Fort Frances
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Frances clear sky chart from 2005-11-06 to 2024-01-12.

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
32%
25033
8%
74710
4%
24977
35%
24977
10%
61572

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
26%
950
6%
2837
4%
946
29%
946
6%
2472
January11th to 20thNight
20%
906
4%
2716
1%
906
23%
906
5%
2447
January21st to endNight
20%
990
6%
2698
2%
990
24%
990
8%
2348
February1st to 10thNight
27%
900
7%
2340
2%
900
30%
900
10%
1969
February11th to 20thNight
32%
878
12%
2274
6%
875
35%
875
14%
1822
February21st to endNight
30%
736
9%
1920
3%
736
34%
736
10%
1626
March1st to 10thNight
30%
632
8%
2075
4%
632
33%
632
8%
1711
March11th to 20thNight
32%
540
12%
1980
7%
540
39%
540
9%
1565
March21st to endNight
31%
594
10%
2142
8%
594
37%
594
9%
1708
April1st to 10thNight
29%
540
10%
1800
8%
540
35%
540
11%
1418
April11th to 20thNight
30%
533
12%
1678
8%
533
36%
533
11%
1335
April21st to endNight
35%
540
9%
1602
6%
540
38%
540
10%
1324
May1st to 10thNight
35%
540
9%
1440
4%
540
37%
540
13%
1168
May11th to 20thNight
37%
531
11%
1416
4%
531
40%
531
15%
1128
May21st to endNight
42%
584
8%
1513
2%
582
45%
582
15%
1193
June1st to 10thNight
42%
540
5%
1260
2%
540
44%
540
15%
1024
June11th to 20thNight
42%
540
8%
1260
2%
540
46%
540
19%
983
June21st to endNight
48%
540
6%
1260
4%
540
50%
540
19%
989
July1st to 10thNight
58%
525
8%
1225
5%
525
59%
525
26%
905
July11th to 20thNight
52%
522
11%
1218
5%
522
55%
522
21%
929
July21st to endNight
58%
591
10%
1445
3%
558
57%
558
20%
1087
August1st to 10thNight
56%
537
13%
1481
6%
534
60%
534
22%
1058
August11th to 20thNight
55%
534
14%
1600
10%
534
60%
534
17%
1171
August21st to endNight
50%
594
13%
1830
11%
594
54%
594
18%
1319
September1st to 10thNight
47%
540
11%
1800
11%
540
51%
540
16%
1313
September11th to 20thNight
43%
540
12%
1820
11%
540
47%
540
14%
1339
September21st to endNight
32%
608
11%
2048
7%
608
38%
608
11%
1589
October1st to 10thNight
30%
720
11%
2160
7%
720
33%
720
11%
1712
October11th to 20thNight
27%
720
7%
2160
3%
720
30%
720
8%
1812
October21st to endNight
21%
827
7%
2509
3%
827
25%
827
8%
2128
November1st to 10thNight
23%
925
8%
2591
3%
925
28%
925
9%
2205
November11th to 20thNight
20%
950
6%
2660
3%
950
22%
950
5%
2387
November21st to endNight
16%
950
6%
2660
2%
950
20%
950
6%
2319
December1st to 10thNight
20%
950
2%
2660
1%
950
22%
950
4%
2441
December11th to 20thNight
17%
949
4%
3452
1%
949
20%
949
3%
3015
December21st to endNight
18%
1037
2%
5180
1%
1026
20%
1026
2%
4613

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
14%10%48%6%45%5%5%7%32%
74740
Night
13%11%5%9%7%45%5%5%6%31%
74973
TransparencyDay
34%38%8%14%6%
74432
Night
36%38%8%13%6%
74815
SeeingDay
18%11%30%26%12%3
15000
Night
18%9%32%29%11%1
25046

By Month

Percentage Cloud Cover NE (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
12%12%7%11%8%6%5%5%6%7%21%
1328
11th to 20thDay
