Assiniboia
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Assiniboia clear sky chart from 2005-11-05 to 2017-09-10.

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
38%
15756
14%
46737
8%
15718
43%
15718
23%
31361

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
27%
895
10%
2667
4%
895
31%
895
18%
1901
January16th to endNight
24%
960
13%
2688
6%
960
31%
960
17%
1989
February1st to 15thNight
31%
747
9%
2339
6%
747
36%
747
16%
1707
February16th to endNight
35%
632
12%
1998
8%
632
40%
632
16%
1478
March1st to 15thNight
34%
720
14%
2122
7%
720
40%
720
21%
1487
March16th to endNight
31%
684
12%
2028
7%
684
36%
684
16%
1503
April1st to 15thNight
39%
539
15%
1798
10%
539
45%
539
24%
1142
April16th to endNight
39%
540
15%
1582
10%
540
43%
540
23%
1092
May1st to 15thNight
45%
540
14%
1440
8%
540
49%
540
32%
928
May16th to endNight
41%
563
8%
1498
5%
561
43%
561
22%
1081
June1st to 15thNight
42%
399
5%
1299
3%
399
45%
399
27%
793
June16th to endNight
53%
360
6%
1260
6%
360
56%
360
30%
717
July1st to 15thNight
58%
340
7%
1190
7%
340
61%
340
36%
619
July16th to endNight
62%
541
16%
1393
9%
508
65%
508
50%
733
August1st to 15thNight
65%
539
18%
1432
13%
536
69%
536
46%
813
August16th to endNight
63%
573
27%
1795
21%
573
70%
573
45%
908
September1st to 15thNight
58%
525
19%
1750
18%
525
63%
525
32%
999
September16th to endNight
51%
541
25%
1792
21%
541
59%
541
33%
992
October1st to 15thNight
40%
660
21%
1980
12%
660
48%
660
30%
1218
October16th to endNight
35%
823
19%
2231
8%
823
43%
823
26%
1514
November1st to 15thNight
30%
875
17%
2422
7%
875
37%
875
24%
1659
November16th to endNight
23%
900
15%
2520
5%
900
32%
900
19%
1830
December1st to 15thNight
26%
900
8%
2633
4%
900
30%
900
12%
2099
December16th to endNight
26%
960
12%
2880
5%
960
33%
960
15%
2159

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%8%36%6%35%5%5%7%37%
47906
Night
8%8%46%6%35%45%7%38%
46895
Cloud CoverDay
11%7%36%5%35%45%7%37%
47907
Night
9%8%46%6%35%45%7%38%
46897
TransparencyDay
45%6%16%22%8%
47568
Night
44%5%15%22%10%1
46737
SeeingDay
14%7%27%29%17%4
6147
Night
13%7%31%33%12%1
15769

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
6%11%6%10%7%47%6%46%26%
1270
16th to endDay
410%5%11%7%47%6%7%8%25%
1536
February1st to 15thDay
8%12%7%11%9%5%8%43424%
1535
16th to endDay
6%14%6%11%8%47%5%5%6%22%
1476
March1st to 15thDay
7%10%5%11%8%446%6%9%24%
1836
16th to endDay
9%12%5%9%6%35%47%10%24%
2194
April1st to 15thDay
11%9%36%5%36%5%6%7%33%
2150
16th to endDay
17%10%46%4245%5%6%31%
2376
May1st to 15thDay
13%8%35%6%25%5%47%36%
2511
16th to endDay
20%6%36%6%35%46%7%30%
2616
June1st to 15thDay
18%6%35%6%35%5%5%7%33%
2658
16th to endDay
10%5%246%35%6%6%8%39%
2700
July1st to 15thDay
6%314435%5%7%8%49%
2700
16th to endDay
5%22442445%9%55%
2679
August1st to 15thDay
8%5%145%35%5%5%7%47%
2520
16th to endDay
8%313323448%55%
2405
September1st to 15thDay
12%6%24423445%48%
2097
16th to endDay
13%42422325%8%50%
1837
October1st to 15thDay
16%8%35%423346%41%
1650
16th to endDay
11%9%36%5%2446%8%37%
1629
November1st to 15thDay
8%9%47%6%1445%7%40%
1435
16th to endDay
10%10%5%8%6%35%46%6%31%
1440
December1st to 15thDay
7%14%6%12%10%5%5%6%5%5%17%
1322
16th to endDay
7%12%7%11%8%5%6%6%5%5%23%
1334
January1st to 15thNight
6%12%5%7%6%46%6%6%7%31%
2667
16th to endNight
5%11%5%9%7%46%5%7%9%27%
2688
February1st to 15thNight
7%12%6%9%6%5%5%5%5%6%29%
2328
16th to endNight
7%12%6%9%8%45%46%6%27%
1998
March1st to 15thNight
5%8%5%7%9%45%5%5%9%32%
2122
16th to endNight
10%12%5%9%6%36%45%7%27%
2025
April1st to 15thNight
8%7%36%6%3445%9%39%
1798
16th to endNight
12%9%36%3346%6%8%33%
1582
May1st to 15thNight
11%7%25%42346%8%42%
1439
16th to endNight
18%5%25%5%26%5%7%7%32%
1498
June1st to 15thNight
14%42332445%9%43%
1299
16th to endNight
7%425%325%5%5%8%48%
1260
July1st to 15thNight
5%414315%45%9%52%
1260
16th to endNight
422242346%7%59%
1488
August1st to 15thNight
6%313332449%56%
1440
16th to endNight
7%313322345%63%
1795
September1st to 15thNight
9%4145%24446%51%
1750
16th to endNight
11%313424447%53%
1792
October1st to 15thNight
12%7%24413347%48%
1980
16th to endNight
9%10%35%5%35%5%6%7%37%
2231
November1st to 15thNight
9%10%46%6%2445%5%39%
2422
16th to endNight
8%11%5%9%6%35%448%31%
2520
December1st to 15thNight
8%14%6%10%9%5%6%5%5%6%21%
2633
16th to endNight
6%11%5%10%9%46%5%5%7%26%
2880

