Takhini Hot Springs
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Takhini Hot Springs clear sky chart from 2005-11-06 to 2025-06-10.

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	8% 12% 4 11% 7% 7% 6% 5% 7% 8% 25%	122833
	Night	5% 12% 5% 12% 8% 7% 7% 5% 7% 8% 24%	124017
Transparency	Day	52% 10% 16% 16% 6%	122528
	Night	52% 11% 14% 15% 7% 1	123966
Seeing	Day	14% 11% 23% 28% 18% 6%	17855
	Night	10% 7% 24% 34% 22% 4	24120

By Month

Percentage Cloud Cover NW (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	1 7% 4 15% 11% 11% 9% 7% 8% 8% 20%	2000
	11th to 20th	Day	2 10% 6% 15% 8% 8% 8% 6% 7% 9% 22%	2428
	21st to end	Day	3 15% 6% 14% 9% 6% 7% 4 7% 8% 22%	3010
February	1st to 10th	Day	2 12% 6% 12% 9% 10% 7% 5% 7% 8% 22%	1400
	11th to 20th	Day	3 16% 6% 12% 8% 8% 5% 5% 8% 8% 23%	1557
	21st to end	Day	1 12% 5% 15% 11% 8% 6% 5% 7% 6% 24%	1460
March	1st to 10th	Day	1 8% 3 13% 10% 10% 7% 5% 8% 6% 28%	4402
	11th to 20th	Day	2 12% 6% 14% 10% 8% 6% 5% 7% 7% 23%	4733
	21st to end	Day	2 9% 5% 12% 7% 6% 6% 5% 8% 10% 30%	5910
April	1st to 10th	Day	3 12% 5% 15% 7% 6% 7% 5% 7% 9% 23%	2430
	11th to 20th	Day	3 13% 5% 11% 8% 7% 5% 5% 6% 8% 28%	2766
	21st to end	Day	5% 13% 5% 13% 8% 6% 6% 5% 7% 7% 25%	2800
May	1st to 10th	Day	9% 17% 4 10% 6% 5% 5% 4 6% 7% 27%	7157
	11th to 20th	Day	6% 15% 5% 12% 7% 6% 7% 5% 7% 7% 22%	7193
	21st to end	Day	7% 10% 3 9% 7% 7% 6% 5% 7% 8% 29%	8380
June	1st to 10th	Day	12% 11% 4 10% 8% 6% 7% 4 7% 8% 25%	3588
	11th to 20th	Day	13% 12% 4 11% 8% 6% 5% 4 6% 8% 23%	3420
	21st to end	Day	9% 9% 4 10% 9% 7% 7% 5% 8% 8% 24%	3420
July	1st to 10th	Day	10% 7% 3 8% 7% 7% 7% 5% 8% 9% 30%	5700
	11th to 20th	Day	17% 9% 3 10% 7% 7% 7% 5% 7% 7% 19%	5447
	21st to end	Day	13% 9% 4 9% 6% 6% 6% 5% 7% 8% 27%	5486
August	1st to 10th	Day	9% 6% 2 7% 5% 5% 4 4 6% 7% 45%	4953
	11th to 20th	Day	16% 10% 3 7% 5% 5% 4 4 5% 7% 33%	4414
	21st to end	Day	18% 11% 3 9% 6% 5% 6% 5% 7% 8% 22%	4873
September	1st to 10th	Day	16% 13% 4 11% 6% 5% 5% 4 6% 6% 24%	2327
	11th to 20th	Day	11% 10% 4 9% 6% 5% 6% 4 7% 7% 29%	2280
	21st to end	Day	13% 15% 5% 10% 7% 6% 6% 5% 5% 7% 22%	2021
October	1st to 10th	Day	9% 17% 5% 13% 7% 7% 7% 5% 7% 6% 17%	3170
	11th to 20th	Day	8% 15% 6% 14% 6% 5% 5% 4 6% 9% 23%	2804
	21st to end	Day	9% 17% 6% 14% 7% 6% 6% 5% 7% 7% 16%	2737
