Rosetown
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rosetown clear sky chart from 2005-11-06 to 2024-01-14.

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
41%
23958
13%
74629
8%
23927
46%
23927
22%
49428

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
35%
946
10%
2836
5%
946
39%
946
17%
2058
January11th to 20thNight
30%
918
12%
2752
6%
918
37%
918
16%
2010
January21st to endNight
28%
990
10%
2912
4%
990
34%
990
13%
2260
February1st to 10thNight
36%
774
12%
2394
9%
774
41%
774
16%
1753
February11th to 20thNight
36%
700
12%
2273
9%
700
41%
700
16%
1648
February21st to endNight
51%
592
16%
1924
13%
592
56%
592
22%
1302
March1st to 10thNight
39%
720
12%
2133
8%
720
43%
720
20%
1547
March11th to 20thNight
44%
720
17%
1980
10%
720
49%
720
24%
1367
March21st to endNight
39%
726
12%
2112
8%
726
43%
726
20%
1527
April1st to 10thNight
43%
540
17%
1800
12%
540
49%
540
25%
1115
April11th to 20thNight
35%
533
13%
1643
7%
533
39%
533
19%
1161
April21st to endNight
39%
540
13%
1512
10%
540
43%
540
21%
1078
May1st to 10thNight
48%
540
13%
1440
9%
540
50%
540
31%
948
May11th to 20thNight
50%
531
12%
1418
7%
531
52%
531
33%
892
May21st to endNight
48%
388
7%
1358
6%
388
51%
388
22%
864
June1st to 10thNight
48%
360
2%
1238
2%
360
49%
360
24%
748
June11th to 20thNight
43%
360
0%
1080
0%
360
43%
360
19%
778
June21st to endNight
60%
360
0%
1195
0%
360
60%
360
30%
683
July1st to 10thNight
62%
350
1%
1225
1%
350
62%
350
32%
673
July11th to 20thNight
55%
348
6%
1218
5%
348
59%
348
33%
654
July21st to endNight
67%
420
15%
1327
13%
397
71%
397
45%
631
August1st to 10thNight
65%
537
16%
1424
12%
534
68%
534
45%
804
August11th to 20thNight
65%
534
17%
1540
14%
534
67%
534
38%
910
August21st to endNight
58%
594
24%
1804
18%
594
63%
594
38%
1011
September1st to 10thNight
53%
540
18%
1800
16%
540
57%
540
31%
1027
September11th to 20thNight
54%
540
20%
1800
19%
540
59%
540
29%
1067
September21st to endNight
48%
713
24%
2061
16%
713
56%
713
38%
1192
October1st to 10thNight
42%
720
19%
2160
12%
720
49%
720
27%
1400
October11th to 20thNight
44%
720
23%
2160
13%
720
51%
720
31%
1288
October21st to endNight
33%
949
16%
2623
6%
949
40%
949
21%
1862
November1st to 10thNight
31%
925
15%
2590
7%
925
37%
925
17%
1939
November11th to 20thNight
33%
950
13%
2660
6%
950
39%
950
17%
1968
November21st to endNight
28%
950
11%
2660
5%
950
33%
950
18%
1966
December1st to 10thNight
32%
950
10%
2979
5%
950
37%
950
16%
2210
December11th to 20thNight
28%
950
10%
3702
4%
949
34%
949
11%
2738
December21st to endNight
35%
1030
9%
4896
6%
1026
42%
1026
16%
2349

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%6%8%37%
74559
Night
8%8%47%7%45%5%6%8%38%
75183
TransparencyDay
44%8%15%23%9%1
74242
Night
43%7%15%23%10%1
75019
SeeingDay
12%8%27%30%18%5%
14551
Night
12%6%29%36%15%2
23982

