Battle River
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Battle River clear sky chart from 2005-11-05 to

2017-09-12
.

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
40%
15294
10%
46705
7%
15269
44%
15269
19%
33219

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
33%
895
7%
2685
3%
895
36%
895
13%
2088
January16th to endNight
28%
957
13%
2877
6%
957
35%
957
16%
2107
February1st to 15thNight
39%
696
8%
2365
6%
696
44%
696
15%
1726
February16th to endNight
42%
632
12%
2052
11%
632
47%
632
17%
1495
March1st to 15thNight
37%
720
12%
2088
8%
720
41%
720
18%
1546
March16th to endNight
36%
768
9%
2111
5%
767
39%
767
17%
1622
April1st to 15thNight
38%
548
12%
1682
7%
548
42%
548
18%
1199
April16th to endNight
41%
540
14%
1590
11%
540
44%
540
21%
1112
May1st to 15thNight
46%
463
9%
1363
6%
463
48%
463
22%
926
May16th to endNight
45%
374
2%
1309
2%
374
45%
374
17%
891
June1st to 15thNight
41%
360
0%
1260
0%
360
41%
360
15%
901
June16th to endNight
50%
360
0%
1260
0%
360
50%
360
18%
841
July1st to 15thNight
60%
340
0%
1190
0%
340
60%
340
26%
698
July16th to endNight
59%
376
4%
1239
3%
354
60%
354
28%
721
August1st to 15thNight
64%
441
7%
1403
7%
439
65%
439
25%
894
August16th to endNight
58%
573
15%
1719
13%
573
60%
573
32%
1046
September1st to 15thNight
56%
544
13%
1723
11%
544
58%
544
29%
1054
September16th to endNight
55%
656
19%
1818
12%
656
62%
656
38%
1080
October1st to 15thNight
43%
660
16%
1980
10%
660
49%
660
22%
1363
October16th to endNight
37%
756
15%
2309
10%
756
42%
756
20%
1614
November1st to 15thNight
35%
875
14%
2450
9%
875
40%
875
18%
1815
November16th to endNight
30%
900
10%
2652
5%
900
34%
900
15%
2022
December1st to 15thNight
27%
900
7%
2700
3%
900
30%
900
10%
2190
December16th to endNight
31%
960
9%
2880
4%
960
36%
960
13%
2268

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
12%9%47%6%35%5%6%7%31%
47998
Night
9%9%48%7%45%5%5%7%31%
46857
TransparencyDay
49%8%17%18%5%
47648
Night
49%7%16%19%6%
46711
SeeingDay
16%6%25%29%16%5%
6118
Night
13%5%27%34%16%2
15309

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%10%6%9%8%6%6%5%6%6%22%
1253
16th to endDay
6%13%6%8%10%35%5%5%6%27%
1359
February1st to 15thDay
8%12%7%10%9%45%45%7%25%
1494
16th to endDay
7%14%7%13%8%35%6%6%6%18%
1422
March1st to 15thDay
9%13%5%8%9%46%6%6%7%22%
1872
16th to endDay
13%14%6%9%8%3445%6%23%
2111
April1st to 15thDay
11%12%5%8%7%35%5%5%6%29%
2266
16th to endDay
17%12%46%43445%8%29%
2370
May1st to 15thDay
11%8%36%6%35%5%6%6%34%
2586
16th to endDay
17%8%25%6%45%5%7%7%29%
2802
June1st to 15thDay
17%7%37%7%46%5%7%6%25%
2700
16th to endDay
17%7%25%6%36%6%7%8%27%
2700
July1st to 15thDay
11%5%245%35%6%7%9%39%
2700
16th to endDay
9%425%5%35%5%7%9%40%
2846
August1st to 15thDay
12%5%26%6%45%6%5%8%36%
2549
16th to endDay
9%5%244245%6%9%43%
2483
September1st to 15thDay
12%7%25%5%34436%44%
2156
16th to endDay
11%41443445%8%47%
1812
October1st to 15thDay
13%11%46%5%25%5%35%35%
1650
16th to endDay
9%11%46%6%245%5%8%34%
1550
November1st to 15thDay
11%10%5%7%7%345%5%8%29%
1408
16th to endDay
8%11%8%10%7%46%36%8%24%
1305
December1st to 15thDay
9%15%7%10%8%5%8%6%5%5%16%
1260
16th to endDay
6%13%6%11%9%7%8%5%5%7%18%
1344
January1st to 15thNight
8%11%5%8%9%6%6%7%7%6%22%
2685
16th to endNight
5%11%5%9%8%46%45%7%29%
2877
February1st to 15thNight
6%10%411%8%47%5%6%6%27%
2358
16th to endNight
7%11%5%10%7%46%5%5%9%26%
2052
March1st to 15thNight
9%7%5%9%8%5%6%5%5%9%27%
2088
16th to endNight
11%13%6%9%7%345%5%6%26%
2109
April1st to 15thNight
10%10%46%6%35%6%6%6%31%
1682
16th to endNight
14%10%27%43445%7%35%
1590
May1st to 15thNight
11%7%35%6%36%6%5%7%35%
1363
16th to endNight
18%6%25%5%36%5%5%7%32%
1309
June1st to 15thNight
13%10%48%6%35%5%6%7%28%
1260
16th to endNight
14%5%35%5%36%6%6%7%35%
1260
July1st to 15thNight
7%424435%6%6%10%43%
1260
16th to endNight
7%325%5%25%5%7%11%44%
1323
August1st to 15thNight
9%4245%446%7%10%40%
1410
16th to endNight
6%5%26%5%345%6%9%46%
1719
September1st to 15thNight
12%6%15%434437%47%
1723
16th to endNight
8%41333346%8%53%
1818
October1st to 15thNight
11%10%36%43445%8%35%
1980
16th to endNight
11%11%45%5%35%5%6%8%32%
2309
November1st to 15thNight
12%11%47%6%35%45%6%30%
2450
16th to endNight
8%10%6%11%7%46%446%28%
2652
December1st to 15thNight
9%14%7%11%9%5%6%5%5%7%18%
2700
16th to endNight
411%6%11%11%6%7%6%5%6%21%
2880

