Fort Providence
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Providence clear sky chart from 2005-11-05 to 2017-03-22.

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
37%
14715
6%
45310
5%
14689
39%
14689
14%
34214

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
31%
927
6%
3166
5%
925
32%
925
9%
2513
January16th to endNight
32%
992
10%
3072
7%
992
35%
992
11%
2445
February1st to 15thNight
37%
769
10%
2605
8%
769
41%
769
13%
1845
February16th to endNight
32%
632
9%
2171
9%
632
35%
632
10%
1683
March1st to 15thNight
38%
720
14%
2160
10%
720
41%
720
17%
1541
March16th to endNight
41%
732
12%
1929
7%
732
44%
732
23%
1349
April1st to 15thNight
34%
530
9%
1520
6%
530
38%
530
16%
1099
April16th to endNight
41%
330
3%
1273
2%
330
42%
330
17%
788
May1st to 15thNight
44%
329
0%
1044
0%
329
44%
329
21%
680
May16th to endNight
44%
342
0%
872
0%
342
44%
342
27%
593
June1st to 15thNight
46%
330
0%
660
0%
330
46%
330
27%
491
June16th to endNight
53%
330
0%
660
0%
330
53%
330
31%
480
July1st to 15thNight
50%
310
0%
620
0%
310
50%
310
28%
462
July16th to endNight
56%
348
0%
907
0%
326
60%
326
27%
585
August1st to 15thNight
56%
330
0%
1064
0%
328
56%
328
22%
680
August16th to endNight
49%
362
3%
1412
3%
362
50%
362
15%
954
September1st to 15thNight
42%
599
6%
1589
4%
599
44%
599
20%
1163
September16th to endNight
36%
656
8%
1790
3%
656
39%
656
16%
1363
October1st to 15thNight
40%
660
8%
2071
7%
660
42%
660
16%
1522
October16th to endNight
27%
756
4%
2434
3%
756
29%
756
8%
2033
November1st to 15thNight
31%
879
7%
2649
4%
879
34%
879
10%
2134
November16th to endNight
33%
930
5%
3039
3%
930
35%
930
9%
2450
December1st to 15thNight
29%
930
5%
3147
5%
930
29%
930
7%
2598
December16th to endNight
36%
992
7%
3456
5%
992
38%
992
8%
2763

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%9%47%6%45%5%6%7%31%
45662
Night
9%12%5%9%7%45%5%5%7%26%
45409
TransparencyDay
49%8%18%18%4
45266
Night
55%7%15%16%4
45310
SeeingDay
12%16%19%28%17%5%
6479
Night
13%17%16%28%20%4
14724

