Augusta
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Augusta clear sky chart from 2005-11-06 to 2024-04-03.

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	12% 5% 2 5% 5% 3 5% 5% 6% 8% 43%	79233
	Night	13% 5% 2 5% 5% 3 5% 5% 6% 7% 45%	80907
Transparency	Day	27% 34% 7% 14% 14% 4	78956
	Night	27% 33% 7% 13% 15% 5%	80703
Seeing	Day	15% 8% 21% 24% 21% 11%	14370
	Night	15% 6% 22% 32% 22% 3	24538

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% 5% 2 4 4 2 4 5% 6% 7% 45%	2836
	11th to 20th	Day	13% 5% 2 4 4 2 3 3 4 7% 52%	2840
	21st to end	Day	19% 7% 3 5% 4 3 3 4 4 5% 43%	3124
February	1st to 10th	Day	16% 5% 3 6% 5% 3 5% 5% 6% 8% 39%	1814
	11th to 20th	Day	19% 6% 2 5% 4 2 3 3 4 5% 46%	1848
	21st to end	Day	18% 7% 2 4 4 3 4 5% 4 6% 43%	1579
March	1st to 10th	Day	14% 5% 2 5% 4 2 4 4 4 5% 50%	2090
	11th to 20th	Day	15% 5% 2 5% 5% 3 3 4 4 7% 45%	2090
	21st to end	Day	15% 6% 2 5% 5% 3 4 5% 4 7% 44%	2299
April	1st to 10th	Day	10% 5% 2 4 5% 3 5% 4 4 7% 50%	2002
	11th to 20th	Day	11% 6% 2 5% 5% 2 4 5% 5% 7% 47%	2048
	21st to end	Day	7% 3 1 4 4 3 4 5% 6% 9% 53%	2336
May	1st to 10th	Day	8% 5% 2 4 4 3 5% 5% 6% 8% 51%	2340
	11th to 20th	Day	11% 5% 2 5% 6% 4 5% 6% 7% 9% 39%	2301
	21st to end	Day	11% 5% 2 5% 6% 4 7% 5% 7% 10% 38%	2531
June	1st to 10th	Day	10% 6% 2 6% 6% 4 5% 6% 7% 11% 36%	2340
	11th to 20th	Day	7% 4 2 4 4 4 6% 6% 8% 11% 44%	2340
	21st to end	Day	5% 5% 2 5% 6% 5% 7% 8% 9% 12% 38%	2340
July	1st to 10th	Day	7% 6% 3 7% 7% 5% 7% 7% 8% 10% 33%	2340
	11th to 20th	Day	7% 6% 2 6% 8% 5% 7% 8% 8% 10% 33%	2340
	21st to end	Day	7% 4 3 6% 6% 5% 8% 8% 10% 13% 30%	2547
August	1st to 10th	Day	7% 6% 2 6% 7% 5% 7% 9% 10% 12% 29%	2327
	11th to 20th	Day	11% 5% 3 7% 7% 5% 7% 8% 8% 10% 30%	2303
	21st to end	Day	12% 7% 3 7% 8% 5% 7% 6% 7% 11% 28%	2324
September	1st to 10th	Day	8% 5% 2 6% 6% 4 7% 6% 7% 8% 41%	1980
	11th to 20th	Day	13% 5% 2 5% 6% 3 5% 6% 6% 8% 42%	1980
	21st to end	Day	15% 7% 3 5% 5% 3 5% 4 5% 6% 43%	1980
October	1st to 10th	Day	13% 6% 3 5% 4 2 3 5% 3 5% 51%	1936
	11th to 20th	Day	11% 5% 2 4 4 2 2 3 5% 6% 57%	1800
	21st to end	Day	12% 4 2 4 5% 3 3 4 3 4 56%	1980
November	1st to 10th	Day	12% 6% 3 4 4 2 3 3 4 6% 53%	1857
	11th to 20th	Day	14% 6% 2 3 2 2 3 3 4 6% 54%	1744
	21st to end	Day	15% 4 3 5% 4 3 4 4 4 6% 48%	1710
December	1st to 10th	Day	19% 5% 2 5% 4 3 4 5% 6% 7% 39%	1710
	11th to 20th	Day	16% 5% 2 4 5% 3 3 3 4 6% 49%	2153
	21st to end	Day	20% 8% 2 4 4 2 3 4 4 6% 42%	3124
January	1st to 10th	Night	18% 5% 2 4 4 2 3 4 5% 7% 45%	4109
	11th to 20th	Night	11% 6% 2 5% 5% 3 4 5% 6% 7% 47%	4120
	21st to end	Night	19% 7% 3 5% 5% 3 3 3 3 4 44%	4532
February	1st to 10th	Night	15% 6% 2 4 5% 2 4 5% 5% 7% 43%	2361
	11th to 20th	Night	18% 6% 2 5% 4 3 4 3 4 5% 45%	2218
	21st to end	Night	14% 6% 2 5% 5% 4 4 4 5% 7% 45%	1875
March	1st to 10th	Night	13% 5% 3 5% 4 2 4 4 4 5% 49%	2090
