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 2024-11-04.

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% 6% 2 6% 4 4 5% 4 6% 8% 42%	101097
	Night	13% 6% 2 6% 4 4 4 4 6% 8% 43%	97875
Transparency	Day	21% 46% 6% 12% 11% 4	104839
	Night	22% 46% 6% 10% 11% 5%	102272
Seeing	Day	14% 8% 21% 24% 21% 11%	15230
	Night	15% 6% 22% 32% 22% 3	25274

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 5% 3 3 4 4 7% 7% 45%	2836
	11th to 20th	Day	13% 5% 2 5% 4 3 3 3 4 7% 52%	2840
	21st to end	Day	19% 8% 2 5% 3 4 3 3 4 5% 43%	3124
February	1st to 10th	Day	15% 6% 3 6% 4 4 4 4 6% 8% 39%	1814
	11th to 20th	Day	19% 7% 2 5% 3 3 3 3 5% 5% 45%	1848
	21st to end	Day	18% 7% 2 5% 3 4 4 4 4 6% 43%	1579
March	1st to 10th	Day	21% 10% 3 7% 4 3 4 2 4 5% 37%	3435
	11th to 20th	Day	10% 4 2 6% 3 4 3 3 5% 7% 53%	3480
	21st to end	Day	19% 6% 2 6% 4 4 3 3 4 6% 42%	3815
April	1st to 10th	Day	10% 6% 2 5% 4 4 5% 3 5% 7% 50%	2090
	11th to 20th	Day	11% 6% 2 6% 4 3 5% 4 6% 7% 48%	2164
	21st to end	Day	7% 4 1 4 4 4 4 4 6% 9% 52%	2466
May	1st to 10th	Day	10% 6% 2 6% 4 5% 5% 4 7% 9% 43%	4082
	11th to 20th	Day	16% 7% 2 7% 4 4 4 4 6% 7% 38%	4081
	21st to end	Day	7% 4 2 5% 4 5% 5% 4 7% 10% 47%	4476
June	1st to 10th	Day	10% 7% 2 7% 5% 5% 6% 4 8% 11% 36%	2470
	11th to 20th	Day	6% 4 2 5% 4 6% 5% 5% 9% 11% 44%	2470
	21st to end	Day	5% 5% 1 6% 6% 6% 6% 6% 9% 11% 38%	2470
July	1st to 10th	Day	13% 7% 3 8% 6% 6% 6% 5% 8% 10% 28%	4120
	11th to 20th	Day	5% 5% 2 7% 6% 7% 7% 7% 9% 14% 31%	4120
	21st to end	Day	9% 7% 3 9% 6% 7% 7% 7% 11% 14% 21%	4466
August	1st to 10th	Day	16% 7% 2 8% 6% 5% 7% 6% 9% 11% 24%	4104
	11th to 20th	Day	9% 5% 2 7% 5% 5% 6% 6% 8% 12% 35%	4044
	21st to end	Day	7% 5% 2 5% 5% 5% 5% 4 7% 11% 46%	4072
September	1st to 10th	Day	8% 6% 2 7% 5% 5% 7% 4 7% 8% 41%	2090
	11th to 20th	Day	14% 6% 2 6% 4 4 5% 5% 6% 8% 40%	2090
	21st to end	Day	15% 7% 3 6% 5% 4 4 3 5% 6% 42%	2090
October	1st to 10th	Day	12% 6% 3 6% 4 3 4 4 4 5% 50%	2043
	11th to 20th	Day	10% 5% 1 4 3 3 2 2 5% 5% 59%	1900
	21st to end	Day	11% 4 2 5% 4 4 3 3 3 4 57%	2090
November	1st to 10th	Day	12% 6% 2 5% 4 3 3 3 4 5% 53%	1887
	11th to 20th	Day	14% 7% 2 3 2 3 3 3 4 6% 54%	1744
	21st to end	Day	15% 5% 3 5% 4 4 3 3 4 6% 48%	1710
December	1st to 10th	Day	19% 6% 2 6% 4 4 4 4 6% 7% 39%	1710
	11th to 20th	Day	16% 5% 2 5% 4 3 3 3 5% 6% 49%	2153
	21st to end	Day	20% 8% 2 5% 3 3 3 3 4 6% 42%	3124
January	1st to 10th	Night	18% 6% 2 5% 3 4 3 3 5% 7% 45%	4109
	11th to 20th	Night	10% 6% 2 6% 4 4 4 4 6% 7% 47%	4120
