Brady's Run Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Brady's Run Park clear sky chart from 2005-11-06 to 2024-07-03.

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	16% 11% 4 8% 5% 5% 5% 4 5% 7% 30%	89503
	Night	17% 12% 4 8% 5% 4 4 3 5% 6% 32%	89629
Transparency	Day	52% 6% 12% 19% 9% 1	89276
	Night	52% 6% 11% 19% 10% 1	89461
Seeing	Day	22% 15% 27% 20% 11% 4	14183
	Night	22% 12% 26% 27% 12% 1	23935

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	19% 22% 9% 11% 5% 4 4 2 4 5% 17%	2836
	11th to 20th	Day	14% 24% 8% 13% 7% 4 4 2 3 4 17%	2840
	21st to end	Day	26% 20% 7% 13% 5% 4 4 3 3 3 11%	3124
February	1st to 10th	Day	18% 19% 5% 10% 7% 5% 3 3 3 4 22%	1710
	11th to 20th	Day	17% 14% 5% 14% 6% 5% 4 4 5% 5% 21%	1663
	21st to end	Day	20% 16% 4 8% 6% 4 4 4 5% 5% 25%	1570
March	1st to 10th	Day	22% 11% 4 9% 4 4 4 3 5% 6% 27%	3435
	11th to 20th	Day	13% 10% 4 10% 6% 6% 5% 4 4 5% 33%	3480
	21st to end	Day	20% 10% 3 8% 5% 4 4 4 5% 7% 30%	3815
April	1st to 10th	Day	15% 12% 4 9% 5% 4 4 4 6% 6% 30%	2177
	11th to 20th	Day	17% 11% 4 7% 5% 4 4 4 5% 6% 33%	2314
	21st to end	Day	21% 10% 3 7% 5% 4 4 3 5% 6% 32%	2470
May	1st to 10th	Day	22% 9% 3 8% 5% 5% 5% 4 5% 6% 28%	4082
	11th to 20th	Day	19% 9% 3 8% 5% 4 4 4 6% 7% 31%	4081
	21st to end	Day	12% 6% 2 6% 5% 5% 5% 4 7% 9% 38%	4697
June	1st to 10th	Day	13% 7% 3 8% 5% 5% 6% 5% 6% 8% 34%	2660
	11th to 20th	Day	13% 7% 3 7% 5% 5% 5% 4 7% 9% 35%	2660
	21st to end	Day	13% 6% 2 6% 5% 5% 5% 4 7% 9% 37%	2660
July	1st to 10th	Day	10% 7% 3 8% 6% 5% 5% 4 6% 8% 39%	2458
	11th to 20th	Day	11% 7% 3 6% 5% 5% 5% 5% 7% 9% 36%	2340
	21st to end	Day	11% 6% 3 7% 6% 6% 6% 5% 7% 9% 35%	2547
August	1st to 10th	Day	9% 6% 3 7% 6% 7% 6% 5% 7% 9% 35%	2327
	11th to 20th	Day	12% 6% 3 9% 6% 5% 6% 6% 6% 9% 32%	2303
	21st to end	Day	10% 6% 2 8% 5% 6% 5% 5% 7% 9% 37%	2472
September	1st to 10th	Day	16% 6% 2 6% 4 4 4 3 5% 8% 42%	2146
	11th to 20th	Day	11% 5% 2 6% 5% 4 5% 4 7% 9% 41%	1980
	21st to end	Day	17% 7% 3 8% 6% 5% 4 4 5% 6% 37%	1980
October	1st to 10th	Day	15% 7% 2 6% 5% 4 5% 5% 6% 8% 37%	1811
	11th to 20th	Day	20% 8% 3 8% 5% 5% 5% 3 5% 5% 33%	1800
	21st to end	Day	22% 12% 3 7% 4 4 4 4 5% 6% 29%	1980
November	1st to 10th	Day	11% 9% 3 6% 5% 5% 6% 3 5% 5% 41%	1754
	11th to 20th	Day	17% 14% 4 8% 5% 4 4 3 4 6% 31%	1600
	21st to end	Day	17% 15% 6% 8% 6% 3 5% 4 5% 5% 25%	1520
December	1st to 10th	Day	20% 19% 6% 11% 6% 5% 4 3 4 4 17%	1520
	11th to 20th	Day	20% 16% 8% 13% 4 4 4 3 5% 5% 19%	1910
	21st to end	Day	25% 23% 7% 11% 5% 4 3 2 3 5% 12%	2781
January	1st to 10th	Night	16% 22% 8% 13% 5% 5% 4 3 4 4 17%	4109
	11th to 20th	Night	17% 18% 7% 15% 7% 6% 5% 3 4 4 15%	4120
	21st to end	Night	28% 17% 8% 11% 6% 4 3 2 3 3 16%	4532
February	1st to 10th	Night	20% 14% 6% 11% 5% 4 4 3 5% 5% 23%	2470
	11th to 20th	Night	19% 13% 5% 12% 6% 6% 4 3 4 5% 24%	2403
