Tofino
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tofino clear sky chart from 2005-11-06 to 2024-01-12.

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%
22760
9%
74862
8%
22703
38%
22703
12%
58212

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%
850
8%
2836
6%
846
21%
846
6%
2432
January11th to 20thNight
22%
805
6%
2715
5%
805
23%
805
6%
2280
January21st to endNight
29%
874
7%
2799
5%
874
31%
874
9%
2332
February1st to 10thNight
23%
720
8%
2340
6%
720
28%
720
8%
1971
February11th to 20thNight
30%
700
10%
2274
8%
700
34%
700
12%
1763
February21st to endNight
27%
592
11%
1911
9%
592
31%
592
11%
1498
March1st to 10thNight
30%
720
9%
2068
7%
720
32%
720
10%
1691
March11th to 20thNight
27%
720
8%
1979
5%
720
29%
720
10%
1647
March21st to endNight
26%
792
7%
2178
5%
792
27%
792
10%
1835
April1st to 10thNight
34%
668
8%
1794
5%
668
35%
668
12%
1458
April11th to 20thNight
39%
533
11%
1601
9%
533
40%
533
13%
1246
April21st to endNight
35%
540
10%
1620
8%
540
38%
540
13%
1265
May1st to 10thNight
50%
432
11%
1512
15%
432
51%
432
17%
1046
May11th to 20thNight
49%
354
9%
1391
15%
354
50%
354
11%
1035
May21st to endNight
52%
389
8%
1358
9%
388
54%
388
17%
960
June1st to 10thNight
45%
360
2%
1260
2%
360
45%
360
13%
946
June11th to 20thNight
45%
360
2%
1260
2%
360
45%
360
12%
952
June21st to endNight
53%
360
5%
1260
4%
360
54%
360
17%
890
July1st to 10thNight
58%
350
4%
1225
4%
350
58%
350
20%
816
July11th to 20thNight
69%
348
12%
1218
13%
348
70%
348
30%
713
July21st to endNight
67%
394
12%
1302
15%
372
68%
372
28%
765
August1st to 10thNight
60%
529
11%
1586
13%
527
60%
527
23%
1059
August11th to 20thNight
68%
534
17%
1602
17%
534
69%
534
33%
946
August21st to endNight
54%
594
14%
1782
12%
594
55%
594
22%
1193
September1st to 10thNight
61%
674
16%
1754
10%
674
62%
674
31%
1165
September11th to 20thNight
51%
720
14%
1944
10%
720
53%
720
22%
1397
September21st to endNight
47%
720
14%
1980
11%
720
49%
720
22%
1418
October1st to 10thNight
41%
720
10%
2146
9%
720
43%
720
18%
1554
October11th to 20thNight
34%
720
8%
2160
8%
720
36%
720
13%
1706
October21st to endNight
31%
792
11%
2538
10%
792
35%
792
12%
2002
November1st to 10thNight
22%
740
7%
2580
4%
740
26%
740
7%
2158
November11th to 20thNight
20%
760
6%
2660
5%
760
23%
760
7%
2216
November21st to endNight
28%
764
8%
2669
7%
764
31%
764
9%
2121
December1st to 10thNight
29%
850
9%
2850
6%
850
33%
850
10%
2242
December11th to 20thNight
20%
850
4%
3515
2%
849
23%
849
5%
3009
December21st to endNight
20%
932
5%
5195
6%
905
25%
905
4%
4485

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
28%9%36%5%3445%6%27%
74673
Night
33%10%35%5%24345%26%
75045
TransparencyDay
58%8%13%13%6%1
74353
Night
62%6%11%13%7%1
74883
SeeingDay
30%8%18%24%16%5%
14686
Night
36%6%11%22%18%6%
22767

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
53%10%2432222217%
1329
11th to 20thDay
41%11%45%424345%18%
1267
21st to endDay