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 15thDay
8%16%5%10%12%46%45%8%18%
773
16th to endDay
6%13%8%12%9%47%5%6%7%18%
1152
February1st to 15thDay
48%5%10%8%5%5%6%7%9%27%
1270
16th to endDay
7%13%7%11%6%46%6%6%7%21%
1303
March1st to 15thDay
6%11%6%9%6%445%8%9%27%
1800
16th to endDay
6%11%5%6%5%35%6%5%8%34%
2091
April1st to 15thDay
9%11%36%6%35%446%37%
2095
16th to endDay
47%48%8%5%6%6%5%6%36%
2357
May1st to 15thDay
8%6%47%5%45%6%6%6%40%
2576
16th to endDay
15%6%24424347%44%
2887
June1st to 15thDay
9%6%37%6%46%5%7%8%34%
2970
16th to endDay
9%5%35%5%46%6%6%11%34%
2970
July1st to 15thDay
10%6%36%7%5%6%7%7%8%29%
2970
16th to endDay
9%6%25%7%46%7%7%8%33%
2882
August1st to 15thDay
12%6%26%6%35%5%5%7%37%
2560
16th to endDay
18%8%27%6%35%5%46%29%
2437
September1st to 15thDay
18%7%26%5%345%5%8%31%
2041
16th to endDay
17%12%36%5%36%45%7%26%
1840
October1st to 15thDay
11%13%5%8%6%46%5%47%25%
1559
16th to endDay
15%17%7%8%7%345%5%5%20%
1425
November1st to 15thDay
15%16%7%11%8%3443421%
1205
16th to endDay
10%15%6%9%9%37%5%4421%
921
December1st to 15thDay
13%14%9%10%9%5%5%35%5%16%
810
16th to endDay
7%16%5%12%10%47%47%6%18%
768
January1st to 15thNight
9%15%7%13%7%36%5%5%7%18%
3166
16th to endNight
7%13%7%11%8%47%6%46%21%
3072
February1st to 15thNight
5%7%5%10%9%46%7%6%8%28%
2593
16th to endNight
7%16%6%10%8%45%5%4424%
2171
March1st to 15thNight
411%7%11%7%35%45%6%32%
2160
16th to endNight
5%11%47%6%4445%9%35%
1925
April1st to 15thNight
9%13%47%7%45%5%5%5%31%
1520
16th to endNight
46%5%6%7%46%6%6%8%38%
1273
May1st to 15thNight
6%5%46%7%36%6%6%8%37%
1043
16th to endNight
16%6%35%3225%5%6%41%
872
June1st to 15thNight
7%6%36%7%35%6%7%8%37%
660
16th to endNight
6%336%5%35%9%8%9%38%
660
July1st to 15thNight
8%425%8%46%7%9%11%31%
660
16th to endNight
5%6%25%5%36%6%7%12%37%
977
August1st to 15thNight
9%5%245%25%5%7%8%42%
1070
16th to endNight
14%6%37%5%445%5%7%33%
1412
September1st to 15thNight
15%6%36%5%35%5%6%9%32%
1589
16th to endNight
16%11%37%6%245%5%8%28%
1790
October1st to 15thNight
11%13%37%6%35%445%32%
2071
16th to endNight
15%19%6%10%5%35%445%19%
2434
November1st to 15thNight
16%13%6%11%7%34445%21%
2649
16th to endNight
10%15%7%10%8%35%5%6%6%18%
3039
December1st to 15thNight
8%15%8%11%9%47%5%5%6%16%
3147
16th to endNight
8%14%7%11%10%5%6%6%5%6%17%
3456

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%411%13%5%
773
16th to endDay
63%6%12%11%4
1152
February1st to 15thDay
50%7%16%20%5%
1270
16th to endDay
59%7%12%16%4
1303
March1st to 15thDay
51%6%14%21%41
1800
16th to endDay
45%7%18%23%5%
2091
April1st to 15thDay
47%5%18%21%6%
2095
16th to endDay
45%6%14%26%6%
2357
May1st to 15thDay
41%6%17%23%10%
2576
16th to endDay
40%5%13%27%11%1
2892
June1st to 15thDay
43%7%16%24%7%
2970
16th to endDay
41%9%20%21%6%
2970
July1st to 15thDay
47%10%20%18%2
2781
16th to endDay
41%12%26%19%1
2689
August1st to 15thDay
44%9%23%18%3
2541
16th to endDay
54%9%19%15%
2437
September1st to 15thDay
49%9%23%14%1
2041
16th to endDay
55%8%22%12%1
1840
October1st to 15thDay
57%8%17%15%1
1559
16th to endDay
65%8%16%7%1
1425
November1st to 15thDay
68%5%16%7%2
1205
16th to endDay
63%8%16%8%2
921
December1st to 15thDay
68%6%12%10%1
810
16th to endDay
64%7%13%12%2
768
January1st to 15thNight
64%6%11%14%3
3166
16th to endNight
62%7%11%14%4
3072
February1st to 15thNight
50%7%15%19%6%
2605
16th to endNight
61%6%11%16%3
2171
March1st to 15thNight
50%6%13%22%6%
2160
16th to endNight
45%5%17%25%6%
1929
April1st to 15thNight
51%6%13%22%5%
1520
16th to endNight
41%7%16%22%12%
1273
May1st to 15thNight
42%6%17%19%13%
1044
16th to endNight
40%6%12%25%11%2
872
June1st to 15thNight
39%9%14%25%10%
660
16th to endNight
35%9%22%26%6%
660
July1st to 15thNight
41%10%24%20%3
620
16th to endNight
33%11%30%21%2
907
August1st to 15thNight
35%11%27%22%2
1064
16th to endNight
46%9%19%22%1
1412
September1st to 15thNight
46%10%22%17%3
1589
16th to endNight
52%9%20%14%2
1790
October1st to 15thNight
52%7%20%17%2
2071
16th to endNight
67%7%15%7%
2434
November1st to 15thNight
64%6%13%11%3
2649
16th to endNight
63%8%15%10%1
3039
December1st to 15thNight
66%8%14%10%
3147
16th to endNight
63%8%13%12%2
3456

