Merchants Millpond State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Merchants Millpond State Park clear sky chart from 2005-11-05 to 2017-09-20.

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
40%
15551
21%
46953
12%
15514
50%
15514
26%
29516

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
27%
717
22%
2348
11%
716
42%
716
20%
1473
January16th to endNight
22%
768
23%
2496
8%
768
39%
768
23%
1562
February1st to 15thNight
23%
701
20%
2259
8%
701
39%
701
23%
1394
February16th to endNight
21%
631
27%
1893
11%
631
40%
631
26%
1122
March1st to 15thNight
28%
720
22%
2004
11%
720
41%
720
28%
1271
March16th to endNight
30%
768
20%
2082
11%
768
38%
768
26%
1385
April1st to 15thNight
27%
718
21%
1796
6%
718
37%
718
31%
1190
April16th to endNight
34%
720
20%
1800
7%
720
40%
720
32%
1173
May1st to 15thNight
36%
675
15%
1755
6%
675
40%
675
27%
1208
May16th to endNight
55%
414
19%
1537
17%
414
59%
414
26%
877
June1st to 15thNight
59%
360
16%
1440
18%
360
63%
360
23%
847
June16th to endNight
61%
360
17%
1440
17%
360
66%
360
24%
848
July1st to 15thNight
64%
409
13%
1429
13%
409
66%
409
24%
901
July16th to endNight
65%
564
16%
1595
11%
531
70%
531
32%
992
August1st to 15thNight
60%
593
14%
1663
10%
590
61%
590
27%
1107
August16th to endNight
62%
764
17%
1910
11%
764
63%
764
28%
1323
September1st to 15thNight
57%
720
23%
1800
14%
720
61%
720
32%
1192
September16th to endNight
46%
677
18%
1848
13%
677
51%
677
24%
1285
October1st to 15thNight
47%
660
27%
1980
22%
660
56%
660
28%
1246
October16th to endNight
40%
704
32%
2112
20%
704
56%
704
33%
1223
November1st to 15thNight
41%
700
24%
2185
17%
700
53%
700
30%
1294
November16th to endNight
40%
720
24%
2373
18%
720
51%
720
26%
1420
December1st to 15thNight
34%
720
20%
2520
12%
720
46%
720
21%
1557
December16th to endNight
29%
768
23%
2688
13%
768
45%
768
22%
1626

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
13%5%25%5%35%45%7%41%
47864
Night
13%5%25%42445%7%44%
47143
Cloud CoverDay
13%5%25%5%35%45%7%41%
47874
Night
13%5%2442445%7%43%
47147
TransparencyDay
41%6%11%21%16%3
47572
Night
38%5%11%21%17%4
46953
SeeingDay
16%9%24%25%17%5%
5851
Night
16%8%28%31%13%1
15558

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
16%7%23323436%44%
1587
16th to endDay
16%5%24423445%45%
1728
February1st to 15thDay
15%6%24434445%44%
1600
16th to endDay
15%425%32445%6%45%
1580
March1st to 15thDay
14%5%24423336%49%
1942
16th to endDay
19%5%24423335%43%
2142
April1st to 15thDay
11%5%2342335%7%50%
2152
16th to endDay
11%5%26%5%35%446%44%
2160
May1st to 15thDay
14%6%26%5%35%45%7%38%
2205
16th to endDay
11%5%25%5%35%5%6%8%40%
2575
June1st to 15thDay
9%415%5%47%6%7%8%39%
2520
16th to endDay
8%425%6%46%6%7%12%35%
2520
July1st to 15thDay
8%325%6%47%7%7%10%35%
2442
16th to endDay
5%6%36%7%5%7%6%7%11%31%
2465
August1st to 15thDay
12%6%27%7%46%6%6%10%31%
2274
16th to endDay
11%5%36%6%37%6%7%10%30%
2292
September1st to 15thDay
13%425%6%35%5%5%8%38%
2160
16th to endDay
21%7%36%6%35%435%29%
1878
October1st to 15thDay
18%7%25%422337%42%
1650
16th to endDay
12%41442333453%
1760
November1st to 15thDay
17%5%24314335%48%
1672
16th to endDay
14%423423337%50%
1584
December1st to 15thDay
14%5%25%423346%46%
1440
16th to endDay
19%5%3442345%442%
1536
January1st to 15thNight
14%6%25%42345%6%42%
2348
16th to endNight
16%6%35%424345%44%
2496
February1st to 15thNight
18%6%25%324336%44%
2258
16th to endNight
12%6%24323446%49%
1893
March1st to 15thNight
14%414425%346%47%
1992
16th to endNight
16%5%33434346%43%
2082
April1st to 15thNight
11%5%25%5%34446%47%
1796
16th to endNight
15%425%42335%6%46%
1800
May1st to 15thNight
12%6%25%4345%6%8%38%
1755
16th to endNight
10%32442445%11%45%
1535
June1st to 15thNight
9%5%24425%5%7%11%40%
1440
16th to endNight
6%415%5%35%5%7%12%41%
1440
July1st to 15thNight
7%426%5%46%6%9%9%37%
1515
16th to endNight
6%4245%36%6%9%12%37%
1703
August1st to 15thNight
8%6%37%6%345%5%9%39%
1674
16th to endNight
10%5%25%6%346%6%10%37%
1910
September1st to 15thNight
12%5%25%43446%8%43%
1800
16th to endNight
18%6%35%5%25%45%7%35%
1848
October1st to 15thNight
16%6%24323445%46%
1980
16th to endNight
11%414423336%54%
2112
November1st to 15thNight
16%414222336%50%
2185
16th to endNight
14%425%31445%6%47%
2373
December1st to 15thNight
14%7%25%42435%6%42%
2520
16th to endNight
16%7%23323347%43%
2688

