Peace River
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Peace River clear sky chart from 2005-11-05 to 2017-09-16.

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
46%
15094
9%
46663
7%
15069
48%
15069
19%
32978

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
36%
926
6%
2865
5%
925
38%
925
12%
2246
January16th to endNight
35%
909
12%
2939
10%
909
39%
909
15%
2150
February1st to 15thNight
47%
696
10%
2464
11%
696
49%
696
16%
1742
February16th to endNight
51%
632
11%
2054
12%
632
53%
632
19%
1450
March1st to 15thNight
43%
720
14%
2160
11%
720
46%
720
20%
1536
March16th to endNight
53%
767
15%
2019
10%
767
54%
767
26%
1408
April1st to 15thNight
49%
650
13%
1730
8%
650
52%
650
25%
1220
April16th to endNight
44%
408
10%
1488
13%
408
47%
408
17%
1011
May1st to 15thNight
50%
359
3%
1311
2%
359
51%
359
22%
811
May16th to endNight
53%
374
0%
1176
0%
374
53%
374
24%
760
June1st to 15thNight
56%
360
0%
1080
0%
360
56%
360
23%
739
June16th to endNight
60%
360
0%
1080
0%
360
60%
360
27%
694
July1st to 15thNight
64%
340
0%
1020
0%
340
64%
340
29%
641
July16th to endNight
64%
376
0%
1090
0%
354
65%
354
29%
676
August1st to 15thNight
73%
360
4%
1409
4%
358
74%
358
28%
775
August16th to endNight
58%
463
12%
1609
15%
463
60%
463
25%
986
September1st to 15thNight
62%
699
13%
1779
9%
699
63%
699
34%
1162
September16th to endNight
49%
660
16%
1811
9%
660
53%
660
27%
1216
October1st to 15thNight
45%
660
12%
2024
9%
660
49%
660
19%
1441
October16th to endNight
40%
704
11%
2292
8%
704
45%
704
15%
1649
November1st to 15thNight
36%
846
13%
2596
10%
846
41%
846
18%
1865
November16th to endNight
37%
903
7%
2715
5%
903
40%
903
13%
2126
December1st to 15thNight
31%
930
7%
2880
4%
930
33%
930
10%
2337
December16th to endNight
37%
992
10%
3072
6%
992
41%
992
14%
2337

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
11%8%47%6%45%5%6%7%32%
48155
Night
9%9%48%7%45%5%6%7%30%
46787
TransparencyDay
48%6%18%20%5%
47784
Night
50%6%16%19%6%
46663
SeeingDay
14%6%19%29%22%7%
6936
Night
13%419%37%21%3
15109

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
10%13%6%8%11%38%5%5%7%19%
1074
16th to endDay
9%12%48%7%5%5%45%6%30%
1296
February1st to 15thDay
8%10%411%7%37%7%5%8%24%
1400
16th to endDay
6%10%6%10%9%6%7%6%6%9%21%
1419
March1st to 15thDay
7%13%5%9%7%46%5%5%7%28%
1800
16th to endDay
8%12%47%6%35%6%6%8%29%
2202
April1st to 15thDay
8%10%46%7%45%45%7%34%
2218
16th to endDay
11%10%5%7%6%45%447%31%
2469
May1st to 15thDay
11%5%36%5%35%5%6%8%38%
2639
16th to endDay
14%6%35%5%35%46%8%35%
2935
June1st to 15thDay
16%7%37%6%45%5%6%7%30%
2880
16th to endDay
16%5%25%6%45%5%6%6%35%
2880
July1st to 15thDay
13%5%25%435%5%6%8%38%
2880
16th to endDay
11%5%25%435%5%6%8%40%
3005
August1st to 15thDay
10%425%6%45%6%6%8%38%
2542
16th to endDay
12%5%25%6%45%5%6%9%36%
2593
September1st to 15thDay
12%5%246%35%5%5%8%40%
2180
16th to endDay
11%7%36%5%3446%8%38%
1838
October1st to 15thDay
15%9%47%6%35%5%5%6%30%
1603
16th to endDay
13%12%5%8%6%3445%7%26%
1579
November1st to 15thDay
10%10%6%8%6%35%5%6%7%28%
1249
16th to endDay
7%14%7%11%7%5%6%45%6%23%
1242
December1st to 15thDay
11%14%5%10%11%5%7%5%5%7%15%
1080
16th to endDay
7%12%6%11%10%5%6%6%6%6%21%
1152
January1st to 15thNight
8%13%6%9%9%5%6%5%6%7%20%
2865
16th to endNight
10%12%49%8%45%46%7%26%
2939
February1st to 15thNight
7%10%5%9%7%46%5%5%8%28%
2452
16th to endNight
5%9%5%9%8%47%6%6%8%27%
2054
March1st to 15thNight
9%11%47%6%46%5%6%8%29%
2160
16th to endNight
8%12%36%5%46%6%6%8%33%
2015
April1st to 15thNight
9%9%46%6%45%46%6%34%
1730
16th to endNight
10%10%47%5%5%6%5%6%7%30%
1488
May1st to 15thNight
10%5%26%6%46%45%7%39%
1310
16th to endNight
12%5%46%6%35%5%7%8%34%
1176
June1st to 15thNight
12%5%36%6%46%6%7%8%32%
1080
16th to endNight
13%5%246%345%6%8%39%
1080
July1st to 15thNight
11%415%5%25%6%7%8%40%
1080
16th to endNight
9%325%6%35%6%7%9%40%
1164
August1st to 15thNight
7%324426%5%8%8%46%
1416
16th to endNight
11%5%25%5%35%48%7%39%
1609
September1st to 15thNight
10%425%5%35%5%5%8%43%
1779
16th to endNight
10%7%25%5%345%6%9%38%
1811
October1st to 15thNight
11%9%38%6%345%6%7%32%
2024
16th to endNight
12%12%47%7%45%5%46%30%
2292
November1st to 15thNight
11%12%47%6%25%5%5%6%30%
2596
16th to endNight
6%11%7%11%9%5%7%5%5%7%23%
2715
December1st to 15thNight
10%14%6%11%10%46%5%5%7%18%
2880
16th to endNight
5%12%6%11%8%5%6%5%6%9%21%
3072