40%12%46%6%3223418%
1552
February1st to 10thDay
43%12%3432436%416%
1620
11th to 20thDay
35%10%35%5%3333425%
1575
21st to endDay
31%9%47%5%2445%5%26%
1341
March1st to 10thDay
33%12%35%6%3435%6%21%
1891
11th to 20thDay
39%10%47%5%2434420%
1980
21st to endDay
37%10%37%5%3333422%
2178
April1st to 10thDay
33%11%46%5%24346%22%
2163
11th to 20thDay
29%10%46%5%35%45%6%24%
2308
21st to endDay
32%9%34433447%27%
2340
May1st to 10thDay
24%7%36%5%2445%7%31%
2447
11th to 20thDay
23%10%47%5%45%5%48%26%
2499
21st to endDay
22%9%47%6%36%46%7%27%
2917
June1st to 10thDay
27%10%46%5%35%5%47%25%
2700
11th to 20thDay
21%10%37%7%46%5%5%7%25%
2700
21st to endDay
22%8%37%5%35%45%7%31%
2700
July1st to 10thDay
19%8%36%5%3445%7%35%
2700
11th to 20thDay
14%9%35%4345%5%8%39%
2700
21st to endDay
13%8%24436%5%6%9%41%
2938
August1st to 10thDay
15%8%36%6%46%6%6%8%32%
2343
11th to 20thDay
11%8%26%5%35%5%6%9%40%
2298
21st to endDay
18%8%36%5%245%6%8%35%
2574
September1st to 10thDay
17%6%26%5%35%5%6%7%38%
2206
11th to 20thDay
22%8%36%5%46%5%5%6%31%
2012
21st to endDay
26%7%25%324336%38%
1980
October1st to 10thDay
26%7%25%6%36%5%6%6%29%
1813
11th to 20thDay
34%9%47%5%35%36%5%19%
1800
21st to endDay
36%7%35%42444426%
1818
November1st to 10thDay
42%10%35%5%335%4418%
1497
11th to 20thDay
42%10%35%42323421%
1520
21st to endDay
41%8%36%423335%22%
1510
December1st to 10thDay
32%10%25%5%345%35%25%
1330
11th to 20thDay
45%10%35%43433416%
1685
21st to endDay
51%10%35%42333313%
2442
January1st to 10thNight
47%11%35%5%2322316%
2836
11th to 20thNight
45%11%36%42333316%
2715
21st to endNight
42%10%35%43334418%
2799
February1st to 10thNight
40%11%35%424345%19%
2340
11th to 20thNight
32%12%35%423335%28%
2272
21st to endNight
32%12%37%5%2334425%
1911
March1st to 10thNight
32%12%46%6%3434421%
2068
11th to 20thNight
35%13%47%5%3334420%
1979
21st to endNight
38%11%47%5%2333321%
2178
April1st to 10thNight
32%10%45%6%34335%24%
1794
11th to 20thNight
31%12%35%43345%5%25%
1601
21st to endNight
30%9%46%6%3443329%
1620
May1st to 10thNight
23%8%35%5%2445%6%35%
1512
11th to 20thNight
22%9%45%6%36%6%5%7%27%
1391
21st to endNight
21%8%36%5%24447%35%
1358
June1st to 10thNight
26%9%36%6%45%6%36%27%
1260
11th to 20thNight
23%10%46%5%3445%7%29%
1260
21st to endNight
19%8%36%6%35%45%6%34%
1260
July1st to 10thNight
17%9%45%3235%5%7%40%
1260
11th to 20thNight
12%7%234235%5%8%50%
1260
21st to endNight
10%8%36%4245%46%48%
1379
August1st to 10thNight
13%9%46%435%45%7%40%
1593
11th to 20thNight
10%7%135%2435%8%51%
1602
21st to endNight
18%8%45%433447%39%
1782
September1st to 10thNight
14%8%25%5%2336%7%45%
1754
11th to 20thNight
22%9%35%424446%37%
1944
21st to endNight
29%6%24323347%38%
1980
October1st to 10thNight
27%9%37%5%2343434%
2146
11th to 20thNight
35%9%26%424345%25%
2160
21st to endNight
36%8%35%5%2333427%
2538
November1st to 10thNight
42%9%46%43434418%
2580
11th to 20thNight
38%11%46%5%3433420%
2660
21st to endNight
