Regina
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Regina clear sky chart from 2005-11-06 to 2024-03-28.

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%
24739
13%
80928
8%
24656
43%
24656
20%
53922

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
32%
937
10%
4688
5%
926
39%
926
11%
3298
January11th to 20thNight
28%
947
8%
4410
5%
930
32%
930
9%
3360
January21st to endNight
25%
1033
7%
4812
4%
1023
30%
1023
9%
3134
February1st to 10thNight
31%
926
12%
2636
5%
926
38%
926
16%
1983
February11th to 20thNight
33%
740
13%
2403
8%
740
39%
740
17%
1695
February21st to endNight
45%
628
16%
1916
11%
628
49%
628
21%
1337
March1st to 10thNight
33%
760
11%
2280
7%
760
38%
760
19%
1657
March11th to 20thNight
37%
760
17%
2195
10%
760
44%
760
23%
1505
March21st to endNight
40%
644
12%
2079
10%
644
44%
644
17%
1477
April1st to 10thNight
40%
540
17%
1800
13%
540
48%
540
27%
1084
April11th to 20thNight
33%
533
13%
1751
9%
533
39%
533
19%
1192
April21st to endNight
35%
540
14%
1476
8%
540
40%
540
22%
1049
May1st to 10thNight
46%
540
15%
1440
7%
540
49%
540
31%
944
May11th to 20thNight
44%
531
13%
1418
7%
531
46%
531
31%
903
May21st to endNight
41%
584
8%
1485
4%
582
44%
582
25%
1038
June1st to 10thNight
45%
450
7%
1170
4%
450
49%
450
34%
737
June11th to 20thNight
42%
360
4%
1080
4%
360
45%
360
25%
711
June21st to endNight
52%
360
4%
1080
5%
360
54%
360
31%
656
July1st to 10thNight
55%
350
6%
1118
5%
350
59%
350
38%
595
July11th to 20thNight
54%
437
10%
1307
6%
437
59%
437
40%
725
July21st to endNight
59%
591
16%
1488
9%
558
63%
558
51%
791
August1st to 10thNight
57%
537
17%
1424
10%
534
61%
534
43%
826
August11th to 20thNight
63%
534
22%
1424
14%
534
68%
534
44%
821
August21st to endNight
55%
594
25%
1925
20%
594
63%
594
39%
1011
September1st to 10thNight
50%
540
20%
1800
19%
540
58%
540
31%
1022
September11th to 20thNight
51%
540
21%
1815
20%
540
58%
540
30%
1046
September21st to endNight
44%
558
22%
1998
17%
558
55%
558
27%
1133
October1st to 10thNight
43%
720
17%
2160
11%
720
47%
720
26%
1402
October11th to 20thNight
43%
778
21%
2218
12%
778
49%
778
30%
1387
October21st to endNight
33%
990
16%
2574
6%
990
38%
990
21%
1880
November1st to 10thNight
28%
925
13%
2511
5%
925
34%
925
18%
1898
November11th to 20thNight
30%
950
12%
2660
6%
950
35%
950
17%
2001
November21st to endNight
28%
950
11%
2816
5%
950
34%
950
18%
2031
December1st to 10thNight
28%
950
10%
2850
5%
950
33%
950
15%
2167
December11th to 20thNight
25%
950
10%
3496
4%
949
31%
949
9%
2683
December21st to endNight
31%
1032
8%
5225
6%
1026
37%
1026
11%
2743

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%46%5%6%7%37%
78350
Night
8%8%48%7%46%5%6%7%36%
81602
TransparencyDay
45%7%16%23%9%1
78066
Night
45%7%15%22%10%1
81466
SeeingDay
13%9%30%30%15%3
15066
Night
13%7%31%35%13%1
24784

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 10thDay
7%12%5%12%9%5%8%8%6%7%20%
2219
11th to 20thDay
5%7%410%12%7%12%11%9%7%17%
2489
21st to endDay
