Estevan
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Estevan 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
38%
25176
15%
80317
9%
25093
44%
25093
23%
52814

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
29%
938
13%
4377
6%
926
36%
926
12%
3012
January11th to 20thNight
25%
945
9%
4399
5%
930
30%
930
10%
3229
January21st to endNight
25%
1036
9%
4729
5%
1023
31%
1023
10%
3177
February1st to 10thNight
31%
923
12%
2583
5%
923
37%
923
17%
1927
February11th to 20thNight
31%
709
13%
2228
9%
709
37%
709
17%
1614
February21st to endNight
43%
592
19%
1776
12%
592
49%
592
24%
1199
March1st to 10thNight
32%
720
10%
2160
6%
720
35%
720
17%
1597
March11th to 20thNight
37%
694
18%
2126
11%
694
45%
694
23%
1424
March21st to endNight
37%
594
15%
1980
12%
594
42%
594
19%
1347
April1st to 10thNight
38%
540
20%
1800
14%
540
49%
540
29%
1071
April11th to 20thNight
29%
533
14%
1717
10%
533
36%
533
18%
1194
April21st to endNight
36%
540
15%
1591
10%
540
42%
540
24%
1075
May1st to 10thNight
47%
540
18%
1440
9%
540
50%
540
33%
906
May11th to 20thNight
48%
531
15%
1418
7%
531
50%
531
31%
908
May21st to endNight
43%
584
11%
1467
5%
582
46%
582
29%
1006
June1st to 10thNight
48%
540
10%
1260
5%
540
51%
540
37%
820
June11th to 20thNight
44%
540
6%
1260
5%
540
45%
540
34%
848
June21st to endNight
54%
540
9%
1260
6%
540
57%
540
39%
812
July1st to 10thNight
61%
525
10%
1285
7%
525
63%
525
50%
740
July11th to 20thNight
57%
522
13%
1392
8%
522
60%
522
44%
796
July21st to endNight
57%
591
20%
1488
9%
558
63%
558
54%
778
August1st to 10thNight
62%
537
19%
1424
10%
534
67%
534
45%
810
August11th to 20thNight
61%
534
25%
1468
17%
534
67%
534
46%
811
August21st to endNight
56%
594
27%
1924
24%
594
64%
594
44%
950
September1st to 10thNight
52%
540
24%
1800
21%
540
61%
540
37%
944
September11th to 20thNight
49%
540
23%
1872
21%
540
57%
540
32%
1024
September21st to endNight
43%
540
23%
1980
19%
540
54%
540
25%
1159
October1st to 10thNight
44%
652
20%
2092
14%
652
50%
652
27%
1290
October11th to 20thNight
40%
818
21%
2258
10%
818
47%
818
29%
1451
October21st to endNight
33%
990
19%
2574
7%
990
40%
990
26%
1762
November1st to 10thNight
31%
925
17%
2405
6%
925
37%
925
22%
1717
November11th to 20thNight
28%
950
16%
2646
8%
950
34%
950
20%
1914
November21st to endNight
29%
950
13%
2845
6%
950
36%
950
19%
2002
December1st to 10thNight
28%
950
10%
2850
5%
950
34%
950
16%
2098
December11th to 20thNight
24%
949
12%
3441
5%
948
32%
948
12%
2567
December21st to endNight
28%
1030
9%
5002
6%
1026
35%
1026
11%
2835

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%47%6%45%5%5%7%38%
77882
Night
8%8%48%7%45%5%6%7%38%
81012
TransparencyDay
45%5%15%25%10%1
77582
Night
45%5%15%24%11%1
80834
SeeingDay
14%8%29%29%16%4
15060
Night
13%7%31%35%13%1
25222

By Month

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 10thDay
7%11%5%11%11%6%9%6%6%6%22%
2518
11th to 20thDay
48%5%13%11%8%10%10%7%6%17%
2540
21st to endDay