	21st to end	Night	20% 13% 5% 12% 5% 4 5% 4 4 4 24%	1881
March	1st to 10th	Night	24% 12% 3 7% 4 3 3 3 4 6% 32%	3418
	11th to 20th	Night	18% 12% 5% 8% 5% 3 3 3 4 6% 33%	3480
	21st to end	Night	17% 11% 3 7% 4 4 4 3 4 5% 38%	3817
April	1st to 10th	Night	17% 12% 3 6% 6% 4 3 3 5% 6% 34%	2001
	11th to 20th	Night	16% 9% 3 7% 4 5% 5% 3 5% 7% 35%	1832
	21st to end	Night	15% 9% 3 7% 4 4 4 3 6% 9% 35%	1710
May	1st to 10th	Night	26% 10% 3 6% 4 4 4 3 5% 7% 28%	2813
	11th to 20th	Night	16% 10% 3 8% 4 4 4 4 5% 7% 36%	2812
	21st to end	Night	10% 6% 3 5% 4 4 5% 4 7% 11% 42%	2840
June	1st to 10th	Night	9% 5% 3 6% 5% 5% 5% 5% 6% 9% 43%	1520
	11th to 20th	Night	11% 5% 3 7% 5% 4 3 3 6% 10% 43%	1520
	21st to end	Night	9% 4 2 7% 6% 4 5% 4 6% 9% 42%	1520
July	1st to 10th	Night	6% 7% 2 8% 5% 5% 5% 4 6% 8% 45%	1540
	11th to 20th	Night	8% 5% 2 5% 5% 5% 5% 4 7% 9% 46%	1620
	21st to end	Night	9% 6% 2 7% 5% 5% 4 5% 8% 9% 39%	1771
August	1st to 10th	Night	6% 6% 3 7% 4 4 5% 4 7% 9% 45%	1611
	11th to 20th	Night	9% 8% 2 7% 4 4 4 4 6% 8% 45%	1598
	21st to end	Night	10% 6% 2 6% 4 3 5% 4 7% 8% 45%	1864
September	1st to 10th	Night	12% 5% 2 5% 4 4 4 4 5% 7% 48%	1810
	11th to 20th	Night	10% 5% 2 4 3 3 4 3 7% 9% 51%	1980
	21st to end	Night	15% 7% 2 6% 4 4 4 3 6% 7% 41%	1980
October	1st to 10th	Night	14% 6% 2 6% 4 4 4 4 5% 7% 44%	2148
	11th to 20th	Night	18% 7% 2 8% 5% 3 5% 4 5% 6% 37%	2160
	21st to end	Night	24% 10% 3 6% 3 3 4 3 4 6% 34%	2376
November	1st to 10th	Night	14% 8% 2 6% 4 4 4 3 5% 6% 44%	2320
	11th to 20th	Night	18% 11% 3 7% 6% 4 4 4 5% 6% 31%	2578
	21st to end	Night	19% 13% 4 8% 4 4 3 4 5% 5% 29%	2660
December	1st to 10th	Night	22% 17% 7% 10% 5% 3 4 3 4 5% 20%	2660
	11th to 20th	Night	19% 19% 5% 10% 5% 4 3 3 4 5% 22%	3285
	21st to end	Night	26% 19% 6% 11% 6% 4 4 3 4 5% 13%	4870

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	70% 4 9% 12% 4	2837
	11th to 20th	Day	72% 3 7% 14% 3 1	2840
	21st to end	Day	78% 4 8% 7% 2	3124
February	1st to 10th	Day	67% 3 9% 14% 7%	1710
	11th to 20th	Day	64% 5% 9% 14% 7%	1672
	21st to end	Day	61% 4 12% 15% 7% 1	1570
March	1st to 10th	Day	57% 5% 10% 22% 6%	3435
	11th to 20th	Day	51% 6% 13% 22% 8% 1	3480
	21st to end	Day	52% 5% 11% 20% 11% 1	3815
April	1st to 10th	Day	53% 5% 11% 19% 11% 2	2177
	11th to 20th	Day	51% 6% 10% 17% 14% 2	2314
	21st to end	Day	52% 5% 10% 22% 10% 2	2470
May	1st to 10th	Day	55% 6% 10% 20% 8% 1	4120
	11th to 20th	Day	51% 7% 12% 21% 8% 1	4085
	21st to end	Day	39% 8% 15% 23% 12% 3	4711
June	1st to 10th	Day	45% 7% 13% 22% 11% 1	2660
	11th to 20th	Day	44% 7% 14% 22% 12% 1	2660
	21st to end	Day	41% 8% 12% 26% 12% 1	2660
July	1st to 10th	Day	42% 7% 13% 21% 14% 3	2393
	11th to 20th	Day	41% 7% 13% 24% 14% 1	2271
	21st to end	Day	41% 10% 13% 22% 13% 1	2405
August	1st to 10th	Day	42% 8% 15% 26% 9%	2314