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%11%8%5%5%6%6%8%27%
1329
11th to 20thDay
7%10%6%12%9%46%7%7%7%25%
1281
21st to endDay
5%14%7%10%8%47%8%7%7%22%
1443
February1st to 10thDay
8%11%6%13%8%6%7%5%5%7%23%
1581
11th to 20thDay
7%12%5%10%8%5%7%5%7%7%28%
1575
21st to endDay
6%10%5%10%10%6%8%7%7%8%24%
1332
March1st to 10thDay
8%10%6%11%10%5%9%5%6%7%22%
1822
11th to 20thDay
7%10%5%11%7%5%6%6%6%8%29%
1979
21st to endDay
9%11%6%9%9%35%5%6%9%28%
2243
April1st to 10thDay
9%9%49%6%5%6%6%7%7%34%
2160
11th to 20thDay
10%13%5%9%7%35%7%5%8%29%
2265
21st to endDay
14%9%46%6%45%45%8%34%
2448
May1st to 10thDay
13%6%27%7%5%5%5%6%8%35%
2520
11th to 20thDay
9%6%36%6%45%6%7%8%40%
2478
21st to endDay
17%7%36%6%35%5%5%7%35%
2914
June1st to 10thDay
13%8%36%6%46%5%6%8%37%
2718
11th to 20thDay
20%7%36%7%45%5%6%7%30%
2880
21st to endDay
9%426%6%46%6%7%9%39%
2756
July1st to 10thDay
6%325%5%36%6%7%10%46%
2700
11th to 20thDay
10%3235%346%6%9%48%
2700
21st to endDay
6%3144245%6%9%55%
2912
August1st to 10thDay
9%424435%5%7%9%47%
2507
11th to 20thDay
9%5%34445%5%6%8%47%
2360
21st to endDay
11%425%42445%9%49%
2552
September1st to 10thDay
10%6%25%5%3446%8%48%
2160
11th to 20thDay
13%7%36%5%2345%7%45%
2160
21st to endDay
10%5%2443345%8%52%
1896
October1st to 10thDay
13%9%26%6%34447%42%
1800
11th to 20thDay
9%7%46%5%45%46%8%42%
1800
21st to endDay
8%10%49%6%46%6%6%8%33%
1712
November1st to 10thDay
12%14%5%9%8%435%4432%
1488
11th to 20thDay
7%12%7%12%8%5%5%6%5%6%28%
1520
21st to endDay
9%11%7%9%9%46%5%5%6%28%
1520
December1st to 10thDay
8%10%5%10%9%6%7%7%8%9%23%
1196
11th to 20thDay
7%11%410%8%5%7%5%6%6%28%
1439
21st to endDay
38%47%6%35%6%6%8%43%
2413
January1st to 10thNight
5%10%5%9%8%6%7%7%7%9%27%
2836
11th to 20thNight
6%10%6%10%8%5%7%6%5%8%30%
2752
21st to endNight
6%13%6%10%9%5%6%7%7%9%22%
2912
February1st to 10thNight
7%11%6%11%7%47%6%7%8%26%
2394
11th to 20thNight
6%11%5%10%9%5%8%6%6%8%27%
2272
21st to endNight
38%6%8%8%5%7%7%7%10%31%
1924
March1st to 10thNight
7%10%6%10%8%47%7%6%8%29%
2133
11th to 20thNight
7%9%37%6%46%5%7%9%36%
1980
21st to endNight
8%10%5%9%7%36%6%7%10%29%
2112
April1st to 10thNight
6%9%36%6%445%6%9%41%
1800
11th to 20thNight
11%11%48%6%37%6%6%7%31%
1643
21st to endNight
12%9%38%6%45%6%6%7%34%
1512
May1st to 10thNight
11%7%35%5%35%6%6%7%42%
1440
11th to 20thNight
8%5%25%5%45%6%7%9%44%
1418
21st to endNight
17%6%26%5%245%6%7%41%
1358
June1st to 10thNight
12%6%345%445%7%11%39%
1238
11th to 20thNight
19%425%7%47%5%6%6%34%
1080
21st to endNight
7%5%345%26%6%8%9%45%
1195
July1st to 10thNight
5%325%5%35%5%8%11%48%
1260
11th to 20thNight
7%4234345%7%10%50%
1260
21st to endNight
311332446%9%63%
1405
August1st to 10thNight
5%2134246%6%9%58%
1432
11th to 20thNight
7%4145%35%6%5%9%51%
1540
21st to endNight
8%424425%36%9%54%
1804
September1st to 10thNight
9%425%6%35%46%7%50%
1800
11th to 20thNight
11%5%35%5%3445%8%47%
1800
21st to endNight
9%5%2433345%7%54%
2061
October1st to 10thNight
13%9%345%3445%8%42%
2160
11th to 20thNight
7%7%36%5%35%447%50%
2160
21st to endNight
9%11%5%8%6%35%5%6%7%35%
2623
November1st to 10thNight
15%13%5%8%6%3445%6%32%
2590
11th to 20thNight
6%9%5%11%9%5%7%47%7%30%
2660
21st to endNight
6%12%6%11%7%45%5%5%7%31%
2660
December1st to 10thNight
8%10%5%9%10%5%6%5%6%8%26%
2979
11th to 20thNight
7%12%5%11%9%5%6%6%6%7%25%
3753
21st to endNight
36%36%6%445%5%6%52%
5237

