Fall River State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fall River State Park clear sky chart from 2005-11-05 to 2017-09-19.

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
44%
15839
25%
46926
15%
15793
53%
15793
34%
27066

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
35%
899
29%
2327
11%
895
47%
895
38%
1371
January16th to endNight
33%
960
30%
2496
11%
960
46%
960
39%
1466
February1st to 15thNight
30%
880
21%
2288
7%
876
38%
876
30%
1469
February16th to endNight
31%
626
27%
1888
11%
626
44%
626
31%
1088
March1st to 15thNight
34%
540
23%
1980
13%
540
47%
540
25%
1136
March16th to endNight
29%
576
16%
2112
10%
576
38%
576
21%
1311
April1st to 15thNight
33%
539
22%
1905
13%
539
48%
539
28%
1041
April16th to endNight
31%
540
20%
1665
14%
540
42%
540
26%
1045
May1st to 15thNight
37%
540
21%
1620
14%
540
47%
540
30%
1002
May16th to endNight
47%
563
19%
1684
17%
561
53%
561
31%
1026
June1st to 15thNight
59%
540
18%
1620
12%
540
64%
540
38%
914
June16th to endNight
57%
540
22%
1620
14%
540
64%
540
46%
827
July1st to 15thNight
67%
510
19%
1530
17%
510
69%
510
40%
841
July16th to endNight
76%
564
25%
1594
27%
531
77%
531
40%
872
August1st to 15thNight
76%
539
24%
1610
28%
536
78%
536
40%
891
August16th to endNight
74%
573
26%
1782
29%
573
76%
573
41%
947
September1st to 15thNight
60%
540
25%
1938
27%
540
64%
540
31%
1057
September16th to endNight
61%
504
30%
1857
28%
504
69%
504
36%
928
October1st to 15thNight
46%
612
29%
1932
22%
612
52%
612
33%
1105
October16th to endNight
41%
704
33%
2112
15%
704
54%
704
45%
1054
November1st to 15thNight
41%
790
31%
2190
15%
790
53%
790
41%
1211
November16th to endNight
35%
900
28%
2340
11%
900
46%
900
36%
1415
December1st to 15thNight
34%
900
24%
2340
10%
900
43%
900
33%
1470
December16th to endNight
35%
960
27%
2496
12%
960
46%
960
32%
1579

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
9%4143217%345%41%
47888
Night
8%4133217%345%45%
47122
Cloud CoverDay
11%5%24424447%48%
47886
Night
9%42432335%7%52%
47122
TransparencyDay
35%5%13%25%16%3
47586
Night
31%412%26%20%4
46927
SeeingDay
11%6%25%29%21%5%
5850
Night
12%8%30%33%14%1
15840

By Month

Percentage Cloud Cover SW (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
7%5%134218%33444%
1611
16th to endDay
9%4143219%235%42%
1728
February1st to 15thDay
8%6%26%3218%335%39%
1583
16th to endDay
9%6%243218%33441%
1586
March1st to 15thDay
10%7%25%4219%33336%
1980
16th to endDay
15%6%244219%23434%
2112
April1st to 15thDay
11%5%244219%336%37%
2043
16th to endDay
15%7%25%4219%23431%
2292
May1st to 15thDay
12%4145%220%33436%
2331
16th to endDay
11%5%15%5%321%35%6%30%
2430
June1st to 15thDay
6%3134220%447%40%
2340
16th to endDay
3122220%448%48%
2340
July1st to 15thDay
6%3133221%45%6%41%
2340
16th to endDay
42133221%5%6%6%40%
2466
August1st to 15thDay
7%3144312%5%5%7%45%
2340
16th to endDay
6%3133112%35%7%50%
2420
September1st to 15thDay
12%5%144211%446%43%
2019
16th to endDay
6%4143212%445%50%
1848
October1st to 15thDay
10%4144211%245%47%
1686
16th to endDay
7%4133212%345%52%
1760
November1st to 15thDay
5%3123117%335%51%
1665
16th to endDay
10%4122118%12449%
1620
December1st to 15thDay
13%5%243219%335%37%
1620
16th to endDay
10%7%15%3118%23438%
1728
January1st to 15thNight
7%4122219%235%46%
2327
16th to endNight
7%4143219%22448%
2496
February1st to 15thNight
8%7%243218%32442%
2278
16th to endNight
7%5%233118%335%45%
1888
March1st to 15thNight
10%4144219%33440%
1980
16th to endNight
13%5%133119%33438%
2112
April1st to 15thNight
8%4133119%245%43%
1905
16th to endNight
12%5%144219%33437%
1665
May1st to 15thNight
11%3133119%246%42%
1619
16th to endNight
9%3134219%348%38%
1683
June1st to 15thNight
43123220%447%45%
1620
16th to endNight
2122219%448%50%
1620
July1st to 15thNight
5%3133220%348%43%
1620
16th to endNight
31133221%46%7%42%
1702
August1st to 15thNight
3223313%5%6%8%49%
1620
16th to endNight
43123212%348%54%
1782
September1st to 15thNight
9%3143111%346%49%
1938
16th to endNight
6%3132212%36%6%50%
1857
October1st to 15thNight
13%3143211%23449%
1932
16th to endNight
6%2122111%235%58%
2112
November1st to 15thNight
5%3122117%335%52%
2190
16th to endNight
10%4122119%33347%
2340
December1st to 15thNight
11%5%232119%345%40%
2340
16th to endNight
11%5%133219%235%41%
2496