November	1st to 10th	Day	5% 17% 7% 15% 11% 7% 8% 5% 5% 6% 15%	1372
	11th to 20th	Day	4 17% 8% 18% 13% 8% 6% 4 6% 5% 12%	1200
	21st to end	Day	2 15% 5% 16% 11% 9% 8% 7% 8% 5% 13%	1073
December	1st to 10th	Day	5% 13% 5% 13% 9% 7% 8% 6% 8% 9% 18%	1440
	11th to 20th	Day	2 9% 4 14% 12% 8% 10% 6% 7% 10% 18%	1502
	21st to end	Day	6% 12% 4 14% 11% 10% 9% 7% 8% 7% 11%	1980
January	1st to 10th	Night	3 11% 4 13% 11% 11% 10% 6% 7% 7% 17%	7990
	11th to 20th	Night	2 12% 6% 14% 8% 6% 6% 5% 9% 12% 20%	7470
	21st to end	Night	5% 14% 5% 12% 9% 8% 6% 5% 6% 7% 22%	7945
February	1st to 10th	Night	3 11% 5% 13% 10% 8% 8% 5% 7% 8% 22%	3000
	11th to 20th	Night	2 13% 5% 14% 9% 8% 8% 5% 7% 7% 22%	2729
	21st to end	Night	3 12% 6% 11% 10% 6% 7% 6% 6% 8% 26%	2169
March	1st to 10th	Night	1 8% 3 13% 10% 11% 8% 6% 7% 8% 25%	5472
	11th to 20th	Night	4 12% 6% 14% 10% 8% 7% 5% 6% 7% 21%	5236
	21st to end	Night	2 10% 5% 14% 7% 6% 6% 4 7% 7% 31%	5041
April	1st to 10th	Night	1 11% 5% 12% 7% 6% 7% 6% 6% 9% 29%	1967
	11th to 20th	Night	3 11% 3 12% 6% 6% 8% 5% 6% 9% 31%	1583
	21st to end	Night	4 10% 3 9% 6% 6% 6% 5% 8% 9% 34%	1600
May	1st to 10th	Night	5% 10% 3 8% 5% 5% 6% 4 7% 9% 37%	2800
	11th to 20th	Night	5% 11% 4 11% 7% 5% 5% 5% 7% 9% 32%	2702
	21st to end	Night	5% 7% 3 7% 5% 5% 5% 5% 7% 9% 41%	2491
June	1st to 10th	Night	12% 7% 3 7% 8% 5% 5% 5% 6% 9% 33%	796
	11th to 20th	Night	11% 10% 3 10% 7% 6% 6% 6% 7% 9% 25%	760
	21st to end	Night	7% 8% 2 7% 6% 6% 7% 8% 9% 11% 29%	760
July	1st to 10th	Night	6% 4 2 5% 5% 6% 6% 6% 10% 12% 38%	1260
	11th to 20th	Night	11% 9% 3 8% 7% 7% 6% 5% 6% 8% 29%	1511
	21st to end	Night	12% 8% 3 8% 6% 5% 7% 6% 8% 9% 28%	2066
August	1st to 10th	Night	6% 4 2 5% 5% 4 5% 4 7% 8% 50%	1978
	11th to 20th	Night	14% 8% 3 6% 4 5% 5% 4 6% 9% 36%	2424
	21st to end	Night	15% 11% 3 9% 5% 6% 7% 5% 6% 6% 26%	2794
September	1st to 10th	Night	13% 8% 3 10% 7% 7% 6% 5% 7% 6% 28%	1850
	11th to 20th	Night	8% 9% 3 9% 5% 5% 5% 5% 6% 9% 36%	1900
	21st to end	Night	13% 14% 4 10% 7% 7% 5% 4 6% 7% 24%	2159
October	1st to 10th	Night	11% 15% 3 9% 5% 6% 6% 6% 8% 8% 23%	3800
	11th to 20th	Night	10% 16% 6% 14% 6% 4 5% 4 5% 6% 24%	4108
	21st to end	Night	6% 18% 7% 13% 7% 5% 5% 4 6% 6% 22%	4821
November	1st to 10th	Night	5% 15% 7% 16% 10% 7% 7% 5% 7% 6% 15%	2926
	11th to 20th	Night	5% 17% 8% 16% 11% 8% 6% 6% 6% 6% 11%	3199
