GM Milford Proving Ground Softball Fields
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the GM Milford Proving Ground Softball Fields clear sky chart from 2005-11-06 to 2024-03-06.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	14% 10% 4 7% 6% 4 5% 5% 5% 7% 32%	78113
	Night	16% 11% 5% 7% 6% 3 5% 4 5% 6% 33%	81420
Transparency	Day	50% 7% 12% 19% 11% 1	77822
	Night	51% 6% 11% 20% 11% 1	81233
Seeing	Day	18% 11% 29% 23% 14% 6%	14483
	Night	19% 9% 29% 29% 12% 1	24712

By Month

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	16% 19% 8% 10% 6% 3 5% 4 5% 4 21%	2527
	11th to 20th	Day	16% 18% 7% 10% 11% 6% 6% 4 4 5% 13%	2530
	21st to end	Day	27% 20% 8% 10% 5% 2 3 3 3 4 14%	3011
February	1st to 10th	Day	14% 13% 6% 12% 9% 4 5% 4 5% 6% 22%	1710
	11th to 20th	Day	15% 12% 6% 12% 9% 4 4 4 4 5% 24%	1807
	21st to end	Day	14% 15% 6% 11% 6% 3 4 5% 4 6% 25%	1570
March	1st to 10th	Day	15% 11% 5% 8% 8% 3 5% 4 5% 6% 29%	1876
	11th to 20th	Day	12% 13% 6% 8% 6% 3 4 4 5% 6% 33%	1980
	21st to end	Day	20% 12% 4 8% 6% 3 4 4 4 5% 29%	2178
April	1st to 10th	Day	17% 12% 5% 7% 6% 3 5% 5% 5% 6% 29%	2112
	11th to 20th	Day	17% 10% 4 6% 6% 3 5% 4 5% 7% 34%	2266
	21st to end	Day	17% 9% 3 8% 6% 3 4 4 5% 7% 34%	2340
May	1st to 10th	Day	17% 8% 3 7% 7% 4 5% 5% 5% 6% 32%	2340
	11th to 20th	Day	18% 7% 3 5% 5% 3 5% 5% 5% 7% 35%	2301
	21st to end	Day	12% 7% 2 5% 5% 3 4 5% 6% 11% 39%	2552
June	1st to 10th	Day	10% 6% 3 6% 5% 3 5% 5% 6% 9% 42%	2520
	11th to 20th	Day	11% 5% 3 6% 6% 4 5% 5% 6% 9% 40%	2520
	21st to end	Day	10% 5% 2 5% 6% 3 6% 6% 7% 11% 37%	2520
July	1st to 10th	Day	7% 5% 2 4 5% 3 5% 5% 7% 9% 47%	2520
	11th to 20th	Day	9% 4 3 6% 6% 3 5% 6% 7% 9% 42%	2520
	21st to end	Day	7% 5% 2 5% 6% 4 6% 6% 7% 10% 42%	2617
August	1st to 10th	Day	9% 5% 2 5% 6% 4 6% 7% 6% 8% 41%	2327
	11th to 20th	Day	10% 5% 3 6% 6% 5% 5% 6% 7% 8% 37%	2303
	21st to end	Day	10% 5% 2 6% 6% 4 6% 5% 6% 9% 42%	2533
September	1st to 10th	Day	11% 6% 3 6% 6% 4 6% 5% 6% 9% 38%	2048
	11th to 20th	Day	10% 4 3 4 5% 4 4 5% 6% 9% 45%	1980
	21st to end	Day	13% 6% 3 6% 6% 3 5% 6% 8% 7% 37%	1980
October	1st to 10th	Day	15% 6% 3 7% 6% 4 5% 5% 4 6% 41%	1943
	11th to 20th	Day	17% 11% 3 7% 6% 3 5% 4 4 7% 32%	1800
	21st to end	Day	21% 11% 4 6% 6% 3 3 5% 5% 7% 29%	1814
November	1st to 10th	Day	13% 9% 4 6% 6% 5% 5% 4 5% 7% 37%	1672
	11th to 20th	Day	15% 12% 6% 7% 6% 3 4 4 5% 6% 30%	1710
	21st to end	Day	19% 13% 5% 9% 5% 3 4 4 4 6% 28%	1650
December	1st to 10th	Day	13% 15% 9% 12% 8% 3 5% 4 4 5% 22%	1520
	11th to 20th	Day	16% 15% 5% 11% 6% 3 6% 5% 5% 7% 21%	1733
	21st to end	Day	25% 21% 8% 11% 6% 3 4 4 3 4 11%	2783
January	1st to 10th	Night	16% 15% 7% 11% 7% 4 4 4 4 5% 23%	4428
	11th to 20th	Night	14% 17% 8% 13% 8% 5% 7% 5% 5% 5% 14%	4440
	21st to end	Night	24% 16% 9% 11% 6% 3 4 3 4 4 17%	4646
February	1st to 10th	Night	17% 14% 6% 10% 8% 4 6% 4 4 4 23%	2470