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
16%7%23423446%44%
1587
16th to endDay
16%5%23423445%45%
1728
February1st to 15thDay
14%7%14434345%45%
1600
16th to endDay
15%425%32435%6%45%
1580
March1st to 15thDay
14%5%25%422335%49%
1953
16th to endDay
18%5%245%24245%43%
2141
April1st to 15thDay
11%5%24323347%51%
2152
16th to endDay
11%6%25%5%35%45%6%45%
2160
May1st to 15thDay
14%6%25%5%35%45%7%37%
2205
16th to endDay
11%5%25%5%35%5%5%8%40%
2575
June1st to 15thDay
9%4246%46%6%7%9%38%
2520
16th to endDay
8%5%25%6%46%6%7%12%35%
2520
July1st to 15thDay
8%425%6%47%7%7%11%35%
2442
16th to endDay
6%6%36%8%48%6%7%11%31%
2465
August1st to 15thDay
12%5%37%6%45%7%6%10%30%
2274
16th to endDay
12%5%27%6%46%6%7%10%29%
2292
September1st to 15thDay
13%5%25%5%35%5%5%8%38%
2160
16th to endDay
20%8%36%6%35%446%29%
1878
October1st to 15thDay
17%8%25%422336%42%
1650
16th to endDay
11%42442433453%
1760
November1st to 15thDay
17%5%14313335%48%
1672
16th to endDay
13%424423337%50%
1584
December1st to 15thDay
14%6%25%423446%46%
1440
16th to endDay
19%6%25%413445%42%
1536
January1st to 15thNight
14%6%2442345%6%43%
2348
16th to endNight
16%6%35%424346%44%
2496
February1st to 15thNight
17%6%24323446%44%
2251
16th to endNight
12%6%24423446%49%
1893
March1st to 15thNight
14%414425%346%47%
2004
16th to endNight
16%6%245%24347%43%
2082
April1st to 15thNight
11%5%245%24346%46%
1796
16th to endNight
15%5%2442245%6%46%
1800
May1st to 15thNight
12%6%25%5%25%47%7%39%
1754
16th to endNight
10%42442445%11%45%
1535
June1st to 15thNight
9%5%25%3346%7%11%40%
1440
16th to endNight
6%4245%35%5%7%11%42%
1440
July1st to 15thNight
6%5%25%6%46%6%9%11%36%
1515
16th to endNight
7%4245%36%6%9%12%37%
1703
August1st to 15thNight
8%7%28%6%245%5%9%39%
1674
16th to endNight
10%5%25%6%35%5%7%10%36%
1910
September1st to 15thNight
12%425%43446%8%43%
1800
16th to endNight
18%7%25%5%3435%7%36%
1848
October1st to 15thNight
16%5%2432435%446%
1980
16th to endNight
11%414323335%54%
2112
November1st to 15thNight
16%423412346%50%
2185
16th to endNight
14%425%323446%47%
2373
December1st to 15thNight
14%7%25%424447%41%
2520
16th to endNight
17%7%23423347%43%
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
40%48%20%20%5%
1588
16th to endDay
39%47%22%20%5%
1728
February1st to 15thDay
41%26%23%20%5%
1603
16th to endDay
38%410%22%19%4
1580
March1st to 15thDay
37%49%22%20%5%
1953
16th to endDay
43%49%19%19%4
2142
April1st to 15thDay
33%48%26%21%5%
2152
16th to endDay
38%6%11%18%18%7%
2160
May1st to 15thDay
44%6%13%21%12%2
2205
16th to endDay
40%6%13%25%12%1
2579
June1st to 15thDay
38%8%13%22%15%1
2520
16th to endDay
39%7%15%20%13%2
2520
July1st to 15thDay
38%10%16%20%10%2
2299
16th to endDay
41%10%14%20%11%2
2310
August1st to 15thDay
46%8%14%17%11%
2261
16th to endDay
45%9%13%18%11%1
2292
September1st to 15thDay
42%7%12%18%16%2
2160
16th to endDay
55%49%16%14%
1878
October1st to 15thDay
43%36%23%19%3
1650
16th to endDay
34%36%23%27%5%
1760
November1st to 15thDay
38%39%19%22%5%
1672
16th to endDay
36%39%22%21%6%
1584
December1st to 15thDay
