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 2017-09-22.

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
38%
15154
6%
46532
5%
15128
40%
15128
14%
34963

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
40%
768
11%
2019
6%
768
43%
768
22%
1430
April1st to 15thNight
37%
578
9%
1658
7%
578
41%
578
17%
1173
April16th to endNight
43%
360
3%
1389
2%
360
43%
360
18%
852
May1st to 15thNight
43%
359
0%
1139
0%
359
43%
359
21%
745
May16th to endNight
46%
374
0%
954
0%
374
46%
374
29%
633
June1st to 15thNight
45%
360
0%
720
0%
360
45%
360
27%
538
June16th to endNight
55%
360
0%
720
0%
360
55%
360
31%
523
July1st to 15thNight
51%
340
0%
680
0%
340
51%
340
28%
509
July16th to endNight
57%
376
0%
985
0%
354
60%
354
27%
637
August1st to 15thNight
59%
360
0%
1161
0%
358
59%
358
25%
716
August16th to endNight
48%
395
4%
1541
3%
395
50%
395
16%
1038
September1st to 15thNight
44%
654
6%
1734
4%
654
45%
654
22%
1243
September16th to endNight
39%
683
8%
1862
4%
683
41%
683
17%
1399
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%32%
48438
Night
9%12%5%9%7%45%5%5%7%27%
46631
TransparencyDay
48%8%17%19%5%
48042
Night
54%7%15%17%4
46532
SeeingDay
12%15%19%28%18%5%
7408
Night
13%17%16%28%20%4
15163

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%12%5%6%5%45%6%5%8%33%
2205
April1st to 15thDay
8%11%46%6%35%446%38%
2287
16th to endDay
47%48%7%46%6%5%7%36%
2571
May1st to 15thDay
8%6%46%5%345%6%6%40%
2811
16th to endDay
14%6%24424347%45%
3157
June1st to 15thDay
9%6%37%6%46%5%7%9%34%
3240
16th to endDay
9%5%35%6%46%6%6%10%34%
3240
July1st to 15thDay
10%6%36%7%5%6%7%7%8%31%
3240
16th to endDay
9%6%25%7%36%6%7%8%34%
3112
August1st to 15thDay
12%5%25%5%35%5%5%7%39%
2793
16th to endDay
18%8%26%6%35%5%47%30%
2660
September1st to 15thDay
17%7%26%5%345%5%8%32%
2226
16th to endDay
17%12%35%5%36%46%7%27%
1910
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
6%11%48%6%4445%8%34%
2015
April1st to 15thNight
8%12%37%7%45%5%5%5%33%
1658
16th to endNight
36%46%7%46%6%6%8%38%
1389
May1st to 15thNight
6%5%47%7%35%6%6%8%37%
1138
16th to endNight
14%6%343225%5%6%44%
954
June1st to 15thNight
7%6%36%7%35%5%7%8%37%
720
16th to endNight
6%336%6%35%9%7%9%38%
720
July1st to 15thNight
8%426%8%46%7%8%11%31%
720
16th to endNight
5%5%25%5%36%6%7%11%38%
1055
August1st to 15thNight
9%5%23425%5%7%8%45%
1167
16th to endNight
13%7%27%5%45%5%5%7%34%
1541
September1st to 15thNight
14%7%25%5%35%5%6%9%34%
1734
16th to endNight
16%10%37%6%245%5%8%29%
1862
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
46%7%17%22%4
2205
April1st to 15thDay
46%5%19%22%6%
2287
16th to endDay
44%6%14%26%7%
2571
May1st to 15thDay
41%6%16%24%10%
2811
16th to endDay
38%5%13%28%12%1
3162
June1st to 15thDay
42%8%16%24%7%
3240
16th to endDay
41%9%19%21%7%
3240
July1st to 15thDay
46%10%19%18%3
3051
16th to endDay
40%11%25%20%1
2919
August1st to 15thDay
42%9%22%21%4
2774
16th to endDay
52%9%19%16%1
2660
September1st to 15thDay
48%9%24%15%2
2226
16th to endDay
53%9%22%12%1
1910
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
46%5%16%24%5%
2019
April1st to 15thNight
48%6%14%22%6%
1658
16th to endNight
40%7%15%22%13%
1389
May1st to 15thNight
42%6%17%19%13%
1139
16th to endNight
38%5%12%28%12%2
954
June1st to 15thNight
40%9%13%26%9%
720
16th to endNight
35%9%21%26%6%
720
July1st to 15thNight
41%10%22%21%4
680
16th to endNight
34%11%29%21%3
985
August1st to 15thNight
33%10%25%26%3
1161
16th to endNight
46%9%19%22%2
1541
September1st to 15thNight
44%9%22%19%3
1734
16th to endNight
51%9%20%15%2
1862
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
9%19%24%29%13%3
288
April1st to 15thDay
15%21%22%24%12%3
269
16th to endDay
9%17%22%31%16%3
321
May1st to 15thDay
9%21%21%25%17%4
588
16th to endDay
13%20%16%28%17%4
705
June1st to 15thDay
10%18%22%30%14%3
675
16th to endDay
9%17%15%29%21%6%
675
July1st to 15thDay
10%12%18%31%20%6%
645
16th to endDay
9%16%14%28%24%6%
703
August1st to 15thDay
10%10%12%30%25%11%
585
16th to endDay
23%11%24%25%11%3
332
September1st to 15thDay
23%13%24%19%15%3
315
16th to endDay
17%12%28%22%13%5%
280
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
9%19%17%28%22%3
768
April1st to 15thNight
11%21%20%27%17%1
578
16th to endNight
7%21%21%27%20%1
360
May1st to 15thNight
7%20%21%29%18%2
360
16th to endNight
12%19%16%28%21%1
375
June1st to 15thNight
6%19%16%32%23%2
360
16th to endNight
7%17%9%30%31%3
360
July1st to 15thNight
8%13%14%32%27%4
340
16th to endNight
7%17%9%29%30%5%
376
August1st to 15thNight
11%10%12%25%30%10%
360
16th to endNight
15%10%15%28%23%6%
395
September1st to 15thNight
18%12%16%28%17%5%
654
16th to endNight
18%13%18%28%17%2
683
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 2017-09-23 04:43:44. Version ac04

Copyright 2017 A. Danko


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