Marten River Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Marten River Provincial Park clear sky chart from 2005-11-05 to 2017-09-21.

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
26%
15051
12%
46768
7%
15019
32%
15019
15%
34235

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
13%
899
7%
2685
3%
895
17%
895
7%
2249
January16th to endNight
21%
821
11%
2594
6%
821
26%
821
9%
2071
February1st to 15thNight
17%
702
9%
2287
4%
701
23%
701
9%
1791
February16th to endNight
16%
631
10%
2042
4%
631
23%
631
9%
1611
March1st to 15thNight
18%
720
13%
1998
5%
720
25%
720
14%
1532
March16th to endNight
29%
768
19%
2112
9%
768
36%
768
22%
1450
April1st to 15thNight
22%
688
14%
1784
5%
688
27%
688
18%
1327
April16th to endNight
27%
540
16%
1620
8%
540
34%
540
19%
1134
May1st to 15thNight
32%
429
16%
1509
11%
429
42%
429
19%
990
May16th to endNight
30%
374
13%
1494
9%
374
41%
374
18%
928
June1st to 15thNight
37%
360
9%
1260
7%
360
43%
360
18%
849
June16th to endNight
37%
360
9%
1260
6%
360
42%
360
21%
821
July1st to 15thNight
44%
340
12%
1190
13%
340
48%
340
28%
681
July16th to endNight
48%
403
14%
1368
14%
379
52%
379
27%
793
August1st to 15thNight
43%
539
12%
1609
9%
536
47%
536
24%
1068
August16th to endNight
44%
588
19%
1734
12%
588
49%
588
28%
1107
September1st to 15thNight
42%
720
16%
1809
7%
720
46%
720
31%
1208
September16th to endNight
41%
681
18%
1900
12%
681
45%
681
29%
1239
October1st to 15thNight
31%
660
15%
1980
10%
660
38%
660
18%
1418
October16th to endNight
21%
704
11%
2143
6%
704
27%
704
11%
1714
November1st to 15thNight
24%
700
12%
2446
9%
700
29%
700
14%
1767
November16th to endNight
19%
720
10%
2520
6%
720
25%
720
9%
1966
December1st to 15thNight
15%
744
7%
2544
2%
744
20%
744
8%
2060
December16th to endNight
13%
960
8%
2880
3%
960
18%
960
7%
2461

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%10%47%6%34446%28%
48100
Night
18%11%47%6%34445%29%
46929
TransparencyDay
56%311%19%8%
47778
Night
57%311%19%8%
46769
SeeingDay
24%11%29%21%9%3
5856
Night
25%10%29%24%9%1
15055

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
22%18%5%10%6%2433418%
1253
16th to endDay
14%17%7%9%8%34446%17%
1626
February1st to 15thDay
10%16%6%10%11%5%6%43420%
1575
16th to endDay
14%18%7%10%6%4333422%
1428
March1st to 15thDay
17%13%5%6%6%3444428%
1950
16th to endDay
14%9%38%6%23345%37%
2112
April1st to 15thDay
23%10%36%5%23346%30%
2175
16th to endDay
21%8%35%423335%37%
2340
May1st to 15thDay
22%8%36%5%3335%6%30%
2442
16th to endDay
20%6%36%5%35%247%34%
2618
June1st to 15thDay
19%8%46%5%35%5%5%7%28%
2700
16th to endDay
18%6%36%6%36%5%6%7%29%
2700
July1st to 15thDay
14%6%36%5%35%46%8%35%
2700
16th to endDay
14%6%25%6%45%5%5%8%34%
2700
August1st to 15thDay
16%7%25%6%45%5%6%8%30%
2340
16th to endDay
17%7%35%5%35%5%48%33%
2456
September1st to 15thDay
20%7%26%5%25%45%6%33%
2148
16th to endDay
22%6%25%5%2445%7%32%
1852
October1st to 15thDay
21%11%36%5%25%445%29%
1650
16th to endDay
32%16%35%42333419%
1727
November1st to 15thDay
21%13%47%6%24336%25%
1411
16th to endDay
27%17%5%9%6%2333416%
1440
December1st to 15thDay
21%18%6%10%7%2344415%
1413
16th to endDay
20%19%9%11%6%4233315%
1344
January1st to 15thNight
20%18%8%9%7%3343316%
2685
16th to endNight
15%15%6%10%8%35%445%19%
2594
February1st to 15thNight
12%13%6%11%9%46%445%20%
2285
16th to endNight
15%18%6%9%8%3433422%
2042
March1st to 15thNight
17%13%6%7%6%34436%26%
1986
16th to endNight
14%9%35%5%2445%6%38%
2112
April1st to 15thNight
22%11%5%5%42344431%
1784
16th to endNight
20%7%26%5%245%46%33%
1620
May1st to 15thNight
19%6%35%5%2445%6%35%
1509
16th to endNight
16%8%25%42446%6%37%
1493
June1st to 15thNight
16%8%36%5%34446%35%
1260
16th to endNight
13%6%36%6%35%5%48%36%
1260
July1st to 15thNight
11%4345%235%6%9%43%
1260
16th to endNight
11%43442445%9%44%
1463
August1st to 15thNight
14%6%16%5%345%5%6%39%
1620
16th to endNight
13%6%26%42435%5%43%
1734
September1st to 15thNight
17%5%24323346%44%
1809
16th to endNight
17%8%24423346%42%
1900
October1st to 15thNight
22%10%345%34435%32%
1980
16th to endNight
28%13%46%5%2432422%
2143
November1st to 15thNight
19%10%37%6%34446%28%
2446
16th to endNight
26%15%5%7%5%23345%21%
2520
December1st to 15thNight
21%18%6%8%5%3434417%
2544
16th to endNight
22%18%7%9%7%3434413%
2880