Percentage Cloud Cover SW (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
6%11%7%10%7%47%5%5%7%27%
1270
16th to endDay
49%6%10%8%38%6%6%8%26%
1536
February1st to 15thDay
9%11%8%10%9%5%8%43424%
1535
16th to endDay
7%13%7%12%7%46%6%5%6%22%
1476
March1st to 15thDay
7%11%6%11%8%45%5%7%8%24%
1836
16th to endDay
10%11%5%8%6%45%46%10%25%
2195
April1st to 15thDay
12%8%36%5%36%5%5%7%34%
2150
16th to endDay
18%10%36%4345%5%7%31%
2376
May1st to 15thDay
14%8%245%245%5%7%37%
2511
16th to endDay
21%6%35%6%35%45%7%31%
2616
June1st to 15thDay
20%5%25%6%345%5%7%33%
2658
16th to endDay
11%5%25%5%35%5%6%8%40%
2700
July1st to 15thDay
6%314435%5%6%8%50%
2700
16th to endDay
6%21432445%7%56%
2679
August1st to 15thDay
9%4145%35%45%7%47%
2520
16th to endDay
9%31332335%8%55%
2405
September1st to 15thDay
12%6%24423436%49%
2097
16th to endDay
14%42431335%7%50%
1837
October1st to 15thDay
16%8%35%423346%42%
1650
16th to endDay
12%8%36%42446%7%38%
1629
November1st to 15thDay
9%9%36%5%2445%7%39%
1435
16th to endDay
10%11%5%7%7%45%46%6%31%
1440
December1st to 15thDay
7%14%7%12%11%5%6%5%5%5%17%
1322
16th to endDay
8%12%6%11%8%5%7%5%5%6%22%
1334
January1st to 15thNight
6%12%5%7%6%46%6%6%6%31%
2667
16th to endNight
5%11%5%9%7%46%5%7%8%28%
2688
February1st to 15thNight
7%11%6%8%7%5%5%5%46%29%
2328
16th to endNight
7%13%5%10%7%45%45%6%28%
1998
March1st to 15thNight
6%9%47%8%46%5%5%9%33%
2122
16th to endNight
11%12%5%9%6%46%45%6%28%
2028
April1st to 15thNight
9%7%36%5%3446%8%40%
1798
16th to endNight
13%9%36%4246%6%8%34%
1582
May1st to 15thNight
12%6%35%42436%9%43%
1439
16th to endNight
19%5%245%35%46%8%32%
1497
June1st to 15thNight
15%5%233245%5%9%43%
1299
16th to endNight
8%4243246%5%9%48%
1260
July1st to 15thNight
6%414325%46%8%53%
1260
16th to endNight
421232346%7%60%
1488
August1st to 15thNight
8%21332246%8%57%
1440
16th to endNight
7%312312346%63%
1795
September1st to 15thNight
9%4145%34446%51%
1750
16th to endNight
11%313423446%54%
1792
October1st to 15thNight
13%7%24313246%48%
1980
16th to endNight
9%9%45%5%345%6%7%38%
2231
November1st to 15thNight
10%10%46%5%3435%5%39%
2422
16th to endNight
8%12%49%6%45%448%31%
2520
December1st to 15thNight
9%14%6%10%9%46%5%5%6%21%
2633
16th to endNight
7%11%5%9%9%46%5%47%26%
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
56%7%11%19%5%
1270
16th to endDay
51%8%18%16%4
1536
February1st to 15thDay
63%410%14%6%
1535
16th to endDay
60%6%13%12%6%
1476
March1st to 15thDay
54%8%17%16%2
1836
16th to endDay
53%6%20%14%3
2195
April1st to 15thDay
47%7%17%19%7%
2150
16th to endDay
50%5%16%19%6%1
2376
May1st to 15thDay
45%414%26%9%
2511
16th to endDay
51%6%13%20%7%
2620
June1st to 15thDay
48%7%16%20%7%
2658
16th to endDay
39%6%18%27%6%
2700
July1st to 15thDay
28%6%19%30%13%
2541
16th to endDay
25%6%15%31%18%2
2511
August1st to 15thDay
35%5%17%28%11%2
2504
16th to endDay
27%414%34%15%3
2405
September1st to 15thDay
36%5%14%26%15%2
2097
16th to endDay
33%413%32%14%1
1837
October1st to 15thDay
44%416%26%8%
1650
16th to endDay
43%5%20%24%5%
1629
November1st to 15thDay
43%5%17%22%9%1
1435
16th to endDay
