Pitt Meadows
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pitt Meadows clear sky chart from 2005-11-06 to 2024-02-05.

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
31%
22636
9%
80678
7%
22505
35%
22505
12%
61687

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
14%
847
5%
4715
4%
816
18%
816
3%
4091
January11th to 20thNight
20%
840
15%
4602
4%
816
24%
816
6%
3185
January21st to endNight
19%
836
5%
4852
6%
814
24%
814
4%
4287
February1st to 10thNight
16%
738
8%
2397
3%
738
23%
738
8%
1988
February11th to 20thNight
18%
700
8%
2274
4%
700
25%
700
9%
1855
February21st to endNight
22%
592
12%
1898
6%
592
29%
592
11%
1482
March1st to 10thNight
25%
720
7%
2112
5%
720
27%
720
11%
1700
March11th to 20thNight
21%
720
8%
1980
4%
720
24%
720
10%
1638
March21st to endNight
22%
792
4%
2112
1%
792
23%
792
9%
1812
April1st to 10thNight
25%
720
6%
1800
3%
720
26%
720
12%
1497
April11th to 20thNight
24%
634
10%
1702
4%
634
28%
634
13%
1347
April21st to endNight
26%
476
6%
1556
4%
476
28%
476
11%
1227
May1st to 10thNight
42%
360
10%
1440
13%
360
45%
360
16%
969
May11th to 20thNight
53%
354
9%
1416
15%
354
55%
354
15%
956
May21st to endNight
48%
388
5%
1518
7%
388
51%
388
15%
1047
June1st to 10thNight
43%
360
3%
1260
3%
360
43%
360
15%
924
June11th to 20thNight
39%
360
2%
1260
1%
360
40%
360
12%
966
June21st to endNight
53%
360
6%
1260
2%
360
54%
360
22%
807
July1st to 10thNight
62%
350
7%
1225
7%
350
62%
350
27%
732
July11th to 20thNight
68%
348
14%
1218
18%
348
70%
348
33%
662
July21st to endNight
77%
394
18%
1455
28%
372
79%
372
41%
663
August1st to 10thNight
73%
359
17%
1425
25%
357
74%
357
35%
691
August11th to 20thNight
76%
534
21%
1602
21%
534
78%
534
45%
826
August21st to endNight
60%
661
18%
1849
15%
661
62%
661
31%
1160
September1st to 10thNight
59%
720
17%
1800
10%
720
60%
720
35%
1161
September11th to 20thNight
48%
720
17%
1800
10%
720
50%
720
27%
1269
September21st to endNight
43%
720
15%
2059
11%
720
46%
720
20%
1469
October1st to 10thNight
40%
720
9%
2160
8%
720
42%
720
19%
1540
October11th to 20thNight
30%
720
9%
2160
7%
720
33%
720
14%
1653
October21st to endNight
24%
792
10%
2519
7%
792
29%
792
11%
1959
November1st to 10thNight
16%
740
5%
2590
3%
740
20%
740
7%
2158
November11th to 20thNight
17%
760
8%
2660
4%
760
22%
760
7%
2181
November21st to endNight
15%
760
5%
2660
2%
760
20%
760
7%
2196
December1st to 10thNight
24%
760
11%
2660
7%
760
29%
760
10%
2081
December11th to 20thNight
11%
847
3%
3508
1%
846
14%
846
4%
3083
December21st to endNight
9%
934
4%
5174
1%
905
16%
905
3%
4425

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
27%8%36%5%34445%29%
77811
Night
31%9%35%5%34445%28%
80992
TransparencyDay
57%8%13%14%7%1
77522
Night
59%7%12%13%7%2
80861
SeeingDay
33%11%21%23%10%2
14220
Night
37%7%18%23%13%1
22651

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
45%13%36%5%3434410%
2219
11th to 20thDay
31%13%46%5%3423427%