6%11%6%11%7%5%7%5%5%6%32%
2794
February1st to 10thDay
8%12%7%13%9%6%8%6%5%7%20%
1562
11th to 20thDay
8%12%5%9%8%5%10%8%7%5%24%
1665
21st to endDay
6%9%6%12%13%5%8%7%7%6%23%
1537
March1st to 10thDay
9%12%7%12%10%48%5%6%7%20%
1900
11th to 20thDay
6%12%6%8%6%45%5%6%8%33%
1983
21st to endDay
8%10%5%11%7%45%6%6%9%30%
2432
April1st to 10thDay
7%7%47%6%45%5%8%9%37%
2160
11th to 20thDay
14%13%49%7%35%5%6%7%28%
2160
21st to endDay
14%10%46%6%36%5%5%7%36%
2481
May1st to 10thDay
11%7%36%6%446%6%8%40%
2520
11th to 20thDay
9%7%36%6%45%5%6%8%40%
2478
21st to endDay
19%7%36%5%45%5%6%9%31%
2790
June1st to 10thDay
15%446%6%35%5%6%9%37%
2785
11th to 20thDay
19%7%36%6%46%5%5%7%33%
2880
21st to endDay
11%5%25%5%45%6%7%9%42%
2880
July1st to 10thDay
7%324435%5%6%10%50%
2804
11th to 20thDay
9%324445%6%6%8%50%
2610
21st to endDay
6%214435%5%5%8%56%
2742
August1st to 10thDay
8%3245%35%5%6%8%51%
2507
11th to 20thDay
9%4245%2446%8%50%
2477
21st to endDay
10%5%25%435%447%52%
2427
September1st to 10thDay
11%5%35%43446%7%48%
2160
11th to 20thDay
12%8%35%5%3445%8%45%
2144
21st to endDay
13%5%3442445%8%48%
1959
October1st to 10thDay
15%10%36%5%3445%7%38%
1800
11th to 20thDay
10%9%47%5%3446%6%42%
1724
21st to endDay
10%11%7%10%7%3445%6%32%
1782
November1st to 10thDay
13%14%5%8%8%3445%5%30%
1565
11th to 20thDay
7%10%6%12%9%6%6%46%7%28%
1520
21st to endDay
10%11%6%9%7%5%6%6%6%7%28%
1361
December1st to 10thDay
8%11%6%14%10%48%6%6%6%21%
1330
11th to 20thDay
7%14%7%13%9%5%6%7%6%6%19%
1633
21st to endDay
5%7%5%7%7%45%5%46%45%
2090
January1st to 10thNight
412%6%11%10%46%6%7%8%26%
4726
11th to 20thNight
47%412%12%8%12%8%6%5%21%
4414
21st to endNight
6%11%5%9%6%6%6%6%6%7%32%
4873
February1st to 10thNight
8%10%6%10%8%5%8%7%7%8%24%
2636
11th to 20thNight
6%10%410%8%48%6%7%8%27%
2402
21st to endNight
5%7%411%9%5%7%5%6%9%31%
1916
March1st to 10thNight
8%9%5%11%9%45%6%5%8%29%
2280
11th to 20thNight
6%11%5%7%8%45%6%6%8%35%
2195
21st to endNight
10%9%5%10%8%46%6%6%7%30%
2079
April1st to 10thNight
7%8%36%5%45%5%8%7%43%
1800
11th to 20thNight
13%11%47%5%445%6%8%33%
1751
21st to endNight
13%8%47%6%45%6%6%8%33%
1476
May1st to 10thNight
12%7%35%5%345%6%8%40%
1440
11th to 20thNight
10%6%35%6%35%46%8%44%
1418
21st to endNight
16%6%35%5%45%5%6%9%37%
1485
June1st to 10thNight
12%4245%346%7%8%46%
1170
11th to 20thNight
16%6%35%435%5%6%8%41%
1080
21st to endNight
9%435%5%445%7%11%45%
1080
July1st to 10thNight
7%3144335%6%9%55%
1152
11th to 20thNight
7%42443445%9%55%
1350
21st to endNight
5%31233345%8%62%
1576
August1st to 10thNight
7%3134246%6%7%57%
1432
11th to 20thNight
6%4134345%6%11%53%
1424
21st to endNight
8%414423447%58%
1925
September1st to 10thNight
10%4245%345%5%7%52%
1800
11th to 20thNight
10%5%25%4435%5%8%49%
1815
21st to endNight
11%5%35%43346%6%49%
1998
October1st to 10thNight
13%8%46%43445%9%40%
2160
11th to 20thNight
8%8%36%5%3445%7%47%
2218
21st to endNight
10%12%49%7%45%5%5%6%33%
2574
November1st to 10thNight
15%12%5%8%7%35%446%31%