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
54%8%14%16%8%
1329
11th to 20thDay
54%9%15%14%6%2
1281
21st to endDay
58%9%12%15%6%
1443
February1st to 10thDay
60%7%10%17%6%
1581
11th to 20thDay
55%6%13%17%9%1
1584
21st to endDay
55%6%14%17%7%
1332
March1st to 10thDay
58%9%14%16%3
1822
11th to 20thDay
50%7%16%19%7%1
1980
21st to endDay
52%9%17%16%5%
2243
April1st to 10thDay
46%7%14%20%11%1
2160
11th to 20thDay
52%6%15%19%7%1
2265
21st to endDay
48%7%14%23%8%1
2448
May1st to 10thDay
47%6%12%25%8%1
2520
11th to 20thDay
38%8%13%28%12%1
2482
21st to endDay
47%8%13%20%12%1
2915
June1st to 10thDay
43%7%13%24%11%1
2718
11th to 20thDay
51%8%13%20%7%1
2880
21st to endDay
38%10%19%24%9%1
2756
July1st to 10thDay
31%10%19%30%9%1
2626
11th to 20thDay
32%9%18%30%10%
2619
21st to endDay
25%8%20%35%12%1
2750
August1st to 10thDay
32%9%21%26%12%1
2491
11th to 20thDay
33%9%20%27%10%
2360
21st to endDay
32%6%15%34%12%1
2552
September1st to 10thDay
34%8%15%25%14%4
2160
11th to 20thDay
39%6%15%28%10%2
2160
21st to endDay
31%6%15%33%14%1
1896
October1st to 10thDay
42%6%18%25%8%1
1800
11th to 20thDay
40%6%15%30%9%
1800
21st to endDay
48%9%15%21%7%
1712
November1st to 10thDay
57%5%12%19%8%
1488
11th to 20thDay
56%7%14%18%5%
1520
21st to endDay
57%7%16%17%3
1520
December1st to 10thDay
56%9%14%15%6%
1196
11th to 20thDay
54%8%19%11%7%
1440
21st to endDay
37%6%15%21%16%5%
2413
January1st to 10thNight
50%9%17%18%6%
2836
11th to 20thNight
53%7%17%17%6%1
2752
21st to endNight
57%9%14%12%7%
2912
February1st to 10thNight
53%7%13%19%7%
2394
11th to 20thNight
53%7%15%16%9%
2273
21st to endNight
46%6%15%23%10%
1924
March1st to 10thNight
50%8%17%18%8%
2133
11th to 20thNight
43%8%15%23%10%1
1980
21st to endNight
48%9%16%18%8%
2112
April1st to 10thNight
39%6%14%24%16%1
1800
11th to 20thNight
50%6%13%18%11%2
1643
21st to endNight
48%7%10%22%10%1
1512
May1st to 10thNight
37%8%11%28%16%
1440
11th to 20thNight
33%8%14%27%15%2
1418
21st to endNight
42%6%13%23%15%1
1358
June1st to 10thNight
37%8%17%27%11%
1238
11th to 20thNight
47%10%11%18%12%1
1080
21st to endNight
31%9%21%29%9%2
1195
July1st to 10thNight
27%10%21%31%10%1
1225
11th to 20thNight
27%8%20%33%11%1
1218
21st to endNight
18%8%18%40%15%2
1327
August1st to 10thNight
22%8%21%34%12%2
1424
11th to 20thNight
29%8%17%31%13%2
1540
21st to endNight
27%7%13%33%19%1
1804
September1st to 10thNight
33%6%14%26%15%6%
1800
11th to 20thNight
35%6%14%29%13%3
1800
21st to endNight
29%6%13%33%17%3
2061
October1st to 10thNight
41%6%15%26%12%1
2160
11th to 20thNight
34%5%16%31%13%1
2160
21st to endNight
49%6%13%23%8%1
2623
November1st to 10thNight
54%6%12%19%8%1
2590
11th to 20thNight
51%9%17%17%6%
2660
21st to endNight
52%7%17%20%4
2660
December1st to 10thNight
55%7%15%16%6%1
2979
11th to 20thNight
56%8%15%15%5%
3751
21st to endNight
32%5%14%26%17%5%
5237