2204
21st to endDay
58%9%25%42233310%
2803
February1st to 10thDay
37%10%47%6%34445%17%
1657
11th to 20thDay
34%9%37%6%35%335%21%
1575
21st to endDay
26%13%5%8%6%35%345%21%
1357
March1st to 10thDay
33%11%46%6%35%445%19%
1844
11th to 20thDay
37%11%46%6%34335%19%
1980
21st to endDay
32%10%48%6%445%4418%
2243
April1st to 10thDay
31%9%47%5%5%45%5%6%18%
2160
11th to 20thDay
25%10%48%7%45%45%6%23%
2205
21st to endDay
26%10%47%6%35%5%5%5%24%
2403
May1st to 10thDay
21%8%37%6%46%5%45%33%
2520
11th to 20thDay
18%8%37%6%445%5%8%30%
2477
21st to endDay
22%8%48%6%34446%29%
2753
June1st to 10thDay
25%7%46%6%35%45%6%29%
2700
11th to 20thDay
25%9%47%6%46%5%5%7%22%
2700
21st to endDay
17%8%46%5%36%5%5%7%35%
2700
July1st to 10thDay
15%5%25%4235%5%6%48%
2700
11th to 20thDay
13%5%25%42445%6%50%
2700
21st to endDay
10%323323346%60%
2773
August1st to 10thDay
12%5%24433346%54%
2503
11th to 20thDay
10%5%2432445%6%55%
2298
21st to endDay
16%6%25%5%335%5%7%44%
2507
September1st to 10thDay
17%7%35%423446%45%
2160
11th to 20thDay
20%7%35%5%3344440%
2160
21st to endDay
27%6%25%5%34445%35%
1898
October1st to 10thDay
27%8%35%5%2345%6%33%
1800
11th to 20thDay
34%8%37%5%33446%23%
1800
21st to endDay
39%7%35%5%3335%6%22%
1832
November1st to 10thDay
43%8%45%6%34435%16%
1488
11th to 20thDay
41%10%36%43433321%
1520
21st to endDay
41%10%5%5%4235%4417%
1520
December1st to 10thDay
35%11%46%5%2333423%
1520
11th to 20thDay
39%14%47%5%3443411%
1690
21st to endDay
44%14%48%5%3433310%
2442
January1st to 10thNight
43%12%46%5%3343314%
4726
11th to 20thNight
34%8%2442345%7%26%
4692
21st to endNight
55%11%3442222312%
4852
February1st to 10thNight
38%10%36%5%33345%20%
2397
11th to 20thNight
31%13%47%5%23345%24%
2272
21st to endNight
31%11%35%5%3345%5%27%
1898
March1st to 10thNight
32%10%35%5%35%5%4423%
2112
11th to 20thNight
36%10%36%6%44345%21%
1979
21st to endNight
35%11%46%5%3444420%
2112
April1st to 10thNight
30%9%47%5%45%446%22%
1800
11th to 20thNight
23%10%48%5%3445%6%27%
1702
21st to endNight
28%8%46%5%46%446%25%
1556
May1st to 10thNight
18%7%36%5%25%5%5%6%39%
1440
11th to 20thNight
17%6%26%6%36%5%7%7%35%
1416
21st to endNight
19%7%25%5%35%5%5%7%35%
1518
June1st to 10thNight
24%7%35%6%45%46%6%31%
1260
11th to 20thNight
18%11%47%6%445%6%8%27%
1260
21st to endNight
15%6%345%35%46%6%43%
1260
July1st to 10thNight
11%5%245%34347%52%
1260
11th to 20thNight
10%324423446%59%
1260
21st to endNight
5%213324445%66%
1541
August1st to 10thNight
9%5%24312345%62%
1433
11th to 20thNight
8%312223348%64%
1602
21st to endNight
10%5%25%435%5%6%9%46%
1849
September1st to 10thNight
11%425%4335%5%6%55%
1800
11th to 20thNight
21%6%35%424345%43%
1800
21st to endNight
23%6%27%6%34345%38%
2059
October1st to 10thNight
22%8%25%5%35%445%38%
2160
11th to 20thNight
32%8%26%5%23445%29%
2160
21st to endNight
35%7%25%433345%27%
2519
November1st to 10thNight
41%9%36%5%3433418%
2590
11th to 20thNight
39%9%35%42334423%