41%8%25%423335%23%
2669
December1st to 10thNight
33%11%36%5%34445%25%
2850
11th to 20thNight
46%11%36%42332416%
3520
21st to endNight
50%11%36%42323314%
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
77%347%6%2
1329
11th to 20thDay
72%5%8%8%5%3
1267
21st to endDay
73%47%11%41
1552
February1st to 10thDay
73%6%7%8%43
1620
11th to 20thDay
66%5%7%13%8%1
1584
21st to endDay
62%7%8%13%8%3
1341
March1st to 10thDay
65%8%10%13%4
1891
11th to 20thDay
71%6%9%9%41
1980
21st to endDay
69%7%10%11%3
2178
April1st to 10thDay
66%8%11%11%4
2163
11th to 20thDay
63%9%8%14%6%
2308
21st to endDay
61%9%9%14%7%1
2340
May1st to 10thDay
54%8%16%16%5%1
2447
11th to 20thDay
58%8%15%14%5%
2502
21st to endDay
55%12%16%14%4
2918
June1st to 10thDay
60%11%14%10%41
2700
11th to 20thDay
61%11%12%11%4
2700
21st to endDay
53%9%18%15%6%1
2700
July1st to 10thDay
50%8%19%14%8%1
2626
11th to 20thDay
43%8%23%20%5%
2619
21st to endDay
37%10%23%22%7%1
2775
August1st to 10thDay
44%9%21%18%7%1
2325
11th to 20thDay
38%10%22%17%10%3
2298
21st to endDay
44%12%21%18%5%
2574
September1st to 10thDay
45%9%16%20%8%2
2206
11th to 20thDay
52%9%13%14%11%1
2012
21st to endDay
49%8%15%19%8%2
1980
October1st to 10thDay
52%9%15%13%10%2
1813
11th to 20thDay
65%8%13%10%4
1800
21st to endDay
61%7%10%13%8%1
1818
November1st to 10thDay
71%7%9%8%5%1
1497
11th to 20thDay
70%5%7%9%8%2
1520
21st to endDay
67%49%13%5%2
1510
December1st to 10thDay
63%6%11%11%7%2
1330
11th to 20thDay
74%38%8%42
1688
21st to endDay
78%5%6%6%31
2442
January1st to 10thNight
77%36%7%6%2
2836
11th to 20thNight
74%48%7%43
2715
21st to endNight
72%47%12%5%1
2799
February1st to 10thNight
70%7%6%9%6%2
2340
11th to 20thNight
62%5%9%12%10%2
2274
21st to endNight
64%5%8%15%7%2
1911
March1st to 10thNight
67%5%9%14%4
2068
11th to 20thNight
69%5%10%10%5%2
1980
21st to endNight
71%410%11%4
2178
April1st to 10thNight
64%6%10%13%6%
1794
11th to 20thNight
60%7%10%16%7%
1601
21st to endNight
62%5%8%15%8%1
1620
May1st to 10thNight
50%7%17%19%7%
1512
11th to 20thNight
58%8%11%18%5%1
1391
21st to endNight
51%7%18%20%4
1358
June1st to 10thNight
58%7%17%12%42
1260
11th to 20thNight
57%9%15%14%5%
1260
21st to endNight
50%8%18%16%6%1
1260
July1st to 10thNight
44%9%18%18%11%1
1225
11th to 20thNight
32%9%23%27%8%1
1218
21st to endNight
35%7%21%25%10%2
1302
August1st to 10thNight
44%8%18%20%10%1
1586
11th to 20thNight
33%6%24%21%10%5%
1602
21st to endNight
43%9%18%24%5%1
1782
September1st to 10thNight
39%7%17%25%11%2
1754
11th to 20thNight
49%7%13%16%14%2
1944
21st to endNight
48%8%14%18%9%3
1980
October1st to 10thNight
53%6%12%16%12%1
2146
11th to 20thNight
63%5%13%11%7%
2160
21st to endNight
63%6%9%13%8%1
2538
November1st to 10thNight
71%6%7%10%5%1
2580
11th to 20thNight
71%6%7%8%6%2
2660
21st to endNight
67%5%9%11%6%2
2669
December1st to 10thNight
65%5%11%11%6%3
2850
11th to 20thNight
76%5%7%6%5%2
3516
21st to endNight
77%5%7%7%31
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