	11th to 20th	Night	14% 5% 2 3 5% 2 4 4 6% 7% 47%	2090
	21st to end	Night	13% 5% 2 5% 5% 3 5% 5% 6% 6% 45%	2299
April	1st to 10th	Night	11% 4 2 4 5% 3 5% 5% 5% 6% 51%	2003
	11th to 20th	Night	12% 4 2 5% 4 2 4 4 4 7% 52%	1861
	21st to end	Night	9% 3 2 4 5% 3 4 4 5% 7% 54%	1638
May	1st to 10th	Night	7% 4 2 4 5% 3 5% 5% 7% 8% 51%	1620
	11th to 20th	Night	8% 5% 2 5% 5% 5% 6% 6% 9% 11% 39%	1592
	21st to end	Night	10% 5% 2 5% 6% 4 6% 6% 7% 7% 42%	1744
June	1st to 10th	Night	10% 7% 3 6% 6% 3 7% 7% 7% 10% 34%	1620
	11th to 20th	Night	7% 5% 3 6% 5% 4 5% 7% 7% 11% 42%	1620
	21st to end	Night	6% 4 2 5% 6% 6% 6% 7% 10% 13% 35%	1620
July	1st to 10th	Night	8% 5% 3 6% 7% 4 6% 6% 9% 12% 34%	1620
	11th to 20th	Night	7% 6% 2 6% 7% 4 7% 7% 9% 14% 31%	1620
	21st to end	Night	6% 5% 3 6% 7% 4 8% 9% 8% 11% 33%	1771
August	1st to 10th	Night	7% 5% 3 6% 8% 4 8% 8% 10% 12% 30%	1611
	11th to 20th	Night	11% 6% 3 5% 6% 4 8% 6% 7% 12% 32%	1598
	21st to end	Night	11% 8% 3 6% 8% 4 6% 6% 6% 11% 33%	2009
September	1st to 10th	Night	8% 5% 2 6% 6% 4 5% 7% 7% 11% 39%	1980
	11th to 20th	Night	12% 6% 3 6% 6% 4 4 5% 5% 7% 41%	1980
	21st to end	Night	14% 5% 2 5% 5% 4 4 6% 6% 7% 42%	1980
October	1st to 10th	Night	13% 4 2 5% 5% 3 3 3 4 7% 51%	2023
	11th to 20th	Night	12% 4 2 4 4 1 3 3 4 5% 57%	2160
	21st to end	Night	11% 4 1 4 4 2 4 4 4 6% 56%	2376
November	1st to 10th	Night	12% 4 2 4 3 2 3 3 4 6% 56%	2221
	11th to 20th	Night	14% 5% 3 4 4 2 3 3 4 5% 52%	2432
	21st to end	Night	14% 5% 2 4 4 2 4 4 4 7% 50%	2470
December	1st to 10th	Night	17% 5% 2 4 5% 3 4 4 6% 7% 45%	2470
	11th to 20th	Night	18% 5% 2 4 3 2 3 3 4 4 52%	3042
	21st to end	Night	19% 8% 3 5% 5% 3 4 4 5% 6% 39%	4532

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	29% 23% 4 17% 19% 7%	2837
	11th to 20th	Day	24% 23% 3 16% 24% 10%	2840
	21st to end	Day	38% 21% 3 13% 17% 8%	3124
February	1st to 10th	Day	29% 33% 5% 11% 17% 5%	1814
	11th to 20th	Day	29% 34% 2 12% 18% 5%	1858
	21st to end	Day	27% 33% 5% 12% 16% 6%	1579
March	1st to 10th	Day	25% 33% 3 13% 16% 9%	2090
	11th to 20th	Day	27% 33% 8% 13% 12% 6%	2090
	21st to end	Day	29% 33% 7% 15% 14% 2	2299
April	1st to 10th	Day	24% 35% 6% 14% 16% 5%	2002
	11th to 20th	Day	20% 34% 4 16% 18% 8%	2048
	21st to end	Day	18% 36% 6% 19% 18% 3	2336
May	1st to 10th	Day	22% 35% 10% 18% 12% 3	2340
	11th to 20th	Day	29% 36% 11% 12% 11% 1	2305
	21st to end	Day	26% 36% 9% 17% 10% 1	2531
June	1st to 10th	Day	27% 36% 12% 15% 9%	2340
	11th to 20th	Day	25% 37% 10% 19% 8% 1	2340
	21st to end	Day	24% 37% 12% 15% 9% 3	2340
July	1st to 10th	Day	29% 38% 11% 12% 6% 4	2275
	11th to 20th	Day	30% 39% 12% 9% 6% 3	2271
	21st to end	Day	30% 39% 14% 14% 3	2405
August	1st to 10th	Day	26% 38% 12% 17% 6% 1	2314
	11th to 20th	Day	34% 36% 12% 14% 5%	2303
	21st to end	Day	38% 37% 9% 10% 6% 1	2324