	11th to 20th	Night	14% 13% 6% 9% 8% 4 5% 5% 4 6% 27%	2256
	21st to end	Night	18% 12% 5% 8% 7% 3 4 4 5% 6% 28%	1884
March	1st to 10th	Night	16% 9% 4 8% 6% 4 4 4 5% 6% 35%	2201
	11th to 20th	Night	13% 10% 4 6% 5% 4 5% 4 5% 6% 39%	1980
	21st to end	Night	20% 8% 4 7% 5% 3 4 4 4 6% 34%	2178
April	1st to 10th	Night	16% 8% 5% 7% 5% 3 4 5% 5% 7% 36%	1864
	11th to 20th	Night	19% 9% 3 5% 4 3 4 5% 5% 7% 37%	1641
	21st to end	Night	17% 8% 4 5% 5% 3 4 5% 5% 6% 38%	1620
May	1st to 10th	Night	16% 9% 4 6% 6% 3 5% 5% 6% 7% 33%	1620
	11th to 20th	Night	18% 8% 2 5% 5% 2 5% 4 5% 7% 41%	1592
	21st to end	Night	10% 4 2 4 6% 3 6% 5% 5% 9% 45%	1719
June	1st to 10th	Night	12% 4 2 6% 5% 2 4 3 5% 9% 48%	1440
	11th to 20th	Night	11% 6% 2 6% 4 2 4 6% 6% 9% 45%	1440
	21st to end	Night	10% 5% 3 5% 4 3 4 4 6% 9% 48%	1440
July	1st to 10th	Night	8% 3 1 4 5% 3 4 5% 5% 10% 52%	1440
	11th to 20th	Night	8% 3 2 5% 5% 3 4 4 6% 8% 50%	1440
	21st to end	Night	6% 3 2 4 5% 3 5% 4 6% 9% 51%	1697
August	1st to 10th	Night	7% 5% 2 4 5% 2 5% 5% 7% 10% 47%	1611
	11th to 20th	Night	8% 4 2 5% 5% 3 4 5% 6% 9% 48%	1598
	21st to end	Night	8% 5% 2 5% 4 3 4 5% 5% 7% 52%	1820
September	1st to 10th	Night	10% 7% 2 4 5% 3 4 5% 5% 7% 47%	1894
	11th to 20th	Night	11% 4 2 3 4 2 3 5% 4 6% 54%	1980
	21st to end	Night	13% 7% 2 5% 5% 3 5% 4 5% 7% 44%	1980
October	1st to 10th	Night	15% 7% 3 5% 5% 3 4 4 5% 6% 44%	2016
	11th to 20th	Night	19% 10% 4 7% 6% 3 5% 4 4 6% 33%	2160
	21st to end	Night	21% 10% 3 6% 6% 4 4 4 4 6% 31%	2538
November	1st to 10th	Night	14% 8% 3 6% 4 3 5% 4 4 6% 42%	2406
	11th to 20th	Night	16% 10% 4 7% 7% 3 6% 5% 5% 6% 31%	2470
	21st to end	Night	20% 13% 5% 7% 4 3 4 5% 4 7% 28%	2525
December	1st to 10th	Night	17% 15% 7% 10% 7% 4 5% 4 5% 6% 20%	2660
	11th to 20th	Night	15% 14% 6% 11% 8% 4 5% 5% 5% 5% 23%	3442
	21st to end	Night	26% 23% 8% 9% 6% 3 3 3 3 4 12%	4884

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	65% 6% 11% 13% 5%	2528
	11th to 20th	Day	71% 9% 11% 7% 3	2530
	21st to end	Day	76% 5% 9% 7% 3 1	3011
February	1st to 10th	Day	63% 6% 9% 14% 8%	1710
	11th to 20th	Day	61% 5% 9% 15% 8% 1	1817
	21st to end	Day	59% 5% 11% 16% 6% 2	1570
March	1st to 10th	Day	54% 6% 13% 17% 8% 1	1876
	11th to 20th	Day	51% 5% 11% 19% 12% 3	1980
	21st to end	Day	58% 5% 9% 18% 8% 1	2178
April	1st to 10th	Day	54% 5% 11% 18% 11%	2112
	11th to 20th	Day	49% 5% 12% 19% 13% 2	2266
	21st to end	Day	49% 7% 14% 15% 14% 2	2340
May	1st to 10th	Day	51% 5% 12% 20% 10% 2	2340
	11th to 20th	Day	48% 7% 11% 19% 13% 2	2305
	21st to end	Day	41% 5% 15% 24% 14% 2	2552
June	1st to 10th	Day	37% 7% 13% 27% 13% 2	2520
	11th to 20th	Day	39% 8% 12% 23% 17% 2	2520
	21st to end	Day	37% 9% 14% 22% 16% 2	2520
July	1st to 10th	Day	32% 8% 12% 27% 18% 4	2451
	11th to 20th	Day	35% 8% 13% 24% 18% 2	2445
	21st to end	Day	35% 9% 13% 23% 18% 2	2472
August	1st to 10th	Day	37% 9% 14% 26% 12% 2	2314
