Auburn City Recreation Complex
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Auburn City Recreation Complex clear sky chart from 2005-11-06 to 2025-03-12.

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	11% 7% 3 7% 4 4 4 3 5% 7% 45%	108910
	Night	10% 7% 3 7% 4 4 4 3 5% 6% 49%	110282
Transparency	Day	37% 6% 13% 25% 17% 2	112574
	Night	35% 5% 12% 26% 19% 3	114745
Seeing	Day	14% 10% 30% 29% 15% 3	16139
	Night	13% 9% 33% 34% 11% 1	26204

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	10% 12% 4 12% 7% 5% 4 3 5% 6% 32%	4077
	11th to 20th	Day	7% 9% 4 8% 5% 6% 6% 3 5% 7% 41%	4080
	21st to end	Day	8% 11% 5% 11% 5% 5% 4 3 5% 7% 36%	4488
February	1st to 10th	Day	10% 13% 4 8% 6% 5% 5% 3 6% 7% 35%	1800
	11th to 20th	Day	10% 9% 4 8% 5% 4 4 3 5% 7% 39%	1784
	21st to end	Day	9% 8% 3 7% 5% 3 4 2 5% 7% 46%	1650
March	1st to 10th	Day	13% 9% 2 6% 4 3 4 3 4 5% 49%	3537
	11th to 20th	Day	11% 7% 3 6% 3 3 3 3 4 6% 50%	3491
	21st to end	Day	17% 11% 5% 8% 4 5% 4 4 5% 6% 31%	3814
April	1st to 10th	Day	15% 8% 2 5% 3 3 4 3 5% 5% 46%	2152
	11th to 20th	Day	15% 7% 3 6% 4 4 3 4 6% 7% 42%	2323
	21st to end	Day	21% 6% 2 5% 4 4 5% 3 4 6% 39%	2470
May	1st to 10th	Day	15% 8% 3 6% 5% 4 4 4 6% 7% 39%	4082
	11th to 20th	Day	16% 7% 3 7% 4 4 4 3 4 7% 43%	4082
	21st to end	Day	16% 5% 2 5% 4 4 4 4 6% 7% 42%	4540
June	1st to 10th	Day	7% 4 1 5% 5% 4 4 4 7% 9% 50%	2660
	11th to 20th	Day	8% 4 2 5% 5% 5% 4 4 6% 10% 47%	2660
	21st to end	Day	7% 4 1 6% 6% 5% 6% 4 7% 8% 46%	2644
July	1st to 10th	Day	12% 5% 2 6% 5% 4 5% 4 6% 8% 44%	4120
	11th to 20th	Day	7% 4 1 5% 4 3 4 4 6% 9% 53%	4120
	21st to end	Day	4 3 1 4 4 4 4 4 7% 10% 55%	4465
August	1st to 10th	Day	7% 4 2 5% 4 4 4 4 7% 11% 48%	4104
	11th to 20th	Day	13% 6% 2 6% 3 4 5% 4 6% 7% 45%	4041
	21st to end	Day	6% 4 2 6% 4 5% 5% 4 6% 8% 51%	4409
September	1st to 10th	Day	13% 4 2 4 3 3 4 3 5% 6% 54%	2219
	11th to 20th	Day	10% 5% 2 5% 3 3 3 4 4 8% 52%	2090
	21st to end	Day	12% 4 2 5% 3 3 3 3 4 5% 58%	2090
October	1st to 10th	Day	14% 5% 2 4 3 3 2 3 5% 6% 52%	1934
	11th to 20th	Day	11% 6% 2 4 2 2 3 2 4 4 58%	1900
	21st to end	Day	13% 7% 2 5% 3 3 3 2 4 6% 50%	2090
November	1st to 10th	Day	10% 6% 2 4 3 3 4 3 5% 6% 55%	1830
	11th to 20th	Day	11% 6% 2 6% 3 4 3 3 5% 5% 52%	1755
	21st to end	Day	13% 9% 3 5% 3 4 4 4 5% 7% 44%	1600
December	1st to 10th	Day	5% 4 2 6% 4 4 4 3 5% 6% 56%	2610
	11th to 20th	Day	9% 8% 3 9% 5% 4 4 3 5% 7% 43%	3008
	21st to end	Day	18% 11% 5% 14% 4 4 4 3 4 5% 28%	4191
January	1st to 10th	Night	10% 9% 5% 17% 7% 5% 4 3 5% 5% 29%	5888
	11th to 20th	Night	7% 7% 3 8% 4 5% 6% 4 5% 6% 45%	5900
	21st to end	Night	12% 11% 4 9% 4 4 4 3 4 5% 40%	6490
February	1st to 10th	Night	12% 10% 4 7% 5% 4 5% 3 4 5% 40%	2600
	11th to 20th	Night	10% 9% 3 8% 5% 3 4 4 5% 7% 43%	2519
	21st to end	Night	9% 7% 3 6% 4 4 3 3 4 6% 51%	1980