11%15%5%12%8%46%6%5%7%22%
1267
21st to endDay
10%14%7%12%11%6%8%7%7%7%11%
1651
February1st to 10thDay
7%12%6%10%8%39%9%6%7%21%
1620
11th to 20thDay
9%10%5%9%8%5%6%6%5%6%30%
1574
21st to endDay
8%11%5%12%8%45%448%30%
1336
March1st to 10thDay
8%13%5%7%7%46%5%6%7%33%
1898
11th to 20thDay
10%12%410%7%4346%6%33%
1980
21st to endDay
15%9%46%5%345%5%8%34%
2214
April1st to 10thDay
16%9%48%5%45%5%5%6%32%
2160
11th to 20thDay
16%10%47%5%35%5%5%8%32%
2230
21st to endDay
17%11%45%5%445%46%34%
2358
May1st to 10thDay
18%10%36%5%35%5%5%7%33%
2520
11th to 20thDay
16%8%36%6%36%5%5%7%34%
2479
21st to endDay
18%6%36%5%2446%7%38%
2761
June1st to 10thDay
15%6%26%6%35%6%6%9%37%
2700
11th to 20thDay
16%5%46%6%35%6%5%7%38%
2700
21st to endDay
14%6%36%6%45%6%7%9%33%
2700
July1st to 10thDay
9%424446%5%7%9%46%
2700
11th to 20thDay
14%5%36%5%35%5%5%9%40%
2700
21st to endDay
11%5%35%435%5%5%9%45%
2788
August1st to 10thDay
10%6%25%5%45%6%7%9%42%
2446
11th to 20thDay
11%425%5%46%6%7%10%42%
2301
21st to endDay
12%6%35%5%445%5%8%43%
2525
September1st to 10thDay
13%6%36%5%35%46%7%43%
2160
11th to 20thDay
16%6%36%5%35%5%5%8%37%
2138
21st to endDay
21%6%37%4235%5%6%37%
1893
October1st to 10thDay
19%11%37%6%3445%7%30%
1800
11th to 20thDay
20%13%48%6%35%5%5%5%27%
1800
21st to endDay
19%18%49%6%34345%24%
1845
November1st to 10thDay
15%14%8%10%6%45%45%5%24%
1487
11th to 20thDay
14%17%9%14%8%4435%5%19%
1520
21st to endDay
14%15%8%15%10%4443418%
1520
December1st to 10thDay
11%14%7%15%10%5%8%6%45%15%
1520
11th to 20thDay
10%17%9%13%8%5%5%5%4420%
1679
21st to endDay
20%19%8%11%9%4434415%
2442
January1st to 10thNight
8%13%7%12%10%5%6%7%6%5%22%
2837
11th to 20thNight
12%14%7%11%9%6%7%6%5%6%18%
2716
21st to endNight
10%16%7%12%8%46%7%7%7%16%
2698
February1st to 10thNight
8%10%5%11%9%5%8%6%6%7%25%
2340
11th to 20thNight
9%9%410%7%45%6%5%7%34%
2273
21st to endNight
8%12%6%11%8%5%5%5%5%6%29%
1920
March1st to 10thNight
11%10%5%10%6%46%5%5%6%31%
2064
11th to 20thNight
10%10%46%7%35%5%5%6%39%
1979
21st to endNight
15%9%48%7%3445%6%34%
2142
April1st to 10thNight
16%10%48%6%3445%6%33%
1800
11th to 20thNight
17%10%47%5%4445%6%35%
1678
21st to endNight
19%11%47%6%45%446%32%
1602
May1st to 10thNight
17%9%35%5%3445%7%37%
1440
11th to 20thNight
17%7%344245%6%8%38%
1416
21st to endNight
17%7%35%5%2445%7%42%
1512
June1st to 10thNight
16%6%26%5%3345%7%42%
1260
11th to 20thNight
12%6%25%5%345%5%7%46%
1260
21st to endNight
14%5%25%425%5%6%9%43%
1260
July1st to 10thNight
7%3145%345%6%9%54%
1260
11th to 20thNight
8%425%425%5%6%10%49%
1260
21st to endNight
7%325%42345%8%56%
1530
August1st to 10thNight
7%41442446%9%54%
1490
11th to 20thNight
13%5%244345%5%7%48%
1600
21st to endNight
12%5%245%2336%8%50%
1830
September1st to 10thNight
13%6%26%5%2345%7%47%
1800
11th to 20thNight
14%6%35%5%24448%45%
1820
21st to endNight
19%9%35%43345%7%38%
2048
October1st to 10thNight
16%12%46%435%46%7%33%
2160
11th to 20thNight
19%13%5%7%434446%30%
2160
21st to endNight
19%14%5%9%6%35%5%5%6%24%