	11th to 20th	Day	44% 8% 14% 23% 9% 1	2303
	21st to end	Day	41% 9% 12% 22% 13% 3	2472
September	1st to 10th	Day	40% 6% 11% 21% 18% 3	2146
	11th to 20th	Day	37% 6% 14% 27% 14% 1	1980
	21st to end	Day	47% 5% 11% 23% 14% 1	1980
October	1st to 10th	Day	42% 6% 13% 22% 16% 1	1811
	11th to 20th	Day	52% 5% 11% 21% 10%	1800
	21st to end	Day	55% 4 13% 17% 9% 1	1980
November	1st to 10th	Day	43% 5% 12% 21% 16% 2	1754
	11th to 20th	Day	54% 4 11% 18% 10% 2	1600
	21st to end	Day	59% 5% 12% 16% 6% 1	1520
December	1st to 10th	Day	70% 5% 10% 11% 3	1520
	11th to 20th	Day	67% 4 10% 16% 3	1906
	21st to end	Day	77% 3 10% 9% 2	2781
January	1st to 10th	Night	69% 5% 10% 13% 3	4109
	11th to 20th	Night	73% 5% 9% 11% 2	4120
	21st to end	Night	76% 3 7% 12% 3	4532
February	1st to 10th	Night	63% 4 10% 17% 6%	2470
	11th to 20th	Night	62% 4 10% 17% 7%	2405
	21st to end	Night	62% 5% 9% 14% 9% 1	1881
March	1st to 10th	Night	55% 4 10% 22% 8%	3418
	11th to 20th	Night	52% 5% 13% 23% 6% 1	3480
	21st to end	Night	47% 6% 11% 23% 13% 2	3817
April	1st to 10th	Night	51% 5% 10% 18% 13% 2	2001
	11th to 20th	Night	48% 5% 12% 17% 15% 3	1832
	21st to end	Night	45% 6% 12% 22% 13% 2	1710
May	1st to 10th	Night	55% 7% 8% 19% 10% 2	2840
	11th to 20th	Night	47% 7% 11% 24% 10% 2	2813
	21st to end	Night	33% 10% 14% 25% 14% 4	2847
June	1st to 10th	Night	36% 8% 14% 24% 17% 2	1520
	11th to 20th	Night	36% 8% 16% 23% 15% 2	1520
	21st to end	Night	37% 8% 13% 24% 16% 2	1520
July	1st to 10th	Night	36% 10% 11% 22% 17% 4	1496
	11th to 20th	Night	31% 8% 15% 25% 19% 2	1566
	21st to end	Night	38% 9% 16% 21% 13% 3	1672
August	1st to 10th	Night	33% 9% 15% 26% 17% 1	1600
	11th to 20th	Night	35% 8% 15% 26% 14% 2	1598
	21st to end	Night	33% 9% 13% 25% 15% 4	1864
September	1st to 10th	Night	34% 7% 11% 23% 19% 5%	1810
	11th to 20th	Night	29% 8% 14% 26% 22% 1	1980
	21st to end	Night	41% 6% 13% 22% 18% 1	1980
October	1st to 10th	Night	39% 7% 12% 24% 15% 2	2148
	11th to 20th	Night	47% 5% 12% 23% 12% 1	2160
	21st to end	Night	52% 5% 10% 21% 11% 2	2376
November	1st to 10th	Night	41% 4 12% 23% 16% 3	2320
	11th to 20th	Night	53% 4 11% 20% 10% 2	2578
	21st to end	Night	57% 4 12% 21% 6% 1	2660
December	1st to 10th	Night	67% 5% 11% 13% 4	2660
	11th to 20th	Night	64% 5% 12% 16% 3	3288
	21st to end	Night	74% 5% 10% 10% 2	4870

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	31% 28% 27% 10% 4 1	270
	11th to 20th	Day	33% 27% 30% 8% 1	270
	21st to end	Day	29% 29% 31% 8% 2 1	297
February	1st to 10th	Day	34% 20% 36% 9% 1	270
	11th to 20th	Day	35% 29% 29% 7%	270
	21st to end	Day	37% 26% 29% 8%	237
March	1st to 10th	Day	31% 20% 30% 16% 3	460
	11th to 20th	Day	32% 20% 30% 13% 5% 1	460
	21st to end	Day	33% 18% 28% 15% 4 1	506
April	1st to 10th	Day	29% 21% 26% 15% 8% 1	460
	11th to 20th	Day	26% 20% 27% 15% 8% 3	452
	21st to end	Day	29% 17% 31% 17% 6% 2	460
