Saint-Thomas-de-Caxton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Saint-Thomas-de-Caxton clear sky chart from 2005-11-05 to 2017-12-02.

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
33%
14880
13%
47792
8%
14848
39%
14848
17%
34430

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
22%
720
9%
2506
5%
716
29%
716
10%
1964
January16th to endNight
30%
768
10%
2688
7%
768
36%
768
11%
2058
February1st to 15thNight
26%
704
9%
2343
4%
701
33%
701
12%
1792
February16th to endNight
26%
631
12%
1893
8%
631
32%
631
14%
1435
March1st to 15thNight
26%
720
14%
2159
9%
720
32%
720
15%
1626
March16th to endNight
33%
768
19%
2007
8%
768
40%
768
23%
1418
April1st to 15thNight
28%
718
15%
1796
6%
718
32%
718
20%
1355
April16th to endNight
29%
585
15%
1665
5%
585
37%
585
22%
1168
May1st to 15thNight
32%
409
15%
1489
12%
409
41%
409
16%
1030
May16th to endNight
30%
375
12%
1497
10%
374
41%
374
15%
1026
June1st to 15thNight
35%
360
6%
1440
6%
360
40%
360
14%
989
June16th to endNight
44%
360
7%
1440
9%
360
46%
360
16%
976
July1st to 15thNight
51%
340
10%
1360
15%
340
55%
340
20%
850
July16th to endNight
50%
376
11%
1418
14%
354
54%
354
20%
893
August1st to 15thNight
57%
377
12%
1448
13%
375
59%
375
19%
939
August16th to endNight
53%
708
17%
1854
11%
708
55%
708
32%
1221
September1st to 15thNight
47%
720
13%
1812
7%
720
48%
720
29%
1241
September16th to endNight
47%
717
20%
1980
14%
717
51%
717
30%
1281
October1st to 15thNight
34%
720
18%
2091
9%
720
44%
720
23%
1442
October16th to endNight
27%
768
11%
2496
8%
768
33%
768
16%
1827
November1st to 15thNight
28%
760
15%
2472
10%
760
36%
760
16%
1776
November16th to endNight
26%
780
12%
2704
8%
780
34%
780
12%
2023
December1st to 15thNight
21%
728
7%
2546
3%
728
27%
728
11%
1970
December16th to endNight
20%
768
10%
2688
5%
768
27%
768
9%
2130

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%3445%6%32%
48665
Night
19%9%36%5%24445%33%
47962
TransparencyDay
51%7%12%18%8%1
48352
Night
52%6%11%18%9%1
47793
SeeingDay
23%6%25%26%13%4
5832
Night
24%5%28%30%10%
14880

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
21%14%5%8%6%35%43423%
1432
16th to endDay
13%14%6%7%5%36%45%5%27%
1536
February1st to 15thDay
11%14%5%10%6%46%445%27%
1518
16th to endDay
17%13%49%7%34345%26%
1580
March1st to 15thDay
17%11%5%7%5%34446%29%
1790
16th to endDay
15%9%446%34445%37%
2214
April1st to 15thDay
23%7%35%5%24435%34%
2152
16th to endDay
22%7%25%423445%37%
2294
May1st to 15thDay
22%6%35%5%3445%6%32%
2472
16th to endDay
22%6%26%6%33446%31%
2618
June1st to 15thDay
22%6%345%245%6%7%29%
2520
16th to endDay
19%7%35%5%35%6%6%7%27%
2520
July1st to 15thDay
14%5%25%5%46%6%7%8%33%
2520
16th to endDay
14%5%25%7%35%6%7%8%33%
2654
August1st to 15thDay
15%5%26%6%45%6%6%9%29%
2490
16th to endDay
10%4145%345%7%9%43%
2346
September1st to 15thDay
16%5%25%5%34446%41%
2148
16th to endDay
16%5%24324346%47%
1980
October1st to 15thDay
23%7%25%5%3434434%
1867
16th to endDay
24%9%26%5%34446%28%
1728
November1st to 15thDay
19%8%36%6%35%435%31%
1716
16th to endDay
22%11%45%343335%31%
1583
December1st to 15thDay
28%12%45%6%3423425%
1451
16th to endDay
25%13%5%8%42333425%
1536
January1st to 15thNight
20%15%5%8%6%25%43424%
2506
16th to endNight
15%13%5%9%6%36%44426%
2688
February1st to 15thNight
11%13%410%9%45%445%26%
2341
16th to endNight
17%12%48%6%34445%28%
1893
March1st to 15thNight
19%10%47%6%24445%29%
2147
16th to endNight
15%9%35%5%2434439%
2007
April1st to 15thNight
24%10%35%414345%31%
1796
16th to endNight
22%7%24414347%37%
1665
May1st to 15thNight
22%8%36%325%345%33%
1489
16th to endNight
22%6%35%434446%34%
1495
June1st to 15thNight
23%6%35%435%45%7%31%
1440
16th to endNight
19%5%245%25%5%6%9%32%
1440
July1st to 15thNight
13%425%5%45%5%6%8%38%
1440
16th to endNight
13%5%245%35%46%7%40%
1514
August1st to 15thNight
13%5%26%5%35%5%5%8%38%
1458
16th to endNight
13%4245%2445%7%45%
1854
September1st to 15thNight
17%4244235%5%7%42%
1812
16th to endNight
18%413323435%48%
1980
October1st to 15thNight
18%5%36%5%3434440%
2091
16th to endNight
28%7%25%422336%32%
2496
November1st to 15thNight
22%7%36%6%24335%34%
2472
16th to endNight
24%11%46%43433428%
2704
December1st to 15thNight
25%11%5%7%5%2333426%
2546
16th to endNight
23%15%5%9%5%2333323%
2688