March	1st to 10th	Night	11% 6% 2 5% 3 3 3 3 4 6% 52%	3537
	11th to 20th	Night	11% 7% 2 4 2 2 2 3 4 5% 57%	3497
	21st to end	Night	18% 9% 3 8% 4 4 4 3 5% 7% 35%	3817
April	1st to 10th	Night	13% 6% 1 6% 4 3 4 4 5% 6% 48%	2028
	11th to 20th	Night	11% 8% 2 6% 4 3 4 3 5% 7% 46%	1803
	21st to end	Night	18% 7% 2 5% 3 3 3 4 4 7% 45%	1710
May	1st to 10th	Night	17% 6% 2 5% 4 3 4 4 5% 6% 45%	2823
	11th to 20th	Night	14% 6% 2 6% 3 3 3 2 4 7% 50%	2823
	21st to end	Night	14% 6% 2 6% 4 3 3 3 5% 7% 47%	3009
June	1st to 10th	Night	6% 4 2 5% 3 4 3 4 8% 8% 55%	1520
	11th to 20th	Night	7% 3 1 3 3 4 5% 4 8% 9% 52%	1520
	21st to end	Night	3 3 1 3 3 3 4 5% 5% 11% 58%	1529
July	1st to 10th	Night	8% 6% 2 6% 4 4 4 3 6% 7% 49%	2850
	11th to 20th	Night	4 3 2 5% 2 4 3 4 5% 8% 62%	2850
	21st to end	Night	4 2 1 4 3 4 4 4 7% 10% 56%	3098
August	1st to 10th	Night	3 3 1 5% 4 4 4 3 6% 10% 59%	2836
	11th to 20th	Night	13% 5% 1 5% 3 4 3 3 5% 7% 51%	2798
	21st to end	Night	6% 4 2 5% 3 3 3 3 5% 8% 59%	3252
September	1st to 10th	Night	9% 4 2 4 2 3 4 2 4 6% 60%	1957
	11th to 20th	Night	9% 3 1 4 3 3 5% 3 5% 6% 57%	2090
	21st to end	Night	9% 4 1 3 3 3 3 3 4 5% 62%	2090
October	1st to 10th	Night	11% 5% 2 5% 2 2 3 3 5% 7% 53%	2225
	11th to 20th	Night	12% 5% 1 4 3 3 2 3 3 5% 59%	2280
	21st to end	Night	13% 6% 2 5% 3 3 3 3 4 5% 53%	2508
November	1st to 10th	Night	8% 5% 1 4 4 3 3 3 5% 6% 58%	2468
	11th to 20th	Night	10% 6% 2 5% 4 4 3 3 5% 6% 54%	2640
	21st to end	Night	13% 7% 2 4 3 2 2 3 5% 5% 52%	2800
December	1st to 10th	Night	5% 5% 2 5% 4 4 4 3 5% 6% 57%	4580
	11th to 20th	Night	10% 8% 3 7% 4 4 3 3 5% 7% 47%	5199
	21st to end	Night	18% 13% 5% 10% 4 3 3 3 4 5% 33%	6768

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	52% 6% 10% 21% 9% 1	4078
	11th to 20th	Day	44% 5% 11% 21% 18% 2	4080
	21st to end	Day	46% 5% 14% 21% 14% 1	4488
February	1st to 10th	Day	48% 7% 14% 19% 10% 2	1800
	11th to 20th	Day	44% 6% 11% 23% 13% 3	1793
	21st to end	Day	38% 5% 13% 25% 16% 3	1650
March	1st to 10th	Day	37% 5% 10% 24% 20% 4	3537
	11th to 20th	Day	35% 6% 10% 27% 20% 1	3491
	21st to end	Day	51% 9% 18% 17% 4 1	3814
April	1st to 10th	Day	39% 6% 12% 25% 16% 2	2152
	11th to 20th	Day	41% 6% 13% 23% 15% 2	2323
	21st to end	Day	45% 7% 10% 25% 12% 1	2470
May	1st to 10th	Day	42% 7% 12% 24% 12% 3	4120
	11th to 20th	Day	41% 8% 10% 24% 17%	4086
	21st to end	Day	37% 8% 13% 26% 14% 2	4553
June	1st to 10th	Day	28% 9% 14% 31% 16% 2	2660
	11th to 20th	Day	31% 8% 15% 27% 17% 2	2660
	21st to end	Day	32% 10% 13% 27% 14% 4	2644
July	1st to 10th	Day	37% 6% 14% 27% 15% 2	4056
	11th to 20th	Day	27% 6% 12% 32% 19% 3	4051
	21st to end	Day	22% 7% 17% 31% 18% 4	4325
August	1st to 10th	Day	29% 8% 15% 27% 19% 2	4090
	11th to 20th	Day	37% 6% 16% 24% 16%	4080
	21st to end	Day	30% 6% 17% 26% 16% 6%	4408