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
62%6%16%9%4
1074
16th to endDay
54%5%18%15%41
1296
February1st to 15thDay
54%5%17%16%5%
1400
16th to endDay
57%6%16%16%3
1419
March1st to 15thDay
54%6%17%16%4
1800
16th to endDay
51%6%17%19%4
2202
April1st to 15thDay
48%416%21%7%1
2218
16th to endDay
52%5%12%21%8%
2469
May1st to 15thDay
42%6%15%22%12%
2639
16th to endDay
45%412%24%11%1
2940
June1st to 15thDay
51%5%15%21%5%
2880
16th to endDay
46%6%16%24%6%
2880
July1st to 15thDay
41%7%20%23%5%
2711
16th to endDay
38%8%26%22%3
2816
August1st to 15thDay
39%9%25%20%3
2524
16th to endDay
42%8%23%21%3
2593
September1st to 15thDay
39%6%26%23%3
2180
16th to endDay
41%7%21%21%7%
1838
October1st to 15thDay
53%5%16%21%3
1603
16th to endDay
55%6%19%16%1
1579
November1st to 15thDay
53%6%16%20%2
1249
16th to endDay
59%6%15%14%31
1242
December1st to 15thDay
66%7%11%11%3
1080
16th to endDay
60%8%11%16%2
1152
January1st to 15thNight
61%7%15%12%3
2865
16th to endNight
56%5%15%15%5%1
2939
February1st to 15thNight
52%6%16%17%6%
2464
16th to endNight
51%5%20%17%5%
2054
March1st to 15thNight
50%5%15%22%6%
2160
16th to endNight
46%415%23%9%
2019
April1st to 15thNight
48%410%23%12%2
1730
16th to endNight
50%412%21%10%
1488
May1st to 15thNight
43%49%24%17%1
1311
16th to endNight
43%414%22%11%2
1176
June1st to 15thNight
46%5%15%24%7%
1080
16th to endNight
42%317%26%8%
1080
July1st to 15thNight
37%6%21%25%8%
1020
16th to endNight
35%8%27%24%3
1090
August1st to 15thNight
29%9%28%25%6%
1409
16th to endNight
39%5%23%23%7%
1609
September1st to 15thNight
36%6%22%25%8%
1779
16th to endNight
41%6%18%24%8%
1811
October1st to 15thNight
49%7%17%21%4
2024
16th to endNight
53%6%18%18%3
2292
November1st to 15thNight
51%6%15%22%3
2596
16th to endNight
58%8%15%14%2
2715
December1st to 15thNight
65%6%12%13%2
2880
16th to endNight
58%5%15%17%2
3072

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
11%5%20%25%31%6%
60
16th to endDay
20%114%34%25%4
64
February1st to 15thDay
23%18%30%18%10%
60
16th to endDay
10%418%37%19%9%
153
March1st to 15thDay
13%426%32%17%4
270
16th to endDay
17%220%33%20%6%
288
April1st to 15thDay
13%6%23%32%20%3
269
16th to endDay
15%14%25%22%15%6%
270
May1st to 15thDay
12%8%22%26%22%6%
416
16th to endDay
13%6%15%29%27%6%
651
June1st to 15thDay
16%6%18%27%23%6%
675
16th to endDay
15%5%16%28%23%11%
675
July1st to 15thDay
11%418%31%27%6%
645
16th to endDay
10%417%31%24%9%
673
August1st to 15thDay
10%415%27%29%13%
337
16th to endDay
15%10%26%32%11%2
332
September1st to 15thDay
16%6%18%28%19%10%
315
16th to endDay
11%13%28%28%14%3
258
October1st to 15thDay
21%8%20%27%18%3
186
16th to endDay
21%113%31%25%7%
95
November1st to 15thDay
15%340%25%16%
60
16th to endDay
11%321%33%25%5%
60
December1st to 15thDay
11%313%35%23%13%
60
16th to endDay
9%6%14%43%21%4
64
January1st to 15thNight
13%5%24%36%17%3
930
16th to endNight
17%6%22%37%14%1
909
February1st to 15thNight
12%319%39%20%4
704
16th to endNight
9%218%39%25%4
632
March1st to 15thNight
14%5%24%36%16%2
720
16th to endNight
13%316%40%23%2
768
April1st to 15thNight
12%417%38%24%2
650
16th to endNight
14%322%34%21%3
408
May1st to 15thNight
13%5%18%33%26%2
360
16th to endNight
14%315%37%26%2
375
June1st to 15thNight
15%311%36%31%1
360
16th to endNight
15%111%36%29%4
360
July1st to 15thNight
12%212%37%31%2
340
16th to endNight
10%312%32%36%3
376
August1st to 15thNight
6%18%32%41%9%
360
16th to endNight
12%115%43%22%3
463
September1st to 15thNight
13%212%36%30%4
699
16th to endNight
13%5%23%35%18%4
660
October1st to 15thNight
14%6%20%37%17%3
660
16th to endNight
19%6%16%38%16%2
704
November1st to 15thNight
15%7%25%36%13%1
846
16th to endNight
12%7%22%39%14%2
903
December1st to 15thNight
17%6%22%35%14%3
930
16th to endNight
12%420%37%21%4
992
Page generated at 2017-09-17 10:05:46. Version ac04

Copyright 2017 A. Danko


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