	21st to end	Night	3 13% 6% 15% 11% 8% 9% 6% 7% 7% 13%	3306
December	1st to 10th	Night	6% 15% 6% 13% 8% 7% 6% 5% 6% 7% 20%	5738
	11th to 20th	Night	2 10% 5% 16% 11% 8% 7% 6% 7% 9% 19%	6690
	21st to end	Night	4 16% 6% 16% 9% 8% 7% 6% 7% 7% 15%	8976

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% 14% 12% 10% 11% 1	2000
	11th to 20th	Day	53% 11% 12% 15% 9%	2444
	21st to end	Day	56% 10% 13% 10% 9% 2	3010
February	1st to 10th	Day	55% 10% 10% 13% 11% 1	1400
	11th to 20th	Day	53% 12% 13% 12% 10%	1565
	21st to end	Day	55% 10% 13% 16% 6%	1460
March	1st to 10th	Day	48% 8% 14% 18% 10% 1	4402
	11th to 20th	Day	52% 7% 17% 10% 11% 2	4733
	21st to end	Day	42% 11% 20% 20% 7% 1	5910
April	1st to 10th	Day	53% 10% 19% 14% 5%	2430
	11th to 20th	Day	50% 10% 14% 18% 8% 1	2766
	21st to end	Day	54% 9% 15% 16% 5%	2800
May	1st to 10th	Day	50% 9% 11% 18% 12%	7157
	11th to 20th	Day	53% 10% 13% 18% 6%	7196
	21st to end	Day	45% 7% 15% 19% 13%	8381
June	1st to 10th	Day	52% 8% 15% 18% 7% 1	3588
	11th to 20th	Day	55% 9% 15% 16% 3	3420
	21st to end	Day	53% 10% 17% 17% 3	3420
July	1st to 10th	Day	44% 10% 22% 19% 3	5611
	11th to 20th	Day	58% 11% 15% 14% 2	5351
	21st to end	Day	51% 9% 23% 16% 2	5313
August	1st to 10th	Day	36% 8% 19% 23% 12% 1	4934
	11th to 20th	Day	49% 7% 17% 21% 5%	4457
	21st to end	Day	55% 10% 19% 16% 1	4872
September	1st to 10th	Day	59% 10% 14% 15% 2	2327
	11th to 20th	Day	49% 9% 19% 20% 3	2280
	21st to end	Day	59% 9% 15% 15% 3	2021
October	1st to 10th	Day	61% 8% 12% 16% 2	3170
	11th to 20th	Day	56% 9% 17% 16% 2	2804
	21st to end	Day	62% 13% 17% 7% 1	2737
November	1st to 10th	Day	68% 11% 11% 8% 2	1372
	11th to 20th	Day	72% 7% 9% 10% 1	1200
	21st to end	Day	64% 12% 11% 7% 5%	1073
December	1st to 10th	Day	58% 12% 21% 6% 3	1440
	11th to 20th	Day	50% 15% 12% 14% 9%	1504
	21st to end	Day	62% 17% 8% 8% 5%	1980
January	1st to 10th	Night	60% 11% 8% 8% 12%	7990
	11th to 20th	Night	52% 9% 11% 15% 10% 2	7516
	21st to end	Night	56% 10% 13% 13% 6% 3	7945
February	1st to 10th	Night	55% 10% 11% 14% 8% 2	3000
	11th to 20th	Night	53% 14% 12% 13% 7% 1	2732
	21st to end	Night	52% 10% 14% 17% 7%	2169
March	1st to 10th	Night	49% 9% 13% 21% 8% 1	5472
	11th to 20th	Night	53% 8% 14% 16% 8% 1	5238
	21st to end	Night	45% 12% 18% 14% 12%	5041
April	1st to 10th	Night	47% 10% 20% 18% 5%	1967