September	1st to 10th	Day	28% 37% 9% 11% 10% 4	1980
	11th to 20th	Day	28% 36% 7% 11% 15% 3	1980
	21st to end	Day	28% 35% 4 12% 15% 6%	1980
October	1st to 10th	Day	24% 35% 3 13% 19% 8%	1936
	11th to 20th	Day	21% 35% 3 14% 21% 6%	1800
	21st to end	Day	23% 35% 2 10% 21% 8%	1980
November	1st to 10th	Day	19% 39% 3 11% 16% 13%	1857
	11th to 20th	Day	19% 38% 4 14% 17% 8%	1744
	21st to end	Day	26% 38% 4 13% 13% 7%	1710
December	1st to 10th	Day	25% 39% 6% 11% 15% 4	1710
	11th to 20th	Day	28% 30% 5% 15% 19% 4	2150
	21st to end	Day	33% 23% 4 15% 23% 3	3124
January	1st to 10th	Night	31% 23% 3 15% 21% 7%	4109
	11th to 20th	Night	29% 23% 3 19% 21% 6%	4120
	21st to end	Night	40% 22% 3 7% 21% 7%	4532
February	1st to 10th	Night	30% 33% 4 12% 14% 7%	2361
	11th to 20th	Night	28% 34% 3 11% 15% 8%	2219
	21st to end	Night	26% 33% 6% 12% 15% 8%	1875
March	1st to 10th	Night	26% 33% 4 11% 17% 8%	2090
	11th to 20th	Night	23% 34% 9% 13% 15% 6%	2090
	21st to end	Night	27% 33% 8% 14% 13% 5%	2299
April	1st to 10th	Night	22% 35% 6% 15% 15% 7%	2003
	11th to 20th	Night	20% 34% 5% 13% 20% 8%	1861
	21st to end	Night	20% 35% 7% 15% 18% 4	1638
May	1st to 10th	Night	22% 35% 11% 16% 12% 5%	1620
	11th to 20th	Night	25% 39% 12% 12% 12% 1	1593
	21st to end	Night	26% 37% 8% 16% 13% 1	1745
June	1st to 10th	Night	27% 36% 11% 17% 9%	1620
	11th to 20th	Night	25% 37% 11% 18% 8% 1	1620
	21st to end	Night	26% 38% 15% 9% 9% 3	1620
July	1st to 10th	Night	30% 38% 12% 8% 8% 3	1575
	11th to 20th	Night	27% 40% 15% 11% 5% 2	1566
	21st to end	Night	27% 41% 16% 13% 2	1672
August	1st to 10th	Night	26% 39% 15% 15% 5%	1600
	11th to 20th	Night	34% 36% 12% 13% 5% 1	1598
	21st to end	Night	36% 38% 11% 9% 6%	2009
September	1st to 10th	Night	28% 37% 11% 11% 8% 4	1980
	11th to 20th	Night	29% 36% 8% 11% 12% 3	1980
	21st to end	Night	29% 36% 4 11% 15% 5%	1980
October	1st to 10th	Night	24% 34% 3 10% 21% 7%	2023
	11th to 20th	Night	23% 34% 4 13% 18% 7%	2160
	21st to end	Night	22% 36% 2 13% 19% 9%	2376
November	1st to 10th	Night	16% 39% 4 11% 17% 14%	2221
	11th to 20th	Night	24% 38% 3 10% 16% 9%	2432
	21st to end	Night	24% 38% 5% 11% 15% 7%	2470
December	1st to 10th	Night	21% 39% 7% 13% 14% 5%	2470
	11th to 20th	Night	28% 30% 5% 12% 21% 4	3044
	21st to end	Night	35% 23% 3 16% 20% 3	4532

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	17% 20% 43% 17% 3	270
	11th to 20th	Day	20% 19% 32% 23% 6%	270
	21st to end	Day	21% 24% 36% 15% 4 1	297
February	1st to 10th	Day	21% 16% 40% 18% 5%	270
	11th to 20th	Day	29% 17% 37% 15% 2	270
	21st to end	Day	25% 19% 36% 15% 5%	234
March	1st to 10th	Day	18% 13% 32% 26% 10%	460
	11th to 20th	Day	17% 11% 41% 23% 8% 1	460
	21st to end	Day	19% 12% 38% 22% 9% 1	506
April	1st to 10th	Day	14% 15% 29% 27% 14% 1	428
	11th to 20th	Day	14% 12% 26% 24% 19% 6%	412
	21st to end	Day	11% 10% 23% 27% 21% 8%	420
