Smiths Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Smiths Falls clear sky chart from 2005-11-05 to 2018-01-12.

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
28%
15151
14%
48378
8%
15123
35%
15123
16%
34318

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
15%
765
7%
2662
2%
761
21%
761
7%
2123
January16th to endNight
18%
768
11%
2622
5%
768
25%
768
10%
1982
February1st to 15thNight
15%
701
9%
2287
3%
701
23%
701
10%
1768
February16th to endNight
17%
631
13%
1949
5%
631
27%
631
12%
1472
March1st to 15thNight
18%
720
14%
2091
6%
720
27%
720
15%
1543
March16th to endNight
30%
768
20%
2040
9%
768
38%
768
21%
1424
April1st to 15thNight
22%
718
16%
1796
5%
718
27%
718
19%
1322
April16th to endNight
27%
661
18%
1741
7%
661
33%
661
22%
1219
May1st to 15thNight
34%
360
17%
1440
13%
360
45%
360
17%
944
May16th to endNight
32%
374
13%
1497
9%
374
43%
374
19%
925
June1st to 15thNight
35%
360
10%
1440
9%
360
43%
360
14%
976
June16th to endNight
38%
360
10%
1440
12%
360
44%
360
18%
918
July1st to 15thNight
48%
340
15%
1360
21%
340
54%
340
27%
755
July16th to endNight
55%
376
14%
1418
16%
354
59%
354
27%
809
August1st to 15thNight
49%
461
14%
1532
11%
459
54%
459
24%
961
August16th to endNight
51%
711
22%
1857
11%
711
56%
711
37%
1124
September1st to 15thNight
45%
720
17%
1800
7%
720
49%
720
31%
1217
September16th to endNight
47%
717
25%
1959
16%
717
53%
717
32%
1229
October1st to 15thNight
32%
720
17%
2160
11%
720
40%
720
21%
1470
October16th to endNight
22%
768
12%
2388
6%
768
31%
768
13%
1788
November1st to 15thNight
26%
760
17%
2527
11%
760
34%
760
16%
1758
November16th to endNight
20%
780
11%
2730
7%
780
27%
780
10%
2086
December1st to 15thNight
15%
780
7%
2730
3%
780
20%
780
7%
2170
December16th to endNight
13%
832
9%
2912
4%
832
20%
832
7%
2335

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
18%8%36%5%34446%32%
48970
Night
18%9%36%5%34446%33%
48547
Cloud CoverDay
18%9%36%5%34446%33%
48979
Night
18%9%36%5%24346%33%
48553
TransparencyDay
51%5%11%19%10%1
48657
Night
52%411%19%9%1
48378
SeeingDay
23%13%28%20%9%3
5811
Night
23%13%28%24%9%
15155

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 15thDay
20%16%6%9%7%3434321%
1520
16th to endDay
14%14%5%9%9%44435%22%
1599
February1st to 15thDay
14%13%5%11%8%36%435%22%
1575
16th to endDay
18%14%5%6%7%35%336%24%
1523
March1st to 15thDay
19%10%49%7%45%33426%
1859
16th to endDay
17%8%35%423345%40%
2184
April1st to 15thDay
22%10%36%423345%32%
2152
16th to endDay
20%7%35%424346%36%
2229
May1st to 15thDay
19%8%36%5%3345%6%33%
2511
16th to endDay
17%5%25%5%25%5%5%7%36%
2618
June1st to 15thDay
22%6%25%5%25%45%7%31%
2520
16th to endDay
18%6%25%6%35%5%5%7%32%
2520
July1st to 15thDay
12%5%35%435%5%5%10%38%
2520
16th to endDay
12%5%25%5%47%5%6%8%35%
2654
August1st to 15thDay
12%6%37%6%35%5%5%7%36%
2415
16th to endDay
11%425%5%35%5%5%8%41%
2333
September1st to 15thDay
17%5%2443445%7%41%
2160
16th to endDay
15%5%24423446%46%
1998
October1st to 15thDay
21%7%25%5%33445%34%
1800
16th to endDay
25%11%37%5%33445%25%
1836
November1st to 15thDay
15%8%36%6%46%446%32%
1660
16th to endDay
21%12%48%5%33445%25%
1560
December1st to 15thDay
23%13%5%8%6%34445%19%
1560
16th to endDay
24%15%5%6%5%3443421%
1664
January1st to 15thNight
19%14%5%10%7%3433421%
2662
16th to endNight
14%13%6%9%7%35%345%25%
2622
February1st to 15thNight
14%15%6%11%6%35%445%23%
2285
16th to endNight
17%13%47%7%3434428%
1949
March1st to 15thNight
19%12%48%5%24335%31%
2078
16th to endNight
17%8%46%42434440%
2040
April1st to 15thNight
23%8%36%5%23335%34%
1796
16th to endNight
19%8%25%5%23446%38%
1741
May1st to 15thNight
21%7%3443444437%
1440
16th to endNight
16%6%26%42345%7%39%
1495
June1st to 15thNight
20%6%35%5%3445%7%33%
1440
16th to endNight
15%7%145%25%5%6%8%36%
1440
July1st to 15thNight
10%425%5%244410%45%
1440
16th to endNight
9%333425%5%7%8%45%
1514
August1st to 15thNight
9%5%35%6%35%5%6%8%40%
1542
16th to endNight
10%3143335%5%7%50%
1857
September1st to 15thNight
15%425%5%33445%45%
1800
16th to endNight
16%423323347%48%
1959
October1st to 15thNight
19%6%35%42335%6%36%
2160
16th to endNight
25%10%36%5%23445%28%
2388
November1st to 15thNight
20%10%35%433445%34%
2527
16th to endNight
22%11%5%6%6%25%336%25%
2730
December1st to 15thNight
20%15%5%9%6%3435%421%
2730
16th to endNight
24%15%5%8%7%3433420%
2912

