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 2018-04-23.

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%
16089
10%
49563
8%
16064
49%
16064
19%
35015

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
37%
1016
7%
3105
5%
1015
39%
1015
13%
2420
January16th to endNight
35%
994
12%
3184
9%
994
38%
994
14%
2357
February1st to 15thNight
46%
756
11%
2674
12%
756
49%
756
16%
1890
February16th to endNight
51%
684
11%
2223
12%
684
53%
684
19%
1580
March1st to 15thNight
45%
780
15%
2340
12%
780
48%
780
21%
1646
March16th to endNight
51%
831
14%
2188
9%
831
52%
831
24%
1554
April1st to 15thNight
51%
704
15%
1874
9%
704
54%
704
26%
1301
April16th to endNight
43%
422
10%
1538
12%
422
47%
422
17%
1048
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
51%
716
16%
1965
10%
716
55%
716
28%
1304
October1st to 15thNight
45%
720
12%
2208
8%
720
49%
720
20%
1560
October16th to endNight
40%
768
13%
2501
10%
768
46%
768
16%
1775
November1st to 15thNight
37%
919
12%
2819
9%
919
41%
919
17%
2049
November16th to endNight
38%
980
7%
2942
5%
980
40%
980
13%
2305
December1st to 15thNight
34%
1020
7%
3120
5%
1020
36%
1020
11%
2480
December16th to endNight
39%
1088
11%
3328
7%
1088
43%
1088
15%
2502

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%
50013
Night
9%9%48%7%45%5%6%7%30%
49687
TransparencyDay
48%6%18%20%5%
49642
Night
50%6%16%20%6%
49563
SeeingDay
13%6%19%30%22%7%
7549
Night
13%418%37%21%3
16104

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
9%13%6%8%11%38%5%5%7%20%
1164
16th to endDay
8%12%38%7%5%5%5%5%6%29%
1404
February1st to 15thDay
8%10%410%7%47%7%6%8%23%
1520
16th to endDay
5%10%5%11%10%6%7%6%6%8%21%
1536
March1st to 15thDay
6%12%6%8%8%46%5%5%7%28%
1950
16th to endDay
9%13%5%8%6%35%5%5%8%28%
2385
April1st to 15thDay
7%9%45%7%5%5%45%7%35%
2404
16th to endDay
11%10%5%8%6%45%447%31%
2532
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%6%35%5%3447%8%37%
1995
October1st to 15thDay
15%9%47%6%35%45%6%31%
1749
16th to endDay
13%11%5%8%6%35%46%7%27%
1722
November1st to 15thDay
10%11%6%8%6%36%5%6%7%27%
1355
16th to endDay
7%13%6%11%7%5%7%45%6%22%
1345
December1st to 15thDay
11%13%5%10%11%5%7%45%8%17%
1170
16th to endDay
6%11%6%10%10%5%6%6%6%7%21%
1248
January1st to 15thNight
8%13%6%9%9%46%5%6%7%21%
3105
16th to endNight
11%12%49%8%45%45%6%25%
3184
February1st to 15thNight
6%11%6%9%7%46%5%5%7%28%
2662
16th to endNight
5%9%5%9%9%47%6%6%8%28%
2223
March1st to 15thNight
8%11%47%6%45%5%6%8%30%
2340
16th to endNight
8%11%46%5%46%6%6%7%31%
2184
April1st to 15thNight
9%9%36%6%45%5%6%6%36%
1874
16th to endNight
10%10%47%5%5%6%5%6%6%30%
1538
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%39%
1965
October1st to 15thNight
11%9%38%6%345%6%7%33%
2208
16th to endNight
13%12%36%6%445%46%31%
2501
November1st to 15thNight
11%12%47%7%25%5%5%6%29%
2819
16th to endNight
6%11%6%11%9%5%7%5%5%7%22%
2942
December1st to 15thNight
10%13%6%11%9%45%5%47%21%
3120
16th to endNight
5%12%6%11%9%5%6%5%6%9%22%
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
61%6%16%11%4
1164
16th to endDay
55%5%17%15%41
1404
February1st to 15thDay
54%5%17%15%5%
1520
16th to endDay
57%6%16%15%3
1536
March1st to 15thDay
53%6%17%18%4
1950
16th to endDay
53%6%16%19%4
2385
April1st to 15thDay
46%416%23%7%
2404
16th to endDay
52%5%12%21%7%
2532
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
42%8%21%20%7%
1995
October1st to 15thDay
52%5%17%20%4
1749
16th to endDay
54%6%20%16%2
1722
November1st to 15thDay
54%6%16%19%2
1355
16th to endDay
59%6%15%14%21
1345
December1st to 15thDay
65%7%11%12%4
1170
16th to endDay
59%7%10%16%4
1248
January1st to 15thNight
60%7%15%12%4
3105
16th to endNight
57%5%14%15%41
3184
February1st to 15thNight
53%5%16%18%6%
2674
16th to endNight
51%6%20%17%4
2223
March1st to 15thNight
49%5%14%23%6%
2340
16th to endNight
48%415%22%8%
2188
April1st to 15thNight
46%49%25%12%1
1874
16th to endNight
51%412%21%10%
1538
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
40%6%19%24%8%
1965
October1st to 15thNight
48%6%17%21%4
2208
16th to endNight
52%6%17%19%4
2501
November1st to 15thNight
52%6%15%21%3
2819
16th to endNight
58%8%15%14%2
2942
December1st to 15thNight
62%6%12%14%3
3120
16th to endNight
57%5%14%16%5%
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
12%320%24%31%8%
90
16th to endDay
17%113%33%29%5%
96
February1st to 15thDay
17%20%33%22%6%
90
16th to endDay
9%317%36%22%9%
192
March1st to 15thDay
12%323%33%20%6%
330
16th to endDay
18%221%30%21%6%
352
April1st to 15thDay
11%5%22%32%21%6%
329
16th to endDay
15%13%26%24%14%5%
288
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
12%11%25%26%19%5%
315
October1st to 15thDay
20%9%20%27%17%5%
240
16th to endDay
19%122%33%18%4
142
November1st to 15thDay
13%233%26%22%2
90
16th to endDay
12%422%36%21%3
90
December1st to 15thDay
8%6%11%37%26%8%
90
16th to endDay
7%5%12%39%28%7%
96
January1st to 15thNight
13%5%23%35%19%3
1020
16th to endNight
17%6%21%37%15%1
994
February1st to 15thNight
12%318%41%19%4
764
16th to endNight
9%217%40%26%3
684
March1st to 15thNight
13%423%36%18%2
780
16th to endNight
14%316%39%23%3
832
April1st to 15thNight
12%316%39%25%3
704
16th to endNight
14%422%34%20%3
422
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%421%36%19%4
716
October1st to 15thNight
14%6%21%36%17%3
720
16th to endNight
19%6%17%38%16%2
768
November1st to 15thNight
15%6%23%37%14%2
919
16th to endNight
13%7%22%39%14%2
980
December1st to 15thNight
16%6%21%36%15%3
1020
16th to endNight
11%419%38%21%3
1088
Page generated at 2018-04-24 08:02:59. Version ac04

Copyright 2018 A. Danko


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