May	1st to 10th	Day	27% 19% 25% 18% 7% 3	463
	11th to 20th	Day	22% 15% 30% 20% 9% 4	487
	21st to end	Day	15% 8% 28% 26% 18% 6%	529
June	1st to 10th	Day	14% 14% 30% 25% 13% 4	490
	11th to 20th	Day	17% 12% 24% 29% 14% 4	490
	21st to end	Day	15% 10% 33% 27% 12% 3	490
July	1st to 10th	Day	13% 6% 22% 26% 22% 11%	453
	11th to 20th	Day	13% 6% 27% 28% 19% 8%	444
	21st to end	Day	14% 6% 24% 28% 19% 8%	488
August	1st to 10th	Day	11% 6% 22% 30% 20% 11%	446
	11th to 20th	Day	15% 5% 22% 28% 19% 10%	439
	21st to end	Day	12% 5% 24% 26% 20% 12%	495
September	1st to 10th	Day	18% 8% 21% 27% 19% 8%	450
	11th to 20th	Day	13% 5% 18% 31% 22% 10%	450
	21st to end	Day	19% 13% 24% 24% 16% 4	450
October	1st to 10th	Day	16% 10% 28% 25% 17% 5%	450
	11th to 20th	Day	23% 16% 30% 22% 7% 1	450
	21st to end	Day	30% 16% 31% 17% 6%	495
November	1st to 10th	Day	19% 19% 33% 16% 10% 3	352
	11th to 20th	Day	30% 18% 30% 13% 7% 1	218
	21st to end	Day	24% 23% 40% 12% 1	180
December	1st to 10th	Day	31% 27% 27% 9% 3 2	180
	11th to 20th	Day	29% 23% 33% 12% 2	180
	21st to end	Day	36% 23% 28% 12% 1	202
January	1st to 10th	Night	29% 21% 33% 14% 3	760
	11th to 20th	Night	30% 19% 32% 17% 2	760
	21st to end	Night	27% 22% 28% 20% 3	836
February	1st to 10th	Night	29% 18% 28% 23% 3	760
	11th to 20th	Night	30% 19% 34% 16% 1	743
	21st to end	Night	29% 19% 31% 19% 3	628
March	1st to 10th	Night	25% 18% 31% 23% 3	760
	11th to 20th	Night	26% 18% 27% 23% 5% 1	760
	21st to end	Night	24% 16% 32% 21% 6% 1	836
April	1st to 10th	Night	25% 16% 29% 24% 6%	760
	11th to 20th	Night	21% 13% 32% 24% 9% 1	708
	21st to end	Night	21% 9% 35% 29% 6%	570
May	1st to 10th	Night	21% 11% 25% 33% 8% 2	570
	11th to 20th	Night	20% 7% 27% 32% 13% 1	561
	21st to end	Night	12% 3 25% 36% 22% 3	481
June	1st to 10th	Night	11% 5% 25% 40% 19%	380
	11th to 20th	Night	13% 4 24% 39% 19% 1	380
	21st to end	Night	8% 5% 27% 36% 23% 1	380
July	1st to 10th	Night	8% 2 18% 41% 25% 7%	434
	11th to 20th	Night	8% 2 20% 36% 29% 5%	522
	21st to end	Night	11% 4 15% 42% 27% 2	591
August	1st to 10th	Night	10% 2 16% 39% 30% 3	537
	11th to 20th	Night	11% 3 13% 40% 28% 4	534
	21st to end	Night	12% 4 21% 30% 27% 6%	676
September	1st to 10th	Night	15% 4 18% 33% 26% 4	720
	11th to 20th	Night	12% 4 16% 34% 31% 4	720
	21st to end	Night	17% 8% 24% 26% 20% 4	720
October	1st to 10th	Night	18% 7% 24% 29% 21% 2	720
	11th to 20th	Night	22% 12% 30% 24% 10% 1	720
	21st to end	Night	30% 13% 25% 26% 7%	792
November	1st to 10th	Night	19% 11% 25% 31% 14%	740
	11th to 20th	Night	27% 16% 27% 21% 8% 1	760
	21st to end	Night	27% 17% 27% 22% 6%	760
December	1st to 10th	Night	33% 17% 27% 18% 5%	760
	11th to 20th	Night	29% 18% 28% 21% 4	760
	21st to end	Night	30% 18% 29% 21% 2	836

Page generated at 2024-06-29 22:08:51. Version ac07

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