2509
November1st to 10thNight
15%17%6%9%7%35%345%26%
2591
11th to 20thNight
16%16%7%12%9%45%5%36%17%
2660
21st to endNight
14%15%6%12%10%46%445%19%
2660
December1st to 10thNight
9%14%7%15%11%5%8%5%5%6%14%
2660
11th to 20thNight
11%13%7%13%11%5%6%5%5%6%17%
3513
21st to endNight
20%18%8%12%9%45%44414%
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
38%41%7%13%2
1329
11th to 20thDay
40%43%8%7%2
1267
21st to endDay
45%38%6%6%5%
1651
February1st to 10thDay
37%38%6%11%7%1
1620
11th to 20thDay
33%37%9%13%7%1
1583
21st to endDay
37%36%9%10%6%
1336
March1st to 10thDay
36%38%9%11%5%
1900
11th to 20thDay
36%37%9%11%7%
1980
21st to endDay
36%37%10%11%6%1
2214
April1st to 10thDay
36%37%413%10%1
2160
11th to 20thDay
36%35%8%12%8%
2230
21st to endDay
35%38%5%14%7%1
2358
May1st to 10thDay
35%37%7%12%7%1
2520
11th to 20thDay
30%39%7%15%7%1
2483
21st to endDay
31%38%7%13%10%1
2761
June1st to 10thDay
31%40%8%14%6%
2700
11th to 20thDay
31%39%8%13%9%
2700
21st to endDay
29%39%9%16%5%1
2700
July1st to 10thDay
20%40%9%22%8%1
2626
11th to 20thDay
25%41%9%18%8%
2619
21st to endDay
26%40%8%17%7%1
2633
August1st to 10thDay
26%39%11%17%7%1
2431
11th to 20thDay
24%40%10%20%5%
2301
21st to endDay
24%38%9%21%8%
2525
September1st to 10thDay
26%38%8%21%8%
2160
11th to 20thDay
29%38%13%16%4
2138
21st to endDay
30%38%9%20%4
1893
October1st to 10thDay
33%38%11%15%3
1800
11th to 20thDay
43%37%7%10%3
1800
21st to endDay
42%38%7%11%3
1845
November1st to 10thDay
36%42%8%9%4
1487
11th to 20thDay
44%40%49%3
1520
21st to endDay
42%40%9%7%2
1520
December1st to 10thDay
46%42%5%6%1
1520
11th to 20thDay
47%33%7%11%2
1680
21st to endDay
60%24%5%9%2
2442
January1st to 10thNight
40%41%6%10%3
2837
11th to 20thNight
43%42%5%8%1
2716
21st to endNight
41%38%5%10%4
2698
February1st to 10thNight
37%37%7%11%7%1
2340
11th to 20thNight
30%38%10%14%8%
2274
21st to endNight
38%36%8%11%6%1
1920
March1st to 10thNight
37%38%9%11%5%1
2075
11th to 20thNight
32%38%7%15%7%
1980
21st to endNight
36%36%9%12%6%1
2142
April1st to 10thNight
32%37%6%13%11%1
1800
11th to 20thNight
35%35%7%13%10%1
1678
21st to endNight
37%37%413%8%1
1602
May1st to 10thNight
33%37%7%14%9%
1440
11th to 20thNight
28%38%7%18%7%2
1417
21st to endNight
28%38%8%13%11%2
1513
June1st to 10thNight
29%39%9%15%8%
1260
11th to 20thNight
23%38%10%18%10%1
1260
21st to endNight
24%39%13%16%7%1
1260
July1st to 10thNight
16%38%12%24%10%
1225
11th to 20thNight
19%40%11%20%9%
1218
21st to endNight
20%40%11%20%9%1
1445
August1st to 10thNight
17%38%10%22%11%1
1481
11th to 20thNight
22%38%10%22%9%
1600
21st to endNight
21%38%11%21%10%
1830
September1st to 10thNight
23%38%10%20%9%
1800
11th to 20thNight
25%38%11%20%6%
1820
21st to endNight
30%37%8%21%3
2048
October1st to 10thNight
31%38%8%18%5%
2160
11th to 20thNight
38%37%10%13%1
2160
21st to endNight
37%40%8%12%2
2509
November1st to 10thNight
36%41%7%11%5%1
2591
11th to 20thNight
43%41%5%7%3
2660
21st to endNight
39%41%10%7%3
2660
