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 2025-05-11.

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 9% 5% 5% 5% 4 5% 7% 33%	113058
	Night	14% 11% 4 9% 5% 4 4 3 5% 6% 33%	115987
Transparency	Day	48% 7% 12% 20% 12% 1	116659
	Night	49% 6% 12% 21% 12% 1	120515
Seeing	Day	18% 11% 29% 22% 14% 6%	16099
	Night	19% 10% 29% 29% 12% 1	26286

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	11% 18% 7% 18% 5% 4 4 3 4 5% 22%	3617
	11th to 20th	Day	14% 16% 7% 18% 10% 9% 5% 3 4 4 10%	3620
	21st to end	Day	21% 19% 7% 13% 5% 4 5% 3 3 4 16%	4314
February	1st to 10th	Day	14% 14% 6% 13% 8% 5% 4 3 5% 5% 22%	1800
	11th to 20th	Day	14% 13% 6% 13% 9% 5% 4 3 4 5% 23%	1905
	21st to end	Day	14% 17% 5% 12% 5% 4 4 4 4 6% 25%	1650
March	1st to 10th	Day	15% 12% 5% 10% 6% 4 4 3 5% 6% 31%	4562
	11th to 20th	Day	12% 11% 4 8% 5% 4 4 4 5% 7% 34%	4980
	21st to end	Day	19% 14% 4 9% 5% 4 4 3 4 5% 29%	5465
April	1st to 10th	Day	17% 13% 3 8% 6% 4 5% 4 5% 6% 30%	2348
	11th to 20th	Day	16% 11% 3 7% 5% 5% 4 3 5% 7% 35%	2522
	21st to end	Day	16% 9% 3 8% 5% 4 4 3 5% 7% 35%	2600
May	1st to 10th	Day	18% 9% 2 7% 5% 5% 5% 4 5% 7% 35%	4212
	11th to 20th	Day	15% 8% 2 6% 5% 4 5% 4 6% 9% 35%	4081
	21st to end	Day	10% 6% 2 6% 5% 4 4 3 6% 9% 45%	4525
June	1st to 10th	Day	10% 6% 2 7% 5% 4 5% 4 6% 9% 41%	2660
	11th to 20th	Day	11% 6% 3 7% 5% 5% 5% 4 6% 9% 40%	2660
	21st to end	Day	10% 6% 2 6% 6% 5% 6% 5% 7% 10% 37%	2660
July	1st to 10th	Day	10% 6% 2 7% 5% 5% 6% 5% 7% 9% 37%	4440
	11th to 20th	Day	7% 4 2 5% 4 4 5% 5% 7% 9% 48%	4440
	21st to end	Day	8% 6% 2 6% 5% 6% 5% 5% 7% 9% 42%	4592
August	1st to 10th	Day	13% 5% 2 6% 5% 5% 5% 4 6% 8% 42%	4104
	11th to 20th	Day	11% 6% 2 7% 4 5% 5% 5% 7% 8% 40%	4044
	21st to end	Day	8% 5% 2 7% 5% 5% 6% 5% 7% 10% 40%	4449
September	1st to 10th	Day	10% 6% 3 7% 5% 5% 6% 4 6% 9% 40%	2161
	11th to 20th	Day	10% 5% 2 4 4 5% 4 4 6% 9% 47%	2090
	21st to end	Day	14% 7% 3 7% 5% 5% 5% 5% 7% 7% 36%	2090
October	1st to 10th	Day	14% 6% 2 8% 4 4 5% 4 4 6% 42%	2050
	11th to 20th	Day	16% 12% 3 8% 5% 5% 5% 3 5% 7% 33%	1900
	21st to end	Day	20% 12% 3 7% 5% 4 4 4 6% 7% 30%	1914
November	1st to 10th	Day	12% 10% 3 7% 6% 5% 5% 3 5% 7% 37%	1762
	11th to 20th	Day	15% 14% 5% 9% 5% 4 5% 3 5% 6% 29%	1800
	21st to end	Day	18% 14% 5% 11% 4 4 4 3 4 6% 26%	1736
December	1st to 10th	Day	13% 15% 8% 12% 7% 5% 5% 4 5% 5% 20%	2600
	11th to 20th	Day	18% 21% 7% 10% 6% 4 5% 3 4 5% 17%	2723
	21st to end	Day	25% 21% 7% 12% 4 3 3 3 3 4 14%	3982
January	1st to 10th	Night	13% 15% 6% 14% 6% 5% 4 3 4 5% 25%	6348
	11th to 20th	Night	11% 16% 7% 16% 9% 6% 6% 4 5% 5% 14%	6360
	21st to end	Night	18% 16% 9% 11% 5% 5% 5% 3 4 5% 21%	6646
February	1st to 10th	Night	16% 15% 5% 12% 7% 5% 5% 3 4 4 23%	2600
	11th to 20th	Night	14% 13% 5% 11% 7% 5% 4 4 5% 6% 26%	2378
	21st to end	Night	17% 12% 4 10% 6% 5% 4 4 5% 6% 28%	1980