6%10%5%12%9%5%5%5%6%6%33%
2794
February1st to 10thDay
9%11%6%10%9%5%7%7%6%6%25%
1478
11th to 20thDay
7%14%5%10%9%6%7%6%7%7%21%
1629
21st to endDay
6%11%6%12%10%5%5%6%6%8%26%
1480
March1st to 10thDay
10%14%7%12%10%35%6%5%6%22%
1800
11th to 20thDay
9%11%5%8%7%445%5%7%34%
1833
21st to endDay
11%11%5%10%7%45%5%6%8%28%
2376
April1st to 10thDay
8%8%47%6%446%6%8%40%
2160
11th to 20thDay
14%13%47%7%25%5%5%8%30%
2191
21st to endDay
14%9%37%5%25%45%7%37%
2366
May1st to 10thDay
14%8%36%435%5%5%7%41%
2520
11th to 20thDay
13%6%26%5%35%5%6%8%41%
2478
21st to endDay
20%6%36%6%35%5%5%7%33%
2806
June1st to 10thDay
13%5%25%5%35%5%6%10%41%
2700
11th to 20thDay
15%6%35%6%35%5%6%8%37%
2700
21st to endDay
11%5%245%35%5%6%9%44%
2700
July1st to 10thDay
7%324435%5%5%9%53%
2632
11th to 20thDay
6%4245%35%5%6%8%54%
2520
21st to endDay
5%4144345%6%8%56%
2742
August1st to 10thDay
8%424435%5%5%8%50%
2507
11th to 20thDay
8%424435%5%5%9%51%
2433
21st to endDay
10%41443445%7%54%
2430
September1st to 10thDay
12%5%234335%5%7%51%
2160
11th to 20thDay
14%6%25%43345%6%48%
2088
21st to endDay
16%5%24424448%48%
1980
October1st to 10thDay
17%9%36%42335%7%40%
1865
11th to 20thDay
11%9%5%7%5%3435%7%42%
1683
21st to endDay
13%10%49%6%35%5%5%7%33%
1782
November1st to 10thDay
13%13%6%6%6%45%5%5%5%32%
1673
11th to 20thDay
8%11%6%11%6%445%46%34%
1530
21st to endDay
10%13%6%9%7%36%5%5%7%28%
1333
December1st to 10thDay
9%14%5%12%9%36%5%6%7%25%
1330
11th to 20thDay
7%16%7%12%7%5%5%6%5%9%20%
1683
21st to endDay
6%7%46%6%35%6%5%6%45%
2442
January1st to 10thNight
5%12%6%10%10%45%6%6%7%28%
4421
11th to 20thNight
47%5%13%11%6%9%9%7%6%22%
4430
21st to endNight
7%11%49%9%46%6%6%8%29%
4873
February1st to 10thNight
8%11%5%10%9%5%6%8%7%8%25%
2583
11th to 20thNight
7%13%5%11%8%46%6%7%7%27%
2227
21st to endNight
6%8%5%10%8%45%5%6%8%35%
1776
March1st to 10thNight
7%10%6%11%10%45%5%5%6%29%
2160
11th to 20thNight
8%9%48%7%445%7%7%36%
2126
21st to endNight
9%10%5%8%7%45%5%7%8%32%
1980
April1st to 10thNight
6%8%46%5%345%6%9%44%
1800
11th to 20thNight
13%13%47%6%445%5%7%31%
1717
21st to endNight
13%8%46%6%35%47%6%38%
1591
May1st to 10thNight
11%7%35%5%35%5%6%6%45%
1440
11th to 20thNight
12%5%35%5%4446%8%43%
1417
21st to endNight
18%6%24435%5%6%9%38%
1467
June1st to 10thNight
13%424325%5%8%10%43%
1260
11th to 20thNight
11%435%4445%6%9%44%
1260
21st to endNight
10%4145%35%5%6%9%49%
1260
July1st to 10thNight
5%323425%46%10%57%
1323
11th to 20thNight
7%314425%447%59%
1440
21st to endNight
322342346%7%64%
1576
August1st to 10thNight
5%3144345%6%7%57%
1432
11th to 20thNight
7%2134345%6%8%58%
1468
21st to endNight
8%313324447%62%
1924
September1st to 10thNight
10%41432445%7%56%
1800
11th to 20thNight
11%41443346%7%52%
1872
21st to endNight
13%6%26%433347%46%
1980
October1st to 10thNight
14%9%35%42335%7%46%
2092
11th to 20thNight
12%8%36%5%2346%6%44%
2258
21st to endNight
11%10%47%5%245%5%8%38%
2574
November1st to 10thNight
12%12%47%6%345%5%7%35%
2405