51%11%14%17%43
180
11th to 20thDay
51%10%15%11%10%3
162
21st to endDay
44%9%14%16%13%5%
329
February1st to 10thDay
50%8%17%20%4
340
11th to 20thDay
41%10%19%19%10%1
335
21st to endDay
35%12%24%20%7%2
280
March1st to 10thDay
36%10%17%22%13%2
381
11th to 20thDay
40%9%19%20%10%3
420
21st to endDay
43%9%16%20%10%2
462
April1st to 10thDay
41%9%20%20%8%2
420
11th to 20thDay
31%9%24%17%14%4
412
21st to endDay
36%12%23%17%8%3
420
May1st to 10thDay
24%9%21%26%16%3
423
11th to 20thDay
25%6%20%28%18%3
469
21st to endDay
21%9%20%32%15%3
680
June1st to 10thDay
31%9%17%27%13%3
630
11th to 20thDay
22%10%28%24%13%3
630
21st to endDay
21%6%19%28%21%5%
630
July1st to 10thDay
22%5%18%30%22%4
621
11th to 20thDay
14%6%20%32%23%6%
618
21st to endDay
12%216%28%33%8%
684
August1st to 10thDay
16%6%13%28%28%9%
457
11th to 20thDay
13%415%27%31%10%
437
21st to endDay
20%8%16%28%20%7%
495
September1st to 10thDay
21%7%20%29%17%6%
450
11th to 20thDay
27%8%14%22%21%8%
450
21st to endDay
29%7%17%25%16%6%
450
October1st to 10thDay
29%7%14%25%19%6%
450
11th to 20thDay
40%9%14%17%14%6%
450
21st to endDay
37%11%19%18%11%4
414
November1st to 10thDay
44%6%17%20%10%3
189
11th to 20thDay
45%8%13%12%11%11%
180
21st to endDay
47%8%16%9%12%8%
180
December1st to 10thDay
41%11%14%13%11%9%
180
11th to 20thDay
46%7%15%17%12%4
180
21st to endDay
49%8%13%19%10%1
198
January1st to 10thNight
54%10%13%16%7%2
850
11th to 20thNight
51%6%11%20%11%1
805
21st to endNight
47%6%11%20%14%1
874
February1st to 10thNight
48%6%16%24%5%1
720
11th to 20thNight
38%8%16%26%12%
704
21st to endNight
41%7%16%24%9%2
592
March1st to 10thNight
38%10%11%18%17%4
720
11th to 20thNight
40%10%13%23%12%2
720
21st to endNight
42%8%13%17%16%4
792
April1st to 10thNight
39%6%12%22%17%4
668
11th to 20thNight
37%7%8%27%17%4
533
21st to endNight
33%6%14%27%16%3
540
May1st to 10thNight
28%6%7%27%27%6%
432
11th to 20thNight
26%5%6%22%33%8%
354
21st to endNight
24%5%7%28%29%6%
389
June1st to 10thNight
30%49%23%28%6%
360
11th to 20thNight
27%6%9%29%24%5%
360
21st to endNight
21%5%9%27%30%8%
360
July1st to 10thNight
23%36%17%37%14%
350
11th to 20thNight
15%27%22%39%16%
348
21st to endNight
13%3320%40%21%
394
August1st to 10thNight
20%2216%35%25%
529
11th to 20thNight
15%1418%40%23%
534
21st to endNight
22%46%24%34%10%
594
September1st to 10thNight
19%37%25%32%15%
674
11th to 20thNight
25%38%21%28%15%
720
21st to endNight
32%410%24%24%6%
720
October1st to 10thNight
31%410%23%25%7%
720
11th to 20thNight
39%49%23%19%6%
720
21st to endNight
42%7%11%25%11%4
792
November1st to 10thNight
46%7%18%21%8%
740
11th to 20thNight
43%12%15%19%9%3
760
21st to endNight
44%8%13%21%10%3
764
December1st to 10thNight
37%9%16%22%12%4
850
11th to 20thNight
48%9%16%17%10%1
850
21st to endNight
49%9%16%21%5%
935
Page generated at 2024-01-08 19:31:23. Version ac07

Copyright 2024 Attilla Danko


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