2511
11th to 20thNight
8%11%5%11%9%5%6%5%5%7%28%
2660
21st to endNight
8%11%6%10%7%35%5%5%8%32%
2816
December1st to 10thNight
8%11%5%12%11%5%7%5%6%6%26%
2850
11th to 20thNight
8%12%6%13%9%5%6%6%5%6%24%
3558
21st to endNight
5%7%37%6%35%6%7%7%43%
5562

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
61%8%14%12%4
2219
11th to 20thDay
59%8%17%11%4
2513
21st to endDay
52%6%15%22%4
2794
February1st to 10thDay
62%7%11%15%6%
1562
11th to 20thDay
58%6%11%14%10%1
1674
21st to endDay
57%8%13%13%8%
1537
March1st to 10thDay
62%8%12%15%4
1900
11th to 20thDay
47%7%20%19%7%
1984
21st to endDay
50%9%17%18%6%
2432
April1st to 10thDay
41%8%18%22%11%1
2160
11th to 20thDay
55%7%13%18%6%2
2160
21st to endDay
48%5%17%21%7%1
2481
May1st to 10thDay
41%6%14%26%12%1
2520
11th to 20thDay
39%8%13%28%12%1
2482
21st to endDay
49%7%14%19%10%1
2790
June1st to 10thDay
42%7%16%26%8%1
2785
11th to 20thDay
50%8%13%19%10%1
2880
21st to endDay
36%10%18%27%9%1
2880
July1st to 10thDay
27%9%22%31%11%1
2729
11th to 20thDay
31%9%19%27%13%1
2530
21st to endDay
24%8%16%37%13%1
2590
August1st to 10thDay
29%8%22%28%11%1
2491
11th to 20thDay
31%8%19%31%11%1
2477
21st to endDay
31%7%12%33%15%1
2427
September1st to 10thDay
34%6%15%28%15%2
2160
11th to 20thDay
39%5%14%28%12%2
2144
21st to endDay
34%6%15%31%12%1
1959
October1st to 10thDay
45%6%15%24%8%1
1800
11th to 20thDay
41%6%13%30%10%1
1724
21st to endDay
52%6%17%18%6%
1782
November1st to 10thDay
56%7%15%15%7%
1565
11th to 20thDay
55%7%14%16%7%1
1520
21st to endDay
55%9%17%16%4
1361
December1st to 10thDay
61%6%12%14%6%
1330
11th to 20thDay
62%9%16%10%3
1634
21st to endDay
39%5%12%24%13%7%
2090
January1st to 10thNight
53%8%17%17%4
4726
11th to 20thNight
61%7%16%13%3
4452
21st to endNight
50%8%17%21%4
4873
February1st to 10thNight
56%6%13%18%7%
2636
11th to 20thNight
51%7%14%18%10%1
2403
21st to endNight
48%7%16%21%8%
1916
March1st to 10thNight
52%6%18%18%6%
2280
11th to 20thNight
45%6%17%24%7%1
2195
21st to endNight
51%7%15%17%9%
2079
April1st to 10thNight
37%6%14%26%17%1
1800
11th to 20thNight
49%5%12%21%10%3
1751
21st to endNight
46%8%11%24%10%1
1476
May1st to 10thNight
40%5%13%24%17%2
1440
11th to 20thNight
37%6%12%27%17%2
1418
21st to endNight
42%9%15%20%14%1
1485
June1st to 10thNight
34%7%16%29%14%1
1170
11th to 20thNight
40%8%18%19%13%1
1080
21st to endNight
33%8%19%29%10%1
1080
July1st to 10thNight
24%8%21%34%12%1
1118
11th to 20thNight
26%7%17%31%16%2
1307
21st to endNight
19%6%17%39%17%2
1488
August1st to 10thNight
24%9%19%33%14%1
1424
11th to 20thNight
25%7%18%34%14%2
1424
21st to endNight
25%6%12%35%20%2
1925
September1st to 10thNight
31%7%11%28%21%2
1800
11th to 20thNight
33%7%15%27%17%1
1815
21st to endNight
34%6%13%30%15%2
1998
October1st to 10thNight
41%6%18%25%9%1
2160
11th to 20thNight
37%6%17%28%12%1
2218
21st to endNight
50%6%13%23%7%1
2574
November1st to 10thNight
54%7%13%17%7%1
2511
11th to 20thNight
54%7%18%14%5%
2660
21st to endNight
51%7%19%19%4
2816