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
11%6%15%46%16%3
60
16th to endDay
18%410%42%20%3
64
February1st to 15thDay
8%5%30%30%20%6%
60
16th to endDay
10%8%30%31%16%3
86
March1st to 15thDay
10%19%20%22%16%10%
270
16th to endDay
8%21%26%28%12%3
250
April1st to 15thDay
17%27%23%22%9%
209
16th to endDay
9%20%24%31%12%1
257
May1st to 15thDay
7%22%21%25%17%5%
503
16th to endDay
13%20%13%29%17%5%
609
June1st to 15thDay
9%19%21%29%15%4
585
16th to endDay
8%19%15%29%20%6%
585
July1st to 15thDay
10%14%19%30%19%5%
555
16th to endDay
10%18%14%28%22%6%
619
August1st to 15thDay
11%12%13%29%23%9%
502
16th to endDay
24%10%22%25%12%3
268
September1st to 15thDay
25%16%23%17%12%4
255
16th to endDay
19%14%29%21%11%3
255
October1st to 15thDay
21%9%25%25%15%2
164
16th to endDay
36%212%25%17%5%
79
November1st to 15thDay
8%5%23%30%20%13%
60
16th to endDay
16%18%48%11%5%
60
December1st to 15thDay
30%125%23%18%1
60
16th to endDay
10%10%29%29%18%
64
January1st to 15thNight
13%18%17%28%16%5%
930
16th to endNight
12%18%19%30%15%3
992
February1st to 15thNight
6%19%17%30%19%5%
773
16th to endNight
14%18%15%30%17%2
632
March1st to 15thNight
7%21%19%28%19%4
720
16th to endNight
8%19%16%28%23%3
732
April1st to 15thNight
11%23%20%26%16%1
530
16th to endNight
6%23%22%27%18%1
330
May1st to 15thNight
6%22%19%29%19%2
330
16th to endNight
13%21%15%27%20%1
343
June1st to 15thNight
5%19%16%30%25%3
330
16th to endNight
7%19%9%28%31%3
330
July1st to 15thNight
8%14%15%31%27%3
310
16th to endNight
7%18%9%30%29%5%
348
August1st to 15thNight
11%11%13%24%30%8%
330
16th to endNight
16%10%14%26%24%7%
362
September1st to 15thNight
19%13%16%28%16%6%
599
16th to endNight
19%14%19%28%16%2
656
October1st to 15thNight
17%13%17%32%16%2
660
16th to endNight
26%11%17%22%17%4
756
November1st to 15thNight
16%17%14%26%19%4
879
16th to endNight
14%18%12%28%19%6%
930
December1st to 15thNight
14%18%17%29%15%4
930
16th to endNight
11%17%10%26%28%5%
992
Page generated at 2017-03-23 05:36:13. Version ac04

Copyright 2017 A. Danko


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