	11th to 20th	Night	46% 9% 14% 22% 8%	1583
	21st to end	Night	40% 12% 16% 25% 8%	1600
May	1st to 10th	Night	37% 11% 12% 25% 15% 1	2797
	11th to 20th	Night	41% 12% 16% 18% 13% 1	2702
	21st to end	Night	34% 8% 14% 31% 13%	2491
June	1st to 10th	Night	45% 8% 16% 23% 8%	796
	11th to 20th	Night	49% 11% 17% 19% 4	760
	21st to end	Night	40% 13% 22% 20% 4	760
July	1st to 10th	Night	32% 11% 28% 25% 3	1240
	11th to 20th	Night	47% 10% 18% 22% 3	1484
	21st to end	Night	46% 11% 23% 18% 2	2000
August	1st to 10th	Night	29% 9% 22% 24% 14% 1	1972
	11th to 20th	Night	42% 9% 20% 23% 6%	2447
	21st to end	Night	53% 10% 17% 17% 2	2794
September	1st to 10th	Night	50% 12% 19% 17% 2	1850
	11th to 20th	Night	42% 10% 22% 22% 4	1900
	21st to end	Night	57% 8% 15% 17% 4	2159
October	1st to 10th	Night	52% 9% 15% 21% 3	3800
	11th to 20th	Night	58% 9% 12% 19% 2	4108
	21st to end	Night	60% 12% 16% 11% 2	4821
November	1st to 10th	Night	64% 12% 13% 9% 3	2926
	11th to 20th	Night	69% 10% 10% 9% 2	3199
	21st to end	Night	63% 11% 11% 12% 3	3306
December	1st to 10th	Night	58% 11% 17% 11% 2	5738
	11th to 20th	Night	54% 12% 15% 12% 6% 1	6687
	21st to end	Night	60% 13% 9% 9% 7% 1	8976

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	3 4 18% 35% 31% 9%	100
	11th to 20th	Day	8% 7% 16% 36% 17% 16%	140
	21st to end	Day	8% 12% 19% 41% 15% 6%	225
February	1st to 10th	Day	8% 6% 23% 37% 19% 7%	400
	11th to 20th	Day	7% 10% 26% 33% 18% 7%	395
	21st to end	Day	8% 11% 26% 34% 16% 4	331
March	1st to 10th	Day	6% 9% 27% 32% 17% 10%	400
	11th to 20th	Day	7% 11% 30% 27% 20% 6%	400
	21st to end	Day	6% 10% 26% 30% 20% 8%	535
April	1st to 10th	Day	7% 15% 29% 30% 15% 4	530
	11th to 20th	Day	10% 14% 26% 28% 18% 5%	690
	21st to end	Day	10% 17% 24% 29% 15% 5%	700
May	1st to 10th	Day	18% 20% 26% 24% 8% 3	703
	11th to 20th	Day	12% 15% 25% 27% 14% 7%	725
	21st to end	Day	12% 13% 26% 27% 18% 5%	909
June	1st to 10th	Day	15% 11% 22% 28% 20% 4	926
	11th to 20th	Day	16% 10% 20% 27% 22% 5%	870
	21st to end	Day	11% 8% 17% 30% 25% 9%	870
July	1st to 10th	Day	14% 7% 17% 31% 24% 7%	856
	11th to 20th	Day	17% 9% 17% 28% 22% 6%	706
	21st to end	Day	16% 7% 19% 24% 25% 8%	739
August	1st to 10th	Day	15% 8% 22% 29% 18% 9%	676
	11th to 20th	Day	24% 12% 24% 23% 14% 3	665
	21st to end	Day	23% 9% 23% 26% 14% 4	748
