First Frostless January

Since we moved to San Geronimo in 2011, January has warmed tremendously. Frosty days at or below 32 F have disappeared completely:

• 2012 - 31% of days were frosty, and 25% of days were in the 20s
• 2013 - 53% of days were frosty, and 30% of days were in the 20s
• 2014 - 58% of days were frosty, and 29% of days were in the 20s
• 2015 - 13% of days were frosty, and 10% of days were in the 20s
• 2016 - 7% of days were frosty, and both days were in the 20s
• 2017 - 16% of days were frosty, and for the first time no days were in the 20s
• 2018 - no frosty days

The green and blue minimum temperature lines show dramatic warming over the
last few years. Jan 2013-15 had less than 4% of average rainfall.

Luckily, this January follows a December when 63% of days were frosty. This ties 2013 for the most frosty days, well ahead of any other year.

I say "luckily" because just think of the implications of not having frost. It affects everything--fruit trees, insect activity... it also affects the length of the growing season, since February hasn't gotten below freezing since 2015 and March hasn't been below freezing since 2012.

And for only the second time in 7 years, January had no high temperatures in the 40s--the highs were at least 50 F all month. The lowest max is not shown on the graph.

Luckily, here it has rained enough to make it wetter than 2012 or 2014 at this point in the season. Unfortunately, those were our two driest years since 2011, at 70% and 51% of average, respectively.