	21st to end	Night	19% 8% 3 6% 4 3 3 2 4 4 44%	4532
February	1st to 10th	Night	15% 7% 2 5% 4 3 4 3 5% 7% 43%	2361
	11th to 20th	Night	18% 7% 2 5% 4 4 3 3 4 5% 45%	2218
	21st to end	Night	14% 7% 2 6% 4 5% 3 3 5% 6% 45%	1875
March	1st to 10th	Night	23% 8% 3 6% 4 3 4 3 4 5% 37%	3418
	11th to 20th	Night	12% 4 2 3 3 3 4 3 6% 8% 51%	3480
	21st to end	Night	19% 5% 2 6% 4 3 4 4 6% 6% 42%	3817
April	1st to 10th	Night	11% 5% 1 5% 5% 4 5% 4 4 7% 50%	2090
	11th to 20th	Night	12% 4 1 5% 4 3 4 3 5% 7% 52%	1965
	21st to end	Night	8% 4 1 5% 4 4 4 4 5% 7% 53%	1728
May	1st to 10th	Night	10% 5% 2 6% 4 4 5% 4 7% 10% 42%	2813
	11th to 20th	Night	13% 6% 2 6% 4 4 4 4 6% 9% 42%	2812
	21st to end	Night	7% 4 2 5% 4 5% 5% 4 6% 8% 51%	3079
June	1st to 10th	Night	10% 8% 2 7% 5% 6% 6% 6% 7% 10% 33%	1710
	11th to 20th	Night	6% 6% 2 7% 5% 5% 6% 5% 7% 10% 42%	1710
	21st to end	Night	6% 5% 2 6% 6% 7% 6% 6% 10% 12% 35%	1710
July	1st to 10th	Night	16% 7% 3 8% 6% 5% 5% 5% 8% 10% 28%	2840
	11th to 20th	Night	7% 6% 2 7% 6% 7% 8% 6% 10% 13% 28%	2840
	21st to end	Night	12% 7% 3 9% 7% 7% 8% 7% 8% 10% 22%	3087
August	1st to 10th	Night	17% 7% 3 8% 6% 6% 7% 6% 8% 10% 22%	2825
	11th to 20th	Night	10% 6% 2 6% 5% 5% 7% 5% 7% 10% 36%	2785
	21st to end	Night	6% 5% 1 5% 4 4 5% 4 6% 11% 49%	3547
September	1st to 10th	Night	9% 6% 2 7% 5% 5% 5% 6% 7% 10% 38%	2090
	11th to 20th	Night	12% 6% 3 8% 5% 6% 4 4 5% 7% 40%	2090
	21st to end	Night	14% 5% 2 6% 4 5% 4 4 6% 7% 43%	2090
October	1st to 10th	Night	13% 5% 2 6% 4 4 3 2 4 7% 51%	2136
	11th to 20th	Night	12% 4 2 5% 3 2 3 3 4 5% 59%	2280
	21st to end	Night	10% 4 1 5% 3 3 4 3 4 6% 58%	2508
November	1st to 10th	Night	12% 5% 2 5% 3 3 3 2 5% 6% 56%	2264
	11th to 20th	Night	14% 7% 2 4 4 3 3 2 4 5% 52%	2432
	21st to end	Night	14% 5% 2 5% 3 3 4 4 4 7% 49%	2470
December	1st to 10th	Night	16% 6% 2 5% 4 3 4 3 6% 7% 44%	2470
	11th to 20th	Night	18% 5% 2 4 3 3 3 2 4 4 52%	3042
	21st to end	Night	19% 8% 2 6% 4 4 4 3 5% 6% 38%	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	27% 35% 2 15% 14% 7%	2837
	11th to 20th	Day	20% 36% 2 12% 21% 9%	2840
	21st to end	Day	28% 38% 1 11% 15% 7%	3124
February	1st to 10th	Day	15% 65% 3 8% 6% 2	1814
	11th to 20th	Day	16% 64% 2 7% 9% 2	1858
	21st to end	Day	18% 64% 2 4 7% 5%	1579
March	1st to 10th	Day	38% 40% 5% 7% 7% 4	3435
	11th to 20th	Day	17% 39% 4 10% 18% 11%	3480
	21st to end	Day	29% 39% 2 12% 14% 4	3815
April	1st to 10th	Day	13% 64% 4 7% 9% 3	2090
	11th to 20th	Day	16% 65% 4 7% 5% 3	2164