Percentage Cloud Cover SE (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
9%6%2443343453%
1611
16th to endDay
12%5%25%423246%50%
1728
February1st to 15thDay
10%7%37%423336%46%
1583
16th to endDay
10%7%35%323346%48%
1586
March1st to 15thDay
13%7%35%425%445%43%
1980
16th to endDay
20%8%35%424335%39%
2110
April1st to 15thDay
13%6%25%424347%45%
2043
16th to endDay
17%9%36%5%22335%40%
2292
May1st to 15thDay
16%6%25%5%34446%39%
2331
16th to endDay
14%6%25%6%35%46%8%36%
2430
June1st to 15thDay
8%424425%45%9%47%
2340
16th to endDay
6%212325%46%9%54%
2340
July1st to 15thDay
8%224435%5%6%9%46%
2340
16th to endDay
5%324435%6%6%8%49%
2466
August1st to 15thDay
7%3245%25%5%6%8%48%
2340
16th to endDay
8%3143245%48%53%
2420
September1st to 15thDay
13%425%424447%47%
2019
16th to endDay
8%423323437%55%
1848
October1st to 15thDay
11%5%24423336%52%
1686
16th to endDay
9%413323346%56%
1760
November1st to 15thDay
6%41232345%6%58%
1665
16th to endDay
12%5%13312225%58%
1620
December1st to 15thDay
14%7%24323337%46%
1620
16th to endDay
14%8%35%423346%44%
1728
January1st to 15thNight
9%5%23323246%55%
2327
16th to endNight
7%5%24322345%57%
2496
February1st to 15thNight
9%7%35%424336%48%
2278
16th to endNight
9%5%24323446%53%
1888
March1st to 15thNight
11%5%235%2445%7%48%
1980
16th to endNight
17%6%24423436%44%
2112
April1st to 15thNight
10%41432335%7%51%
1905
16th to endNight
14%6%25%5%23345%46%
1665
May1st to 15thNight
16%41431335%8%47%
1619
16th to endNight
11%5%2342445%10%46%
1683
June1st to 15thNight
4423225%5%5%8%53%
1620
16th to endNight
41133235%7%9%57%
1620
July1st to 15thNight
6%41432346%10%51%
1620
16th to endNight
5%2144345%7%10%51%
1702
August1st to 15thNight
4312335%6%7%8%53%
1620
16th to endNight
5%22332445%9%56%
1782
September1st to 15thNight
10%314423446%52%
1938
16th to endNight
7%31332447%6%56%
1857
October1st to 15thNight
14%41432333454%
1932
16th to endNight
7%312312346%63%
2112
November1st to 15thNight
7%413313346%60%
2190
16th to endNight
11%5%2331333456%
2340
December1st to 15thNight
13%6%2422235%7%49%
2340
16th to endNight
13%6%34323247%48%
2496