Percentage Cloud Cover SE (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
20%16%6%8%7%4444321%
1520
16th to endDay
15%14%5%9%9%35%436%22%
1599
February1st to 15thDay
15%14%5%11%8%26%44422%
1575
16th to endDay
19%14%5%6%7%35%43424%
1523
March1st to 15thDay
19%10%47%8%4423429%
1869
16th to endDay
17%8%45%32333443%
2183
April1st to 15thDay
22%10%45%423345%33%
2152
16th to endDay
19%9%35%423346%36%
2229
May1st to 15thDay
19%8%36%43345%6%33%
2511
16th to endDay
17%6%25%5%345%5%7%36%
2618
June1st to 15thDay
22%6%26%425%45%7%30%
2520
16th to endDay
19%6%25%6%35%5%5%7%33%
2520
July1st to 15thDay
12%5%245%35%5%6%8%39%
2520
16th to endDay
12%5%25%5%36%6%7%9%34%
2654
August1st to 15thDay
11%6%36%6%445%5%6%39%
2415
16th to endDay
10%5%24435%45%8%45%
2333
September1st to 15thDay
17%5%25%424448%41%
2160
16th to endDay
15%5%24423346%46%
1998
October1st to 15thDay
22%7%245%24446%35%
1800
16th to endDay
24%11%46%5%34435%26%
1836
November1st to 15thDay
15%8%35%8%35%446%32%
1660
16th to endDay
21%11%5%8%6%24345%25%
1560
December1st to 15thDay
23%14%5%8%7%35%435%20%
1560
16th to endDay
25%14%5%7%5%3443321%
1664
January1st to 15thNight
20%14%5%10%8%34335%20%
2662
16th to endNight
14%13%6%10%6%35%346%24%
2622
February1st to 15thNight
14%15%6%10%7%3444423%
2278
16th to endNight
17%13%5%7%7%34345%27%
1949
March1st to 15thNight
19%12%36%5%2324435%
2091
16th to endNight
17%8%36%42333442%
2040
April1st to 15thNight
23%8%36%423335%34%
1796
16th to endNight
19%8%25%423345%39%
1741
May1st to 15thNight
20%8%34424446%37%
1440
16th to endNight
16%5%36%4245%48%39%
1495
June1st to 15thNight
20%6%345%35%35%7%33%
1440
16th to endNight
15%6%24436%6%6%8%36%
1440
July1st to 15thNight
10%4245%2445%9%45%
1440
16th to endNight
8%424435%5%7%9%45%
1514
August1st to 15thNight
9%5%25%6%35%45%8%42%
1542
16th to endNight
10%31342445%7%51%
1857
September1st to 15thNight
15%5%2442345%5%45%
1800
16th to endNight
15%41431335%6%48%
1959
October1st to 15thNight
19%6%36%5%2435%6%36%
2160
16th to endNight
25%10%26%5%23345%28%
2388
November1st to 15thNight
19%10%35%434345%34%
2527
16th to endNight
22%11%5%6%6%34345%25%
2730
December1st to 15thNight
20%16%5%8%6%3434421%
2730
16th to endNight
23%14%5%9%7%3333420%
2912