March	1st to 10th	Night	15% 11% 4 9% 4 4 4 3 5% 6% 35%	5291
	11th to 20th	Night	10% 8% 3 6% 5% 4 5% 4 5% 7% 42%	4980
	21st to end	Night	17% 10% 3 8% 5% 4 4 3 4 6% 36%	5467
April	1st to 10th	Night	17% 10% 3 7% 5% 4 4 4 5% 6% 35%	2070
	11th to 20th	Night	18% 9% 3 6% 4 4 4 4 6% 6% 37%	1825
	21st to end	Night	16% 8% 3 6% 4 4 4 5% 5% 7% 38%	1800
May	1st to 10th	Night	16% 10% 3 6% 5% 4 4 4 5% 7% 36%	2903
	11th to 20th	Night	15% 8% 2 7% 4 3 4 3 4 6% 42%	2818
	21st to end	Night	10% 6% 2 5% 4 4 5% 3 5% 8% 48%	3028
June	1st to 10th	Night	12% 5% 2 6% 5% 4 3 3 5% 9% 47%	1520
	11th to 20th	Night	10% 6% 2 6% 4 3 4 5% 7% 8% 45%	1520
	21st to end	Night	10% 6% 2 5% 4 4 4 3 6% 9% 48%	1520
July	1st to 10th	Night	9% 4 1 5% 4 4 5% 4 7% 11% 46%	2530
	11th to 20th	Night	9% 4 1 5% 4 4 3 3 6% 8% 54%	2530
	21st to end	Night	6% 4 2 6% 5% 5% 5% 4 6% 9% 48%	2961
August	1st to 10th	Night	10% 6% 2 5% 4 3 4 4 6% 9% 47%	2825
	11th to 20th	Night	10% 6% 2 5% 3 4 4 4 5% 8% 49%	2785
	21st to end	Night	8% 6% 2 7% 4 4 5% 3 5% 7% 49%	3204
September	1st to 10th	Night	10% 7% 2 5% 4 3 4 4 5% 7% 49%	2000
	11th to 20th	Night	10% 4 2 4 4 3 3 4 4 7% 55%	2090
	21st to end	Night	14% 8% 2 6% 4 4 5% 3 5% 7% 43%	2090
October	1st to 10th	Night	14% 7% 2 5% 4 4 4 3 5% 6% 46%	2129
	11th to 20th	Night	18% 10% 3 7% 5% 4 4 3 4 5% 35%	2280
	21st to end	Night	20% 10% 3 7% 5% 4 4 3 5% 6% 32%	2679
November	1st to 10th	Night	13% 9% 3 7% 4 4 4 3 5% 6% 42%	2536
	11th to 20th	Night	15% 11% 4 8% 6% 5% 5% 4 5% 6% 30%	2600
	21st to end	Night	19% 15% 4 9% 4 4 4 4 4 6% 27%	2658
December	1st to 10th	Night	12% 14% 6% 16% 6% 5% 5% 4 5% 6% 21%	4580
	11th to 20th	Night	16% 20% 6% 12% 7% 4 4 3 5% 4 19%	5460
	21st to end	Night	25% 23% 7% 10% 4 3 3 2 3 4 14%	6996

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	64% 5% 11% 14% 6% 1	3618
	11th to 20th	Day	75% 8% 9% 5% 3	3620
	21st to end	Day	73% 5% 10% 9% 4	4314
February	1st to 10th	Day	63% 6% 9% 14% 8%	1800
	11th to 20th	Day	63% 5% 9% 15% 8% 1	1915
	21st to end	Day	59% 5% 10% 16% 7% 2	1650
March	1st to 10th	Day	54% 5% 13% 17% 9% 2	4562
	11th to 20th	Day	47% 6% 15% 22% 8% 2	4980
	21st to end	Day	57% 5% 10% 15% 11% 2	5465
April	1st to 10th	Day	53% 6% 11% 18% 11% 1	2348
	11th to 20th	Day	49% 5% 12% 20% 12% 2	2522
	21st to end	Day	47% 7% 13% 18% 14% 2	2600
May	1st to 10th	Day	47% 6% 12% 22% 11% 2	4250
	11th to 20th	Day	43% 10% 14% 23% 9% 1	4085
	21st to end	Day	36% 6% 12% 19% 24% 4	4538
June	1st to 10th	Day	37% 8% 13% 27% 13% 2	2660
	11th to 20th	Day	39% 7% 12% 23% 17% 2	2660
	21st to end	Day	38% 9% 13% 22% 16% 2	2660
July	1st to 10th	Day	40% 8% 15% 20% 15% 2	4371
	11th to 20th	Day	29% 7% 14% 32% 16% 1	4365
	21st to end	Day	36% 9% 14% 18% 21% 2	4447
August	1st to 10th	Day	37% 8% 13% 24% 16% 1	4091
	11th to 20th	Day	38% 8% 12% 29% 11% 1	4083