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
33%411%27%20%1
1612
16th to endDay
35%313%28%16%2
1728
February1st to 15thDay
39%5%13%28%9%3
1584
16th to endDay
36%5%11%27%15%3
1586
March1st to 15thDay
43%49%22%15%3
1980
16th to endDay
48%410%23%11%1
2112
April1st to 15thDay
39%415%24%15%1
2043
16th to endDay
46%39%24%13%1
2292
May1st to 15thDay
45%5%11%20%15%1
2331
16th to endDay
44%7%14%21%11%1
2434
June1st to 15thDay
33%7%14%25%17%2
2340
16th to endDay
24%7%15%28%21%3
2340
July1st to 15thDay
30%8%14%28%15%1
2201
16th to endDay
26%8%16%29%16%1
2311
August1st to 15thDay
30%8%17%24%17%2
2326
16th to endDay
29%6%13%28%14%7%
2420
September1st to 15thDay
37%6%12%21%16%6%
2019
16th to endDay
29%411%26%23%3
1848
October1st to 15thDay
32%413%23%21%4
1686
16th to endDay
28%413%25%22%5%
1760
November1st to 15thDay
25%411%29%21%7%
1665
16th to endDay
29%211%29%24%2
1620
December1st to 15thDay
39%411%29%14%
1620
16th to endDay
41%412%24%14%3
1728
January1st to 15thNight
30%210%30%21%3
2327
16th to endNight
29%313%29%19%4
2496
February1st to 15thNight
38%413%25%15%3
2288
16th to endNight
32%412%28%17%4
1888
March1st to 15thNight
35%5%10%22%18%6%
1980
16th to endNight
42%412%21%16%2
2112
April1st to 15thNight
32%411%25%22%4
1905
16th to endNight
39%5%12%20%17%3
1665
May1st to 15thNight
36%5%14%23%17%2
1620
16th to endNight
33%7%18%24%14%1
1685
June1st to 15thNight
27%7%15%30%18%1
1620
16th to endNight
20%6%15%31%21%4
1620
July1st to 15thNight
27%413%30%20%3
1530
16th to endNight
25%7%13%27%24%1
1594
August1st to 15thNight
24%8%13%31%16%5%
1610
16th to endNight
24%7%13%26%22%7%
1782
September1st to 15thNight
31%5%11%24%18%9%
1938
16th to endNight
26%5%11%25%27%4
1857
October1st to 15thNight
34%38%19%24%8%
1932
16th to endNight
21%39%30%28%6%
2112
November1st to 15thNight
26%310%25%24%9%
2190
16th to endNight
31%48%27%24%4
2340
December1st to 15thNight
35%313%29%17%
2340
16th to endNight
36%313%25%14%6%
2496

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%13%30%22%8%
90
16th to endDay
13%16%43%18%6%1
96
February1st to 15thDay
7%23%41%21%6%
90
16th to endDay
6%22%40%25%31
81
March1st to 15thDay
20%26%38%11%3
90
16th to endDay
26%9%40%14%9%
96
April1st to 15thDay
16%14%32%28%8%
162
16th to endDay
22%11%36%20%6%1
402
May1st to 15thDay
16%10%33%26%11%2
468
16th to endDay
16%10%32%25%12%2
517
June1st to 15thDay
9%326%36%19%4
495
16th to endDay
6%325%38%22%4
495
July1st to 15thDay
8%119%35%28%6%
475
16th to endDay
5%7%31%44%10%
515
August1st to 15thDay
7%111%32%38%8%
493
16th to endDay
8%115%31%35%7%
460
September1st to 15thDay
8%12%32%36%10%
174
16th to endDay
12%125%29%18%14%
99
October1st to 15thDay
5%5%26%31%17%13%
90
16th to endDay
6%242%37%8%3
96
November1st to 15thDay
7%428%25%26%6%
90
16th to endDay
30%17%30%18%21
90
December1st to 15thDay
15%11%45%15%8%3
90
16th to endDay
20%14%32%27%5%
96
January1st to 15thNight
13%12%36%29%8%
900
16th to endNight
10%11%39%31%6%
960
February1st to 15thNight
13%13%37%32%3
880
16th to endNight
12%13%37%30%5%
626
March1st to 15thNight
12%10%38%31%6%
540
16th to endNight
19%11%38%26%4
576
April1st to 15thNight
12%14%37%28%6%
539
16th to endNight
17%8%39%25%7%
540
May1st to 15thNight
17%5%36%29%10%
540
16th to endNight
12%430%32%17%2
563
June1st to 15thNight
6%324%42%22%
540
16th to endNight
5%130%43%18%
540
July1st to 15thNight
7%116%48%24%1
510
16th to endNight
5%7%42%40%3
564
August1st to 15thNight
5%19%45%36%1
539
16th to endNight
6%11%39%38%3
573
September1st to 15thNight
11%119%38%27%2
540
16th to endNight
8%319%36%24%5%
504
October1st to 15thNight
16%428%28%18%2
612
16th to endNight
9%8%37%30%12%
704
November1st to 15thNight
10%10%34%30%12%1
790
16th to endNight
15%12%33%29%8%
900
December1st to 15thNight
17%9%34%31%5%
900
16th to endNight
17%9%33%32%6%
960
Page generated at 2017-09-20 03:49:51. Version ac04

Copyright 2017 A. Danko


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