September	1st to 10th	Day	25% 13% 20% 18% 16% 7%	526
	11th to 20th	Day	14% 13% 21% 26% 18% 8%	490
	21st to end	Day	21% 18% 23% 21% 12% 5%	443
October	1st to 10th	Day	20% 17% 27% 21% 11% 4	390
	11th to 20th	Day	19% 17% 24% 23% 12% 6%	390
	21st to end	Day	13% 9% 24% 32% 18% 4	424
November	1st to 10th	Day	11% 10% 31% 28% 18% 3	200
	11th to 20th	Day	9% 6% 18% 34% 28% 6%	200
	21st to end	Day	5% 5% 28% 33% 19% 11%	200
December	1st to 10th	Day	3 6% 20% 43% 20% 8%	143
	11th to 20th	Day	6% 7% 19% 35% 23% 10%	100
	21st to end	Day	5% 5% 22% 37% 19% 13%	110
January	1st to 10th	Night	5% 4 24% 39% 23% 5%	1035
	11th to 20th	Night	8% 6% 30% 34% 18% 4	900
	21st to end	Night	8% 7% 29% 38% 15% 3	990
February	1st to 10th	Night	7% 6% 23% 42% 19% 2	900
	11th to 20th	Night	5% 6% 32% 36% 17% 4	884
	21st to end	Night	7% 6% 24% 42% 18% 3	743
March	1st to 10th	Night	3 8% 25% 35% 26% 4	822
	11th to 20th	Night	5% 7% 25% 34% 24% 6%	715
	21st to end	Night	3 8% 18% 31% 36% 4	660
April	1st to 10th	Night	4 7% 22% 36% 28% 4	600
	11th to 20th	Night	5% 7% 20% 32% 30% 5%	593
	21st to end	Night	7% 7% 19% 33% 30% 5%	600
May	1st to 10th	Night	8% 12% 22% 30% 24% 4	406
	11th to 20th	Night	9% 8% 21% 34% 26% 1	394
	21st to end	Night	7% 4 21% 37% 29% 1	348
June	1st to 10th	Night	12% 6% 21% 38% 21% 2	199
	11th to 20th	Night	12% 3 22% 35% 26% 2	190
	21st to end	Night	9% 5% 18% 34% 31% 4	190
July	1st to 10th	Night	11% 4 22% 30% 29% 4	185
	11th to 20th	Night	11% 4 17% 28% 35% 4	184
	21st to end	Night	12% 6% 23% 31% 24% 5%	416
August	1st to 10th	Night	11% 7% 18% 34% 25% 5%	424
	11th to 20th	Night	19% 8% 23% 28% 18% 4	564
	21st to end	Night	21% 4 20% 28% 23% 3	627
September	1st to 10th	Night	16% 9% 20% 27% 24% 3	570
	11th to 20th	Night	11% 7% 23% 30% 26% 4	570
	21st to end	Night	18% 12% 22% 29% 16% 3	739
October	1st to 10th	Night	19% 10% 24% 28% 17% 2	760
	11th to 20th	Night	19% 9% 21% 30% 18% 3	770
	21st to end	Night	12% 8% 26% 34% 18% 2	946
November	1st to 10th	Night	9% 7% 25% 38% 17% 4	880
	11th to 20th	Night	10% 7% 21% 33% 23% 5%	900
	21st to end	Night	8% 8% 26% 34% 20% 5%	1006
December	1st to 10th	Night	9% 7% 26% 37% 18% 4	1100
	11th to 20th	Night	8% 7% 24% 36% 21% 5%	1100
	21st to end	Night	9% 7% 24% 36% 19% 6%	1210

Page generated at 2025-06-07 06:28:15. Version ac07

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