2660
21st to endNight
39%9%46%5%345%3319%
2660
December1st to 10thNight
33%9%36%5%3433425%
2660
11th to 20thNight
46%13%46%5%3233312%
3513
21st to endNight
44%13%46%5%2232315%
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%8%7%6%21
2219
11th to 20thDay
62%7%7%13%7%4
2225
21st to endDay
81%46%6%2
2803
February1st to 10thDay
72%6%8%8%42
1657
11th to 20thDay
67%7%9%10%7%1
1584
21st to endDay
65%8%9%10%5%2
1357
March1st to 10thDay
67%8%11%9%41
1844
11th to 20thDay
71%6%7%10%41
1980
21st to endDay
70%7%10%11%2
2243
April1st to 10thDay
67%9%13%8%2
2160
11th to 20thDay
64%8%10%10%7%1
2205
21st to endDay
62%9%12%10%7%1
2403
May1st to 10thDay
54%9%15%15%7%1
2520
11th to 20thDay
52%11%16%16%6%
2480
21st to endDay
57%9%15%16%3
2754
June1st to 10thDay
57%8%17%12%5%2
2700
11th to 20thDay
62%10%16%9%3
2700
21st to endDay
49%8%17%16%8%2
2700
July1st to 10thDay
37%9%16%23%12%3
2626
11th to 20thDay
34%7%20%28%9%2
2619
21st to endDay
23%8%19%32%14%3
2619
August1st to 10thDay
31%10%17%28%11%2
2486
11th to 20thDay
29%9%20%26%14%2
2298
21st to endDay
39%9%19%25%6%1
2507
September1st to 10thDay
41%8%15%22%11%4
2160
11th to 20thDay
48%8%11%17%14%2
2160
21st to endDay
50%9%15%15%10%1
1898
October1st to 10thDay
51%8%15%16%10%
1800
11th to 20thDay
61%8%12%14%41
1800
21st to endDay
63%7%11%10%8%1
1832
November1st to 10thDay
71%7%10%8%31
1488
11th to 20thDay
69%6%8%8%6%2
1520
21st to endDay
69%6%8%9%7%1
1520
December1st to 10thDay
65%8%6%11%9%1
1520
11th to 20thDay
72%7%11%6%32
1693
21st to endDay
78%8%6%6%21
2442
January1st to 10thNight
76%7%7%7%21
4726
11th to 20thNight
56%7%10%15%9%3
4733
21st to endNight
80%45%8%31
4852
February1st to 10thNight
68%7%10%9%42
2397
11th to 20thNight
66%7%8%10%7%2
2274
21st to endNight
61%7%10%14%6%2
1898
March1st to 10thNight
62%8%13%12%5%
2112
11th to 20thNight
66%6%12%9%6%1
1980
21st to endNight
69%8%13%8%2
2112
April1st to 10thNight
63%8%14%12%2
1800
11th to 20thNight
59%8%11%13%7%2
1702
21st to endNight
61%9%13%10%7%1
1556
May1st to 10thNight
47%9%19%17%7%1
1440
11th to 20thNight
45%12%20%16%7%
1416
21st to endNight
49%9%20%17%5%
1518
June1st to 10thNight
54%8%18%13%5%2
1260
11th to 20thNight
56%10%18%12%3
1260
21st to endNight
41%9%21%18%8%3
1260
July1st to 10thNight
36%7%14%25%14%4
1225
11th to 20thNight
29%7%20%29%13%1
1218
21st to endNight
19%8%14%35%20%5%
1455
August1st to 10thNight
25%6%19%29%18%3
1425
11th to 20thNight
20%8%24%29%14%6%
1602
21st to endNight
34%9%19%27%10%1
1849
September1st to 10thNight
32%10%16%24%14%4
1800
11th to 20thNight
45%6%13%16%16%4
1800
21st to endNight
48%8%15%19%9%2
2059
October1st to 10thNight
49%8%14%18%9%1
2160
11th to 20thNight
57%7%15%14%6%1
2160
21st to endNight
60%8%10%14%8%
2519
November1st to 10thNight
71%6%10%9%31
2590
11th to 20thNight
68%7%8%9%6%2
2660
21st to endNight
69%7%9%7%7%1
2660
December1st to 10thNight
63%6%10%11%8%1
2660
11th to 20thNight
77%6%7%5%31
3509
21st to endNight