11th to 20thNight
8%10%5%9%10%5%5%5%5%7%32%
2646
21st to endNight
7%10%5%10%7%45%45%7%34%
2845
December1st to 10thNight
7%13%5%11%9%46%6%5%7%27%
2850
11th to 20thNight
8%13%6%11%8%5%6%6%6%6%25%
3514
21st to endNight
6%8%48%7%45%6%6%8%39%
5225

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
62%5%15%14%3
2519
11th to 20thDay
66%413%12%4
2540
21st to endDay
52%414%26%4
2794
February1st to 10thDay
59%413%17%7%
1478
11th to 20thDay
61%5%10%14%9%
1638
21st to endDay
55%5%14%18%8%1
1480
March1st to 10thDay
62%7%14%13%4
1800
11th to 20thDay
49%6%16%22%7%
1833
21st to endDay
54%5%16%19%5%1
2376
April1st to 10thDay
41%6%15%24%13%1
2160
11th to 20thDay
53%414%18%9%1
2194
21st to endDay
47%416%24%8%
2366
May1st to 10thDay
42%412%28%12%2
2520
11th to 20thDay
40%5%14%28%13%
2482
21st to endDay
51%5%13%20%11%1
2806
June1st to 10thDay
38%5%18%27%10%1
2700
11th to 20thDay
44%5%16%24%9%1
2700
21st to endDay
36%6%19%29%8%1
2700
July1st to 10thDay
27%5%20%34%12%1
2561
11th to 20thDay
28%6%16%31%17%2
2445
21st to endDay
25%6%14%35%19%1
2590
August1st to 10thDay
31%6%17%31%13%2
2491
11th to 20thDay
30%5%18%32%14%1
2433
21st to endDay
30%412%37%17%1
2430
September1st to 10thDay
32%414%31%17%2
2160
11th to 20thDay
37%5%14%27%15%2
2088
21st to endDay
36%411%33%15%1
1980
October1st to 10thDay
45%413%27%10%1
1865
11th to 20thDay
43%315%28%11%1
1683
21st to endDay
50%6%16%21%7%1
1782
November1st to 10thDay
54%5%12%21%7%1
1673
11th to 20thDay
52%419%16%9%1
1530
21st to endDay
56%6%18%14%5%1
1333
December1st to 10thDay
59%414%18%5%
1330
11th to 20thDay
61%5%17%14%3
1680
21st to endDay
38%412%29%15%1
2442
January1st to 10thNight
54%5%15%20%6%
4421
11th to 20thNight
60%5%16%15%4
4430
21st to endNight
52%6%18%20%4
4873
February1st to 10thNight
54%6%12%20%8%
2583
11th to 20thNight
54%5%14%17%9%1
2228
21st to endNight
46%415%23%11%1
1776
March1st to 10thNight
56%5%16%17%6%
2160
11th to 20thNight
46%414%26%8%1
2126
21st to endNight
49%5%17%21%7%1
1980
April1st to 10thNight
36%5%14%25%19%2
1800
11th to 20thNight
52%410%22%11%1
1717
21st to endNight
47%412%26%10%1
1591
May1st to 10thNight
37%413%27%17%2
1440
11th to 20thNight
39%5%13%27%17%
1418
21st to endNight
41%7%14%26%11%1
1467
June1st to 10thNight
34%6%17%28%13%2
1260
11th to 20thNight
38%5%20%21%14%2
1260
21st to endNight
32%7%18%33%10%1
1260
July1st to 10thNight
23%5%19%37%14%2
1285
11th to 20thNight
26%6%16%33%17%3
1392
21st to endNight
20%415%38%21%3
1488
August1st to 10thNight
25%5%20%31%16%3
1424
11th to 20thNight
23%6%16%37%16%2
1468
21st to endNight
23%412%34%25%3
1924
September1st to 10thNight
27%5%10%32%24%2
1800
11th to 20thNight
32%5%16%27%19%2
1872
21st to endNight
38%411%31%14%2
1980
October1st to 10thNight
40%415%26%13%2
2092
11th to 20thNight
41%313%29%12%1
2258
21st to endNight
45%416%26%8%1
2574
November1st to 10thNight
49%5%13%20%10%2
2405
11th to 20thNight
53%417%19%7%1
2646
21st to endNight
50%5%18%20%6%
2845
December1st to 10thNight