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
67%39%12%5%1
1521
16th to endDay
63%5%10%12%7%
1599
February1st to 15thDay
64%410%16%3
1577
16th to endDay
62%410%11%10%
1523
March1st to 15thDay
62%310%14%7%1
1869
16th to endDay
47%39%19%15%5%
2184
April1st to 15thDay
53%46%17%14%2
2152
16th to endDay
49%37%20%15%3
2229
May1st to 15thDay
50%49%20%13%2
2511
16th to endDay
46%6%12%20%11%2
2622
June1st to 15thDay
52%5%10%20%10%
2520
16th to endDay
49%6%11%20%10%
2520
July1st to 15thDay
37%6%14%28%12%
2371
16th to endDay
43%8%14%23%9%
2487
August1st to 15thDay
46%6%14%21%10%
2401
16th to endDay
37%5%15%28%12%
2333
September1st to 15thDay
41%5%12%26%12%
2160
16th to endDay
38%5%11%33%11%
1998
October1st to 15thDay
50%5%11%22%9%
1800
16th to endDay
60%5%13%14%6%
1836
November1st to 15thDay
51%5%13%18%9%
1660
16th to endDay
61%5%10%14%7%
1560
December1st to 15thDay
67%5%11%12%3
1560
16th to endDay
66%6%10%11%4
1664
January1st to 15thNight
67%410%12%4
2662
16th to endNight
61%310%16%6%
2622
February1st to 15thNight
63%412%15%4
2287
16th to endNight
59%410%17%8%
1949
March1st to 15thNight
57%311%19%8%
2091
16th to endNight
47%39%19%16%3
2040
April1st to 15thNight
53%38%19%14%1
1796
16th to endNight
46%5%7%19%17%3
1741
May1st to 15thNight
48%5%8%19%14%4
1440
16th to endNight
43%5%14%19%14%1
1497
June1st to 15thNight
50%6%12%19%10%1
1440
16th to endNight
44%7%12%21%14%
1440
July1st to 15thNight
33%5%12%30%16%
1360
16th to endNight
33%7%16%26%14%
1418
August1st to 15thNight
38%7%17%22%13%
1532
16th to endNight
31%5%16%33%13%
1857
September1st to 15thNight
40%5%11%30%11%1
1800
16th to endNight
35%5%11%33%12%
1959
October1st to 15thNight
47%411%23%12%
2160
16th to endNight
57%5%13%17%5%
2388
November1st to 15thNight
51%5%14%17%9%1
2527
16th to endNight
61%5%11%16%4
2730
December1st to 15thNight
65%5%12%12%4
2730
16th to endNight
68%49%12%5%
2912

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
28%21%29%14%6%
82
16th to endDay
44%12%32%8%4
75
February1st to 15thDay
35%23%31%10%
90
16th to endDay
30%20%29%15%4
182
March1st to 15thDay
27%17%28%22%5%
270
16th to endDay
25%17%30%14%9%1
288
April1st to 15thDay
27%23%27%13%8%
270
16th to endDay
23%20%25%18%6%5%
270
May1st to 15thDay
30%12%27%18%7%3
288
16th to endDay
23%15%32%16%10%1
331
June1st to 15thDay
25%13%29%21%8%1
315
16th to endDay
21%10%30%23%11%1
315
July1st to 15thDay
15%7%30%27%15%4
305
16th to endDay
13%7%30%30%14%4
326
August1st to 15thDay
14%8%28%30%12%6%
313
16th to endDay
11%7%28%26%13%12%
332
September1st to 15thDay
17%9%23%22%15%11%
315
16th to endDay
17%8%26%20%17%9%
314
October1st to 15thDay
26%12%26%20%10%3
315
16th to endDay
30%16%28%18%5%
315
November1st to 15thDay
22%15%28%22%8%2
224
16th to endDay
30%23%25%17%3
90
December1st to 15thDay
36%17%30%10%5%
90
16th to endDay
38%28%28%5%
96
January1st to 15thNight
29%18%29%18%4
765
16th to endNight
23%15%33%21%5%
768
February1st to 15thNight
22%21%33%19%3
704
16th to endNight
24%16%35%17%5%
631
March1st to 15thNight
28%15%32%21%2
720
16th to endNight
21%16%27%25%7%1
768
April1st to 15thNight
27%17%27%22%4
718
16th to endNight
24%14%30%21%8%
661
May1st to 15thNight
25%8%26%29%8%1
360
16th to endNight
15%9%38%25%11%
375
June1st to 15thNight
21%11%25%31%9%
360
16th to endNight
16%6%32%30%13%
360
July1st to 15thNight
10%5%27%41%14%
340
16th to endNight
8%327%42%16%1
376
August1st to 15thNight
13%425%34%21%1
461
16th to endNight
11%427%33%20%1
711
September1st to 15thNight
19%6%25%29%18%2
720
16th to endNight
17%8%23%24%23%2
717
October1st to 15thNight
22%10%28%23%13%1
720
16th to endNight
30%12%27%22%6%
768
November1st to 15thNight
26%13%28%20%10%
760
16th to endNight
30%17%25%17%9%
780
December1st to 15thNight
31%19%27%17%3
780
16th to endNight
32%15%30%18%2
832
Page generated at 2018-01-12 22:01:38. Version ac04

Copyright 2018 A. Danko


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