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%26%31%18%6%
180
11th to 20thDay
14%8%22%30%21%5%
166
21st to endDay
12%11%27%34%13%3
202
February1st to 10thDay
13%10%36%30%9%2
240
11th to 20thDay
12%5%34%33%12%4
240
21st to endDay
6%5%28%36%20%6%
198
March1st to 10thDay
11%6%34%32%14%3
276
11th to 20thDay
11%8%30%32%12%6%
420
21st to endDay
14%9%31%27%16%3
462
April1st to 10thDay
10%11%38%28%11%3
420
11th to 20thDay
13%12%33%29%10%3
412
21st to endDay
17%11%28%31%12%1
528
May1st to 10thDay
13%6%25%29%19%7%
603
11th to 20thDay
10%8%23%33%19%7%
625
21st to endDay
14%9%21%27%22%8%
679
June1st to 10thDay
12%9%26%28%20%5%
630
11th to 20thDay
19%13%25%25%13%5%
630
21st to endDay
11%7%21%32%23%7%
630
July1st to 10thDay
7%424%35%23%7%
621
11th to 20thDay
10%6%27%29%21%7%
618
21st to endDay
7%424%28%27%9%
684
August1st to 10thDay
10%5%20%32%23%9%
626
11th to 20thDay
9%8%19%30%28%7%
498
21st to endDay
13%5%19%34%22%8%
495
September1st to 10thDay
14%8%28%28%18%4
450
11th to 20thDay
18%7%25%30%18%3
450
21st to endDay
16%7%30%30%12%6%
361
October1st to 10thDay
19%426%27%18%6%
270
11th to 20thDay
10%7%30%31%16%5%
270
21st to endDay
12%9%41%24%10%4
297
November1st to 10thDay
19%9%29%31%11%1
270
11th to 20thDay
12%11%35%30%9%2
270
21st to endDay
8%8%36%31%12%5%
270
December1st to 10thDay
9%334%35%13%7%
182
11th to 20thDay
10%13%33%32%11%1
180
21st to endDay
12%333%29%20%3
198
January1st to 10thNight
9%7%34%36%13%2
950
11th to 20thNight
10%9%34%34%12%1
918
21st to endNight
13%8%36%33%10%1
990
February1st to 10thNight
10%6%29%35%17%3
774
11th to 20thNight
11%7%29%36%14%2
704
21st to endNight
6%424%35%26%6%
592
March1st to 10thNight
10%5%31%37%14%3
720
11th to 20thNight
9%6%30%38%15%2
720
21st to endNight
12%7%27%36%15%3
726
April1st to 10thNight
11%9%29%38%12%1
540
11th to 20thNight
16%10%30%30%12%1
533
21st to endNight
17%7%28%34%13%
540
May1st to 10thNight
14%425%38%18%2
540
11th to 20thNight
11%7%26%35%21%2
531
21st to endNight
19%8%18%33%19%3
389
June1st to 10thNight
13%6%26%36%16%2
360
11th to 20thNight
20%8%19%34%18%1
360
21st to endNight
9%6%20%39%24%3
360
July1st to 10thNight
6%321%47%21%1
350
11th to 20thNight
8%326%44%17%2
348
21st to endNight
3324%44%24%2
420
August1st to 10thNight
5%320%42%27%3
537
11th to 20thNight
7%319%41%27%3
534
21st to endNight
10%324%38%25%1
594
September1st to 10thNight
11%425%43%15%2
540
11th to 20thNight
14%423%39%19%1
540
21st to endNight
11%432%36%15%2
713
October1st to 10thNight
17%6%26%35%16%
720
11th to 20thNight
11%5%31%36%15%2
720
21st to endNight
16%7%35%31%11%1
949
November1st to 10thNight
21%8%29%33%8%1
925
11th to 20thNight
10%10%33%33%12%2
950
21st to endNight
12%7%37%33%10%1
950
December1st to 10thNight
13%6%33%30%15%3
950
11th to 20thNight
11%8%36%31%12%1
950
21st to endNight
12%5%29%35%16%4
1045
Page generated at 2024-01-11 03:22:38. Version ac07

Copyright 2024 Attilla Danko


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