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
64%6%8%13%6%
1433
16th to endDay
58%6%11%16%7%
1536
February1st to 15thDay
59%5%12%15%5%
1520
16th to endDay
60%49%15%8%1
1580
March1st to 15thDay
53%7%12%13%11%1
1800
16th to endDay
47%6%10%18%13%3
2214
April1st to 15thDay
52%49%18%11%3
2152
16th to endDay
48%5%9%18%13%3
2294
May1st to 15thDay
51%5%10%18%12%1
2472
16th to endDay
52%7%11%17%9%1
2622
June1st to 15thDay
51%8%13%16%9%1
2520
16th to endDay
51%9%12%17%8%
2520
July1st to 15thDay
42%11%15%21%9%
2371
16th to endDay
46%10%16%19%6%
2487
August1st to 15thDay
46%12%17%19%4
2476
16th to endDay
34%10%20%25%9%
2346
September1st to 15thDay
43%7%15%22%11%
2148
16th to endDay
38%5%15%30%10%
1980
October1st to 15thDay
52%6%10%23%7%
1867
16th to endDay
56%7%13%17%4
1728
November1st to 15thDay
54%7%12%16%8%
1716
16th to endDay
56%6%11%18%7%
1583
December1st to 15thDay
63%413%14%3
1451
16th to endDay
64%411%11%7%
1536
January1st to 15thNight
64%5%10%15%4
2506
16th to endNight
60%6%9%15%6%
2688
February1st to 15thNight
60%5%11%14%6%
2343
16th to endNight
58%5%10%13%11%
1893
March1st to 15thNight
56%5%9%16%10%1
2160
16th to endNight
47%5%9%17%15%3
2007
April1st to 15thNight
55%37%18%12%2
1796
16th to endNight
47%6%9%18%15%4
1665
May1st to 15thNight
52%49%15%14%3
1489
16th to endNight
51%6%10%18%11%2
1497
June1st to 15thNight
51%6%14%15%9%1
1440
16th to endNight
45%10%12%17%12%1
1440
July1st to 15thNight
39%9%15%21%12%1
1360
16th to endNight
40%9%16%21%10%
1418
August1st to 15thNight
41%10%17%23%6%
1448
16th to endNight
37%7%16%27%10%
1854
September1st to 15thNight
40%7%14%24%11%
1812
16th to endNight
38%5%14%29%12%
1980
October1st to 15thNight
46%5%11%24%11%
2091
16th to endNight
54%5%13%18%7%
2496
November1st to 15thNight
52%6%13%17%8%1
2472
16th to endNight
60%411%16%6%
2704
December1st to 15thNight
63%5%13%15%3
2546
16th to endNight
66%5%9%12%6%
2688

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
25%15%16%35%8%
60
16th to endDay
26%428%31%44
64
February1st to 15thDay
28%7%28%26%8%
94
16th to endDay
26%429%33%5%
239
March1st to 15thDay
25%9%28%28%7%
270
16th to endDay
19%7%29%25%13%3
288
April1st to 15thDay
28%8%24%27%8%2
270
16th to endDay
22%12%31%20%11%2
270
May1st to 15thDay
29%9%25%22%10%2
288
16th to endDay
24%9%28%22%12%2
331
June1st to 15thDay
25%7%27%24%12%2
315
16th to endDay
20%428%27%16%2
315
July1st to 15thDay
18%225%28%18%5%
305
16th to endDay
17%319%36%19%3
326
August1st to 15thDay
19%317%31%21%6%
313
16th to endDay
11%422%26%20%14%
332
September1st to 15thDay
18%5%20%27%18%9%
315
16th to endDay
17%425%23%19%9%
314
October1st to 15thDay
24%6%25%26%13%3
315
16th to endDay
31%6%25%22%13%
288
November1st to 15thDay
27%7%27%24%12%1
280
16th to endDay
34%10%24%21%7%
113
December1st to 15thDay
39%122%25%6%4
63
16th to endDay
42%10%32%14%
64
January1st to 15thNight
29%6%31%26%5%
720
16th to endNight
22%6%28%33%8%1
768
February1st to 15thNight
17%6%35%30%8%
704
16th to endNight
24%5%32%29%6%
631
March1st to 15thNight
26%5%33%30%3
720
16th to endNight
20%6%33%30%8%1
768
April1st to 15thNight
29%7%27%28%6%
718
16th to endNight
26%7%32%25%7%
585
May1st to 15thNight
25%5%30%29%8%
409
16th to endNight
25%433%28%8%
375
June1st to 15thNight
26%325%32%11%
360
16th to endNight
21%225%40%10%
360
July1st to 15thNight
14%226%37%18%1
340
16th to endNight
16%122%44%14%1
376
August1st to 15thNight
15%216%43%20%1
377
16th to endNight
16%222%36%21%1
708
September1st to 15thNight
21%222%37%13%1
720
16th to endNight
19%5%23%30%19%1
717
October1st to 15thNight
20%5%31%30%11%
720
16th to endNight
31%6%29%25%6%
768
November1st to 15thNight
26%5%30%26%10%1
760
16th to endNight
30%7%27%22%10%1
780
December1st to 15thNight
31%6%30%25%5%
728
16th to endNight
32%7%27%24%6%
768
Page generated at 2017-12-03 11:16:39. Version ac04

Copyright 2017 A. Danko


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