September	1st to 10th	Day	30% 5% 12% 28% 20% 5%	2219
	11th to 20th	Day	31% 6% 11% 28% 22% 1	2090
	21st to end	Day	29% 4 10% 30% 25% 2	2090
October	1st to 10th	Day	21% 3 7% 19% 46% 5%	3207
	11th to 20th	Day	20% 3 8% 29% 31% 9%	3140
	21st to end	Day	31% 3 10% 29% 23% 3	3428
November	1st to 10th	Day	31% 4 13% 28% 20% 3	1830
	11th to 20th	Day	34% 5% 11% 27% 21% 2	1755
	21st to end	Day	38% 5% 13% 27% 16% 1	1600
December	1st to 10th	Day	29% 5% 17% 31% 18% 1	2610
	11th to 20th	Day	41% 4 16% 30% 10%	3005
	21st to end	Day	59% 4 12% 18% 6% 1	4191
January	1st to 10th	Night	54% 6% 11% 18% 10%	5888
	11th to 20th	Night	39% 5% 12% 24% 17% 3	5900
	21st to end	Night	47% 4 12% 18% 16% 3	6490
February	1st to 10th	Night	46% 5% 11% 20% 14% 3	2600
	11th to 20th	Night	40% 6% 13% 22% 16% 3	2520
	21st to end	Night	34% 5% 10% 24% 20% 6%	1980
March	1st to 10th	Night	32% 5% 10% 26% 23% 4	3537
	11th to 20th	Night	30% 4 9% 30% 21% 6%	3497
	21st to end	Night	48% 8% 20% 19% 5% 1	3817
April	1st to 10th	Night	35% 6% 10% 26% 20% 3	2028
	11th to 20th	Night	37% 7% 10% 27% 16% 3	1803
	21st to end	Night	39% 6% 11% 24% 18% 1	1710
May	1st to 10th	Night	39% 7% 11% 22% 18% 2	2850
	11th to 20th	Night	35% 7% 11% 24% 23% 1	2824
	21st to end	Night	36% 7% 13% 23% 19% 2	3017
June	1st to 10th	Night	24% 8% 15% 31% 17% 4	1520
	11th to 20th	Night	24% 9% 15% 30% 18% 4	1520
	21st to end	Night	20% 7% 16% 32% 22% 4	1529
July	1st to 10th	Night	34% 5% 14% 24% 20% 4	2805
	11th to 20th	Night	21% 5% 14% 34% 24% 3	2796
	21st to end	Night	20% 7% 17% 31% 23% 2	2999
August	1st to 10th	Night	21% 6% 16% 30% 24% 3	2826
	11th to 20th	Night	33% 5% 13% 29% 18% 1	2825
	21st to end	Night	25% 4 16% 30% 18% 8%	3252
September	1st to 10th	Night	25% 6% 12% 27% 23% 7%	1957
	11th to 20th	Night	26% 5% 11% 32% 22% 3	2090
	21st to end	Night	25% 5% 9% 28% 31% 3	2090
October	1st to 10th	Night	19% 3 8% 19% 45% 6%	3719
	11th to 20th	Night	20% 3 6% 31% 28% 11%	3779
	21st to end	Night	33% 3 8% 28% 25% 2	4120
November	1st to 10th	Night	27% 5% 13% 27% 24% 5%	2468
	11th to 20th	Night	31% 4 11% 29% 22% 3	2640
	21st to end	Night	35% 4 12% 28% 20% 2	2800
December	1st to 10th	Night	27% 5% 15% 35% 17% 1	4580
	11th to 20th	Night	38% 3 15% 30% 14% 1	5201
	21st to end	Night	55% 4 11% 22% 7% 1	6768

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	19% 15% 35% 23% 7% 1	300
	11th to 20th	Day	21% 17% 35% 21% 6%	300
	21st to end	Day	16% 10% 44% 25% 5%	330
February	1st to 10th	Day	17% 19% 42% 18% 4	300
	11th to 20th	Day	14% 17% 43% 19% 6% 1	300
	21st to end	Day	11% 20% 45% 20% 4	249
March	1st to 10th	Day	18% 16% 39% 23% 4	300
	11th to 20th	Day	28% 14% 32% 20% 5% 1	273
	21st to end	Day	27% 22% 33% 15% 3	297
April	1st to 10th	Day	22% 14% 39% 19% 6%	332
	11th to 20th	Day	19% 15% 37% 23% 6%	521