55%5%16%17%6%
2850
11th to 20thNight
58%5%15%16%5%1
3516
21st to endNight
42%5%12%23%15%3
5225

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
13%6%33%30%12%6%
270
11th to 20thDay
10%8%37%33%10%3
270
21st to endDay
12%10%30%34%13%1
297
February1st to 10thDay
12%7%38%33%10%1
252
11th to 20thDay
16%438%30%10%2
240
21st to endDay
7%432%36%19%3
198
March1st to 10thDay
16%8%37%27%11%2
240
11th to 20thDay
15%7%34%28%12%4
247
21st to endDay
16%11%31%29%10%3
462
April1st to 10thDay
11%16%39%26%7%2
420
11th to 20thDay
21%12%31%25%10%2
472
21st to endDay
16%10%29%31%13%2
600
May1st to 10thDay
15%7%29%29%17%3
603
11th to 20thDay
16%7%27%28%16%6%
625
21st to endDay
19%7%24%24%21%5%
679
June1st to 10thDay
12%9%27%28%18%6%
630
11th to 20thDay
14%10%34%26%13%3
630
21st to endDay
11%6%26%32%20%6%
630
July1st to 10thDay
9%5%21%38%23%5%
621
11th to 20thDay
9%7%28%33%18%4
618
21st to endDay
5%6%27%33%22%8%
684
August1st to 10thDay
11%423%34%22%7%
626
11th to 20thDay
11%5%23%31%24%6%
615
21st to endDay
11%6%22%34%21%6%
549
September1st to 10thDay
14%10%28%30%14%3
450
11th to 20thDay
18%10%26%29%16%2
378
21st to endDay
24%5%28%27%15%2
270
October1st to 10thDay
22%8%25%27%16%2
270
11th to 20thDay
14%12%30%26%14%5%
270
21st to endDay
22%10%34%24%9%1
297
November1st to 10thDay
24%7%29%23%13%3
270
11th to 20thDay
13%11%34%30%10%1
270
21st to endDay
16%10%35%27%11%1
270
December1st to 10thDay
14%8%37%26%11%4
270
11th to 20thDay
13%11%43%26%7%1
270
21st to endDay
10%6%36%25%17%5%
297
January1st to 10thNight
10%10%36%31%11%1
950
11th to 20thNight
13%12%32%33%9%1
950
21st to endNight
12%9%37%31%10%1
1045
February1st to 10thNight
11%8%33%33%13%1
923
11th to 20thNight
13%6%35%33%10%3
713
21st to endNight
8%5%26%39%18%4
592
March1st to 10thNight
13%8%32%33%12%3
720
11th to 20thNight
13%6%34%35%11%1
694
21st to endNight
15%5%32%34%13%1
594
April1st to 10thNight
11%7%35%36%11%
540
11th to 20thNight
19%8%34%30%8%
533
21st to endNight
18%5%34%31%11%1
540
May1st to 10thNight
14%7%24%41%13%1
540
11th to 20thNight
15%6%24%40%15%
531
21st to endNight
20%5%25%34%16%1
584
June1st to 10thNight
16%426%36%17%1
540
11th to 20thNight
15%6%30%36%13%
540
21st to endNight
11%425%43%17%1
540
July1st to 10thNight
6%324%47%19%1
525
11th to 20thNight
8%228%46%14%1
522
21st to endNight
3231%42%20%1
591
August1st to 10thNight
7%322%49%16%2
537
11th to 20thNight
7%323%43%23%1
534
21st to endNight
10%327%41%18%1
594
September1st to 10thNight
13%426%38%17%1
540
11th to 20thNight
12%429%39%16%1
540
21st to endNight
15%6%28%39%11%1
540
October1st to 10thNight
17%8%25%34%15%1
652
11th to 20thNight
17%8%25%34%14%1
818
21st to endNight
17%9%31%32%10%1
990
November1st to 10thNight
18%9%33%30%10%1
925
11th to 20thNight
14%9%36%30%10%2
950
21st to endNight
13%10%36%31%9%
950
December1st to 10thNight
13%7%35%32%11%3
950
11th to 20thNight
15%11%33%30%9%2
950
21st to endNight
15%6%32%32%13%1
1045
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