May	1st to 10th	Day	9% 11% 25% 29% 19% 7%	423
	11th to 20th	Day	13% 4 15% 30% 25% 14%	447
	21st to end	Day	16% 3 12% 24% 27% 19%	485
June	1st to 10th	Day	12% 2 11% 27% 29% 18%	450
	11th to 20th	Day	8% 3 14% 22% 25% 27%	450
	21st to end	Day	7% 2 12% 30% 25% 23%	450
July	1st to 10th	Day	9% 2 6% 20% 30% 33%	445
	11th to 20th	Day	8% 1 5% 20% 37% 29%	444
	21st to end	Day	6% 2 7% 23% 36% 26%	488
August	1st to 10th	Day	11% 2 9% 23% 35% 21%	446
	11th to 20th	Day	13% 3 4 20% 37% 24%	439
	21st to end	Day	13% 3 9% 22% 29% 24%	495
September	1st to 10th	Day	9% 4 7% 28% 31% 21%	450
	11th to 20th	Day	16% 3 10% 25% 32% 13%	450
	21st to end	Day	18% 2 15% 27% 25% 13%	450
October	1st to 10th	Day	16% 3 19% 31% 23% 8%	450
	11th to 20th	Day	10% 5% 21% 28% 25% 11%	450
	21st to end	Day	14% 7% 23% 28% 22% 5%	495
November	1st to 10th	Day	19% 5% 24% 29% 19% 5%	455
	11th to 20th	Day	19% 9% 38% 22% 10% 2	304
	21st to end	Day	11% 13% 33% 26% 14% 2	270
December	1st to 10th	Day	25% 12% 34% 20% 8% 1	270
	11th to 20th	Day	20% 14% 40% 16% 9% 1	270
	21st to end	Day	29% 14% 31% 18% 6% 2	297
January	1st to 10th	Night	20% 11% 33% 29% 6%	760
	11th to 20th	Night	17% 10% 32% 33% 8%	760
	21st to end	Night	21% 9% 38% 28% 4	836
February	1st to 10th	Night	18% 9% 33% 33% 7%	760
	11th to 20th	Night	22% 10% 34% 31% 3	743
	21st to end	Night	17% 14% 35% 31% 3	628
March	1st to 10th	Night	16% 9% 33% 35% 7%	760
	11th to 20th	Night	15% 9% 36% 31% 9% 1	760
	21st to end	Night	16% 10% 34% 31% 9%	836
April	1st to 10th	Night	12% 11% 32% 33% 12%	729
	11th to 20th	Night	14% 9% 28% 32% 16%	711
	21st to end	Night	10% 5% 24% 42% 18% 1	558
May	1st to 10th	Night	9% 5% 26% 39% 19% 1	540
	11th to 20th	Night	10% 3 22% 40% 21% 4	531
	21st to end	Night	13% 2 9% 34% 39% 5%	584
June	1st to 10th	Night	15% 1 10% 36% 32% 5%	540
	11th to 20th	Night	8% 2 11% 31% 37% 12%	540
	21st to end	Night	8% 2 9% 30% 44% 6%	540
July	1st to 10th	Night	11% 2 5% 30% 42% 10%	525
	11th to 20th	Night	8% 2 3 26% 52% 8%	522
	21st to end	Night	7% 1 5% 33% 45% 8%	591
August	1st to 10th	Night	9% 2 5% 29% 45% 10%	537
	11th to 20th	Night	14% 3 3 30% 42% 8%	534
	21st to end	Night	13% 2 9% 27% 41% 8%	705
September	1st to 10th	Night	10% 2 7% 31% 43% 7%	720
	11th to 20th	Night	14% 2 10% 29% 41% 4	720
	21st to end	Night	15% 2 12% 32% 35% 4	720
October	1st to 10th	Night	15% 2 16% 35% 27% 6%	720
	11th to 20th	Night	13% 4 20% 34% 25% 4	720
	21st to end	Night	12% 5% 23% 34% 24% 2	792
November	1st to 10th	Night	13% 6% 22% 34% 21% 4	740
	11th to 20th	Night	17% 7% 28% 33% 14% 1	760
	21st to end	Night	16% 7% 26% 34% 17% 1	760
December	1st to 10th	Night	18% 7% 29% 34% 10% 1	760
	11th to 20th	Night	20% 6% 28% 33% 14% 1	760
	21st to end	Night	25% 9% 26% 31% 8%	836

Page generated at 2024-03-31 06:08:51. Version ac07

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