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
70%28%13%4
1254
16th to endDay
67%36%16%6%
1626
February1st to 15thDay
69%38%13%5%
1577
16th to endDay
66%15%15%10%
1428
March1st to 15thDay
58%310%17%8%
1961
16th to endDay
51%18%20%15%2
2112
April1st to 15thDay
55%28%20%11%1
2175
16th to endDay
50%27%23%14%2
2340
May1st to 15thDay
54%29%19%12%1
2442
16th to endDay
51%311%19%12%
2622
June1st to 15thDay
53%410%21%9%
2700
16th to endDay
52%412%21%8%1
2700
July1st to 15thDay
43%412%28%10%
2541
16th to endDay
48%312%26%7%
2532
August1st to 15thDay
49%317%20%8%
2327
16th to endDay
49%415%25%5%
2456
September1st to 15thDay
50%313%23%7%
2148
16th to endDay
51%315%24%5%
1852
October1st to 15thDay
57%312%19%6%
1650
16th to endDay
69%310%12%4
1727
November1st to 15thDay
61%213%14%6%
1411
16th to endDay
74%18%11%4
1440
December1st to 15thDay
72%38%13%2
1413
16th to endDay
75%16%11%3
1344
January1st to 15thNight
73%27%11%3
2685
16th to endNight
67%26%15%6%
2594
February1st to 15thNight
66%39%14%5%
2287
16th to endNight
67%26%15%7%
2042
March1st to 15thNight
61%210%16%8%1
1998
16th to endNight
47%39%21%15%2
2112
April1st to 15thNight
56%27%18%13%1
1784
16th to endNight
50%39%18%15%2
1620
May1st to 15thNight
48%28%23%14%2
1509
16th to endNight
46%313%21%13%1
1495
June1st to 15thNight
50%310%23%10%2
1260
16th to endNight
45%5%12%23%11%1
1260
July1st to 15thNight
35%415%31%11%1
1190
16th to endNight
37%418%29%10%
1368
August1st to 15thNight
43%5%15%24%9%
1609
16th to endNight
41%315%29%9%
1734
September1st to 15thNight
40%417%26%9%1
1809
16th to endNight
42%215%32%7%
1900
October1st to 15thNight
54%311%20%10%
1980
16th to endNight
67%210%14%5%
2143
November1st to 15thNight
57%314%18%5%
2446
16th to endNight
66%211%13%4
2520
December1st to 15thNight
70%29%13%3
2544
16th to endNight
75%26%10%5%
2880

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
35%8%40%13%3
60
16th to endDay
29%6%28%25%9%1
88
February1st to 15thDay
34%13%37%14%
90
16th to endDay
40%17%33%7%1
81
March1st to 15thDay
27%15%29%23%4
251
16th to endDay
21%17%31%18%7%2
288
April1st to 15thDay
27%16%27%19%8%
270
16th to endDay
27%15%31%11%8%4
270
May1st to 15thDay
32%7%21%21%14%2
288
16th to endDay
24%11%32%22%6%2
331
June1st to 15thDay
22%15%28%25%6%1
495
16th to endDay
18%11%33%24%10%2
495
July1st to 15thDay
16%9%31%28%13%1
475
16th to endDay
15%7%33%25%11%6%
400
August1st to 15thDay
20%423%27%16%8%
313
16th to endDay
23%6%25%19%17%7%
332
September1st to 15thDay
23%6%24%24%14%5%
315
16th to endDay
26%8%26%25%8%5%
275
October1st to 15thDay
25%11%34%17%9%1
255
16th to endDay
35%13%28%17%31
239
November1st to 15thDay
24%14%36%16%43
61
16th to endDay
46%8%25%20%
60
December1st to 15thDay
33%10%43%13%
60
16th to endDay
39%23%32%4
64
January1st to 15thNight
31%13%31%18%5%
900
16th to endNight
24%12%28%23%9%1
821
February1st to 15thNight
20%12%36%23%5%1
704
16th to endNight
25%13%33%21%5%
631
March1st to 15thNight
25%17%32%19%4
720
16th to endNight
18%13%31%24%9%1
768
April1st to 15thNight
28%14%29%21%6%
688
16th to endNight
26%13%29%21%8%1
540
May1st to 15thNight
23%8%27%29%9%1
429
16th to endNight
21%9%32%25%9%
375
June1st to 15thNight
23%7%24%34%10%
360
16th to endNight
18%6%28%31%12%1
360
July1st to 15thNight
12%432%38%12%
340
16th to endNight
13%327%38%15%1
403
August1st to 15thNight
17%324%32%20%1
539
16th to endNight
17%5%26%30%17%2
588
September1st to 15thNight
20%5%27%25%20%1
720
16th to endNight
21%5%26%29%14%2
681
October1st to 15thNight
27%8%27%25%8%
660
16th to endNight
39%7%23%22%5%
704
November1st to 15thNight
26%13%30%21%7%
700
16th to endNight
35%11%25%20%5%
720
December1st to 15thNight
35%11%30%16%41
744
16th to endNight
34%13%28%18%4
960
Page generated at 2017-09-22 07:35:38. Version ac04

Copyright 2017 A. Danko


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