	21st to end	Day	11% 65% 3 11% 8% 2	2466
May	1st to 10th	Day	26% 39% 7% 19% 7% 1	4120
	11th to 20th	Day	30% 39% 5% 16% 10%	4085
	21st to end	Day	17% 38% 12% 13% 18% 2	4489
June	1st to 10th	Day	16% 66% 7% 7% 4 1	2470
	11th to 20th	Day	9% 66% 8% 11% 6% 1	2470
	21st to end	Day	13% 65% 8% 10% 4	2470
July	1st to 10th	Day	32% 40% 13% 14% 2	4055
	11th to 20th	Day	23% 43% 19% 15% 1	4051
	21st to end	Day	34% 43% 13% 7% 3	4324
August	1st to 10th	Day	37% 40% 14% 8% 1	4091
	11th to 20th	Day	20% 41% 10% 18% 11% 1	4083
	21st to end	Day	11% 38% 9% 29% 12% 1	4072
September	1st to 10th	Day	14% 61% 8% 8% 7% 2	2090
	11th to 20th	Day	18% 60% 5% 9% 7% 2	2090
	21st to end	Day	18% 60% 6% 8% 6% 1	2090
October	1st to 10th	Day	20% 37% 3 9% 24% 7%	3394
	11th to 20th	Day	6% 36% 2 8% 20% 28%	3140
	21st to end	Day	12% 36% 2 16% 23% 10%	3428
November	1st to 10th	Day	17% 57% 4 6% 11% 5%	1887
	11th to 20th	Day	17% 59% 2 9% 9% 4	1744
	21st to end	Day	14% 59% 4 10% 9% 4	1710
December	1st to 10th	Day	21% 59% 3 6% 7% 3	1710
	11th to 20th	Day	18% 47% 1 11% 18% 5%	2150
	21st to end	Day	31% 36% 4 12% 17% 1	3124
January	1st to 10th	Night	28% 35% 2 10% 17% 8%	4109
	11th to 20th	Night	23% 36% 2 15% 18% 6%	4120
	21st to end	Night	29% 38% 2 6% 18% 6%	4532
February	1st to 10th	Night	13% 64% 4 8% 9% 3	2361
	11th to 20th	Night	18% 63% 2 7% 8% 2	2219
	21st to end	Night	17% 64% 3 6% 5% 5%	1875
March	1st to 10th	Night	38% 40% 7% 9% 5% 2	3418
	11th to 20th	Night	19% 39% 2 8% 20% 12%	3480
	21st to end	Night	28% 39% 3 11% 11% 7%	3817
April	1st to 10th	Night	14% 64% 4 6% 7% 5%	2090
	11th to 20th	Night	15% 65% 3 8% 5% 4	1965
	21st to end	Night	11% 64% 4 11% 7% 2	1728
May	1st to 10th	Night	25% 40% 9% 17% 8% 1	2840
	11th to 20th	Night	26% 39% 7% 17% 11% 1	2813
	21st to end	Night	16% 39% 8% 17% 17% 3	3087
June	1st to 10th	Night	18% 66% 6% 6% 3 1	1710
	11th to 20th	Night	12% 65% 9% 8% 6% 1	1710
	21st to end	Night	12% 67% 9% 8% 4	1710
July	1st to 10th	Night	34% 40% 15% 10% 1	2795
	11th to 20th	Night	28% 44% 16% 11% 1	2786
	21st to end	Night	38% 42% 12% 5% 2	2988
August	1st to 10th	Night	40% 41% 12% 7% 1	2814
	11th to 20th	Night	22% 41% 14% 16% 6% 1	2812
	21st to end	Night	10% 37% 11% 28% 11% 1	3547
September	1st to 10th	Night	14% 61% 9% 8% 6% 2	2090
	11th to 20th	Night	19% 60% 4 9% 6% 1	2090
	21st to end	Night	17% 60% 7% 9% 6% 1	2090
October	1st to 10th	Night	22% 38% 5% 10% 20% 6%	3565
	11th to 20th	Night	7% 36% 2 8% 15% 32%	3779
	21st to end	Night	12% 36% 3 12% 23% 14%	4120