52%7%18%16%5%
1440
December1st to 15thDay
65%8%13%11%1
1322
16th to endDay
59%7%18%12%2
1334
January1st to 15thNight
49%7%19%18%4
2667
16th to endNight
51%7%17%16%5%1
2688
February1st to 15thNight
54%5%16%16%7%
2339
16th to endNight
55%6%13%17%7%
1998
March1st to 15thNight
47%6%17%22%6%
2122
16th to endNight
56%415%17%4
2028
April1st to 15thNight
41%5%16%24%10%1
1798
16th to endNight
45%7%14%19%11%1
1582
May1st to 15thNight
38%414%28%14%
1440
16th to endNight
47%7%13%20%10%
1498
June1st to 15thNight
37%6%17%24%13%1
1299
16th to endNight
31%7%19%32%8%
1260
July1st to 15thNight
26%6%16%33%14%1
1190
16th to endNight
20%417%34%19%4
1393
August1st to 15thNight
24%5%17%34%16%1
1432
16th to endNight
22%411%30%25%4
1795
September1st to 15thNight
33%411%26%19%3
1750
16th to endNight
31%411%31%19%1
1792
October1st to 15thNight
37%417%25%14%1
1980
16th to endNight
43%5%16%25%8%1
2231
November1st to 15thNight
45%416%20%10%2
2422
16th to endNight
51%5%18%17%6%
2520
December1st to 15thNight
62%6%13%14%3
2633
16th to endNight
55%6%16%16%5%
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
11%23%33%25%6%
63
16th to endDay
11%11%29%21%20%5%
96
February1st to 15thDay
16%8%41%31%2
90
16th to endDay
17%443%18%13%2
81
March1st to 15thDay
19%11%34%22%9%2
126
16th to endDay
16%11%39%20%9%1
288
April1st to 15thDay
14%16%35%26%5%
269
16th to endDay
24%8%23%30%12%1
363
May1st to 15thDay
16%7%26%28%16%4
468
16th to endDay
20%8%21%24%17%7%
517
June1st to 15thDay
16%10%27%26%14%3
495
16th to endDay
11%8%27%31%17%3
495
July1st to 15thDay
7%323%36%23%5%
475
16th to endDay
6%326%36%23%2
515
August1st to 15thDay
11%321%31%24%7%
493
16th to endDay
11%5%20%33%22%6%
335
September1st to 15thDay
15%7%25%30%17%3
294
16th to endDay
16%7%20%33%16%5%
162
October1st to 15thDay
33%327%18%13%3
90
16th to endDay
18%6%22%34%12%5%
96
November1st to 15thDay
12%6%37%25%14%3
90
16th to endDay
15%12%22%32%17%
90
December1st to 15thDay
16%5%37%21%12%6%
90
16th to endDay
18%9%45%12%15%
66
January1st to 15thNight
10%12%38%27%10%
900
16th to endNight
11%12%39%27%7%1
960
February1st to 15thNight
12%9%30%30%14%2
755
16th to endNight
12%7%28%33%15%4
632
March1st to 15thNight
9%9%33%32%13%2
720
16th to endNight
16%7%31%34%9%
684
April1st to 15thNight
12%8%31%36%10%
539
16th to endNight
18%6%28%36%9%
540
May1st to 15thNight
15%6%25%37%13%1
540
16th to endNight
21%7%22%30%15%1
563
June1st to 15thNight
15%8%27%36%11%1
399
16th to endNight
13%5%23%39%17%
360
July1st to 15thNight
8%225%42%19%1
340
16th to endNight
5%326%47%16%1
541
August1st to 15thNight
8%119%43%23%2
539
16th to endNight
8%220%43%22%1
573
September1st to 15thNight
9%320%44%18%2
525
16th to endNight
12%426%40%14%1
541
October1st to 15thNight
17%5%30%30%14%2
660
16th to endNight
15%6%33%33%10%
823
November1st to 15thNight
16%8%37%26%9%1
875
16th to endNight
14%9%42%26%6%
900
December1st to 15thNight
16%7%33%28%11%1
900
16th to endNight
12%9%34%28%12%2
960
Page generated at 2017-09-11 17:35:31. Version ac04

Copyright 2017 A. Danko


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