	11th to 20th	Day	40% 9% 13% 23% 13% 2	2303
	21st to end	Day	37% 8% 10% 26% 17% 2	2533
September	1st to 10th	Day	41% 8% 14% 22% 12% 2	2048
	11th to 20th	Day	34% 8% 12% 33% 13% 1	1980
	21st to end	Day	42% 7% 12% 25% 13%	1980
October	1st to 10th	Day	43% 7% 11% 25% 13% 2	1943
	11th to 20th	Day	51% 7% 12% 19% 10% 1	1800
	21st to end	Day	54% 7% 13% 17% 9%	1814
November	1st to 10th	Day	46% 6% 12% 23% 13% 1	1672
	11th to 20th	Day	54% 5% 13% 19% 8% 2	1710
	21st to end	Day	57% 5% 12% 18% 7% 1	1650
December	1st to 10th	Day	64% 7% 10% 15% 4	1520
	11th to 20th	Day	62% 6% 13% 14% 5%	1729
	21st to end	Day	78% 5% 8% 6% 3	2783
January	1st to 10th	Night	62% 6% 11% 14% 6% 1	4428
	11th to 20th	Night	68% 8% 11% 9% 4	4440
	21st to end	Night	71% 5% 10% 11% 3 1	4646
February	1st to 10th	Night	62% 6% 10% 14% 7% 1	2470
	11th to 20th	Night	56% 6% 10% 18% 9% 1	2257
	21st to end	Night	56% 5% 12% 17% 8% 1	1884
March	1st to 10th	Night	50% 5% 12% 23% 10% 1	2201
	11th to 20th	Night	45% 6% 11% 20% 15% 2	1980
	21st to end	Night	52% 6% 9% 21% 11% 2	2178
April	1st to 10th	Night	47% 5% 11% 21% 14% 1	1864
	11th to 20th	Night	45% 6% 11% 17% 18% 2	1641
	21st to end	Night	45% 5% 12% 19% 16% 3	1620
May	1st to 10th	Night	49% 6% 12% 19% 11% 2	1620
	11th to 20th	Night	44% 5% 11% 19% 18% 3	1593
	21st to end	Night	35% 8% 14% 25% 15% 3	1720
June	1st to 10th	Night	35% 5% 12% 28% 18% 3	1440
	11th to 20th	Night	34% 8% 14% 26% 17% 2	1440
	21st to end	Night	33% 6% 13% 27% 19% 1	1440
July	1st to 10th	Night	29% 6% 12% 29% 21% 4	1400
	11th to 20th	Night	30% 5% 13% 30% 19% 2	1392
	21st to end	Night	27% 8% 18% 24% 20% 3	1603
August	1st to 10th	Night	30% 7% 15% 31% 16% 1	1600
	11th to 20th	Night	32% 8% 13% 32% 13% 3	1598
	21st to end	Night	30% 7% 13% 29% 19% 2	1820
September	1st to 10th	Night	34% 8% 12% 28% 16% 2	1894
	11th to 20th	Night	31% 6% 10% 31% 21% 1	1980
	21st to end	Night	38% 6% 13% 27% 15% 1	1980
October	1st to 10th	Night	41% 5% 10% 24% 19% 1	2016
	11th to 20th	Night	50% 6% 11% 20% 12% 1	2160
	21st to end	Night	53% 6% 10% 21% 9% 1	2538
November	1st to 10th	Night	42% 5% 11% 26% 14% 1	2406
	11th to 20th	Night	52% 5% 14% 19% 8% 1	2470
	21st to end	Night	56% 5% 13% 19% 7%	2525
December	1st to 10th	Night	64% 6% 11% 14% 6%	2660
	11th to 20th	Night	60% 7% 12% 14% 6% 1	3445
	21st to end	Night	76% 5% 10% 7% 2	4884

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	25% 17% 35% 16% 6% 1	270
	11th to 20th	Day	24% 13% 45% 14% 1 1	270
	21st to end	Day	30% 14% 34% 16% 5% 1	297
February	1st to 10th	Day	24% 21% 37% 15% 2 1	270
	11th to 20th	Day	25% 20% 37% 16% 2	270
	21st to end	Day	28% 27% 33% 11% 2	225
March	1st to 10th	Day	26% 22% 33% 16% 3	281
	11th to 20th	Day	21% 12% 35% 22% 8%	420
	21st to end	Day	29% 13% 31% 21% 6% 1	462
April	1st to 10th	Day	21% 13% 36% 20% 10% 1	420
	11th to 20th	Day	25% 17% 31% 16% 7% 5%	412
