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 2017-04-28.

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
32%
14227
12%
45646
8%
14195
38%
14195
17%
32991

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%
579
15%
1647
5%
579
37%
579
22%
1159
May1st to 15thNight
32%
375
16%
1365
13%
375
42%
375
17%
922
May16th to endNight
30%
343
12%
1369
10%
342
41%
342
15%
935
June1st to 15thNight
33%
330
6%
1320
6%
330
38%
330
13%
918
June16th to endNight
45%
330
7%
1320
9%
330
47%
330
17%
880
July1st to 15thNight
51%
310
11%
1240
16%
310
56%
310
21%
770
July16th to endNight
49%
348
10%
1306
12%
326
53%
326
19%
833
August1st to 15thNight
56%
345
12%
1326
13%
343
58%
343
19%
857
August16th to endNight
53%
649
16%
1699
10%
649
55%
649
31%
1122
September1st to 15thNight
46%
660
13%
1661
7%
660
47%
660
29%
1147
September16th to endNight
44%
657
19%
1815
13%
657
48%
657
29%
1193
October1st to 15thNight
32%
660
19%
1917
9%
660
42%
660
22%
1341
October16th to endNight
27%
704
10%
2288
7%
704
32%
704
16%
1681
November1st to 15thNight
29%
700
16%
2277
11%
700
37%
700
16%
1634
November16th to endNight
27%
720
12%
2496
8%
720
34%
720
12%
1871
December1st to 15thNight
21%
720
8%
2520
3%
720
27%
720
11%
1950
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
19%8%36%5%3445%6%32%
46060
Night
19%9%36%5%24445%32%
45816
TransparencyDay
51%7%12%18%8%1
45747
Night
53%6%11%18%9%1
45647
SeeingDay
23%6%25%26%13%4
5029
Night
24%5%29%30%9%
14227

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
21%7%25%423445%37%
2260
May1st to 15thDay
21%6%35%5%2445%6%34%
2265
16th to endDay
21%6%26%6%33446%31%
2394
June1st to 15thDay
23%6%345%25%5%6%7%28%
2310
16th to endDay
18%7%35%5%45%6%6%8%28%
2310
July1st to 15thDay
13%5%25%5%46%7%7%8%33%
2310
16th to endDay
14%5%25%7%36%6%7%8%32%
2458
August1st to 15thDay
16%5%26%6%45%6%6%9%29%
2283
16th to endDay
10%4145%345%7%9%42%
2150
September1st to 15thDay
17%5%25%434446%40%
1969
16th to endDay
17%5%24324345%45%
1815
October1st to 15thDay
23%7%35%5%34345%33%
1712
16th to endDay
24%10%36%5%3445%5%27%
1584
November1st to 15thDay
19%9%36%6%35%435%31%
1581
16th to endDay
22%11%45%333335%32%
1461
December1st to 15thDay
28%12%35%6%3423425%
1440
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%
1647
May1st to 15thNight
19%7%36%425%35%5%35%
1365
16th to endNight
21%6%35%434435%35%
1367
June1st to 15thNight
24%6%45%435%45%7%30%
1320
16th to endNight
18%5%345%25%5%6%10%32%
1320
July1st to 15thNight
13%425%5%35%6%6%8%38%
1320
16th to endNight
14%5%345%35%46%7%39%
1402
August1st to 15thNight
13%6%25%5%35%5%5%8%38%
1336
16th to endNight
14%4245%2445%7%45%
1699
September1st to 15thNight
17%4244235%5%7%41%
1661
16th to endNight
19%5%13313435%47%
1815
October1st to 15thNight
18%6%36%5%34345%38%
1917
16th to endNight
28%7%35%422336%32%
2288
November1st to 15thNight
21%7%36%5%24335%34%
2277
16th to endNight
25%11%46%43433428%
2496
December1st to 15thNight
24%11%5%7%5%2333426%
2520
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
2260
May1st to 15thDay
49%411%19%13%1
2265
16th to endDay
51%7%10%18%9%1
2398
June1st to 15thDay
51%8%13%15%9%1
2310
16th to endDay
50%9%12%18%8%
2310
July1st to 15thDay
41%11%15%21%9%
2161
16th to endDay
47%11%16%18%6%
2291
August1st to 15thDay
47%12%16%18%5%
2269
16th to endDay
33%10%21%24%9%
2150
September1st to 15thDay
43%7%15%22%10%
1969
16th to endDay
40%5%14%29%9%
1815
October1st to 15thDay
52%6%10%22%7%
1712
16th to endDay
57%8%12%17%4
1584
November1st to 15thDay
54%7%12%17%8%
1581
16th to endDay
55%6%11%19%6%
1461
December1st to 15thDay
63%413%14%3
1440
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%17%15%4
1647
May1st to 15thNight
50%49%16%15%3
1365
16th to endNight
51%5%9%18%11%2
1369
June1st to 15thNight
52%6%14%15%9%1
1320
16th to endNight
44%10%12%18%13%1
1320
July1st to 15thNight
39%9%15%22%11%1
1240
16th to endNight
41%10%16%21%10%
1306
August1st to 15thNight
41%10%17%23%6%
1326
16th to endNight
37%7%17%27%10%
1699
September1st to 15thNight
41%7%15%24%11%
1661
16th to endNight
40%5%12%29%11%
1815
October1st to 15thNight
48%5%12%22%11%
1917
16th to endNight
55%5%12%18%7%
2288
November1st to 15thNight
52%7%13%17%8%1
2277
16th to endNight
60%411%16%6%
2496
December1st to 15thNight
63%5%13%15%3
2520
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%11%30%21%11%2
259
May1st to 15thDay
26%8%25%25%10%3
228
16th to endDay
22%9%27%23%14%2
267
June1st to 15thDay
28%8%27%20%12%2
255
16th to endDay
19%326%28%18%3
255
July1st to 15thDay
16%225%28%19%6%
245
16th to endDay
17%319%36%18%4
270
August1st to 15thDay
22%317%28%20%6%
253
16th to endDay
11%224%26%21%13%
268
September1st to 15thDay
20%5%18%26%18%10%
255
16th to endDay
20%5%28%22%14%9%
254
October1st to 15thDay
23%5%27%25%14%2
255
16th to endDay
32%6%22%24%13%
240
November1st to 15thDay
25%6%28%24%13%1
235
16th to endDay
35%6%27%18%11%1
81
December1st to 15thDay
41%123%25%35%
60
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%
579
May1st to 15thNight
22%6%31%29%8%
375
16th to endNight
25%434%28%8%
343
June1st to 15thNight
28%326%30%10%
330
16th to endNight
20%224%41%11%
330
July1st to 15thNight
14%226%36%19%1
310
16th to endNight
16%122%44%13%1
348
August1st to 15thNight
15%217%42%20%1
345
16th to endNight
16%222%36%20%1
649
September1st to 15thNight
21%223%37%12%1
660
16th to endNight
20%6%25%29%17%1
657
October1st to 15thNight
21%6%31%29%10%
660
16th to endNight
31%6%30%25%6%
704
November1st to 15thNight
26%5%31%26%9%1
700
16th to endNight
30%8%26%23%10%1
720
December1st to 15thNight
31%6%30%25%5%
720
16th to endNight
32%7%27%24%6%
768
Page generated at 2017-04-29 09:45:05. Version ac04

Copyright 2017 A. Danko


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