	21st to end	Day	36% 9% 13% 28% 12% 1	4448
September	1st to 10th	Day	40% 7% 14% 25% 13% 2	2161
	11th to 20th	Day	32% 8% 11% 32% 15% 1	2090
	21st to end	Day	44% 7% 12% 24% 13%	2090
October	1st to 10th	Day	32% 5% 11% 30% 20% 1	3401
	11th to 20th	Day	39% 6% 11% 25% 19%	3140
	21st to end	Day	45% 5% 14% 23% 12% 1	3126
November	1st to 10th	Day	46% 6% 12% 24% 12% 1	1762
	11th to 20th	Day	55% 5% 12% 19% 7% 2	1800
	21st to end	Day	59% 6% 12% 17% 6% 1	1736
December	1st to 10th	Day	63% 7% 15% 12% 3	2600
	11th to 20th	Day	69% 5% 9% 12% 4	2719
	21st to end	Day	76% 4 7% 8% 5%	3982
January	1st to 10th	Night	59% 6% 10% 18% 6% 2	6348
	11th to 20th	Night	67% 7% 11% 10% 5%	6360
	21st to end	Night	66% 5% 11% 12% 6%	6646
February	1st to 10th	Night	62% 6% 10% 14% 7% 1	2600
	11th to 20th	Night	57% 6% 10% 18% 9% 1	2379
	21st to end	Night	55% 5% 13% 17% 8% 1	1980
March	1st to 10th	Night	48% 5% 13% 22% 10% 1	5291
	11th to 20th	Night	38% 7% 14% 26% 15% 1	4980
	21st to end	Night	49% 6% 11% 20% 14% 2	5467
April	1st to 10th	Night	48% 5% 10% 21% 13% 2	2070
	11th to 20th	Night	45% 6% 11% 18% 18% 2	1825
	21st to end	Night	45% 6% 12% 18% 17% 2	1800
May	1st to 10th	Night	46% 6% 11% 20% 12% 4	2930
	11th to 20th	Night	41% 5% 12% 27% 13% 2	2819
	21st to end	Night	33% 8% 13% 21% 20% 5%	3036
June	1st to 10th	Night	34% 5% 11% 29% 18% 2	1520
	11th to 20th	Night	35% 7% 13% 26% 17% 2	1520
	21st to end	Night	33% 6% 13% 27% 19% 1	1520
July	1st to 10th	Night	32% 6% 13% 28% 15% 6%	2490
	11th to 20th	Night	27% 5% 14% 32% 21% 2	2482
	21st to end	Night	31% 8% 17% 19% 22% 2	2867
August	1st to 10th	Night	34% 7% 14% 28% 17% 1	2814
	11th to 20th	Night	33% 6% 11% 37% 11% 2	2812
	21st to end	Night	34% 7% 12% 32% 14% 1	3204
September	1st to 10th	Night	33% 8% 12% 28% 18% 2	2000
	11th to 20th	Night	29% 6% 10% 31% 22% 2	2090
	21st to end	Night	40% 5% 13% 27% 14% 1	2090
October	1st to 10th	Night	26% 4 10% 33% 27% 1	3558
	11th to 20th	Night	43% 5% 11% 24% 18%	3779
	21st to end	Night	40% 5% 11% 31% 13% 1	4405
November	1st to 10th	Night	42% 5% 11% 26% 14% 1	2536
	11th to 20th	Night	53% 5% 14% 18% 9% 1	2600
	21st to end	Night	58% 5% 12% 19% 6%	2658
December	1st to 10th	Night	61% 7% 15% 14% 3	4580
	11th to 20th	Night	66% 6% 9% 13% 5% 1	5463
	21st to end	Night	74% 5% 8% 7% 6%	6996

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	24% 17% 37% 15% 6% 1	300
	11th to 20th	Day	24% 15% 45% 13% 1 1	300
	21st to end	Day	28% 16% 35% 16% 4 1	330
February	1st to 10th	Day	24% 22% 37% 14% 2 1	300
	11th to 20th	Day	25% 21% 36% 15% 2	300
	21st to end	Day	29% 25% 33% 11% 2	249
March	1st to 10th	Day	25% 23% 35% 15% 3	330
	11th to 20th	Day	23% 14% 34% 22% 7%	500
	21st to end	Day	29% 14% 31% 20% 5% 1	550
April	1st to 10th	Day	23% 15% 36% 18% 9% 1	500
	11th to 20th	Day	25% 17% 32% 16% 6% 4	492
	21st to end	Day	24% 14% 29% 20% 11% 2	500