	21st to end	Day	25% 13% 29% 19% 11% 2	420
May	1st to 10th	Day	26% 10% 26% 23% 11% 4	423
	11th to 20th	Day	21% 10% 27% 21% 14% 7%	447
	21st to end	Day	15% 6% 22% 28% 19% 10%	506
June	1st to 10th	Day	11% 7% 31% 29% 18% 4	630
	11th to 20th	Day	14% 7% 29% 28% 18% 5%	630
	21st to end	Day	12% 7% 28% 29% 18% 5%	630
July	1st to 10th	Day	8% 4 23% 26% 26% 13%	621
	11th to 20th	Day	10% 6% 28% 28% 20% 8%	618
	21st to end	Day	8% 4 26% 30% 23% 9%	558
August	1st to 10th	Day	7% 3 18% 30% 24% 17%	446
	11th to 20th	Day	13% 4 17% 28% 24% 14%	439
	21st to end	Day	11% 4 22% 26% 24% 13%	495
September	1st to 10th	Day	14% 6% 22% 25% 22% 12%	450
	11th to 20th	Day	12% 3 20% 24% 26% 15%	450
	21st to end	Day	17% 8% 23% 24% 20% 9%	450
October	1st to 10th	Day	19% 6% 27% 22% 17% 9%	450
	11th to 20th	Day	20% 18% 26% 27% 8% 1	450
	21st to end	Day	29% 14% 36% 17% 4	329
November	1st to 10th	Day	16% 19% 36% 18% 10% 1	270
	11th to 20th	Day	23% 20% 32% 18% 6% 1	270
	21st to end	Day	28% 17% 35% 16% 4	241
December	1st to 10th	Day	25% 19% 34% 13% 8% 1	180
	11th to 20th	Day	26% 20% 39% 10% 4 1	186
	21st to end	Day	27% 20% 38% 14% 1	297
January	1st to 10th	Night	22% 15% 36% 22% 6% 1	950
	11th to 20th	Night	25% 13% 34% 23% 5% 1	950
	21st to end	Night	21% 11% 35% 28% 5%	898
February	1st to 10th	Night	25% 12% 37% 24% 3	760
	11th to 20th	Night	22% 15% 34% 25% 4	743
	21st to end	Night	25% 14% 37% 21% 2	628
March	1st to 10th	Night	21% 12% 34% 26% 6% 1	743
	11th to 20th	Night	18% 14% 36% 26% 5% 1	720
	21st to end	Night	23% 10% 31% 27% 8% 1	792
April	1st to 10th	Night	19% 13% 34% 28% 5%	604
	11th to 20th	Night	23% 8% 34% 27% 7% 2	533
	21st to end	Night	21% 8% 31% 31% 9%	540
May	1st to 10th	Night	19% 8% 31% 33% 8% 1	540
	11th to 20th	Night	21% 5% 27% 33% 13% 1	531
	21st to end	Night	13% 3 23% 38% 21% 2	584
June	1st to 10th	Night	12% 2 23% 48% 14% 1	540
	11th to 20th	Night	12% 4 24% 42% 19%	540
	21st to end	Night	11% 4 19% 45% 19% 1	540
July	1st to 10th	Night	8% 2 15% 40% 31% 4	525
	11th to 20th	Night	10% 2 18% 41% 24% 4	522
	21st to end	Night	5% 2 18% 47% 25% 2	591
August	1st to 10th	Night	8% 3 14% 42% 30% 3	537
	11th to 20th	Night	9% 2 19% 37% 30% 4	534
	21st to end	Night	10% 2 16% 37% 31% 4	594
September	1st to 10th	Night	13% 4 18% 34% 26% 4	634
	11th to 20th	Night	12% 4 18% 33% 29% 5%	720
	21st to end	Night	15% 7% 20% 31% 22% 6%	720
October	1st to 10th	Night	19% 5% 27% 29% 18% 3	720
	11th to 20th	Night	23% 12% 29% 27% 8% 2	720
	21st to end	Night	27% 11% 33% 24% 5%	792
November	1st to 10th	Night	18% 11% 31% 28% 11% 1	740
	11th to 20th	Night	22% 14% 35% 21% 7% 1	760
	21st to end	Night	27% 12% 33% 22% 6%	760
December	1st to 10th	Night	24% 16% 33% 21% 6%	760
	11th to 20th	Night	23% 14% 36% 23% 3	902
	21st to end	Night	32% 11% 35% 19% 2	1045

Page generated at 2024-03-03 06:28:53. Version ac07

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