Tumbler Ridge
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tumbler Ridge clear sky chart from 2005-11-05 to 2018-02-14.

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
30%
15675
9%
48851
5%
15643
34%
15643
15%
35238

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 15thNight
23%
1012
8%
3097
5%
1007
27%
1007
11%
2367
January16th to endNight
20%
880
12%
3120
6%
880
28%
880
9%
2287
February1st to 15thNight
26%
755
9%
2639
6%
754
31%
754
11%
1940
February16th to endNight
29%
632
9%
2047
7%
632
34%
632
13%
1516
March1st to 15thNight
22%
720
12%
2140
6%
720
28%
720
13%
1594
March16th to endNight
35%
768
10%
2015
4%
767
38%
767
19%
1501
April1st to 15thNight
34%
695
12%
1775
4%
695
40%
695
18%
1321
April16th to endNight
33%
375
9%
1455
8%
375
39%
375
11%
1051
May1st to 15thNight
39%
359
4%
1428
3%
359
41%
359
18%
920
May16th to endNight
39%
375
0%
1122
0%
374
39%
374
15%
842
June1st to 15thNight
40%
360
0%
1080
0%
360
40%
360
18%
769
June16th to endNight
41%
360
0%
1080
0%
360
41%
360
19%
751
July1st to 15thNight
42%
340
0%
1020
0%
340
42%
340
23%
666
July16th to endNight
51%
376
0%
1169
0%
354
52%
354
28%
707
August1st to 15thNight
54%
360
6%
1403
7%
358
56%
358
23%
821
August16th to endNight
41%
490
11%
1636
9%
490
46%
490
17%
1095
September1st to 15thNight
43%
720
11%
1800
6%
720
44%
720
29%
1222
September16th to endNight
30%
716
13%
1962
6%
716
34%
716
18%
1405
October1st to 15thNight
29%
720
10%
2160
4%
720
35%
720
15%
1570
October16th to endNight
20%
768
10%
2559
4%
768
29%
768
11%
1882
November1st to 15thNight
21%
793
13%
2693
7%
793
30%
793
11%
1907
November16th to endNight
21%
993
10%
3003
4%
993
27%
993
11%
2281
December1st to 15thNight
21%
1020
10%
3120
5%
1020
26%
1020
12%
2362
December16th to endNight
25%
1088
13%
3328
5%
1088
32%
1088
12%
2461

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
10%9%48%7%46%6%6%7%29%
49275
Night
7%9%47%6%45%5%6%8%32%
48987
TransparencyDay
52%9%16%16%4
48912
Night
48%9%16%18%5%
48856
SeeingDay
20%16%29%20%10%2
7305
Night
16%16%28%24%12%1
15682