39%311%22%17%5%
1440
16th to endDay
44%39%21%16%4
1536
January1st to 15thNight
41%5%8%18%19%6%
2348
16th to endNight
42%39%21%17%6%
2496
February1st to 15thNight
41%27%20%21%5%
2259
16th to endNight
35%39%25%19%6%
1893
March1st to 15thNight
37%5%11%22%17%5%
2004
16th to endNight
41%49%21%18%3
2082
April1st to 15thNight
37%410%19%20%5%
1796
16th to endNight
38%410%21%18%6%
1800
May1st to 15thNight
40%7%14%22%12%1
1755
16th to endNight
32%9%17%25%13%2
1537
June1st to 15thNight
36%9%15%25%12%1
1440
16th to endNight
33%11%16%21%14%2
1440
July1st to 15thNight
37%10%18%20%12%1
1429
16th to endNight
31%10%19%25%10%2
1595
August1st to 15thNight
39%7%19%19%12%
1663
16th to endNight
40%8%15%23%10%1
1910
September1st to 15thNight
37%7%16%17%16%3
1800
16th to endNight
46%5%10%16%18%1
1848
October1st to 15thNight
39%48%22%21%3
1980
16th to endNight
32%36%22%26%6%
2112
November1st to 15thNight
36%310%17%26%6%
2185
16th to endNight
37%47%22%20%7%
2373
December1st to 15thNight
42%411%19%18%4
2520
16th to endNight
40%311%22%16%4
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
24%23%40%10%1
86
16th to endDay
25%34%30%9%1
96
February1st to 15thDay
19%31%34%11%3
117
16th to endDay
17%17%40%19%5%
239
March1st to 15thDay
14%20%36%17%8%1
270
16th to endDay
19%13%37%18%9%2
288
April1st to 15thDay
18%12%35%17%11%3
270
16th to endDay
14%7%32%28%12%3
270
May1st to 15thDay
20%17%28%21%9%3
288
16th to endDay
17%420%29%21%6%
331
June1st to 15thDay
13%6%20%29%26%3
315
16th to endDay
11%6%23%32%21%4
315
July1st to 15thDay
11%116%36%27%5%
305
16th to endDay
8%112%37%27%11%
326
August1st to 15thDay
13%215%32%24%12%
313
16th to endDay
13%19%32%30%12%
332
September1st to 15thDay
16%5%19%24%19%15%
315
16th to endDay
30%116%20%21%9%
270
October1st to 15thDay
25%5%21%22%17%7%
255
16th to endDay
12%9%29%22%20%5%
272
November1st to 15thDay
19%10%26%26%14%3
250
16th to endDay
17%15%22%25%18%1
204
December1st to 15thDay
20%20%33%16%8%1
60
16th to endDay
31%17%21%21%7%
64
January1st to 15thNight
16%17%33%24%7%
720
16th to endNight
18%14%41%24%1
768
February1st to 15thNight
21%15%38%23%1
704
16th to endNight
16%19%39%21%3
631
March1st to 15thNight
17%13%36%26%5%
720
16th to endNight
19%11%34%26%7%
768
April1st to 15thNight
14%15%39%24%5%
718
16th to endNight
16%9%35%29%7%
720
May1st to 15thNight
14%10%34%32%8%
675
16th to endNight
11%422%44%17%
415
June1st to 15thNight
9%219%46%21%1
360
16th to endNight
6%123%50%18%
360
July1st to 15thNight
9%115%49%22%1
409
16th to endNight
9%114%40%30%3
564
August1st to 15thNight
11%112%42%27%3
593
16th to endNight
12%111%39%31%3
764
September1st to 15thNight
14%116%36%27%3
720
16th to endNight
21%317%32%23%1
677
October1st to 15thNight
18%423%29%20%3
660
16th to endNight
15%9%31%26%15%1
704
November1st to 15thNight
19%6%27%31%13%2
700
16th to endNight
16%11%28%27%14%1
720
December1st to 15thNight
18%10%30%30%9%
720
16th to endNight
20%13%32%27%5%
768
Page generated at 2017-09-21 07:18:20. Version ac04

Copyright 2017 A. Danko


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