May	1st to 10th	Day	25% 12% 26% 22% 11% 3	503
	11th to 20th	Day	20% 10% 26% 22% 14% 7%	487
	21st to end	Day	14% 7% 22% 28% 18% 10%	552
June	1st to 10th	Day	11% 8% 30% 28% 18% 4	680
	11th to 20th	Day	13% 7% 30% 28% 18% 4	680
	21st to end	Day	12% 8% 29% 28% 17% 5%	680
July	1st to 10th	Day	9% 5% 24% 26% 24% 12%	671
	11th to 20th	Day	10% 6% 28% 28% 19% 9%	668
	21st to end	Day	8% 4 25% 31% 23% 9%	606
August	1st to 10th	Day	8% 4 19% 29% 24% 16%	486
	11th to 20th	Day	13% 4 17% 29% 23% 13%	479
	21st to end	Day	10% 4 21% 28% 24% 13%	539
September	1st to 10th	Day	12% 6% 23% 24% 22% 12%	490
	11th to 20th	Day	11% 3 19% 25% 27% 16%	490
	21st to end	Day	18% 9% 23% 23% 19% 8%	490
October	1st to 10th	Day	18% 7% 27% 23% 17% 8%	490
	11th to 20th	Day	20% 17% 26% 27% 8% 2	490
	21st to end	Day	28% 14% 36% 16% 5%	363
November	1st to 10th	Day	16% 19% 36% 18% 10% 1	300
	11th to 20th	Day	24% 20% 31% 18% 6% 1	300
	21st to end	Day	28% 18% 35% 16% 3	267
December	1st to 10th	Day	24% 18% 36% 14% 9% 1	200
	11th to 20th	Day	27% 22% 37% 10% 4	207
	21st to end	Day	27% 21% 37% 14% 1	330
January	1st to 10th	Night	21% 15% 36% 21% 5% 1	1000
	11th to 20th	Night	24% 13% 35% 22% 4 1	1000
	21st to end	Night	21% 12% 35% 27% 4	945
February	1st to 10th	Night	24% 12% 37% 23% 3	800
	11th to 20th	Night	23% 15% 34% 24% 4	783
	21st to end	Night	24% 14% 38% 21% 2	660
March	1st to 10th	Night	22% 13% 35% 25% 5% 1	800
	11th to 20th	Night	17% 16% 36% 25% 5% 1	800
	21st to end	Night	23% 11% 31% 27% 7% 1	880
April	1st to 10th	Night	21% 14% 34% 27% 4	670
	11th to 20th	Night	22% 9% 34% 26% 7% 1	593
	21st to end	Night	20% 9% 32% 31% 8%	600
May	1st to 10th	Night	19% 9% 31% 31% 8% 1	600
	11th to 20th	Night	20% 5% 28% 33% 13% 1	563
	21st to end	Night	12% 4 24% 38% 21% 2	617
June	1st to 10th	Night	13% 3 23% 47% 14% 1	570
	11th to 20th	Night	12% 4 24% 42% 18%	570
	21st to end	Night	12% 4 20% 44% 19% 1	570
July	1st to 10th	Night	8% 3 16% 40% 29% 4	555
	11th to 20th	Night	9% 3 19% 40% 24% 5%	552
	21st to end	Night	5% 2 18% 47% 25% 2	624
August	1st to 10th	Night	8% 3 16% 42% 29% 3	567
	11th to 20th	Night	9% 2 20% 36% 30% 4	564
	21st to end	Night	9% 2 16% 37% 31% 4	627
September	1st to 10th	Night	13% 4 19% 34% 26% 4	670
	11th to 20th	Night	11% 3 17% 33% 31% 5%	760
	21st to end	Night	15% 7% 20% 31% 21% 5%	760
October	1st to 10th	Night	18% 6% 27% 29% 18% 3	760
	11th to 20th	Night	22% 12% 29% 27% 8% 2	760
	21st to end	Night	26% 11% 34% 24% 5%	836
November	1st to 10th	Night	18% 11% 31% 28% 11% 1	780
	11th to 20th	Night	22% 14% 35% 21% 6% 1	800
	21st to end	Night	27% 13% 33% 21% 6%	800
December	1st to 10th	Night	23% 16% 33% 22% 6%	800
	11th to 20th	Night	23% 15% 36% 22% 3	950
	21st to end	Night	32% 11% 36% 19% 2	1100

Page generated at 2025-05-08 09:34:00. Version ac07

Copyright © 2025 Attilla Danko.