11th to 20thNight
30%8%19%25%16%2
656
21st to endNight
37%6%13%29%14%2
464
May1st to 10thNight
24%6%13%32%23%2
360
11th to 20thNight
21%39%29%34%4
354
21st to endNight
26%48%31%28%3
389
June1st to 10thNight
24%5%14%29%23%4
360
11th to 20thNight
26%5%15%29%21%4
360
21st to endNight
19%39%30%33%5%
360
July1st to 10thNight
15%210%28%42%3
350
11th to 20thNight
12%5%7%30%39%8%
348
21st to endNight
8%15%27%52%8%
394
August1st to 10thNight
15%1422%44%15%
358
11th to 20thNight
8%16%24%48%12%
521
21st to endNight
14%37%31%39%5%
677
September1st to 10thNight
16%29%39%28%6%
720
11th to 20thNight
22%5%11%23%33%7%
720
21st to endNight
27%5%12%28%25%3
720
October1st to 10thNight
27%413%26%25%4
720
11th to 20thNight
37%7%13%23%17%3
720
21st to endNight
40%8%17%23%10%2
792
November1st to 10thNight
48%8%17%21%5%
740
11th to 20thNight
48%7%17%16%10%1
760
21st to endNight
47%9%16%16%11%2
760
December1st to 10thNight
38%8%19%24%11%1
760
11th to 20thNight
50%10%19%17%31
823
21st to endNight
52%9%20%15%4
935
Page generated at 2024-01-07 07:06:56. Version ac07

Copyright 2024 Attilla Danko


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