December1st to 10thNight
46%42%6%6%1
2660
11th to 20thNight
49%34%7%7%3
3511
21st to endNight
60%26%5%7%2
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
14%12%38%24%11%1
270
11th to 20thDay
19%9%30%33%7%1
243
21st to endDay
18%11%33%23%14%1
264
February1st to 10thDay
16%12%46%22%5%
240
11th to 20thDay
16%17%37%18%8%5%
240
21st to endDay
20%17%38%21%31
198
March1st to 10thDay
14%11%38%25%10%2
240
11th to 20thDay
15%14%35%20%13%5%
240
21st to endDay
18%14%30%24%11%2
300
April1st to 10thDay
22%12%32%22%11%
420
11th to 20thDay
21%14%30%25%9%1
508
21st to endDay
22%11%29%25%13%1
600
May1st to 10thDay
23%16%31%19%9%2
603
11th to 20thDay
22%11%28%24%12%3
625
21st to endDay
23%9%26%32%9%3
679
June1st to 10thDay
16%10%29%29%14%3
630
11th to 20thDay
17%13%33%24%11%2
630
21st to endDay
16%8%26%29%15%5%
630
July1st to 10thDay
11%7%28%31%17%7%
621
11th to 20thDay
15%10%28%26%16%5%
618
21st to endDay
11%8%26%29%17%7%
684
August1st to 10thDay
9%9%26%34%17%4
626
11th to 20thDay
13%7%25%30%17%9%
615
21st to endDay
16%9%27%27%18%3
644
September1st to 10thDay
16%11%28%28%15%2
450
11th to 20thDay
18%10%31%28%12%2
428
21st to endDay
28%10%33%19%9%1
270
October1st to 10thDay
23%13%28%25%9%3
270
11th to 20thDay
21%16%34%24%5%
270
21st to endDay
33%16%32%15%41
297
November1st to 10thDay
21%15%35%21%7%1
270
11th to 20thDay
24%17%32%19%7%
270
21st to endDay
26%16%34%20%41
270
December1st to 10thDay
19%13%33%27%8%
270
11th to 20thDay
19%14%42%20%4
270
21st to endDay
20%12%36%22%7%3
297
January1st to 10thNight
14%12%37%25%10%2
950
11th to 20thNight
18%9%37%26%9%1
906
21st to endNight
19%9%36%28%7%
990
February1st to 10thNight
13%9%36%31%10%1
900
11th to 20thNight
14%9%37%28%10%3
879
21st to endNight
14%9%35%28%11%3
736
March1st to 10thNight
16%10%33%29%10%1
635
11th to 20thNight
15%12%35%31%7%1
540
21st to endNight
20%11%30%24%12%4
594
April1st to 10thNight
19%11%32%28%9%1
540
11th to 20thNight
22%8%33%26%10%1
533
21st to endNight
23%9%24%33%10%
540
May1st to 10thNight
22%7%31%31%8%1
540
11th to 20thNight
21%8%31%31%8%2
531
21st to endNight
19%6%27%38%9%1
584
June1st to 10thNight
17%8%27%34%14%1
540
11th to 20thNight
13%7%31%34%15%
540
21st to endNight
15%427%34%19%1
540
July1st to 10thNight
8%326%41%22%1
525
11th to 20thNight
11%428%38%18%1
522
21st to endNight
8%426%36%23%3
591
August1st to 10thNight
8%228%41%19%2
537
11th to 20thNight
14%5%21%35%22%3
534
21st to endNight
14%7%25%35%20%1
594
September1st to 10thNight
17%5%26%35%15%2
540
11th to 20thNight
18%5%32%29%16%1
540
21st to endNight
22%11%30%25%11%1
608
October1st to 10thNight
24%10%31%26%8%
720
11th to 20thNight
25%12%30%26%6%1
720
21st to endNight
27%10%35%23%5%1
827
November1st to 10thNight
23%9%33%27%6%1
925
11th to 20thNight
24%12%32%26%5%1
950
21st to endNight
22%15%37%21%4
950
December1st to 10thNight
17%11%36%27%8%1
950
11th to 20thNight
19%11%36%24%8%1
950
21st to endNight
24%10%31%26%9%2
1045
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