December1st to 10thNight
59%5%15%16%5%
2850
11th to 20thNight
60%7%13%15%5%1
3556
21st to endNight
36%7%13%23%16%5%
5562

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
11%8%37%23%17%4
180
11th to 20thDay
9%9%33%34%13%2
264
21st to endDay
13%9%35%30%12%1
297
February1st to 10thDay
15%8%38%28%10%1
270
11th to 20thDay
13%9%33%29%14%2
270
21st to endDay
8%5%33%38%16%1
225
March1st to 10thDay
13%7%37%29%11%3
270
11th to 20thDay
11%11%38%28%9%4
354
21st to endDay
13%13%31%27%14%1
491
April1st to 10thDay
9%17%37%30%6%2
420
11th to 20thDay
20%12%30%26%11%1
438
21st to endDay
16%10%29%29%15%1
600
May1st to 10thDay
12%8%30%29%19%2
603
11th to 20thDay
13%9%25%30%15%7%
625
21st to endDay
17%9%23%28%17%6%
679
June1st to 10thDay
14%11%29%25%17%4
630
11th to 20thDay
19%13%30%23%13%2
630
21st to endDay
11%6%26%31%22%3
630
July1st to 10thDay
8%5%24%38%20%5%
621
11th to 20thDay
8%8%30%30%19%6%
618
21st to endDay
6%8%27%30%20%9%
684
August1st to 10thDay
10%5%22%37%20%6%
626
11th to 20thDay
9%5%21%34%24%6%
615
21st to endDay
11%8%22%33%22%4
502
September1st to 10thDay
14%12%31%28%13%2
450
11th to 20thDay
17%9%29%29%15%2
434
21st to endDay
14%8%33%31%11%2
270
October1st to 10thDay
19%9%28%25%16%3
270
11th to 20thDay
11%12%34%27%13%2
270
21st to endDay
15%13%38%25%6%3
297
November1st to 10thDay
20%8%31%26%13%2
270
11th to 20thDay
12%9%42%30%6%
270
21st to endDay
12%10%37%30%10%1
270
December1st to 10thDay
12%8%34%33%11%2
270
11th to 20thDay
12%9%49%22%8%
255
21st to endDay
12%7%35%33%11%3
198
January1st to 10thNight
8%11%35%33%11%2
950
11th to 20thNight
13%10%33%36%7%1
950
21st to endNight
10%11%38%31%10%1
1045
February1st to 10thNight
12%6%34%34%12%2
926
11th to 20thNight
9%7%35%37%10%2
744
21st to endNight
6%6%26%39%20%4
628
March1st to 10thNight
12%7%35%33%12%1
760
11th to 20thNight
10%8%35%33%13%1
760
21st to endNight
13%6%30%36%14%1
644
April1st to 10thNight
11%9%32%34%12%1
540
11th to 20thNight
19%8%32%34%7%1
533
21st to endNight
18%8%31%36%6%
540
May1st to 10thNight
15%7%26%38%13%1
540
11th to 20thNight
13%7%28%34%16%1
531
21st to endNight
19%5%26%33%15%2
584
June1st to 10thNight
13%5%29%35%16%1
450
11th to 20thNight
21%5%25%38%10%1
360
21st to endNight
13%6%22%41%18%1
360
July1st to 10thNight
9%129%40%19%1
350
11th to 20thNight
8%428%43%17%
437
21st to endNight
6%426%42%20%2
591
August1st to 10thNight
7%426%40%21%2
537
11th to 20thNight
6%420%42%26%2
534
21st to endNight
11%425%39%20%1
594
September1st to 10thNight
11%6%27%35%19%2
540
11th to 20thNight
14%6%25%40%15%1
540
21st to endNight
11%8%30%41%10%1
558
October1st to 10thNight
19%5%25%35%15%1
720
11th to 20thNight
13%6%28%38%13%1
778
21st to endNight
17%9%30%34%9%1
990
November1st to 10thNight
21%8%32%30%8%1
925
11th to 20thNight
14%10%33%31%10%1
950
21st to endNight
13%9%38%32%6%1
950
December1st to 10thNight
12%7%36%31%12%3
950
11th to 20thNight
12%12%33%32%10%1
950
21st to endNight
12%5%34%34%13%2
1045
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