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 15thDay
39%5%10%7%47%5%7%10%28%
1184
16th to endDay
411%49%7%35%5%6%8%30%
1456
February1st to 15thDay
410%5%11%7%47%5%47%30%
1524
16th to endDay
412%6%11%7%37%6%5%7%27%
1427
March1st to 15thDay
311%6%11%8%47%5%7%6%26%
1818
16th to endDay
5%14%6%9%7%37%6%7%8%22%
2205
April1st to 15thDay
7%14%5%9%8%46%5%6%7%25%
2173
16th to endDay
11%12%5%10%6%46%5%5%7%24%
2505
May1st to 15thDay
9%10%5%7%7%36%5%6%7%30%
2517
16th to endDay
17%10%48%7%36%6%5%7%22%
2991
June1st to 15thDay
16%9%37%7%46%6%5%7%26%
2880
16th to endDay
13%7%47%7%36%5%7%7%29%
2880
July1st to 15thDay
15%5%25%5%46%6%5%8%34%
2880
16th to endDay
9%4246%47%7%7%9%35%
2917
August1st to 15thDay
10%5%25%6%36%6%7%8%36%
2549
16th to endDay
11%6%36%7%45%6%6%8%34%
2563
September1st to 15thDay
13%7%35%5%45%447%38%
2160
16th to endDay
11%8%25%5%46%5%6%9%34%
1998
October1st to 15thDay
11%13%38%6%35%5%47%30%
1800
16th to endDay
10%12%47%6%346%6%9%27%
1664
November1st to 15thDay
7%12%6%7%5%36%6%47%31%
1481
16th to endDay
310%7%11%9%45%6%8%6%28%
1285
December1st to 15thDay
7%10%6%9%6%35%6%49%29%
1170
16th to endDay
111%49%8%5%7%5%6%8%29%
1248
January1st to 15thNight
311%6%10%8%35%6%6%9%28%
3097
16th to endNight
5%11%5%8%7%46%6%6%8%29%
3120
February1st to 15thNight
5%11%5%10%6%46%5%7%7%28%
2627
16th to endNight
39%7%11%8%47%6%6%8%26%
2047
March1st to 15thNight
29%6%11%9%46%5%6%9%29%
2140
16th to endNight
5%13%6%6%6%35%5%8%7%30%
2015
April1st to 15thNight
7%8%5%6%7%37%5%6%7%34%
1775
16th to endNight
10%11%48%5%35%5%6%7%29%
1455
May1st to 15thNight
9%8%35%5%26%6%8%8%36%
1428
16th to endNight
18%9%35%6%36%5%5%9%26%
1122
June1st to 15thNight
12%6%48%5%35%5%46%35%
1080
16th to endNight
11%8%35%6%25%5%7%7%35%
1080
July1st to 15thNight
13%425%435%5%6%8%40%
1080
16th to endNight
6%423437%7%6%8%46%
1250
August1st to 15thNight
9%3245%345%6%7%47%
1410
16th to endNight
8%5%26%6%46%7%8%9%35%
1636
September1st to 15thNight
9%6%15%5%3445%7%46%
1800
16th to endNight
10%7%25%5%345%7%10%35%
1962
October1st to 15thNight
11%12%37%5%345%6%7%34%
2160
16th to endNight
9%10%6%7%5%45%5%6%7%31%
2559
November1st to 15thNight
6%10%38%6%45%5%6%8%34%
2693
16th to endNight
5%13%5%9%6%46%5%6%8%28%
3003
December1st to 15thNight
411%5%9%8%46%6%6%7%31%
3120
16th to endNight
211%5%8%8%45%5%6%6%32%
3328

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 15thDay
51%13%18%12%21
1184
16th to endDay
51%10%17%13%5%1
1456
February1st to 15thDay
53%10%13%13%7%
1524
16th to endDay
55%6%16%15%41
1427
March1st to 15thDay
56%7%14%15%4
1818
16th to endDay
57%9%17%12%4
2205
April1st to 15thDay
58%7%14%15%4
2173
16th to endDay
59%8%13%13%4
2505
May1st to 15thDay
53%7%15%14%8%
2517
16th to endDay
61%7%12%16%3
2996
June1st to 15thDay
57%7%12%18%4
2880
16th to endDay
53%8%14%17%5%
2880
July1st to 15thDay
47%8%15%21%5%1
2711
16th to endDay
42%11%23%18%3
2736
August1st to 15thDay
41%12%20%20%4
2531
16th to endDay
46%10%21%17%3
2563
September1st to 15thDay
45%8%22%17%6%
2160
16th to endDay
46%10%19%18%4
1998
October1st to 15thDay
53%8%20%14%2
1800
16th to endDay
51%10%20%15%1
1664
November1st to 15thDay
54%8%16%16%31
1481
16th to endDay
54%10%16%12%4
1285
December1st to 15thDay
52%10%13%18%4
1170
16th to endDay
52%9%14%15%8%
1248
January1st to 15thNight
52%12%17%13%21
3097
16th to endNight
51%10%14%14%6%1
3120
February1st to 15thNight
53%9%15%13%7%
2639
16th to endNight
53%8%15%16%41
2047
March1st to 15thNight
52%8%13%18%5%
2140
16th to endNight
49%8%18%18%4
2019
April1st to 15thNight
48%9%13%23%5%
1775
16th to endNight
53%9%14%15%6%
1455
May1st to 15thNight
42%9%16%20%10%
1429
16th to endNight
54%7%15%16%5%
1122
June1st to 15thNight
49%6%14%23%5%
1080
16th to endNight
47%7%14%23%6%
1080
July1st to 15thNight
40%7%18%25%7%
1020
16th to endNight
31%10%29%24%4
1169
August1st to 15thNight
34%9%21%29%4
1403
16th to endNight
40%13%20%20%4
1636
September1st to 15thNight
38%8%22%22%7%
1800
16th to endNight
42%12%18%19%6%
1962
October1st to 15thNight
49%9%18%18%3
2160
16th to endNight
51%9%18%17%2
2559
November1st to 15thNight
48%9%16%18%5%
2693
16th to endNight
54%10%14%15%41
3003
December1st to 15thNight
52%10%15%16%4
3120
16th to endNight
50%10%13%18%6%
3328