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
58%9%14%13%4
1253
16th to endDay
56%7%11%15%7%1
1359
February1st to 15thDay
57%6%14%16%4
1494
16th to endDay
62%8%10%12%5%
1422
March1st to 15thDay
58%8%17%12%3
1872
16th to endDay
60%7%12%15%4
2112
April1st to 15thDay
54%6%15%17%5%1
2266
16th to endDay
53%6%14%17%6%1
2370
May1st to 15thDay
47%7%12%21%9%
2586
16th to endDay
50%9%14%16%8%
2807
June1st to 15thDay
54%8%14%15%4
2700
16th to endDay
49%10%20%15%3
2700
July1st to 15thDay
38%10%24%22%3
2541
16th to endDay
37%11%25%22%2
2667
August1st to 15thDay
43%12%23%18%3
2531
16th to endDay
35%9%22%26%5%
2483
September1st to 15thDay
40%7%18%23%8%2
2156
16th to endDay
34%8%17%30%7%1
1812
October1st to 15thDay
48%6%16%23%4
1650
16th to endDay
45%8%17%22%6%
1550
November1st to 15thDay
51%7%17%19%4
1408
16th to endDay
56%8%17%13%3
1305
December1st to 15thDay
66%8%10%12%1
1260
16th to endDay
63%6%11%13%4
1344
January1st to 15thNight
57%9%15%13%4
2685
16th to endNight
52%7%15%17%6%1
2877
February1st to 15thNight
53%6%16%15%6%
2369
16th to endNight
52%7%14%17%7%
2052
March1st to 15thNight
51%8%16%17%5%
2088
16th to endNight
56%6%13%17%5%
2112
April1st to 15thNight
49%7%15%17%8%1
1682
16th to endNight
48%6%12%17%12%2
1590
May1st to 15thNight
45%7%9%25%11%
1364
16th to endNight
48%6%14%20%6%2
1309
June1st to 15thNight
51%8%16%17%5%
1260
16th to endNight
44%9%19%19%6%
1260
July1st to 15thNight
33%9%24%25%7%
1190
16th to endNight
32%9%25%26%6%
1239
August1st to 15thNight
35%11%25%22%3
1403
16th to endNight
32%7%19%29%9%
1719
September1st to 15thNight
36%6%18%23%10%4
1723
16th to endNight
28%7%18%33%10%2
1818
October1st to 15thNight
45%7%14%24%8%
1980
16th to endNight
47%7%17%22%4
2309
November1st to 15thNight
53%6%14%18%6%1
2450
16th to endNight
56%7%17%13%5%
2652
December1st to 15thNight
65%6%13%11%2
2700
16th to endNight
59%7%15%13%3
2880

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%321%38%21%1
60
16th to endDay
14%6%20%39%15%4
64
February1st to 15thDay
11%5%28%32%16%5%
77
16th to endDay
28%229%17%19%2
81
March1st to 15thDay
16%5%40%29%6%1
240
16th to endDay
23%8%31%26%10%
288
April1st to 15thDay
19%9%33%26%8%1
269
16th to endDay
26%10%18%28%14%2
300
May1st to 15thDay
13%10%24%32%15%5%
468
16th to endDay
19%7%21%25%16%8%
517
June1st to 15thDay
18%7%26%27%14%5%
495
16th to endDay
16%7%23%28%17%7%
495
July1st to 15thDay
13%319%33%24%6%
475
16th to endDay
12%423%31%24%4
515
August1st to 15thDay
12%314%32%27%9%
423
16th to endDay
10%425%32%22%3
332
September1st to 15thDay
18%6%30%26%14%4
300
16th to endDay
16%9%26%30%13%3
252
October1st to 15thDay
26%7%24%31%7%2
90
16th to endDay
13%6%31%28%17%3
96
November1st to 15thDay
18%328%41%6%1
90
16th to endDay
16%7%31%25%5%13%
67
December1st to 15thDay
16%328%30%11%10%
60
16th to endDay
15%329%29%18%3
64
January1st to 15thNight
13%5%31%34%13%1
900
16th to endNight
11%8%35%33%9%1
957
February1st to 15thNight
10%5%25%39%16%2
704
16th to endNight
11%325%36%18%4
632
March1st to 15thNight
11%432%35%13%2
720
16th to endNight
14%431%30%16%2
768
April1st to 15thNight
14%7%27%35%12%2
548
16th to endNight
18%6%24%33%15%1
540
May1st to 15thNight
14%5%23%36%17%1
464
16th to endNight
20%5%22%28%20%2
375
June1st to 15thNight
20%423%32%16%2
360
16th to endNight
17%222%30%24%1
360
July1st to 15thNight
11%319%38%25%
340
16th to endNight
6%421%43%21%2
376
August1st to 15thNight
11%213%37%28%6%
441
16th to endNight
8%221%41%23%1
573
September1st to 15thNight
16%317%39%21%1
544
16th to endNight
9%5%26%38%18%1
656
October1st to 15thNight
16%427%32%17%2
660
16th to endNight
17%429%35%11%
756
November1st to 15thNight
18%5%30%32%10%2
875
16th to endNight
12%7%33%32%11%2
900
December1st to 15thNight
14%8%29%27%15%3
900
16th to endNight
10%430%35%16%3
960
Page generated at 2017-09-13 05:39:08. Version ac04

Copyright 2017 A. Danko


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