75%6%7%8%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
49%10%19%10%8%3
180
11th to 20thDay
54%8%13%17%7%
180
21st to endDay
53%8%16%16%7%
207
February1st to 10thDay
50%11%18%15%5%1
353
11th to 20thDay
44%13%19%20%41
335
21st to endDay
39%14%25%16%6%
292
March1st to 10thDay
41%15%20%18%5%1
420
11th to 20thDay
43%12%18%18%8%1
420
21st to endDay
46%14%17%16%6%1
462
April1st to 10thDay
42%14%18%19%6%1
420
11th to 20thDay
35%14%22%18%10%1
412
21st to endDay
34%15%24%17%9%1
420
May1st to 10thDay
27%13%25%25%9%1
423
11th to 20thDay
30%8%20%26%12%4
448
21st to endDay
26%14%25%22%10%4
515
June1st to 10thDay
30%12%24%24%8%2
630
11th to 20thDay
33%15%23%22%7%1
630
21st to endDay
23%11%22%28%13%2
630
July1st to 10thDay
22%8%26%31%11%3
621
11th to 20thDay
17%10%26%32%12%3
618
21st to endDay
12%7%26%37%13%6%
519
August1st to 10thDay
18%10%18%34%14%7%
447
11th to 20thDay
13%5%24%35%17%5%
437
21st to endDay
19%13%24%28%13%3
495
September1st to 10thDay
25%10%24%28%11%1
450
11th to 20thDay
29%8%19%27%14%2
450
21st to endDay
29%12%18%26%12%3
450
October1st to 10thDay
33%7%22%21%14%2
450
11th to 20thDay
42%8%14%20%13%3
450
21st to endDay
42%10%20%17%9%2
358
November1st to 10thDay
47%10%15%22%6%
180
11th to 20thDay
54%6%9%13%14%3
180
21st to endDay
51%9%17%9%8%7%
180
December1st to 10thDay
51%11%12%6%16%4
180
11th to 20thDay
56%8%14%17%42
180
21st to endDay
51%11%18%16%41
198
January1st to 10thNight
55%9%18%14%4
850
11th to 20thNight
49%5%20%23%3
846
21st to endNight
47%10%18%20%4
836
February1st to 10thNight
46%8%24%18%3
738
11th to 20thNight
42%10%22%21%5%
704
21st to endNight
37%11%25%20%7%
592
March1st to 10thNight
40%9%21%21%9%
720
11th to 20thNight
46%9%19%20%5%
720
21st to endNight
45%8%18%20%8%1
792
April1st to 10thNight
39%7%21%23%9%1
720
11th to 20thNight
33%10%24%23%9%1
634
21st to endNight
38%6%22%24%9%
476
May1st to 10thNight
24%6%21%30%18%1
360
11th to 20thNight
23%5%12%34%23%3
354
21st to endNight
25%417%32%22%
389
June1st to 10thNight
29%5%15%32%17%2
360
11th to 20thNight
25%11%17%26%19%2
360
21st to endNight
21%5%16%33%23%2
360
July1st to 10thNight
14%6%9%35%33%3
350
11th to 20thNight
12%410%33%36%5%
348
21st to endNight
8%37%34%45%4
394
August1st to 10thNight
12%26%27%47%6%
359
11th to 20thNight
10%27%36%40%4
534
21st to endNight
18%312%35%30%2
661
September1st to 10thNight
15%317%37%27%1
720
11th to 20thNight
26%414%26%26%3
720
21st to endNight
32%6%12%33%17%1
720
October1st to 10thNight
31%418%28%16%1
720
11th to 20thNight
43%5%17%22%12%1
720
21st to endNight
42%7%21%21%7%1
792
November1st to 10thNight
51%9%21%18%2
740
11th to 20thNight
51%7%21%15%6%1
760
21st to endNight
47%10%20%16%7%1
760
December1st to 10thNight
40%9%23%23%6%
760
11th to 20thNight
55%10%19%13%2
847
21st to endNight
52%10%24%12%1
935
Page generated at 2024-02-02 02:20:32. Version ac07

Copyright 2024 Attilla Danko


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