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 15thDay
13%12%18%30%11%14%
90
16th to endDay
16%19%30%22%10%
96
February1st to 15thDay
20%20%31%18%7%
111
16th to endDay
15%18%34%20%9%
213
March1st to 15thDay
17%30%32%14%4
270
16th to endDay
19%20%33%21%5%
288
April1st to 15thDay
30%21%24%16%41
269
16th to endDay
22%22%32%15%4
270
May1st to 15thDay
20%22%29%18%7%1
294
16th to endDay
22%10%26%21%14%3
705
June1st to 15thDay
22%14%25%21%12%3
675
16th to endDay
19%12%29%22%12%3
675
July1st to 15thDay
18%13%26%23%14%2
645
16th to endDay
12%13%34%27%10%1
585
August1st to 15thDay
13%11%27%27%16%2
344
16th to endDay
22%22%32%17%31
332
September1st to 15thDay
25%16%31%15%7%4
315
16th to endDay
22%23%30%15%6%
315
October1st to 15thDay
34%17%25%13%7%2
315
16th to endDay
24%24%24%14%10%2
132
November1st to 15thDay
26%24%25%15%6%1
90
16th to endDay
14%22%30%21%10%2
90
December1st to 15thDay
10%12%30%30%14%3
90
16th to endDay
14%11%28%29%14%2
96
January1st to 15thNight
16%19%27%25%8%1
1012
16th to endNight
20%24%27%23%31
880
February1st to 15thNight
17%20%25%21%12%1
761
16th to endNight
8%14%31%29%13%1
632
March1st to 15thNight
12%20%36%24%5%1
720
16th to endNight
14%12%27%26%17%1
768
April1st to 15thNight
13%13%28%29%13%2
695
16th to endNight
18%14%26%23%16%1
375
May1st to 15thNight
14%10%27%26%18%3
360
16th to endNight
22%9%18%26%20%3
375
June1st to 15thNight
15%8%25%28%20%1
360
16th to endNight
15%10%23%27%21%1
360
July1st to 15thNight
16%7%27%30%17%1
340
16th to endNight
8%9%26%32%19%3
376
August1st to 15thNight
11%421%26%31%4
360
16th to endNight
13%10%28%24%21%1
490
September1st to 15thNight
15%9%24%26%20%2
720
16th to endNight
18%18%29%20%12%1
716
October1st to 15thNight
24%16%24%23%9%1
720
16th to endNight
21%20%29%21%6%
768
November1st to 15thNight
21%23%26%19%7%
793
16th to endNight
17%22%31%21%6%
993
December1st to 15thNight
15%19%33%22%7%1
1020
16th to endNight
16%17%29%25%10%1
1088
Page generated at 2018-02-15 07:58:49. Version ac04

Copyright 2018 A. Danko


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