November	1st to 10th	Night	17% 57% 4 6% 11% 4	2264
	11th to 20th	Night	17% 59% 2 7% 10% 6%	2432
	21st to end	Night	14% 59% 3 9% 11% 4	2470
December	1st to 10th	Night	20% 59% 4 8% 7% 2	2470
	11th to 20th	Night	18% 48% 2 10% 18% 6%	3044
	21st to end	Night	33% 36% 3 12% 15% 1	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% 17% 29% 26% 13% 1	460
	11th to 20th	Day	14% 11% 27% 25% 18% 5%	452
	21st to end	Day	11% 10% 23% 27% 21% 8%	460
May	1st to 10th	Day	9% 12% 25% 27% 20% 7%	463
	11th to 20th	Day	14% 4 17% 30% 23% 13%	487
	21st to end	Day	15% 4 13% 25% 27% 17%	529
June	1st to 10th	Day	12% 3 12% 28% 29% 17%	490
	11th to 20th	Day	7% 3 14% 23% 26% 26%	490
	21st to end	Day	7% 2 12% 32% 25% 22%	490
July	1st to 10th	Day	9% 2 6% 20% 30% 32%	485
	11th to 20th	Day	8% 1 4 20% 37% 29%	484
	21st to end	Day	6% 2 7% 25% 36% 24%	532
August	1st to 10th	Day	12% 3 10% 23% 34% 19%	486
	11th to 20th	Day	12% 3 6% 21% 36% 23%	479
	21st to end	Day	12% 3 9% 24% 29% 23%	539
September	1st to 10th	Day	10% 4 9% 28% 30% 20%	490
	11th to 20th	Day	18% 3 11% 24% 31% 12%	490
	21st to end	Day	18% 2 16% 26% 26% 12%	490
October	1st to 10th	Day	16% 3 19% 32% 22% 8%	490
	11th to 20th	Day	10% 6% 20% 30% 24% 10%	490
	21st to end	Day	14% 7% 22% 29% 23% 5%	539
November	1st to 10th	Day	18% 4 24% 28% 19% 5%	467
	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% 33% 33% 11%	760
	11th to 20th	Night	14% 10% 28% 32% 16%	751
	21st to end	Night	10% 5% 24% 43% 18% 1	588
May	1st to 10th	Night	9% 5% 26% 39% 19% 1	570
	11th to 20th	Night	11% 3 22% 40% 20% 4	561
	21st to end	Night	12% 2 9% 36% 37% 4	617
June	1st to 10th	Night	14% 1 11% 36% 32% 5%	570
	11th to 20th	Night	8% 2 12% 30% 36% 12%	570
	21st to end	Night	8% 2 9% 31% 44% 6%	570
July	1st to 10th	Night	11% 3 5% 30% 42% 9%	555
	11th to 20th	Night	8% 2 3 26% 52% 8%	552
	21st to end	Night	8% 2 5% 33% 44% 8%	624
August	1st to 10th	Night	10% 2 7% 29% 44% 9%	567
	11th to 20th	Night	13% 3 4 30% 42% 8%	564
	21st to end	Night	13% 2 9% 27% 42% 8%	745
September	1st to 10th	Night	10% 2 9% 31% 41% 6%	760
	11th to 20th	Night	15% 3 10% 29% 39% 4	760
	21st to end	Night	16% 2 12% 32% 34% 4	760
October	1st to 10th	Night	15% 2 16% 35% 27% 5%	760
	11th to 20th	Night	13% 4 21% 34% 25% 4	760
	21st to end	Night	12% 5% 22% 35% 25% 2	836
November	1st to 10th	Night	13% 6% 22% 35% 21% 4	755
	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 2024-11-01 22:47:31. Version ac07

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