	21st to end	Day	23% 18% 29% 20% 9% 1	650
May	1st to 10th	Day	17% 12% 36% 25% 9% 1	653
	11th to 20th	Day	17% 10% 32% 28% 12% 1	675
	21st to end	Day	19% 7% 33% 26% 12% 3	734
June	1st to 10th	Day	5% 6% 22% 35% 25% 6%	680
	11th to 20th	Day	8% 5% 31% 34% 17% 5%	680
	21st to end	Day	6% 8% 36% 32% 16% 2	680
July	1st to 10th	Day	9% 6% 15% 33% 30% 7%	671
	11th to 20th	Day	5% 2 22% 41% 23% 7%	668
	21st to end	Day	5% 3 15% 42% 30% 5%	739
August	1st to 10th	Day	8% 2 19% 41% 26% 4	676
	11th to 20th	Day	9% 4 19% 39% 23% 5%	665
	21st to end	Day	10% 3 19% 32% 30% 6%	677
September	1st to 10th	Day	12% 3 22% 37% 19% 6%	429
	11th to 20th	Day	8% 1 27% 34% 24% 6%	300
	21st to end	Day	17% 4 31% 30% 18% 2	300
October	1st to 10th	Day	21% 8% 21% 29% 16% 6%	300
	11th to 20th	Day	8% 16% 42% 24% 7% 2	300
	21st to end	Day	15% 20% 34% 22% 7% 3	330
November	1st to 10th	Day	17% 12% 37% 22% 10% 2	300
	11th to 20th	Day	18% 15% 38% 22% 7% 1	300
	21st to end	Day	21% 12% 35% 24% 8% 1	300
December	1st to 10th	Day	9% 14% 42% 28% 6% 2	300
	11th to 20th	Day	17% 15% 33% 28% 7%	300
	21st to end	Day	21% 17% 38% 20% 3 1	330
January	1st to 10th	Night	12% 12% 38% 30% 8%	1000
	11th to 20th	Night	14% 14% 37% 28% 7%	1000
	21st to end	Night	15% 9% 42% 29% 5%	1100
February	1st to 10th	Night	17% 11% 42% 27% 4	1000
	11th to 20th	Night	14% 13% 39% 30% 4	965
	21st to end	Night	13% 12% 43% 25% 5%	660
March	1st to 10th	Night	13% 16% 37% 29% 6%	608
	11th to 20th	Night	19% 9% 37% 30% 4	575
	21st to end	Night	23% 12% 39% 21% 4	627
April	1st to 10th	Night	15% 16% 41% 23% 5%	570
	11th to 20th	Night	16% 13% 38% 28% 4	563
	21st to end	Night	21% 9% 36% 25% 8%	570
May	1st to 10th	Night	16% 11% 34% 31% 7%	570
	11th to 20th	Night	16% 7% 32% 35% 9% 1	561
	21st to end	Night	14% 6% 33% 32% 14%	617
June	1st to 10th	Night	7% 4 24% 44% 21% 1	570
	11th to 20th	Night	8% 3 30% 44% 16%	570
	21st to end	Night	5% 3 34% 45% 14%	570
July	1st to 10th	Night	7% 3 15% 44% 30% 1	555
	11th to 20th	Night	4 2 18% 50% 26% 1	552
	21st to end	Night	4 1 15% 52% 27% 1	624
August	1st to 10th	Night	5% 2 17% 50% 25% 2	567
	11th to 20th	Night	9% 2 16% 47% 24% 2	564
	21st to end	Night	6% 2 18% 44% 26% 3	627
September	1st to 10th	Night	10% 4 24% 38% 23% 2	570
	11th to 20th	Night	11% 2 24% 41% 21% 1	570
	21st to end	Night	9% 6% 28% 41% 14% 1	570
October	1st to 10th	Night	12% 8% 30% 34% 14% 2	705
	11th to 20th	Night	13% 10% 39% 31% 8%	760
	21st to end	Night	18% 10% 33% 32% 7%	836
November	1st to 10th	Night	10% 13% 29% 38% 10%	908
	11th to 20th	Night	12% 13% 39% 29% 7%	1000
	21st to end	Night	17% 11% 34% 29% 9%	1000
December	1st to 10th	Night	12% 13% 37% 32% 7%	1000
	11th to 20th	Night	18% 11% 34% 31% 7%	1000
	21st to end	Night	18% 14% 34% 29% 5%	1100

Page generated at 2025-03-09 07:08:46. Version ac07

Copyright © 2025 Attilla Danko.